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

From: Stephen Boyd <swboyd@chromium.org>
To: Bjorn Andersson <bjorn.andersson@linaro.org>, khsieh@codeaurora.org
Cc: robdclark@gmail.com, sean@poorly.run, vkoul@kernel.org,
	agross@kernel.org, robh+dt@kernel.org,
	devicetree@vger.kernel.org, abhinavk@codeaurora.org,
	aravindh@codeaurora.org, freedreno@lists.freedesktop.org,
	linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] arm64/dts/qcom/sc7180: Add Display Port dt node
Date: Thu, 3 Jun 2021 21:35:34 +0000	[thread overview]
Message-ID: <CAE-0n53B6oa2zUm0h28Z-U4uhdMabZPRFV=h-ffyBKLs_uHZ-Q@mail.gmail.com> (raw)
In-Reply-To: <d3ec375b9cbe72030e240a84a6c7e13d@codeaurora.org>

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.