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From:   Stephen Boyd <swboyd@chromium.org>
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Date:   Tue, 26 Apr 2022 14:19:46 -0700
Message-ID: <CAE-0n53Oc2Ni=dgMPLxDXLUzOPXzAQOFm2fTiimTJA_K84M=5g@mail.gmail.com>
Subject: Re: [PATCH v2] arm64: dts: qcom: sc7280: eDP for herobrine boards
To:     Bjorn Andersson <bjorn.andersson@linaro.org>,
        Douglas Anderson <dianders@chromium.org>
Cc:     Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Kuogee Hsieh <quic_khsieh@quicinc.com>,
        Rob Clark <robdclark@chromium.org>,
        linux-arm-msm@vger.kernel.org,
        Sankeerth Billakanti <quic_sbillaka@quicinc.com>,
        Abhinav Kumar <quic_abhinavk@quicinc.com>,
        quic_kalyant@quicinc.com, Matthias Kaehlcke <mka@chromium.org>,
        Andy Gross <agross@kernel.org>,
        Krzysztof Kozlowski <krzk+dt@kernel.org>,
        Rob Herring <robh+dt@kernel.org>, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
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Quoting Douglas Anderson (2022-04-26 12:41:03)
> Add eDP support to herobrine boards, splitting up amongst the
> different files as makes sense. Rationale for the current split of
> things:
> * The eDP connector itself is on qcard. However, not all devices with
>   a qcard will use an eDP panel. Some might use MIPI and, presumably,
>   someone could build a device with qcard that had no display at all.
> * The qcard provides a PWM for backlight that goes to the eDP
>   connector. This PWM is also provided to the board and it's expected
>   that it would be used as the backlight PWM even for herobrine
>   devices with MIPI displays.
> * It's currently assumed that all herobrine boards will have some sort
>   of display, either MIPI or eDP (but not both).
> * We will assume herobrine-rev1 has eDP. The schematics allow for a
>   MIPI panel to be hooked up but, aside from some testing, nobody is
>   doing this and most boards don't have all the parts stuffed for
>   it. The two panels would also share a PWM for backlight, which is
>   weird.
> * herobrine-villager and herobrine-hoglin (crd) also have eDP.
> * herobrine-hoglin (crd) has slightly different regulator setup for
>   the backlight. It's expected that this is unique to this board. See
>   comments in the dts file.
> * There are some regulators that are defined in the qcard schematic
>   but provided by the board like "vreg_edp_bl" and
>   "vreg_edp_3p3". While we could put references to these regulators
>   straight in the qcard.dtsi file, this would force someone using
>   qcard that didn't provide those regulators to provide a dummy or do
>   an ugly /delete-node/. Instead, we'll add references in
>   herobrine.dtsi.
>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> ---

Reviewed-by: Stephen Boyd <swboyd@chromium.org>