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Date:   Wed, 9 Oct 2019 02:05:20 -0400
From:   Brian Masney <masneyb@onstation.org>
To:     Stephen Boyd <sboyd@kernel.org>
Cc:     robdclark@gmail.com, sean@poorly.run, bjorn.andersson@linaro.org,
        a.hajda@samsung.com, Laurent.pinchart@ideasonboard.com,
        airlied@linux.ie, daniel@ffwll.ch, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
        freedreno@lists.freedesktop.org, jonathan@marek.ca,
        Linus Walleij <linus.walleij@linaro.org>
Subject: Re: [PATCH RFC v2 4/5] ARM: dts: qcom: msm8974: add HDMI nodes
Message-ID: <20191009060520.GA14506@onstation.org>
References: <20191007014509.25180-1-masneyb@onstation.org>
 <20191007014509.25180-5-masneyb@onstation.org>
 <20191009022131.604B52070B@mail.kernel.org>
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On Tue, Oct 08, 2019 at 07:21:30PM -0700, Stephen Boyd wrote:
> Quoting Brian Masney (2019-10-06 18:45:08)
> > diff --git a/arch/arm/boot/dts/qcom-msm8974.dtsi b/arch/arm/boot/dts/qcom-msm8974.dtsi
> > index 7fc23e422cc5..af02eace14e2 100644
> > --- a/arch/arm/boot/dts/qcom-msm8974.dtsi
> > +++ b/arch/arm/boot/dts/qcom-msm8974.dtsi
> > @@ -1335,6 +1342,77 @@
> >                                 clocks = <&mmcc MDSS_AHB_CLK>;
> >                                 clock-names = "iface";
> >                         };
> > +
> > +                       hdmi: hdmi-tx@fd922100 {
> > +                               status = "disabled";
> > +
> > +                               compatible = "qcom,hdmi-tx-8974";
> > +                               reg = <0xfd922100 0x35c>,
> > +                                     <0xfc4b8000 0x60f0>;
> > +                               reg-names = "core_physical",
> > +                                           "qfprom_physical";
> 
> Is this the qfprom "uncorrected" physical address? If so, why can't this
> node use an nvmem to read whatever it needs out of the qfprom?

The MSM HDMI code is configured to look for this reg-name here:

https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/msm/hdmi/hdmi.c#L582

There is a qcom,qfprom configured for this board in DTS, however its at
a different address range, so maybe there are multiple qfproms?

https://elixir.bootlin.com/linux/latest/source/arch/arm/boot/dts/qcom-msm8974.dtsi#L424

msm8996.dtsi has the same style of configuration:

https://elixir.bootlin.com/linux/latest/source/arch/arm64/boot/dts/qcom/msm8996.dtsi#L956
https://elixir.bootlin.com/linux/latest/source/arch/arm64/boot/dts/qcom/msm8996.dtsi#L1736

Brian