Hi Uli,
On Fri, Jun 18, 2021 at 2:01 PM Ulrich Hecht <uli@xxxxxxxx> wrote:
> > On 06/18/2021 10:05 AM Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
> > On Tue, Sep 25, 2018 at 6:34 PM Laurent Pinchart
> > <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx> wrote:
> > > From: Ulrich Hecht <uli+renesas@xxxxxxxx>
> > >
> > > Adds LVDS decoder, HDMI encoder and connector for the Draak board.
> > >
> > > The LVDS0 and LVDS1 encoders can use the DU_DOTCLKIN0, DU_DOTCLKIN1 and
> > > EXTAL externals clocks. Two of them are provided to the SoC on the Draak
> > > board, hook them up in DT.
> > >
> > > Signed-off-by: Ulrich Hecht <uli+renesas@xxxxxxxx>
> > > Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
> > > Tested-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
> >
> > > --- a/arch/arm64/boot/dts/renesas/r8a77995-draak.dts
> > > +++ b/arch/arm64/boot/dts/renesas/r8a77995-draak.dts
> >
> > > @@ -190,6 +225,43 @@
> > >
> > > };
> > >
> > > + hdmi-encoder@39 {
> > > + compatible = "adi,adv7511w";
> > > + reg = <0x39>, <0x3f>, <0x38>, <0x3c>;
> > > + reg-names = "main", "edid", "packet", "cec";
> > > + interrupt-parent = <&gpio1>;
> > > + interrupts = <28 IRQ_TYPE_LEVEL_LOW>;
> > > +
> > > + /* Depends on LVDS */
> > > + max-clock = <135000000>;
> > > + min-vrefresh = <50>;
> >
> > Where do these two come from? They fail to validate with commit
> > cfe34bb7a770c5d8 ("dt-bindings: drm: bridge: adi,adv7511.txt: convert
> > to yaml").
> > I can't find where it is used in the driver, nor in the driver history.
>
> I have found a prototype patch in my archives that uses these properties. I guess the patch itself didn't make it into the final series, but the properties inadvertently did. I vaguely remember this was supposed to work around an issue with modes that use a higher clock than supported by one of the parts in the display pipeline.
Thanks, I already suspected something like that...
> I would say that if there are no issues with HDMI output, both the patch and the properties are obsolete.
Anyone with a Draak to verify?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
