Message-ID: <c1a2ba5b-4cd9-362b-5a4e-e95a6bf27b3e@linaro.org>
Date:   Sat, 4 Mar 2023 16:59:19 +0000
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Subject: Re: [PATCH v3 1/2] dt-bindings: display/msm: dsi-controller-main: Fix
 deprecated compatible
Content-Language: en-US
To:     Konrad Dybcio <konrad.dybcio@linaro.org>,
        Rob Clark <robdclark@gmail.com>,
        Abhinav Kumar <quic_abhinavk@quicinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Sean Paul <sean@poorly.run>, David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Krishna Manikandan <quic_mkrishn@quicinc.com>
Cc:     Rob Herring <robh@kernel.org>, linux-arm-msm@vger.kernel.org,
        dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20230304-topic-dsi_fixup-v3-0-b8565944d0e6@linaro.org>
 <20230304-topic-dsi_fixup-v3-1-b8565944d0e6@linaro.org>
From:   Bryan O'Donoghue <bryan.odonoghue@linaro.org>
In-Reply-To: <20230304-topic-dsi_fixup-v3-1-b8565944d0e6@linaro.org>
Content-Type: text/plain; charset=UTF-8; format=flowed
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Precedence: bulk

On 04/03/2023 15:55, Konrad Dybcio wrote:
> The point of the previous cleanup was to disallow "qcom,mdss-dsi-ctrl"
> alone. This however didn't quite work out and the property became
> undocumented instead of deprecated. Fix that.
> 
> Fixes: 0c0f65c6dd44 ("dt-bindings: msm: dsi-controller-main: Add compatible strings for every current SoC")
> Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
> ---
>   Documentation/devicetree/bindings/display/msm/dsi-controller-main.yaml | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/display/msm/dsi-controller-main.yaml b/Documentation/devicetree/bindings/display/msm/dsi-controller-main.yaml
> index f195530ae964..d534451c8f7f 100644
> --- a/Documentation/devicetree/bindings/display/msm/dsi-controller-main.yaml
> +++ b/Documentation/devicetree/bindings/display/msm/dsi-controller-main.yaml
> @@ -35,7 +35,7 @@ properties:
>         - items:
>             - enum:
>                 - qcom,dsi-ctrl-6g-qcm2290
> -          - const: qcom,mdss-dsi-ctrl
> +              - qcom,mdss-dsi-ctrl # This should always come with an SoC-specific compatible
>           deprecated: true
>   
>     reg:
> 

This change would make compatible = "qcom,dsi-ctrl-6g-qcm2290", 
"qcom,mdss-dsi-ctrl"; break though

Take this example, I'm going to use 8916 because its easy.

If we apply your change to dsi-controller-main.yaml

diff --git 
a/Documentation/devicetree/bindings/display/msm/dsi-controller-main.yaml 
b/Documentation/devicetree/bindings/display/msm/dsi-controller-main.yaml
index e75a3efe4dace..e93c16431f0a1 100644
--- a/Documentation/devicetree/bindings/display/msm/dsi-controller-main.yaml
+++ b/Documentation/devicetree/bindings/display/msm/dsi-controller-main.yaml
@@ -34,7 +34,7 @@ properties:
        - items:
            - enum:
                - dsi-ctrl-6g-qcm2290
-          - const: qcom,mdss-dsi-ctrl
+              - qcom,mdss-dsi-ctrl
          deprecated: true

    reg:

and then make 8916 == compatible = "qcom,dsi-ctrl-6g-qcm2290", 
"qcom,mdss-dsi-ctrl";

diff --git a/arch/arm64/boot/dts/qcom/msm8916.dtsi 
b/arch/arm64/boot/dts/qcom/msm8916.dtsi
index 0733c2f4f3798..7332b5f66a09d 100644
--- a/arch/arm64/boot/dts/qcom/msm8916.dtsi
+++ b/arch/arm64/boot/dts/qcom/msm8916.dtsi
@@ -1094,7 +1094,7 @@ mdp5_intf1_out: endpoint {
                         };

                         dsi0: dsi@1a98000 {
-                               compatible = "qcom,msm8916-dsi-ctrl",
+                               compatible = "dsi-ctrl-6g-qcm2290",
                                              "qcom,mdss-dsi-ctrl";
                                 reg = <0x01a98000 0x25c>;
                                 reg-names = "dsi_ctrl";

arch/arm64/boot/dts/qcom/apq8016-sbc.dtb: dsi@1a98000: compatible: 
'oneOf' conditional failed, one must be fixed:
	['dsi-ctrl-6g-qcm2290', 'qcom,mdss-dsi-ctrl'] is too long


so compatible = "qcom,dsi-ctrl-6g-qcm2290", "qcom,mdss-dsi-ctrl"; is now 
invalid, not deprecated.

