LinuxTV Patchwork [v2,8/9] phy: Add Cadence D-PHY support

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Submitter Maxime Ripard
Date Nov. 6, 2018, 2:54 p.m.
Message ID <4ec9e47fb5aa9794f69a8e75a04108055094c056.1541516029.git-series.maxime.ripard@bootlin.com>
Download mbox | patch
Permalink /patch/52815/
State Superseded
Delegated to: Sakari Ailus
Headers show

Comments

Maxime Ripard - Nov. 6, 2018, 2:54 p.m.
Cadence has designed a D-PHY that can be used by the, currently in tree,
DSI bridge (DRM), CSI Transceiver and CSI Receiver (v4l2) drivers.

Only the DSI driver has an ad-hoc driver for that phy at the moment, while
the v4l2 drivers are completely missing any phy support. In order to make
that phy support available to all these drivers, without having to
duplicate that code three times, let's create a generic phy framework
driver.

Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
---
 Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt |  21 +-
 Documentation/devicetree/bindings/phy/cdns,dphy.txt           |  20 +-
 drivers/phy/cadence/Kconfig                                   |  13 +-
 drivers/phy/cadence/Makefile                                  |   1 +-
 drivers/phy/cadence/cdns-dphy.c                               | 459 +++++++-
 5 files changed, 492 insertions(+), 22 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/phy/cdns,dphy.txt
 create mode 100644 drivers/phy/cadence/cdns-dphy.c
Kishon Vijay Abraham I - Nov. 12, 2018, 9:51 a.m.
Hi Maxime,

On 06/11/18 8:24 PM, Maxime Ripard wrote:
> Cadence has designed a D-PHY that can be used by the, currently in tree,
> DSI bridge (DRM), CSI Transceiver and CSI Receiver (v4l2) drivers.
> 
> Only the DSI driver has an ad-hoc driver for that phy at the moment, while
> the v4l2 drivers are completely missing any phy support. In order to make
> that phy support available to all these drivers, without having to
> duplicate that code three times, let's create a generic phy framework
> driver.
> 
> Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
> ---
>  Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt |  21 +-
>  Documentation/devicetree/bindings/phy/cdns,dphy.txt           |  20 +-
>  drivers/phy/cadence/Kconfig                                   |  13 +-
>  drivers/phy/cadence/Makefile                                  |   1 +-
>  drivers/phy/cadence/cdns-dphy.c                               | 459 +++++++-
>  5 files changed, 492 insertions(+), 22 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/phy/cdns,dphy.txt
>  create mode 100644 drivers/phy/cadence/cdns-dphy.c
> 
> diff --git a/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt b/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt
> index f5725bb6c61c..525a4bfd8634 100644
> --- a/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt
> +++ b/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt
> @@ -31,28 +31,7 @@ Required subnodes:
>  - one subnode per DSI device connected on the DSI bus. Each DSI device should
>    contain a reg property encoding its virtual channel.
>  
> -Cadence DPHY
> -============
> -
> -Cadence DPHY block.
> -
> -Required properties:
> -- compatible: should be set to "cdns,dphy".
> -- reg: physical base address and length of the DPHY registers.
> -- clocks: DPHY reference clocks.
> -- clock-names: must contain "psm" and "pll_ref".
> -- #phy-cells: must be set to 0.
> -
> -
>  Example:
> -	dphy0: dphy@fd0e0000{
> -		compatible = "cdns,dphy";
> -		reg = <0x0 0xfd0e0000 0x0 0x1000>;
> -		clocks = <&psm_clk>, <&pll_ref_clk>;
> -		clock-names = "psm", "pll_ref";
> -		#phy-cells = <0>;
> -	};
> -
>  	dsi0: dsi@fd0c0000 {
>  		compatible = "cdns,dsi";
>  		reg = <0x0 0xfd0c0000 0x0 0x1000>;
> diff --git a/Documentation/devicetree/bindings/phy/cdns,dphy.txt b/Documentation/devicetree/bindings/phy/cdns,dphy.txt
> new file mode 100644
> index 000000000000..1095bc4e72d9
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/phy/cdns,dphy.txt
> @@ -0,0 +1,20 @@
> +Cadence DPHY
> +============
> +
> +Cadence DPHY block.
> +
> +Required properties:
> +- compatible: should be set to "cdns,dphy".
> +- reg: physical base address and length of the DPHY registers.
> +- clocks: DPHY reference clocks.
> +- clock-names: must contain "psm" and "pll_ref".
> +- #phy-cells: must be set to 0.
> +
> +Example:
> +	dphy0: dphy@fd0e0000{
> +		compatible = "cdns,dphy";
> +		reg = <0x0 0xfd0e0000 0x0 0x1000>;
> +		clocks = <&psm_clk>, <&pll_ref_clk>;
> +		clock-names = "psm", "pll_ref";
> +		#phy-cells = <0>;
> +	};
> diff --git a/drivers/phy/cadence/Kconfig b/drivers/phy/cadence/Kconfig
> index 57fff7de4031..240effa81046 100644
> --- a/drivers/phy/cadence/Kconfig
> +++ b/drivers/phy/cadence/Kconfig
> @@ -1,6 +1,7 @@
>  #
> -# Phy driver for Cadence MHDP DisplayPort controller
> +# Phy drivers for Cadence IPs
>  #
> +
>  config PHY_CADENCE_DP
>  	tristate "Cadence MHDP DisplayPort PHY driver"
>  	depends on OF
> @@ -8,3 +9,13 @@ config PHY_CADENCE_DP
>  	select GENERIC_PHY
>  	help
>  	  Support for Cadence MHDP DisplayPort PHY.
> +
> +config PHY_CADENCE_DPHY
> +	tristate "Cadence D-PHY Support"
> +	depends on HAS_IOMEM && OF
> +	select GENERIC_PHY
> +	select GENERIC_PHY_MIPI_DPHY
> +	help
> +	  Choose this option if you have a Cadence D-PHY in your
> +	  system. If M is selected, the module will be called
> +	  cdns-csi.
> diff --git a/drivers/phy/cadence/Makefile b/drivers/phy/cadence/Makefile
> index e5b0a11cf28a..64cb9ea66ceb 100644
> --- a/drivers/phy/cadence/Makefile
> +++ b/drivers/phy/cadence/Makefile
> @@ -1 +1,2 @@
>  obj-$(CONFIG_PHY_CADENCE_DP)	+= phy-cadence-dp.o
> +obj-$(CONFIG_PHY_CADENCE_DPHY)	+= cdns-dphy.o
> diff --git a/drivers/phy/cadence/cdns-dphy.c b/drivers/phy/cadence/cdns-dphy.c
> new file mode 100644
> index 000000000000..a398b401e5d3
> --- /dev/null
> +++ b/drivers/phy/cadence/cdns-dphy.c
> @@ -0,0 +1,459 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright: 2017-2018 Cadence Design Systems, Inc.
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/reset.h>
> +
> +#include <linux/phy/phy.h>
> +#include <linux/phy/phy-mipi-dphy.h>
> +
> +#define REG_WAKEUP_TIME_NS		800
> +#define DPHY_PLL_RATE_HZ		108000000
> +
> +/* DPHY registers */
> +#define DPHY_PMA_CMN(reg)		(reg)
> +#define DPHY_PMA_LCLK(reg)		(0x100 + (reg))
> +#define DPHY_PMA_LDATA(lane, reg)	(0x200 + ((lane) * 0x100) + (reg))
> +#define DPHY_PMA_RCLK(reg)		(0x600 + (reg))
> +#define DPHY_PMA_RDATA(lane, reg)	(0x700 + ((lane) * 0x100) + (reg))
> +#define DPHY_PCS(reg)			(0xb00 + (reg))
> +
> +#define DPHY_CMN_SSM			DPHY_PMA_CMN(0x20)
> +#define DPHY_CMN_SSM_EN			BIT(0)
> +#define DPHY_CMN_TX_MODE_EN		BIT(9)
> +
> +#define DPHY_CMN_PWM			DPHY_PMA_CMN(0x40)
> +#define DPHY_CMN_PWM_DIV(x)		((x) << 20)
> +#define DPHY_CMN_PWM_LOW(x)		((x) << 10)
> +#define DPHY_CMN_PWM_HIGH(x)		(x)
> +
> +#define DPHY_CMN_FBDIV			DPHY_PMA_CMN(0x4c)
> +#define DPHY_CMN_FBDIV_VAL(low, high)	(((high) << 11) | ((low) << 22))
> +#define DPHY_CMN_FBDIV_FROM_REG		(BIT(10) | BIT(21))
> +
> +#define DPHY_CMN_OPIPDIV		DPHY_PMA_CMN(0x50)
> +#define DPHY_CMN_IPDIV_FROM_REG		BIT(0)
> +#define DPHY_CMN_IPDIV(x)		((x) << 1)
> +#define DPHY_CMN_OPDIV_FROM_REG		BIT(6)
> +#define DPHY_CMN_OPDIV(x)		((x) << 7)
> +
> +#define DPHY_PSM_CFG			DPHY_PCS(0x4)
> +#define DPHY_PSM_CFG_FROM_REG		BIT(0)
> +#define DPHY_PSM_CLK_DIV(x)		((x) << 1)
> +
> +#define DSI_HBP_FRAME_OVERHEAD		12
> +#define DSI_HSA_FRAME_OVERHEAD		14
> +#define DSI_HFP_FRAME_OVERHEAD		6
> +#define DSI_HSS_VSS_VSE_FRAME_OVERHEAD	4
> +#define DSI_BLANKING_FRAME_OVERHEAD	6
> +#define DSI_NULL_FRAME_OVERHEAD		6
> +#define DSI_EOT_PKT_SIZE		4
> +
> +struct cdns_dphy_cfg {
> +	u8 pll_ipdiv;
> +	u8 pll_opdiv;
> +	u16 pll_fbdiv;
> +	unsigned int nlanes;
> +};
> +
> +enum cdns_dphy_clk_lane_cfg {
> +	DPHY_CLK_CFG_LEFT_DRIVES_ALL = 0,
> +	DPHY_CLK_CFG_LEFT_DRIVES_RIGHT = 1,
> +	DPHY_CLK_CFG_LEFT_DRIVES_LEFT = 2,
> +	DPHY_CLK_CFG_RIGHT_DRIVES_ALL = 3,
> +};
> +
> +struct cdns_dphy;
> +struct cdns_dphy_ops {
> +	int (*probe)(struct cdns_dphy *dphy);
> +	void (*remove)(struct cdns_dphy *dphy);
> +	void (*set_psm_div)(struct cdns_dphy *dphy, u8 div);
> +	void (*set_clk_lane_cfg)(struct cdns_dphy *dphy,
> +				 enum cdns_dphy_clk_lane_cfg cfg);
> +	void (*set_pll_cfg)(struct cdns_dphy *dphy,
> +			    const struct cdns_dphy_cfg *cfg);
> +	unsigned long (*get_wakeup_time_ns)(struct cdns_dphy *dphy);
> +};
> +
> +struct cdns_dphy {
> +	struct cdns_dphy_cfg cfg;
> +	void __iomem *regs;
> +	struct clk *psm_clk;
> +	struct clk *pll_ref_clk;
> +	const struct cdns_dphy_ops *ops;
> +	struct phy *phy;
> +};
> +
> +static int cdns_dsi_get_dphy_pll_cfg(struct cdns_dphy *dphy,
> +				     struct cdns_dphy_cfg *cfg,
> +				     struct phy_configure_opts_mipi_dphy *opts,
> +				     unsigned int *dsi_hfp_ext)
> +{
> +	u64 dlane_bps, dlane_bps_max, fbdiv, fbdiv_max, adj_dsi_htotal;
> +	unsigned long pll_ref_hz = clk_get_rate(dphy->pll_ref_clk);
> +
> +	memset(cfg, 0, sizeof(*cfg));
> +
> +	if (pll_ref_hz < 9600000 || pll_ref_hz >= 150000000)
> +		return -EINVAL;
> +	else if (pll_ref_hz < 19200000)
> +		cfg->pll_ipdiv = 1;
> +	else if (pll_ref_hz < 38400000)
> +		cfg->pll_ipdiv = 2;
> +	else if (pll_ref_hz < 76800000)
> +		cfg->pll_ipdiv = 4;
> +	else
> +		cfg->pll_ipdiv = 8;
> +
> +	dlane_bps = opts->hs_clk_rate;
> +
> +	if (dlane_bps > 2500000000UL || dlane_bps < 160000000UL)
> +		return -EINVAL;
> +	else if (dlane_bps >= 1250000000)
> +		cfg->pll_opdiv = 1;
> +	else if (dlane_bps >= 630000000)
> +		cfg->pll_opdiv = 2;
> +	else if (dlane_bps >= 320000000)
> +		cfg->pll_opdiv = 4;
> +	else if (dlane_bps >= 160000000)
> +		cfg->pll_opdiv = 8;
> +
> +	/*
> +	 * Allow a deviation of 0.2% on the per-lane data rate to try to
> +	 * recover a potential mismatch between DPI and PPI clks.
> +	 */
> +	dlane_bps_max = dlane_bps + DIV_ROUND_DOWN_ULL(dlane_bps, 500);
> +	fbdiv_max = DIV_ROUND_DOWN_ULL(dlane_bps_max * 2 *
> +				       cfg->pll_opdiv * cfg->pll_ipdiv,
> +				       pll_ref_hz);
> +	fbdiv = DIV_ROUND_UP_ULL(dlane_bps * 2 * cfg->pll_opdiv *
> +				 cfg->pll_ipdiv,
> +				 pll_ref_hz);
> +
> +	/*
> +	 * Iterate over all acceptable fbdiv and try to find an adjusted DSI
> +	 * htotal length providing an exact match.
> +	 *
> +	 * Note that we could do something even trickier by relying on the fact
> +	 * that a new line is not necessarily aligned on a lane boundary, so,
> +	 * by making adj_dsi_htotal non aligned on a dsi_lanes we can improve a
> +	 * bit the precision. With this, the step would be
> +	 *
> +	 *	pll_ref_hz / (2 * opdiv * ipdiv * nlanes)
> +	 *
> +	 * instead of
> +	 *
> +	 *	pll_ref_hz / (2 * opdiv * ipdiv)
> +	 *
> +	 * The drawback of this approach is that we would need to make sure the
> +	 * number or lines is a multiple of the realignment periodicity which is
> +	 * a function of the number of lanes and the original misalignment. For
> +	 * example, for NLANES = 4 and HTOTAL % NLANES = 3, it takes 4 lines
> +	 * to realign on a lane:
> +	 * LINE 0: expected number of bytes, starts emitting first byte of
> +	 *	   LINE 1 on LANE 3
> +	 * LINE 1: expected number of bytes, starts emitting first 2 bytes of
> +	 *	   LINE 2 on LANES 2 and 3
> +	 * LINE 2: expected number of bytes, starts emitting first 3 bytes of
> +	 *	   of LINE 3 on LANES 1, 2 and 3
> +	 * LINE 3: one byte less, now things are realigned on LANE 0 for LINE 4
> +	 *
> +	 * I figured this extra complexity was not worth the benefit, but if
> +	 * someone really has unfixable mismatch, that would be something to
> +	 * investigate.
> +	 */
> +	for (; fbdiv <= fbdiv_max; fbdiv++) {
> +		u32 rem;
> +
> +		/*
> +		 * Do the division in 2 steps to avoid an overflow on the
> +		 * divider.
> +		 */
> +		rem = do_div(adj_dsi_htotal, opts->hs_clk_rate);
> +		if (rem)
> +			continue;
> +
> +		rem = do_div(adj_dsi_htotal,
> +			     cfg->pll_opdiv * cfg->pll_ipdiv * 2 * 8);
> +		if (rem)
> +			continue;
> +
> +		cfg->pll_fbdiv = fbdiv;
> +		break;
> +	}
> +
> +	/* No match, let's just reject the display mode. */
> +	if (!cfg->pll_fbdiv)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static int cdns_dphy_setup_psm(struct cdns_dphy *dphy)
> +{
> +	unsigned long psm_clk_hz = clk_get_rate(dphy->psm_clk);
> +	unsigned long psm_div;
> +
> +	if (!psm_clk_hz || psm_clk_hz > 100000000)
> +		return -EINVAL;
> +
> +	psm_div = DIV_ROUND_CLOSEST(psm_clk_hz, 1000000);
> +	if (dphy->ops->set_psm_div)
> +		dphy->ops->set_psm_div(dphy, psm_div);
> +
> +	return 0;
> +}
> +
> +static void cdns_dphy_set_clk_lane_cfg(struct cdns_dphy *dphy,
> +				       enum cdns_dphy_clk_lane_cfg cfg)
> +{
> +	if (dphy->ops->set_clk_lane_cfg)
> +		dphy->ops->set_clk_lane_cfg(dphy, cfg);
> +}
> +
> +static void cdns_dphy_set_pll_cfg(struct cdns_dphy *dphy,
> +				  const struct cdns_dphy_cfg *cfg)
> +{
> +	if (dphy->ops->set_pll_cfg)
> +		dphy->ops->set_pll_cfg(dphy, cfg);
> +}
> +
> +static unsigned long cdns_dphy_get_wakeup_time_ns(struct cdns_dphy *dphy)
> +{
> +	return dphy->ops->get_wakeup_time_ns(dphy);
> +}
> +
> +static unsigned long cdns_dphy_ref_get_wakeup_time_ns(struct cdns_dphy *dphy)
> +{
> +	/* Default wakeup time is 800 ns (in a simulated environment). */
> +	return 800;
> +}
> +
> +static void cdns_dphy_ref_set_pll_cfg(struct cdns_dphy *dphy,
> +				      const struct cdns_dphy_cfg *cfg)
> +{
> +	u32 fbdiv_low, fbdiv_high;
> +
> +	fbdiv_low = (cfg->pll_fbdiv / 4) - 2;
> +	fbdiv_high = cfg->pll_fbdiv - fbdiv_low - 2;
> +
> +	writel(DPHY_CMN_IPDIV_FROM_REG | DPHY_CMN_OPDIV_FROM_REG |
> +	       DPHY_CMN_IPDIV(cfg->pll_ipdiv) |
> +	       DPHY_CMN_OPDIV(cfg->pll_opdiv),
> +	       dphy->regs + DPHY_CMN_OPIPDIV);
> +	writel(DPHY_CMN_FBDIV_FROM_REG |
> +	       DPHY_CMN_FBDIV_VAL(fbdiv_low, fbdiv_high),
> +	       dphy->regs + DPHY_CMN_FBDIV);
> +	writel(DPHY_CMN_PWM_HIGH(6) | DPHY_CMN_PWM_LOW(0x101) |
> +	       DPHY_CMN_PWM_DIV(0x8),
> +	       dphy->regs + DPHY_CMN_PWM);
> +}
> +
> +static void cdns_dphy_ref_set_psm_div(struct cdns_dphy *dphy, u8 div)
> +{
> +	writel(DPHY_PSM_CFG_FROM_REG | DPHY_PSM_CLK_DIV(div),
> +	       dphy->regs + DPHY_PSM_CFG);
> +}
> +
> +/*
> + * This is the reference implementation of DPHY hooks. Specific integration of
> + * this IP may have to re-implement some of them depending on how they decided
> + * to wire things in the SoC.
> + */
> +static const struct cdns_dphy_ops ref_dphy_ops = {
> +	.get_wakeup_time_ns = cdns_dphy_ref_get_wakeup_time_ns,
> +	.set_pll_cfg = cdns_dphy_ref_set_pll_cfg,
> +	.set_psm_div = cdns_dphy_ref_set_psm_div,
> +};
> +
> +static int cdns_dphy_config_from_opts(struct phy *phy,
> +				      struct phy_configure_opts_mipi_dphy *opts,
> +				      struct cdns_dphy_cfg *cfg)
> +{
> +	struct cdns_dphy *dphy = phy_get_drvdata(phy);
> +	unsigned int dsi_hfp_ext = 0;
> +	int ret;
> +
> +	ret = phy_mipi_dphy_config_validate(opts);
> +	if (ret)
> +		return ret;
> +
> +	ret = cdns_dsi_get_dphy_pll_cfg(dphy, cfg,
> +					opts, &dsi_hfp_ext);
> +	if (ret)
> +		return ret;
> +
> +	opts->wakeup = cdns_dphy_get_wakeup_time_ns(dphy);
> +
> +	return 0;
> +}
> +
> +static int cdns_dphy_init(struct phy *phy)
> +{
> +	struct cdns_dphy *dphy = phy_get_drvdata(phy);
> +
> +	clk_prepare_enable(dphy->psm_clk);
> +	clk_prepare_enable(dphy->pll_ref_clk);
> +
> +	return 0;
> +}
> +
> +static int cdns_dphy_validate(struct phy *phy, enum phy_mode mode,
> +			      union phy_configure_opts *opts)
> +{
> +	struct cdns_dphy_cfg cfg = { 0 };
> +
> +	if (mode != PHY_MODE_MIPI_DPHY)
> +		return -EINVAL;
> +
> +	return cdns_dphy_config_from_opts(phy, &opts->mipi_dphy, &cfg);
> +}
> +
> +static int cdns_dphy_configure(struct phy *phy, union phy_configure_opts *opts)
> +{
> +	struct cdns_dphy *dphy = phy_get_drvdata(phy);
> +	struct cdns_dphy_cfg cfg = { 0 };
> +	int ret;
> +
> +	ret = cdns_dphy_config_from_opts(phy, &opts->mipi_dphy, &cfg);
> +	if (ret)
> +		return ret;

