[RFC,1/5] media: i2c: max2175: Add MAX2175 support

Message ID 1476281429-27603-2-git-send-email-ramesh.shanmugasundaram@bp.renesas.com (mailing list archive)
State Superseded, archived
Headers

Commit Message

Ramesh Shanmugasundaram Oct. 12, 2016, 2:10 p.m. UTC
  This patch adds driver support for MAX2175 chip. This is Maxim
Integrated's RF to Bits tuner front end chip designed for software-defined
radio solutions. This driver exposes the tuner as a sub-device instance
with standard and custom controls to configure the device.

Signed-off-by: Ramesh Shanmugasundaram <ramesh.shanmugasundaram@bp.renesas.com>
---
 .../devicetree/bindings/media/i2c/max2175.txt      |   60 +
 drivers/media/i2c/Kconfig                          |    4 +
 drivers/media/i2c/Makefile                         |    2 +
 drivers/media/i2c/max2175/Kconfig                  |    8 +
 drivers/media/i2c/max2175/Makefile                 |    4 +
 drivers/media/i2c/max2175/max2175.c                | 1624 ++++++++++++++++++++
 drivers/media/i2c/max2175/max2175.h                |  124 ++
 7 files changed, 1826 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/i2c/max2175.txt
 create mode 100644 drivers/media/i2c/max2175/Kconfig
 create mode 100644 drivers/media/i2c/max2175/Makefile
 create mode 100644 drivers/media/i2c/max2175/max2175.c
 create mode 100644 drivers/media/i2c/max2175/max2175.h
  

Comments

Geert Uytterhoeven Oct. 15, 2016, 12:42 p.m. UTC | #1
Hi Ramesh,

On Wed, Oct 12, 2016 at 4:10 PM, Ramesh Shanmugasundaram
<ramesh.shanmugasundaram@bp.renesas.com> wrote:
> This patch adds driver support for MAX2175 chip. This is Maxim
> Integrated's RF to Bits tuner front end chip designed for software-defined
> radio solutions. This driver exposes the tuner as a sub-device instance
> with standard and custom controls to configure the device.
>
> Signed-off-by: Ramesh Shanmugasundaram < for your patch!amesh.shanmugasundaram@bp.renesas.com>

Thanks for your patch!

> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/i2c/max2175.txt
> @@ -0,0 +1,60 @@
> +Maxim Integrated MAX2175 RF to Bits tuner
> +-----------------------------------------
> +
> +The MAX2175 IC is an advanced analog/digital hybrid-radio receiver with
> +RF to BitsĀ® front-end designed for software-defined radio solutions.
> +
> +Required properties:
> +--------------------
> +- compatible: "maxim,max2175" for MAX2175 RF-to-bits tuner.
> +- clocks: phandle to the fixed xtal clock.
> +- clock-names: name of the fixed xtal clock.
> +- port: video interface child port node of a tuner that defines the local
> +  and remote endpoints. The remote endpoint is assumed to be an SDR device
> +  that is capable of receiving the digital samples from the tuner.
> +
> +Optional properties:
> +--------------------
> +- maxim,slave     : empty property indicates this is a slave of another
> +                    master tuner. This is used to define two tuners in
> +                    diversity mode (1 master, 1 slave). By default each
> +                    tuner is an individual master.
> +- maxim,refout-load: load capacitance value (in pF) on reference output
> +                    drive level. The mapping of these load values to
> +                    respective bit values are given below.
> +                    0 - Reference output disabled
> +                    1 - 10pF load
> +                    2 - 20pF load
> +                    3 - 30pF load
> +                    4 - 40pF load
> +                    5 - 60pF load
> +                    6 - 70pF load

For properties involving units, usually the unit is made part of the
property name, e.g. maxim,refout-load-pF = 40.
This avoids confusion, and allows for extension later.

> +/* A tuner device instance under i2c bus */
> +max2175_0: tuner@60 {
> +       #clock-cells = <0>;
> +       compatible = "maxim,max2175";
> +       reg = <0x60>;
> +       clocks = <&maxim_xtal>;
> +       clock-names = "xtal";
> +       maxim,refout-load = <10>;

10 is not listed above. Perhaps you meant 10 pF?

> --- /dev/null
> +++ b/drivers/media/i2c/max2175/max2175.c
> @@ -0,0 +1,1624 @@

> +/* NOTE: Any addition/deletion in the below list should be reflected in
> + * max2175_modetag enum
> + */

You can drop the above comment if you make this explicit using C99
designated initializers, cfr. below.

> +static const struct max2175_rxmode eu_rx_modes[] = { /* Indexed by EU modetag */
> +       /* EU modes */
> +       { MAX2175_BAND_VHF, 182640000, 0, { 0, 0, 0, 0 } },

[MAX2175_DAB_1_2] = { MAX2175_BAND_VHF, 182640000, 0, { 0, 0, 0, 0 } },

> +};
> +
> +static const struct max2175_rxmode na_rx_modes[] = { /* Indexed by NA modetag */
> +       /* NA modes */
> +       { MAX2175_BAND_FM, 98255520, 1, { 0, 0, 0, 0 } },

[MAX2175_NA_FM_1_0] = { MAX2175_BAND_FM, 98255520, 1, { 0, 0, 0, 0 } },

> +struct max2175_ctx {
> +       struct v4l2_subdev sd;
> +       struct i2c_client *client;
> +       struct device *dev;
> +
> +       /* Cached configuration */
> +       u8 regs[256];
> +       enum max2175_modetag mode;      /* Receive mode tag */
> +       u32 freq;                       /* In Hz */
> +       struct max2175_rxmode *rx_modes;
> +
> +       /* Device settings */
> +       bool master;
> +       u32 decim_ratio;
> +       u64 xtal_freq;
> +
> +       /* ROM values */
> +       u8 rom_bbf_bw_am;
> +       u8 rom_bbf_bw_fm;
> +       u8 rom_bbf_bw_dab;
> +
> +       /* Local copy of old settings */
> +       u8 i2s_test;
> +
> +       u8 nbd_gain;
> +       u8 nbd_threshold;
> +       u8 wbd_gain;
> +       u8 wbd_threshold;
> +       u8 bbd_threshold;
> +       u8 bbdclip_threshold;
> +       u8 lt_wbd_threshold;
> +       u8 lt_wbd_gain;
> +
> +       /* Controls */
> +       struct v4l2_ctrl_handler ctrl_hdl;
> +       struct v4l2_ctrl *lna_gain;     /* LNA gain value */
> +       struct v4l2_ctrl *if_gain;      /* I/F gain value */
> +       struct v4l2_ctrl *pll_lock;     /* PLL lock */
> +       struct v4l2_ctrl *i2s_en;       /* I2S output enable */
> +       struct v4l2_ctrl *i2s_mode;     /* I2S mode value */
> +       struct v4l2_ctrl *am_hiz;       /* AM High impledance input */
> +       struct v4l2_ctrl *hsls;         /* High-side/Low-side polarity */
> +       struct v4l2_ctrl *rx_mode;      /* Receive mode */
> +
> +       /* Driver private variables */
> +       bool mode_resolved;             /* Flag to sanity check settings */
> +};

Sorting the struct members by decreasing size helps to avoid gaps due to
alignment restrictions, and may reduce memory consumption.

> +/* Flush local copy to device from idx to idx+len (inclusive) */
> +static void max2175_flush_regstore(struct max2175_ctx *ctx, u8 idx, u8 len)
> +{
> +       u8 i;

I'd just use unsigned int for loop counters.

> +
> +       for (i = idx; i <= len; i++)
> +               max2175_reg_write(ctx, i, ctx->regs[i]);
> +}

> +static int max2175_update_i2s_mode(struct max2175_ctx *ctx, u32 i2s_mode)
> +{
> +       /* Only change if it's new */
> +       if (max2175_read_bits(ctx, 29, 2, 0) == i2s_mode)

Many magic numbers, not only here (29, 2), but everywhere.
Can you please add #defines for these?

> +               return 0;
> +
> +       max2175_write_bits(ctx, 29, 2, 0, i2s_mode);
> +
> +       /* Based on I2S mode value I2S_WORD_CNT values change */
> +       if (i2s_mode == MAX2175_I2S_MODE3) {
> +               max2175_write_bits(ctx, 30, 6, 0, 1);
> +       } else if (i2s_mode == MAX2175_I2S_MODE2 ||
> +                  i2s_mode == MAX2175_I2S_MODE4) {
> +               max2175_write_bits(ctx, 30, 6, 0, 0);
> +       } else if (i2s_mode == MAX2175_I2S_MODE0) {
> +               max2175_write_bits(ctx, 30, 6, 0,
> +                                  ctx->rx_modes[ctx->mode].i2s_word_size);
> +       } else {
> +               v4l2_err(ctx->client,
> +                        "failed: i2s_mode %u unsupported\n", i2s_mode);
> +               return 1;
> +       }

switch (i2s_mode) { ... }

> +       mxm_dbg(ctx, "updated i2s_mode %u\n", i2s_mode);
> +       return 0;
> +}

> +static void max2175_set_filter_coeffs(struct max2175_ctx *ctx, u8 m_sel,
> +                                     u8 bank, const u16 *coeffs)
> +{
> +       u8 i, coeff_addr, upper_address;

I'd just use unsigned int for these.

> +
> +       mxm_dbg(ctx, "start: m_sel %d bank %d\n", m_sel, bank);
> +       max2175_write_bits(ctx, 114, 5, 4, m_sel);
> +
> +       if (m_sel == 2)
> +               upper_address = 12;
> +       else
> +               upper_address = 24;
> +
> +       max2175_set_bit(ctx, 117, 7, 1);
> +       for (i = 0; i < upper_address; i++) {
> +               coeff_addr = i + (bank * 24);
> +               max2175_set_bits(ctx, 115, 7, 0,
> +                                (u8)((coeffs[i] >> 8) & 0xff));
> +               max2175_set_bits(ctx, 116, 7, 0, (u8)(coeffs[i] & 0xff));

I don't think you need the casts to u8, or the masking with 0xff.

> +               max2175_set_bits(ctx, 117, 6, 0, coeff_addr);
> +               max2175_flush_regstore(ctx, 115, 3);
> +       }
> +       max2175_write_bit(ctx, 117, 7, 0);
> +}
> +
> +static void max2175_load_dab_1p2(struct max2175_ctx *ctx)
> +{
> +       u32 i;

unsigned int?

> +static int max2175_set_lo_freq(struct max2175_ctx *ctx, u64 lo_freq)
> +{
> +       int ret;
> +       u32 lo_mult;
> +       u64 scaled_lo_freq;
> +       const u64 scale_factor = 1000000ULL;
> +       u64 scaled_npf, scaled_integer, scaled_fraction;
> +       u32 frac_desired, int_desired;
> +       u8 loband_bits, vcodiv_bits;
> +
> +       scaled_lo_freq = lo_freq;
> +       /* Scale to larger number for precision */
> +       scaled_lo_freq = scaled_lo_freq * scale_factor * 100;
> +
> +       mxm_dbg(ctx, "scaled lo_freq %llu lo_freq %llu\n",
> +               scaled_lo_freq, lo_freq);
> +
> +       if (MAX2175_IS_BAND_AM(ctx)) {
> +               if (max2175_get_bit(ctx, 5, 7) == 0)
> +                       loband_bits = 0;
> +                       vcodiv_bits = 0;
> +                       lo_mult = 16;
> +       } else if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_FM) {
> +               if (lo_freq <= 74700000) {
> +                       loband_bits = 0;
> +                       vcodiv_bits = 0;
> +                       lo_mult = 16;
> +               } else if ((lo_freq > 74700000) && (lo_freq <= 110000000)) {
> +                       loband_bits = 1;
> +                       vcodiv_bits = 0;
> +               } else {
> +                       loband_bits = 1;
> +                       vcodiv_bits = 3;
> +               }
> +               lo_mult = 8;
> +       } else if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_VHF) {
> +               if (lo_freq <= 210000000) {
> +                       loband_bits = 2;
> +                       vcodiv_bits = 2;
> +               } else {
> +                       loband_bits = 2;
> +                       vcodiv_bits = 1;
> +               }
> +               lo_mult = 4;
> +       } else {
> +               loband_bits = 3;
> +               vcodiv_bits = 2;
> +               lo_mult = 2;
> +       }
> +
> +       if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_L)
> +               scaled_npf = (scaled_lo_freq / ctx->xtal_freq / lo_mult) / 100;
> +       else
> +               scaled_npf = (scaled_lo_freq / ctx->xtal_freq * lo_mult) / 100;

Please use one of the div64*() functions for divisions involving 64-bit
quantities (try to build for 32-bit and see). More of these below...

> +       scaled_integer = scaled_npf / scale_factor * scale_factor;
> +       int_desired = (u32)(scaled_npf / scale_factor);
> +       scaled_fraction = scaled_npf - scaled_integer;
> +       frac_desired = (u32)(scaled_fraction * 1048576 / scale_factor);

> +       /* Write the calculated values to the appropriate registers */
> +       max2175_set_bits(ctx, 5, 3, 2, loband_bits);
> +       max2175_set_bits(ctx, 6, 7, 6, vcodiv_bits);
> +       max2175_set_bits(ctx, 1, 7, 0, (u8)(int_desired & 0xff));
> +       max2175_set_bits(ctx, 2, 3, 0, (u8)((frac_desired >> 16) & 0x1f));
> +       max2175_set_bits(ctx, 3, 7, 0, (u8)((frac_desired >> 8) & 0xff));
> +       max2175_set_bits(ctx, 4, 7, 0, (u8)(frac_desired & 0xff));

No need for casts etc.

> +       /* Flush the above registers to device */
> +       max2175_flush_regstore(ctx, 1, 6);
> +       return ret;
> +}
> +
> +static int max2175_set_nco_freq(struct max2175_ctx *ctx, s64 nco_freq_desired)
> +{
> +       int ret;
> +       u64 clock_rate, abs_nco_freq;
> +       s64  nco_freq, nco_val_desired;
> +       u32 nco_reg;
> +       const u64 scale_factor = 1000000ULL;
> +
> +       mxm_dbg(ctx, "nco_freq: freq = %lld\n", nco_freq_desired);
> +       clock_rate = ctx->xtal_freq / ctx->decim_ratio;
> +       nco_freq = -nco_freq_desired;
> +
> +       if (nco_freq < 0)
> +               abs_nco_freq = -nco_freq;
> +       else
> +               abs_nco_freq = nco_freq;
> +
> +       /* Scale up the values for precision */
> +       if (abs_nco_freq < (clock_rate / 2)) {
> +               nco_val_desired = (2 * nco_freq * scale_factor) / clock_rate;
> +       } else {
> +               if (nco_freq < 0)
> +                       nco_val_desired = (-2 * (clock_rate - abs_nco_freq) *
> +                               scale_factor) / clock_rate;
> +               else
> +                       nco_val_desired = (2 * (clock_rate - abs_nco_freq) *
> +                               scale_factor) / clock_rate;
> +       }
> +
> +       /* Scale down to get the fraction */
> +       if (nco_freq < 0)
> +               nco_reg = 0x200000 + ((nco_val_desired * 1048576) /
> +                                     scale_factor);
> +       else
> +               nco_reg = (nco_val_desired * 1048576) / scale_factor;

More 64-bit divisions. In addition, the dividers are 64-bit too.
Can't they be 32-bit?

> +static int max2175_probe(struct i2c_client *client,
> +                       const struct i2c_device_id *id)
> +{
> +       struct max2175_ctx *ctx;
> +       struct device *dev = &client->dev;
> +       struct v4l2_subdev *sd;
> +       struct v4l2_ctrl_handler *hdl;
> +       struct clk *clk;
> +       bool master = true;
> +       u32 refout_load, refout_bits = 0;       /* REFOUT disabled */
> +       int ret;
> +
> +       /* Check if the adapter supports the needed features */
> +       if (!i2c_check_functionality(client->adapter,
> +                                    I2C_FUNC_SMBUS_BYTE_DATA)) {
> +               dev_err(&client->dev, "i2c check failed\n");
> +               return -EIO;
> +       }
> +
> +       if (of_find_property(client->dev.of_node, "maxim,slave", NULL))
> +               master = false;
> +
> +       if (!of_property_read_u32(client->dev.of_node, "maxim,refout-load",
> +                                &refout_load))
> +               refout_bits = max2175_refout_load_to_bits(client, refout_load);
> +
> +       clk = devm_clk_get(&client->dev, "xtal");
> +       if (IS_ERR(clk)) {
> +               ret = PTR_ERR(clk);
> +               dev_err(&client->dev, "cannot get xtal clock %d\n", ret);
> +               return -ENODEV;
> +       }
> +
> +       ctx = kzalloc(sizeof(struct max2175_ctx),
> +                            GFP_KERNEL);

devm_kzalloc()?

> +       if (ctx == NULL)
> +               return -ENOMEM;
> +
> +       sd = &ctx->sd;
> +       ctx->master = master;
> +       ctx->mode_resolved = false;
> +
> +       /* Set the defaults */
> +       ctx->freq = bands_rf.rangelow;
> +
> +       ctx->xtal_freq = clk_get_rate(clk);
> +       dev_info(&client->dev, "xtal freq %lluHz\n", ctx->xtal_freq);
> +
> +       v4l2_i2c_subdev_init(sd, client, &max2175_ops);
> +       ctx->client = client;
> +
> +       sd->flags = V4L2_SUBDEV_FL_HAS_DEVNODE;
> +       ctx->dev = dev;
> +
> +       /* Controls */
> +       hdl = &ctx->ctrl_hdl;
> +       ret = v4l2_ctrl_handler_init(hdl, 8);
> +       if (ret) {
> +               dev_err(&client->dev, "ctrl handler init failed\n");
> +               goto err;
> +       }
> +
> +       ctx->lna_gain = v4l2_ctrl_new_std(hdl, &max2175_ctrl_ops,
> +                                         V4L2_CID_RF_TUNER_LNA_GAIN,
> +                                         0, 15, 1, 2);
> +       ctx->lna_gain->flags |= (V4L2_CTRL_FLAG_VOLATILE |
> +                                V4L2_CTRL_FLAG_READ_ONLY);
> +       ctx->if_gain = v4l2_ctrl_new_std(hdl, &max2175_ctrl_ops,
> +                                        V4L2_CID_RF_TUNER_IF_GAIN,
> +                                        0, 31, 1, 0);
> +       ctx->if_gain->flags |= (V4L2_CTRL_FLAG_VOLATILE |
> +                               V4L2_CTRL_FLAG_READ_ONLY);
> +       ctx->pll_lock = v4l2_ctrl_new_std(hdl, &max2175_ctrl_ops,
> +                                         V4L2_CID_RF_TUNER_PLL_LOCK,
> +                                         0, 1, 1, 0);
> +       ctx->pll_lock->flags |= (V4L2_CTRL_FLAG_VOLATILE |
> +                                V4L2_CTRL_FLAG_READ_ONLY);
> +       ctx->i2s_en = v4l2_ctrl_new_custom(hdl, &max2175_i2s_en, NULL);
> +       ctx->i2s_mode = v4l2_ctrl_new_custom(hdl, &max2175_i2s_mode, NULL);
> +       ctx->am_hiz = v4l2_ctrl_new_custom(hdl, &max2175_am_hiz, NULL);
> +       ctx->hsls = v4l2_ctrl_new_custom(hdl, &max2175_hsls, NULL);
> +
> +       if (ctx->xtal_freq == MAX2175_EU_XTAL_FREQ) {
> +               ctx->rx_mode = v4l2_ctrl_new_custom(hdl,
> +                                                   &max2175_eu_rx_mode, NULL);
> +               ctx->rx_modes = (struct max2175_rxmode *)eu_rx_modes;
> +       } else {
> +               ctx->rx_mode = v4l2_ctrl_new_custom(hdl,
> +                                                   &max2175_na_rx_mode, NULL);
> +               ctx->rx_modes = (struct max2175_rxmode *)na_rx_modes;
> +       }

The casts are meant to cast away constness. Can that be avoided?

> --- /dev/null
> +++ b/drivers/media/i2c/max2175/max2175.h

> +/* NOTE: Any addition/deletion in the below enum should be reflected in
> + * V4L2_CID_MAX2175_RX_MODE ctrl strings

Which strings exactly?

> + */
> +enum max2175_modetag {
> +       /* EU modes */
> +       MAX2175_DAB_1_2 = 0,
> +
> +       /* Other possible modes to add in future
> +        * MAX2175_DAB_1_0,
> +        * MAX2175_DAB_1_3,
> +        * MAX2175_EU_FM_2_2,
> +        * MAX2175_EU_FM_1_0,
> +        * MAX2175_EU_FMHD_4_0,
> +        * MAX2175_EU_AM_1_0,
> +        * MAX2175_EU_AM_2_2,
> +        */
> +
> +       /* NA modes */
> +       MAX2175_NA_FM_1_0 = 0,
> +
> +       /* Other possible modes to add in future
> +        * MAX2175_NA_FM_1_2,
> +        * MAX2175_NA_FMHD_1_0,
> +        * MAX2175_NA_FMHD_1_2,
> +        * MAX2175_NA_AM_1_0,
> +        * MAX2175_NA_AM_1_2,
> +        */

The MAX2175_NA_* definitions share their values with the MAX2175_DAB_* and
future MAX2175_EU_* values. Do you have to use a single enum for both?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

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when I'm talking to journalists I just say "programmer" or something like that.
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Ramesh Shanmugasundaram Oct. 18, 2016, 3:04 p.m. UTC | #2
Hi Geert,

Thank you for the review. 

> Subject: Re: [RFC 1/5] media: i2c: max2175: Add MAX2175 support

> 

[...]
> 

> > --- /dev/null

> > +++ b/Documentation/devicetree/bindings/media/i2c/max2175.txt

> > @@ -0,0 +1,60 @@

> > +Maxim Integrated MAX2175 RF to Bits tuner

> > +-----------------------------------------

> > +

> > +The MAX2175 IC is an advanced analog/digital hybrid-radio receiver

> > +with RF to BitsĀ® front-end designed for software-defined radio

> solutions.

> > +

> > +Required properties:

> > +--------------------

> > +- compatible: "maxim,max2175" for MAX2175 RF-to-bits tuner.

> > +- clocks: phandle to the fixed xtal clock.

> > +- clock-names: name of the fixed xtal clock.

> > +- port: video interface child port node of a tuner that defines the

> > +local

> > +  and remote endpoints. The remote endpoint is assumed to be an SDR

> > +device

> > +  that is capable of receiving the digital samples from the tuner.

> > +

> > +Optional properties:

> > +--------------------

> > +- maxim,slave     : empty property indicates this is a slave of another

> > +                    master tuner. This is used to define two tuners in

> > +                    diversity mode (1 master, 1 slave). By default each

> > +                    tuner is an individual master.

> > +- maxim,refout-load: load capacitance value (in pF) on reference output

> > +                    drive level. The mapping of these load values to

> > +                    respective bit values are given below.

> > +                    0 - Reference output disabled

> > +                    1 - 10pF load

> > +                    2 - 20pF load

> > +                    3 - 30pF load

> > +                    4 - 40pF load

> > +                    5 - 60pF load

> > +                    6 - 70pF load

> 

> For properties involving units, usually the unit is made part of the

> property name, e.g. maxim,refout-load-pF = 40.

> This avoids confusion, and allows for extension later.


Agreed. I have modified it as

- maxim,refout-load-pF: load capacitance value (in pF) on reference
                        output drive level. The default is refout disabled
                        or no load. The possible load values are 
                        10pF
                        20pF
                        30pF
                        40pF
                        60pF
                        70pF

> 

> > +/* A tuner device instance under i2c bus */

> > +max2175_0: tuner@60 {

> > +       #clock-cells = <0>;

> > +       compatible = "maxim,max2175";

> > +       reg = <0x60>;

> > +       clocks = <&maxim_xtal>;

> > +       clock-names = "xtal";

> > +       maxim,refout-load = <10>;

> 

> 10 is not listed above. Perhaps you meant 10 pF?


Yes.

> 

> > --- /dev/null

> > +++ b/drivers/media/i2c/max2175/max2175.c

> > @@ -0,0 +1,1624 @@

> 

> > +/* NOTE: Any addition/deletion in the below list should be reflected

> > +in

> > + * max2175_modetag enum

> > + */

> 

> You can drop the above comment if you make this explicit using C99

> designated initializers, cfr. below.

> 

> > +static const struct max2175_rxmode eu_rx_modes[] = { /* Indexed by EU

> modetag */

> > +       /* EU modes */

> > +       { MAX2175_BAND_VHF, 182640000, 0, { 0, 0, 0, 0 } },

> 

> [MAX2175_DAB_1_2] = { MAX2175_BAND_VHF, 182640000, 0, { 0, 0, 0, 0 } },

> 

> > +};

> > +

> > +static const struct max2175_rxmode na_rx_modes[] = { /* Indexed by NA

> modetag */

> > +       /* NA modes */

> > +       { MAX2175_BAND_FM, 98255520, 1, { 0, 0, 0, 0 } },

> 

> [MAX2175_NA_FM_1_0] = { MAX2175_BAND_FM, 98255520, 1, { 0, 0, 0, 0 } },

> 


Thank you. Using designated initializers now.

> > +struct max2175_ctx {

> > +       struct v4l2_subdev sd;

> > +       struct i2c_client *client;

> > +       struct device *dev;

> > +

> > +       /* Cached configuration */

> > +       u8 regs[256];

> > +       enum max2175_modetag mode;      /* Receive mode tag */

> > +       u32 freq;                       /* In Hz */

> > +       struct max2175_rxmode *rx_modes;

> > +

> > +       /* Device settings */

> > +       bool master;

> > +       u32 decim_ratio;

> > +       u64 xtal_freq;

> > +

> > +       /* ROM values */

> > +       u8 rom_bbf_bw_am;

> > +       u8 rom_bbf_bw_fm;

> > +       u8 rom_bbf_bw_dab;

> > +

> > +       /* Local copy of old settings */

> > +       u8 i2s_test;

> > +

> > +       u8 nbd_gain;

> > +       u8 nbd_threshold;

> > +       u8 wbd_gain;

> > +       u8 wbd_threshold;

> > +       u8 bbd_threshold;

> > +       u8 bbdclip_threshold;

> > +       u8 lt_wbd_threshold;

> > +       u8 lt_wbd_gain;

> > +

> > +       /* Controls */

> > +       struct v4l2_ctrl_handler ctrl_hdl;

> > +       struct v4l2_ctrl *lna_gain;     /* LNA gain value */

> > +       struct v4l2_ctrl *if_gain;      /* I/F gain value */

> > +       struct v4l2_ctrl *pll_lock;     /* PLL lock */

> > +       struct v4l2_ctrl *i2s_en;       /* I2S output enable */

> > +       struct v4l2_ctrl *i2s_mode;     /* I2S mode value */

> > +       struct v4l2_ctrl *am_hiz;       /* AM High impledance input */

> > +       struct v4l2_ctrl *hsls;         /* High-side/Low-side polarity

> */

> > +       struct v4l2_ctrl *rx_mode;      /* Receive mode */

> > +

> > +       /* Driver private variables */

> > +       bool mode_resolved;             /* Flag to sanity check settings

> */

> > +};

> 

> Sorting the struct members by decreasing size helps to avoid gaps due to

> alignment restrictions, and may reduce memory consumption.


OK. I have corrected it to certain extent but still having groups (not strict decreasing order - for better readability). I have pushed the u8 group members to the end though.

> 

> > +/* Flush local copy to device from idx to idx+len (inclusive) */

> > +static void max2175_flush_regstore(struct max2175_ctx *ctx, u8 idx,

> > +u8 len) {

> > +       u8 i;

> 

> I'd just use unsigned int for loop counters.

> 


Agreed.

> > +

> > +       for (i = idx; i <= len; i++)

> > +               max2175_reg_write(ctx, i, ctx->regs[i]); }

> 

> > +static int max2175_update_i2s_mode(struct max2175_ctx *ctx, u32

> > +i2s_mode) {

> > +       /* Only change if it's new */

> > +       if (max2175_read_bits(ctx, 29, 2, 0) == i2s_mode)

> 

> Many magic numbers, not only here (29, 2), but everywhere.

> Can you please add #defines for these?


The Tuner provider is unwilling to disclose all register details. I agree on the readability issue with this restriction but this is somewhat true for some sensitive IPs in the media subsystem.

