Re: [21/21] drm/bridge: tc358767: implement naive HPD handling

[Andrey Smirnov <andrew.smirnov@gmail.com>]

On Tue, Mar 19, 2019 at 11:18 AM Andrey Smirnov
<andrew.smirnov@gmail.com> wrote:
>
> > tc358767 driver doesn't have any HPD handling at the moment, as it was
> > originally developed to support only eDP.
>
> > This patch implements a naive, polling-based HPD handling, which is used
> > when the driver is in DP mode.
>
> > Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> > ---
> >  drivers/gpu/drm/bridge/tc358767.c | 56 +++++++++++++++++++++----------
> >  1 file changed, 38 insertions(+), 18 deletions(-)
>
> > diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
> > index 8606de29c9b2..2b252f7ac070 100644
> > --- a/drivers/gpu/drm/bridge/tc358767.c
> > +++ b/drivers/gpu/drm/bridge/tc358767.c
> > @@ -1095,6 +1095,12 @@ static void tc_bridge_enable(struct drm_bridge *bridge)
> >       struct tc_data *tc = bridge_to_tc(bridge);
> >       int ret;
>
> > +     ret = tc_get_display_props(tc);
> > +     if (ret < 0) {
> > +             dev_err(tc->dev, "failed to read display props: %d\n", ret);
> > +             return;
> > +     }
> > +
> >       ret = tc_main_link_enable(tc);
> >       if (ret < 0) {
> >               dev_err(tc->dev, "main link enable error: %d\n", ret);
> > @@ -1200,19 +1206,35 @@ static int tc_connector_get_modes(struct drm_connector *connector)
> >       return count;
> >  }
>
> > -static void tc_connector_set_polling(struct tc_data *tc,
> > -                                  struct drm_connector *connector)
> > -{
> > -     /* TODO: add support for HPD */
> > -     connector->polled = DRM_CONNECTOR_POLL_CONNECT |
> > -                         DRM_CONNECTOR_POLL_DISCONNECT;
> > -}
> > -
> >  static const struct drm_connector_helper_funcs tc_connector_helper_funcs = {
> >       .get_modes = tc_connector_get_modes,
> >  };
>
> > +static enum drm_connector_status tc_connector_detect(struct drm_connector *connector, bool force)
> > +{
> > +     struct tc_data *tc = connector_to_tc(connector);
> > +     u32 val;
> > +     int ret;
> > +     bool conn;
> > +
> > +     tc_read(GPIOI, &val);
> > +
> > +     conn = val & BIT(0);

Another thing I noticed when trying this patch is that
tc_connector_detect() will get called via drm_helper_probe_detect()
even if tc->panel is not NULL and tc->connector.polled is zero, which
creates a problem for eDP use-case.

Thanks,
Andrey Smirnov
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