Can you explain why you need the same function to be invoked from both validate
and configure callback? I see this to be redundant.

Thanks
Kishon
Maxime Ripard - Nov. 16, 2018, 9:17 a.m.
Hi!

On Mon, Nov 12, 2018 at 03:21:56PM +0530, Kishon Vijay Abraham I wrote:
> > +static int cdns_dphy_validate(struct phy *phy, enum phy_mode mode,
> > +			      union phy_configure_opts *opts)
> > +{
> > +	struct cdns_dphy_cfg cfg = { 0 };
> > +
> > +	if (mode != PHY_MODE_MIPI_DPHY)
> > +		return -EINVAL;
> > +
> > +	return cdns_dphy_config_from_opts(phy, &opts->mipi_dphy, &cfg);
> > +}
> > +
> > +static int cdns_dphy_configure(struct phy *phy, union phy_configure_opts *opts)
> > +{
> > +	struct cdns_dphy *dphy = phy_get_drvdata(phy);
> > +	struct cdns_dphy_cfg cfg = { 0 };
> > +	int ret;
> > +
> > +	ret = cdns_dphy_config_from_opts(phy, &opts->mipi_dphy, &cfg);
> > +	if (ret)
> > +		return ret;
> 
> Can you explain why you need the same function to be invoked from both validate
> and configure callback? I see this to be redundant.

Sure.

Validate and configure serve two rather different purposes. validate
is here to make sure that a configuration can work with the PHY, and
to let the phy adjust the configuration to find a more optimal one.

configure, on the other hand, apply a configuration. We still have to
make sure that the configuration can work, since:
  - We might have called validate any number of times, with any number
    of configurations before calling configure, so we don't know which
    configuration we validate is actually going to be applied later on
    (if it's even applied)
  - If we don't care about the validation at all, we might just call
    configure directly

Does that make sense?

Maxime
Sakari Ailus - Nov. 19, 2018, 9:24 p.m.
Hi Maxime,

On Tue, Nov 06, 2018 at 03:54:20PM +0100, Maxime Ripard wrote:
> Cadence has designed a D-PHY that can be used by the, currently in tree,
> DSI bridge (DRM), CSI Transceiver and CSI Receiver (v4l2) drivers.
> 
> Only the DSI driver has an ad-hoc driver for that phy at the moment, while
> the v4l2 drivers are completely missing any phy support. In order to make
> that phy support available to all these drivers, without having to
> duplicate that code three times, let's create a generic phy framework
> driver.
> 
> Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
> ---
>  Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt |  21 +-
>  Documentation/devicetree/bindings/phy/cdns,dphy.txt           |  20 +-

Coould you split out the DT binding changes into a separate patch?

