linux-kernel - Re: [PATCH v3 6/6] arm64: dts: qcom: c630: Add Embedded Controller node

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Date: Tue, 28 May 2024 18:12:58 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Bjorn Andersson <andersson@...nel.org>
Cc: Sebastian Reichel <sre@...nel.org>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Hans de Goede <hdegoede@...hat.com>, Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>, 
	"Bryan O'Donoghue" <bryan.odonoghue@...aro.org>, 
	Heikki Krogerus <heikki.krogerus@...ux.intel.com>, 
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Konrad Dybcio <konrad.dybcio@...aro.org>, 
	linux-pm@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org, platform-driver-x86@...r.kernel.org, 
	linux-usb@...r.kernel.org, linux-arm-msm@...r.kernel.org, 
	Nikita Travkin <nikita@...n.ru>
Subject: Re: [PATCH v3 6/6] arm64: dts: qcom: c630: Add Embedded Controller node

On Tue, 28 May 2024 at 18:06, Bjorn Andersson <andersson@...nel.org> wrote:
>
> On Mon, May 27, 2024 at 01:03:51PM GMT, Dmitry Baryshkov wrote:
> > From: Bjorn Andersson <andersson@...nel.org>
>
> Please align this with the S-o-b - feel free to use either form.

Ack. I'll check what went wrong.

>
> >
> > The Embedded Controller in the Lenovo Yoga C630 is accessible on &i2c1
> > and provides battery and adapter status, as well as altmode
> > notifications for the second USB Type-C port.
> >
> > Add a definition for the EC.
> >
> > Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> > ---
> >  .../boot/dts/qcom/sdm850-lenovo-yoga-c630.dts      | 76 ++++++++++++++++++++++
> >  1 file changed, 76 insertions(+)
> >
> > diff --git a/arch/arm64/boot/dts/qcom/sdm850-lenovo-yoga-c630.dts b/arch/arm64/boot/dts/qcom/sdm850-lenovo-yoga-c630.dts
> > index 47dc42f6e936..d975f78eb3ab 100644
> > --- a/arch/arm64/boot/dts/qcom/sdm850-lenovo-yoga-c630.dts
> > +++ b/arch/arm64/boot/dts/qcom/sdm850-lenovo-yoga-c630.dts
> > @@ -370,6 +370,66 @@ zap-shader {
> >  &i2c1 {
> >       status = "okay";
> >       clock-frequency = <400000>;
> > +
> > +     embedded-controller@70 {
> > +             compatible = "lenovo,yoga-c630-ec";
> > +             reg = <0x70>;
> > +
> > +             interrupts-extended = <&tlmm 20 IRQ_TYPE_LEVEL_HIGH>;
> > +
> > +             pinctrl-names = "default";
> > +             pinctrl-0 = <&ec_int_state>;
> > +
> > +             #address-cells = <1>;
> > +             #size-cells = <0>;
> > +
> > +             connector@0 {
> > +                     compatible = "usb-c-connector";
> > +                     reg = <0>;
> > +                     power-role = "dual";
> > +                     data-role = "host";
>
> I was under the impression that this port is wired directly to the SoC
> and as such this would support data role switching as well.
>
> No concern with that, but just out of curiosity, is this not the case?

It is wired through the external Type-C port controller RTS5437, which
also controls the vbus pins, etc. The UCSI firmware reports both ports
as host-only and doesn't implement data role switching. So, having it
as "host" is a safe bet.

I must admit, I also hoped to be able to use this port in gadget mode,
but it seems to be nearly impossible.


-- 
With best wishes
Dmitry