This change also makes compatible = "qcom,dsi-ctrl-6g-qcm2290" or 
compatible = "qcom,mdss-dsi-ctrl" standalone valid compatible which is 
again not what we want.

- enum:
     - qcom,dsi-ctrl-6g-qcm2290
     - qcom,mdss-dsi-ctrl

means either "qcom,dsi-ctrl-6g-qcm2290" or "qcom,mdss-dsi-ctrl" are 
valid compat strings...

As an example if you apply your change and then change the msm8916.dtsi 
to the below

diff --git 
a/Documentation/devicetree/bindings/display/msm/dsi-controller-main.yaml 
b/Documentation/devicetree/bindings/display/msm/dsi-controller-main.yaml
index e75a3efe4dace..e93c16431f0a1 100644
--- a/Documentation/devicetree/bindings/display/msm/dsi-controller-main.yaml
+++ b/Documentation/devicetree/bindings/display/msm/dsi-controller-main.yaml
@@ -34,7 +34,7 @@ properties:
        - items:
            - enum:
                - dsi-ctrl-6g-qcm2290
-          - const: qcom,mdss-dsi-ctrl
+              - qcom,mdss-dsi-ctrl
          deprecated: true

    reg:
diff --git a/arch/arm64/boot/dts/qcom/msm8916.dtsi 
b/arch/arm64/boot/dts/qcom/msm8916.dtsi
index 0733c2f4f3798..829fbe05b5713 100644
--- a/arch/arm64/boot/dts/qcom/msm8916.dtsi
+++ b/arch/arm64/boot/dts/qcom/msm8916.dtsi
@@ -1094,8 +1094,7 @@ mdp5_intf1_out: endpoint {
                         };

                         dsi0: dsi@1a98000 {
-                               compatible = "qcom,msm8916-dsi-ctrl",
-                                            "qcom,mdss-dsi-ctrl";
+                               compatible = "qcom,mdss-dsi-ctrl";
                                 reg = <0x01a98000 0x25c>;
                                 reg-names = "dsi_ctrl";

Then test it with

make O=$BUILDDIR DT_DOC_CHECKER=$DT_DOC_CHECKER 
DT_EXTRACT_EX=$DT_EXTRACT_EX DT_MK_SCHEMA=$DT_MK_SCHEMA 
DT_CHECKER=$DT_CHECKER CHECKER_FLAGS=-W=1 CHECK_DTBS=y qcom/apq8016-sbc.dtb

you'll see no error. However if you just do this

diff --git a/arch/arm64/boot/dts/qcom/msm8916.dtsi 
b/arch/arm64/boot/dts/qcom/msm8916.dtsi
index 0733c2f4f3798..829fbe05b5713 100644
--- a/arch/arm64/boot/dts/qcom/msm8916.dtsi
+++ b/arch/arm64/boot/dts/qcom/msm8916.dtsi
@@ -1094,8 +1094,7 @@ mdp5_intf1_out: endpoint {
                         };

                         dsi0: dsi@1a98000 {
-                               compatible = "qcom,msm8916-dsi-ctrl",
-                                            "qcom,mdss-dsi-ctrl";
+                               compatible = "qcom,mdss-dsi-ctrl";
                                 reg = <0x01a98000 0x25c>;
                                 reg-names = "dsi_ctrl";


and run the same test you get

apq8016-sbc.dtb: dsi@1a98000: compatible: 'oneOf' conditional failed, 
one must be fixed:
	['qcom,mdss-dsi-ctrl'] is too short
	'qcom,mdss-dsi-ctrl' is not one of ['qcom,apq8064-dsi-ctrl', 
'qcom,msm8916-dsi-ctrl', 'qcom,msm8953-dsi-ctrl', 
'qcom,msm8974-dsi-ctrl', 'qcom,msm8996-dsi-ctrl', 
'qcom,msm8998-dsi-ctrl', 'qcom,qcm2290-dsi-ctrl', 
'qcom,sc7180-dsi-ctrl', 'qcom,sc7280-dsi-ctrl', 'qcom,sdm660-dsi-ctrl', 
'qcom,sdm845-dsi-ctrl', 'qcom,sm8150-dsi-ctrl', 'qcom,sm8250-dsi-ctrl', 
'qcom,sm8350-dsi-ctrl', 'qcom,sm8450-dsi-ctrl', 'qcom,sm8550-dsi-ctrl']

---
bod