On Sun, Nov 6, 2016 at 7:09 PM, Icenowy Zheng <icenowy@xxxxxxxx> wrote:
> The enable gpio of simple-panel may be used by a simplefb or other
> driver on the panel's display before the KMS driver get load.
>
> Get the GPIO as-is, so the panel won't be disabled, and the simplefb
> can work.
>
> Signed-off-by: Icenowy Zheng <icenowy@xxxxxxxx>
> ---
> drivers/gpu/drm/panel/panel-simple.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
> index 113db3c..ccee4c1 100644
> --- a/drivers/gpu/drm/panel/panel-simple.c
> +++ b/drivers/gpu/drm/panel/panel-simple.c
> @@ -312,7 +312,7 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)
> return PTR_ERR(panel->supply);
>
> panel->enable_gpio = devm_gpiod_get_optional(dev, "enable",
> - GPIOD_OUT_LOW);
> + GPIOD_ASIS);
The GPIO requested as-is might be in input mode. You should change the
gpiod_set_value calls to gpiod_direction_output calls. The later also
allows you to give an initial value. Not sure if it checks for cansleep
like the set_value calls though.
Regards
ChenYu
> if (IS_ERR(panel->enable_gpio)) {
> err = PTR_ERR(panel->enable_gpio);
> dev_err(dev, "failed to request GPIO: %d\n", err);
> --
> 2.10.1
>
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