>  drivers/phy/cadence/Kconfig                                   |  13 +-
>  drivers/phy/cadence/Makefile                                  |   1 +-
>  drivers/phy/cadence/cdns-dphy.c                               | 459 +++++++-
>  5 files changed, 492 insertions(+), 22 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/phy/cdns,dphy.txt
>  create mode 100644 drivers/phy/cadence/cdns-dphy.c
> 
> diff --git a/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt b/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt
> index f5725bb6c61c..525a4bfd8634 100644
> --- a/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt
> +++ b/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt
> @@ -31,28 +31,7 @@ Required subnodes:
>  - one subnode per DSI device connected on the DSI bus. Each DSI device should
>    contain a reg property encoding its virtual channel.
>  
> -Cadence DPHY
> -============
> -
> -Cadence DPHY block.
> -
> -Required properties:
> -- compatible: should be set to "cdns,dphy".
> -- reg: physical base address and length of the DPHY registers.
> -- clocks: DPHY reference clocks.
> -- clock-names: must contain "psm" and "pll_ref".
> -- #phy-cells: must be set to 0.
> -
> -
>  Example:
> -	dphy0: dphy@fd0e0000{
> -		compatible = "cdns,dphy";
> -		reg = <0x0 0xfd0e0000 0x0 0x1000>;
> -		clocks = <&psm_clk>, <&pll_ref_clk>;
> -		clock-names = "psm", "pll_ref";
> -		#phy-cells = <0>;
> -	};
> -
>  	dsi0: dsi@fd0c0000 {
>  		compatible = "cdns,dsi";
>  		reg = <0x0 0xfd0c0000 0x0 0x1000>;
> diff --git a/Documentation/devicetree/bindings/phy/cdns,dphy.txt b/Documentation/devicetree/bindings/phy/cdns,dphy.txt
> new file mode 100644
> index 000000000000..1095bc4e72d9
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/phy/cdns,dphy.txt
> @@ -0,0 +1,20 @@
> +Cadence DPHY
> +============
> +
> +Cadence DPHY block.
> +
> +Required properties:
> +- compatible: should be set to "cdns,dphy".
> +- reg: physical base address and length of the DPHY registers.
> +- clocks: DPHY reference clocks.
> +- clock-names: must contain "psm" and "pll_ref".
> +- #phy-cells: must be set to 0.
> +
> +Example:
> +	dphy0: dphy@fd0e0000{
> +		compatible = "cdns,dphy";
> +		reg = <0x0 0xfd0e0000 0x0 0x1000>;
> +		clocks = <&psm_clk>, <&pll_ref_clk>;
> +		clock-names = "psm", "pll_ref";
> +		#phy-cells = <0>;
> +	};
> diff --git a/drivers/phy/cadence/Kconfig b/drivers/phy/cadence/Kconfig
> index 57fff7de4031..240effa81046 100644
> --- a/drivers/phy/cadence/Kconfig
> +++ b/drivers/phy/cadence/Kconfig
> @@ -1,6 +1,7 @@
>  #
> -# Phy driver for Cadence MHDP DisplayPort controller
> +# Phy drivers for Cadence IPs
>  #
> +
>  config PHY_CADENCE_DP
>  	tristate "Cadence MHDP DisplayPort PHY driver"
>  	depends on OF
> @@ -8,3 +9,13 @@ config PHY_CADENCE_DP
>  	select GENERIC_PHY
>  	help
>  	  Support for Cadence MHDP DisplayPort PHY.
> +
> +config PHY_CADENCE_DPHY
> +	tristate "Cadence D-PHY Support"
> +	depends on HAS_IOMEM && OF
> +	select GENERIC_PHY
> +	select GENERIC_PHY_MIPI_DPHY
> +	help
> +	  Choose this option if you have a Cadence D-PHY in your
> +	  system. If M is selected, the module will be called
> +	  cdns-csi.
> diff --git a/drivers/phy/cadence/Makefile b/drivers/phy/cadence/Makefile
> index e5b0a11cf28a..64cb9ea66ceb 100644
> --- a/drivers/phy/cadence/Makefile
> +++ b/drivers/phy/cadence/Makefile
> @@ -1 +1,2 @@
>  obj-$(CONFIG_PHY_CADENCE_DP)	+= phy-cadence-dp.o
> +obj-$(CONFIG_PHY_CADENCE_DPHY)	+= cdns-dphy.o
> diff --git a/drivers/phy/cadence/cdns-dphy.c b/drivers/phy/cadence/cdns-dphy.c
> new file mode 100644
> index 000000000000..a398b401e5d3
> --- /dev/null
> +++ b/drivers/phy/cadence/cdns-dphy.c
> @@ -0,0 +1,459 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright: 2017-2018 Cadence Design Systems, Inc.
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/reset.h>
> +
> +#include <linux/phy/phy.h>
> +#include <linux/phy/phy-mipi-dphy.h>
> +
> +#define REG_WAKEUP_TIME_NS		800
> +#define DPHY_PLL_RATE_HZ		108000000
> +
> +/* DPHY registers */
> +#define DPHY_PMA_CMN(reg)		(reg)
> +#define DPHY_PMA_LCLK(reg)		(0x100 + (reg))
> +#define DPHY_PMA_LDATA(lane, reg)	(0x200 + ((lane) * 0x100) + (reg))
> +#define DPHY_PMA_RCLK(reg)		(0x600 + (reg))
> +#define DPHY_PMA_RDATA(lane, reg)	(0x700 + ((lane) * 0x100) + (reg))
> +#define DPHY_PCS(reg)			(0xb00 + (reg))
> +
> +#define DPHY_CMN_SSM			DPHY_PMA_CMN(0x20)
> +#define DPHY_CMN_SSM_EN			BIT(0)
> +#define DPHY_CMN_TX_MODE_EN		BIT(9)
> +
> +#define DPHY_CMN_PWM			DPHY_PMA_CMN(0x40)
> +#define DPHY_CMN_PWM_DIV(x)		((x) << 20)
> +#define DPHY_CMN_PWM_LOW(x)		((x) << 10)
> +#define DPHY_CMN_PWM_HIGH(x)		(x)
> +
> +#define DPHY_CMN_FBDIV			DPHY_PMA_CMN(0x4c)
> +#define DPHY_CMN_FBDIV_VAL(low, high)	(((high) << 11) | ((low) << 22))
> +#define DPHY_CMN_FBDIV_FROM_REG		(BIT(10) | BIT(21))
> +
> +#define DPHY_CMN_OPIPDIV		DPHY_PMA_CMN(0x50)
> +#define DPHY_CMN_IPDIV_FROM_REG		BIT(0)
> +#define DPHY_CMN_IPDIV(x)		((x) << 1)
> +#define DPHY_CMN_OPDIV_FROM_REG		BIT(6)
> +#define DPHY_CMN_OPDIV(x)		((x) << 7)
> +
> +#define DPHY_PSM_CFG			DPHY_PCS(0x4)
> +#define DPHY_PSM_CFG_FROM_REG		BIT(0)
> +#define DPHY_PSM_CLK_DIV(x)		((x) << 1)
> +
> +#define DSI_HBP_FRAME_OVERHEAD		12
> +#define DSI_HSA_FRAME_OVERHEAD		14
> +#define DSI_HFP_FRAME_OVERHEAD		6
> +#define DSI_HSS_VSS_VSE_FRAME_OVERHEAD	4
> +#define DSI_BLANKING_FRAME_OVERHEAD	6
> +#define DSI_NULL_FRAME_OVERHEAD		6
> +#define DSI_EOT_PKT_SIZE		4
> +
> +struct cdns_dphy_cfg {
> +	u8 pll_ipdiv;
> +	u8 pll_opdiv;
> +	u16 pll_fbdiv;
> +	unsigned int nlanes;
> +};
> +
> +enum cdns_dphy_clk_lane_cfg {
> +	DPHY_CLK_CFG_LEFT_DRIVES_ALL = 0,
> +	DPHY_CLK_CFG_LEFT_DRIVES_RIGHT = 1,
> +	DPHY_CLK_CFG_LEFT_DRIVES_LEFT = 2,
> +	DPHY_CLK_CFG_RIGHT_DRIVES_ALL = 3,
> +};
> +
> +struct cdns_dphy;
> +struct cdns_dphy_ops {
> +	int (*probe)(struct cdns_dphy *dphy);
> +	void (*remove)(struct cdns_dphy *dphy);
> +	void (*set_psm_div)(struct cdns_dphy *dphy, u8 div);
> +	void (*set_clk_lane_cfg)(struct cdns_dphy *dphy,
> +				 enum cdns_dphy_clk_lane_cfg cfg);
> +	void (*set_pll_cfg)(struct cdns_dphy *dphy,
> +			    const struct cdns_dphy_cfg *cfg);
> +	unsigned long (*get_wakeup_time_ns)(struct cdns_dphy *dphy);
> +};
> +
> +struct cdns_dphy {
> +	struct cdns_dphy_cfg cfg;
> +	void __iomem *regs;
> +	struct clk *psm_clk;
> +	struct clk *pll_ref_clk;
> +	const struct cdns_dphy_ops *ops;
> +	struct phy *phy;
> +};
> +
> +static int cdns_dsi_get_dphy_pll_cfg(struct cdns_dphy *dphy,
> +				     struct cdns_dphy_cfg *cfg,
> +				     struct phy_configure_opts_mipi_dphy *opts,
> +				     unsigned int *dsi_hfp_ext)
> +{
> +	u64 dlane_bps, dlane_bps_max, fbdiv, fbdiv_max, adj_dsi_htotal;
> +	unsigned long pll_ref_hz = clk_get_rate(dphy->pll_ref_clk);
> +
> +	memset(cfg, 0, sizeof(*cfg));
> +
> +	if (pll_ref_hz < 9600000 || pll_ref_hz >= 150000000)
> +		return -EINVAL;
> +	else if (pll_ref_hz < 19200000)
> +		cfg->pll_ipdiv = 1;
> +	else if (pll_ref_hz < 38400000)
> +		cfg->pll_ipdiv = 2;
> +	else if (pll_ref_hz < 76800000)
> +		cfg->pll_ipdiv = 4;
> +	else
> +		cfg->pll_ipdiv = 8;
> +
> +	dlane_bps = opts->hs_clk_rate;
> +
> +	if (dlane_bps > 2500000000UL || dlane_bps < 160000000UL)
> +		return -EINVAL;
> +	else if (dlane_bps >= 1250000000)
> +		cfg->pll_opdiv = 1;
> +	else if (dlane_bps >= 630000000)
> +		cfg->pll_opdiv = 2;
> +	else if (dlane_bps >= 320000000)
> +		cfg->pll_opdiv = 4;
> +	else if (dlane_bps >= 160000000)
> +		cfg->pll_opdiv = 8;
> +
> +	/*
> +	 * Allow a deviation of 0.2% on the per-lane data rate to try to
> +	 * recover a potential mismatch between DPI and PPI clks.
> +	 */
> +	dlane_bps_max = dlane_bps + DIV_ROUND_DOWN_ULL(dlane_bps, 500);
> +	fbdiv_max = DIV_ROUND_DOWN_ULL(dlane_bps_max * 2 *
> +				       cfg->pll_opdiv * cfg->pll_ipdiv,
> +				       pll_ref_hz);
> +	fbdiv = DIV_ROUND_UP_ULL(dlane_bps * 2 * cfg->pll_opdiv *
> +				 cfg->pll_ipdiv,
> +				 pll_ref_hz);
> +
> +	/*
> +	 * Iterate over all acceptable fbdiv and try to find an adjusted DSI
> +	 * htotal length providing an exact match.
> +	 *
> +	 * Note that we could do something even trickier by relying on the fact
> +	 * that a new line is not necessarily aligned on a lane boundary, so,
> +	 * by making adj_dsi_htotal non aligned on a dsi_lanes we can improve a
> +	 * bit the precision. With this, the step would be
> +	 *
> +	 *	pll_ref_hz / (2 * opdiv * ipdiv * nlanes)
> +	 *
> +	 * instead of
> +	 *
> +	 *	pll_ref_hz / (2 * opdiv * ipdiv)
> +	 *
> +	 * The drawback of this approach is that we would need to make sure the
> +	 * number or lines is a multiple of the realignment periodicity which is
> +	 * a function of the number of lanes and the original misalignment. For
> +	 * example, for NLANES = 4 and HTOTAL % NLANES = 3, it takes 4 lines
> +	 * to realign on a lane:
> +	 * LINE 0: expected number of bytes, starts emitting first byte of
> +	 *	   LINE 1 on LANE 3
> +	 * LINE 1: expected number of bytes, starts emitting first 2 bytes of
> +	 *	   LINE 2 on LANES 2 and 3
> +	 * LINE 2: expected number of bytes, starts emitting first 3 bytes of
> +	 *	   of LINE 3 on LANES 1, 2 and 3
> +	 * LINE 3: one byte less, now things are realigned on LANE 0 for LINE 4
> +	 *
> +	 * I figured this extra complexity was not worth the benefit, but if
> +	 * someone really has unfixable mismatch, that would be something to
> +	 * investigate.
> +	 */
> +	for (; fbdiv <= fbdiv_max; fbdiv++) {
> +		u32 rem;
> +
> +		/*
> +		 * Do the division in 2 steps to avoid an overflow on the
> +		 * divider.
> +		 */
> +		rem = do_div(adj_dsi_htotal, opts->hs_clk_rate);

Hmm. I don't see adj_dsi_htotal being set anywhere. I suppose that can't be
intended.

> +		if (rem)
> +			continue;
> +
> +		rem = do_div(adj_dsi_htotal,
> +			     cfg->pll_opdiv * cfg->pll_ipdiv * 2 * 8);
> +		if (rem)
> +			continue;

Is fbdiv supposed to be used in the formula somewhere?

> +
> +		cfg->pll_fbdiv = fbdiv;
> +		break;
> +	}
> +
> +	/* No match, let's just reject the display mode. */
> +	if (!cfg->pll_fbdiv)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static int cdns_dphy_setup_psm(struct cdns_dphy *dphy)
> +{
> +	unsigned long psm_clk_hz = clk_get_rate(dphy->psm_clk);
> +	unsigned long psm_div;
> +
> +	if (!psm_clk_hz || psm_clk_hz > 100000000)
> +		return -EINVAL;
> +
> +	psm_div = DIV_ROUND_CLOSEST(psm_clk_hz, 1000000);
> +	if (dphy->ops->set_psm_div)
> +		dphy->ops->set_psm_div(dphy, psm_div);
> +
> +	return 0;
> +}
> +
> +static void cdns_dphy_set_clk_lane_cfg(struct cdns_dphy *dphy,
> +				       enum cdns_dphy_clk_lane_cfg cfg)
> +{
> +	if (dphy->ops->set_clk_lane_cfg)
> +		dphy->ops->set_clk_lane_cfg(dphy, cfg);
> +}
> +
> +static void cdns_dphy_set_pll_cfg(struct cdns_dphy *dphy,
> +				  const struct cdns_dphy_cfg *cfg)
> +{
> +	if (dphy->ops->set_pll_cfg)
> +		dphy->ops->set_pll_cfg(dphy, cfg);
> +}
> +
> +static unsigned long cdns_dphy_get_wakeup_time_ns(struct cdns_dphy *dphy)
> +{
> +	return dphy->ops->get_wakeup_time_ns(dphy);
> +}
> +
> +static unsigned long cdns_dphy_ref_get_wakeup_time_ns(struct cdns_dphy *dphy)
> +{
> +	/* Default wakeup time is 800 ns (in a simulated environment). */
> +	return 800;
> +}
> +
> +static void cdns_dphy_ref_set_pll_cfg(struct cdns_dphy *dphy,
> +				      const struct cdns_dphy_cfg *cfg)
> +{
> +	u32 fbdiv_low, fbdiv_high;
> +
> +	fbdiv_low = (cfg->pll_fbdiv / 4) - 2;
> +	fbdiv_high = cfg->pll_fbdiv - fbdiv_low - 2;
> +
> +	writel(DPHY_CMN_IPDIV_FROM_REG | DPHY_CMN_OPDIV_FROM_REG |
> +	       DPHY_CMN_IPDIV(cfg->pll_ipdiv) |
> +	       DPHY_CMN_OPDIV(cfg->pll_opdiv),
> +	       dphy->regs + DPHY_CMN_OPIPDIV);
> +	writel(DPHY_CMN_FBDIV_FROM_REG |
> +	       DPHY_CMN_FBDIV_VAL(fbdiv_low, fbdiv_high),
> +	       dphy->regs + DPHY_CMN_FBDIV);
> +	writel(DPHY_CMN_PWM_HIGH(6) | DPHY_CMN_PWM_LOW(0x101) |
> +	       DPHY_CMN_PWM_DIV(0x8),
> +	       dphy->regs + DPHY_CMN_PWM);
> +}
> +
> +static void cdns_dphy_ref_set_psm_div(struct cdns_dphy *dphy, u8 div)
> +{
> +	writel(DPHY_PSM_CFG_FROM_REG | DPHY_PSM_CLK_DIV(div),
> +	       dphy->regs + DPHY_PSM_CFG);
> +}
> +
> +/*
> + * This is the reference implementation of DPHY hooks. Specific integration of
> + * this IP may have to re-implement some of them depending on how they decided
> + * to wire things in the SoC.
> + */
> +static const struct cdns_dphy_ops ref_dphy_ops = {
> +	.get_wakeup_time_ns = cdns_dphy_ref_get_wakeup_time_ns,
> +	.set_pll_cfg = cdns_dphy_ref_set_pll_cfg,
> +	.set_psm_div = cdns_dphy_ref_set_psm_div,
> +};
> +
> +static int cdns_dphy_config_from_opts(struct phy *phy,
> +				      struct phy_configure_opts_mipi_dphy *opts,
> +				      struct cdns_dphy_cfg *cfg)
> +{
> +	struct cdns_dphy *dphy = phy_get_drvdata(phy);
> +	unsigned int dsi_hfp_ext = 0;
> +	int ret;
> +
> +	ret = phy_mipi_dphy_config_validate(opts);
> +	if (ret)
> +		return ret;
> +
> +	ret = cdns_dsi_get_dphy_pll_cfg(dphy, cfg,
> +					opts, &dsi_hfp_ext);
> +	if (ret)
> +		return ret;
> +
> +	opts->wakeup = cdns_dphy_get_wakeup_time_ns(dphy);
> +
> +	return 0;
> +}
> +
> +static int cdns_dphy_init(struct phy *phy)
> +{
> +	struct cdns_dphy *dphy = phy_get_drvdata(phy);
> +
> +	clk_prepare_enable(dphy->psm_clk);
> +	clk_prepare_enable(dphy->pll_ref_clk);
> +
> +	return 0;
> +}
> +
> +static int cdns_dphy_validate(struct phy *phy, enum phy_mode mode,
> +			      union phy_configure_opts *opts)
> +{
> +	struct cdns_dphy_cfg cfg = { 0 };
> +
> +	if (mode != PHY_MODE_MIPI_DPHY)
> +		return -EINVAL;
> +
> +	return cdns_dphy_config_from_opts(phy, &opts->mipi_dphy, &cfg);
> +}
> +
> +static int cdns_dphy_configure(struct phy *phy, union phy_configure_opts *opts)
> +{
> +	struct cdns_dphy *dphy = phy_get_drvdata(phy);
> +	struct cdns_dphy_cfg cfg = { 0 };
> +	int ret;
> +
> +	ret = cdns_dphy_config_from_opts(phy, &opts->mipi_dphy, &cfg);
> +	if (ret)
> +		return ret;
> +
> +	/*
> +	 * Configure the internal PSM clk divider so that the DPHY has a
> +	 * 1MHz clk (or something close).
> +	 */
> +	ret = cdns_dphy_setup_psm(dphy);
> +	if (ret)
> +		return ret;
> +
> +	/*
> +	 * Configure attach clk lanes to data lanes: the DPHY has 2 clk lanes
> +	 * and 8 data lanes, each clk lane can be attache different set of
> +	 * data lanes. The 2 groups are named 'left' and 'right', so here we
> +	 * just say that we want the 'left' clk lane to drive the 'left' data
> +	 * lanes.
> +	 */
> +	cdns_dphy_set_clk_lane_cfg(dphy, DPHY_CLK_CFG_LEFT_DRIVES_LEFT);
> +
> +	/*
> +	 * Configure the DPHY PLL that will be used to generate the TX byte
> +	 * clk.
> +	 */
> +	cdns_dphy_set_pll_cfg(dphy, &cfg);
> +
> +	return 0;
> +}
> +
> +static int cdns_dphy_power_on(struct phy *phy)
> +{
> +	struct cdns_dphy *dphy = phy_get_drvdata(phy);
> +
> +	/* Start TX state machine. */
> +	writel(DPHY_CMN_SSM_EN | DPHY_CMN_TX_MODE_EN, dphy->regs + DPHY_CMN_SSM);
> +
> +	return 0;
> +}
> +
> +static int cdns_dphy_exit(struct phy *phy)
> +{
> +	struct cdns_dphy *dphy = phy_get_drvdata(phy);
> +
> +	clk_disable_unprepare(dphy->pll_ref_clk);
> +	clk_disable_unprepare(dphy->psm_clk);

Wouldn't this belong to power_off() (and enabling the clocks to
power_on())?

