[PATCH v3 1/2] dt-bindings: display/msm: dsi-controller-main: Fix deprecated compatible

[Konrad Dybcio]

On 4.03.2023 17:59, Bryan O'Donoghue wrote:
> 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 at 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
Intended, they were never supposed to go together, as at the time
before this patchset (and its stated dependency) the fallback
would not be sufficient, the driver wouldn't even probe.

> 
> 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 at 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 at 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.
Intended

> 
> 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.
-ish, it's marked as deprecated but it is valid.

> 
> - 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...
Correct

> 
> 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 at 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
(sidenote: you can just do

make ARCH=.. OUT=.. CHECK_DTBS=y qcom/apq8016-sbc.dtb

the tools are picked up automatically by Kbuild)

> 
> 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 at 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
Yes, correct. It's valid but it's deprecated, so the bindings are
sane. Keep in mind there's an ABI-like aspect to this.

Konrad
> 
> apq8016-sbc.dtb: dsi at 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