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

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Date: Tue, 28 May 2024 12:13:56 -0500
From: Bjorn Andersson <andersson@...nel.org>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.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, May 28, 2024 at 06:12:58PM GMT, Dmitry Baryshkov wrote:
> 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.
> 

Thanks for the explanation, that makes sense.

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

Someone must have managed to use the device in peripheral mode to get
the firmware on there originally...just saying... ;)

Regards,
Bjorn