linux-kernel - Re: [PATCH v3 2/2] arm64: dts: qcom: x1e80100-yoga: Update panel bindings

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Message-ID: <CAF6AEGvDJO7T8DMZLy7764AxO1fqPmUWDm2eh1gqV5T-sTfKOQ@mail.gmail.com>
Date: Tue, 30 Jul 2024 07:26:27 -0700
From: Rob Clark <robdclark@...il.com>
To: Stephan Gerhold <stephan.gerhold@...aro.org>
Cc: linux-arm-msm@...r.kernel.org, Abel Vesa <abel.vesa@...aro.org>, 
	Krzysztof Kozlowski <krzk@...nel.org>, Rob Clark <robdclark@...omium.org>, 
	Bjorn Andersson <andersson@...nel.org>, Konrad Dybcio <konrad.dybcio@...aro.org>, 
	Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" <devicetree@...r.kernel.org>, open list <linux-kernel@...r.kernel.org>, 
	Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Subject: Re: [PATCH v3 2/2] arm64: dts: qcom: x1e80100-yoga: Update panel bindings

On Tue, Jul 30, 2024 at 3:00 AM Stephan Gerhold
<stephan.gerhold@...aro.org> wrote:
>
> On Mon, Jul 29, 2024 at 01:57:25PM -0700, Rob Clark wrote:
> > From: Rob Clark <robdclark@...omium.org>
> >
> > Use the correct panel compatible, and wire up enable-gpio.  It is wired
> > up in the same way as the x1e80100-crd.
> >
> > Signed-off-by: Rob Clark <robdclark@...omium.org>
> > Reviewed-by: Abel Vesa <abel.vesa@...aro.org>
> > ---
> > Note that the power-source differs from the CRD.  Figured that out by
> > diffing $debugfs/gpio.
> >
> >  .../dts/qcom/x1e80100-lenovo-yoga-slim7x.dts    | 17 +++++++++++++++--
> >  1 file changed, 15 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/arm64/boot/dts/qcom/x1e80100-lenovo-yoga-slim7x.dts b/arch/arm64/boot/dts/qcom/x1e80100-lenovo-yoga-slim7x.dts
> > index 70977e9fa266..6f8d52c368a4 100644
> > --- a/arch/arm64/boot/dts/qcom/x1e80100-lenovo-yoga-slim7x.dts
> > +++ b/arch/arm64/boot/dts/qcom/x1e80100-lenovo-yoga-slim7x.dts
> > [...]
> > @@ -669,6 +672,16 @@ &pcie6a_phy {
> >       status = "okay";
> >  };
> >
> > +&pmc8380_3_gpios {
> > +     edp_bl_en: edp-bl-en-state {
> > +             pins = "gpio4";
> > +             function = "normal";
> > +             power-source = <0>; /* 1.8V */
>
> Hm, are you sure the firmware sets it like this?
>
> power-source = <0> is typically VPH, i.e. the main battery supply
> voltage or similar. This will definitely be higher than 1.8V. It seems a
> bit odd to use a variable voltage source for a GPIO...

:shrug:

Board level stuff is a bit outside my area of expertise, but it's what
made /sys/kernel/debug/gpio match for gpiochip3 gpio4 and it's what
made the panel work.  Using <1> resulted in a black screen.

AFAIU Srini has a yoga 7x as well, and perhaps knows how to read ACPI
better than I do, so maybe he can double check.

BR,
-R

> Thanks,
> Stephan