> 

> > +               return 0;

> > +

> > +       max2175_write_bits(ctx, 29, 2, 0, i2s_mode);

> > +

> > +       /* Based on I2S mode value I2S_WORD_CNT values change */

> > +       if (i2s_mode == MAX2175_I2S_MODE3) {

> > +               max2175_write_bits(ctx, 30, 6, 0, 1);

> > +       } else if (i2s_mode == MAX2175_I2S_MODE2 ||

> > +                  i2s_mode == MAX2175_I2S_MODE4) {

> > +               max2175_write_bits(ctx, 30, 6, 0, 0);

> > +       } else if (i2s_mode == MAX2175_I2S_MODE0) {

> > +               max2175_write_bits(ctx, 30, 6, 0,

> > +                                  ctx->rx_modes[ctx-

> >mode].i2s_word_size);

> > +       } else {

> > +               v4l2_err(ctx->client,

> > +                        "failed: i2s_mode %u unsupported\n", i2s_mode);

> > +               return 1;

> > +       }

> 

> switch (i2s_mode) { ... }


Agreed.

> 

> > +       mxm_dbg(ctx, "updated i2s_mode %u\n", i2s_mode);

> > +       return 0;

> > +}

> 

> > +static void max2175_set_filter_coeffs(struct max2175_ctx *ctx, u8

> m_sel,

> > +                                     u8 bank, const u16 *coeffs) {

> > +       u8 i, coeff_addr, upper_address;

> 

> I'd just use unsigned int for these.

> 


Agreed.

> > +

> > +       mxm_dbg(ctx, "start: m_sel %d bank %d\n", m_sel, bank);

> > +       max2175_write_bits(ctx, 114, 5, 4, m_sel);

> > +

> > +       if (m_sel == 2)

> > +               upper_address = 12;

> > +       else

> > +               upper_address = 24;

> > +

> > +       max2175_set_bit(ctx, 117, 7, 1);

> > +       for (i = 0; i < upper_address; i++) {

> > +               coeff_addr = i + (bank * 24);

> > +               max2175_set_bits(ctx, 115, 7, 0,

> > +                                (u8)((coeffs[i] >> 8) & 0xff));

> > +               max2175_set_bits(ctx, 116, 7, 0, (u8)(coeffs[i] &

> > + 0xff));

> 

> I don't think you need the casts to u8, or the masking with 0xff.


Yes. Corrected.

> 

> > +               max2175_set_bits(ctx, 117, 6, 0, coeff_addr);

> > +               max2175_flush_regstore(ctx, 115, 3);

> > +       }

> > +       max2175_write_bit(ctx, 117, 7, 0); }

> > +

> > +static void max2175_load_dab_1p2(struct max2175_ctx *ctx) {

> > +       u32 i;

> 

> unsigned int?


Agreed.

> 

> > +static int max2175_set_lo_freq(struct max2175_ctx *ctx, u64 lo_freq)

> > +{

> > +       int ret;

> > +       u32 lo_mult;

> > +       u64 scaled_lo_freq;

> > +       const u64 scale_factor = 1000000ULL;

> > +       u64 scaled_npf, scaled_integer, scaled_fraction;

> > +       u32 frac_desired, int_desired;

> > +       u8 loband_bits, vcodiv_bits;

> > +

> > +       scaled_lo_freq = lo_freq;

> > +       /* Scale to larger number for precision */

> > +       scaled_lo_freq = scaled_lo_freq * scale_factor * 100;

> > +

> > +       mxm_dbg(ctx, "scaled lo_freq %llu lo_freq %llu\n",

> > +               scaled_lo_freq, lo_freq);

> > +

> > +       if (MAX2175_IS_BAND_AM(ctx)) {

> > +               if (max2175_get_bit(ctx, 5, 7) == 0)

> > +                       loband_bits = 0;

> > +                       vcodiv_bits = 0;

> > +                       lo_mult = 16;

> > +       } else if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_FM) {

> > +               if (lo_freq <= 74700000) {

> > +                       loband_bits = 0;

> > +                       vcodiv_bits = 0;

> > +                       lo_mult = 16;

> > +               } else if ((lo_freq > 74700000) && (lo_freq <=

> 110000000)) {

> > +                       loband_bits = 1;

> > +                       vcodiv_bits = 0;

> > +               } else {

> > +                       loband_bits = 1;

> > +                       vcodiv_bits = 3;

> > +               }

> > +               lo_mult = 8;

> > +       } else if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_VHF) {

> > +               if (lo_freq <= 210000000) {

> > +                       loband_bits = 2;

> > +                       vcodiv_bits = 2;

> > +               } else {

> > +                       loband_bits = 2;

> > +                       vcodiv_bits = 1;

> > +               }

> > +               lo_mult = 4;

> > +       } else {

> > +               loband_bits = 3;

> > +               vcodiv_bits = 2;

> > +               lo_mult = 2;

> > +       }

> > +

> > +       if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_L)

> > +               scaled_npf = (scaled_lo_freq / ctx->xtal_freq / lo_mult)

> / 100;

> > +       else

> > +               scaled_npf = (scaled_lo_freq / ctx->xtal_freq *

> > + lo_mult) / 100;

> 

> Please use one of the div64*() functions for divisions involving 64-bit

> quantities (try to build for 32-bit and see). More of these below...


Thanks. All 64bit divisions are corrected to div_x64 variants. You are right - kbuild reported MIPS build failure because of this. I tried only x86 for 32-bit.

> 

> > +       scaled_integer = scaled_npf / scale_factor * scale_factor;

> > +       int_desired = (u32)(scaled_npf / scale_factor);

> > +       scaled_fraction = scaled_npf - scaled_integer;

> > +       frac_desired = (u32)(scaled_fraction * 1048576 /

> > + scale_factor);

> 

> > +       /* Write the calculated values to the appropriate registers */

> > +       max2175_set_bits(ctx, 5, 3, 2, loband_bits);

> > +       max2175_set_bits(ctx, 6, 7, 6, vcodiv_bits);

> > +       max2175_set_bits(ctx, 1, 7, 0, (u8)(int_desired & 0xff));

> > +       max2175_set_bits(ctx, 2, 3, 0, (u8)((frac_desired >> 16) &

> 0x1f));

> > +       max2175_set_bits(ctx, 3, 7, 0, (u8)((frac_desired >> 8) &

> 0xff));

> > +       max2175_set_bits(ctx, 4, 7, 0, (u8)(frac_desired & 0xff));

> 

> No need for casts etc.


Yes, corrected.

> 

> > +       /* Flush the above registers to device */

> > +       max2175_flush_regstore(ctx, 1, 6);

> > +       return ret;

> > +}

> > +

> > +static int max2175_set_nco_freq(struct max2175_ctx *ctx, s64

> > +nco_freq_desired) {

> > +       int ret;

> > +       u64 clock_rate, abs_nco_freq;

> > +       s64  nco_freq, nco_val_desired;

> > +       u32 nco_reg;

> > +       const u64 scale_factor = 1000000ULL;

> > +

> > +       mxm_dbg(ctx, "nco_freq: freq = %lld\n", nco_freq_desired);

> > +       clock_rate = ctx->xtal_freq / ctx->decim_ratio;

> > +       nco_freq = -nco_freq_desired;

> > +

> > +       if (nco_freq < 0)

> > +               abs_nco_freq = -nco_freq;

> > +       else

> > +               abs_nco_freq = nco_freq;

> > +

> > +       /* Scale up the values for precision */

> > +       if (abs_nco_freq < (clock_rate / 2)) {

> > +               nco_val_desired = (2 * nco_freq * scale_factor) /

> clock_rate;

> > +       } else {

> > +               if (nco_freq < 0)

> > +                       nco_val_desired = (-2 * (clock_rate -

> abs_nco_freq) *

> > +                               scale_factor) / clock_rate;

> > +               else

> > +                       nco_val_desired = (2 * (clock_rate -

> abs_nco_freq) *

> > +                               scale_factor) / clock_rate;

> > +       }

> > +

> > +       /* Scale down to get the fraction */

> > +       if (nco_freq < 0)

> > +               nco_reg = 0x200000 + ((nco_val_desired * 1048576) /

> > +                                     scale_factor);

> > +       else

> > +               nco_reg = (nco_val_desired * 1048576) / scale_factor;

> 

> More 64-bit divisions. In addition, the dividers are 64-bit too.

> Can't they be 32-bit?

> 


Agreed. The dividers need not be 32-bit. Corrected everywhere.

> > +static int max2175_probe(struct i2c_client *client,

> > +                       const struct i2c_device_id *id) {

> > +       struct max2175_ctx *ctx;

> > +       struct device *dev = &client->dev;

> > +       struct v4l2_subdev *sd;

> > +       struct v4l2_ctrl_handler *hdl;

> > +       struct clk *clk;

> > +       bool master = true;

> > +       u32 refout_load, refout_bits = 0;       /* REFOUT disabled */

> > +       int ret;

> > +

> > +       /* Check if the adapter supports the needed features */

> > +       if (!i2c_check_functionality(client->adapter,

> > +                                    I2C_FUNC_SMBUS_BYTE_DATA)) {

> > +               dev_err(&client->dev, "i2c check failed\n");

> > +               return -EIO;

> > +       }

> > +

> > +       if (of_find_property(client->dev.of_node, "maxim,slave", NULL))

> > +               master = false;

> > +

> > +       if (!of_property_read_u32(client->dev.of_node, "maxim,refout-

> load",

> > +                                &refout_load))

> > +               refout_bits = max2175_refout_load_to_bits(client,

> > + refout_load);

> > +

> > +       clk = devm_clk_get(&client->dev, "xtal");

> > +       if (IS_ERR(clk)) {

> > +               ret = PTR_ERR(clk);

> > +               dev_err(&client->dev, "cannot get xtal clock %d\n",

> ret);

> > +               return -ENODEV;

> > +       }

> > +

> > +       ctx = kzalloc(sizeof(struct max2175_ctx),

> > +                            GFP_KERNEL);

> 

> devm_kzalloc()?


Agreed & corrected. 

> 

> > +       if (ctx == NULL)

> > +               return -ENOMEM;

> > +

> > +       sd = &ctx->sd;

> > +       ctx->master = master;

> > +       ctx->mode_resolved = false;

> > +

> > +       /* Set the defaults */

> > +       ctx->freq = bands_rf.rangelow;

> > +

> > +       ctx->xtal_freq = clk_get_rate(clk);

> > +       dev_info(&client->dev, "xtal freq %lluHz\n", ctx->xtal_freq);

> > +

> > +       v4l2_i2c_subdev_init(sd, client, &max2175_ops);

> > +       ctx->client = client;

> > +

> > +       sd->flags = V4L2_SUBDEV_FL_HAS_DEVNODE;

> > +       ctx->dev = dev;

> > +

> > +       /* Controls */

> > +       hdl = &ctx->ctrl_hdl;

> > +       ret = v4l2_ctrl_handler_init(hdl, 8);

> > +       if (ret) {

> > +               dev_err(&client->dev, "ctrl handler init failed\n");

> > +               goto err;

> > +       }

> > +

> > +       ctx->lna_gain = v4l2_ctrl_new_std(hdl, &max2175_ctrl_ops,

> > +                                         V4L2_CID_RF_TUNER_LNA_GAIN,

> > +                                         0, 15, 1, 2);

> > +       ctx->lna_gain->flags |= (V4L2_CTRL_FLAG_VOLATILE |

> > +                                V4L2_CTRL_FLAG_READ_ONLY);

> > +       ctx->if_gain = v4l2_ctrl_new_std(hdl, &max2175_ctrl_ops,

> > +                                        V4L2_CID_RF_TUNER_IF_GAIN,

> > +                                        0, 31, 1, 0);

> > +       ctx->if_gain->flags |= (V4L2_CTRL_FLAG_VOLATILE |

> > +                               V4L2_CTRL_FLAG_READ_ONLY);

> > +       ctx->pll_lock = v4l2_ctrl_new_std(hdl, &max2175_ctrl_ops,

> > +                                         V4L2_CID_RF_TUNER_PLL_LOCK,

> > +                                         0, 1, 1, 0);

> > +       ctx->pll_lock->flags |= (V4L2_CTRL_FLAG_VOLATILE |

> > +                                V4L2_CTRL_FLAG_READ_ONLY);

> > +       ctx->i2s_en = v4l2_ctrl_new_custom(hdl, &max2175_i2s_en, NULL);

> > +       ctx->i2s_mode = v4l2_ctrl_new_custom(hdl, &max2175_i2s_mode,

> NULL);

> > +       ctx->am_hiz = v4l2_ctrl_new_custom(hdl, &max2175_am_hiz, NULL);

> > +       ctx->hsls = v4l2_ctrl_new_custom(hdl, &max2175_hsls, NULL);

> > +

> > +       if (ctx->xtal_freq == MAX2175_EU_XTAL_FREQ) {

> > +               ctx->rx_mode = v4l2_ctrl_new_custom(hdl,

> > +                                                   &max2175_eu_rx_mode,

> NULL);

> > +               ctx->rx_modes = (struct max2175_rxmode *)eu_rx_modes;

> > +       } else {

> > +               ctx->rx_mode = v4l2_ctrl_new_custom(hdl,

> > +                                                   &max2175_na_rx_mode,

> NULL);

> > +               ctx->rx_modes = (struct max2175_rxmode *)na_rx_modes;

> > +       }

> 

> The casts are meant to cast away constness. Can that be avoided?


Agreed. Made ctx->rx_modes member as const and avoided the cast here.
> 

> > --- /dev/null

> > +++ b/drivers/media/i2c/max2175/max2175.h

> 

> > +/* NOTE: Any addition/deletion in the below enum should be reflected

> > +in

> > + * V4L2_CID_MAX2175_RX_MODE ctrl strings

> 

> Which strings exactly?


It is supposed to be these two

+ */
+static const char * const max2175_ctrl_eu_rx_mode_strings[] = {
+	"DAB 1.2",
+	"NULL",
+};
+
+static const char * const max2175_ctrl_na_rx_mode_strings[] = {
+	"NA FM 1.0",
+	"NULL",
+};
+

I have corrected them now to use designated initializers. Thanks.

> 

> > + */

> > +enum max2175_modetag {

> > +       /* EU modes */

> > +       MAX2175_DAB_1_2 = 0,

> > +

> > +       /* Other possible modes to add in future

> > +        * MAX2175_DAB_1_0,

> > +        * MAX2175_DAB_1_3,

> > +        * MAX2175_EU_FM_2_2,

> > +        * MAX2175_EU_FM_1_0,

> > +        * MAX2175_EU_FMHD_4_0,

> > +        * MAX2175_EU_AM_1_0,

> > +        * MAX2175_EU_AM_2_2,

> > +        */

> > +

> > +       /* NA modes */

> > +       MAX2175_NA_FM_1_0 = 0,

> > +

> > +       /* Other possible modes to add in future

> > +        * MAX2175_NA_FM_1_2,

> > +        * MAX2175_NA_FMHD_1_0,

> > +        * MAX2175_NA_FMHD_1_2,

> > +        * MAX2175_NA_AM_1_0,

> > +        * MAX2175_NA_AM_1_2,

> > +        */

> 

> The MAX2175_NA_* definitions share their values with the MAX2175_DAB_* and

> future MAX2175_EU_* values. Do you have to use a single enum for both?

> 


I have made them separate enums now. NA_ modes were not tested yet.

I have also fixed few bugs in the meantime. I'll wait for this week for other media maintainers & experts to comment on the driver model & the new SDR format open item. Based on the response, I will post a new [PATCH] or [RFC v2] with these comments updated.

Thanks,
Ramesh
  
Laurent Pinchart Oct. 18, 2016, 7:25 p.m. UTC | #3
Hi Ramesh,

Thank you for the patch.

On Wednesday 12 Oct 2016 15:10:25 Ramesh Shanmugasundaram wrote:
> This patch adds driver support for MAX2175 chip. This is Maxim
> Integrated's RF to Bits tuner front end chip designed for software-defined
> radio solutions. This driver exposes the tuner as a sub-device instance
> with standard and custom controls to configure the device.
> 
> Signed-off-by: Ramesh Shanmugasundaram
> <ramesh.shanmugasundaram@bp.renesas.com> ---
>  .../devicetree/bindings/media/i2c/max2175.txt      |   60 +
>  drivers/media/i2c/Kconfig                          |    4 +
>  drivers/media/i2c/Makefile                         |    2 +
>  drivers/media/i2c/max2175/Kconfig                  |    8 +
>  drivers/media/i2c/max2175/Makefile                 |    4 +
>  drivers/media/i2c/max2175/max2175.c                | 1624 +++++++++++++++++
>  drivers/media/i2c/max2175/max2175.h                |  124 ++
>  7 files changed, 1826 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/i2c/max2175.txt
>  create mode 100644 drivers/media/i2c/max2175/Kconfig
>  create mode 100644 drivers/media/i2c/max2175/Makefile
>  create mode 100644 drivers/media/i2c/max2175/max2175.c
>  create mode 100644 drivers/media/i2c/max2175/max2175.h
> 
> diff --git a/Documentation/devicetree/bindings/media/i2c/max2175.txt
> b/Documentation/devicetree/bindings/media/i2c/max2175.txt new file mode
> 100644
> index 0000000..2250d5f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/i2c/max2175.txt
> @@ -0,0 +1,60 @@
> +Maxim Integrated MAX2175 RF to Bits tuner
> +-----------------------------------------
> +
> +The MAX2175 IC is an advanced analog/digital hybrid-radio receiver with
> +RF to BitsĀ® front-end designed for software-defined radio solutions.
> +
> +Required properties:
> +--------------------
> +- compatible: "maxim,max2175" for MAX2175 RF-to-bits tuner.
> +- clocks: phandle to the fixed xtal clock.
> +- clock-names: name of the fixed xtal clock.
> +- port: video interface child port node of a tuner that defines the local

As Rob pointed out in his review of patch 3/5, this isn't video.

> +  and remote endpoints. The remote endpoint is assumed to be an SDR device
> +  that is capable of receiving the digital samples from the tuner.
> +
> +Optional properties:
> +--------------------
> +- maxim,slave	   : empty property indicates this is a slave of 
another
> +		     master tuner. This is used to define two tuners in
> +		     diversity mode (1 master, 1 slave). By default each
> +		     tuner is an individual master.

Would it be useful to make that property a phandle to the master tuner, to 
give drivers a way to access the master ? I haven't checked whether there 
could be use cases for that.

> +- maxim,refout-load: load capacitance value (in pF) on reference output
> +		     drive level. The mapping of these load values to
> +		     respective bit values are given below.
> +		     0 - Reference output disabled
> +		     1 - 10pF load
> +		     2 - 20pF load
> +		     3 - 30pF load
> +		     4 - 40pF load
> +		     5 - 60pF load
> +		     6 - 70pF load

As Geert pointed out, you can simply specify the value in pF.

> +
> +Example:
> +--------
> +
> +Board specific DTS file
> +
> +/* Fixed XTAL clock node */
> +maxim_xtal: maximextal {
> +	compatible = "fixed-clock";
> +	#clock-cells = <0>;
> +	clock-frequency = <36864000>;
> +};
> +
> +/* A tuner device instance under i2c bus */
> +max2175_0: tuner@60 {
> +	#clock-cells = <0>;

Is the tuner a clock provider ? If it isn't you don't need this property.

> +	compatible = "maxim,max2175";
> +	reg = <0x60>;
> +	clocks = <&maxim_xtal>;
> +	clock-names = "xtal";
> +	maxim,refout-load = <10>;
> +
> +	port {
> +		max2175_0_ep: endpoint {
> +			remote-endpoint = <&slave_rx_v4l2_sdr_device>;
> +		};
> +	};
> +
> +};

[snip]

> diff --git a/drivers/media/i2c/max2175/Makefile
> b/drivers/media/i2c/max2175/Makefile new file mode 100644
> index 0000000..9bb46ac
> --- /dev/null
> +++ b/drivers/media/i2c/max2175/Makefile
> @@ -0,0 +1,4 @@
> +#
> +# Makefile for Maxim RF to Bits tuner device
> +#
> +obj-$(CONFIG_SDR_MAX2175) += max2175.o

If there's a single source file you might want to move it to 
drivers/media/i2c/.

> diff --git a/drivers/media/i2c/max2175/max2175.c
> b/drivers/media/i2c/max2175/max2175.c new file mode 100644
> index 0000000..71b60c2
> --- /dev/null
> +++ b/drivers/media/i2c/max2175/max2175.c
> @@ -0,0 +1,1624 @@
> +/*
> + * Maxim Integrated MAX2175 RF to Bits tuner driver
> + *
> + * This driver & most of the hard coded values are based on the reference
> + * application delivered by Maxim for this chip.
> + *
> + * Copyright (C) 2016 Maxim Integrated Products
> + * Copyright (C) 2016 Renesas Electronics Corporation
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2
> + * as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/errno.h>
> +#include <linux/i2c.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/delay.h>

You can move delay.h right below clk.h and everything will be in alphabetical 
order :-)

> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-of.h>
> +
> +#include "max2175.h"
> +
> +#define DRIVER_NAME "max2175"
> +
> +static unsigned int max2175_debug;
> +module_param(max2175_debug, uint, 0644);
> +MODULE_PARM_DESC(max2175_debug, "activate debug info");

You can name the parameter "debug".

> +#define mxm_dbg(ctx, fmt, arg...) \
> +	v4l2_dbg(1, max2175_debug, &ctx->sd, fmt, ## arg)

[snip]

> +/* Preset values:
> + * Based on Maxim MAX2175 Register Table revision: 130p10
> + */

The preferred multi-line comment style is

/*
 * foo
 * bar
 */

[snip]

> +struct max2175_ctx {

Nitpicking, such a structure would usually be named max2175 or max2175_device. 
Context seems to imply that you can have multiple of them per device.

> +	struct v4l2_subdev sd;
> +	struct i2c_client *client;
> +	struct device *dev;
> +
> +	/* Cached configuration */
> +	u8 regs[256];

If you want to cache register values you should use regmap.

> +	enum max2175_modetag mode;	/* Receive mode tag */
> +	u32 freq;			/* In Hz */
> +	struct max2175_rxmode *rx_modes;
> +
> +	/* Device settings */
> +	bool master;
> +	u32 decim_ratio;
> +	u64 xtal_freq;
> +
> +	/* ROM values */
> +	u8 rom_bbf_bw_am;
> +	u8 rom_bbf_bw_fm;
> +	u8 rom_bbf_bw_dab;
> +
> +	/* Local copy of old settings */
> +	u8 i2s_test;
> +
> +	u8 nbd_gain;
> +	u8 nbd_threshold;
> +	u8 wbd_gain;
> +	u8 wbd_threshold;
> +	u8 bbd_threshold;
> +	u8 bbdclip_threshold;
> +	u8 lt_wbd_threshold;
> +	u8 lt_wbd_gain;
> +
> +	/* Controls */
> +	struct v4l2_ctrl_handler ctrl_hdl;
> +	struct v4l2_ctrl *lna_gain;	/* LNA gain value */
> +	struct v4l2_ctrl *if_gain;	/* I/F gain value */
> +	struct v4l2_ctrl *pll_lock;	/* PLL lock */
> +	struct v4l2_ctrl *i2s_en;	/* I2S output enable */
> +	struct v4l2_ctrl *i2s_mode;	/* I2S mode value */
> +	struct v4l2_ctrl *am_hiz;	/* AM High impledance input */
> +	struct v4l2_ctrl *hsls;		/* High-side/Low-side polarity */
> +	struct v4l2_ctrl *rx_mode;	/* Receive mode */
> +
> +	/* Driver private variables */
> +	bool mode_resolved;		/* Flag to sanity check settings */
> +};

[snip]

> +/* Local store bitops helpers */
> +static u8 max2175_get_bits(struct max2175_ctx *ctx, u8 idx, u8 msb, u8 lsb)
> +{
> +	if (max2175_debug >= 2)
> +		mxm_dbg(ctx, "get_bits: idx:%u msb:%u lsb:%u\n",
> +			idx, msb, lsb);

Do we really need such detailed debugging ?

> +	return __max2175_get_bits(ctx->regs[idx], msb, lsb);
> +}
> +
> +static bool max2175_get_bit(struct max2175_ctx *ctx, u8 idx, u8 bit)
> +{
> +	return !!max2175_get_bits(ctx, idx, bit, bit);
> +}
> +
> +static void max2175_set_bits(struct max2175_ctx *ctx, u8 idx,
> +		      u8 msb, u8 lsb, u8 newval)
> +{
> +	if (max2175_debug >= 2)
> +		mxm_dbg(ctx, "set_bits: idx:%u msb:%u lsb:%u newval:%u\n",
> +			idx, msb, lsb, newval);
> +	ctx->regs[idx] = __max2175_set_bits(ctx->regs[idx], msb, lsb,
> +					      newval);
> +}
> +
> +static void max2175_set_bit(struct max2175_ctx *ctx, u8 idx, u8 bit, u8
> newval)
> +{
> +	max2175_set_bits(ctx, idx, bit, bit, newval);
> +}
> +
> +/* Device register bitops helpers */
> +static u8 max2175_read_bits(struct max2175_ctx *ctx, u8 idx, u8 msb, u8
> lsb)
> +{
> +	return __max2175_get_bits(max2175_reg_read(ctx, idx), msb, lsb);
> +}
> +
> +static void max2175_write_bits(struct max2175_ctx *ctx, u8 idx, u8 msb,
> +			u8 lsb, u8 newval)
> +{
> +	/* Update local copy & write to device */
> +	max2175_set_bits(ctx, idx, msb, lsb, newval);
> +	max2175_reg_write(ctx, idx, ctx->regs[idx]);
> +}
> +
> +static void max2175_write_bit(struct max2175_ctx *ctx, u8 idx, u8 bit,
> +			      u8 newval)
> +{
> +	if (max2175_debug >= 2)
> +		mxm_dbg(ctx, "idx %u, bit %u, newval %u\n", idx, bit, newval);
> +	max2175_write_bits(ctx, idx, bit, bit, newval);
> +}

Really, please use regmap :-)

> +static int max2175_poll_timeout(struct max2175_ctx *ctx, u8 idx, u8 msb, u8
> lsb,
> +				u8 exp_val, u32 timeout)
> +{
> +	unsigned long end = jiffies + msecs_to_jiffies(timeout);
> +	int ret;
> +
> +	do {
> +		ret = max2175_read_bits(ctx, idx, msb, lsb);
> +		if (ret < 0)
> +			return ret;
> +		if (ret == exp_val)
> +			return 0;
> +
> +		usleep_range(1000, 1500);
> +	} while (time_is_after_jiffies(end));
> +
> +	return -EBUSY;
> +}
> +
> +static int max2175_poll_csm_ready(struct max2175_ctx *ctx)
> +{
> +	return max2175_poll_timeout(ctx, 69, 1, 1, 0, 50);

Please define macros for register addresses and values, this is just 
unreadable.

> +}

[snip]

> +
> +#define MAX2175_IS_BAND_AM(ctx)		\
> +	(max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_AM)
> +
> +#define MAX2175_IS_FM_MODE(ctx)		\
> +	(max2175_get_bits(ctx, 12, 5, 4) == 0)
> +
> +#define MAX2175_IS_FMHD_MODE(ctx)	\
> +	(max2175_get_bits(ctx, 12, 5, 4) == 1)
> +
> +#define MAX2175_IS_DAB_MODE(ctx)	\
> +	(max2175_get_bits(ctx, 12, 5, 4) == 2)
> +
> +static int max2175_band_from_freq(u64 freq)
> +{
> +	if (freq >= 144000 && freq <= 26100000)
> +		return MAX2175_BAND_AM;
> +	else if (freq >= 65000000 && freq <= 108000000)
> +		return MAX2175_BAND_FM;
> +	else if (freq >= 160000000 && freq <= 240000000)
> +		return MAX2175_BAND_VHF;
> +
> +	/* Add other bands on need basis */
> +	return -ENOTSUPP;
> +}
> +
> +static int max2175_update_i2s_mode(struct max2175_ctx *ctx, u32 i2s_mode)
> +{
> +	/* Only change if it's new */
> +	if (max2175_read_bits(ctx, 29, 2, 0) == i2s_mode)
> +		return 0;
> +
> +	max2175_write_bits(ctx, 29, 2, 0, i2s_mode);
> +
> +	/* Based on I2S mode value I2S_WORD_CNT values change */
> +	if (i2s_mode == MAX2175_I2S_MODE3) {
> +		max2175_write_bits(ctx, 30, 6, 0, 1);
> +	} else if (i2s_mode == MAX2175_I2S_MODE2 ||
> +		   i2s_mode == MAX2175_I2S_MODE4) {
> +		max2175_write_bits(ctx, 30, 6, 0, 0);
> +	} else if (i2s_mode == MAX2175_I2S_MODE0) {
> +		max2175_write_bits(ctx, 30, 6, 0,
> +				   ctx->rx_modes[ctx->mode].i2s_word_size);
> +	} else {
> +		v4l2_err(ctx->client,
> +			 "failed: i2s_mode %u unsupported\n", i2s_mode);

This should never happen as the control framework will validate control 
values.

> +		return 1;

Error codes should be negative.

> +	}
> +	mxm_dbg(ctx, "updated i2s_mode %u\n", i2s_mode);
> +	return 0;
> +}

[snip]

> +static void max2175_load_dab_1p2(struct max2175_ctx *ctx)
> +{
> +	u32 i;

unsigned int will do, no need for an explicitly sized type.

> +
> +	/* Master is already set on init */
> +	for (i = 0; i < ARRAY_SIZE(dab12_map); i++)
> +		max2175_reg_write(ctx, dab12_map[i].idx, dab12_map[i].val);
> +
> +	/* The default settings assume master */
> +	if (!ctx->master)
> +		max2175_write_bit(ctx, 30, 7, 1);
> +
> +	/* Cache i2s_test value at this point */
> +	ctx->i2s_test = max2175_get_bits(ctx, 104, 3, 0);
> +	ctx->decim_ratio = 1;
> +
> +	/* Load the Channel Filter Coefficients into channel filter bank #2 */
> +	max2175_set_filter_coeffs(ctx, MAX2175_CH_MSEL, 2, ch_coeff_dab1);
> +}

[snip]

> +static bool max2175_set_csm_mode(struct max2175_ctx *ctx,
> +			  enum max2175_csm_mode new_mode)
> +{
> +	int ret = max2175_poll_csm_ready(ctx);
> +
> +	if (ret) {
> +		v4l2_err(ctx->client, "csm not ready: new mode %d\n", 
new_mode);
> +		return ret;
> +	}
> +
> +	mxm_dbg(ctx, "set csm mode: new mode %d\n", new_mode);
> +
> +	max2175_write_bits(ctx, 0, 2, 0, new_mode);
> +
> +	/* Wait for a fixed settle down time depending on new mode and band */
> +	switch (new_mode) {
> +	case MAX2175_CSM_MODE_JUMP_FAST_TUNE:
> +		if (MAX2175_IS_BAND_AM(ctx)) {
> +			usleep_range(1250, 1500);	/* 1.25ms */
> +		} else {
> +			if (MAX2175_IS_DAB_MODE(ctx))
> +				usleep_range(3000, 3500);	/* 3ms */
> +			else
> +				usleep_range(1250, 1500);	/* 1.25ms */
> +		}

You can write this as

		if (MAX2175_IS_BAND_AM(ctx))
			usleep_range(1250, 1500);	/* 1.25ms */
		else if (MAX2175_IS_DAB_MODE(ctx))
			usleep_range(3000, 3500);	/* 3ms */
		else
			usleep_range(1250, 1500);	/* 1.25ms */


> +		break;
> +
> +	/* Other mode switches can be added in the future if needed */
> +	default:
> +		break;
> +	}
> +
> +	ret = max2175_poll_csm_ready(ctx);
> +	if (ret) {
> +		v4l2_err(ctx->client, "csm did not settle: new mode %d\n",
> +			 new_mode);
> +		return ret;
> +	}
> +	return ret;
> +}

[snip]

> +
> +static int max2175_csm_action(struct max2175_ctx *ctx,
> +			      enum max2175_csm_mode action)
> +{
> +	int ret;
> +	int load_buffer = MAX2175_CSM_MODE_LOAD_TO_BUFFER;
> +
> +	mxm_dbg(ctx, "csm action: %d\n", action);
> +
> +	/* Perform one or two CSM mode commands. */
> +	switch (action)	{
> +	case MAX2175_CSM_MODE_NO_ACTION:
> +		/* Take no FSM Action. */
> +		return 0;
> +	case MAX2175_CSM_MODE_LOAD_TO_BUFFER:
> +	case MAX2175_CSM_MODE_PRESET_TUNE:
> +	case MAX2175_CSM_MODE_SEARCH:
> +	case MAX2175_CSM_MODE_AF_UPDATE:
> +	case MAX2175_CSM_MODE_JUMP_FAST_TUNE:
> +	case MAX2175_CSM_MODE_CHECK:
> +	case MAX2175_CSM_MODE_LOAD_AND_SWAP:
> +	case MAX2175_CSM_MODE_END:
> +		ret = max2175_set_csm_mode(ctx, action);
> +		break;
> +	case MAX2175_CSM_MODE_BUFFER_PLUS_PRESET_TUNE:
> +		ret = max2175_set_csm_mode(ctx, load_buffer);
> +		if (ret) {
> +			v4l2_err(ctx->client, "csm action %d load buf 
failed\n",
> +				 action);
> +			break;
> +		}
> +		ret = max2175_set_csm_mode(ctx, MAX2175_CSM_MODE_PRESET_TUNE);
> +		break;
> +	case MAX2175_CSM_MODE_BUFFER_PLUS_SEARCH:
> +		ret = max2175_set_csm_mode(ctx, load_buffer);
> +		if (ret) {
> +			v4l2_err(ctx->client, "csm action %d load buf 
failed\n",
> +				 action);
> +			break;
> +		}

Don't duplicate the error messages, move them after the switch statement.

> +		ret = max2175_set_csm_mode(ctx, MAX2175_CSM_MODE_SEARCH);
> +		break;
> +	case MAX2175_CSM_MODE_BUFFER_PLUS_AF_UPDATE:
> +		ret = max2175_set_csm_mode(ctx, load_buffer);
> +		if (ret) {
> +			v4l2_err(ctx->client, "csm action %d load buf 
failed\n",
> +				 action);
> +			break;
> +		}
> +		ret = max2175_set_csm_mode(ctx, MAX2175_CSM_MODE_AF_UPDATE);
> +		break;
> +	case MAX2175_CSM_MODE_BUFFER_PLUS_JUMP_FAST_TUNE:

This function is only called with action set to 
MAX2175_CSM_MODE_BUFFER_PLUS_JUMP_FAST_TUNE. I'd remove the rest of the code 
for now, unless you have a plan to use it soon.

> +		ret = max2175_set_csm_mode(ctx, load_buffer);
> +		if (ret) {
> +			v4l2_err(ctx->client, "csm action %d load buf 
failed\n",
> +				 action);
> +			break;
> +		}
> +		ret = max2175_set_csm_mode(ctx,
> +					   MAX2175_CSM_MODE_JUMP_FAST_TUNE);
> +		break;
> +	case MAX2175_CSM_MODE_BUFFER_PLUS_CHECK:
> +		ret = max2175_set_csm_mode(ctx, load_buffer);
> +		if (ret) {
> +			v4l2_err(ctx->client, "csm action %d load buf 
failed\n",
> +				 action);
> +			break;
> +		}
> +		ret = max2175_set_csm_mode(ctx, MAX2175_CSM_MODE_CHECK);
> +		break;
> +	case MAX2175_CSM_MODE_BUFFER_PLUS_LOAD_AND_SWAP:
> +		ret = max2175_set_csm_mode(ctx, load_buffer);
> +		if (ret) {
> +			v4l2_err(ctx->client, "csm action %d load buf 
failed\n",
> +				 action);
> +			break;
> +		}
> +		ret = max2175_set_csm_mode(ctx, 
MAX2175_CSM_MODE_LOAD_AND_SWAP);
> +		break;
> +	default:
> +		ret = max2175_set_csm_mode(ctx, MAX2175_CSM_MODE_NO_ACTION);
> +		break;
> +	}
> +	return ret;
> +}
> +
> +static int max2175_set_lo_freq(struct max2175_ctx *ctx, u64 lo_freq)
> +{
> +	int ret;
> +	u32 lo_mult;
> +	u64 scaled_lo_freq;
> +	const u64 scale_factor = 1000000ULL;
> +	u64 scaled_npf, scaled_integer, scaled_fraction;
> +	u32 frac_desired, int_desired;
> +	u8 loband_bits, vcodiv_bits;

Do you really support frequencies above 4GHz ? If not most of the 64-bit 
values could be stored in 32 bits.

> +
> +	scaled_lo_freq = lo_freq;
> +	/* Scale to larger number for precision */
> +	scaled_lo_freq = scaled_lo_freq * scale_factor * 100;
> +
> +	mxm_dbg(ctx, "scaled lo_freq %llu lo_freq %llu\n",
> +		scaled_lo_freq, lo_freq);
> +
> +	if (MAX2175_IS_BAND_AM(ctx)) {
> +		if (max2175_get_bit(ctx, 5, 7) == 0)
> +			loband_bits = 0;
> +			vcodiv_bits = 0;
> +			lo_mult = 16;
> +	} else if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_FM) {
> +		if (lo_freq <= 74700000) {
> +			loband_bits = 0;
> +			vcodiv_bits = 0;
> +			lo_mult = 16;
> +		} else if ((lo_freq > 74700000) && (lo_freq <= 110000000)) {

No need for the inner parentheses.

> +			loband_bits = 1;
> +			vcodiv_bits = 0;
> +		} else {
> +			loband_bits = 1;
> +			vcodiv_bits = 3;
> +		}
> +		lo_mult = 8;
> +	} else if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_VHF) {
> +		if (lo_freq <= 210000000) {
> +			loband_bits = 2;
> +			vcodiv_bits = 2;
> +		} else {
> +			loband_bits = 2;
> +			vcodiv_bits = 1;
> +		}
> +		lo_mult = 4;
> +	} else {
> +		loband_bits = 3;
> +		vcodiv_bits = 2;
> +		lo_mult = 2;
> +	}
> +
> +	if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_L)
> +		scaled_npf = (scaled_lo_freq / ctx->xtal_freq / lo_mult) / 
100;
> +	else
> +		scaled_npf = (scaled_lo_freq / ctx->xtal_freq * lo_mult) / 
100;
> +
> +	scaled_integer = scaled_npf / scale_factor * scale_factor;
> +	int_desired = (u32)(scaled_npf / scale_factor);
> +	scaled_fraction = scaled_npf - scaled_integer;
> +	frac_desired = (u32)(scaled_fraction * 1048576 / scale_factor);
> +
> +	/* Check CSM is not busy */
> +	ret = max2175_poll_csm_ready(ctx);
> +	if (ret) {
> +		v4l2_err(ctx->client, "lo_freq: csm busy. freq %llu\n",
> +			 lo_freq);
> +		return ret;
> +	}
> +
> +	mxm_dbg(ctx, "loband %u vcodiv %u lo_mult %u scaled_npf %llu\n",
> +		loband_bits, vcodiv_bits, lo_mult, scaled_npf);
> +	mxm_dbg(ctx, "scaled int %llu frac %llu desired int %u frac %u\n",
> +		scaled_integer, scaled_fraction, int_desired, frac_desired);
> +
> +	/* Write the calculated values to the appropriate registers */
> +	max2175_set_bits(ctx, 5, 3, 2, loband_bits);
> +	max2175_set_bits(ctx, 6, 7, 6, vcodiv_bits);
> +	max2175_set_bits(ctx, 1, 7, 0, (u8)(int_desired & 0xff));
> +	max2175_set_bits(ctx, 2, 3, 0, (u8)((frac_desired >> 16) & 0x1f));
> +	max2175_set_bits(ctx, 3, 7, 0, (u8)((frac_desired >> 8) & 0xff));
> +	max2175_set_bits(ctx, 4, 7, 0, (u8)(frac_desired & 0xff));
> +	/* Flush the above registers to device */
> +	max2175_flush_regstore(ctx, 1, 6);
> +	return ret;
> +}

[snip]

> +static int max2175_set_rf_freq_non_am_bands(struct max2175_ctx *ctx, u64
> freq,
> +					    u32 lo_pos)
> +{
> +	int ret;
> +	s64 adj_freq;
> +	u64 low_if_freq;
> +
> +	mxm_dbg(ctx, "rf_freq: non AM bands\n");
> +
> +	if (MAX2175_IS_FM_MODE(ctx))
> +		low_if_freq = 128000;
> +	else if (MAX2175_IS_FMHD_MODE(ctx))
> +		low_if_freq = 228000;
> +	else
> +		return max2175_set_lo_freq(ctx, freq);
> +
> +	if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_VHF) {

You perform this check in multiple places, you could create a helper function.

> +		if (lo_pos == MAX2175_LO_ABOVE_DESIRED)
> +			adj_freq = freq + low_if_freq;
> +		else
> +			adj_freq = freq - low_if_freq;
> +	} else {
> +		if (lo_pos == MAX2175_LO_ABOVE_DESIRED)
> +			adj_freq = freq - low_if_freq;
> +		else
> +			adj_freq = freq + low_if_freq;
> +	}

This could be written

	if ((max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_VHF) ==
	    (lo_pos == MAX2175_LO_ABOVE_DESIRED))
		adj_freq = freq + low_if_freq;
	else
		adj_freq = freq - low_if_freq;

Same for the other similar constructs in the driver. Up to you.

> +
> +	ret = max2175_set_lo_freq(ctx, adj_freq);
> +	if (ret)
> +		return ret;
> +
> +	return max2175_set_nco_freq(ctx, low_if_freq);
> +}

[snip]

> +#define max2175_ctx_from_sd(x)	\
> +	container_of(x, struct max2175_ctx, sd)
> +#define max2175_ctx_from_ctrl(x)	\
> +	container_of(x, struct max2175_ctx, ctrl_hdl)

I'd move it right after the structure definition, and turn them into static 
inline functions.

> +static int max2175_s_ctrl(struct v4l2_ctrl *ctrl)
> +{
> +	struct max2175_ctx *ctx = max2175_ctx_from_ctrl(ctrl->handler);
> +	int ret = 0;
> +
> +	mxm_dbg(ctx, "s_ctrl: id 0x%x, val %u\n", ctrl->id, ctrl->val);
> +	switch (ctrl->id) {
> +	case V4L2_CID_MAX2175_I2S_EN:
> +		max2175_i2s_enable(ctx, ctrl->val == 1);
> +		break;
> +	case V4L2_CID_MAX2175_I2S_MODE:
> +		max2175_s_ctrl_i2s_mode(ctx, ctrl->val);
> +		break;
> +	case V4L2_CID_MAX2175_AM_HIZ:
> +		v4l2_ctrl_activate(ctx->am_hiz, false);
> +		break;
> +	case V4L2_CID_MAX2175_HSLS:
> +		v4l2_ctrl_activate(ctx->hsls, false);
> +		break;
> +	case V4L2_CID_MAX2175_RX_MODE:
> +		mxm_dbg(ctx, "rx mode %u\n", ctrl->val);
> +		max2175_s_ctrl_rx_mode(ctx, ctrl->val);
> +		break;
> +	default:
> +		v4l2_err(ctx->client, "s:invalid ctrl id 0x%x\n", ctrl->id);
> +		ret = -EINVAL;

This should never happen. The driver has too many error and debug messages 
overall.

> +	}
> +
> +	return ret;
> +}
> +
> +static int max2175_get_lna_gain(struct max2175_ctx *ctx)
> +{
> +	int gain = 0;
> +	enum max2175_band band = max2175_get_bits(ctx, 5, 1, 0);
> +
> +	switch (band) {
> +	case MAX2175_BAND_AM:
> +		gain = max2175_read_bits(ctx, 51, 3, 1);
> +		break;
> +	case MAX2175_BAND_FM:
> +		gain = max2175_read_bits(ctx, 50, 3, 1);
> +		break;
> +	case MAX2175_BAND_VHF:
> +		gain = max2175_read_bits(ctx, 52, 3, 0);
> +		break;
> +	default:
> +		v4l2_err(ctx->client, "invalid band %d to get rf gain\n", 
band);

Can this happen ?

> +		break;
> +	}
> +	return gain;
> +}
> +
> +static int max2175_g_volatile_ctrl(struct v4l2_ctrl *ctrl)
> +{
> +	struct max2175_ctx *ctx = max2175_ctx_from_ctrl(ctrl->handler);
> +
> +	/* Only the dynamically changing values need to be in g_volatile_ctrl 
*/
> +	mxm_dbg(ctx, "g_volatile_ctrl: id 0x%x\n", ctrl->id);
> +	switch (ctrl->id) {
> +	case V4L2_CID_RF_TUNER_LNA_GAIN:
> +		ctrl->val = max2175_get_lna_gain(ctx);
> +		break;
> +	case V4L2_CID_RF_TUNER_IF_GAIN:
> +		ctrl->val = max2175_read_bits(ctx, 49, 4, 0);
> +		break;
> +	case V4L2_CID_RF_TUNER_PLL_LOCK:
> +		ctrl->val = (max2175_read_bits(ctx, 60, 7, 6) == 3);
> +		break;
> +	default:
> +		v4l2_err(ctx->client, "g:invalid ctrl id 0x%x\n", ctrl->id);

This should never happen either.

> +		return -EINVAL;
> +	}
> +	mxm_dbg(ctx, "g_volatile_ctrl: id 0x%x val %d\n", ctrl->id, ctrl-
>val);
> +	return 0;
> +};

[snip]

> +static const struct v4l2_ctrl_config max2175_i2s_en = {
> +	.ops = &max2175_ctrl_ops,
> +	.id = V4L2_CID_MAX2175_I2S_EN,

V4L2_CID_MAX2175_I2S_ENABLE ?

> +	.name = "I2S Enable",
> +	.type = V4L2_CTRL_TYPE_BOOLEAN,
> +	.min = 0,
> +	.max = 1,
> +	.step = 1,
> +	.def = 1,
> +};
> +
> +static const struct v4l2_ctrl_config max2175_i2s_mode = {
> +	.ops = &max2175_ctrl_ops,
> +	.id = V4L2_CID_MAX2175_I2S_MODE,
> +	.name = "I2S_MODE value",
> +	.type = V4L2_CTRL_TYPE_INTEGER,

Should this be a menu control ?

> +	.min = 0,
> +	.max = 4,
> +	.step = 1,
> +	.def = 0,
> +};
> +
> +static const struct v4l2_ctrl_config max2175_am_hiz = {
> +	.ops = &max2175_ctrl_ops,
> +	.id = V4L2_CID_MAX2175_AM_HIZ,
> +	.name = "AM High impedance input",
> +	.type = V4L2_CTRL_TYPE_BOOLEAN,
> +	.min = 0,
> +	.max = 1,
> +	.step = 1,
> +	.def = 0,
> +};
> +
> +static const struct v4l2_ctrl_config max2175_hsls = {
> +	.ops = &max2175_ctrl_ops,
> +	.id = V4L2_CID_MAX2175_HSLS,
> +	.name = "HSLS above/below desired",
> +	.type = V4L2_CTRL_TYPE_INTEGER,
> +	.min = 0,
> +	.max = 1,
> +	.step = 1,
> +	.def = 1,
> +};
> +
> +
> +/* NOTE: Any addition/deletion in the below list should be reflected in
> + * max2175_modetag enum
> + */
> +static const char * const max2175_ctrl_eu_rx_mode_strings[] = {
> +	"DAB 1.2",
> +	"NULL",

Do you really mean "NULL", not NULL ?

> +};
> +
> +static const char * const max2175_ctrl_na_rx_mode_strings[] = {
> +	"NA FM 1.0",
> +	"NULL",
> +};
> +
> +static const struct v4l2_ctrl_config max2175_eu_rx_mode = {
> +	.ops = &max2175_ctrl_ops,
> +	.id = V4L2_CID_MAX2175_RX_MODE,
> +	.name = "RX MODE",
> +	.type = V4L2_CTRL_TYPE_MENU,
> +	.max = ARRAY_SIZE(max2175_ctrl_eu_rx_mode_strings) - 2,

If there's a single mode supported I'd skip adding those controls for now.

> +	.def = 0,
> +	.qmenu = max2175_ctrl_eu_rx_mode_strings,
> +};
> +
> +static const struct v4l2_ctrl_config max2175_na_rx_mode = {
> +	.ops = &max2175_ctrl_ops,
> +	.id = V4L2_CID_MAX2175_RX_MODE,
> +	.name = "RX MODE",
> +	.type = V4L2_CTRL_TYPE_MENU,
> +	.max = ARRAY_SIZE(max2175_ctrl_na_rx_mode_strings) - 2,
> +	.def = 0,
> +	.qmenu = max2175_ctrl_na_rx_mode_strings,
> +};
> +
> +static u32 max2175_refout_load_to_bits(struct i2c_client *client, u32 load)
> +{
> +	u32 bits = 0;	/* REFOUT disabled */
> +
> +	if (load >= 0 && load <= 40)
> +		bits = load / 10;
> +	else if (load >= 60 && load <= 70)
> +		bits = load / 10 - 1;
> +	else
> +		dev_warn(&client->dev, "invalid refout_load %u\n", load);

Your DT bindings specify 0 as a valid value.

An invalid value specified in DT should be a fatal error.

> +
> +	return bits;
> +}
> +
> +static int max2175_probe(struct i2c_client *client,
> +			const struct i2c_device_id *id)
> +{
> +	struct max2175_ctx *ctx;
> +	struct device *dev = &client->dev;
> +	struct v4l2_subdev *sd;
> +	struct v4l2_ctrl_handler *hdl;
> +	struct clk *clk;
> +	bool master = true;
> +	u32 refout_load, refout_bits = 0;	/* REFOUT disabled */
> +	int ret;
> +
> +	/* Check if the adapter supports the needed features */
> +	if (!i2c_check_functionality(client->adapter,
> +				     I2C_FUNC_SMBUS_BYTE_DATA)) {
> +		dev_err(&client->dev, "i2c check failed\n");
> +		return -EIO;
> +	}
> +
> +	if (of_find_property(client->dev.of_node, "maxim,slave", NULL))
> +		master = false;
> +
> +	if (!of_property_read_u32(client->dev.of_node, "maxim,refout-load",
> +				 &refout_load))
> +		refout_bits = max2175_refout_load_to_bits(client, 
refout_load);
> +
> +	clk = devm_clk_get(&client->dev, "xtal");
> +	if (IS_ERR(clk)) {
> +		ret = PTR_ERR(clk);
> +		dev_err(&client->dev, "cannot get xtal clock %d\n", ret);
> +		return -ENODEV;
> +	}
> +
> +	ctx = kzalloc(sizeof(struct max2175_ctx),

sizeof(*ctx)

> +			     GFP_KERNEL);

This fits on one line.

> +	if (ctx == NULL)
> +		return -ENOMEM;
> +
> +	sd = &ctx->sd;
> +	ctx->master = master;
> +	ctx->mode_resolved = false;
> +
> +	/* Set the defaults */
> +	ctx->freq = bands_rf.rangelow;
> +
> +	ctx->xtal_freq = clk_get_rate(clk);
> +	dev_info(&client->dev, "xtal freq %lluHz\n", ctx->xtal_freq);
> +
> +	v4l2_i2c_subdev_init(sd, client, &max2175_ops);
> +	ctx->client = client;
> +
> +	sd->flags = V4L2_SUBDEV_FL_HAS_DEVNODE;
> +	ctx->dev = dev;
> +
> +	/* Controls */
> +	hdl = &ctx->ctrl_hdl;
> +	ret = v4l2_ctrl_handler_init(hdl, 8);
> +	if (ret) {
> +		dev_err(&client->dev, "ctrl handler init failed\n");
> +		goto err;
> +	}
> +
> +	ctx->lna_gain = v4l2_ctrl_new_std(hdl, &max2175_ctrl_ops,
> +					  V4L2_CID_RF_TUNER_LNA_GAIN,
> +					  0, 15, 1, 2);
> +	ctx->lna_gain->flags |= (V4L2_CTRL_FLAG_VOLATILE |
> +				 V4L2_CTRL_FLAG_READ_ONLY);
> +	ctx->if_gain = v4l2_ctrl_new_std(hdl, &max2175_ctrl_ops,
> +					 V4L2_CID_RF_TUNER_IF_GAIN,
> +					 0, 31, 1, 0);
> +	ctx->if_gain->flags |= (V4L2_CTRL_FLAG_VOLATILE |
> +				V4L2_CTRL_FLAG_READ_ONLY);
> +	ctx->pll_lock = v4l2_ctrl_new_std(hdl, &max2175_ctrl_ops,
> +					  V4L2_CID_RF_TUNER_PLL_LOCK,
> +					  0, 1, 1, 0);
> +	ctx->pll_lock->flags |= (V4L2_CTRL_FLAG_VOLATILE |
> +				 V4L2_CTRL_FLAG_READ_ONLY);
> +	ctx->i2s_en = v4l2_ctrl_new_custom(hdl, &max2175_i2s_en, NULL);
> +	ctx->i2s_mode = v4l2_ctrl_new_custom(hdl, &max2175_i2s_mode, NULL);
> +	ctx->am_hiz = v4l2_ctrl_new_custom(hdl, &max2175_am_hiz, NULL);
> +	ctx->hsls = v4l2_ctrl_new_custom(hdl, &max2175_hsls, NULL);
> +
> +	if (ctx->xtal_freq == MAX2175_EU_XTAL_FREQ) {
> +		ctx->rx_mode = v4l2_ctrl_new_custom(hdl,
> +						    &max2175_eu_rx_mode, 
NULL);
> +		ctx->rx_modes = (struct max2175_rxmode *)eu_rx_modes;
> +	} else {
> +		ctx->rx_mode = v4l2_ctrl_new_custom(hdl,
> +						    &max2175_na_rx_mode, 
NULL);
> +		ctx->rx_modes = (struct max2175_rxmode *)na_rx_modes;
> +	}
> +	ctx->sd.ctrl_handler = &ctx->ctrl_hdl;
> +
> +	ret = v4l2_async_register_subdev(sd);
> +	if (ret) {
> +		dev_err(&client->dev, "register subdev failed\n");
> +		goto err_reg;
> +	}
> +	dev_info(&client->dev, "subdev registered\n");
> +
> +	/* Initialize device */
> +	ret = max2175_core_init(ctx, refout_bits);
> +	if (ret)
> +		goto err_init;
> +
> +	mxm_dbg(ctx, "probed\n");
> +	return 0;
> +
> +err_init:
> +	v4l2_async_unregister_subdev(sd);
> +err_reg:
> +	v4l2_ctrl_handler_free(&ctx->ctrl_hdl);
> +err:
> +	kfree(ctx);
> +	return ret;
> +}
> +
> +static int max2175_remove(struct i2c_client *client)
> +{
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct max2175_ctx *ctx = max2175_ctx_from_sd(sd);
> +
> +	v4l2_ctrl_handler_free(&ctx->ctrl_hdl);
> +	v4l2_async_unregister_subdev(sd);
> +	mxm_dbg(ctx, "removed\n");
> +	kfree(ctx);
> +	return 0;
> +}
> +
> +static const struct i2c_device_id max2175_id[] = {
> +	{ DRIVER_NAME, 0},
> +	{},
> +};
> +

No need for a blank line here.

> +MODULE_DEVICE_TABLE(i2c, max2175_id);
> +
> +static const struct of_device_id max2175_of_ids[] = {
> +	{ .compatible = "maxim, max2175", },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, max2175_of_ids);
> +
> +static struct i2c_driver max2175_driver = {
> +	.driver = {
> +		.name	= DRIVER_NAME,
> +		.of_match_table = max2175_of_ids,
> +	},
> +	.probe		= max2175_probe,
> +	.remove		= max2175_remove,
> +	.id_table	= max2175_id,
> +};
> +
> +module_i2c_driver(max2175_driver);
> +
> +MODULE_DESCRIPTION("Maxim MAX2175 RF to Bits tuner driver");
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Ramesh Shanmugasundaram
> <ramesh.shanmugasundaram@bp.renesas.com>"); diff --git
> a/drivers/media/i2c/max2175/max2175.h b/drivers/media/i2c/max2175/max2175.h
> new file mode 100644
> index 0000000..61a508b
> --- /dev/null
> +++ b/drivers/media/i2c/max2175/max2175.h
> @@ -0,0 +1,124 @@
> +/*
> + * Maxim Integrated MAX2175 RF to Bits tuner driver
> + *
> + * This driver & most of the hard coded values are based on the reference
> + * application delivered by Maxim for this chip.
> + *
> + * Copyright (C) 2016 Maxim Integrated Products
> + * Copyright (C) 2016 Renesas Electronics Corporation
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2
> + * as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#ifndef __MAX2175_H__
> +#define __MAX2175_H__
> +
> +#include <linux/types.h>
> +
> +enum max2175_region {
> +	MAX2175_REGION_EU = 0,	/* Europe */
> +	MAX2175_REGION_NA,	/* North America */
> +};
> +
> +#define MAX2175_EU_XTAL_FREQ	(36864000)	/* In Hz */
> +#define MAX2175_NA_XTAL_FREQ	(40186125)	/* In Hz */
> +
> +enum max2175_band {
> +	MAX2175_BAND_AM = 0,
> +	MAX2175_BAND_FM,
> +	MAX2175_BAND_VHF,
> +	MAX2175_BAND_L,
> +};
> +
> +/* NOTE: Any addition/deletion in the below enum should be reflected in
> + * V4L2_CID_MAX2175_RX_MODE ctrl strings
> + */
> +enum max2175_modetag {
> +	/* EU modes */
> +	MAX2175_DAB_1_2 = 0,
> +
> +	/* Other possible modes to add in future
> +	 * MAX2175_DAB_1_0,
> +	 * MAX2175_DAB_1_3,
> +	 * MAX2175_EU_FM_2_2,
> +	 * MAX2175_EU_FM_1_0,
> +	 * MAX2175_EU_FMHD_4_0,
> +	 * MAX2175_EU_AM_1_0,
> +	 * MAX2175_EU_AM_2_2,
> +	 */
> +
> +	/* NA modes */
> +	MAX2175_NA_FM_1_0 = 0,
> +
> +	/* Other possible modes to add in future
> +	 * MAX2175_NA_FM_1_2,
> +	 * MAX2175_NA_FMHD_1_0,
> +	 * MAX2175_NA_FMHD_1_2,
> +	 * MAX2175_NA_AM_1_0,
> +	 * MAX2175_NA_AM_1_2,
> +	 */
> +};
> +
> +/* Supported I2S modes */
> +enum {
> +	MAX2175_I2S_MODE0 = 0,
> +	MAX2175_I2S_MODE1,
> +	MAX2175_I2S_MODE2,
> +	MAX2175_I2S_MODE3,
> +	MAX2175_I2S_MODE4,
> +};
> +
> +/* Coefficient table groups */
> +enum {
> +	MAX2175_CH_MSEL = 0,
> +	MAX2175_EQ_MSEL,
> +	MAX2175_AA_MSEL,
> +};
> +
> +/* HSLS LO injection polarity */
> +enum {
> +	MAX2175_LO_BELOW_DESIRED = 0,
> +	MAX2175_LO_ABOVE_DESIRED,
> +};
> +
> +/* Channel FSM modes */
> +enum max2175_csm_mode {
> +	MAX2175_CSM_MODE_LOAD_TO_BUFFER = 0,
> +	MAX2175_CSM_MODE_PRESET_TUNE,
> +	MAX2175_CSM_MODE_SEARCH,
> +	MAX2175_CSM_MODE_AF_UPDATE,
> +	MAX2175_CSM_MODE_JUMP_FAST_TUNE,
> +	MAX2175_CSM_MODE_CHECK,
> +	MAX2175_CSM_MODE_LOAD_AND_SWAP,
> +	MAX2175_CSM_MODE_END,
> +	MAX2175_CSM_MODE_BUFFER_PLUS_PRESET_TUNE,
> +	MAX2175_CSM_MODE_BUFFER_PLUS_SEARCH,
> +	MAX2175_CSM_MODE_BUFFER_PLUS_AF_UPDATE,
> +	MAX2175_CSM_MODE_BUFFER_PLUS_JUMP_FAST_TUNE,
> +	MAX2175_CSM_MODE_BUFFER_PLUS_CHECK,
> +	MAX2175_CSM_MODE_BUFFER_PLUS_LOAD_AND_SWAP,
> +	MAX2175_CSM_MODE_NO_ACTION
> +};
> +
> +/* Rx mode */
> +struct max2175_rxmode {
> +	enum max2175_band band;		/* Associated band */
> +	u32 freq;			/* Default freq in Hz */
> +	u8 i2s_word_size;		/* Bit value */
> +	u8 i2s_modes[4];		/* Supported modes */
> +};
> +
> +/* Register map */
> +struct max2175_regmap {
> +	u8 idx;				/* Register index */
> +	u8 val;				/* Register value */
> +};

As no other file than max2175.c includes this, I would move at least the 
structure definitions to the .c file.

> +#endif /* __MAX2175_H__ */
  
Ramesh Shanmugasundaram Oct. 21, 2016, 2:49 p.m. UTC | #4
Hi Laurent,

Thank you for the review comments.

> On Wednesday 12 Oct 2016 15:10:25 Ramesh Shanmugasundaram wrote:
> > This patch adds driver support for MAX2175 chip. This is Maxim
> > Integrated's RF to Bits tuner front end chip designed for
> > software-defined radio solutions. This driver exposes the tuner as a
> > sub-device instance with standard and custom controls to configure the
> device.
> >
> > Signed-off-by: Ramesh Shanmugasundaram
> > <ramesh.shanmugasundaram@bp.renesas.com> ---
> >  .../devicetree/bindings/media/i2c/max2175.txt      |   60 +
> >  drivers/media/i2c/Kconfig                          |    4 +
> >  drivers/media/i2c/Makefile                         |    2 +
> >  drivers/media/i2c/max2175/Kconfig                  |    8 +
> >  drivers/media/i2c/max2175/Makefile                 |    4 +
> >  drivers/media/i2c/max2175/max2175.c                | 1624
> +++++++++++++++++
> >  drivers/media/i2c/max2175/max2175.h                |  124 ++
> >  7 files changed, 1826 insertions(+)
> >  create mode 100644
> > Documentation/devicetree/bindings/media/i2c/max2175.txt
> >  create mode 100644 drivers/media/i2c/max2175/Kconfig  create mode
> > 100644 drivers/media/i2c/max2175/Makefile
> >  create mode 100644 drivers/media/i2c/max2175/max2175.c
> >  create mode 100644 drivers/media/i2c/max2175/max2175.h
> >
> > diff --git a/Documentation/devicetree/bindings/media/i2c/max2175.txt
> > b/Documentation/devicetree/bindings/media/i2c/max2175.txt new file
> > mode
> > 100644
> > index 0000000..2250d5f
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/media/i2c/max2175.txt
> > @@ -0,0 +1,60 @@
> > +Maxim Integrated MAX2175 RF to Bits tuner
> > +-----------------------------------------
> > +
> > +The MAX2175 IC is an advanced analog/digital hybrid-radio receiver
> > +with RF to Bits(r) front-end designed for software-defined radio
> solutions.
> > +
> > +Required properties:
> > +--------------------
> > +- compatible: "maxim,max2175" for MAX2175 RF-to-bits tuner.
> > +- clocks: phandle to the fixed xtal clock.
> > +- clock-names: name of the fixed xtal clock.
> > +- port: video interface child port node of a tuner that defines the
> > +local
> 
> As Rob pointed out in his review of patch 3/5, this isn't video.

Agreed & corrected.

> 
> > +  and remote endpoints. The remote endpoint is assumed to be an SDR
> > + device  that is capable of receiving the digital samples from the
> tuner.
> > +
> > +Optional properties:
> > +--------------------
> > +- maxim,slave	   : empty property indicates this is a slave of
> another
> > +		     master tuner. This is used to define two tuners in
> > +		     diversity mode (1 master, 1 slave). By default each
> > +		     tuner is an individual master.
> 
> Would it be useful to make that property a phandle to the master tuner, to
> give drivers a way to access the master ? I haven't checked whether there
> could be use cases for that.

As of now, I cannot find any use case for it from the datasheet. In future, we could add if such need arise.

> 
> > +- maxim,refout-load: load capacitance value (in pF) on reference output
> > +		     drive level. The mapping of these load values to
> > +		     respective bit values are given below.
> > +		     0 - Reference output disabled
> > +		     1 - 10pF load
> > +		     2 - 20pF load
> > +		     3 - 30pF load
> > +		     4 - 40pF load
> > +		     5 - 60pF load
> > +		     6 - 70pF load
> 
> As Geert pointed out, you can simply specify the value in pF.

Agreed & corrected.

> 
> > +
> > +Example:
> > +--------
> > +
> > +Board specific DTS file
> > +
> > +/* Fixed XTAL clock node */
> > +maxim_xtal: maximextal {
> > +	compatible = "fixed-clock";
> > +	#clock-cells = <0>;
> > +	clock-frequency = <36864000>;
> > +};
> > +
> > +/* A tuner device instance under i2c bus */
> > +max2175_0: tuner@60 {
> > +	#clock-cells = <0>;
> 
> Is the tuner a clock provider ? If it isn't you don't need this property.

Thanks. It's a copy/paste mistake :-(. Corrected.

> 
> > +	compatible = "maxim,max2175";
> > +	reg = <0x60>;
> > +	clocks = <&maxim_xtal>;
> > +	clock-names = "xtal";
> > +	maxim,refout-load = <10>;
> > +
> > +	port {
> > +		max2175_0_ep: endpoint {
> > +			remote-endpoint = <&slave_rx_v4l2_sdr_device>;
> > +		};
> > +	};
> > +
> > +};
> 
> [snip]
> 
> > diff --git a/drivers/media/i2c/max2175/Makefile
> > b/drivers/media/i2c/max2175/Makefile new file mode 100644 index
> > 0000000..9bb46ac
> > --- /dev/null
> > +++ b/drivers/media/i2c/max2175/Makefile
> > @@ -0,0 +1,4 @@
> > +#
> > +# Makefile for Maxim RF to Bits tuner device #
> > +obj-$(CONFIG_SDR_MAX2175) += max2175.o
> 
> If there's a single source file you might want to move it to
> drivers/media/i2c/.

MAX2175 is huge with lot more modes and functionality. When more modes are added (it's pre-set hex values), we may have to introduce the new file containing that the hex values alone. Hence, I thought of a folder. However, I cannot tell when the next set of modes will be added. So I'll remove the folder in the next patch.

> 
> > diff --git a/drivers/media/i2c/max2175/max2175.c
> > b/drivers/media/i2c/max2175/max2175.c new file mode 100644 index
> > 0000000..71b60c2
> > --- /dev/null
> > +++ b/drivers/media/i2c/max2175/max2175.c
> > @@ -0,0 +1,1624 @@
> > +/*
> > + * Maxim Integrated MAX2175 RF to Bits tuner driver
> > + *
> > + * This driver & most of the hard coded values are based on the
> > +reference
> > + * application delivered by Maxim for this chip.
> > + *
> > + * Copyright (C) 2016 Maxim Integrated Products
> > + * Copyright (C) 2016 Renesas Electronics Corporation
> > + *
> > + * This program is free software; you can redistribute it and/or
> > +modify
> > + * it under the terms of the GNU General Public License version 2
> > + * as published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> > + * GNU General Public License for more details.
> > + */
> > +
> > +#include <linux/clk.h>
> > +#include <linux/errno.h>
> > +#include <linux/i2c.h>
> > +#include <linux/init.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/slab.h>
> > +#include <linux/delay.h>
> 
> You can move delay.h right below clk.h and everything will be in
> alphabetical order :-)

Agreed.

> 
> > +#include <media/v4l2-ctrls.h>
> > +#include <media/v4l2-device.h>
> > +#include <media/v4l2-of.h>
> > +
> > +#include "max2175.h"
> > +
> > +#define DRIVER_NAME "max2175"
> > +
> > +static unsigned int max2175_debug;
> > +module_param(max2175_debug, uint, 0644);
> > +MODULE_PARM_DESC(max2175_debug, "activate debug info");
> 
> You can name the parameter "debug".

Agreed

> 
> > +#define mxm_dbg(ctx, fmt, arg...) \
> > +	v4l2_dbg(1, max2175_debug, &ctx->sd, fmt, ## arg)
> 
> [snip]
> 
> > +/* Preset values:
> > + * Based on Maxim MAX2175 Register Table revision: 130p10  */
> 
> The preferred multi-line comment style is
> 
> /*
>  * foo
>  * bar
>  */
> 
Agreed. I used it because checkpatch moaned but then I see Linus's comment :-).

> [snip]
> 
> > +struct max2175_ctx {
> 
> Nitpicking, such a structure would usually be named max2175 or
> max2175_device.
> Context seems to imply that you can have multiple of them per device.

Thanks for the explanation. I have changed it to max2175.

> 
> > +	struct v4l2_subdev sd;
> > +	struct i2c_client *client;
> > +	struct device *dev;
> > +
> > +	/* Cached configuration */
> > +	u8 regs[256];
> 
> If you want to cache register values you should use regmap.

Thanks. I did not know about regmap. I'll try this.

> 
> > +	enum max2175_modetag mode;	/* Receive mode tag */
> > +	u32 freq;			/* In Hz */
> > +	struct max2175_rxmode *rx_modes;
> > +
> > +	/* Device settings */
> > +	bool master;
> > +	u32 decim_ratio;
> > +	u64 xtal_freq;
> > +
> > +	/* ROM values */
> > +	u8 rom_bbf_bw_am;
> > +	u8 rom_bbf_bw_fm;
> > +	u8 rom_bbf_bw_dab;
> > +
> > +	/* Local copy of old settings */
> > +	u8 i2s_test;
> > +
> > +	u8 nbd_gain;
> > +	u8 nbd_threshold;
> > +	u8 wbd_gain;
> > +	u8 wbd_threshold;
> > +	u8 bbd_threshold;
> > +	u8 bbdclip_threshold;
> > +	u8 lt_wbd_threshold;
> > +	u8 lt_wbd_gain;
> > +
> > +	/* Controls */
> > +	struct v4l2_ctrl_handler ctrl_hdl;
> > +	struct v4l2_ctrl *lna_gain;	/* LNA gain value */
> > +	struct v4l2_ctrl *if_gain;	/* I/F gain value */
> > +	struct v4l2_ctrl *pll_lock;	/* PLL lock */
> > +	struct v4l2_ctrl *i2s_en;	/* I2S output enable */
> > +	struct v4l2_ctrl *i2s_mode;	/* I2S mode value */
> > +	struct v4l2_ctrl *am_hiz;	/* AM High impledance input */
> > +	struct v4l2_ctrl *hsls;		/* High-side/Low-side polarity */
> > +	struct v4l2_ctrl *rx_mode;	/* Receive mode */
> > +
> > +	/* Driver private variables */
> > +	bool mode_resolved;		/* Flag to sanity check settings */
> > +};
> 
> [snip]
> 
> > +/* Local store bitops helpers */
> > +static u8 max2175_get_bits(struct max2175_ctx *ctx, u8 idx, u8 msb,
> > +u8 lsb) {
> > +	if (max2175_debug >= 2)
> > +		mxm_dbg(ctx, "get_bits: idx:%u msb:%u lsb:%u\n",
> > +			idx, msb, lsb);
> 
> Do we really need such detailed debugging ?

Unfortunately yes. I'll try to remove this after some more testing or may be later as a separate patch.
I have converted a Windows GUI app code to this driver. Most of the register details & configuration sequence are not available in the datasheet. I used similar pattern of log message as in GUI logs because it helps in testing :-(

> 
> > +	return __max2175_get_bits(ctx->regs[idx], msb, lsb); }
> > +
> > +static bool max2175_get_bit(struct max2175_ctx *ctx, u8 idx, u8 bit)
> > +{
> > +	return !!max2175_get_bits(ctx, idx, bit, bit); }
> > +
> > +static void max2175_set_bits(struct max2175_ctx *ctx, u8 idx,
> > +		      u8 msb, u8 lsb, u8 newval)
> > +{
> > +	if (max2175_debug >= 2)
> > +		mxm_dbg(ctx, "set_bits: idx:%u msb:%u lsb:%u newval:%u\n",
> > +			idx, msb, lsb, newval);
> > +	ctx->regs[idx] = __max2175_set_bits(ctx->regs[idx], msb, lsb,
> > +					      newval);
> > +}
> > +
> > +static void max2175_set_bit(struct max2175_ctx *ctx, u8 idx, u8 bit,
> > +u8
> > newval)
> > +{
> > +	max2175_set_bits(ctx, idx, bit, bit, newval); }
> > +
> > +/* Device register bitops helpers */
> > +static u8 max2175_read_bits(struct max2175_ctx *ctx, u8 idx, u8 msb,
> > +u8
> > lsb)
> > +{
> > +	return __max2175_get_bits(max2175_reg_read(ctx, idx), msb, lsb); }
> > +
> > +static void max2175_write_bits(struct max2175_ctx *ctx, u8 idx, u8 msb,
> > +			u8 lsb, u8 newval)
> > +{
> > +	/* Update local copy & write to device */
> > +	max2175_set_bits(ctx, idx, msb, lsb, newval);
> > +	max2175_reg_write(ctx, idx, ctx->regs[idx]); }
> > +
> > +static void max2175_write_bit(struct max2175_ctx *ctx, u8 idx, u8 bit,
> > +			      u8 newval)
> > +{
> > +	if (max2175_debug >= 2)
> > +		mxm_dbg(ctx, "idx %u, bit %u, newval %u\n", idx, bit, newval);
> > +	max2175_write_bits(ctx, idx, bit, bit, newval); }
> 
> Really, please use regmap :-)

Agreed.

> 
> > +static int max2175_poll_timeout(struct max2175_ctx *ctx, u8 idx, u8
> > +msb, u8
> > lsb,
> > +				u8 exp_val, u32 timeout)
> > +{
> > +	unsigned long end = jiffies + msecs_to_jiffies(timeout);
> > +	int ret;
> > +
> > +	do {
> > +		ret = max2175_read_bits(ctx, idx, msb, lsb);
> > +		if (ret < 0)
> > +			return ret;
> > +		if (ret == exp_val)
> > +			return 0;
> > +
> > +		usleep_range(1000, 1500);
> > +	} while (time_is_after_jiffies(end));
> > +
> > +	return -EBUSY;
> > +}
> > +
> > +static int max2175_poll_csm_ready(struct max2175_ctx *ctx) {
> > +	return max2175_poll_timeout(ctx, 69, 1, 1, 0, 50);
> 
> Please define macros for register addresses and values, this is just
> unreadable.

The Tuner provider is unwilling to disclose all register details. I agree on the readability issue with this restriction but this is somewhat true for some sensitive IPs in the media subsystem.

> 
> > +}
> 
> [snip]
> 
> > +
> > +#define MAX2175_IS_BAND_AM(ctx)		\
> > +	(max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_AM)
> > +
> > +#define MAX2175_IS_FM_MODE(ctx)		\
> > +	(max2175_get_bits(ctx, 12, 5, 4) == 0)
> > +
> > +#define MAX2175_IS_FMHD_MODE(ctx)	\
> > +	(max2175_get_bits(ctx, 12, 5, 4) == 1)
> > +
> > +#define MAX2175_IS_DAB_MODE(ctx)	\
> > +	(max2175_get_bits(ctx, 12, 5, 4) == 2)
> > +
> > +static int max2175_band_from_freq(u64 freq) {
> > +	if (freq >= 144000 && freq <= 26100000)
> > +		return MAX2175_BAND_AM;
> > +	else if (freq >= 65000000 && freq <= 108000000)
> > +		return MAX2175_BAND_FM;
> > +	else if (freq >= 160000000 && freq <= 240000000)
> > +		return MAX2175_BAND_VHF;
> > +
> > +	/* Add other bands on need basis */
> > +	return -ENOTSUPP;
> > +}
> > +
> > +static int max2175_update_i2s_mode(struct max2175_ctx *ctx, u32
> > +i2s_mode) {
> > +	/* Only change if it's new */
> > +	if (max2175_read_bits(ctx, 29, 2, 0) == i2s_mode)
> > +		return 0;
> > +
> > +	max2175_write_bits(ctx, 29, 2, 0, i2s_mode);
> > +
> > +	/* Based on I2S mode value I2S_WORD_CNT values change */
> > +	if (i2s_mode == MAX2175_I2S_MODE3) {
> > +		max2175_write_bits(ctx, 30, 6, 0, 1);
> > +	} else if (i2s_mode == MAX2175_I2S_MODE2 ||
> > +		   i2s_mode == MAX2175_I2S_MODE4) {
> > +		max2175_write_bits(ctx, 30, 6, 0, 0);
> > +	} else if (i2s_mode == MAX2175_I2S_MODE0) {
> > +		max2175_write_bits(ctx, 30, 6, 0,
> > +				   ctx->rx_modes[ctx->mode].i2s_word_size);
> > +	} else {
> > +		v4l2_err(ctx->client,
> > +			 "failed: i2s_mode %u unsupported\n", i2s_mode);
> 
> This should never happen as the control framework will validate control
> values.

Agreed.

> 
> > +		return 1;
> 
> Error codes should be negative.

Agreed.

> 
> > +	}
> > +	mxm_dbg(ctx, "updated i2s_mode %u\n", i2s_mode);
> > +	return 0;
> > +}
> 
> [snip]
> 
> > +static void max2175_load_dab_1p2(struct max2175_ctx *ctx) {
> > +	u32 i;
> 
> unsigned int will do, no need for an explicitly sized type.

Agreed.

> 
> > +
> > +	/* Master is already set on init */
> > +	for (i = 0; i < ARRAY_SIZE(dab12_map); i++)
> > +		max2175_reg_write(ctx, dab12_map[i].idx, dab12_map[i].val);
> > +
> > +	/* The default settings assume master */
> > +	if (!ctx->master)
> > +		max2175_write_bit(ctx, 30, 7, 1);
> > +
> > +	/* Cache i2s_test value at this point */
> > +	ctx->i2s_test = max2175_get_bits(ctx, 104, 3, 0);
> > +	ctx->decim_ratio = 1;
> > +
> > +	/* Load the Channel Filter Coefficients into channel filter bank #2
> */
> > +	max2175_set_filter_coeffs(ctx, MAX2175_CH_MSEL, 2, ch_coeff_dab1); }
> 
> [snip]
> 
> > +static bool max2175_set_csm_mode(struct max2175_ctx *ctx,
> > +			  enum max2175_csm_mode new_mode)
> > +{
> > +	int ret = max2175_poll_csm_ready(ctx);
> > +
> > +	if (ret) {
> > +		v4l2_err(ctx->client, "csm not ready: new mode %d\n",
> new_mode);
> > +		return ret;
> > +	}
> > +
> > +	mxm_dbg(ctx, "set csm mode: new mode %d\n", new_mode);
> > +
> > +	max2175_write_bits(ctx, 0, 2, 0, new_mode);
> > +
> > +	/* Wait for a fixed settle down time depending on new mode and band
> */
> > +	switch (new_mode) {
> > +	case MAX2175_CSM_MODE_JUMP_FAST_TUNE:
> > +		if (MAX2175_IS_BAND_AM(ctx)) {
> > +			usleep_range(1250, 1500);	/* 1.25ms */
> > +		} else {
> > +			if (MAX2175_IS_DAB_MODE(ctx))
> > +				usleep_range(3000, 3500);	/* 3ms */
> > +			else
> > +				usleep_range(1250, 1500);	/* 1.25ms */
> > +		}
> 
> You can write this as
> 
> 		if (MAX2175_IS_BAND_AM(ctx))
> 			usleep_range(1250, 1500);	/* 1.25ms */
> 		else if (MAX2175_IS_DAB_MODE(ctx))
> 			usleep_range(3000, 3500);	/* 3ms */
> 		else
> 			usleep_range(1250, 1500);	/* 1.25ms */

Agreed.

> 
> 
> > +		break;
> > +
> > +	/* Other mode switches can be added in the future if needed */
> > +	default:
> > +		break;
> > +	}
> > +
> > +	ret = max2175_poll_csm_ready(ctx);
> > +	if (ret) {
> > +		v4l2_err(ctx->client, "csm did not settle: new mode %d\n",
> > +			 new_mode);
> > +		return ret;
> > +	}
> > +	return ret;
> > +}
> 
> [snip]
> 
> > +
> > +static int max2175_csm_action(struct max2175_ctx *ctx,
> > +			      enum max2175_csm_mode action) {
> > +	int ret;
> > +	int load_buffer = MAX2175_CSM_MODE_LOAD_TO_BUFFER;
> > +
> > +	mxm_dbg(ctx, "csm action: %d\n", action);
> > +
> > +	/* Perform one or two CSM mode commands. */
> > +	switch (action)	{
> > +	case MAX2175_CSM_MODE_NO_ACTION:
> > +		/* Take no FSM Action. */
> > +		return 0;
> > +	case MAX2175_CSM_MODE_LOAD_TO_BUFFER:
> > +	case MAX2175_CSM_MODE_PRESET_TUNE:
> > +	case MAX2175_CSM_MODE_SEARCH:
> > +	case MAX2175_CSM_MODE_AF_UPDATE:
> > +	case MAX2175_CSM_MODE_JUMP_FAST_TUNE:
> > +	case MAX2175_CSM_MODE_CHECK:
> > +	case MAX2175_CSM_MODE_LOAD_AND_SWAP:
> > +	case MAX2175_CSM_MODE_END:
> > +		ret = max2175_set_csm_mode(ctx, action);
> > +		break;
> > +	case MAX2175_CSM_MODE_BUFFER_PLUS_PRESET_TUNE:
> > +		ret = max2175_set_csm_mode(ctx, load_buffer);
> > +		if (ret) {
> > +			v4l2_err(ctx->client, "csm action %d load buf
> failed\n",
> > +				 action);
> > +			break;
> > +		}
> > +		ret = max2175_set_csm_mode(ctx, MAX2175_CSM_MODE_PRESET_TUNE);
> > +		break;
> > +	case MAX2175_CSM_MODE_BUFFER_PLUS_SEARCH:
> > +		ret = max2175_set_csm_mode(ctx, load_buffer);
> > +		if (ret) {
> > +			v4l2_err(ctx->client, "csm action %d load buf
> failed\n",
> > +				 action);
> > +			break;
> > +		}
> 
> Don't duplicate the error messages, move them after the switch statement.

Agreed. The error messages are not needed as the csm_mode function logs the mode argument in error log. Cleaned up.

> 
> > +		ret = max2175_set_csm_mode(ctx, MAX2175_CSM_MODE_SEARCH);
> > +		break;
> > +	case MAX2175_CSM_MODE_BUFFER_PLUS_AF_UPDATE:
> > +		ret = max2175_set_csm_mode(ctx, load_buffer);
> > +		if (ret) {
> > +			v4l2_err(ctx->client, "csm action %d load buf
> failed\n",
> > +				 action);
> > +			break;
> > +		}
> > +		ret = max2175_set_csm_mode(ctx, MAX2175_CSM_MODE_AF_UPDATE);
> > +		break;
> > +	case MAX2175_CSM_MODE_BUFFER_PLUS_JUMP_FAST_TUNE:
> 
> This function is only called with action set to
> MAX2175_CSM_MODE_BUFFER_PLUS_JUMP_FAST_TUNE. I'd remove the rest of the
> code for now, unless you have a plan to use it soon.

I'll remove. As mentioned earlier, I cannot tell how soon the other modes will be added. There are few other places with placeholders for other modes. I'll try to clean.

> 
> > +		ret = max2175_set_csm_mode(ctx, load_buffer);
> > +		if (ret) {
> > +			v4l2_err(ctx->client, "csm action %d load buf
> failed\n",
> > +				 action);
> > +			break;
> > +		}
> > +		ret = max2175_set_csm_mode(ctx,
> > +					   MAX2175_CSM_MODE_JUMP_FAST_TUNE);
> > +		break;
> > +	case MAX2175_CSM_MODE_BUFFER_PLUS_CHECK:
> > +		ret = max2175_set_csm_mode(ctx, load_buffer);
> > +		if (ret) {
> > +			v4l2_err(ctx->client, "csm action %d load buf
> failed\n",
> > +				 action);
> > +			break;
> > +		}
> > +		ret = max2175_set_csm_mode(ctx, MAX2175_CSM_MODE_CHECK);
> > +		break;
> > +	case MAX2175_CSM_MODE_BUFFER_PLUS_LOAD_AND_SWAP:
> > +		ret = max2175_set_csm_mode(ctx, load_buffer);
> > +		if (ret) {
> > +			v4l2_err(ctx->client, "csm action %d load buf
> failed\n",
> > +				 action);
> > +			break;
> > +		}
> > +		ret = max2175_set_csm_mode(ctx,
> MAX2175_CSM_MODE_LOAD_AND_SWAP);
> > +		break;
> > +	default:
> > +		ret = max2175_set_csm_mode(ctx, MAX2175_CSM_MODE_NO_ACTION);
> > +		break;
> > +	}
> > +	return ret;
> > +}
> > +
> > +static int max2175_set_lo_freq(struct max2175_ctx *ctx, u64 lo_freq)
> > +{
> > +	int ret;
> > +	u32 lo_mult;
> > +	u64 scaled_lo_freq;
> > +	const u64 scale_factor = 1000000ULL;
> > +	u64 scaled_npf, scaled_integer, scaled_fraction;
> > +	u32 frac_desired, int_desired;
> > +	u8 loband_bits, vcodiv_bits;
> 
> Do you really support frequencies above 4GHz ? 

Nope. 

If not most of the 64-bit
> values could be stored in 32 bits.

The 64bit variables are needed to extract the fractional part (upto 6 digit precision) out of floating point divisions (original user space code).

> 
> > +
> > +	scaled_lo_freq = lo_freq;
> > +	/* Scale to larger number for precision */
> > +	scaled_lo_freq = scaled_lo_freq * scale_factor * 100;
> > +
> > +	mxm_dbg(ctx, "scaled lo_freq %llu lo_freq %llu\n",
> > +		scaled_lo_freq, lo_freq);
> > +
> > +	if (MAX2175_IS_BAND_AM(ctx)) {
> > +		if (max2175_get_bit(ctx, 5, 7) == 0)
> > +			loband_bits = 0;
> > +			vcodiv_bits = 0;
> > +			lo_mult = 16;
> > +	} else if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_FM) {
> > +		if (lo_freq <= 74700000) {
> > +			loband_bits = 0;
> > +			vcodiv_bits = 0;
> > +			lo_mult = 16;
> > +		} else if ((lo_freq > 74700000) && (lo_freq <= 110000000)) {
> 
> No need for the inner parentheses.

Agreed.

> 
> > +			loband_bits = 1;
> > +			vcodiv_bits = 0;
> > +		} else {
> > +			loband_bits = 1;
> > +			vcodiv_bits = 3;
> > +		}
> > +		lo_mult = 8;
> > +	} else if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_VHF) {
> > +		if (lo_freq <= 210000000) {
> > +			loband_bits = 2;
> > +			vcodiv_bits = 2;
> > +		} else {
> > +			loband_bits = 2;
> > +			vcodiv_bits = 1;
> > +		}
> > +		lo_mult = 4;
> > +	} else {
> > +		loband_bits = 3;
> > +		vcodiv_bits = 2;
> > +		lo_mult = 2;
> > +	}
> > +
> > +	if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_L)
> > +		scaled_npf = (scaled_lo_freq / ctx->xtal_freq / lo_mult) /
> 100;
> > +	else
> > +		scaled_npf = (scaled_lo_freq / ctx->xtal_freq * lo_mult) /
> 100;
> > +
> > +	scaled_integer = scaled_npf / scale_factor * scale_factor;
> > +	int_desired = (u32)(scaled_npf / scale_factor);
> > +	scaled_fraction = scaled_npf - scaled_integer;
> > +	frac_desired = (u32)(scaled_fraction * 1048576 / scale_factor);
> > +
> > +	/* Check CSM is not busy */
> > +	ret = max2175_poll_csm_ready(ctx);
> > +	if (ret) {
> > +		v4l2_err(ctx->client, "lo_freq: csm busy. freq %llu\n",
> > +			 lo_freq);
> > +		return ret;
> > +	}
> > +
> > +	mxm_dbg(ctx, "loband %u vcodiv %u lo_mult %u scaled_npf %llu\n",
> > +		loband_bits, vcodiv_bits, lo_mult, scaled_npf);
> > +	mxm_dbg(ctx, "scaled int %llu frac %llu desired int %u frac %u\n",
> > +		scaled_integer, scaled_fraction, int_desired, frac_desired);
> > +
> > +	/* Write the calculated values to the appropriate registers */
> > +	max2175_set_bits(ctx, 5, 3, 2, loband_bits);
> > +	max2175_set_bits(ctx, 6, 7, 6, vcodiv_bits);
> > +	max2175_set_bits(ctx, 1, 7, 0, (u8)(int_desired & 0xff));
> > +	max2175_set_bits(ctx, 2, 3, 0, (u8)((frac_desired >> 16) & 0x1f));
> > +	max2175_set_bits(ctx, 3, 7, 0, (u8)((frac_desired >> 8) & 0xff));
> > +	max2175_set_bits(ctx, 4, 7, 0, (u8)(frac_desired & 0xff));
> > +	/* Flush the above registers to device */
> > +	max2175_flush_regstore(ctx, 1, 6);
> > +	return ret;
> > +}
> 
> [snip]
> 
> > +static int max2175_set_rf_freq_non_am_bands(struct max2175_ctx *ctx,
> > +u64
> > freq,
> > +					    u32 lo_pos)
> > +{
> > +	int ret;
> > +	s64 adj_freq;
> > +	u64 low_if_freq;
> > +
> > +	mxm_dbg(ctx, "rf_freq: non AM bands\n");
> > +
> > +	if (MAX2175_IS_FM_MODE(ctx))
> > +		low_if_freq = 128000;
> > +	else if (MAX2175_IS_FMHD_MODE(ctx))
> > +		low_if_freq = 228000;
> > +	else
> > +		return max2175_set_lo_freq(ctx, freq);
> > +
> > +	if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_VHF) {
> 
> You perform this check in multiple places, you could create a helper
> function.

Agreed.

> 
> > +		if (lo_pos == MAX2175_LO_ABOVE_DESIRED)
> > +			adj_freq = freq + low_if_freq;
> > +		else
> > +			adj_freq = freq - low_if_freq;
> > +	} else {
> > +		if (lo_pos == MAX2175_LO_ABOVE_DESIRED)
> > +			adj_freq = freq - low_if_freq;
> > +		else
> > +			adj_freq = freq + low_if_freq;
> > +	}
> 
> This could be written
> 
> 	if ((max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_VHF) ==
> 	    (lo_pos == MAX2175_LO_ABOVE_DESIRED))
> 		adj_freq = freq + low_if_freq;
> 	else
> 		adj_freq = freq - low_if_freq;
> 
> Same for the other similar constructs in the driver. Up to you.

Agreed. Nice :-)

> 
> > +
> > +	ret = max2175_set_lo_freq(ctx, adj_freq);
> > +	if (ret)
> > +		return ret;
> > +
> > +	return max2175_set_nco_freq(ctx, low_if_freq); }
> 
> [snip]
> 
> > +#define max2175_ctx_from_sd(x)	\
> > +	container_of(x, struct max2175_ctx, sd)
> > +#define max2175_ctx_from_ctrl(x)	\
> > +	container_of(x, struct max2175_ctx, ctrl_hdl)
> 
> I'd move it right after the structure definition, and turn them into
> static inline functions.

Agreed.

> 
> > +static int max2175_s_ctrl(struct v4l2_ctrl *ctrl) {
> > +	struct max2175_ctx *ctx = max2175_ctx_from_ctrl(ctrl->handler);
> > +	int ret = 0;
> > +
> > +	mxm_dbg(ctx, "s_ctrl: id 0x%x, val %u\n", ctrl->id, ctrl->val);
> > +	switch (ctrl->id) {
> > +	case V4L2_CID_MAX2175_I2S_EN:
> > +		max2175_i2s_enable(ctx, ctrl->val == 1);
> > +		break;
> > +	case V4L2_CID_MAX2175_I2S_MODE:
> > +		max2175_s_ctrl_i2s_mode(ctx, ctrl->val);
> > +		break;
> > +	case V4L2_CID_MAX2175_AM_HIZ:
> > +		v4l2_ctrl_activate(ctx->am_hiz, false);
> > +		break;
> > +	case V4L2_CID_MAX2175_HSLS:
> > +		v4l2_ctrl_activate(ctx->hsls, false);
> > +		break;
> > +	case V4L2_CID_MAX2175_RX_MODE:
> > +		mxm_dbg(ctx, "rx mode %u\n", ctrl->val);
> > +		max2175_s_ctrl_rx_mode(ctx, ctrl->val);
> > +		break;
> > +	default:
> > +		v4l2_err(ctx->client, "s:invalid ctrl id 0x%x\n", ctrl->id);
> > +		ret = -EINVAL;
> 
> This should never happen. The driver has too many error and debug messages
> overall.

Agreed :-). Will clean up.
 
> > +	}
> > +
> > +	return ret;
> > +}
> > +
> > +static int max2175_get_lna_gain(struct max2175_ctx *ctx) {
> > +	int gain = 0;
> > +	enum max2175_band band = max2175_get_bits(ctx, 5, 1, 0);
> > +
> > +	switch (band) {
> > +	case MAX2175_BAND_AM:
> > +		gain = max2175_read_bits(ctx, 51, 3, 1);
> > +		break;
> > +	case MAX2175_BAND_FM:
> > +		gain = max2175_read_bits(ctx, 50, 3, 1);
> > +		break;
> > +	case MAX2175_BAND_VHF:
> > +		gain = max2175_read_bits(ctx, 52, 3, 0);
> > +		break;
> > +	default:
> > +		v4l2_err(ctx->client, "invalid band %d to get rf gain\n",
> band);
> 
> Can this happen ?

Yes, there is "L-band". It is a paranoia check as I am testing by comparing logs sometimes :-(

> 
> > +		break;
> > +	}
> > +	return gain;
> > +}
> > +
> > +static int max2175_g_volatile_ctrl(struct v4l2_ctrl *ctrl)
> > +{
> > +	struct max2175_ctx *ctx = max2175_ctx_from_ctrl(ctrl->handler);
> > +
> > +	/* Only the dynamically changing values need to be in
> g_volatile_ctrl
> */
> > +	mxm_dbg(ctx, "g_volatile_ctrl: id 0x%x\n", ctrl->id);
> > +	switch (ctrl->id) {
> > +	case V4L2_CID_RF_TUNER_LNA_GAIN:
> > +		ctrl->val = max2175_get_lna_gain(ctx);
> > +		break;
> > +	case V4L2_CID_RF_TUNER_IF_GAIN:
> > +		ctrl->val = max2175_read_bits(ctx, 49, 4, 0);
> > +		break;
> > +	case V4L2_CID_RF_TUNER_PLL_LOCK:
> > +		ctrl->val = (max2175_read_bits(ctx, 60, 7, 6) == 3);
> > +		break;
> > +	default:
> > +		v4l2_err(ctx->client, "g:invalid ctrl id 0x%x\n", ctrl->id);
> 
> This should never happen either.

I agree.

> 
> > +		return -EINVAL;
> > +	}
> > +	mxm_dbg(ctx, "g_volatile_ctrl: id 0x%x val %d\n", ctrl->id, ctrl-
> >val);
> > +	return 0;
> > +};
> 
> [snip]
> 
> > +static const struct v4l2_ctrl_config max2175_i2s_en = {
> > +	.ops = &max2175_ctrl_ops,
> > +	.id = V4L2_CID_MAX2175_I2S_EN,
> 
> V4L2_CID_MAX2175_I2S_ENABLE ?

Agreed.

> 
> > +	.name = "I2S Enable",
> > +	.type = V4L2_CTRL_TYPE_BOOLEAN,
> > +	.min = 0,
> > +	.max = 1,
> > +	.step = 1,
> > +	.def = 1,
> > +};
> > +
> > +static const struct v4l2_ctrl_config max2175_i2s_mode = {
> > +	.ops = &max2175_ctrl_ops,
> > +	.id = V4L2_CID_MAX2175_I2S_MODE,
> > +	.name = "I2S_MODE value",
> > +	.type = V4L2_CTRL_TYPE_INTEGER,
> 
> Should this be a menu control ?

Hmm... the strings would be named "i2s mode x"? Will that be OK? 

> 
> > +	.min = 0,
> > +	.max = 4,
> > +	.step = 1,
> > +	.def = 0,
> > +};
> > +
> > +static const struct v4l2_ctrl_config max2175_am_hiz = {
> > +	.ops = &max2175_ctrl_ops,
> > +	.id = V4L2_CID_MAX2175_AM_HIZ,
> > +	.name = "AM High impedance input",
> > +	.type = V4L2_CTRL_TYPE_BOOLEAN,
> > +	.min = 0,
> > +	.max = 1,
> > +	.step = 1,
> > +	.def = 0,
> > +};
> > +
> > +static const struct v4l2_ctrl_config max2175_hsls = {
> > +	.ops = &max2175_ctrl_ops,
> > +	.id = V4L2_CID_MAX2175_HSLS,
> > +	.name = "HSLS above/below desired",
> > +	.type = V4L2_CTRL_TYPE_INTEGER,
> > +	.min = 0,
> > +	.max = 1,
> > +	.step = 1,
> > +	.def = 1,
> > +};
> > +
> > +
> > +/* NOTE: Any addition/deletion in the below list should be reflected in
> > + * max2175_modetag enum
> > + */
> > +static const char * const max2175_ctrl_eu_rx_mode_strings[] = {
> > +	"DAB 1.2",
> > +	"NULL",
> 
> Do you really mean "NULL", not NULL ?

Sorry, That's cut/paste from vivid-ctrl. I have cleaned it up with designated initializers as Geert pointed out.

> 
> > +};
> > +
> > +static const char * const max2175_ctrl_na_rx_mode_strings[] = {
> > +	"NA FM 1.0",
> > +	"NULL",
> > +};
> > +
> > +static const struct v4l2_ctrl_config max2175_eu_rx_mode = {
> > +	.ops = &max2175_ctrl_ops,
> > +	.id = V4L2_CID_MAX2175_RX_MODE,
> > +	.name = "RX MODE",
> > +	.type = V4L2_CTRL_TYPE_MENU,
> > +	.max = ARRAY_SIZE(max2175_ctrl_eu_rx_mode_strings) - 2,
> 
> If there's a single mode supported I'd skip adding those controls for now.

I'll try to add one more mode support if time permits. The menu looks much readable with v4l2-ctl & comparing the same with datasheet.

> 
> > +	.def = 0,
> > +	.qmenu = max2175_ctrl_eu_rx_mode_strings,
> > +};
> > +
> > +static const struct v4l2_ctrl_config max2175_na_rx_mode = {
> > +	.ops = &max2175_ctrl_ops,
> > +	.id = V4L2_CID_MAX2175_RX_MODE,
> > +	.name = "RX MODE",
> > +	.type = V4L2_CTRL_TYPE_MENU,
> > +	.max = ARRAY_SIZE(max2175_ctrl_na_rx_mode_strings) - 2,
> > +	.def = 0,
> > +	.qmenu = max2175_ctrl_na_rx_mode_strings,
> > +};
> > +
> > +static u32 max2175_refout_load_to_bits(struct i2c_client *client, u32
> load)
> > +{
> > +	u32 bits = 0;	/* REFOUT disabled */
> > +
> > +	if (load >= 0 && load <= 40)
> > +		bits = load / 10;
> > +	else if (load >= 60 && load <= 70)
> > +		bits = load / 10 - 1;
> > +	else
> > +		dev_warn(&client->dev, "invalid refout_load %u\n", load);
> 
> Your DT bindings specify 0 as a valid value.

Agreed. The DT values are changed to 10-70 range.

> 
> An invalid value specified in DT should be a fatal error.

OK. Will correct this.

> 
> > +
> > +	return bits;
> > +}
> > +
> > +static int max2175_probe(struct i2c_client *client,
> > +			const struct i2c_device_id *id)
> > +{
> > +	struct max2175_ctx *ctx;
> > +	struct device *dev = &client->dev;
> > +	struct v4l2_subdev *sd;
> > +	struct v4l2_ctrl_handler *hdl;
> > +	struct clk *clk;
> > +	bool master = true;
> > +	u32 refout_load, refout_bits = 0;	/* REFOUT disabled */
> > +	int ret;
> > +
> > +	/* Check if the adapter supports the needed features */
> > +	if (!i2c_check_functionality(client->adapter,
> > +				     I2C_FUNC_SMBUS_BYTE_DATA)) {
> > +		dev_err(&client->dev, "i2c check failed\n");
> > +		return -EIO;
> > +	}
> > +
> > +	if (of_find_property(client->dev.of_node, "maxim,slave", NULL))
> > +		master = false;
> > +
> > +	if (!of_property_read_u32(client->dev.of_node, "maxim,refout-load",
> > +				 &refout_load))
> > +		refout_bits = max2175_refout_load_to_bits(client,
> refout_load);
> > +
> > +	clk = devm_clk_get(&client->dev, "xtal");
> > +	if (IS_ERR(clk)) {
> > +		ret = PTR_ERR(clk);
> > +		dev_err(&client->dev, "cannot get xtal clock %d\n", ret);
> > +		return -ENODEV;
> > +	}
> > +
> > +	ctx = kzalloc(sizeof(struct max2175_ctx),
> 
> sizeof(*ctx)
> 
> > +			     GFP_KERNEL);
> 
> This fits on one line.

Yes, corrected in last cleanup.

> 
> > +	if (ctx == NULL)
> > +		return -ENOMEM;
> > +
> > +	sd = &ctx->sd;
> > +	ctx->master = master;
> > +	ctx->mode_resolved = false;
> > +
> > +	/* Set the defaults */
> > +	ctx->freq = bands_rf.rangelow;
> > +
> > +	ctx->xtal_freq = clk_get_rate(clk);
> > +	dev_info(&client->dev, "xtal freq %lluHz\n", ctx->xtal_freq);
> > +
> > +	v4l2_i2c_subdev_init(sd, client, &max2175_ops);
> > +	ctx->client = client;
> > +
> > +	sd->flags = V4L2_SUBDEV_FL_HAS_DEVNODE;
> > +	ctx->dev = dev;
> > +
> > +	/* Controls */
> > +	hdl = &ctx->ctrl_hdl;
> > +	ret = v4l2_ctrl_handler_init(hdl, 8);
> > +	if (ret) {
> > +		dev_err(&client->dev, "ctrl handler init failed\n");
> > +		goto err;
> > +	}
> > +
> > +	ctx->lna_gain = v4l2_ctrl_new_std(hdl, &max2175_ctrl_ops,
> > +					  V4L2_CID_RF_TUNER_LNA_GAIN,
> > +					  0, 15, 1, 2);
> > +	ctx->lna_gain->flags |= (V4L2_CTRL_FLAG_VOLATILE |
> > +				 V4L2_CTRL_FLAG_READ_ONLY);
> > +	ctx->if_gain = v4l2_ctrl_new_std(hdl, &max2175_ctrl_ops,
> > +					 V4L2_CID_RF_TUNER_IF_GAIN,
> > +					 0, 31, 1, 0);
> > +	ctx->if_gain->flags |= (V4L2_CTRL_FLAG_VOLATILE |
> > +				V4L2_CTRL_FLAG_READ_ONLY);
> > +	ctx->pll_lock = v4l2_ctrl_new_std(hdl, &max2175_ctrl_ops,
> > +					  V4L2_CID_RF_TUNER_PLL_LOCK,
> > +					  0, 1, 1, 0);
> > +	ctx->pll_lock->flags |= (V4L2_CTRL_FLAG_VOLATILE |
> > +				 V4L2_CTRL_FLAG_READ_ONLY);
> > +	ctx->i2s_en = v4l2_ctrl_new_custom(hdl, &max2175_i2s_en, NULL);
> > +	ctx->i2s_mode = v4l2_ctrl_new_custom(hdl, &max2175_i2s_mode, NULL);
> > +	ctx->am_hiz = v4l2_ctrl_new_custom(hdl, &max2175_am_hiz, NULL);
> > +	ctx->hsls = v4l2_ctrl_new_custom(hdl, &max2175_hsls, NULL);
> > +
> > +	if (ctx->xtal_freq == MAX2175_EU_XTAL_FREQ) {
> > +		ctx->rx_mode = v4l2_ctrl_new_custom(hdl,
> > +						    &max2175_eu_rx_mode,
> NULL);
> > +		ctx->rx_modes = (struct max2175_rxmode *)eu_rx_modes;
> > +	} else {
> > +		ctx->rx_mode = v4l2_ctrl_new_custom(hdl,
> > +						    &max2175_na_rx_mode,
> NULL);
> > +		ctx->rx_modes = (struct max2175_rxmode *)na_rx_modes;
> > +	}
> > +	ctx->sd.ctrl_handler = &ctx->ctrl_hdl;
> > +
> > +	ret = v4l2_async_register_subdev(sd);
> > +	if (ret) {
> > +		dev_err(&client->dev, "register subdev failed\n");
> > +		goto err_reg;
> > +	}
> > +	dev_info(&client->dev, "subdev registered\n");
> > +
> > +	/* Initialize device */
> > +	ret = max2175_core_init(ctx, refout_bits);
> > +	if (ret)
> > +		goto err_init;
> > +
> > +	mxm_dbg(ctx, "probed\n");
> > +	return 0;
> > +
> > +err_init:
> > +	v4l2_async_unregister_subdev(sd);
> > +err_reg:
> > +	v4l2_ctrl_handler_free(&ctx->ctrl_hdl);
> > +err:
> > +	kfree(ctx);
> > +	return ret;
> > +}
> > +
> > +static int max2175_remove(struct i2c_client *client)
> > +{
> > +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> > +	struct max2175_ctx *ctx = max2175_ctx_from_sd(sd);
> > +
> > +	v4l2_ctrl_handler_free(&ctx->ctrl_hdl);
> > +	v4l2_async_unregister_subdev(sd);
> > +	mxm_dbg(ctx, "removed\n");
> > +	kfree(ctx);
> > +	return 0;
> > +}
> > +
> > +static const struct i2c_device_id max2175_id[] = {
> > +	{ DRIVER_NAME, 0},
> > +	{},
> > +};
> > +
> 
> No need for a blank line here.

Agreed.

> 
> > +MODULE_DEVICE_TABLE(i2c, max2175_id);
> > +
> > +static const struct of_device_id max2175_of_ids[] = {
> > +	{ .compatible = "maxim, max2175", },
> > +	{ }
> > +};
> > +MODULE_DEVICE_TABLE(of, max2175_of_ids);
> > +
> > +static struct i2c_driver max2175_driver = {
> > +	.driver = {
> > +		.name	= DRIVER_NAME,
> > +		.of_match_table = max2175_of_ids,
> > +	},
> > +	.probe		= max2175_probe,
> > +	.remove		= max2175_remove,
> > +	.id_table	= max2175_id,
> > +};
> > +
> > +module_i2c_driver(max2175_driver);
> > +
> > +MODULE_DESCRIPTION("Maxim MAX2175 RF to Bits tuner driver");
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_AUTHOR("Ramesh Shanmugasundaram
> > <ramesh.shanmugasundaram@bp.renesas.com>"); diff --git
> > a/drivers/media/i2c/max2175/max2175.h
> b/drivers/media/i2c/max2175/max2175.h
> > new file mode 100644
> > index 0000000..61a508b
> > --- /dev/null
> > +++ b/drivers/media/i2c/max2175/max2175.h
> > @@ -0,0 +1,124 @@
> > +/*
> > + * Maxim Integrated MAX2175 RF to Bits tuner driver
> > + *
> > + * This driver & most of the hard coded values are based on the
> reference
> > + * application delivered by Maxim for this chip.
> > + *
> > + * Copyright (C) 2016 Maxim Integrated Products
> > + * Copyright (C) 2016 Renesas Electronics Corporation
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2
> > + * as published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> > + * GNU General Public License for more details.
> > + */
> > +
> > +#ifndef __MAX2175_H__
> > +#define __MAX2175_H__
> > +
> > +#include <linux/types.h>
> > +
> > +enum max2175_region {
> > +	MAX2175_REGION_EU = 0,	/* Europe */
> > +	MAX2175_REGION_NA,	/* North America */
> > +};
> > +
> > +#define MAX2175_EU_XTAL_FREQ	(36864000)	/* In Hz */
> > +#define MAX2175_NA_XTAL_FREQ	(40186125)	/* In Hz */
> > +
> > +enum max2175_band {
> > +	MAX2175_BAND_AM = 0,
> > +	MAX2175_BAND_FM,
> > +	MAX2175_BAND_VHF,
> > +	MAX2175_BAND_L,
> > +};
> > +
> > +/* NOTE: Any addition/deletion in the below enum should be reflected in
> > + * V4L2_CID_MAX2175_RX_MODE ctrl strings
> > + */
> > +enum max2175_modetag {
> > +	/* EU modes */
> > +	MAX2175_DAB_1_2 = 0,
> > +
> > +	/* Other possible modes to add in future
> > +	 * MAX2175_DAB_1_0,
> > +	 * MAX2175_DAB_1_3,
> > +	 * MAX2175_EU_FM_2_2,
> > +	 * MAX2175_EU_FM_1_0,
> > +	 * MAX2175_EU_FMHD_4_0,
> > +	 * MAX2175_EU_AM_1_0,
> > +	 * MAX2175_EU_AM_2_2,
> > +	 */
> > +
> > +	/* NA modes */
> > +	MAX2175_NA_FM_1_0 = 0,
> > +
> > +	/* Other possible modes to add in future
> > +	 * MAX2175_NA_FM_1_2,
> > +	 * MAX2175_NA_FMHD_1_0,
> > +	 * MAX2175_NA_FMHD_1_2,
> > +	 * MAX2175_NA_AM_1_0,
> > +	 * MAX2175_NA_AM_1_2,
> > +	 */
> > +};
> > +
> > +/* Supported I2S modes */
> > +enum {
> > +	MAX2175_I2S_MODE0 = 0,
> > +	MAX2175_I2S_MODE1,
> > +	MAX2175_I2S_MODE2,
> > +	MAX2175_I2S_MODE3,
> > +	MAX2175_I2S_MODE4,
> > +};
> > +
> > +/* Coefficient table groups */
> > +enum {
> > +	MAX2175_CH_MSEL = 0,
> > +	MAX2175_EQ_MSEL,
> > +	MAX2175_AA_MSEL,
> > +};
> > +
> > +/* HSLS LO injection polarity */
> > +enum {
> > +	MAX2175_LO_BELOW_DESIRED = 0,
> > +	MAX2175_LO_ABOVE_DESIRED,
> > +};
> > +
> > +/* Channel FSM modes */
> > +enum max2175_csm_mode {
> > +	MAX2175_CSM_MODE_LOAD_TO_BUFFER = 0,
> > +	MAX2175_CSM_MODE_PRESET_TUNE,
> > +	MAX2175_CSM_MODE_SEARCH,
> > +	MAX2175_CSM_MODE_AF_UPDATE,
> > +	MAX2175_CSM_MODE_JUMP_FAST_TUNE,
> > +	MAX2175_CSM_MODE_CHECK,
> > +	MAX2175_CSM_MODE_LOAD_AND_SWAP,
> > +	MAX2175_CSM_MODE_END,
> > +	MAX2175_CSM_MODE_BUFFER_PLUS_PRESET_TUNE,
> > +	MAX2175_CSM_MODE_BUFFER_PLUS_SEARCH,
> > +	MAX2175_CSM_MODE_BUFFER_PLUS_AF_UPDATE,
> > +	MAX2175_CSM_MODE_BUFFER_PLUS_JUMP_FAST_TUNE,
> > +	MAX2175_CSM_MODE_BUFFER_PLUS_CHECK,
> > +	MAX2175_CSM_MODE_BUFFER_PLUS_LOAD_AND_SWAP,
> > +	MAX2175_CSM_MODE_NO_ACTION
> > +};
> > +
> > +/* Rx mode */
> > +struct max2175_rxmode {
> > +	enum max2175_band band;		/* Associated band */
> > +	u32 freq;			/* Default freq in Hz */
> > +	u8 i2s_word_size;		/* Bit value */
> > +	u8 i2s_modes[4];		/* Supported modes */
> > +};
> > +
> > +/* Register map */
> > +struct max2175_regmap {
> > +	u8 idx;				/* Register index */
> > +	u8 val;				/* Register value */
> > +};
> 
> As no other file than max2175.c includes this, I would move at least the
> structure definitions to the .c file.

Agreed.

Thanks a lot for all the comments and suggestions. I'll post the next version soon.

Thanks,
Ramesh
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Laurent Pinchart Nov. 10, 2016, 8:46 a.m. UTC | #5
Hi Ramesh,

On Friday 21 Oct 2016 14:49:30 Ramesh Shanmugasundaram wrote:
> > On Wednesday 12 Oct 2016 15:10:25 Ramesh Shanmugasundaram wrote:
> >> This patch adds driver support for MAX2175 chip. This is Maxim
> >> Integrated's RF to Bits tuner front end chip designed for
> >> software-defined radio solutions. This driver exposes the tuner as a
> >> sub-device instance with standard and custom controls to configure the
> >> device.
> >>
> >> Signed-off-by: Ramesh Shanmugasundaram
> >> <ramesh.shanmugasundaram@bp.renesas.com> ---
> >> 
> >>  .../devicetree/bindings/media/i2c/max2175.txt      |   60 +
> >>  drivers/media/i2c/Kconfig                          |    4 +
> >>  drivers/media/i2c/Makefile                         |    2 +
> >>  drivers/media/i2c/max2175/Kconfig                  |    8 +
> >>  drivers/media/i2c/max2175/Makefile                 |    4 +
> >>  drivers/media/i2c/max2175/max2175.c                | 1624 +++++++++++++
> >>  drivers/media/i2c/max2175/max2175.h                |  124 ++
> >>  7 files changed, 1826 insertions(+)
> >>  create mode 100644
> >> Documentation/devicetree/bindings/media/i2c/max2175.txt
> >>  create mode 100644 drivers/media/i2c/max2175/Kconfig  create mode
> >> 100644 drivers/media/i2c/max2175/Makefile
> >>  create mode 100644 drivers/media/i2c/max2175/max2175.c
> >>  create mode 100644 drivers/media/i2c/max2175/max2175.h
> >> 
> >> diff --git a/Documentation/devicetree/bindings/media/i2c/max2175.txt
> >> b/Documentation/devicetree/bindings/media/i2c/max2175.txt new file
> >> mode 100644
> >> index 0000000..2250d5f
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/media/i2c/max2175.txt
> >> @@ -0,0 +1,60 @@

[snip]

> >> +Optional properties:
> >> +--------------------
> >> +- maxim,slave	   : empty property indicates this is a slave of
> >> another
> >> +		     master tuner. This is used to define two tuners in
> >> +		     diversity mode (1 master, 1 slave). By default each
> >> +		     tuner is an individual master.
> > 
> > Would it be useful to make that property a phandle to the master tuner, to
> > give drivers a way to access the master ? I haven't checked whether there
> > could be use cases for that.
> 
> As of now, I cannot find any use case for it from the datasheet. In future,
> we could add if such need arise.

My point is that making the maxim,slave property a phandle now would allow 
handling such future cases without any change to the DT bindings.

[snip]

> > > diff --git a/drivers/media/i2c/max2175/max2175.c
> > > b/drivers/media/i2c/max2175/max2175.c new file mode 100644 index
> > > 0000000..71b60c2
> > > --- /dev/null
> > > +++ b/drivers/media/i2c/max2175/max2175.c

[snip]

> > > +static int max2175_poll_csm_ready(struct max2175_ctx *ctx) {
> > > +	return max2175_poll_timeout(ctx, 69, 1, 1, 0, 50);
> > 
> > Please define macros for register addresses and values, this is just
> > unreadable.
> 
> The Tuner provider is unwilling to disclose all register details. I agree on
> the readability issue with this restriction but this is somewhat true for
> some sensitive IPs in the media subsystem.

Is it the case that you don't have access to the information, or that you have 
been forbidden to disclose them by the tuner manufacturer ?

> > > +}

[snip]

> > > +static int max2175_set_lo_freq(struct max2175_ctx *ctx, u64 lo_freq)
> > > +{
> > > +	int ret;
> > > +	u32 lo_mult;
> > > +	u64 scaled_lo_freq;
> > > +	const u64 scale_factor = 1000000ULL;
> > > +	u64 scaled_npf, scaled_integer, scaled_fraction;
> > > +	u32 frac_desired, int_desired;
> > > +	u8 loband_bits, vcodiv_bits;
> > 
> > Do you really support frequencies above 4GHz ?
> 
> Nope.
> 
> If not most of the 64-bit
> 
> > values could be stored in 32 bits.
> 
> The 64bit variables are needed to extract the fractional part (upto 6 digit
> precision) out of floating point divisions (original user space code).

OK. The code would be more efficient if you made the scaling factor a power of 
two though. 1048576 could be a good value.

> >> +
> >> +	scaled_lo_freq = lo_freq;
> >> +	/* Scale to larger number for precision */
> >> +	scaled_lo_freq = scaled_lo_freq * scale_factor * 100;

I just noticed that you could write the two lines as

	scaled_lo_freq = lo_freq * scale_factor * 100;

By the way, why do you multiply by 100 here, and...

> >> +	mxm_dbg(ctx, "scaled lo_freq %llu lo_freq %llu\n",
> >> +		scaled_lo_freq, lo_freq);
> >> +
> >> +	if (MAX2175_IS_BAND_AM(ctx)) {
> >> +		if (max2175_get_bit(ctx, 5, 7) == 0)
> >> +			loband_bits = 0;
> >> +			vcodiv_bits = 0;
> >> +			lo_mult = 16;
> >> +	} else if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_FM) {
> >> +		if (lo_freq <= 74700000) {
> >> +			loband_bits = 0;
> >> +			vcodiv_bits = 0;
> >> +			lo_mult = 16;
> >> +		} else if ((lo_freq > 74700000) && (lo_freq <= 110000000)) {
> > 
> > No need for the inner parentheses.
> 
> Agreed.
> 
> >> +			loband_bits = 1;
> >> +			vcodiv_bits = 0;
> >> +		} else {
> >> +			loband_bits = 1;
> >> +			vcodiv_bits = 3;
> >> +		}
> >> +		lo_mult = 8;
> >> +	} else if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_VHF) {
> >> +		if (lo_freq <= 210000000) {
> >> +			loband_bits = 2;
> >> +			vcodiv_bits = 2;
> >> +		} else {
> >> +			loband_bits = 2;
> >> +			vcodiv_bits = 1;
> >> +		}
> >> +		lo_mult = 4;
> >> +	} else {
> >> +		loband_bits = 3;
> >> +		vcodiv_bits = 2;
> >> +		lo_mult = 2;
> >> +	}
> >> +
> >> +	if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_L)
> >> +		scaled_npf = (scaled_lo_freq / ctx->xtal_freq / lo_mult) /
> >> 100;
> >> +	else
> >> +		scaled_npf = (scaled_lo_freq / ctx->xtal_freq * lo_mult) /
> >> 100;

... divide by 100 here without using the value in-between nor after ?

> >> +
> >> +	scaled_integer = scaled_npf / scale_factor * scale_factor;
> >> +	int_desired = (u32)(scaled_npf / scale_factor);
> >> +	scaled_fraction = scaled_npf - scaled_integer;
> >> +	frac_desired = (u32)(scaled_fraction * 1048576 / scale_factor);
> >> +
> >> +	/* Check CSM is not busy */
> >> +	ret = max2175_poll_csm_ready(ctx);
> >> +	if (ret) {
> >> +		v4l2_err(ctx->client, "lo_freq: csm busy. freq %llu\n",
> >> +			 lo_freq);
> >> +		return ret;
> >> +	}
> >> +
> >> +	mxm_dbg(ctx, "loband %u vcodiv %u lo_mult %u scaled_npf %llu\n",
> >> +		loband_bits, vcodiv_bits, lo_mult, scaled_npf);
> >> +	mxm_dbg(ctx, "scaled int %llu frac %llu desired int %u frac %u\n",
> >> +		scaled_integer, scaled_fraction, int_desired, frac_desired);
> >> +
> >> +	/* Write the calculated values to the appropriate registers */
> >> +	max2175_set_bits(ctx, 5, 3, 2, loband_bits);
> >> +	max2175_set_bits(ctx, 6, 7, 6, vcodiv_bits);
> >> +	max2175_set_bits(ctx, 1, 7, 0, (u8)(int_desired & 0xff));
> >> +	max2175_set_bits(ctx, 2, 3, 0, (u8)((frac_desired >> 16) & 0x1f));
> >> +	max2175_set_bits(ctx, 3, 7, 0, (u8)((frac_desired >> 8) & 0xff));
> >> +	max2175_set_bits(ctx, 4, 7, 0, (u8)(frac_desired & 0xff));
> >> +	/* Flush the above registers to device */
> >> +	max2175_flush_regstore(ctx, 1, 6);
> >> +	return ret;
> >> +}

[snip]

> >> +static int max2175_get_lna_gain(struct max2175_ctx *ctx) {
> >> +	int gain = 0;
> >> +	enum max2175_band band = max2175_get_bits(ctx, 5, 1, 0);
> >> +
> >> +	switch (band) {
> >> +	case MAX2175_BAND_AM:
> >> +		gain = max2175_read_bits(ctx, 51, 3, 1);
> >> +		break;
> >> +	case MAX2175_BAND_FM:
> >> +		gain = max2175_read_bits(ctx, 50, 3, 1);
> >> +		break;
> >> +	case MAX2175_BAND_VHF:
> >> +		gain = max2175_read_bits(ctx, 52, 3, 0);
> >> +		break;
> >> +	default:
> >> +		v4l2_err(ctx->client, "invalid band %d to get rf gain\n",
> >> band);
> > 
> > Can this happen ?
> 
> Yes, there is "L-band". It is a paranoia check as I am testing by comparing
> logs sometimes :-(

OK. By the way, you could get rid of the gain variable by returning directly 
in the case statements.

> >> +		break;
> >> +	}
> >> +	return gain;
> >> +}

[snip]

> >> +static const struct v4l2_ctrl_config max2175_i2s_mode = {
> >> +	.ops = &max2175_ctrl_ops,
> >> +	.id = V4L2_CID_MAX2175_I2S_MODE,
> >> +	.name = "I2S_MODE value",
> >> +	.type = V4L2_CTRL_TYPE_INTEGER,
> > 
> > Should this be a menu control ?
> 
> Hmm... the strings would be named "i2s mode x"? Will that be OK?

How about describing the modes instead ? Are they standardized ?

> >> +	.min = 0,
> >> +	.max = 4,
> >> +	.step = 1,
> >> +	.def = 0,
> >> +};

[snip]
  

Patch

diff --git a/Documentation/devicetree/bindings/media/i2c/max2175.txt b/Documentation/devicetree/bindings/media/i2c/max2175.txt
new file mode 100644
index 0000000..2250d5f
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/i2c/max2175.txt
@@ -0,0 +1,60 @@ 
+Maxim Integrated MAX2175 RF to Bits tuner
+-----------------------------------------
+
+The MAX2175 IC is an advanced analog/digital hybrid-radio receiver with
+RF to BitsĀ® front-end designed for software-defined radio solutions.
+
+Required properties:
+--------------------
+- compatible: "maxim,max2175" for MAX2175 RF-to-bits tuner.
+- clocks: phandle to the fixed xtal clock.
+- clock-names: name of the fixed xtal clock.
+- port: video interface child port node of a tuner that defines the local
+  and remote endpoints. The remote endpoint is assumed to be an SDR device
+  that is capable of receiving the digital samples from the tuner.
+
+Optional properties:
+--------------------
+- maxim,slave	   : empty property indicates this is a slave of another
+		     master tuner. This is used to define two tuners in
+		     diversity mode (1 master, 1 slave). By default each
+		     tuner is an individual master.
+- maxim,refout-load: load capacitance value (in pF) on reference output
+		     drive level. The mapping of these load values to
+		     respective bit values are given below.
+		     0 - Reference output disabled
+		     1 - 10pF load
+		     2 - 20pF load
+		     3 - 30pF load
+		     4 - 40pF load
+		     5 - 60pF load
+		     6 - 70pF load
+
+Example:
+--------
+
+Board specific DTS file
+
+/* Fixed XTAL clock node */
+maxim_xtal: maximextal {
+	compatible = "fixed-clock";
+	#clock-cells = <0>;
+	clock-frequency = <36864000>;
+};
+
+/* A tuner device instance under i2c bus */
+max2175_0: tuner@60 {
+	#clock-cells = <0>;
+	compatible = "maxim,max2175";
+	reg = <0x60>;
+	clocks = <&maxim_xtal>;
+	clock-names = "xtal";
+	maxim,refout-load = <10>;
+
+	port {
+		max2175_0_ep: endpoint {
+			remote-endpoint = <&slave_rx_v4l2_sdr_device>;
+		};
+	};
+
+};
diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
index 2669b4b..66c73b0 100644
--- a/drivers/media/i2c/Kconfig
+++ b/drivers/media/i2c/Kconfig
@@ -749,6 +749,10 @@  config VIDEO_SAA6752HS
 	  To compile this driver as a module, choose M here: the
 	  module will be called saa6752hs.
 
+comment "SDR tuner chips"
+
+source "drivers/media/i2c/max2175/Kconfig"
+
 comment "Miscellaneous helper chips"
 
 config VIDEO_THS7303
diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
index 92773b2..cfae721 100644
--- a/drivers/media/i2c/Makefile
+++ b/drivers/media/i2c/Makefile
@@ -6,6 +6,8 @@  obj-$(CONFIG_VIDEO_CX25840) += cx25840/
 obj-$(CONFIG_VIDEO_M5MOLS)	+= m5mols/
 obj-y				+= soc_camera/
 
+obj-$(CONFIG_SDR_MAX2175) 	+= max2175/
+
 obj-$(CONFIG_VIDEO_APTINA_PLL) += aptina-pll.o
 obj-$(CONFIG_VIDEO_TVAUDIO) += tvaudio.o
 obj-$(CONFIG_VIDEO_TDA7432) += tda7432.o
diff --git a/drivers/media/i2c/max2175/Kconfig b/drivers/media/i2c/max2175/Kconfig
new file mode 100644
index 0000000..a8a0664
--- /dev/null
+++ b/drivers/media/i2c/max2175/Kconfig
@@ -0,0 +1,8 @@ 
+config SDR_MAX2175
+	tristate "Maxim 2175 RF to Bits tuner"
+	depends on VIDEO_V4L2 && MEDIA_SDR_SUPPORT && I2C && VIDEO_V4L2_SUBDEV_API
+	---help---
+	  Support for Maxim 2175 tuner
+
+	  To compile this driver as a module, choose M here; the
+	  module will be called max2175.
diff --git a/drivers/media/i2c/max2175/Makefile b/drivers/media/i2c/max2175/Makefile
new file mode 100644
index 0000000..9bb46ac
--- /dev/null
+++ b/drivers/media/i2c/max2175/Makefile
@@ -0,0 +1,4 @@ 
+#
+# Makefile for Maxim RF to Bits tuner device
+#
+obj-$(CONFIG_SDR_MAX2175) += max2175.o
diff --git a/drivers/media/i2c/max2175/max2175.c b/drivers/media/i2c/max2175/max2175.c
new file mode 100644
index 0000000..71b60c2
--- /dev/null
+++ b/drivers/media/i2c/max2175/max2175.c
@@ -0,0 +1,1624 @@ 
+/*
+ * Maxim Integrated MAX2175 RF to Bits tuner driver
+ *
+ * This driver & most of the hard coded values are based on the reference
+ * application delivered by Maxim for this chip.
+ *
+ * Copyright (C) 2016 Maxim Integrated Products
+ * Copyright (C) 2016 Renesas Electronics Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-of.h>
+
+#include "max2175.h"
+
+#define DRIVER_NAME "max2175"
+
+static unsigned int max2175_debug;
+module_param(max2175_debug, uint, 0644);
+MODULE_PARM_DESC(max2175_debug, "activate debug info");
+
+#define mxm_dbg(ctx, fmt, arg...) \
+	v4l2_dbg(1, max2175_debug, &ctx->sd, fmt, ## arg)
+
+/* NOTE: Any addition/deletion in the below list should be reflected in
+ * max2175_modetag enum
+ */
+static const struct max2175_rxmode eu_rx_modes[] = { /* Indexed by EU modetag */
+	/* EU modes */
+	{ MAX2175_BAND_VHF, 182640000, 0, { 0, 0, 0, 0 } },
+};
+
+static const struct max2175_rxmode na_rx_modes[] = { /* Indexed by NA modetag */
+	/* NA modes */
+	{ MAX2175_BAND_FM, 98255520, 1, { 0, 0, 0, 0 } },
+};
+
+/* Preset values:
+ * Based on Maxim MAX2175 Register Table revision: 130p10
+ */
+static const u8 full_fm_eu_1p0[] = {
+	0x15, 0x04, 0xb8, 0xe3, 0x35, 0x18, 0x7c, 0x00,
+	0x00, 0x7d, 0x40, 0x08, 0x70, 0x7a, 0x88, 0x91,
+	0x61, 0x61, 0x61, 0x61, 0x5a, 0x0f, 0x34, 0x1c,
+	0x14, 0x88, 0x33, 0x02, 0x00, 0x09, 0x00, 0x65,
+	0x9f, 0x2b, 0x80, 0x00, 0x95, 0x05, 0x2c, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x40,
+	0x4a, 0x08, 0xa8, 0x0e, 0x0e, 0x2f, 0x7e, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0xab, 0x5e, 0xa9,
+	0xae, 0xbb, 0x57, 0x18, 0x3b, 0x03, 0x3b, 0x64,
+	0x40, 0x60, 0x00, 0x2a, 0xbf, 0x3f, 0xff, 0x9f,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0a, 0x00,
+	0xff, 0xfc, 0xef, 0x1c, 0x40, 0x00, 0x00, 0x02,
+	0x00, 0x00, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0xac, 0x40, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x75, 0x00, 0x00,
+	0x00, 0x47, 0x00, 0x00, 0x11, 0x3f, 0x22, 0x00,
+	0xf1, 0x00, 0x41, 0x03, 0xb0, 0x00, 0x00, 0x00,
+	0x1b,
+};
+
+static const u8 full_fm_na_1p0[] = {
+	0x13, 0x08, 0x8d, 0xc0, 0x35, 0x18, 0x7d, 0x3f,
+	0x7d, 0x75, 0x40, 0x08, 0x70, 0x7a, 0x88, 0x91,
+	0x61, 0x61, 0x61, 0x61, 0x5c, 0x0f, 0x34, 0x1c,
+	0x14, 0x88, 0x33, 0x02, 0x00, 0x01, 0x00, 0x65,
+	0x9f, 0x2b, 0x80, 0x00, 0x95, 0x05, 0x2c, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x40,
+	0x4a, 0x08, 0xa8, 0x0e, 0x0e, 0xaf, 0x7e, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0xab, 0x5e, 0xa9,
+	0xae, 0xbb, 0x57, 0x18, 0x3b, 0x03, 0x3b, 0x64,
+	0x40, 0x60, 0x00, 0x2a, 0xbf, 0x3f, 0xff, 0x9f,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0a, 0x00,
+	0xff, 0xfc, 0xef, 0x1c, 0x40, 0x00, 0x00, 0x02,
+	0x00, 0x00, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0xa6, 0x40, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x75, 0x00, 0x00,
+	0x00, 0x35, 0x00, 0x00, 0x11, 0x3f, 0x22, 0x00,
+	0xf1, 0x00, 0x41, 0x03, 0xb0, 0x00, 0x00, 0x00,
+	0x1b,
+};
+
+static const struct max2175_regmap dab12_map[] = {
+	{ 0x01, 0x13 }, { 0x02, 0x0d }, { 0x03, 0x15 }, { 0x04, 0x55 },
+	{ 0x05, 0x0a }, { 0x06, 0xa0 }, { 0x07, 0x40 }, { 0x08, 0x00 },
+	{ 0x09, 0x00 }, { 0x0a, 0x7d }, { 0x0b, 0x4a }, { 0x0c, 0x28 },
+	{ 0x0e, 0x43 }, { 0x0f, 0xb5 }, { 0x10, 0x31 }, { 0x11, 0x9e },
+	{ 0x12, 0x68 }, { 0x13, 0x9e }, { 0x14, 0x68 }, { 0x15, 0x58 },
+	{ 0x16, 0x2f }, { 0x17, 0x3f }, { 0x18, 0x40 }, { 0x1a, 0x88 },
+	{ 0x1b, 0xaa }, { 0x1c, 0x9a }, { 0x1d, 0x00 }, { 0x1e, 0x00 },
+	{ 0x23, 0x80 }, { 0x24, 0x00 }, { 0x25, 0x00 }, { 0x26, 0x00 },
+	{ 0x27, 0x00 }, { 0x32, 0x08 }, { 0x33, 0xf8 }, { 0x36, 0x2d },
+	{ 0x37, 0x7e }, { 0x55, 0xaf }, { 0x56, 0x3f }, { 0x57, 0xf8 },
+	{ 0x58, 0x99 }, { 0x76, 0x00 }, { 0x77, 0x00 }, { 0x78, 0x02 },
+	{ 0x79, 0x40 }, { 0x82, 0x00 }, { 0x83, 0x00 }, { 0x85, 0x00 },
+	{ 0x86, 0x20 },
+};
+
+static const u16 ch_coeff_dab1[] = {
+	0x001c, 0x0007, 0xffcd, 0x0056, 0xffa4, 0x0033, 0x0027, 0xff61,
+	0x010e, 0xfec0, 0x0106, 0xffb8, 0xff1c, 0x023c, 0xfcb2, 0x039b,
+	0xfd4e, 0x0055, 0x036a, 0xf7de, 0x0d21, 0xee72, 0x1499, 0x6a51,
+};
+
+static const u16 ch_coeff_fmeu[] = {
+	0x0000, 0xffff, 0x0001, 0x0002, 0xfffa, 0xffff, 0x0015, 0xffec,
+	0xffde, 0x0054, 0xfff9, 0xff52, 0x00b8, 0x00a2, 0xfe0a, 0x00af,
+	0x02e3, 0xfc14, 0xfe89, 0x089d, 0xfa2e, 0xf30f, 0x25be, 0x4eb6,
+};
+
+static const u16 eq_coeff_fmeu1_ra02_m6db[] = {
+	0x0040, 0xffc6, 0xfffa, 0x002c, 0x000d, 0xff90, 0x0037, 0x006e,
+	0xffc0, 0xff5b, 0x006a, 0x00f0, 0xff57, 0xfe94, 0x0112, 0x0252,
+	0xfe0c, 0xfc6a, 0x0385, 0x0553, 0xfa49, 0xf789, 0x0b91, 0x1a10,
+};
+
+static const u16 ch_coeff_fmna[] = {
+	0x0001, 0x0003, 0xfffe, 0xfff4, 0x0000, 0x001f, 0x000c, 0xffbc,
+	0xffd3, 0x007d, 0x0075, 0xff33, 0xff01, 0x0131, 0x01ef, 0xfe60,
+	0xfc7a, 0x020e, 0x0656, 0xfd94, 0xf395, 0x02ab, 0x2857, 0x3d3f,
+};
+
+static const u16 eq_coeff_fmna1_ra02_m6db[] = {
+	0xfff1, 0xffe1, 0xffef, 0x000e, 0x0030, 0x002f, 0xfff6, 0xffa7,
+	0xff9d, 0x000a, 0x00a2, 0x00b5, 0xffea, 0xfed9, 0xfec5, 0x003d,
+	0x0217, 0x021b, 0xff5a, 0xfc2b, 0xfcbd, 0x02c4, 0x0ac3, 0x0e85,
+};
+
+static const u8 adc_presets[2][23] = {
+	{
+		0x83, 0x00, 0xCF, 0xB4, 0x0F, 0x2C, 0x0C, 0x49,
+		0x00, 0x00, 0x00, 0x8C,	0x02, 0x02, 0x00, 0x04,
+		0xEC, 0x82, 0x4B, 0xCC, 0x01, 0x88, 0x0C,
+	},
+	{
+		0x83, 0x00, 0xCF, 0xB4,	0x0F, 0x2C, 0x0C, 0x49,
+		0x00, 0x00, 0x00, 0x8C,	0x02, 0x20, 0x33, 0x8C,
+		0x57, 0xD7, 0x59, 0xB7,	0x65, 0x0E, 0x0C,
+	},
+};
+
+/* Custom controls */
+#define V4L2_CID_MAX2175_I2S_EN		(V4L2_CID_USER_MAX217X_BASE + 0x01)
+#define V4L2_CID_MAX2175_I2S_MODE	(V4L2_CID_USER_MAX217X_BASE + 0x02)
+#define V4L2_CID_MAX2175_AM_HIZ		(V4L2_CID_USER_MAX217X_BASE + 0x03)
+#define V4L2_CID_MAX2175_HSLS		(V4L2_CID_USER_MAX217X_BASE + 0x04)
+#define V4L2_CID_MAX2175_RX_MODE	(V4L2_CID_USER_MAX217X_BASE + 0x05)
+
+/* Tuner bands */
+static const struct v4l2_frequency_band bands_rf = {
+	.tuner = 0,
+	.type = V4L2_TUNER_RF,
+	.index = 0,
+	.capability = V4L2_TUNER_CAP_1HZ | V4L2_TUNER_CAP_FREQ_BANDS,
+	.rangelow   = 160000000,
+	.rangehigh  = 240000000,
+};
+
+struct max2175_ctx {
+	struct v4l2_subdev sd;
+	struct i2c_client *client;
+	struct device *dev;
+
+	/* Cached configuration */
+	u8 regs[256];
+	enum max2175_modetag mode;	/* Receive mode tag */
+	u32 freq;			/* In Hz */
+	struct max2175_rxmode *rx_modes;
+
+	/* Device settings */
+	bool master;
+	u32 decim_ratio;
+	u64 xtal_freq;
+
+	/* ROM values */
+	u8 rom_bbf_bw_am;
+	u8 rom_bbf_bw_fm;
+	u8 rom_bbf_bw_dab;
+
+	/* Local copy of old settings */
+	u8 i2s_test;
+
+	u8 nbd_gain;
+	u8 nbd_threshold;
+	u8 wbd_gain;
+	u8 wbd_threshold;
+	u8 bbd_threshold;
+	u8 bbdclip_threshold;
+	u8 lt_wbd_threshold;
+	u8 lt_wbd_gain;
+
+	/* Controls */
+	struct v4l2_ctrl_handler ctrl_hdl;
+	struct v4l2_ctrl *lna_gain;	/* LNA gain value */
+	struct v4l2_ctrl *if_gain;	/* I/F gain value */
+	struct v4l2_ctrl *pll_lock;	/* PLL lock */
+	struct v4l2_ctrl *i2s_en;	/* I2S output enable */
+	struct v4l2_ctrl *i2s_mode;	/* I2S mode value */
+	struct v4l2_ctrl *am_hiz;	/* AM High impledance input */
+	struct v4l2_ctrl *hsls;		/* High-side/Low-side polarity */
+	struct v4l2_ctrl *rx_mode;	/* Receive mode */
+
+	/* Driver private variables */
+	bool mode_resolved;		/* Flag to sanity check settings */
+};
+
+/* Helpers */
+
+static int max2175_reg_write(struct max2175_ctx *ctx, u8 idx, u8 val)
+{
+	int ret;
+
+	ret = i2c_smbus_write_byte_data(ctx->client, idx, val);
+	if (ret) {
+		v4l2_err(ctx->client,
+			 "write: idx 0x%02x, val 0x%02x\n", idx, val);
+		return ret;
+	}
+
+	/* Update local store */
+	ctx->regs[idx] = val;
+	if (max2175_debug >= 2)
+		mxm_dbg(ctx, "write: reg[0x%02x] = 0x%02x\n", idx, val);
+
+	return ret;
+}
+
+static int max2175_reg_read(struct max2175_ctx *ctx, u8 idx)
+{
+	int ret;
+
+	ret = i2c_smbus_read_byte_data(ctx->client, idx);
+	if (ret < 0) {
+		v4l2_err(ctx->client, "read: idx 0x%02x\n", idx);
+		return ret;
+	}
+
+	if (max2175_debug >= 2)
+		mxm_dbg(ctx, "read: reg[0x%02x] = 0x%02x\n", idx, ret);
+
+	return ret;
+}
+
+/* Flush local copy to device from idx to idx+len (inclusive) */
+static void max2175_flush_regstore(struct max2175_ctx *ctx, u8 idx, u8 len)
+{
+	u8 i;
+
+	for (i = idx; i <= len; i++)
+		max2175_reg_write(ctx, i, ctx->regs[i]);
+}
+
+/* General bitops helpers */
+static inline u8  __max2175_get_bits(u8 val, u8 msb, u8 lsb)
+{
+	return ((val & GENMASK(msb, lsb)) >> lsb);
+}
+
+static inline u8  __max2175_set_bits(u8 val, u8 msb, u8 lsb, u8 newval)
+{
+	u8 mask = GENMASK(msb, lsb);
+
+	return ((val & ~mask) | ((newval << lsb) & mask));
+}
+
+/* Local store bitops helpers */
+static u8 max2175_get_bits(struct max2175_ctx *ctx, u8 idx, u8 msb, u8 lsb)
+{
+	if (max2175_debug >= 2)
+		mxm_dbg(ctx, "get_bits: idx:%u msb:%u lsb:%u\n",
+			idx, msb, lsb);
+	return __max2175_get_bits(ctx->regs[idx], msb, lsb);
+}
+
+static bool max2175_get_bit(struct max2175_ctx *ctx, u8 idx, u8 bit)
+{
+	return !!max2175_get_bits(ctx, idx, bit, bit);
+}
+
+static void max2175_set_bits(struct max2175_ctx *ctx, u8 idx,
+		      u8 msb, u8 lsb, u8 newval)
+{
+	if (max2175_debug >= 2)
+		mxm_dbg(ctx, "set_bits: idx:%u msb:%u lsb:%u newval:%u\n",
+			idx, msb, lsb, newval);
+	ctx->regs[idx] = __max2175_set_bits(ctx->regs[idx], msb, lsb,
+					      newval);
+}
+
+static void max2175_set_bit(struct max2175_ctx *ctx, u8 idx, u8 bit, u8 newval)
+{
+	max2175_set_bits(ctx, idx, bit, bit, newval);
+}
+
+/* Device register bitops helpers */
+static u8 max2175_read_bits(struct max2175_ctx *ctx, u8 idx, u8 msb, u8 lsb)
+{
+	return __max2175_get_bits(max2175_reg_read(ctx, idx), msb, lsb);
+}
+
+static void max2175_write_bits(struct max2175_ctx *ctx, u8 idx, u8 msb,
+			u8 lsb, u8 newval)
+{
+	/* Update local copy & write to device */
+	max2175_set_bits(ctx, idx, msb, lsb, newval);
+	max2175_reg_write(ctx, idx, ctx->regs[idx]);
+}
+
+static void max2175_write_bit(struct max2175_ctx *ctx, u8 idx, u8 bit,
+			      u8 newval)
+{
+	if (max2175_debug >= 2)
+		mxm_dbg(ctx, "idx %u, bit %u, newval %u\n", idx, bit, newval);
+	max2175_write_bits(ctx, idx, bit, bit, newval);
+}
+
+static int max2175_poll_timeout(struct max2175_ctx *ctx, u8 idx, u8 msb, u8 lsb,
+				u8 exp_val, u32 timeout)
+{
+	unsigned long end = jiffies + msecs_to_jiffies(timeout);
+	int ret;
+
+	do {
+		ret = max2175_read_bits(ctx, idx, msb, lsb);
+		if (ret < 0)
+			return ret;
+		if (ret == exp_val)
+			return 0;
+
+		usleep_range(1000, 1500);
+	} while (time_is_after_jiffies(end));
+
+	return -EBUSY;
+}
+
+static int max2175_poll_csm_ready(struct max2175_ctx *ctx)
+{
+	return max2175_poll_timeout(ctx, 69, 1, 1, 0, 50);
+}
+
+#define MAX2175_IS_BAND_AM(ctx)		\
+	(max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_AM)
+
+#define MAX2175_IS_FM_MODE(ctx)		\
+	(max2175_get_bits(ctx, 12, 5, 4) == 0)
+
+#define MAX2175_IS_FMHD_MODE(ctx)	\
+	(max2175_get_bits(ctx, 12, 5, 4) == 1)
+
+#define MAX2175_IS_DAB_MODE(ctx)	\
+	(max2175_get_bits(ctx, 12, 5, 4) == 2)
+
+static int max2175_band_from_freq(u64 freq)
+{
+	if (freq >= 144000 && freq <= 26100000)
+		return MAX2175_BAND_AM;
+	else if (freq >= 65000000 && freq <= 108000000)
+		return MAX2175_BAND_FM;
+	else if (freq >= 160000000 && freq <= 240000000)
+		return MAX2175_BAND_VHF;
+
+	/* Add other bands on need basis */
+	return -ENOTSUPP;
+}
+
+static int max2175_update_i2s_mode(struct max2175_ctx *ctx, u32 i2s_mode)
+{
+	/* Only change if it's new */
+	if (max2175_read_bits(ctx, 29, 2, 0) == i2s_mode)
+		return 0;
+
+	max2175_write_bits(ctx, 29, 2, 0, i2s_mode);
+
+	/* Based on I2S mode value I2S_WORD_CNT values change */
+	if (i2s_mode == MAX2175_I2S_MODE3) {
+		max2175_write_bits(ctx, 30, 6, 0, 1);
+	} else if (i2s_mode == MAX2175_I2S_MODE2 ||
+		   i2s_mode == MAX2175_I2S_MODE4) {
+		max2175_write_bits(ctx, 30, 6, 0, 0);
+	} else if (i2s_mode == MAX2175_I2S_MODE0) {
+		max2175_write_bits(ctx, 30, 6, 0,
+				   ctx->rx_modes[ctx->mode].i2s_word_size);
+	} else {
+		v4l2_err(ctx->client,
+			 "failed: i2s_mode %u unsupported\n", i2s_mode);
+		return 1;
+	}
+	mxm_dbg(ctx, "updated i2s_mode %u\n", i2s_mode);
+	return 0;
+}
+
+static void max2175_i2s_enable(struct max2175_ctx *ctx, bool enable)
+{
+	if (enable) {
+		/* Use old setting */
+		max2175_write_bits(ctx, 104, 3, 0, ctx->i2s_test);
+	} else {
+		/* Cache old setting */
+		ctx->i2s_test = max2175_read_bits(ctx, 104, 3, 0);
+		max2175_write_bits(ctx, 104, 3, 0, 1);
+	}
+	mxm_dbg(ctx, "i2s %s: old val %u\n", enable ? "enabled" : "disabled",
+		ctx->i2s_test);
+}
+
+static void max2175_set_filter_coeffs(struct max2175_ctx *ctx, u8 m_sel,
+				      u8 bank, const u16 *coeffs)
+{
+	u8 i, coeff_addr, upper_address;
+
+	mxm_dbg(ctx, "start: m_sel %d bank %d\n", m_sel, bank);
+	max2175_write_bits(ctx, 114, 5, 4, m_sel);
+
+	if (m_sel == 2)
+		upper_address = 12;
+	else
+		upper_address = 24;
+
+	max2175_set_bit(ctx, 117, 7, 1);
+	for (i = 0; i < upper_address; i++) {
+		coeff_addr = i + (bank * 24);
+		max2175_set_bits(ctx, 115, 7, 0,
+				 (u8)((coeffs[i] >> 8) & 0xff));
+		max2175_set_bits(ctx, 116, 7, 0, (u8)(coeffs[i] & 0xff));
+		max2175_set_bits(ctx, 117, 6, 0, coeff_addr);
+		max2175_flush_regstore(ctx, 115, 3);
+	}
+	max2175_write_bit(ctx, 117, 7, 0);
+}
+
+static void max2175_load_dab_1p2(struct max2175_ctx *ctx)
+{
+	u32 i;
+
+	/* Master is already set on init */
+	for (i = 0; i < ARRAY_SIZE(dab12_map); i++)
+		max2175_reg_write(ctx, dab12_map[i].idx, dab12_map[i].val);
+
+	/* The default settings assume master */
+	if (!ctx->master)
+		max2175_write_bit(ctx, 30, 7, 1);
+
+	/* Cache i2s_test value at this point */
+	ctx->i2s_test = max2175_get_bits(ctx, 104, 3, 0);
+	ctx->decim_ratio = 1;
+
+	/* Load the Channel Filter Coefficients into channel filter bank #2 */
+	max2175_set_filter_coeffs(ctx, MAX2175_CH_MSEL, 2, ch_coeff_dab1);
+}
+
+static void max2175_set_bbfilter(struct max2175_ctx *ctx)
+{
+	if (MAX2175_IS_BAND_AM(ctx)) {
+		max2175_write_bits(ctx, 12, 3, 0, ctx->rom_bbf_bw_am);
+		mxm_dbg(ctx, "max2175_set_bbfilter: AM: rom value = %d\n",
+			ctx->rom_bbf_bw_am);
+	} else {
+		/* FM or DAB mode */
+		if (MAX2175_IS_DAB_MODE(ctx)) {
+			/* DAB mode. Load ROM values */
+			max2175_write_bits(ctx, 12, 3, 0, ctx->rom_bbf_bw_dab);
+			mxm_dbg(ctx, "max2175_set_bbfilter: DAB: rom value = %d\n",
+				ctx->rom_bbf_bw_dab);
+		} else {
+			/* FM or FM HD mode. Load ROM values */
+			max2175_write_bits(ctx, 12, 3, 0, ctx->rom_bbf_bw_fm);
+			mxm_dbg(ctx, "max2175_set_bbfilter: FM: rom value = %d\n",
+				ctx->rom_bbf_bw_fm);
+		}
+	}
+}
+
+static bool max2175_set_csm_mode(struct max2175_ctx *ctx,
+			  enum max2175_csm_mode new_mode)
+{
+	int ret = max2175_poll_csm_ready(ctx);
+
+	if (ret) {
+		v4l2_err(ctx->client, "csm not ready: new mode %d\n", new_mode);
+		return ret;
+	}
+
+	mxm_dbg(ctx, "set csm mode: new mode %d\n", new_mode);
+
+	max2175_write_bits(ctx, 0, 2, 0, new_mode);
+
+	/* Wait for a fixed settle down time depending on new mode and band */
+	switch (new_mode) {
+	case MAX2175_CSM_MODE_JUMP_FAST_TUNE:
+		if (MAX2175_IS_BAND_AM(ctx)) {
+			usleep_range(1250, 1500);	/* 1.25ms */
+		} else {
+			if (MAX2175_IS_DAB_MODE(ctx))
+				usleep_range(3000, 3500);	/* 3ms */
+			else
+				usleep_range(1250, 1500);	/* 1.25ms */
+		}
+		break;
+
+	/* Other mode switches can be added in the future if needed */
+	default:
+		break;
+	}
+
+	ret = max2175_poll_csm_ready(ctx);
+	if (ret) {
+		v4l2_err(ctx->client, "csm did not settle: new mode %d\n",
+			 new_mode);
+		return ret;
+	}
+	return ret;
+}
+
+static int max2175_csm_action(struct max2175_ctx *ctx,
+			      enum max2175_csm_mode action)
+{
+	int ret;
+	int load_buffer = MAX2175_CSM_MODE_LOAD_TO_BUFFER;
+
+	mxm_dbg(ctx, "csm action: %d\n", action);
+
+	/* Perform one or two CSM mode commands. */
+	switch (action)	{
+	case MAX2175_CSM_MODE_NO_ACTION:
+		/* Take no FSM Action. */
+		return 0;
+	case MAX2175_CSM_MODE_LOAD_TO_BUFFER:
+	case MAX2175_CSM_MODE_PRESET_TUNE:
+	case MAX2175_CSM_MODE_SEARCH:
+	case MAX2175_CSM_MODE_AF_UPDATE:
+	case MAX2175_CSM_MODE_JUMP_FAST_TUNE:
+	case MAX2175_CSM_MODE_CHECK:
+	case MAX2175_CSM_MODE_LOAD_AND_SWAP:
+	case MAX2175_CSM_MODE_END:
+		ret = max2175_set_csm_mode(ctx, action);
+		break;
+	case MAX2175_CSM_MODE_BUFFER_PLUS_PRESET_TUNE:
+		ret = max2175_set_csm_mode(ctx, load_buffer);
+		if (ret) {
+			v4l2_err(ctx->client, "csm action %d load buf failed\n",
+				 action);
+			break;
+		}
+		ret = max2175_set_csm_mode(ctx, MAX2175_CSM_MODE_PRESET_TUNE);
+		break;
+	case MAX2175_CSM_MODE_BUFFER_PLUS_SEARCH:
+		ret = max2175_set_csm_mode(ctx, load_buffer);
+		if (ret) {
+			v4l2_err(ctx->client, "csm action %d load buf failed\n",
+				 action);
+			break;
+		}
+		ret = max2175_set_csm_mode(ctx, MAX2175_CSM_MODE_SEARCH);
+		break;
+	case MAX2175_CSM_MODE_BUFFER_PLUS_AF_UPDATE:
+		ret = max2175_set_csm_mode(ctx, load_buffer);
+		if (ret) {
+			v4l2_err(ctx->client, "csm action %d load buf failed\n",
+				 action);
+			break;
+		}
+		ret = max2175_set_csm_mode(ctx, MAX2175_CSM_MODE_AF_UPDATE);
+		break;
+	case MAX2175_CSM_MODE_BUFFER_PLUS_JUMP_FAST_TUNE:
+		ret = max2175_set_csm_mode(ctx, load_buffer);
+		if (ret) {
+			v4l2_err(ctx->client, "csm action %d load buf failed\n",
+				 action);
+			break;
+		}
+		ret = max2175_set_csm_mode(ctx,
+					   MAX2175_CSM_MODE_JUMP_FAST_TUNE);
+		break;
+	case MAX2175_CSM_MODE_BUFFER_PLUS_CHECK:
+		ret = max2175_set_csm_mode(ctx, load_buffer);
+		if (ret) {
+			v4l2_err(ctx->client, "csm action %d load buf failed\n",
+				 action);
+			break;
+		}
+		ret = max2175_set_csm_mode(ctx, MAX2175_CSM_MODE_CHECK);
+		break;
+	case MAX2175_CSM_MODE_BUFFER_PLUS_LOAD_AND_SWAP:
+		ret = max2175_set_csm_mode(ctx, load_buffer);
+		if (ret) {
+			v4l2_err(ctx->client, "csm action %d load buf failed\n",
+				 action);
+			break;
+		}
+		ret = max2175_set_csm_mode(ctx, MAX2175_CSM_MODE_LOAD_AND_SWAP);
+		break;
+	default:
+		ret = max2175_set_csm_mode(ctx, MAX2175_CSM_MODE_NO_ACTION);
+		break;
+	}
+	return ret;
+}
+
+static int max2175_set_lo_freq(struct max2175_ctx *ctx, u64 lo_freq)
+{
+	int ret;
+	u32 lo_mult;
+	u64 scaled_lo_freq;
+	const u64 scale_factor = 1000000ULL;
+	u64 scaled_npf, scaled_integer, scaled_fraction;
+	u32 frac_desired, int_desired;
+	u8 loband_bits, vcodiv_bits;
+
+	scaled_lo_freq = lo_freq;
+	/* Scale to larger number for precision */
+	scaled_lo_freq = scaled_lo_freq * scale_factor * 100;
+
+	mxm_dbg(ctx, "scaled lo_freq %llu lo_freq %llu\n",
+		scaled_lo_freq, lo_freq);
+
+	if (MAX2175_IS_BAND_AM(ctx)) {
+		if (max2175_get_bit(ctx, 5, 7) == 0)
+			loband_bits = 0;
+			vcodiv_bits = 0;
+			lo_mult = 16;
+	} else if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_FM) {
+		if (lo_freq <= 74700000) {
+			loband_bits = 0;
+			vcodiv_bits = 0;
+			lo_mult = 16;
+		} else if ((lo_freq > 74700000) && (lo_freq <= 110000000)) {
+			loband_bits = 1;
+			vcodiv_bits = 0;
+		} else {
+			loband_bits = 1;
+			vcodiv_bits = 3;
+		}
+		lo_mult = 8;
+	} else if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_VHF) {
+		if (lo_freq <= 210000000) {
+			loband_bits = 2;
+			vcodiv_bits = 2;
+		} else {
+			loband_bits = 2;
+			vcodiv_bits = 1;
+		}
+		lo_mult = 4;
+	} else {
+		loband_bits = 3;
+		vcodiv_bits = 2;
+		lo_mult = 2;
+	}
+
+	if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_L)
+		scaled_npf = (scaled_lo_freq / ctx->xtal_freq / lo_mult) / 100;
+	else
+		scaled_npf = (scaled_lo_freq / ctx->xtal_freq * lo_mult) / 100;
+
+	scaled_integer = scaled_npf / scale_factor * scale_factor;
+	int_desired = (u32)(scaled_npf / scale_factor);
+	scaled_fraction = scaled_npf - scaled_integer;
+	frac_desired = (u32)(scaled_fraction * 1048576 / scale_factor);
+
+	/* Check CSM is not busy */
+	ret = max2175_poll_csm_ready(ctx);
+	if (ret) {
+		v4l2_err(ctx->client, "lo_freq: csm busy. freq %llu\n",
+			 lo_freq);
+		return ret;
+	}
+
+	mxm_dbg(ctx, "loband %u vcodiv %u lo_mult %u scaled_npf %llu\n",
+		loband_bits, vcodiv_bits, lo_mult, scaled_npf);
+	mxm_dbg(ctx, "scaled int %llu frac %llu desired int %u frac %u\n",
+		scaled_integer, scaled_fraction, int_desired, frac_desired);
+
+	/* Write the calculated values to the appropriate registers */
+	max2175_set_bits(ctx, 5, 3, 2, loband_bits);
+	max2175_set_bits(ctx, 6, 7, 6, vcodiv_bits);
+	max2175_set_bits(ctx, 1, 7, 0, (u8)(int_desired & 0xff));
+	max2175_set_bits(ctx, 2, 3, 0, (u8)((frac_desired >> 16) & 0x1f));
+	max2175_set_bits(ctx, 3, 7, 0, (u8)((frac_desired >> 8) & 0xff));
+	max2175_set_bits(ctx, 4, 7, 0, (u8)(frac_desired & 0xff));
+	/* Flush the above registers to device */
+	max2175_flush_regstore(ctx, 1, 6);
+	return ret;
+}
+
+static int max2175_set_nco_freq(struct max2175_ctx *ctx, s64 nco_freq_desired)
+{
+	int ret;
+	u64 clock_rate, abs_nco_freq;
+	s64  nco_freq, nco_val_desired;
+	u32 nco_reg;
+	const u64 scale_factor = 1000000ULL;
+
+	mxm_dbg(ctx, "nco_freq: freq = %lld\n", nco_freq_desired);
+	clock_rate = ctx->xtal_freq / ctx->decim_ratio;
+	nco_freq = -nco_freq_desired;
+
+	if (nco_freq < 0)
+		abs_nco_freq = -nco_freq;
+	else
+		abs_nco_freq = nco_freq;
+
+	/* Scale up the values for precision */
+	if (abs_nco_freq < (clock_rate / 2)) {
+		nco_val_desired = (2 * nco_freq * scale_factor) / clock_rate;
+	} else {
+		if (nco_freq < 0)
+			nco_val_desired = (-2 * (clock_rate - abs_nco_freq) *
+				scale_factor) / clock_rate;
+		else
+			nco_val_desired = (2 * (clock_rate - abs_nco_freq) *
+				scale_factor) / clock_rate;
+	}
+
+	/* Scale down to get the fraction */
+	if (nco_freq < 0)
+		nco_reg = 0x200000 + ((nco_val_desired * 1048576) /
+				      scale_factor);
+	else
+		nco_reg = (nco_val_desired * 1048576) / scale_factor;
+
+	/* Check CSM is not busy */
+	ret = max2175_poll_csm_ready(ctx);
+	if (ret) {
+		v4l2_err(ctx->client, "nco_freq: csm busy. freq %llu\n",
+			 nco_freq);
+		return ret;
+	}
+
+	mxm_dbg(ctx, "clk %llu decim %u abs %llu desired %lld reg %u\n",
+		clock_rate, ctx->decim_ratio, abs_nco_freq,
+		nco_val_desired, nco_reg);
+
+	/* Write the calculated values to the appropriate registers */
+	max2175_set_bits(ctx, 7, 4, 0, (u8)((nco_reg >> 16) & 0x1f));
+	max2175_set_bits(ctx, 8, 7, 0, (u8)((nco_reg >> 8) & 0xff));
+	max2175_set_bits(ctx, 9, 7, 0, (u8)(nco_reg & 0xff));
+	max2175_flush_regstore(ctx, 7, 3);  /* Send all 3 NCO registers. */
+	return ret;
+}
+
+static int max2175_set_rf_freq_non_am_bands(struct max2175_ctx *ctx, u64 freq,
+					    u32 lo_pos)
+{
+	int ret;
+	s64 adj_freq;
+	u64 low_if_freq;
+
+	mxm_dbg(ctx, "rf_freq: non AM bands\n");
+
+	if (MAX2175_IS_FM_MODE(ctx))
+		low_if_freq = 128000;
+	else if (MAX2175_IS_FMHD_MODE(ctx))
+		low_if_freq = 228000;
+	else
+		return max2175_set_lo_freq(ctx, freq);
+
+	if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_VHF) {
+		if (lo_pos == MAX2175_LO_ABOVE_DESIRED)
+			adj_freq = freq + low_if_freq;
+		else
+			adj_freq = freq - low_if_freq;
+	} else {
+		if (lo_pos == MAX2175_LO_ABOVE_DESIRED)
+			adj_freq = freq - low_if_freq;
+		else
+			adj_freq = freq + low_if_freq;
+	}
+
+	ret = max2175_set_lo_freq(ctx, adj_freq);
+	if (ret)
+		return ret;
+
+	return max2175_set_nco_freq(ctx, low_if_freq);
+}
+
+static int max2175_set_rf_freq(struct max2175_ctx *ctx, u64 freq, u32 lo_pos)
+{
+	int ret;
+
+	if (MAX2175_IS_BAND_AM(ctx))
+		ret = max2175_set_nco_freq(ctx, freq);
+	else
+		ret = max2175_set_rf_freq_non_am_bands(ctx, freq, lo_pos);
+
+	if (!ret)
+		mxm_dbg(ctx, "set rf_freq: freq = %llu. done\n", freq);
+
+	return ret;
+}
+
+static int max2175_tune_rf_freq(struct max2175_ctx *ctx, u64 freq, u32 hsls)
