Hi Peter,
Am Freitag, 7. Januar 2022, 06:13:33 CET schrieb Peter Geis:
> Some implementations do not use the reset signal, instead tying it to dvdd.
> Make the reset gpio optional to permit this.
>
> Signed-off-by: Peter Geis <pgwipeout@xxxxxxxxx>
> ---
> drivers/gpu/drm/panel/panel-feiyang-fy07024di26a30d.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/panel/panel-feiyang-fy07024di26a30d.c b/drivers/gpu/drm/panel/panel-feiyang-fy07024di26a30d.c
> index 581661b506f8..1c88d752b14e 100644
> --- a/drivers/gpu/drm/panel/panel-feiyang-fy07024di26a30d.c
> +++ b/drivers/gpu/drm/panel/panel-feiyang-fy07024di26a30d.c
> @@ -65,7 +65,8 @@ static int feiyang_prepare(struct drm_panel *panel)
> /* T3 (dvdd rise + avdd start + avdd rise) T3 >= 20ms */
> msleep(20);
>
> - gpiod_set_value(ctx->reset, 0);
> + if (ctx->reset)
> + gpiod_set_value(ctx->reset, 0);
gpio_set_value does
VALIDATE_DESC_VOID(desc);
which checks for "desc" (ctx->reset in this case) to be valid and especially
not null and simply returns when this is the case.
So from what I see, we don't need all the added conditionals here and below
and would just need the switch to devm_gpiod_get_optional alone.
Heiko
>
> /*
> * T5 + T6 (avdd rise + video & logic signal rise)
> @@ -73,7 +74,8 @@ static int feiyang_prepare(struct drm_panel *panel)
> */
> msleep(20);
>
> - gpiod_set_value(ctx->reset, 1);
> + if (ctx->reset)
> + gpiod_set_value(ctx->reset, 1);
>
> /* T12 (video & logic signal rise + backlight rise) T12 >= 200ms */
> msleep(200);
> @@ -126,7 +128,8 @@ static int feiyang_unprepare(struct drm_panel *panel)
> /* T13 (backlight fall + video & logic signal fall) T13 >= 200ms */
> msleep(200);
>
> - gpiod_set_value(ctx->reset, 0);
> + if (ctx->reset)
> + gpiod_set_value(ctx->reset, 0);
>
> regulator_disable(ctx->avdd);
>
> @@ -211,7 +214,7 @@ static int feiyang_dsi_probe(struct mipi_dsi_device *dsi)
> return PTR_ERR(ctx->avdd);
> }
>
> - ctx->reset = devm_gpiod_get(&dsi->dev, "reset", GPIOD_OUT_LOW);
> + ctx->reset = devm_gpiod_get_optional(&dsi->dev, "reset", GPIOD_OUT_LOW);
> if (IS_ERR(ctx->reset)) {
> dev_err(&dsi->dev, "Couldn't get our reset GPIO\n");
> return PTR_ERR(ctx->reset);
>
