Hi,
On Sat, Feb 11, 2023 at 06:17:48PM +0100, Frank Oltmanns wrote:
> From: Ondrej Jirman <megi@xxxxxx>
>
> Switching to a different reset sequence, enabling IOVCC before enabling
> VCC.
>
> There also needs to be a delay after enabling the supplies and before
> deasserting the reset. The datasheet specifies 1ms after the supplies
> reach the required voltage. Use 10-20ms to also give the power supplies
> some time to reach the required voltage, too.
>
> This fixes intermittent panel initialization failures and screen
> corruption during resume from sleep on panel xingbangda,xbd599 (e.g.
> used in PinePhone).
>
> Signed-off-by: Ondrej Jirman <megi@xxxxxx>
> Signed-off-by: Frank Oltmanns <frank@xxxxxxxxxxxx>
> Reported-by: Samuel Holland <samuel@xxxxxxxxxxxx>
> ---
> drivers/gpu/drm/panel/panel-sitronix-st7703.c | 25 ++++++++++---------
> 1 file changed, 13 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/panel/panel-sitronix-st7703.c b/drivers/gpu/drm/panel/panel-sitronix-st7703.c
> index 6747ca237ced..45695aa51f62 100644
> --- a/drivers/gpu/drm/panel/panel-sitronix-st7703.c
> +++ b/drivers/gpu/drm/panel/panel-sitronix-st7703.c
> @@ -411,29 +411,30 @@ static int st7703_prepare(struct drm_panel *panel)
> return 0;
>
> dev_dbg(ctx->dev, "Resetting the panel\n");
> - ret = regulator_enable(ctx->vcc);
> + gpiod_set_value_cansleep(ctx->reset_gpio, 1);
> +
> + ret = regulator_enable(ctx->iovcc);
> if (ret < 0) {
> - dev_err(ctx->dev, "Failed to enable vcc supply: %d\n", ret);
> + dev_err(ctx->dev, "Failed to enable iovcc supply: %d\n", ret);
> return ret;
> }
> - ret = regulator_enable(ctx->iovcc);
> +
> + ret = regulator_enable(ctx->vcc);
> if (ret < 0) {
> - dev_err(ctx->dev, "Failed to enable iovcc supply: %d\n", ret);
> - goto disable_vcc;
> + dev_err(ctx->dev, "Failed to enable vcc supply: %d\n", ret);
> + regulator_disable(ctx->iovcc);
> + return ret;
> }
>
> - gpiod_set_value_cansleep(ctx->reset_gpio, 1);
> - usleep_range(20, 40);
> + /* Give power supplies time to stabilize before deasserting reset. */
> + usleep_range(10000, 20000);
> +
> gpiod_set_value_cansleep(ctx->reset_gpio, 0);
> - msleep(20);
> + usleep_range(15000, 20000);
>
> ctx->prepared = true;
>
> return 0;
> -
> -disable_vcc:
> - regulator_disable(ctx->vcc);
> - return ret;
> }
>
> static const u32 mantix_bus_formats[] = {
Reviewed-by: Guido Günther <agx@xxxxxxxxxxx>
Cheers,
-- Guido
> --
> 2.39.1
>
