Hi Laurent,
On Fri, Jun 18, 2021 at 2:24 PM Laurent Pinchart
<laurent.pinchart@xxxxxxxxxxxxxxxx> wrote:
> On Fri, Jun 18, 2021 at 02:07:48PM +0200, Geert Uytterhoeven wrote:
> > On Fri, Jun 18, 2021 at 2:01 PM Ulrich Hecht wrote:
> > > > On 06/18/2021 10:05 AM Geert Uytterhoeven 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...
>
> Sounds like a BSP attempt to model limitations of the DU and/or the PCB
> and implement them in the adv7511 driver. There's similar code in the
> VGA encoder driver that really doesn't belong there.
>
> > > 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?
>
> I don't carry Ulrich's patch in my branch, and last time I checked, HDMI
> output was functional. Do you want me to retest ?
I guess no re-testing is needed, and the properties can just be removed.
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