> +
> +	return 0;
> +}
> +
> +static struct phy_ops cdns_dphy_ops = {

const

> +	.configure	= cdns_dphy_configure,
> +	.validate	= cdns_dphy_validate,
> +	.power_on	= cdns_dphy_power_on,

How does it stop? Or does it? :-)

> +	.init		= cdns_dphy_init,

It'd be nice to maintain the order the same as in here (unless there are
reasons to do otherwise, of course).

> +	.exit		= cdns_dphy_exit,
> +};
> +
> +static int cdns_dphy_probe(struct platform_device *pdev)
> +{
> +	struct phy_provider *phy_provider;
> +	struct cdns_dphy *dphy;
> +	struct resource *res;
> +	int ret;
> +
> +	dphy = devm_kzalloc(&pdev->dev, sizeof(*dphy), GFP_KERNEL);
> +	if (!dphy)
> +		return -ENOMEM;
> +	dev_set_drvdata(&pdev->dev, dphy);
> +
> +	dphy->ops = of_device_get_match_data(&pdev->dev);
> +	if (!dphy->ops)
> +		return -EINVAL;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	dphy->regs = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(dphy->regs))
> +		return PTR_ERR(dphy->regs);
> +
> +	dphy->psm_clk = devm_clk_get(&pdev->dev, "psm");
> +	if (IS_ERR(dphy->psm_clk))
> +		return PTR_ERR(dphy->psm_clk);
> +
> +	dphy->pll_ref_clk = devm_clk_get(&pdev->dev, "pll_ref");
> +	if (IS_ERR(dphy->pll_ref_clk))
> +		return PTR_ERR(dphy->pll_ref_clk);
> +
> +	if (dphy->ops->probe) {

You could declare ret here. Entirely up to you.

> +		ret = dphy->ops->probe(dphy);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	dphy->phy = devm_phy_create(&pdev->dev, NULL, &cdns_dphy_ops);
> +	if (IS_ERR(dphy->phy)) {
> +		dev_err(&pdev->dev, "failed to create PHY\n");
> +		return PTR_ERR(dphy->phy);

Would it be appropriate to call the remove callback here?

> +	}
> +
> +	phy_set_drvdata(dphy->phy, dphy);
> +	phy_provider = devm_of_phy_provider_register(&pdev->dev, of_phy_simple_xlate);
> +
> +	return PTR_ERR_OR_ZERO(phy_provider);
> +}
> +
> +static int cdns_dphy_remove(struct platform_device *pdev)
> +{
> +	struct cdns_dphy *dphy = dev_get_drvdata(&pdev->dev);
> +
> +	if (dphy->ops->remove)
> +		dphy->ops->remove(dphy);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id cdns_dphy_of_match[] = {
> +	{ .compatible = "cdns,dphy", .data = &ref_dphy_ops },
> +	{ /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, cdns_dphy_of_match);
> +
> +static struct platform_driver cdns_dphy_platform_driver = {
> +	.probe		= cdns_dphy_probe,
> +	.remove		= cdns_dphy_remove,
> +	.driver		= {
> +		.name		= "cdns-mipi-dphy",
> +		.of_match_table	= cdns_dphy_of_match,
> +	},
> +};
> +module_platform_driver(cdns_dphy_platform_driver);
> +
> +MODULE_AUTHOR("Maxime Ripard <maxime.ripard@bootlin>");

bootlin.com ?

> +MODULE_DESCRIPTION("Cadence MIPI D-PHY Driver");
> +MODULE_LICENSE("GPL");
Kishon Vijay Abraham I - Nov. 20, 2018, 5:32 a.m.
Hi,

