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From:   Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Date:   Fri, 8 Dec 2023 13:04:18 +0200
Message-ID: <CAA8EJpoboN85bLiayXJgn5iwh+Gn0OtK0aZ26ZJu9H3xkTT2Tw@mail.gmail.com>
Subject: Re: [PATCH v3 2/3] dt-bindings: phy: qcom-edp: Add X1E80100 PHY compatibles
To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc:     Konrad Dybcio <konrad.dybcio@linaro.org>,
        Abel Vesa <abel.vesa@linaro.org>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Vinod Koul <vkoul@kernel.org>,
        Kishon Vijay Abraham I <kishon@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Abhinav Kumar <quic_abhinavk@quicinc.com>,
        Johan Hovold <johan@kernel.org>, linux-arm-msm@vger.kernel.org,
        linux-phy@lists.infradead.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
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On Fri, 8 Dec 2023 at 09:47, Krzysztof Kozlowski
<krzysztof.kozlowski@linaro.org> wrote:
>
> On 07/12/2023 20:16, Konrad Dybcio wrote:
> >
> >
> > On 12/7/23 17:51, Krzysztof Kozlowski wrote:
> >
> > [...]
> >
> >>> +allOf:
> >>> +  - if:
> >>> +      properties:
> >>> +        compatible:
> >>> +          contains:
> >>> +            enum:
> >>> +              - qcom,x1e80100-dp-phy
> >>> +    then:
> >>> +      properties:
> >>> +        phy-type:
> >>> +          description: DP (default) or eDP type
> >>
> >> Properties must be defined in top-level "properties:" block. In
> >> allOf:if:then you only disallow them for other variants.
> >>
> >>> +          enum: [ 6, 13 ]
> >>> +          default: 6
> >>
> >> Anyway, I was thinking this should be rather argument to phy-cells.
> > I'm not sure I'm for this, because the results would be:
> >
> > --- device.dts ---
> > &dp_controller0 {
> >      phys = <&dp_phy0 PHY_EDP>;
> > };
> >
> > &dp_controller1 {
> >      phys = <&dp_phy1 PHY_DP>;
> > };
> > ------------------
> >
> > as opposed to:
> >
> > --- device.dts ---
> > &dp_phy0 {
> >      phy-type <PHY_EDP>;
> > };
> >
> > &dp_phy1 {
> >      phy-type = <PHY_DP>;
> > };
> > ------------------
>
> Which is exactly what I proposed/wanted to see.
>
> >
> > i.e., we would be saying "this board is connected to this phy
> > instead" vs "this phy is of this type on this board".
> >
> > While none of them really fit the "same hw, different config"
> > situation, I'd vote for the latter one being closer to the
> > truth
>
> Then maybe I miss the bigger picture, but commit msg clearly says:
> "multiple PHYs that can work in both eDP or DP mode"
>
> If this is not the case, describe the hardware correctly in the commit
> msg, so people will not ask stupid questions...

There are multiple PHYs (each of them at its own address space). Each
of the PHYs in question can be used either for the DisplayPort output
(directly or through the USB-C) or to drive the eDP panel.

Same applies to the displayport-controller. It can either drive the DP
or eDP output, hardware-wise it is the same.

-- 
With best wishes
Dmitry