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SubjectRe: [PATCH v3 5/5] drm/bridge: lvds-encoder: add powerdown-gpios support
Hi Peter,

Thank you for the patch.

On Sat, Dec 29, 2018 at 07:07:43AM +0000, Peter Rosin wrote:
> Optionally power down the LVDS-encoder when it is not in use.
>
> Signed-off-by: Peter Rosin <peda@axentia.se>

As the powerdown-gpios property is only defined for two encoders, and
both of them should work well with this code, I think the change is
fine. In the future if different power-up/down sequences need to be
implemented for different devices this will need to be made
device-specific.

> ---
> drivers/gpu/drm/bridge/lvds-encoder.c | 34 ++++++++++++++++++++++++++++++++++
> 1 file changed, 34 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/lvds-encoder.c b/drivers/gpu/drm/bridge/lvds-encoder.c
> index f6770e83d49d..36d8557bc097 100644
> --- a/drivers/gpu/drm/bridge/lvds-encoder.c
> +++ b/drivers/gpu/drm/bridge/lvds-encoder.c
> @@ -11,11 +11,13 @@
> #include <drm/drm_bridge.h>
> #include <drm/drm_panel.h>
>
> +#include <linux/gpio/consumer.h>
> #include <linux/of_graph.h>
>
> struct lvds_encoder {
> struct drm_bridge bridge;
> struct drm_bridge *panel_bridge;
> + struct gpio_desc *powerdown_gpio;
> };
>
> static int lvds_encoder_attach(struct drm_bridge *bridge)
> @@ -28,8 +30,30 @@ static int lvds_encoder_attach(struct drm_bridge *bridge)
> bridge);
> }
>
> +static void lvds_encoder_enable(struct drm_bridge *bridge)
> +{
> + struct lvds_encoder *lvds_encoder = container_of(bridge,
> + struct lvds_encoder,
> + bridge);
> +
> + if (lvds_encoder->powerdown_gpio)
> + gpiod_set_value_cansleep(lvds_encoder->powerdown_gpio, 0);

gpiod_set_value_cansleep() already contains a NULL check, so you can
drop it from here.

> +}
> +
> +static void lvds_encoder_disable(struct drm_bridge *bridge)
> +{
> + struct lvds_encoder *lvds_encoder = container_of(bridge,
> + struct lvds_encoder,
> + bridge);
> +
> + if (lvds_encoder->powerdown_gpio)
> + gpiod_set_value_cansleep(lvds_encoder->powerdown_gpio, 1);

Same here.

> +}
> +
> static struct drm_bridge_funcs funcs = {

While at it, could you make this const ?

With these fixed,

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

> .attach = lvds_encoder_attach,
> + .enable = lvds_encoder_enable,
> + .disable = lvds_encoder_disable,
> };
> static int lvds_encoder_probe(struct platform_device *pdev)
> @@ -45,6 +69,16 @@ static int lvds_encoder_probe(struct platform_device *pdev)
> if (!lvds_encoder)
> return -ENOMEM;
>
> + lvds_encoder->powerdown_gpio = devm_gpiod_get_optional(dev, "powerdown",
> + GPIOD_OUT_HIGH);
> + if (IS_ERR(lvds_encoder->powerdown_gpio)) {
> + int err = PTR_ERR(lvds_encoder->powerdown_gpio);
> +
> + if (err != -EPROBE_DEFER)
> + dev_err(dev, "powerdown GPIO failure: %d\n", err);
> + return err;
> + }
> +
> /* Locate the panel DT node. */
> port = of_graph_get_port_by_id(dev->of_node, 1);
> if (!port) {

--
Regards,

Laurent Pinchart

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