On 12/11/18 3:21 PM, Kishon Vijay Abraham I wrote:
> Hi Maxime,
> 
> On 06/11/18 8:24 PM, Maxime Ripard wrote:
>> Cadence has designed a D-PHY that can be used by the, currently in tree,
>> DSI bridge (DRM), CSI Transceiver and CSI Receiver (v4l2) drivers.
>>
>> Only the DSI driver has an ad-hoc driver for that phy at the moment, while
>> the v4l2 drivers are completely missing any phy support. In order to make
>> that phy support available to all these drivers, without having to
>> duplicate that code three times, let's create a generic phy framework
>> driver.
>>
>> Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
>> ---
>>   Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt |  21 +-
>>   Documentation/devicetree/bindings/phy/cdns,dphy.txt           |  20 +-
>>   drivers/phy/cadence/Kconfig                                   |  13 +-
>>   drivers/phy/cadence/Makefile                                  |   1 +-
>>   drivers/phy/cadence/cdns-dphy.c                               | 459 +++++++-
>>   5 files changed, 492 insertions(+), 22 deletions(-)
>>   create mode 100644 Documentation/devicetree/bindings/phy/cdns,dphy.txt
>>   create mode 100644 drivers/phy/cadence/cdns-dphy.c
>>
>> diff --git a/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt b/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt
>> index f5725bb6c61c..525a4bfd8634 100644
>> --- a/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt
>> +++ b/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt
>> @@ -31,28 +31,7 @@ Required subnodes:
>>   - one subnode per DSI device connected on the DSI bus. Each DSI device should
>>     contain a reg property encoding its virtual channel.
>>   
>> -Cadence DPHY
>> -============
>> -
>> -Cadence DPHY block.
>> -
>> -Required properties:
>> -- compatible: should be set to "cdns,dphy".
>> -- reg: physical base address and length of the DPHY registers.
>> -- clocks: DPHY reference clocks.
>> -- clock-names: must contain "psm" and "pll_ref".
>> -- #phy-cells: must be set to 0.
>> -
>> -
>>   Example:
>> -	dphy0: dphy@fd0e0000{
>> -		compatible = "cdns,dphy";
>> -		reg = <0x0 0xfd0e0000 0x0 0x1000>;
>> -		clocks = <&psm_clk>, <&pll_ref_clk>;
>> -		clock-names = "psm", "pll_ref";
>> -		#phy-cells = <0>;
>> -	};
>> -
>>   	dsi0: dsi@fd0c0000 {
>>   		compatible = "cdns,dsi";
>>   		reg = <0x0 0xfd0c0000 0x0 0x1000>;
>> diff --git a/Documentation/devicetree/bindings/phy/cdns,dphy.txt b/Documentation/devicetree/bindings/phy/cdns,dphy.txt
>> new file mode 100644
>> index 000000000000..1095bc4e72d9
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/phy/cdns,dphy.txt
>> @@ -0,0 +1,20 @@
>> +Cadence DPHY
>> +============
>> +
>> +Cadence DPHY block.
>> +
>> +Required properties:
>> +- compatible: should be set to "cdns,dphy".
>> +- reg: physical base address and length of the DPHY registers.
>> +- clocks: DPHY reference clocks.
>> +- clock-names: must contain "psm" and "pll_ref".
>> +- #phy-cells: must be set to 0.
>> +
>> +Example:
>> +	dphy0: dphy@fd0e0000{
>> +		compatible = "cdns,dphy";
>> +		reg = <0x0 0xfd0e0000 0x0 0x1000>;
>> +		clocks = <&psm_clk>, <&pll_ref_clk>;
>> +		clock-names = "psm", "pll_ref";
>> +		#phy-cells = <0>;
>> +	};
>> diff --git a/drivers/phy/cadence/Kconfig b/drivers/phy/cadence/Kconfig
>> index 57fff7de4031..240effa81046 100644
>> --- a/drivers/phy/cadence/Kconfig
>> +++ b/drivers/phy/cadence/Kconfig
>> @@ -1,6 +1,7 @@
>>   #
>> -# Phy driver for Cadence MHDP DisplayPort controller
>> +# Phy drivers for Cadence IPs
>>   #
>> +
>>   config PHY_CADENCE_DP
>>   	tristate "Cadence MHDP DisplayPort PHY driver"
>>   	depends on OF
>> @@ -8,3 +9,13 @@ config PHY_CADENCE_DP
>>   	select GENERIC_PHY
>>   	help
>>   	  Support for Cadence MHDP DisplayPort PHY.
>> +
>> +config PHY_CADENCE_DPHY
>> +	tristate "Cadence D-PHY Support"
>> +	depends on HAS_IOMEM && OF
>> +	select GENERIC_PHY
>> +	select GENERIC_PHY_MIPI_DPHY
>> +	help
>> +	  Choose this option if you have a Cadence D-PHY in your
>> +	  system. If M is selected, the module will be called
>> +	  cdns-csi.
>> diff --git a/drivers/phy/cadence/Makefile b/drivers/phy/cadence/Makefile
>> index e5b0a11cf28a..64cb9ea66ceb 100644
>> --- a/drivers/phy/cadence/Makefile
>> +++ b/drivers/phy/cadence/Makefile
>> @@ -1 +1,2 @@
>>   obj-$(CONFIG_PHY_CADENCE_DP)	+= phy-cadence-dp.o
>> +obj-$(CONFIG_PHY_CADENCE_DPHY)	+= cdns-dphy.o
>> diff --git a/drivers/phy/cadence/cdns-dphy.c b/drivers/phy/cadence/cdns-dphy.c
>> new file mode 100644
>> index 000000000000..a398b401e5d3
>> --- /dev/null
>> +++ b/drivers/phy/cadence/cdns-dphy.c
>> @@ -0,0 +1,459 @@
>> +// SPDX-License-Identifier: GPL-2.0+
>> +/*
>> + * Copyright: 2017-2018 Cadence Design Systems, Inc.
>> + */
>> +
>> +#include <linux/bitops.h>
>> +#include <linux/clk.h>
>> +#include <linux/io.h>
>> +#include <linux/module.h>
>> +#include <linux/of_address.h>
>> +#include <linux/of_device.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/reset.h>
>> +
>> +#include <linux/phy/phy.h>
>> +#include <linux/phy/phy-mipi-dphy.h>
>> +
>> +#define REG_WAKEUP_TIME_NS		800
>> +#define DPHY_PLL_RATE_HZ		108000000
>> +
>> +/* DPHY registers */
>> +#define DPHY_PMA_CMN(reg)		(reg)
>> +#define DPHY_PMA_LCLK(reg)		(0x100 + (reg))
>> +#define DPHY_PMA_LDATA(lane, reg)	(0x200 + ((lane) * 0x100) + (reg))
>> +#define DPHY_PMA_RCLK(reg)		(0x600 + (reg))
>> +#define DPHY_PMA_RDATA(lane, reg)	(0x700 + ((lane) * 0x100) + (reg))
>> +#define DPHY_PCS(reg)			(0xb00 + (reg))
>> +
>> +#define DPHY_CMN_SSM			DPHY_PMA_CMN(0x20)
>> +#define DPHY_CMN_SSM_EN			BIT(0)
>> +#define DPHY_CMN_TX_MODE_EN		BIT(9)
>> +
>> +#define DPHY_CMN_PWM			DPHY_PMA_CMN(0x40)
>> +#define DPHY_CMN_PWM_DIV(x)		((x) << 20)
>> +#define DPHY_CMN_PWM_LOW(x)		((x) << 10)
>> +#define DPHY_CMN_PWM_HIGH(x)		(x)
>> +
>> +#define DPHY_CMN_FBDIV			DPHY_PMA_CMN(0x4c)
>> +#define DPHY_CMN_FBDIV_VAL(low, high)	(((high) << 11) | ((low) << 22))
>> +#define DPHY_CMN_FBDIV_FROM_REG		(BIT(10) | BIT(21))
>> +
>> +#define DPHY_CMN_OPIPDIV		DPHY_PMA_CMN(0x50)
>> +#define DPHY_CMN_IPDIV_FROM_REG		BIT(0)
>> +#define DPHY_CMN_IPDIV(x)		((x) << 1)
>> +#define DPHY_CMN_OPDIV_FROM_REG		BIT(6)
>> +#define DPHY_CMN_OPDIV(x)		((x) << 7)
>> +
>> +#define DPHY_PSM_CFG			DPHY_PCS(0x4)
>> +#define DPHY_PSM_CFG_FROM_REG		BIT(0)
>> +#define DPHY_PSM_CLK_DIV(x)		((x) << 1)
>> +
>> +#define DSI_HBP_FRAME_OVERHEAD		12
>> +#define DSI_HSA_FRAME_OVERHEAD		14
>> +#define DSI_HFP_FRAME_OVERHEAD		6
>> +#define DSI_HSS_VSS_VSE_FRAME_OVERHEAD	4
>> +#define DSI_BLANKING_FRAME_OVERHEAD	6
>> +#define DSI_NULL_FRAME_OVERHEAD		6
>> +#define DSI_EOT_PKT_SIZE		4
>> +
>> +struct cdns_dphy_cfg {
>> +	u8 pll_ipdiv;
>> +	u8 pll_opdiv;
>> +	u16 pll_fbdiv;
>> +	unsigned int nlanes;
>> +};
>> +
>> +enum cdns_dphy_clk_lane_cfg {
>> +	DPHY_CLK_CFG_LEFT_DRIVES_ALL = 0,
>> +	DPHY_CLK_CFG_LEFT_DRIVES_RIGHT = 1,
>> +	DPHY_CLK_CFG_LEFT_DRIVES_LEFT = 2,
>> +	DPHY_CLK_CFG_RIGHT_DRIVES_ALL = 3,
>> +};
>> +
>> +struct cdns_dphy;
>> +struct cdns_dphy_ops {
>> +	int (*probe)(struct cdns_dphy *dphy);
>> +	void (*remove)(struct cdns_dphy *dphy);
>> +	void (*set_psm_div)(struct cdns_dphy *dphy, u8 div);
>> +	void (*set_clk_lane_cfg)(struct cdns_dphy *dphy,
>> +				 enum cdns_dphy_clk_lane_cfg cfg);
>> +	void (*set_pll_cfg)(struct cdns_dphy *dphy,
>> +			    const struct cdns_dphy_cfg *cfg);
>> +	unsigned long (*get_wakeup_time_ns)(struct cdns_dphy *dphy);
>> +};
>> +
>> +struct cdns_dphy {
>> +	struct cdns_dphy_cfg cfg;
>> +	void __iomem *regs;
>> +	struct clk *psm_clk;
>> +	struct clk *pll_ref_clk;
>> +	const struct cdns_dphy_ops *ops;
>> +	struct phy *phy;
>> +};
>> +
>> +static int cdns_dsi_get_dphy_pll_cfg(struct cdns_dphy *dphy,
>> +				     struct cdns_dphy_cfg *cfg,
>> +				     struct phy_configure_opts_mipi_dphy *opts,
>> +				     unsigned int *dsi_hfp_ext)
>> +{
>> +	u64 dlane_bps, dlane_bps_max, fbdiv, fbdiv_max, adj_dsi_htotal;
>> +	unsigned long pll_ref_hz = clk_get_rate(dphy->pll_ref_clk);
>> +
>> +	memset(cfg, 0, sizeof(*cfg));
>> +
>> +	if (pll_ref_hz < 9600000 || pll_ref_hz >= 150000000)
>> +		return -EINVAL;
>> +	else if (pll_ref_hz < 19200000)
>> +		cfg->pll_ipdiv = 1;
>> +	else if (pll_ref_hz < 38400000)
>> +		cfg->pll_ipdiv = 2;
>> +	else if (pll_ref_hz < 76800000)
>> +		cfg->pll_ipdiv = 4;
>> +	else
>> +		cfg->pll_ipdiv = 8;
>> +
>> +	dlane_bps = opts->hs_clk_rate;
>> +
>> +	if (dlane_bps > 2500000000UL || dlane_bps < 160000000UL)
>> +		return -EINVAL;
>> +	else if (dlane_bps >= 1250000000)
>> +		cfg->pll_opdiv = 1;
>> +	else if (dlane_bps >= 630000000)
>> +		cfg->pll_opdiv = 2;
>> +	else if (dlane_bps >= 320000000)
>> +		cfg->pll_opdiv = 4;
>> +	else if (dlane_bps >= 160000000)
>> +		cfg->pll_opdiv = 8;
>> +
>> +	/*
>> +	 * Allow a deviation of 0.2% on the per-lane data rate to try to
>> +	 * recover a potential mismatch between DPI and PPI clks.
>> +	 */
>> +	dlane_bps_max = dlane_bps + DIV_ROUND_DOWN_ULL(dlane_bps, 500);
>> +	fbdiv_max = DIV_ROUND_DOWN_ULL(dlane_bps_max * 2 *
>> +				       cfg->pll_opdiv * cfg->pll_ipdiv,
>> +				       pll_ref_hz);
>> +	fbdiv = DIV_ROUND_UP_ULL(dlane_bps * 2 * cfg->pll_opdiv *
>> +				 cfg->pll_ipdiv,
>> +				 pll_ref_hz);
>> +
>> +	/*
>> +	 * Iterate over all acceptable fbdiv and try to find an adjusted DSI
>> +	 * htotal length providing an exact match.
>> +	 *
>> +	 * Note that we could do something even trickier by relying on the fact
>> +	 * that a new line is not necessarily aligned on a lane boundary, so,
>> +	 * by making adj_dsi_htotal non aligned on a dsi_lanes we can improve a
>> +	 * bit the precision. With this, the step would be
>> +	 *
>> +	 *	pll_ref_hz / (2 * opdiv * ipdiv * nlanes)
>> +	 *
>> +	 * instead of
>> +	 *
>> +	 *	pll_ref_hz / (2 * opdiv * ipdiv)
>> +	 *
>> +	 * The drawback of this approach is that we would need to make sure the
>> +	 * number or lines is a multiple of the realignment periodicity which is
>> +	 * a function of the number of lanes and the original misalignment. For
>> +	 * example, for NLANES = 4 and HTOTAL % NLANES = 3, it takes 4 lines
>> +	 * to realign on a lane:
>> +	 * LINE 0: expected number of bytes, starts emitting first byte of
>> +	 *	   LINE 1 on LANE 3
>> +	 * LINE 1: expected number of bytes, starts emitting first 2 bytes of
>> +	 *	   LINE 2 on LANES 2 and 3
>> +	 * LINE 2: expected number of bytes, starts emitting first 3 bytes of
>> +	 *	   of LINE 3 on LANES 1, 2 and 3
>> +	 * LINE 3: one byte less, now things are realigned on LANE 0 for LINE 4
>> +	 *
>> +	 * I figured this extra complexity was not worth the benefit, but if
>> +	 * someone really has unfixable mismatch, that would be something to
>> +	 * investigate.
>> +	 */
>> +	for (; fbdiv <= fbdiv_max; fbdiv++) {
>> +		u32 rem;
>> +
>> +		/*
>> +		 * Do the division in 2 steps to avoid an overflow on the
>> +		 * divider.
>> +		 */
>> +		rem = do_div(adj_dsi_htotal, opts->hs_clk_rate);
>> +		if (rem)
>> +			continue;
>> +
>> +		rem = do_div(adj_dsi_htotal,
>> +			     cfg->pll_opdiv * cfg->pll_ipdiv * 2 * 8);
>> +		if (rem)
>> +			continue;
>> +
>> +		cfg->pll_fbdiv = fbdiv;
>> +		break;
>> +	}
>> +
>> +	/* No match, let's just reject the display mode. */
>> +	if (!cfg->pll_fbdiv)
>> +		return -EINVAL;
>> +
>> +	return 0;
>> +}
>> +
>> +static int cdns_dphy_setup_psm(struct cdns_dphy *dphy)
>> +{
>> +	unsigned long psm_clk_hz = clk_get_rate(dphy->psm_clk);
>> +	unsigned long psm_div;
>> +
>> +	if (!psm_clk_hz || psm_clk_hz > 100000000)
>> +		return -EINVAL;
>> +
>> +	psm_div = DIV_ROUND_CLOSEST(psm_clk_hz, 1000000);
>> +	if (dphy->ops->set_psm_div)
>> +		dphy->ops->set_psm_div(dphy, psm_div);
>> +
>> +	return 0;
>> +}
>> +
>> +static void cdns_dphy_set_clk_lane_cfg(struct cdns_dphy *dphy,
>> +				       enum cdns_dphy_clk_lane_cfg cfg)
>> +{
>> +	if (dphy->ops->set_clk_lane_cfg)
>> +		dphy->ops->set_clk_lane_cfg(dphy, cfg);
>> +}
>> +
>> +static void cdns_dphy_set_pll_cfg(struct cdns_dphy *dphy,
>> +				  const struct cdns_dphy_cfg *cfg)
>> +{
>> +	if (dphy->ops->set_pll_cfg)
>> +		dphy->ops->set_pll_cfg(dphy, cfg);
>> +}
>> +
>> +static unsigned long cdns_dphy_get_wakeup_time_ns(struct cdns_dphy *dphy)
>> +{
>> +	return dphy->ops->get_wakeup_time_ns(dphy);
>> +}
>> +
>> +static unsigned long cdns_dphy_ref_get_wakeup_time_ns(struct cdns_dphy *dphy)
>> +{
>> +	/* Default wakeup time is 800 ns (in a simulated environment). */
>> +	return 800;
>> +}
>> +
>> +static void cdns_dphy_ref_set_pll_cfg(struct cdns_dphy *dphy,
>> +				      const struct cdns_dphy_cfg *cfg)
>> +{
>> +	u32 fbdiv_low, fbdiv_high;
>> +
>> +	fbdiv_low = (cfg->pll_fbdiv / 4) - 2;
>> +	fbdiv_high = cfg->pll_fbdiv - fbdiv_low - 2;
>> +
>> +	writel(DPHY_CMN_IPDIV_FROM_REG | DPHY_CMN_OPDIV_FROM_REG |
>> +	       DPHY_CMN_IPDIV(cfg->pll_ipdiv) |
>> +	       DPHY_CMN_OPDIV(cfg->pll_opdiv),
>> +	       dphy->regs + DPHY_CMN_OPIPDIV);
>> +	writel(DPHY_CMN_FBDIV_FROM_REG |
>> +	       DPHY_CMN_FBDIV_VAL(fbdiv_low, fbdiv_high),
>> +	       dphy->regs + DPHY_CMN_FBDIV);
>> +	writel(DPHY_CMN_PWM_HIGH(6) | DPHY_CMN_PWM_LOW(0x101) |
>> +	       DPHY_CMN_PWM_DIV(0x8),
>> +	       dphy->regs + DPHY_CMN_PWM);
>> +}
>> +
>> +static void cdns_dphy_ref_set_psm_div(struct cdns_dphy *dphy, u8 div)
>> +{
>> +	writel(DPHY_PSM_CFG_FROM_REG | DPHY_PSM_CLK_DIV(div),
>> +	       dphy->regs + DPHY_PSM_CFG);
>> +}
>> +
>> +/*
>> + * This is the reference implementation of DPHY hooks. Specific integration of
>> + * this IP may have to re-implement some of them depending on how they decided
>> + * to wire things in the SoC.
>> + */
>> +static const struct cdns_dphy_ops ref_dphy_ops = {
>> +	.get_wakeup_time_ns = cdns_dphy_ref_get_wakeup_time_ns,
>> +	.set_pll_cfg = cdns_dphy_ref_set_pll_cfg,
>> +	.set_psm_div = cdns_dphy_ref_set_psm_div,
>> +};
>> +
>> +static int cdns_dphy_config_from_opts(struct phy *phy,
>> +				      struct phy_configure_opts_mipi_dphy *opts,
>> +				      struct cdns_dphy_cfg *cfg)
>> +{
>> +	struct cdns_dphy *dphy = phy_get_drvdata(phy);
>> +	unsigned int dsi_hfp_ext = 0;
>> +	int ret;
>> +
>> +	ret = phy_mipi_dphy_config_validate(opts);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = cdns_dsi_get_dphy_pll_cfg(dphy, cfg,
>> +					opts, &dsi_hfp_ext);
>> +	if (ret)
>> +		return ret;
>> +
>> +	opts->wakeup = cdns_dphy_get_wakeup_time_ns(dphy);

Is the wakeup populated here used by the consumer driver?

Thanks
Kishon
Maxime Ripard - Nov. 21, 2018, 10:11 a.m.
Hi Kishon,

On Tue, Nov 20, 2018 at 11:02:34AM +0530, Kishon Vijay Abraham I wrote:
> > > +static int cdns_dphy_config_from_opts(struct phy *phy,
> > > +				      struct phy_configure_opts_mipi_dphy *opts,
> > > +				      struct cdns_dphy_cfg *cfg)
> > > +{
> > > +	struct cdns_dphy *dphy = phy_get_drvdata(phy);
> > > +	unsigned int dsi_hfp_ext = 0;
> > > +	int ret;
> > > +
> > > +	ret = phy_mipi_dphy_config_validate(opts);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	ret = cdns_dsi_get_dphy_pll_cfg(dphy, cfg,
> > > +					opts, &dsi_hfp_ext);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	opts->wakeup = cdns_dphy_get_wakeup_time_ns(dphy);
> 
> Is the wakeup populated here used by the consumer driver?

It's supposed to, if it can yes.

Maxime
Kishon Vijay Abraham I - Nov. 21, 2018, 10:29 a.m.
Hi Maxime,

On 21/11/18 3:41 PM, Maxime Ripard wrote:
> Hi Kishon,
> 
> On Tue, Nov 20, 2018 at 11:02:34AM +0530, Kishon Vijay Abraham I wrote:
>>>> +static int cdns_dphy_config_from_opts(struct phy *phy,
>>>> +				      struct phy_configure_opts_mipi_dphy *opts,
>>>> +				      struct cdns_dphy_cfg *cfg)
>>>> +{
>>>> +	struct cdns_dphy *dphy = phy_get_drvdata(phy);
>>>> +	unsigned int dsi_hfp_ext = 0;
>>>> +	int ret;
>>>> +
>>>> +	ret = phy_mipi_dphy_config_validate(opts);
>>>> +	if (ret)
>>>> +		return ret;
>>>> +
>>>> +	ret = cdns_dsi_get_dphy_pll_cfg(dphy, cfg,
>>>> +					opts, &dsi_hfp_ext);
>>>> +	if (ret)
>>>> +		return ret;
>>>> +
>>>> +	opts->wakeup = cdns_dphy_get_wakeup_time_ns(dphy);
>>
>> Is the wakeup populated here used by the consumer driver?
> 
> It's supposed to, if it can yes.

But I guess right now it's not using. I'm thinking the usefulness of validate
callback (only from this series point of view). Why should a consumer driver
invoke validate if it doesn't intend to configure the PHY?

The 3 steps required are
	* The consumer driver gets the default config
	* The consumer driver changes some of the configuration and
	* The consumer driver invokes phy configure callback.

phy_configure anyways can validate the config before actually configuring the phy.

Thanks
Kishon
Maxime Ripard - Nov. 21, 2018, 1:21 p.m.
Hi Sakari,

On Mon, Nov 19, 2018 at 11:24:20PM +0200, Sakari Ailus wrote:
> Hi Maxime,
> 
> On Tue, Nov 06, 2018 at 03:54:20PM +0100, Maxime Ripard wrote:
> > Cadence has designed a D-PHY that can be used by the, currently in tree,
> > DSI bridge (DRM), CSI Transceiver and CSI Receiver (v4l2) drivers.
> > 
> > Only the DSI driver has an ad-hoc driver for that phy at the moment, while
> > the v4l2 drivers are completely missing any phy support. In order to make
> > that phy support available to all these drivers, without having to
> > duplicate that code three times, let's create a generic phy framework
> > driver.
> > 
> > Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
> > ---
> >  Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt |  21 +-
> >  Documentation/devicetree/bindings/phy/cdns,dphy.txt           |  20 +-
> 
> Coould you split out the DT binding changes into a separate patch?

Will do.

