[PATCH v4 4/4] drm/bridge: ti-sn65dsi83: Add vcc supply regulator support

[Laurent Pinchart]

Hi Alexander,

Thank you for the patch.

On Thu, Nov 18, 2021 at 10:19:55AM +0100, Alexander Stein wrote:
> VCC needs to be enabled before releasing the enable GPIO.
> 
> Signed-off-by: Alexander Stein <alexander.stein at ew.tq-group.com>
> ---
>  drivers/gpu/drm/bridge/ti-sn65dsi83.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi83.c b/drivers/gpu/drm/bridge/ti-sn65dsi83.c
> index 065610edc37a..54d18e82ed74 100644
> --- a/drivers/gpu/drm/bridge/ti-sn65dsi83.c
> +++ b/drivers/gpu/drm/bridge/ti-sn65dsi83.c
> @@ -33,6 +33,7 @@
>  #include <linux/of_device.h>
>  #include <linux/of_graph.h>
>  #include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
>  
>  #include <drm/drm_atomic_helper.h>
>  #include <drm/drm_bridge.h>
> @@ -143,6 +144,7 @@ struct sn65dsi83 {
>  	struct mipi_dsi_device		*dsi;
>  	struct drm_bridge		*panel_bridge;
>  	struct gpio_desc		*enable_gpio;
> +	struct regulator		*vcc;
>  	int				dsi_lanes;
>  	bool				lvds_dual_link;
>  	bool				lvds_dual_link_even_odd_swap;
> @@ -337,6 +339,12 @@ static void sn65dsi83_atomic_enable(struct drm_bridge *bridge,
>  	u16 val;
>  	int ret;
>  
> +	ret = regulator_enable(ctx->vcc);
> +	if (ret) {
> +		dev_err(ctx->dev, "Failed to enable vcc\n");

I'd print the error code here as you do so in
sn65dsi83_atomic_disable().

> +		return;
> +	}
> +
>  	/* Deassert reset */
>  	gpiod_set_value(ctx->enable_gpio, 1);
>  	usleep_range(1000, 1100);
> @@ -486,11 +494,16 @@ static void sn65dsi83_atomic_disable(struct drm_bridge *bridge,
>  				     struct drm_bridge_state *old_bridge_state)
>  {
>  	struct sn65dsi83 *ctx = bridge_to_sn65dsi83(bridge);
> +	int ret;
>  
>  	/* Put the chip in reset, pull EN line low, and assure 10ms reset low timing. */
>  	gpiod_set_value(ctx->enable_gpio, 0);
>  	usleep_range(10000, 11000);
>  
> +	ret = regulator_disable(ctx->vcc);
> +	if (ret)
> +		dev_err(ctx->dev, "Failed to disable vcc: %i\n", ret);

I wish printf didn't have identical %i and %d specifiers :-)

> +
>  	regcache_mark_dirty(ctx->regmap);
>  }
>  
> @@ -599,6 +612,12 @@ static int sn65dsi83_parse_dt(struct sn65dsi83 *ctx, enum sn65dsi83_model model)
>  
>  	ctx->panel_bridge = panel_bridge;
>  
> +	ctx->vcc = devm_regulator_get(dev, "vcc");
> +	if (IS_ERR(ctx->vcc))
> +		return dev_err_probe(dev, PTR_ERR(ctx->vcc),
> +				     "Failed to get supply 'vcc': %pe\n",
> +				     ERR_PTR(ret));

This doesn't seem right, ret doesn't contain any useful error code at
this point.

		return dev_err_probe(dev, PTR_ERR(ctx->vcc),
				     "Failed to get supply 'vcc'\n");

should be enough, as dev_err_probe() adds the error to the message
internally.

With those small fixes,

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

> +
>  	return 0;
>  }
>  

-- 
Regards,

Laurent Pinchart