Hi Alexander, Thank you for the patch. On Thu, Nov 18, 2021 at 10:19:55AM +0100, Alexander Stein wrote: > VCC needs to be enabled before releasing the enable GPIO. > > Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx> > --- > drivers/gpu/drm/bridge/ti-sn65dsi83.c | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi83.c b/drivers/gpu/drm/bridge/ti-sn65dsi83.c > index 065610edc37a..54d18e82ed74 100644 > --- a/drivers/gpu/drm/bridge/ti-sn65dsi83.c > +++ b/drivers/gpu/drm/bridge/ti-sn65dsi83.c > @@ -33,6 +33,7 @@ > #include <linux/of_device.h> > #include <linux/of_graph.h> > #include <linux/regmap.h> > +#include <linux/regulator/consumer.h> > > #include <drm/drm_atomic_helper.h> > #include <drm/drm_bridge.h> > @@ -143,6 +144,7 @@ struct sn65dsi83 { > struct mipi_dsi_device *dsi; > struct drm_bridge *panel_bridge; > struct gpio_desc *enable_gpio; > + struct regulator *vcc; > int dsi_lanes; > bool lvds_dual_link; > bool lvds_dual_link_even_odd_swap; > @@ -337,6 +339,12 @@ static void sn65dsi83_atomic_enable(struct drm_bridge *bridge, > u16 val; > int ret; > > + ret = regulator_enable(ctx->vcc); > + if (ret) { > + dev_err(ctx->dev, "Failed to enable vcc\n"); I'd print the error code here as you do so in sn65dsi83_atomic_disable(). > + return; > + } > + > /* Deassert reset */ > gpiod_set_value(ctx->enable_gpio, 1); > usleep_range(1000, 1100); > @@ -486,11 +494,16 @@ static void sn65dsi83_atomic_disable(struct drm_bridge *bridge, > struct drm_bridge_state *old_bridge_state) > { > struct sn65dsi83 *ctx = bridge_to_sn65dsi83(bridge); > + int ret; > > /* Put the chip in reset, pull EN line low, and assure 10ms reset low timing. */ > gpiod_set_value(ctx->enable_gpio, 0); > usleep_range(10000, 11000); > > + ret = regulator_disable(ctx->vcc); > + if (ret) > + dev_err(ctx->dev, "Failed to disable vcc: %i\n", ret); I wish printf didn't have identical %i and %d specifiers :-) > + > regcache_mark_dirty(ctx->regmap); > } > > @@ -599,6 +612,12 @@ static int sn65dsi83_parse_dt(struct sn65dsi83 *ctx, enum sn65dsi83_model model) > > ctx->panel_bridge = panel_bridge; > > + ctx->vcc = devm_regulator_get(dev, "vcc"); > + if (IS_ERR(ctx->vcc)) > + return dev_err_probe(dev, PTR_ERR(ctx->vcc), > + "Failed to get supply 'vcc': %pe\n", > + ERR_PTR(ret)); This doesn't seem right, ret doesn't contain any useful error code at this point. return dev_err_probe(dev, PTR_ERR(ctx->vcc), "Failed to get supply 'vcc'\n"); should be enough, as dev_err_probe() adds the error to the message internally. With those small fixes, Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > + > return 0; > } > -- Regards, Laurent Pinchart