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SubjectRe: [PATCH] drm/panel: simple: Support reset GPIOs
Hi Miquel.

On Fri, Dec 13, 2019 at 07:13:25PM +0100, Miquel Raynal wrote:
> The panel common bindings provide a gpios-reset property which is
> active low by default. Let's support it in the simple driver.
>
> De-asserting the reset pin implies a physical high, which in turns is
> a logic low.
>
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

Code looks fine - but I fail to see why simple panels would require a
reset pin.

Do you have any simple panels that requires this, or did you add it
because you saw it in the panel-common.yaml file?

Sam


> ---
> drivers/gpu/drm/panel/panel-simple.c | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
> index 5d487686d25c..15dd495c347d 100644
> --- a/drivers/gpu/drm/panel/panel-simple.c
> +++ b/drivers/gpu/drm/panel/panel-simple.c
> @@ -110,6 +110,7 @@ struct panel_simple {
> struct i2c_adapter *ddc;
>
> struct gpio_desc *enable_gpio;
> + struct gpio_desc *reset_gpio;
>
> struct drm_display_mode override_mode;
> };
> @@ -433,12 +434,21 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)
> if (IS_ERR(panel->supply))
> return PTR_ERR(panel->supply);
>
> + panel->reset_gpio = devm_gpiod_get_optional(dev, "reset",
> + GPIOD_OUT_LOW);
> + if (IS_ERR(panel->reset_gpio)) {
> + err = PTR_ERR(panel->reset_gpio);
> + if (err != -EPROBE_DEFER)
> + dev_err(dev, "failed to request reset pin: %d\n", err);
> + return err;
> + }
> +
> panel->enable_gpio = devm_gpiod_get_optional(dev, "enable",
> GPIOD_OUT_LOW);
> if (IS_ERR(panel->enable_gpio)) {
> err = PTR_ERR(panel->enable_gpio);
> if (err != -EPROBE_DEFER)
> - dev_err(dev, "failed to request GPIO: %d\n", err);
> + dev_err(dev, "failed to request enable pin: %d\n", err);
> return err;
> }
>
> --
> 2.20.1

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