> >  drivers/phy/cadence/Kconfig                                   |  13 +-
> >  drivers/phy/cadence/Makefile                                  |   1 +-
> >  drivers/phy/cadence/cdns-dphy.c                               | 459 +++++++-
> >  5 files changed, 492 insertions(+), 22 deletions(-)
> >  create mode 100644 Documentation/devicetree/bindings/phy/cdns,dphy.txt
> >  create mode 100644 drivers/phy/cadence/cdns-dphy.c
> > 
> > diff --git a/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt b/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt
> > index f5725bb6c61c..525a4bfd8634 100644
> > --- a/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt
> > +++ b/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt
> > @@ -31,28 +31,7 @@ Required subnodes:
> >  - one subnode per DSI device connected on the DSI bus. Each DSI device should
> >    contain a reg property encoding its virtual channel.
> >  
> > -Cadence DPHY
> > -============
> > -
> > -Cadence DPHY block.
> > -
> > -Required properties:
> > -- compatible: should be set to "cdns,dphy".
> > -- reg: physical base address and length of the DPHY registers.
> > -- clocks: DPHY reference clocks.
> > -- clock-names: must contain "psm" and "pll_ref".
> > -- #phy-cells: must be set to 0.
> > -
> > -
> >  Example:
> > -	dphy0: dphy@fd0e0000{
> > -		compatible = "cdns,dphy";
> > -		reg = <0x0 0xfd0e0000 0x0 0x1000>;
> > -		clocks = <&psm_clk>, <&pll_ref_clk>;
> > -		clock-names = "psm", "pll_ref";
> > -		#phy-cells = <0>;
> > -	};
> > -
> >  	dsi0: dsi@fd0c0000 {
> >  		compatible = "cdns,dsi";
> >  		reg = <0x0 0xfd0c0000 0x0 0x1000>;
> > diff --git a/Documentation/devicetree/bindings/phy/cdns,dphy.txt b/Documentation/devicetree/bindings/phy/cdns,dphy.txt
> > new file mode 100644
> > index 000000000000..1095bc4e72d9
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/phy/cdns,dphy.txt
> > @@ -0,0 +1,20 @@
> > +Cadence DPHY
> > +============
> > +
> > +Cadence DPHY block.
> > +
> > +Required properties:
> > +- compatible: should be set to "cdns,dphy".
> > +- reg: physical base address and length of the DPHY registers.
> > +- clocks: DPHY reference clocks.
> > +- clock-names: must contain "psm" and "pll_ref".
> > +- #phy-cells: must be set to 0.
> > +
> > +Example:
> > +	dphy0: dphy@fd0e0000{
> > +		compatible = "cdns,dphy";
> > +		reg = <0x0 0xfd0e0000 0x0 0x1000>;
> > +		clocks = <&psm_clk>, <&pll_ref_clk>;
> > +		clock-names = "psm", "pll_ref";
> > +		#phy-cells = <0>;
> > +	};
> > diff --git a/drivers/phy/cadence/Kconfig b/drivers/phy/cadence/Kconfig
> > index 57fff7de4031..240effa81046 100644
> > --- a/drivers/phy/cadence/Kconfig
> > +++ b/drivers/phy/cadence/Kconfig
> > @@ -1,6 +1,7 @@
> >  #
> > -# Phy driver for Cadence MHDP DisplayPort controller
> > +# Phy drivers for Cadence IPs
> >  #
> > +
> >  config PHY_CADENCE_DP
> >  	tristate "Cadence MHDP DisplayPort PHY driver"
> >  	depends on OF
> > @@ -8,3 +9,13 @@ config PHY_CADENCE_DP
> >  	select GENERIC_PHY
> >  	help
> >  	  Support for Cadence MHDP DisplayPort PHY.
> > +
> > +config PHY_CADENCE_DPHY
> > +	tristate "Cadence D-PHY Support"
> > +	depends on HAS_IOMEM && OF
> > +	select GENERIC_PHY
> > +	select GENERIC_PHY_MIPI_DPHY
> > +	help
> > +	  Choose this option if you have a Cadence D-PHY in your
> > +	  system. If M is selected, the module will be called
> > +	  cdns-csi.
> > diff --git a/drivers/phy/cadence/Makefile b/drivers/phy/cadence/Makefile
> > index e5b0a11cf28a..64cb9ea66ceb 100644
> > --- a/drivers/phy/cadence/Makefile
> > +++ b/drivers/phy/cadence/Makefile
> > @@ -1 +1,2 @@
> >  obj-$(CONFIG_PHY_CADENCE_DP)	+= phy-cadence-dp.o
> > +obj-$(CONFIG_PHY_CADENCE_DPHY)	+= cdns-dphy.o
> > diff --git a/drivers/phy/cadence/cdns-dphy.c b/drivers/phy/cadence/cdns-dphy.c
> > new file mode 100644
> > index 000000000000..a398b401e5d3
> > --- /dev/null
> > +++ b/drivers/phy/cadence/cdns-dphy.c
> > @@ -0,0 +1,459 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright: 2017-2018 Cadence Design Systems, Inc.
> > + */
> > +
> > +#include <linux/bitops.h>
> > +#include <linux/clk.h>
> > +#include <linux/io.h>
> > +#include <linux/module.h>
> > +#include <linux/of_address.h>
> > +#include <linux/of_device.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/reset.h>
> > +
> > +#include <linux/phy/phy.h>
> > +#include <linux/phy/phy-mipi-dphy.h>
> > +
> > +#define REG_WAKEUP_TIME_NS		800
> > +#define DPHY_PLL_RATE_HZ		108000000
> > +
> > +/* DPHY registers */
> > +#define DPHY_PMA_CMN(reg)		(reg)
> > +#define DPHY_PMA_LCLK(reg)		(0x100 + (reg))
> > +#define DPHY_PMA_LDATA(lane, reg)	(0x200 + ((lane) * 0x100) + (reg))
> > +#define DPHY_PMA_RCLK(reg)		(0x600 + (reg))
> > +#define DPHY_PMA_RDATA(lane, reg)	(0x700 + ((lane) * 0x100) + (reg))
> > +#define DPHY_PCS(reg)			(0xb00 + (reg))
> > +
> > +#define DPHY_CMN_SSM			DPHY_PMA_CMN(0x20)
> > +#define DPHY_CMN_SSM_EN			BIT(0)
> > +#define DPHY_CMN_TX_MODE_EN		BIT(9)
> > +
> > +#define DPHY_CMN_PWM			DPHY_PMA_CMN(0x40)
> > +#define DPHY_CMN_PWM_DIV(x)		((x) << 20)
> > +#define DPHY_CMN_PWM_LOW(x)		((x) << 10)
> > +#define DPHY_CMN_PWM_HIGH(x)		(x)
> > +
> > +#define DPHY_CMN_FBDIV			DPHY_PMA_CMN(0x4c)
> > +#define DPHY_CMN_FBDIV_VAL(low, high)	(((high) << 11) | ((low) << 22))
> > +#define DPHY_CMN_FBDIV_FROM_REG		(BIT(10) | BIT(21))
> > +
> > +#define DPHY_CMN_OPIPDIV		DPHY_PMA_CMN(0x50)
> > +#define DPHY_CMN_IPDIV_FROM_REG		BIT(0)
> > +#define DPHY_CMN_IPDIV(x)		((x) << 1)
> > +#define DPHY_CMN_OPDIV_FROM_REG		BIT(6)
> > +#define DPHY_CMN_OPDIV(x)		((x) << 7)
> > +
> > +#define DPHY_PSM_CFG			DPHY_PCS(0x4)
> > +#define DPHY_PSM_CFG_FROM_REG		BIT(0)
> > +#define DPHY_PSM_CLK_DIV(x)		((x) << 1)
> > +
> > +#define DSI_HBP_FRAME_OVERHEAD		12
> > +#define DSI_HSA_FRAME_OVERHEAD		14
> > +#define DSI_HFP_FRAME_OVERHEAD		6
> > +#define DSI_HSS_VSS_VSE_FRAME_OVERHEAD	4
> > +#define DSI_BLANKING_FRAME_OVERHEAD	6
> > +#define DSI_NULL_FRAME_OVERHEAD		6
> > +#define DSI_EOT_PKT_SIZE		4
> > +
> > +struct cdns_dphy_cfg {
> > +	u8 pll_ipdiv;
> > +	u8 pll_opdiv;
> > +	u16 pll_fbdiv;
> > +	unsigned int nlanes;
> > +};
> > +
> > +enum cdns_dphy_clk_lane_cfg {
> > +	DPHY_CLK_CFG_LEFT_DRIVES_ALL = 0,
> > +	DPHY_CLK_CFG_LEFT_DRIVES_RIGHT = 1,
> > +	DPHY_CLK_CFG_LEFT_DRIVES_LEFT = 2,
> > +	DPHY_CLK_CFG_RIGHT_DRIVES_ALL = 3,
> > +};
> > +
> > +struct cdns_dphy;
> > +struct cdns_dphy_ops {
> > +	int (*probe)(struct cdns_dphy *dphy);
> > +	void (*remove)(struct cdns_dphy *dphy);
> > +	void (*set_psm_div)(struct cdns_dphy *dphy, u8 div);
> > +	void (*set_clk_lane_cfg)(struct cdns_dphy *dphy,
> > +				 enum cdns_dphy_clk_lane_cfg cfg);
> > +	void (*set_pll_cfg)(struct cdns_dphy *dphy,
> > +			    const struct cdns_dphy_cfg *cfg);
> > +	unsigned long (*get_wakeup_time_ns)(struct cdns_dphy *dphy);
> > +};
> > +
> > +struct cdns_dphy {
> > +	struct cdns_dphy_cfg cfg;
> > +	void __iomem *regs;
> > +	struct clk *psm_clk;
> > +	struct clk *pll_ref_clk;
> > +	const struct cdns_dphy_ops *ops;
> > +	struct phy *phy;
> > +};
> > +
> > +static int cdns_dsi_get_dphy_pll_cfg(struct cdns_dphy *dphy,
> > +				     struct cdns_dphy_cfg *cfg,
> > +				     struct phy_configure_opts_mipi_dphy *opts,
> > +				     unsigned int *dsi_hfp_ext)
> > +{
> > +	u64 dlane_bps, dlane_bps_max, fbdiv, fbdiv_max, adj_dsi_htotal;
> > +	unsigned long pll_ref_hz = clk_get_rate(dphy->pll_ref_clk);
> > +
> > +	memset(cfg, 0, sizeof(*cfg));
> > +
> > +	if (pll_ref_hz < 9600000 || pll_ref_hz >= 150000000)
> > +		return -EINVAL;
> > +	else if (pll_ref_hz < 19200000)
> > +		cfg->pll_ipdiv = 1;
> > +	else if (pll_ref_hz < 38400000)
> > +		cfg->pll_ipdiv = 2;
> > +	else if (pll_ref_hz < 76800000)
> > +		cfg->pll_ipdiv = 4;
> > +	else
> > +		cfg->pll_ipdiv = 8;
> > +
> > +	dlane_bps = opts->hs_clk_rate;
> > +
> > +	if (dlane_bps > 2500000000UL || dlane_bps < 160000000UL)
> > +		return -EINVAL;
> > +	else if (dlane_bps >= 1250000000)
> > +		cfg->pll_opdiv = 1;
> > +	else if (dlane_bps >= 630000000)
> > +		cfg->pll_opdiv = 2;
> > +	else if (dlane_bps >= 320000000)
> > +		cfg->pll_opdiv = 4;
> > +	else if (dlane_bps >= 160000000)
> > +		cfg->pll_opdiv = 8;
> > +
> > +	/*
> > +	 * Allow a deviation of 0.2% on the per-lane data rate to try to
> > +	 * recover a potential mismatch between DPI and PPI clks.
> > +	 */
> > +	dlane_bps_max = dlane_bps + DIV_ROUND_DOWN_ULL(dlane_bps, 500);
> > +	fbdiv_max = DIV_ROUND_DOWN_ULL(dlane_bps_max * 2 *
> > +				       cfg->pll_opdiv * cfg->pll_ipdiv,
> > +				       pll_ref_hz);
> > +	fbdiv = DIV_ROUND_UP_ULL(dlane_bps * 2 * cfg->pll_opdiv *
> > +				 cfg->pll_ipdiv,
> > +				 pll_ref_hz);
> > +
> > +	/*
> > +	 * Iterate over all acceptable fbdiv and try to find an adjusted DSI
> > +	 * htotal length providing an exact match.
> > +	 *
> > +	 * Note that we could do something even trickier by relying on the fact
> > +	 * that a new line is not necessarily aligned on a lane boundary, so,
> > +	 * by making adj_dsi_htotal non aligned on a dsi_lanes we can improve a
> > +	 * bit the precision. With this, the step would be
> > +	 *
> > +	 *	pll_ref_hz / (2 * opdiv * ipdiv * nlanes)
> > +	 *
> > +	 * instead of
> > +	 *
> > +	 *	pll_ref_hz / (2 * opdiv * ipdiv)
> > +	 *
> > +	 * The drawback of this approach is that we would need to make sure the
> > +	 * number or lines is a multiple of the realignment periodicity which is
> > +	 * a function of the number of lanes and the original misalignment. For
> > +	 * example, for NLANES = 4 and HTOTAL % NLANES = 3, it takes 4 lines
> > +	 * to realign on a lane:
> > +	 * LINE 0: expected number of bytes, starts emitting first byte of
> > +	 *	   LINE 1 on LANE 3
> > +	 * LINE 1: expected number of bytes, starts emitting first 2 bytes of
> > +	 *	   LINE 2 on LANES 2 and 3
> > +	 * LINE 2: expected number of bytes, starts emitting first 3 bytes of
> > +	 *	   of LINE 3 on LANES 1, 2 and 3
> > +	 * LINE 3: one byte less, now things are realigned on LANE 0 for LINE 4
> > +	 *
> > +	 * I figured this extra complexity was not worth the benefit, but if
> > +	 * someone really has unfixable mismatch, that would be something to
> > +	 * investigate.
> > +	 */
> > +	for (; fbdiv <= fbdiv_max; fbdiv++) {
> > +		u32 rem;
> > +
> > +		/*
> > +		 * Do the division in 2 steps to avoid an overflow on the
> > +		 * divider.
> > +		 */
> > +		rem = do_div(adj_dsi_htotal, opts->hs_clk_rate);
> 
> Hmm. I don't see adj_dsi_htotal being set anywhere. I suppose that can't be
> intended.
> 
> > +		if (rem)
> > +			continue;
> > +
> > +		rem = do_div(adj_dsi_htotal,
> > +			     cfg->pll_opdiv * cfg->pll_ipdiv * 2 * 8);
> > +		if (rem)
> > +			continue;
> 
> Is fbdiv supposed to be used in the formula somewhere?

Hmmm, right. Something's fishy here.

> > +static int cdns_dphy_exit(struct phy *phy)
> > +{
> > +	struct cdns_dphy *dphy = phy_get_drvdata(phy);
> > +
> > +	clk_disable_unprepare(dphy->pll_ref_clk);
> > +	clk_disable_unprepare(dphy->psm_clk);
> 
> Wouldn't this belong to power_off() (and enabling the clocks to
> power_on())?

Yep, it would make more sense.

