Re: [PATCH v4 4/4] drm/bridge: ti-sn65dsi83: Add vcc supply regulator support

[Jagan Teki <jagan@amarulasolutions.com>]

Hi Laurent,

On Thu, Dec 9, 2021 at 10:09 PM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Jagan,
>
> On Thu, Dec 09, 2021 at 12:34:49PM +0530, Jagan Teki wrote:
> > On Thu, Nov 18, 2021 at 2:50 PM Alexander Stein wrote:
> > >
> > > VCC needs to be enabled before releasing the enable GPIO.
> > >
> > > Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
> > > ---
> > >  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");
> > > +               return;
> > > +       }
> >
> > Better check the vcc and enable it since it is an optional one.
>
> Won't the regulator core create a dummy regulator if none is specified
> in DT ?

Agreed, thanks (Usually I do check to avoid NULL pointer if any).

Jagan.