Re: [PATCH 2/2] ARM: dts: exynos: tiny4412: add proper panel node

From: Krzysztof Kozlowski <krzk@kernel.org>
To: Frank Lee <tiny.windzz@gmail.com>
Cc: Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Kukjin Kim <kgene@kernel.org>,
	devicetree <devicetree@vger.kernel.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	linux-samsung-soc <linux-samsung-soc@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] ARM: dts: exynos: tiny4412: add proper panel node
Date: Wed, 8 Jan 2020 08:59:28 +0100	[thread overview]
Message-ID: <20200108075928.GA9911@pi3> (raw)
In-Reply-To: <CAEExFWvJx82h1c1QBrQ+DpT4kgEZ0o3q_O7JLbk-1L-iuMGPEw@mail.gmail.com>

On Wed, Jan 08, 2020 at 03:07:25AM +0800, Frank Lee wrote:
> On Tue, Jan 7, 2020 at 5:04 PM Krzysztof Kozlowski <krzk@kernel.org> wrote:
> >
> > On Mon, Jan 06, 2020 at 07:10:03PM +0000, Yangtao Li wrote:
> > > This patch add at070tn92 panel for tiny4412 board.
> >
> > Please fix description as in patch 1.
> >
> > >
> > > Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
> > > ---
> > >  arch/arm/boot/dts/exynos4412-tiny4412.dts | 16 ++++++++++++++++
> > >  1 file changed, 16 insertions(+)
> > >
> > > diff --git a/arch/arm/boot/dts/exynos4412-tiny4412.dts b/arch/arm/boot/dts/exynos4412-tiny4412.dts
> > > index 2b62cb27420c..57f9d09233ad 100644
> > > --- a/arch/arm/boot/dts/exynos4412-tiny4412.dts
> > > +++ b/arch/arm/boot/dts/exynos4412-tiny4412.dts
> > > @@ -66,6 +66,16 @@
> > >                       clock-frequency = <24000000>;
> > >               };
> > >       };
> > > +
> > > +     panel {
> > > +             compatible = "innolux,at070tn92";
> > > +
> > > +             port {
> > > +                     panel_input: endpoint {
> > > +                             remote-endpoint = <&lcdc_output>;
> > > +                     };
> > > +             };
> > > +     };
> > >  };
> > >
> > >  &fimd {
> > > @@ -74,6 +84,12 @@
> > >       #address-cells = <1>;
> > >       #size-cells = <0>;
> > >       status = "okay";
> >
> > One empty space here.
> >
> > > +     port@3 {
> > > +             reg = <3>;
> >
> > Why starting from "3"? Why this is port@3, not just "port"?
> 
> From samsung-fimd.txt:
> ---
> The device node can contain 'port' child nodes according to the bindings defined
> in [2]. The following are properties specific to those nodes:
> - reg: (required) port index, can be:
>                 0 - for CAMIF0 input,
>                 1 - for CAMIF1 input,
>                 2 - for CAMIF2 input,
>                 3 - for parallel output,
>                 4 - for write-back interface
> ---
> 
> I guess it is influenced here.
> https://elixir.bootlin.com/linux/v5.5-rc5/source/drivers/gpu/drm/exynos/exynos_drm_dpi.c#L170
> Without it, lcd is completely black.

Thanks for explanation.

Best regards,
Krzysztof