> > +
> > +	return 0;
> > +}
> > +
> > +static struct phy_ops cdns_dphy_ops = {
> 
> const
> 
> > +	.configure	= cdns_dphy_configure,
> > +	.validate	= cdns_dphy_validate,
> > +	.power_on	= cdns_dphy_power_on,
> 
> How does it stop? Or does it? :-)

It's only been run in a simulator so far, so I'm not sure "turn on"
and "turn off" are concepts that can apply to this driver at this
point :)

> > +	.init		= cdns_dphy_init,
> 
> It'd be nice to maintain the order the same as in here (unless there are
> reasons to do otherwise, of course).

What do you mean?

> > +		ret = dphy->ops->probe(dphy);
> > +		if (ret)
> > +			return ret;
> > +	}
> > +
> > +	dphy->phy = devm_phy_create(&pdev->dev, NULL, &cdns_dphy_ops);
> > +	if (IS_ERR(dphy->phy)) {
> > +		dev_err(&pdev->dev, "failed to create PHY\n");
> > +		return PTR_ERR(dphy->phy);
> 
> Would it be appropriate to call the remove callback here?

Definitely, I'll add it.

Thanks!
Maxime
Maxime Ripard - Nov. 21, 2018, 1:47 p.m.
Hi Kishon,

On Wed, Nov 21, 2018 at 03:59:43PM +0530, Kishon Vijay Abraham I wrote:
> On 21/11/18 3:41 PM, Maxime Ripard wrote:
> > Hi Kishon,
> > 
> > On Tue, Nov 20, 2018 at 11:02:34AM +0530, Kishon Vijay Abraham I wrote:
> >>>> +static int cdns_dphy_config_from_opts(struct phy *phy,
> >>>> +				      struct phy_configure_opts_mipi_dphy *opts,
> >>>> +				      struct cdns_dphy_cfg *cfg)
> >>>> +{
> >>>> +	struct cdns_dphy *dphy = phy_get_drvdata(phy);
> >>>> +	unsigned int dsi_hfp_ext = 0;
> >>>> +	int ret;
> >>>> +
> >>>> +	ret = phy_mipi_dphy_config_validate(opts);
> >>>> +	if (ret)
> >>>> +		return ret;
> >>>> +
> >>>> +	ret = cdns_dsi_get_dphy_pll_cfg(dphy, cfg,
> >>>> +					opts, &dsi_hfp_ext);
> >>>> +	if (ret)
> >>>> +		return ret;
> >>>> +
> >>>> +	opts->wakeup = cdns_dphy_get_wakeup_time_ns(dphy);
> >>
> >> Is the wakeup populated here used by the consumer driver?
> > 
> > It's supposed to, if it can yes.
> 
> But I guess right now it's not using. I'm thinking the usefulness of validate
> callback (only from this series point of view). Why should a consumer driver
> invoke validate if it doesn't intend to configure the PHY?
> 
> The 3 steps required are
> 	* The consumer driver gets the default config
> 	* The consumer driver changes some of the configuration and
> 	* The consumer driver invokes phy configure callback.
> 
> phy_configure anyways can validate the config before actually configuring the phy.

If you only want to configure the PHY, then yes, sure.

However, the point here is that validate helps negotiating what the
source device (DSI controller for example) and what the sink device
(say a panel) are capable of.

A panel for example might very well have multiple resolutions that it
supports, and the DSI controller will have some as well. And the PHY
will only be able to operate within certain boundaries too. However,
they don't necessarily match, since there's so many panels, and so
many SoCs.

Let's say our (very weird) panel is able to do 640x480, 1024x768 and
1280x800. Our DSI driver can only operate with 1024 pixels in both
dimensions, and the PHY can only reach the bus frequency needed for
around 800x600.

We'll want to filter out 1280x800 (because the DSI controller can't
provide that) and 1024x768 (because the PHY can go fast enough), to
only provide the 640x480 option to the user.

That's what validate bring you. The option to test whether a given
configuration *would* work, without actually wanting to apply it right
now.

Does that make sense?

Maxime
Kishon Vijay Abraham I - Nov. 22, 2018, 8:46 a.m.
Hi,

On 21/11/18 7:17 PM, Maxime Ripard wrote:
> Hi Kishon,
> 
> On Wed, Nov 21, 2018 at 03:59:43PM +0530, Kishon Vijay Abraham I wrote:
>> On 21/11/18 3:41 PM, Maxime Ripard wrote:
>>> Hi Kishon,
>>>
>>> On Tue, Nov 20, 2018 at 11:02:34AM +0530, Kishon Vijay Abraham I wrote:
>>>>>> +static int cdns_dphy_config_from_opts(struct phy *phy,
>>>>>> +				      struct phy_configure_opts_mipi_dphy *opts,
>>>>>> +				      struct cdns_dphy_cfg *cfg)
>>>>>> +{
>>>>>> +	struct cdns_dphy *dphy = phy_get_drvdata(phy);
>>>>>> +	unsigned int dsi_hfp_ext = 0;
>>>>>> +	int ret;
>>>>>> +
>>>>>> +	ret = phy_mipi_dphy_config_validate(opts);
>>>>>> +	if (ret)
>>>>>> +		return ret;
>>>>>> +
>>>>>> +	ret = cdns_dsi_get_dphy_pll_cfg(dphy, cfg,
>>>>>> +					opts, &dsi_hfp_ext);
>>>>>> +	if (ret)
>>>>>> +		return ret;
>>>>>> +
>>>>>> +	opts->wakeup = cdns_dphy_get_wakeup_time_ns(dphy);
>>>>
>>>> Is the wakeup populated here used by the consumer driver?
>>>
>>> It's supposed to, if it can yes.
>>
>> But I guess right now it's not using. I'm thinking the usefulness of validate
>> callback (only from this series point of view). Why should a consumer driver
>> invoke validate if it doesn't intend to configure the PHY?
>>
>> The 3 steps required are
>> 	* The consumer driver gets the default config
>> 	* The consumer driver changes some of the configuration and
>> 	* The consumer driver invokes phy configure callback.
>>
>> phy_configure anyways can validate the config before actually configuring the phy.
> 
> If you only want to configure the PHY, then yes, sure.
> 
> However, the point here is that validate helps negotiating what the
> source device (DSI controller for example) and what the sink device
> (say a panel) are capable of.
> 
> A panel for example might very well have multiple resolutions that it
> supports, and the DSI controller will have some as well. And the PHY
> will only be able to operate within certain boundaries too. However,
> they don't necessarily match, since there's so many panels, and so
> many SoCs.
> 
> Let's say our (very weird) panel is able to do 640x480, 1024x768 and
> 1280x800. Our DSI driver can only operate with 1024 pixels in both
> dimensions, and the PHY can only reach the bus frequency needed for
> around 800x600.
> 
> We'll want to filter out 1280x800 (because the DSI controller can't
> provide that) and 1024x768 (because the PHY can go fast enough), to
> only provide the 640x480 option to the user.
> 
> That's what validate bring you. The option to test whether a given
> configuration *would* work, without actually wanting to apply it right
> now.
> 
> Does that make sense?

Thank you for the explanation. It's clear now.

Thanks
Kishon

Patch

diff --git a/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt b/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt
index f5725bb6c61c..525a4bfd8634 100644
--- a/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt
+++ b/Documentation/devicetree/bindings/display/bridge/cdns,dsi.txt
@@ -31,28 +31,7 @@  Required subnodes:
 - one subnode per DSI device connected on the DSI bus. Each DSI device should
   contain a reg property encoding its virtual channel.
 
