Re: [PATCH v5 5/6] dt-bindings: display/msm: add stream pixel clock bindings for MST

[Rob Herring <robh@kernel.org>]

On Sat, Aug 09, 2025 at 12:16:19PM +0300, Dmitry Baryshkov wrote:
> From: Abhinav Kumar <quic_abhinavk@quicinc.com>
> 
> On a vast majority of Qualcomm chipsets DisplayPort controller can
> support several MST streams (up to 4x). To support MST these chipsets
> use up to 4 stream pixel clocks for the DisplayPort controller. Expand
> corresponding clock bindings for these platforms and fix example
> schema files to follow updated bindings.
> 
> Note: On chipsets that do support MST, the number of streams supported
> can vary between controllers. For example, SA8775P supports 4 MST
> streams on mdss_dp0 but only 2 streams on mdss_dp1.
> 
> Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
> Signed-off-by: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
>  .../bindings/display/msm/dp-controller.yaml        | 72 +++++++++++++++++++++-
>  .../bindings/display/msm/qcom,sa8775p-mdss.yaml    | 20 ++++--
>  .../bindings/display/msm/qcom,sar2130p-mdss.yaml   | 10 ++-
>  .../bindings/display/msm/qcom,sm8750-mdss.yaml     | 10 ++-
>  .../bindings/display/msm/qcom,x1e80100-mdss.yaml   | 10 ++-
>  5 files changed, 108 insertions(+), 14 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/display/msm/dp-controller.yaml b/Documentation/devicetree/bindings/display/msm/dp-controller.yaml
> index 352824c245224d7b5e096770684795625fc9f146..0122592a3ef5fcfe5a5ff8364b2cb6540a37a8ab 100644
> --- a/Documentation/devicetree/bindings/display/msm/dp-controller.yaml
> +++ b/Documentation/devicetree/bindings/display/msm/dp-controller.yaml
> @@ -58,20 +58,28 @@ properties:
>      maxItems: 1
>  
>    clocks:
> +    minItems: 5
>      items:
>        - description: AHB clock to enable register access
>        - description: Display Port AUX clock
>        - description: Display Port Link clock
>        - description: Link interface clock between DP and PHY
> -      - description: Display Port Pixel clock
> +      - description: Display Port stream 0 Pixel clock
> +      - description: Display Port stream 1 Pixel clock
> +      - description: Display Port stream 2 Pixel clock
> +      - description: Display Port stream 3 Pixel clock
>  
>    clock-names:
> +    minItems: 5
>      items:
>        - const: core_iface
>        - const: core_aux
>        - const: ctrl_link
>        - const: ctrl_link_iface
>        - const: stream_pixel
> +      - const: stream_1_pixel
> +      - const: stream_2_pixel
> +      - const: stream_3_pixel
>  
>    phys:
>      maxItems: 1
> @@ -187,6 +195,68 @@ allOf:
>          required:
>            - "#sound-dai-cells"
>  
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - qcom,sc7180-dp
> +              - qcom,sc7280-dp
> +              - qcom,sc7280-edp
> +              - qcom,sc8180x-edp
> +              - qcom,sc8280xp-edp
> +              - qcom,sm6350-dp
> +    then:
> +      properties:
> +        clocks:
> +          minItems: 5
> +          maxItems: 5
> +    else:
> +      if:
> +        properties:
> +          compatible:
> +            contains:
> +              enum:
> +                # some of SA8775P DP controllers support 4 streams MST,
> +                # others just 2 streams MST
> +                - qcom,sa8775p-dp
> +      then:
> +        oneOf:
> +          - properties:
> +              clocks:
> +                minItems: 8
> +                maxItems: 8
> +          - properties:
> +              clocks:
> +                minItems: 6
> +                maxItems: 6

I don't really care if we catch someone putting in 7 clocks. So just 
do:

clocks:
  minItems: 6
  maxItems: 8

> +      else:
> +        if:
> +          properties:
> +            compatible:
> +              contains:
> +                enum:
> +                  # on these platforms some DP controllers support 2 streams
> +                  # MST, others are SST only
> +                  - qcom,sc8280xp-dp
> +                  - qcom,x1e80100-dp
> +        then:
> +          oneOf:
> +            - properties:
> +                clocks:
> +                  minItems: 6
> +                  maxItems: 6
> +            - properties:
> +                clocks:
> +                  minItems: 5
> +                  maxItems: 5

And here you really didn't need the oneOf.

> +        else:
> +          properties:
> +            clocks:
> +              minItems: 6
> +              maxItems: 6
> +
> +
>  additionalProperties: false
>  
>  examples: