Re: [PATCH v2] arm64/dts/qcom/sc7180: Add Display Port dt node

Stephen Boyd
2021-06-03T21:35:49Z

Quoting khsieh@codeaurora.org (2021-06-03 14:28:37)
> On 2021-06-03 09:53, Bjorn Andersson wrote:
> > On Thu 03 Jun 11:09 CDT 2021, Kuogee Hsieh wrote:
> >
> >> Add DP device node on sc7180.
> >>
> >> Changes in v2:
> >> -- replace msm_dp with dp
> >> -- replace dp_opp_table with opp_table
> >>
> >
> > I'm sorry for those suggestions, I don't like either one of them.
> >
> > And for everything but changes to the DRM code the changelog goes below
> > the --- line, so it's not part of the git history.
> >
> >> Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
> >> ---
> >> arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi | 9 ++++
> >> arch/arm64/boot/dts/qcom/sc7180.dtsi | 78
> >> ++++++++++++++++++++++++++++
> >> 2 files changed, 87 insertions(+)
> >>
> >> diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
> >> b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
> >> index 24d293e..40367a2 100644
> >> --- a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
> >> +++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
> >> @@ -786,6 +786,15 @@ hp_i2c: &i2c9 {
> >> status = "okay";
> >> };
> >>
> >> +&dp {
> >> + status = "okay";
> >> + pinctrl-names = "default";
> >> + pinctrl-0 = <&dp_hot_plug_det>;
> >> + data-lanes = <0 1>;
> >
> > Is it a limitation of the EC in Trogdor that you can only do 2 lanes?
>
> yes,
>

It's not an EC limitation. It's a hardware design decision. We have one
type-c PHY on the sc7180 SoC and we have two type-c ports on the board
so we have decided to only use two lanes for DP and two lanes for USB on
the type-c ports so that both type-c ports work all the time.