-Cadence DPHY
-============
-
-Cadence DPHY block.
-
-Required properties:
-- compatible: should be set to "cdns,dphy".
-- reg: physical base address and length of the DPHY registers.
-- clocks: DPHY reference clocks.
-- clock-names: must contain "psm" and "pll_ref".
-- #phy-cells: must be set to 0.
-
-
 Example:
-	dphy0: dphy@fd0e0000{
-		compatible = "cdns,dphy";
-		reg = <0x0 0xfd0e0000 0x0 0x1000>;
-		clocks = <&psm_clk>, <&pll_ref_clk>;
-		clock-names = "psm", "pll_ref";
-		#phy-cells = <0>;
-	};
-
 	dsi0: dsi@fd0c0000 {
 		compatible = "cdns,dsi";
 		reg = <0x0 0xfd0c0000 0x0 0x1000>;
diff --git a/Documentation/devicetree/bindings/phy/cdns,dphy.txt b/Documentation/devicetree/bindings/phy/cdns,dphy.txt
new file mode 100644
index 000000000000..1095bc4e72d9
--- /dev/null
+++ b/Documentation/devicetree/bindings/phy/cdns,dphy.txt
@@ -0,0 +1,20 @@ 
+Cadence DPHY
+============
+
+Cadence DPHY block.
+
+Required properties:
+- compatible: should be set to "cdns,dphy".
+- reg: physical base address and length of the DPHY registers.
+- clocks: DPHY reference clocks.
+- clock-names: must contain "psm" and "pll_ref".
+- #phy-cells: must be set to 0.
+
+Example:
+	dphy0: dphy@fd0e0000{
+		compatible = "cdns,dphy";
+		reg = <0x0 0xfd0e0000 0x0 0x1000>;
+		clocks = <&psm_clk>, <&pll_ref_clk>;
+		clock-names = "psm", "pll_ref";
+		#phy-cells = <0>;
+	};
diff --git a/drivers/phy/cadence/Kconfig b/drivers/phy/cadence/Kconfig
index 57fff7de4031..240effa81046 100644
--- a/drivers/phy/cadence/Kconfig
+++ b/drivers/phy/cadence/Kconfig
@@ -1,6 +1,7 @@ 
 #
-# Phy driver for Cadence MHDP DisplayPort controller
+# Phy drivers for Cadence IPs
 #
+
 config PHY_CADENCE_DP
 	tristate "Cadence MHDP DisplayPort PHY driver"
 	depends on OF
@@ -8,3 +9,13 @@  config PHY_CADENCE_DP
 	select GENERIC_PHY
 	help
 	  Support for Cadence MHDP DisplayPort PHY.
+
+config PHY_CADENCE_DPHY
+	tristate "Cadence D-PHY Support"
+	depends on HAS_IOMEM && OF
+	select GENERIC_PHY
+	select GENERIC_PHY_MIPI_DPHY
+	help
+	  Choose this option if you have a Cadence D-PHY in your
+	  system. If M is selected, the module will be called
+	  cdns-csi.
diff --git a/drivers/phy/cadence/Makefile b/drivers/phy/cadence/Makefile
index e5b0a11cf28a..64cb9ea66ceb 100644
--- a/drivers/phy/cadence/Makefile
+++ b/drivers/phy/cadence/Makefile
@@ -1 +1,2 @@ 
 obj-$(CONFIG_PHY_CADENCE_DP)	+= phy-cadence-dp.o
+obj-$(CONFIG_PHY_CADENCE_DPHY)	+= cdns-dphy.o
diff --git a/drivers/phy/cadence/cdns-dphy.c b/drivers/phy/cadence/cdns-dphy.c
new file mode 100644
index 000000000000..a398b401e5d3
--- /dev/null
+++ b/drivers/phy/cadence/cdns-dphy.c
@@ -0,0 +1,459 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright: 2017-2018 Cadence Design Systems, Inc.
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+
+#include <linux/phy/phy.h>
+#include <linux/phy/phy-mipi-dphy.h>
+
+#define REG_WAKEUP_TIME_NS		800
+#define DPHY_PLL_RATE_HZ		108000000
+
+/* DPHY registers */
+#define DPHY_PMA_CMN(reg)		(reg)
+#define DPHY_PMA_LCLK(reg)		(0x100 + (reg))
+#define DPHY_PMA_LDATA(lane, reg)	(0x200 + ((lane) * 0x100) + (reg))
+#define DPHY_PMA_RCLK(reg)		(0x600 + (reg))
+#define DPHY_PMA_RDATA(lane, reg)	(0x700 + ((lane) * 0x100) + (reg))
+#define DPHY_PCS(reg)			(0xb00 + (reg))
+
+#define DPHY_CMN_SSM			DPHY_PMA_CMN(0x20)
+#define DPHY_CMN_SSM_EN			BIT(0)
+#define DPHY_CMN_TX_MODE_EN		BIT(9)
+
+#define DPHY_CMN_PWM			DPHY_PMA_CMN(0x40)
+#define DPHY_CMN_PWM_DIV(x)		((x) << 20)
+#define DPHY_CMN_PWM_LOW(x)		((x) << 10)
+#define DPHY_CMN_PWM_HIGH(x)		(x)
+
+#define DPHY_CMN_FBDIV			DPHY_PMA_CMN(0x4c)
+#define DPHY_CMN_FBDIV_VAL(low, high)	(((high) << 11) | ((low) << 22))
+#define DPHY_CMN_FBDIV_FROM_REG		(BIT(10) | BIT(21))
+
+#define DPHY_CMN_OPIPDIV		DPHY_PMA_CMN(0x50)
+#define DPHY_CMN_IPDIV_FROM_REG		BIT(0)
+#define DPHY_CMN_IPDIV(x)		((x) << 1)
+#define DPHY_CMN_OPDIV_FROM_REG		BIT(6)
+#define DPHY_CMN_OPDIV(x)		((x) << 7)
+
+#define DPHY_PSM_CFG			DPHY_PCS(0x4)
+#define DPHY_PSM_CFG_FROM_REG		BIT(0)
+#define DPHY_PSM_CLK_DIV(x)		((x) << 1)
+
+#define DSI_HBP_FRAME_OVERHEAD		12
+#define DSI_HSA_FRAME_OVERHEAD		14
+#define DSI_HFP_FRAME_OVERHEAD		6
+#define DSI_HSS_VSS_VSE_FRAME_OVERHEAD	4
+#define DSI_BLANKING_FRAME_OVERHEAD	6
+#define DSI_NULL_FRAME_OVERHEAD		6
+#define DSI_EOT_PKT_SIZE		4
+
+struct cdns_dphy_cfg {
+	u8 pll_ipdiv;
+	u8 pll_opdiv;
+	u16 pll_fbdiv;
+	unsigned int nlanes;
+};
+
+enum cdns_dphy_clk_lane_cfg {
+	DPHY_CLK_CFG_LEFT_DRIVES_ALL = 0,
+	DPHY_CLK_CFG_LEFT_DRIVES_RIGHT = 1,
+	DPHY_CLK_CFG_LEFT_DRIVES_LEFT = 2,
+	DPHY_CLK_CFG_RIGHT_DRIVES_ALL = 3,
+};
+
+struct cdns_dphy;
+struct cdns_dphy_ops {
+	int (*probe)(struct cdns_dphy *dphy);
+	void (*remove)(struct cdns_dphy *dphy);
+	void (*set_psm_div)(struct cdns_dphy *dphy, u8 div);
+	void (*set_clk_lane_cfg)(struct cdns_dphy *dphy,
+				 enum cdns_dphy_clk_lane_cfg cfg);
+	void (*set_pll_cfg)(struct cdns_dphy *dphy,
+			    const struct cdns_dphy_cfg *cfg);
+	unsigned long (*get_wakeup_time_ns)(struct cdns_dphy *dphy);
+};
+
+struct cdns_dphy {
+	struct cdns_dphy_cfg cfg;
+	void __iomem *regs;
+	struct clk *psm_clk;
+	struct clk *pll_ref_clk;
+	const struct cdns_dphy_ops *ops;
+	struct phy *phy;
+};
+
+static int cdns_dsi_get_dphy_pll_cfg(struct cdns_dphy *dphy,
+				     struct cdns_dphy_cfg *cfg,
+				     struct phy_configure_opts_mipi_dphy *opts,
+				     unsigned int *dsi_hfp_ext)
+{
+	u64 dlane_bps, dlane_bps_max, fbdiv, fbdiv_max, adj_dsi_htotal;
+	unsigned long pll_ref_hz = clk_get_rate(dphy->pll_ref_clk);
+
+	memset(cfg, 0, sizeof(*cfg));
+
+	if (pll_ref_hz < 9600000 || pll_ref_hz >= 150000000)
+		return -EINVAL;
+	else if (pll_ref_hz < 19200000)
+		cfg->pll_ipdiv = 1;
+	else if (pll_ref_hz < 38400000)
+		cfg->pll_ipdiv = 2;
+	else if (pll_ref_hz < 76800000)
+		cfg->pll_ipdiv = 4;
+	else
+		cfg->pll_ipdiv = 8;
+
+	dlane_bps = opts->hs_clk_rate;
+
+	if (dlane_bps > 2500000000UL || dlane_bps < 160000000UL)
+		return -EINVAL;
+	else if (dlane_bps >= 1250000000)
+		cfg->pll_opdiv = 1;
+	else if (dlane_bps >= 630000000)
+		cfg->pll_opdiv = 2;
+	else if (dlane_bps >= 320000000)
+		cfg->pll_opdiv = 4;
+	else if (dlane_bps >= 160000000)
+		cfg->pll_opdiv = 8;
+
+	/*
+	 * Allow a deviation of 0.2% on the per-lane data rate to try to
+	 * recover a potential mismatch between DPI and PPI clks.
+	 */
+	dlane_bps_max = dlane_bps + DIV_ROUND_DOWN_ULL(dlane_bps, 500);
+	fbdiv_max = DIV_ROUND_DOWN_ULL(dlane_bps_max * 2 *
+				       cfg->pll_opdiv * cfg->pll_ipdiv,
+				       pll_ref_hz);
+	fbdiv = DIV_ROUND_UP_ULL(dlane_bps * 2 * cfg->pll_opdiv *
+				 cfg->pll_ipdiv,
+				 pll_ref_hz);
+
+	/*
+	 * Iterate over all acceptable fbdiv and try to find an adjusted DSI
+	 * htotal length providing an exact match.
+	 *
+	 * Note that we could do something even trickier by relying on the fact
+	 * that a new line is not necessarily aligned on a lane boundary, so,
+	 * by making adj_dsi_htotal non aligned on a dsi_lanes we can improve a
+	 * bit the precision. With this, the step would be
+	 *
+	 *	pll_ref_hz / (2 * opdiv * ipdiv * nlanes)
+	 *
+	 * instead of
+	 *
+	 *	pll_ref_hz / (2 * opdiv * ipdiv)
+	 *
+	 * The drawback of this approach is that we would need to make sure the
+	 * number or lines is a multiple of the realignment periodicity which is
+	 * a function of the number of lanes and the original misalignment. For
+	 * example, for NLANES = 4 and HTOTAL % NLANES = 3, it takes 4 lines
+	 * to realign on a lane:
+	 * LINE 0: expected number of bytes, starts emitting first byte of
+	 *	   LINE 1 on LANE 3
+	 * LINE 1: expected number of bytes, starts emitting first 2 bytes of
+	 *	   LINE 2 on LANES 2 and 3
+	 * LINE 2: expected number of bytes, starts emitting first 3 bytes of
+	 *	   of LINE 3 on LANES 1, 2 and 3
+	 * LINE 3: one byte less, now things are realigned on LANE 0 for LINE 4
+	 *
+	 * I figured this extra complexity was not worth the benefit, but if
+	 * someone really has unfixable mismatch, that would be something to
+	 * investigate.
+	 */
+	for (; fbdiv <= fbdiv_max; fbdiv++) {
+		u32 rem;
+
+		/*
+		 * Do the division in 2 steps to avoid an overflow on the
+		 * divider.
+		 */
+		rem = do_div(adj_dsi_htotal, opts->hs_clk_rate);
+		if (rem)
+			continue;
+
+		rem = do_div(adj_dsi_htotal,
+			     cfg->pll_opdiv * cfg->pll_ipdiv * 2 * 8);
+		if (rem)
+			continue;
+
+		cfg->pll_fbdiv = fbdiv;
+		break;
+	}
+
+	/* No match, let's just reject the display mode. */
+	if (!cfg->pll_fbdiv)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int cdns_dphy_setup_psm(struct cdns_dphy *dphy)
+{
+	unsigned long psm_clk_hz = clk_get_rate(dphy->psm_clk);
+	unsigned long psm_div;
+
+	if (!psm_clk_hz || psm_clk_hz > 100000000)
+		return -EINVAL;
+
+	psm_div = DIV_ROUND_CLOSEST(psm_clk_hz, 1000000);
+	if (dphy->ops->set_psm_div)
+		dphy->ops->set_psm_div(dphy, psm_div);
+
+	return 0;
+}
+
+static void cdns_dphy_set_clk_lane_cfg(struct cdns_dphy *dphy,
+				       enum cdns_dphy_clk_lane_cfg cfg)
+{
+	if (dphy->ops->set_clk_lane_cfg)
+		dphy->ops->set_clk_lane_cfg(dphy, cfg);
+}
+
+static void cdns_dphy_set_pll_cfg(struct cdns_dphy *dphy,
+				  const struct cdns_dphy_cfg *cfg)
+{
+	if (dphy->ops->set_pll_cfg)
+		dphy->ops->set_pll_cfg(dphy, cfg);
+}
+
+static unsigned long cdns_dphy_get_wakeup_time_ns(struct cdns_dphy *dphy)
+{
+	return dphy->ops->get_wakeup_time_ns(dphy);
+}
+
+static unsigned long cdns_dphy_ref_get_wakeup_time_ns(struct cdns_dphy *dphy)
+{
+	/* Default wakeup time is 800 ns (in a simulated environment). */
+	return 800;
+}
+
+static void cdns_dphy_ref_set_pll_cfg(struct cdns_dphy *dphy,
+				      const struct cdns_dphy_cfg *cfg)
+{
+	u32 fbdiv_low, fbdiv_high;
+
+	fbdiv_low = (cfg->pll_fbdiv / 4) - 2;
+	fbdiv_high = cfg->pll_fbdiv - fbdiv_low - 2;
+
+	writel(DPHY_CMN_IPDIV_FROM_REG | DPHY_CMN_OPDIV_FROM_REG |
+	       DPHY_CMN_IPDIV(cfg->pll_ipdiv) |
+	       DPHY_CMN_OPDIV(cfg->pll_opdiv),
+	       dphy->regs + DPHY_CMN_OPIPDIV);
+	writel(DPHY_CMN_FBDIV_FROM_REG |
+	       DPHY_CMN_FBDIV_VAL(fbdiv_low, fbdiv_high),
+	       dphy->regs + DPHY_CMN_FBDIV);
+	writel(DPHY_CMN_PWM_HIGH(6) | DPHY_CMN_PWM_LOW(0x101) |
+	       DPHY_CMN_PWM_DIV(0x8),
+	       dphy->regs + DPHY_CMN_PWM);
+}
+
+static void cdns_dphy_ref_set_psm_div(struct cdns_dphy *dphy, u8 div)
+{
+	writel(DPHY_PSM_CFG_FROM_REG | DPHY_PSM_CLK_DIV(div),
+	       dphy->regs + DPHY_PSM_CFG);
+}
+
+/*
+ * This is the reference implementation of DPHY hooks. Specific integration of
+ * this IP may have to re-implement some of them depending on how they decided
+ * to wire things in the SoC.
+ */
+static const struct cdns_dphy_ops ref_dphy_ops = {
+	.get_wakeup_time_ns = cdns_dphy_ref_get_wakeup_time_ns,
+	.set_pll_cfg = cdns_dphy_ref_set_pll_cfg,
+	.set_psm_div = cdns_dphy_ref_set_psm_div,
+};
+
+static int cdns_dphy_config_from_opts(struct phy *phy,
+				      struct phy_configure_opts_mipi_dphy *opts,
+				      struct cdns_dphy_cfg *cfg)
+{
+	struct cdns_dphy *dphy = phy_get_drvdata(phy);
+	unsigned int dsi_hfp_ext = 0;
+	int ret;
+
+	ret = phy_mipi_dphy_config_validate(opts);
+	if (ret)
+		return ret;
+
+	ret = cdns_dsi_get_dphy_pll_cfg(dphy, cfg,
+					opts, &dsi_hfp_ext);
+	if (ret)
+		return ret;
+
+	opts->wakeup = cdns_dphy_get_wakeup_time_ns(dphy);
+
+	return 0;
+}
+
+static int cdns_dphy_init(struct phy *phy)
+{
+	struct cdns_dphy *dphy = phy_get_drvdata(phy);
+
+	clk_prepare_enable(dphy->psm_clk);
+	clk_prepare_enable(dphy->pll_ref_clk);
+
+	return 0;
+}
+
+static int cdns_dphy_validate(struct phy *phy, enum phy_mode mode,
+			      union phy_configure_opts *opts)
+{
+	struct cdns_dphy_cfg cfg = { 0 };
+
+	if (mode != PHY_MODE_MIPI_DPHY)
+		return -EINVAL;
+
+	return cdns_dphy_config_from_opts(phy, &opts->mipi_dphy, &cfg);
+}
+
+static int cdns_dphy_configure(struct phy *phy, union phy_configure_opts *opts)
+{
+	struct cdns_dphy *dphy = phy_get_drvdata(phy);
+	struct cdns_dphy_cfg cfg = { 0 };
+	int ret;
+
+	ret = cdns_dphy_config_from_opts(phy, &opts->mipi_dphy, &cfg);
+	if (ret)
+		return ret;
+
+	/*
+	 * Configure the internal PSM clk divider so that the DPHY has a
+	 * 1MHz clk (or something close).
+	 */
+	ret = cdns_dphy_setup_psm(dphy);
+	if (ret)
+		return ret;
+
+	/*
+	 * Configure attach clk lanes to data lanes: the DPHY has 2 clk lanes
+	 * and 8 data lanes, each clk lane can be attache different set of
+	 * data lanes. The 2 groups are named 'left' and 'right', so here we
+	 * just say that we want the 'left' clk lane to drive the 'left' data
+	 * lanes.
+	 */
+	cdns_dphy_set_clk_lane_cfg(dphy, DPHY_CLK_CFG_LEFT_DRIVES_LEFT);
+
+	/*
+	 * Configure the DPHY PLL that will be used to generate the TX byte
+	 * clk.
+	 */
+	cdns_dphy_set_pll_cfg(dphy, &cfg);
+
+	return 0;
+}
+
+static int cdns_dphy_power_on(struct phy *phy)
+{
+	struct cdns_dphy *dphy = phy_get_drvdata(phy);
+
+	/* Start TX state machine. */
+	writel(DPHY_CMN_SSM_EN | DPHY_CMN_TX_MODE_EN, dphy->regs + DPHY_CMN_SSM);
+
+	return 0;
+}
+
+static int cdns_dphy_exit(struct phy *phy)
+{
+	struct cdns_dphy *dphy = phy_get_drvdata(phy);
+
+	clk_disable_unprepare(dphy->pll_ref_clk);
+	clk_disable_unprepare(dphy->psm_clk);
+
+	return 0;
+}
+
+static struct phy_ops cdns_dphy_ops = {
+	.configure	= cdns_dphy_configure,
+	.validate	= cdns_dphy_validate,
+	.power_on	= cdns_dphy_power_on,
+	.init		= cdns_dphy_init,
+	.exit		= cdns_dphy_exit,
+};
+
+static int cdns_dphy_probe(struct platform_device *pdev)
+{
+	struct phy_provider *phy_provider;
+	struct cdns_dphy *dphy;
+	struct resource *res;
+	int ret;
+
+	dphy = devm_kzalloc(&pdev->dev, sizeof(*dphy), GFP_KERNEL);
+	if (!dphy)
+		return -ENOMEM;
+	dev_set_drvdata(&pdev->dev, dphy);
+
+	dphy->ops = of_device_get_match_data(&pdev->dev);
+	if (!dphy->ops)
+		return -EINVAL;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	dphy->regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(dphy->regs))
+		return PTR_ERR(dphy->regs);
+
+	dphy->psm_clk = devm_clk_get(&pdev->dev, "psm");
+	if (IS_ERR(dphy->psm_clk))
+		return PTR_ERR(dphy->psm_clk);
+
+	dphy->pll_ref_clk = devm_clk_get(&pdev->dev, "pll_ref");
+	if (IS_ERR(dphy->pll_ref_clk))
+		return PTR_ERR(dphy->pll_ref_clk);
+
+	if (dphy->ops->probe) {
+		ret = dphy->ops->probe(dphy);
+		if (ret)
+			return ret;
+	}
+
+	dphy->phy = devm_phy_create(&pdev->dev, NULL, &cdns_dphy_ops);
+	if (IS_ERR(dphy->phy)) {
+		dev_err(&pdev->dev, "failed to create PHY\n");
+		return PTR_ERR(dphy->phy);
+	}
+
+	phy_set_drvdata(dphy->phy, dphy);
+	phy_provider = devm_of_phy_provider_register(&pdev->dev, of_phy_simple_xlate);
+
+	return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static int cdns_dphy_remove(struct platform_device *pdev)
+{
+	struct cdns_dphy *dphy = dev_get_drvdata(&pdev->dev);
+
+	if (dphy->ops->remove)
+		dphy->ops->remove(dphy);
+
+	return 0;
+}
+
+static const struct of_device_id cdns_dphy_of_match[] = {
+	{ .compatible = "cdns,dphy", .data = &ref_dphy_ops },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, cdns_dphy_of_match);
+
+static struct platform_driver cdns_dphy_platform_driver = {
+	.probe		= cdns_dphy_probe,
+	.remove		= cdns_dphy_remove,
+	.driver		= {
+		.name		= "cdns-mipi-dphy",
+		.of_match_table	= cdns_dphy_of_match,
+	},
+};
+module_platform_driver(cdns_dphy_platform_driver);
+
+MODULE_AUTHOR("Maxime Ripard <maxime.ripard@bootlin>");
+MODULE_DESCRIPTION("Cadence MIPI D-PHY Driver");
+MODULE_LICENSE("GPL");

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