Re: [PATCH RFC 3/3] arm64: dts: qcom: x1e78100-lenovo-thinkpad-t14s: add HDMI nodes

[Stephan Gerhold <stephan.gerhold@linaro.org>]

On Fri, Aug 22, 2025 at 02:01:30PM +0300, Dmitry Baryshkov wrote:
> On Thu, Aug 21, 2025 at 03:53:28PM +0200, Neil Armstrong wrote:
> > The Thinkpad T14s embeds a transparent 4lanes DP->HDMI transceiver
> > connected to the third QMP Combo PHY 4 lanes.
> > 
> > Add all the data routing, disable mode switching and specify the
> > QMP Combo PHY should be in DP-Only mode to route the 4 lanes to
> > the underlying DP phy.
> > 
> > Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
> > ---
> >  .../dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi    | 44 ++++++++++++++++++++++
> >  1 file changed, 44 insertions(+)
> > 
> > diff --git a/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi b/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
> > index 4cf61c2a34e31233b1adc93332bcabef22de3f86..5b62b8c3123633360f249e3ecdc8ea23f44e8e09 100644
> > --- a/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
> > +++ b/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
> > @@ -62,6 +62,20 @@ switch-lid {
> >  		};
> >  	};
> >  
> > +
> > +	hdmi-connector {
> > +		compatible = "hdmi-connector";
> > +		type = "a";
> > +		pinctrl-0 = <&hdmi_hpd_default>;
> > +		pinctrl-names = "default";
> [...]
> > +
> > +		port {
> > +			hdmi_con: endpoint {
> > +				remote-endpoint = <&usb_1_ss2_qmpphy_out>;
> 
> Please describe the transparent bridge too. It can be covered by the
> simple-bridge.yaml / simple-bridge.c
> 

I think this isn't the case here(?), but how are we going to handle
devices where we don't know which bridge chip is used? I've seen at
least 3 or 4 different chips already across all X1E laptops and we don't
have schematics for most of them.

Thanks,
Stephan