[v3,09/12] media: i2c: max9286: Configure remote I2C speed from device tree

  Read the maxim,i2c-clock-frequency DT property that specifies the speed
of the remote I2C bus, and configure the MAX9286 accordingly. The remote
serializers must all have a matching configuration.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
---
Changes since v2:

- Rename DT property to "maxim,i2c-remote-bus-hz"
---
 drivers/media/i2c/max9286.c | 56 +++++++++++++++++++++++++++++++------
 1 file changed, 47 insertions(+), 9 deletions(-)
  

Hi Laurent

On Thu, Dec 15, 2022 at 01:38:22AM +0200, Laurent Pinchart wrote:
> Read the maxim,i2c-clock-frequency DT property that specifies the speed
> of the remote I2C bus, and configure the MAX9286 accordingly. The remote
> serializers must all have a matching configuration.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> ---
> Changes since v2:
>
> - Rename DT property to "maxim,i2c-remote-bus-hz"
> ---
>  drivers/media/i2c/max9286.c | 56 +++++++++++++++++++++++++++++++------
>  1 file changed, 47 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
> index e78456c8d24c..fffb0d2da416 100644
> --- a/drivers/media/i2c/max9286.c
> +++ b/drivers/media/i2c/max9286.c
> @@ -144,6 +144,11 @@ struct max9286_format_info {
>  	u8 datatype;
>  };
>
> +struct max9286_i2c_speed {
> +	u32 rate;
> +	u8 mstbt;
> +};
> +
>  struct max9286_source {
>  	struct v4l2_subdev *sd;
>  	struct fwnode_handle *fwnode;
> @@ -177,6 +182,7 @@ struct max9286_priv {
>  	/* The initial reverse control channel amplitude. */
>  	u32 init_rev_chan_mv;
>  	u32 rev_chan_mv;
> +	u8 i2c_mstbt;
>
>  	bool use_gpio_poc;
>  	u32 gpio_poc[2];
> @@ -254,6 +260,17 @@ static const struct max9286_format_info max9286_formats[] = {
>  	},
>  };
>
> +static const struct max9286_i2c_speed max9286_i2c_speeds[] = {
> +	{ .rate =   8470, .mstbt = MAX9286_I2CMSTBT_8KBPS },
> +	{ .rate =  28300, .mstbt = MAX9286_I2CMSTBT_28KBPS },
> +	{ .rate =  84700, .mstbt = MAX9286_I2CMSTBT_84KBPS },
> +	{ .rate = 105000, .mstbt = MAX9286_I2CMSTBT_105KBPS },
> +	{ .rate = 173000, .mstbt = MAX9286_I2CMSTBT_173KBPS },
> +	{ .rate = 339000, .mstbt = MAX9286_I2CMSTBT_339KBPS },
> +	{ .rate = 533000, .mstbt = MAX9286_I2CMSTBT_533KBPS },
> +	{ .rate = 837000, .mstbt = MAX9286_I2CMSTBT_837KBPS },
> +};
> +
>  /* -----------------------------------------------------------------------------
>   * I2C IO
>   */
> @@ -374,7 +391,7 @@ static int max9286_i2c_mux_init(struct max9286_priv *priv)
>  static void max9286_configure_i2c(struct max9286_priv *priv, bool localack)
>  {
>  	u8 config = MAX9286_I2CSLVSH_469NS_234NS | MAX9286_I2CSLVTO_1024US |
> -		    MAX9286_I2CMSTBT_105KBPS;
> +		    priv->i2c_mstbt;
>
>  	if (localack)
>  		config |= MAX9286_I2CLOCACK;
> @@ -1387,6 +1404,8 @@ static int max9286_parse_dt(struct max9286_priv *priv)
>  	struct device_node *node = NULL;
>  	unsigned int i2c_mux_mask = 0;
>  	u32 reverse_channel_microvolt;
> +	u32 i2c_clk_freq = 105000;
> +	unsigned int i;
>
>  	/* Balance the of_node_put() performed by of_find_node_by_name(). */
>  	of_node_get(dev->of_node);
> @@ -1477,6 +1496,23 @@ static int max9286_parse_dt(struct max9286_priv *priv)
>  	}
>  	of_node_put(node);
>
> +	of_property_read_u32(dev->of_node, "maxim,i2c-remote-bus-hz",
> +			     &i2c_clk_freq);

i2c_clk_freq is only overwritten if the property is present, so I
guess this is right.

Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>

> +	for (i = 0; i < ARRAY_SIZE(max9286_i2c_speeds); ++i) {
> +		const struct max9286_i2c_speed *speed = &max9286_i2c_speeds[i];
> +
> +		if (speed->rate == i2c_clk_freq) {
> +			priv->i2c_mstbt = speed->mstbt;
> +			break;
> +		}
> +	}
> +
> +	if (i == ARRAY_SIZE(max9286_i2c_speeds)) {
> +		dev_err(dev, "Invalid %s value %u\n", "maxim,i2c-remote-bus-hz",
> +			i2c_clk_freq);
> +		return -EINVAL;
> +	}
> +
>  	/*
>  	 * Parse the initial value of the reverse channel amplitude from
>  	 * the firmware interface and convert it to millivolts.
> @@ -1553,10 +1589,16 @@ static int max9286_probe(struct i2c_client *client)
>  	/* GPIO values default to high */
>  	priv->gpio_state = BIT(0) | BIT(1);
>
> +	ret = max9286_parse_dt(priv);
> +	if (ret)
> +		goto err_cleanup_dt;
> +
>  	priv->gpiod_pwdn = devm_gpiod_get_optional(&client->dev, "enable",
>  						   GPIOD_OUT_HIGH);
> -	if (IS_ERR(priv->gpiod_pwdn))
> -		return PTR_ERR(priv->gpiod_pwdn);
> +	if (IS_ERR(priv->gpiod_pwdn)) {
> +		ret = PTR_ERR(priv->gpiod_pwdn);
> +		goto err_cleanup_dt;
> +	}
>
>  	gpiod_set_consumer_name(priv->gpiod_pwdn, "max9286-pwdn");
>  	gpiod_set_value_cansleep(priv->gpiod_pwdn, 1);
> @@ -1583,10 +1625,6 @@ static int max9286_probe(struct i2c_client *client)
>  	if (ret)
>  		goto err_powerdown;
>
> -	ret = max9286_parse_dt(priv);
> -	if (ret)
> -		goto err_cleanup_dt;
> -
>  	if (!priv->use_gpio_poc) {
>  		ret = max9286_get_poc_supplies(priv);
>  		if (ret)
> @@ -1599,10 +1637,10 @@ static int max9286_probe(struct i2c_client *client)
>
>  	return 0;
>
> -err_cleanup_dt:
> -	max9286_cleanup_dt(priv);
>  err_powerdown:
>  	gpiod_set_value_cansleep(priv->gpiod_pwdn, 0);
> +err_cleanup_dt:
> +	max9286_cleanup_dt(priv);
>
>  	return ret;
>  }
> --
> Regards,
>
> Laurent Pinchart
>