From: Ondrej Jirman megi@xff.cz
[ Upstream commit d12d635bb03c7cb4830acb641eb176ee9ff2aa89 ]
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@xff.cz Signed-off-by: Frank Oltmanns frank@oltmanns.dev Reported-by: Samuel Holland samuel@sholland.org Reviewed-by: Guido Günther agx@sigxcpu.org Tested-by: Guido Günther agx@sigxcpu.org Signed-off-by: Guido Günther agx@sigxcpu.org Link: https://patchwork.freedesktop.org/patch/msgid/20230211171748.36692-2-frank@o... Signed-off-by: Sasha Levin sashal@kernel.org --- 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 a2c303e5732c0..f50cc70e6337c 100644 --- a/drivers/gpu/drm/panel/panel-sitronix-st7703.c +++ b/drivers/gpu/drm/panel/panel-sitronix-st7703.c @@ -428,29 +428,30 @@ 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 int st7703_get_modes(struct drm_panel *panel,