Re: [PATCH v2 09/50] drm/bridge: simple-bridge: Add support for enable GPIO

[Boris Brezillon <boris.brezillon@collabora.com>]

On Tue, 20 Aug 2019 04:16:40 +0300
Laurent Pinchart <laurent.pinchart@ideasonboard.com> wrote:

> If an enable GPIO is declared in the firmware, assert it when enabling
> the bridge and deassert it when disabling it.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
> Reviewed-by: Stefan Agner <stefan@agner.ch>

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>

> ---
>  drivers/gpu/drm/bridge/simple-bridge.c | 22 ++++++++++++++++++----
>  1 file changed, 18 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/simple-bridge.c b/drivers/gpu/drm/bridge/simple-bridge.c
> index 85aa852eafb4..3e5031833368 100644
> --- a/drivers/gpu/drm/bridge/simple-bridge.c
> +++ b/drivers/gpu/drm/bridge/simple-bridge.c
> @@ -6,6 +6,7 @@
>   * Maxime Ripard <maxime.ripard@free-electrons.com>
>   */
>  
> +#include <linux/gpio/consumer.h>
>  #include <linux/module.h>
>  #include <linux/of_device.h>
>  #include <linux/of_graph.h>
> @@ -29,6 +30,7 @@ struct simple_bridge {
>  
>  	struct i2c_adapter	*ddc;
>  	struct regulator	*vdd;
> +	struct gpio_desc	*enable;
>  };
>  
>  static inline struct simple_bridge *
> @@ -140,19 +142,23 @@ static int simple_bridge_attach(struct drm_bridge *bridge,
>  static void simple_bridge_enable(struct drm_bridge *bridge)
>  {
>  	struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge);
> -	int ret = 0;
> +	int ret;
>  
> -	if (sbridge->vdd)
> +	if (sbridge->vdd) {
>  		ret = regulator_enable(sbridge->vdd);
> +		if (ret)
> +			DRM_ERROR("Failed to enable vdd regulator: %d\n", ret);
> +	}
>  
> -	if (ret)
> -		DRM_ERROR("Failed to enable vdd regulator: %d\n", ret);
> +	gpiod_set_value_cansleep(sbridge->enable, 1);
>  }
>  
>  static void simple_bridge_disable(struct drm_bridge *bridge)
>  {
>  	struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge);
>  
> +	gpiod_set_value_cansleep(sbridge->enable, 0);
> +
>  	if (sbridge->vdd)
>  		regulator_disable(sbridge->vdd);
>  }
> @@ -205,6 +211,14 @@ static int simple_bridge_probe(struct platform_device *pdev)
>  		dev_dbg(&pdev->dev, "No vdd regulator found: %d\n", ret);
>  	}
>  
> +	sbridge->enable = devm_gpiod_get_optional(&pdev->dev, "enable",
> +						  GPIOD_OUT_LOW);
> +	if (IS_ERR(sbridge->enable)) {
> +		if (PTR_ERR(sbridge->enable) != -EPROBE_DEFER)
> +			dev_err(&pdev->dev, "Unable to retrieve enable GPIO\n");
> +		return PTR_ERR(sbridge->enable);
> +	}
> +
>  	sbridge->ddc = simple_bridge_retrieve_ddc(&pdev->dev);
>  	if (IS_ERR(sbridge->ddc)) {
>  		if (PTR_ERR(sbridge->ddc) == -ENODEV) {

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