Re: [PATCH v3 2/9] drm/sun4i: tcon: Add TCON LCD support for R40

[Maxime Ripard]

On Thu, Jan 02, 2020 at 09:10:31PM +0530, Jagan Teki wrote:
> On Thu, Jan 2, 2020 at 4:24 PM Maxime Ripard <mripard@xxxxxxxxxx> wrote:
> >
> > On Tue, Dec 31, 2019 at 06:35:21PM +0530, Jagan Teki wrote:
> > > TCON LCD0, LCD1 in allwinner R40, are used for managing
> > > LCD interfaces like RGB, LVDS and DSI.
> > >
> > > Like TCON TV0, TV1 these LCD0, LCD1 are also managed via
> > > tcon top.
> > >
> > > Add support for it, in tcon driver.
> > >
> > > Signed-off-by: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx>
> > > ---
> > > Changes for v3:
> > > - none
> > >
> > >  drivers/gpu/drm/sun4i/sun4i_tcon.c | 8 ++++++++
> > >  1 file changed, 8 insertions(+)
> > >
> > > diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c
> > > index fad72799b8df..69611d38c844 100644
> > > --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
> > > +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
> > > @@ -1470,6 +1470,13 @@ static const struct sun4i_tcon_quirks sun8i_a83t_tv_quirks = {
> > >       .has_channel_1          = true,
> > >  };
> > >
> > > +static const struct sun4i_tcon_quirks sun8i_r40_lcd_quirks = {
> > > +     .supports_lvds          = true,
> > > +     .has_channel_0          = true,
> > > +     /* TODO Need to support TCON output muxing via GPIO pins */
> > > +     .set_mux                = sun8i_r40_tcon_tv_set_mux,
> >
> > What is this muking about? And why is it a TODO?
>
> Muxing similar like how TCON TOP handle TV0, TV1 I have reused the
> same so-that it would configure de port selection via
> sun8i_tcon_top_de_config
>
> TCON output muxing have gpio with GPIOD and GPIOH bits, which select
> which of LCD or TV TCON outputs to the LCD function pins. I have
> marked these has TODO for further support as mentioned by Chen-Yu in
> v1[1].

It should be in the commit log.

What's the plan to support that when needed? And that means that the
LCD and TV outputs are mutually exclusive? We should at the very least
check that both aren't enabled at the same time.

Maxime

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