+{
+	int ret;
+
+	ret = max2175_set_rf_freq(ctx, freq, hsls);
+	if (ret)
+		return ret;
+
+	ret = max2175_csm_action(ctx,
+				 MAX2175_CSM_MODE_BUFFER_PLUS_JUMP_FAST_TUNE);
+	if (ret)
+		return ret;
+
+	mxm_dbg(ctx, "tuned rf_freq: old %u new %llu\n", ctx->freq, freq);
+	ctx->freq = freq;
+	return ret;
+}
+
+static void max2175_set_hsls(struct max2175_ctx *ctx, u32 lo_pos)
+{
+	mxm_dbg(ctx, "set_hsls: lo_pos = %u\n", lo_pos);
+
+	if (lo_pos == MAX2175_LO_BELOW_DESIRED)	{
+		if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_VHF)
+			max2175_write_bit(ctx, 5, 4, 1);
+		else
+			max2175_write_bit(ctx, 5, 4, 0);
+	} else {
+		if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_VHF)
+			max2175_write_bit(ctx, 5, 4, 0);
+		else
+			max2175_write_bit(ctx, 5, 4, 1);
+	}
+}
+
+static int max2175_set_rx_mode(struct max2175_ctx *ctx, u32 rx_mode,
+			       u32 am_hiz, u32 hsls)
+{
+	mxm_dbg(ctx, "receive mode: %u am_hiz %u\n", rx_mode, am_hiz);
+
+	switch (rx_mode) {
+	case MAX2175_DAB_1_2:
+		max2175_load_dab_1p2(ctx);
+		break;
+
+	/* Other modes can be added in future if needed */
+	default:
+		v4l2_err(ctx->client, "invalid rx_mode %u\n", rx_mode);
+		return -EINVAL;
+	}
+
+	if (am_hiz) {
+		mxm_dbg(ctx, "setting AM HiZ related config\n");
+		max2175_write_bit(ctx, 50, 5, 1);
+		max2175_write_bit(ctx, 90, 7, 1);
+		max2175_write_bits(ctx, 73, 1, 0, 2);
+		max2175_write_bits(ctx, 80, 5, 0, 33);
+	}
+
+	/* Store some of the initial values loaded, which will be needed at
+	 * a later stage
+	 */
+	ctx->nbd_threshold = max2175_get_bits(ctx, 14, 7, 4);
+	ctx->nbd_gain = max2175_get_bits(ctx, 16, 7, 5);
+	ctx->wbd_threshold = max2175_get_bits(ctx, 14, 3, 0);
+	ctx->wbd_gain = max2175_get_bits(ctx, 15, 5, 4);
+	ctx->bbd_threshold = max2175_get_bits(ctx, 15, 3, 0);
+	ctx->bbdclip_threshold = max2175_get_bits(ctx, 35, 7, 5);
+	ctx->lt_wbd_threshold = max2175_get_bits(ctx, 32, 3, 0);
+	ctx->lt_wbd_gain = max2175_get_bits(ctx, 32, 5, 4);
+
+	/* Load BB filter trim values saved in ROM */
+	max2175_set_bbfilter(ctx);
+
+	/* Set HSLS */
+	max2175_set_hsls(ctx, hsls);
+
+	ctx->mode = rx_mode;
+	ctx->mode_resolved = true;
+	return 0;
+}
+
+static bool max2175_is_i2s_rx_mode_valid(struct max2175_ctx *ctx,
+					 u32 mode, u32 i2s_mode)
+{
+	u32 i;
+
+	for (i = 0; i < ARRAY_SIZE(ctx->rx_modes[mode].i2s_modes); i++)
+		if (ctx->rx_modes[mode].i2s_modes[i] == i2s_mode)
+			return true;
+
+	v4l2_err(ctx->client, "i2s_mode %u not suitable for rx mode %u\n",
+		 i2s_mode, mode);
+	return false;
+}
+
+static int max2175_mode_from_freq(struct max2175_ctx *ctx, u32 freq, u32 *mode)
+{
+	u32 i;
+	int band;
+
+	band = max2175_band_from_freq(freq);
+	if (band < 0) {
+		v4l2_err(ctx->client, "mode from freq failed: %u ret %d\n",
+			 freq, band);
+		return 1;
+	}
+
+	/* Pick the first match always */
+	for (i = 0; i <= ctx->rx_mode->maximum; i++) {
+		if (ctx->rx_modes[i].band == band) {
+			*mode = i;
+			mxm_dbg(ctx, "mode from freq: freq %u mode %d\n",
+				freq, *mode);
+			return 0;
+		}
+	}
+	v4l2_err(ctx->client, "mode from freq failed: freq %u\n", freq);
+	return 1;
+}
+
+static bool max2175_is_freq_rx_mode_valid(struct max2175_ctx *ctx,
+					 u32 mode, u32 freq)
+{
+	int band;
+
+	band = max2175_band_from_freq(freq);
+	if (band < 0) {
+		v4l2_err(ctx->client, "freq rx mode failed: freq %u ret %d\n",
+			 freq, band);
+		return band;
+	}
+
+	mxm_dbg(ctx, "freq rx mode valid: freq %u mode %u\n", freq, mode);
+	return (ctx->rx_modes[mode].band == band);
+}
+
+static void max2175_load_adc_presets(struct max2175_ctx *ctx)
+{
+	u32 i;
+
+	for (i = 0; i < 2; i++) {
+		memcpy(&ctx->regs[146 + (i * 55)], &adc_presets[i][0], 23);
+		max2175_flush_regstore(ctx, 146 + (i * 55), 23);
+	}
+}
+
+static int max2175_init_power_manager(struct max2175_ctx *ctx)
+{
+	int ret;
+
+	/* Execute on-chip power-up/calibration */
+	max2175_write_bit(ctx, 99, 2, 0);
+	usleep_range(1000, 1500);
+	max2175_write_bit(ctx, 99, 2, 1);
+
+	/* Wait for the power manager to finish. */
+	ret = max2175_poll_timeout(ctx, 69, 7, 7, 1, 50);
+	if (ret)
+		v4l2_err(ctx->client, "init pm failed\n");
+	return ret;
+}
+
+static int max2175_recalibrate_adc(struct max2175_ctx *ctx)
+{
+	int ret;
+
+	/* ADC Re-calibration */
+	max2175_reg_write(ctx, 150, 0xff);
+	max2175_reg_write(ctx, 205, 0xff);
+	max2175_reg_write(ctx, 147, 0x20);
+	max2175_reg_write(ctx, 147, 0x00);
+	max2175_reg_write(ctx, 202, 0x20);
+	max2175_reg_write(ctx, 202, 0x00);
+
+	ret = max2175_poll_timeout(ctx, 69, 4, 3, 3, 50);
+	if (ret)
+		v4l2_err(ctx->client, "adc recalibration failed\n");
+	return ret;
+}
+
+static u8 max2175_read_rom(struct max2175_ctx *ctx, u8 row)
+{
+	u8 data;
+
+	max2175_write_bit(ctx, 56, 4, 0);
+	max2175_write_bits(ctx, 56, 3, 0, row);
+	usleep_range(2000, 2500);
+
+	data = max2175_reg_read(ctx, 58);
+	max2175_write_bits(ctx, 56, 3, 0, 0);
+
+	mxm_dbg(ctx, "read rom: row 0x%02x, data 0x%02x\n", row, data);
+	return data;
+}
+
+static void max2175_load_from_rom(struct max2175_ctx *ctx)
+{
+	u8 data = 0;
+
+	data = max2175_read_rom(ctx, 0);
+	ctx->rom_bbf_bw_am = (data & 0x0f);
+	max2175_write_bits(ctx, 81, 3, 0, (data >> 4) & 0xf);
+
+	data = max2175_read_rom(ctx, 1);
+	ctx->rom_bbf_bw_fm = (data & 0x0f);
+	ctx->rom_bbf_bw_dab = (data & 0xf0) >> 4;
+
+	data = max2175_read_rom(ctx, 2);
+	max2175_write_bits(ctx, 82, 4, 0, data & 0x1f);
+	max2175_write_bits(ctx, 82, 7, 5, data >> 5);
+
+	data = max2175_read_rom(ctx, 3);
+	if (ctx->am_hiz->val) {
+		data &= 0x0f;
+		data |= (max2175_read_rom(ctx, 7) & 0x40) >> 2;
+		if (!data)
+			data |= 2;
+	} else {
+		data = (data & 0xf0) >> 4;
+		data |= (max2175_read_rom(ctx, 7) & 0x80) >> 3;
+		if (!data)
+			data |= 30;
+	}
+	max2175_write_bits(ctx, 80, 5, 0, data + 31);
+
+	data = max2175_read_rom(ctx, 6);
+	max2175_write_bits(ctx, 81, 7, 6, data >> 6);
+}
+
+static void max2175_load_fm_eu_1p0_full(struct max2175_ctx *ctx)
+{
+	memcpy(&ctx->regs[1], full_fm_eu_1p0, sizeof(full_fm_eu_1p0));
+	ctx->decim_ratio = 36;
+}
+
+static void max2175_load_fm_na_1p0_full(struct max2175_ctx *ctx)
+{
+	memcpy(&ctx->regs[1], full_fm_na_1p0, sizeof(full_fm_na_1p0));
+	ctx->decim_ratio = 27;
+}
+
+static int max2175_core_init(struct max2175_ctx *ctx, u32 refout_bits)
+{
+	int ret;
+
+	/* MAX2175 uses 36.864MHz clock for EU & 40.154MHz for NA region */
+	if (ctx->xtal_freq == MAX2175_EU_XTAL_FREQ)
+		max2175_load_fm_eu_1p0_full(ctx);
+	else
+		max2175_load_fm_na_1p0_full(ctx);
+
+	/* The default settings assume master */
+	if (!ctx->master)
+		max2175_set_bit(ctx, 30, 7, 1);
+
+	mxm_dbg(ctx, "refout_bits %u\n", refout_bits);
+	/* Set REFOUT */
+	max2175_set_bits(ctx, 56, 7, 5, refout_bits);
+
+	/* Send out all the registers to device except register 0 */
+	max2175_flush_regstore(ctx, 1, 145);
+	usleep_range(5000, 5500);
+
+	/* ADC Reset */
+	max2175_write_bit(ctx, 99, 1, 0);
+	usleep_range(1000, 1500);
+	max2175_write_bit(ctx, 99, 1, 1);
+
+	/* Load ADC preset values */
+	max2175_load_adc_presets(ctx);
+
+	/* Initialize the power management state machine */
+	ret = max2175_init_power_manager(ctx);
+	if (ret)
+		return ret;
+	mxm_dbg(ctx, "init pm done\n");
+
+	/* Recalibrate ADC */
+	ret = max2175_recalibrate_adc(ctx);
+	if (ret)
+		return ret;
+	mxm_dbg(ctx, "adc recalibration done\n");
+
+	/* Load ROM values to appropriate registers */
+	max2175_load_from_rom(ctx);
+
+	if (ctx->xtal_freq == MAX2175_EU_XTAL_FREQ) {
+		/* Load FIR coefficients into bank 0 */
+		max2175_set_filter_coeffs(ctx, MAX2175_CH_MSEL, 0,
+					  ch_coeff_fmeu);
+		max2175_set_filter_coeffs(ctx, MAX2175_EQ_MSEL, 0,
+					  eq_coeff_fmeu1_ra02_m6db);
+	} else {
+		/* Load FIR coefficients into bank 0 */
+		max2175_set_filter_coeffs(ctx, MAX2175_CH_MSEL, 0,
+					  ch_coeff_fmna);
+		max2175_set_filter_coeffs(ctx, MAX2175_EQ_MSEL, 0,
+					  eq_coeff_fmna1_ra02_m6db);
+	}
+	mxm_dbg(ctx, "core initialized\n");
+	return 0;
+}
+
+#define max2175_ctx_from_sd(x)	\
+	container_of(x, struct max2175_ctx, sd)
+#define max2175_ctx_from_ctrl(x)	\
+	container_of(x, struct max2175_ctx, ctrl_hdl)
+
+static void max2175_s_ctrl_i2s_mode(struct max2175_ctx *ctx, u32 i2s_mode)
+{
+	mxm_dbg(ctx, "s_ctrl_i2s_mode: %u resolved %d\n", i2s_mode,
+		ctx->mode_resolved);
+
+	/* Update i2s mode on device only when mode is resolved & it is valid
+	 * for the configured mode
+	 */
+	if (ctx->mode_resolved &&
+	    max2175_is_i2s_rx_mode_valid(ctx, ctx->mode, i2s_mode))
+		max2175_update_i2s_mode(ctx, i2s_mode);
+}
+
+static void max2175_s_ctrl_rx_mode(struct max2175_ctx *ctx, u32 rx_mode)
+{
+	int ret;
+
+	/* Load mode. Range check already done */
+	ret = max2175_set_rx_mode(ctx, rx_mode,
+				  ctx->am_hiz->val, ctx->hsls->val);
+	if (ret)
+		return;
+
+	/* Get current i2s_mode and update if needed for given rx_mode */
+	if (max2175_is_i2s_rx_mode_valid(ctx, rx_mode, ctx->i2s_mode->val))
+		max2175_update_i2s_mode(ctx, ctx->i2s_mode->val);
+	else
+		ctx->i2s_mode->val = max2175_read_bits(ctx, 29, 2, 0);
+
+	mxm_dbg(ctx, "s_ctrl_rx_mode: %u curr freq %u\n", rx_mode, ctx->freq);
+	/* Check if current freq valid for mode & update */
+	if (max2175_is_freq_rx_mode_valid(ctx, rx_mode, ctx->freq))
+		max2175_tune_rf_freq(ctx, ctx->freq, ctx->hsls->val);
+	else
+		/* Use default freq of mode if current freq is not valid */
+		max2175_tune_rf_freq(ctx, ctx->rx_modes[rx_mode].freq,
+				     ctx->hsls->val);
+}
+
+static int max2175_s_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct max2175_ctx *ctx = max2175_ctx_from_ctrl(ctrl->handler);
+	int ret = 0;
+
+	mxm_dbg(ctx, "s_ctrl: id 0x%x, val %u\n", ctrl->id, ctrl->val);
+	switch (ctrl->id) {
+	case V4L2_CID_MAX2175_I2S_EN:
+		max2175_i2s_enable(ctx, ctrl->val == 1);
+		break;
+	case V4L2_CID_MAX2175_I2S_MODE:
+		max2175_s_ctrl_i2s_mode(ctx, ctrl->val);
+		break;
+	case V4L2_CID_MAX2175_AM_HIZ:
+		v4l2_ctrl_activate(ctx->am_hiz, false);
+		break;
+	case V4L2_CID_MAX2175_HSLS:
+		v4l2_ctrl_activate(ctx->hsls, false);
+		break;
+	case V4L2_CID_MAX2175_RX_MODE:
+		mxm_dbg(ctx, "rx mode %u\n", ctrl->val);
+		max2175_s_ctrl_rx_mode(ctx, ctrl->val);
+		break;
+	default:
+		v4l2_err(ctx->client, "s:invalid ctrl id 0x%x\n", ctrl->id);
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+static int max2175_get_lna_gain(struct max2175_ctx *ctx)
+{
+	int gain = 0;
+	enum max2175_band band = max2175_get_bits(ctx, 5, 1, 0);
+
+	switch (band) {
+	case MAX2175_BAND_AM:
+		gain = max2175_read_bits(ctx, 51, 3, 1);
+		break;
+	case MAX2175_BAND_FM:
+		gain = max2175_read_bits(ctx, 50, 3, 1);
+		break;
+	case MAX2175_BAND_VHF:
+		gain = max2175_read_bits(ctx, 52, 3, 0);
+		break;
+	default:
+		v4l2_err(ctx->client, "invalid band %d to get rf gain\n", band);
+		break;
+	}
+	return gain;
+}
+
+static int max2175_g_volatile_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct max2175_ctx *ctx = max2175_ctx_from_ctrl(ctrl->handler);
+
+	/* Only the dynamically changing values need to be in g_volatile_ctrl */
+	mxm_dbg(ctx, "g_volatile_ctrl: id 0x%x\n", ctrl->id);
+	switch (ctrl->id) {
+	case V4L2_CID_RF_TUNER_LNA_GAIN:
+		ctrl->val = max2175_get_lna_gain(ctx);
+		break;
+	case V4L2_CID_RF_TUNER_IF_GAIN:
+		ctrl->val = max2175_read_bits(ctx, 49, 4, 0);
+		break;
+	case V4L2_CID_RF_TUNER_PLL_LOCK:
+		ctrl->val = (max2175_read_bits(ctx, 60, 7, 6) == 3);
+		break;
+	default:
+		v4l2_err(ctx->client, "g:invalid ctrl id 0x%x\n", ctrl->id);
+		return -EINVAL;
+	}
+	mxm_dbg(ctx, "g_volatile_ctrl: id 0x%x val %d\n", ctrl->id, ctrl->val);
+	return 0;
+};
+
+static int max2175_set_freq_and_mode(struct max2175_ctx *ctx, u32 freq)
+{
+	u32 rx_mode;
+	int ret;
+
+	/* Get band from frequency */
+	ret = max2175_mode_from_freq(ctx, freq, &rx_mode);
+	if (ret) {
+		v4l2_err(ctx->client, "set freq mode failed: freq %u ret %d\n",
+			 freq, ret);
+		return ret;
+	}
+	mxm_dbg(ctx, "set_freq_and_mode: freq %u rx_mode %d\n", freq, rx_mode);
+
+	/* Load mode */
+	ret = max2175_set_rx_mode(ctx, rx_mode, ctx->am_hiz->val,
+				  ctx->hsls->val);
+	if (ret)
+		return ret;
+
+	/* Get current i2s_mode and update if needed for given rx_mode */
+	if (max2175_is_i2s_rx_mode_valid(ctx, rx_mode, ctx->i2s_mode->val))
+		max2175_update_i2s_mode(ctx, ctx->i2s_mode->val);
+	else
+		v4l2_ctrl_s_ctrl(ctx->i2s_mode,
+				 max2175_read_bits(ctx, 29, 2, 0));
+
+	/* Tune to the new freq given */
+	return max2175_tune_rf_freq(ctx, freq, ctx->hsls->val);
+}
+
+static int max2175_s_frequency(struct v4l2_subdev *sd,
+			       const struct v4l2_frequency *vf)
+{
+	struct max2175_ctx *ctx = max2175_ctx_from_sd(sd);
+	u32 freq;
+	int ret = 0;
+
+	mxm_dbg(ctx, "s_freq: tuner %u type %u freq: new %u, curr %u\n",
+		vf->tuner, vf->type, vf->frequency, ctx->freq);
+
+	if (vf->tuner != 0) {
+		v4l2_err(ctx->client, "s_freq: invalid tuner %u\n", vf->tuner);
+		return -EINVAL;
+	}
+	/* RF freq */
+	freq = clamp(vf->frequency, bands_rf.rangelow, bands_rf.rangehigh);
+	if (ctx->mode_resolved)
+		/* Check new freq valid for mode */
+		if (max2175_is_freq_rx_mode_valid(ctx, ctx->mode, freq))
+			ret = max2175_tune_rf_freq(ctx, freq, ctx->hsls->val);
+		else
+			/* Find default mode for freq and tune to it */
+			ret = max2175_set_freq_and_mode(ctx, freq);
+	else
+		ret = max2175_set_freq_and_mode(ctx, freq);
+
+	mxm_dbg(ctx, "s_freq: ret %d mode %d freq: curr %u\n",
+		ret, ctx->mode, ctx->freq);
+	return ret;
+}
+
+static int max2175_g_frequency(struct v4l2_subdev *sd,
+			       struct v4l2_frequency *vf)
+{
+	struct max2175_ctx *ctx = max2175_ctx_from_sd(sd);
+	int ret = 0;
+
+	if (vf->tuner != 0) {
+		v4l2_err(ctx->client, "g_freq: invalid tuner %u\n", vf->tuner);
+		return -EINVAL;
+	}
+
+	/* RF freq */
+	vf->type = V4L2_TUNER_RF;
+	vf->frequency = ctx->freq;
+	mxm_dbg(ctx, "g_freq: ret %d tuner %u, type %u, vf %u\n",
+		ret, vf->tuner, vf->type, vf->frequency);
+
+	return ret;
+}
+
+static int max2175_enum_freq_bands(struct v4l2_subdev *sd,
+			    struct v4l2_frequency_band *band)
+{
+	struct max2175_ctx *ctx = max2175_ctx_from_sd(sd);
+	int ret = 0;
+
+	if (band->tuner == 0 && band->index == 0)
+		*band = bands_rf;
+	else
+		ret = -EINVAL;
+
+	mxm_dbg(ctx,
+		"enum_freq: ret %d tuner %u type %u index %u low %u high %u\n",
+		ret, band->tuner, band->type, band->index, band->rangelow,
+		band->rangehigh);
+	return ret;
+}
+
+static int max2175_g_tuner(struct v4l2_subdev *sd, struct v4l2_tuner *vt)
+{
+	if (vt->index > 0)
+		return -EINVAL;
+
+	strlcpy(vt->name, "RF", sizeof(vt->name));
+	vt->type = V4L2_TUNER_RF;
+	vt->capability =
+		V4L2_TUNER_CAP_1HZ | V4L2_TUNER_CAP_FREQ_BANDS;
+	vt->rangelow = bands_rf.rangelow;
+	vt->rangehigh = bands_rf.rangehigh;
+	return 0;
+}
+
+static int max2175_s_tuner(struct v4l2_subdev *sd, const struct v4l2_tuner *vt)
+{
+	/* Check tuner index is valid */
+	if (vt->index > 0)
+		return -EINVAL;
+
+	return 0;
+}
+
+static const struct v4l2_subdev_tuner_ops max2175_tuner_ops = {
+	.s_frequency = max2175_s_frequency,
+	.g_frequency = max2175_g_frequency,
+	.enum_freq_bands = max2175_enum_freq_bands,
+	.g_tuner = max2175_g_tuner,
+	.s_tuner = max2175_s_tuner,
+};
+
+static const struct v4l2_subdev_ops max2175_ops = {
+	.tuner = &max2175_tuner_ops,
+};
+
+static const struct v4l2_ctrl_ops max2175_ctrl_ops = {
+	.s_ctrl = max2175_s_ctrl,
+	.g_volatile_ctrl = max2175_g_volatile_ctrl,
+};
+
+static const struct v4l2_ctrl_config max2175_i2s_en = {
+	.ops = &max2175_ctrl_ops,
+	.id = V4L2_CID_MAX2175_I2S_EN,
+	.name = "I2S Enable",
+	.type = V4L2_CTRL_TYPE_BOOLEAN,
+	.min = 0,
+	.max = 1,
+	.step = 1,
+	.def = 1,
+};
+
+static const struct v4l2_ctrl_config max2175_i2s_mode = {
+	.ops = &max2175_ctrl_ops,
+	.id = V4L2_CID_MAX2175_I2S_MODE,
+	.name = "I2S_MODE value",
+	.type = V4L2_CTRL_TYPE_INTEGER,
+	.min = 0,
+	.max = 4,
+	.step = 1,
+	.def = 0,
+};
+
+static const struct v4l2_ctrl_config max2175_am_hiz = {
+	.ops = &max2175_ctrl_ops,
+	.id = V4L2_CID_MAX2175_AM_HIZ,
+	.name = "AM High impedance input",
+	.type = V4L2_CTRL_TYPE_BOOLEAN,
+	.min = 0,
+	.max = 1,
+	.step = 1,
+	.def = 0,
+};
+
+static const struct v4l2_ctrl_config max2175_hsls = {
+	.ops = &max2175_ctrl_ops,
+	.id = V4L2_CID_MAX2175_HSLS,
+	.name = "HSLS above/below desired",
+	.type = V4L2_CTRL_TYPE_INTEGER,
+	.min = 0,
+	.max = 1,
+	.step = 1,
+	.def = 1,
+};
+
+
+/* NOTE: Any addition/deletion in the below list should be reflected in
+ * max2175_modetag enum
+ */
+static const char * const max2175_ctrl_eu_rx_mode_strings[] = {
+	"DAB 1.2",
+	"NULL",
+};
+
+static const char * const max2175_ctrl_na_rx_mode_strings[] = {
+	"NA FM 1.0",
+	"NULL",
+};
+
+static const struct v4l2_ctrl_config max2175_eu_rx_mode = {
+	.ops = &max2175_ctrl_ops,
+	.id = V4L2_CID_MAX2175_RX_MODE,
+	.name = "RX MODE",
+	.type = V4L2_CTRL_TYPE_MENU,
+	.max = ARRAY_SIZE(max2175_ctrl_eu_rx_mode_strings) - 2,
+	.def = 0,
+	.qmenu = max2175_ctrl_eu_rx_mode_strings,
+};
+
+static const struct v4l2_ctrl_config max2175_na_rx_mode = {
+	.ops = &max2175_ctrl_ops,
+	.id = V4L2_CID_MAX2175_RX_MODE,
+	.name = "RX MODE",
+	.type = V4L2_CTRL_TYPE_MENU,
+	.max = ARRAY_SIZE(max2175_ctrl_na_rx_mode_strings) - 2,
+	.def = 0,
+	.qmenu = max2175_ctrl_na_rx_mode_strings,
+};
+
+static u32 max2175_refout_load_to_bits(struct i2c_client *client, u32 load)
+{
+	u32 bits = 0;	/* REFOUT disabled */
+
+	if (load >= 0 && load <= 40)
+		bits = load / 10;
+	else if (load >= 60 && load <= 70)
+		bits = load / 10 - 1;
+	else
+		dev_warn(&client->dev, "invalid refout_load %u\n", load);
+
+	return bits;
+}
+
+static int max2175_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct max2175_ctx *ctx;
+	struct device *dev = &client->dev;
+	struct v4l2_subdev *sd;
+	struct v4l2_ctrl_handler *hdl;
+	struct clk *clk;
+	bool master = true;
+	u32 refout_load, refout_bits = 0;	/* REFOUT disabled */
+	int ret;
+
+	/* Check if the adapter supports the needed features */
+	if (!i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_BYTE_DATA)) {
+		dev_err(&client->dev, "i2c check failed\n");
+		return -EIO;
+	}
+
+	if (of_find_property(client->dev.of_node, "maxim,slave", NULL))
+		master = false;
+
+	if (!of_property_read_u32(client->dev.of_node, "maxim,refout-load",
+				 &refout_load))
+		refout_bits = max2175_refout_load_to_bits(client, refout_load);
+
+	clk = devm_clk_get(&client->dev, "xtal");
+	if (IS_ERR(clk)) {
+		ret = PTR_ERR(clk);
+		dev_err(&client->dev, "cannot get xtal clock %d\n", ret);
+		return -ENODEV;
+	}
+
+	ctx = kzalloc(sizeof(struct max2175_ctx),
+			     GFP_KERNEL);
+	if (ctx == NULL)
+		return -ENOMEM;
+
+	sd = &ctx->sd;
+	ctx->master = master;
+	ctx->mode_resolved = false;
+
+	/* Set the defaults */
+	ctx->freq = bands_rf.rangelow;
+
+	ctx->xtal_freq = clk_get_rate(clk);
+	dev_info(&client->dev, "xtal freq %lluHz\n", ctx->xtal_freq);
+
+	v4l2_i2c_subdev_init(sd, client, &max2175_ops);
+	ctx->client = client;
+
+	sd->flags = V4L2_SUBDEV_FL_HAS_DEVNODE;
+	ctx->dev = dev;
+
+	/* Controls */
+	hdl = &ctx->ctrl_hdl;
+	ret = v4l2_ctrl_handler_init(hdl, 8);
+	if (ret) {
+		dev_err(&client->dev, "ctrl handler init failed\n");
+		goto err;
+	}
+
+	ctx->lna_gain = v4l2_ctrl_new_std(hdl, &max2175_ctrl_ops,
+					  V4L2_CID_RF_TUNER_LNA_GAIN,
+					  0, 15, 1, 2);
+	ctx->lna_gain->flags |= (V4L2_CTRL_FLAG_VOLATILE |
+				 V4L2_CTRL_FLAG_READ_ONLY);
+	ctx->if_gain = v4l2_ctrl_new_std(hdl, &max2175_ctrl_ops,
+					 V4L2_CID_RF_TUNER_IF_GAIN,
+					 0, 31, 1, 0);
+	ctx->if_gain->flags |= (V4L2_CTRL_FLAG_VOLATILE |
+				V4L2_CTRL_FLAG_READ_ONLY);
+	ctx->pll_lock = v4l2_ctrl_new_std(hdl, &max2175_ctrl_ops,
+					  V4L2_CID_RF_TUNER_PLL_LOCK,
+					  0, 1, 1, 0);
+	ctx->pll_lock->flags |= (V4L2_CTRL_FLAG_VOLATILE |
+				 V4L2_CTRL_FLAG_READ_ONLY);
+	ctx->i2s_en = v4l2_ctrl_new_custom(hdl, &max2175_i2s_en, NULL);
+	ctx->i2s_mode = v4l2_ctrl_new_custom(hdl, &max2175_i2s_mode, NULL);
+	ctx->am_hiz = v4l2_ctrl_new_custom(hdl, &max2175_am_hiz, NULL);
+	ctx->hsls = v4l2_ctrl_new_custom(hdl, &max2175_hsls, NULL);
+
+	if (ctx->xtal_freq == MAX2175_EU_XTAL_FREQ) {
+		ctx->rx_mode = v4l2_ctrl_new_custom(hdl,
+						    &max2175_eu_rx_mode, NULL);
+		ctx->rx_modes = (struct max2175_rxmode *)eu_rx_modes;
+	} else {
+		ctx->rx_mode = v4l2_ctrl_new_custom(hdl,
+						    &max2175_na_rx_mode, NULL);
+		ctx->rx_modes = (struct max2175_rxmode *)na_rx_modes;
+	}
+	ctx->sd.ctrl_handler = &ctx->ctrl_hdl;
+
+	ret = v4l2_async_register_subdev(sd);
+	if (ret) {
+		dev_err(&client->dev, "register subdev failed\n");
+		goto err_reg;
+	}
+	dev_info(&client->dev, "subdev registered\n");
+
+	/* Initialize device */
+	ret = max2175_core_init(ctx, refout_bits);
+	if (ret)
+		goto err_init;
+
+	mxm_dbg(ctx, "probed\n");
+	return 0;
+
+err_init:
+	v4l2_async_unregister_subdev(sd);
+err_reg:
+	v4l2_ctrl_handler_free(&ctx->ctrl_hdl);
+err:
+	kfree(ctx);
+	return ret;
+}
+
+static int max2175_remove(struct i2c_client *client)
+{
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct max2175_ctx *ctx = max2175_ctx_from_sd(sd);
+
+	v4l2_ctrl_handler_free(&ctx->ctrl_hdl);
+	v4l2_async_unregister_subdev(sd);
+	mxm_dbg(ctx, "removed\n");
+	kfree(ctx);
+	return 0;
+}
+
+static const struct i2c_device_id max2175_id[] = {
+	{ DRIVER_NAME, 0},
+	{},
+};
+
+MODULE_DEVICE_TABLE(i2c, max2175_id);
+
+static const struct of_device_id max2175_of_ids[] = {
+	{ .compatible = "maxim, max2175", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, max2175_of_ids);
+
+static struct i2c_driver max2175_driver = {
+	.driver = {
+		.name	= DRIVER_NAME,
+		.of_match_table = max2175_of_ids,
+	},
+	.probe		= max2175_probe,
+	.remove		= max2175_remove,
+	.id_table	= max2175_id,
+};
+
+module_i2c_driver(max2175_driver);
+
+MODULE_DESCRIPTION("Maxim MAX2175 RF to Bits tuner driver");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Ramesh Shanmugasundaram <ramesh.shanmugasundaram@bp.renesas.com>");
diff --git a/drivers/media/i2c/max2175/max2175.h b/drivers/media/i2c/max2175/max2175.h
new file mode 100644
index 0000000..61a508b
--- /dev/null
+++ b/drivers/media/i2c/max2175/max2175.h
@@ -0,0 +1,124 @@ 
+/*
+ * Maxim Integrated MAX2175 RF to Bits tuner driver
+ *
+ * This driver & most of the hard coded values are based on the reference
+ * application delivered by Maxim for this chip.
+ *
+ * Copyright (C) 2016 Maxim Integrated Products
+ * Copyright (C) 2016 Renesas Electronics Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __MAX2175_H__
+#define __MAX2175_H__
+
+#include <linux/types.h>
+
+enum max2175_region {
+	MAX2175_REGION_EU = 0,	/* Europe */
+	MAX2175_REGION_NA,	/* North America */
+};
+
+#define MAX2175_EU_XTAL_FREQ	(36864000)	/* In Hz */
+#define MAX2175_NA_XTAL_FREQ	(40186125)	/* In Hz */
+
+enum max2175_band {
+	MAX2175_BAND_AM = 0,
+	MAX2175_BAND_FM,
+	MAX2175_BAND_VHF,
+	MAX2175_BAND_L,
+};
+
+/* NOTE: Any addition/deletion in the below enum should be reflected in
+ * V4L2_CID_MAX2175_RX_MODE ctrl strings
+ */
+enum max2175_modetag {
+	/* EU modes */
+	MAX2175_DAB_1_2 = 0,
+
+	/* Other possible modes to add in future
+	 * MAX2175_DAB_1_0,
+	 * MAX2175_DAB_1_3,
+	 * MAX2175_EU_FM_2_2,
+	 * MAX2175_EU_FM_1_0,
+	 * MAX2175_EU_FMHD_4_0,
+	 * MAX2175_EU_AM_1_0,
+	 * MAX2175_EU_AM_2_2,
+	 */
+
+	/* NA modes */
+	MAX2175_NA_FM_1_0 = 0,
+
+	/* Other possible modes to add in future
+	 * MAX2175_NA_FM_1_2,
+	 * MAX2175_NA_FMHD_1_0,
+	 * MAX2175_NA_FMHD_1_2,
+	 * MAX2175_NA_AM_1_0,
+	 * MAX2175_NA_AM_1_2,
+	 */
+};
+
+/* Supported I2S modes */
+enum {
+	MAX2175_I2S_MODE0 = 0,
+	MAX2175_I2S_MODE1,
+	MAX2175_I2S_MODE2,
+	MAX2175_I2S_MODE3,
+	MAX2175_I2S_MODE4,
+};
+
+/* Coefficient table groups */
+enum {
+	MAX2175_CH_MSEL = 0,
+	MAX2175_EQ_MSEL,
+	MAX2175_AA_MSEL,
+};
+
+/* HSLS LO injection polarity */
+enum {
+	MAX2175_LO_BELOW_DESIRED = 0,
+	MAX2175_LO_ABOVE_DESIRED,
+};
+
+/* Channel FSM modes */
+enum max2175_csm_mode {
+	MAX2175_CSM_MODE_LOAD_TO_BUFFER = 0,
+	MAX2175_CSM_MODE_PRESET_TUNE,
+	MAX2175_CSM_MODE_SEARCH,
+	MAX2175_CSM_MODE_AF_UPDATE,
+	MAX2175_CSM_MODE_JUMP_FAST_TUNE,
+	MAX2175_CSM_MODE_CHECK,
+	MAX2175_CSM_MODE_LOAD_AND_SWAP,
+	MAX2175_CSM_MODE_END,
+	MAX2175_CSM_MODE_BUFFER_PLUS_PRESET_TUNE,
+	MAX2175_CSM_MODE_BUFFER_PLUS_SEARCH,
+	MAX2175_CSM_MODE_BUFFER_PLUS_AF_UPDATE,
+	MAX2175_CSM_MODE_BUFFER_PLUS_JUMP_FAST_TUNE,
+	MAX2175_CSM_MODE_BUFFER_PLUS_CHECK,
+	MAX2175_CSM_MODE_BUFFER_PLUS_LOAD_AND_SWAP,
+	MAX2175_CSM_MODE_NO_ACTION
+};
+
+/* Rx mode */
+struct max2175_rxmode {
+	enum max2175_band band;		/* Associated band */
+	u32 freq;			/* Default freq in Hz */
+	u8 i2s_word_size;		/* Bit value */
+	u8 i2s_modes[4];		/* Supported modes */
+};
+
+/* Register map */
+struct max2175_regmap {
+	u8 idx;				/* Register index */
+	u8 val;				/* Register value */
+};
+
+#endif /* __MAX2175_H__ */