[PATCH v3 4/5] dt-bindings: display/msm: add stream pixel clock bindings for MST
Krzysztof Kozlowski
krzysztof.kozlowski at linaro.org
Fri Jul 18 07:26:34 UTC 2025
On Thu, Jul 17, 2025 at 04:28:46PM -0700, Jessica Zhang wrote:
> From: Abhinav Kumar <quic_abhinavk at quicinc.com>
>
> On some chipsets such as qcom,sa8775p-dp, qcom,sm8650-dp and some more,
> the display port controller can support more than one pixel stream
> (multi-stream transport).
>
> These chipsets can support up to 4 stream pixel clocks for display port
> controller. To support MST on these platforms, add the appropriate
> stream pixel clock bindings
>
> Since this mode is not supported on all chipsets, add exception
> rules and min/max items to clearly mark which chipsets support
> only SST mode (single stream) and which ones support MST.
>
> 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.
>
> In addition, many chipsets depend on the "sm8350-dp" compatibility
> string but not all (ex. SM6350) support MST. Because of these reasons,
> the min/maxItem for MST-supported platforms is a range of 5-8.
Then you need to rework if:. Don't use contains for the sm8350-dp, but
list the front compatibles supporting.
>
> Signed-off-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
> Signed-off-by: Jessica Zhang <jessica.zhang at oss.qualcomm.com>
> ---
> .../bindings/display/msm/dp-controller.yaml | 36 +++++++++++++++++++++-
> .../bindings/display/msm/qcom,sa8775p-mdss.yaml | 10 ++++--
> .../bindings/display/msm/qcom,sar2130p-mdss.yaml | 6 ++--
> .../bindings/display/msm/qcom,sc7280-mdss.yaml | 6 ++--
> .../bindings/display/msm/qcom,sm8750-mdss.yaml | 6 ++--
> .../bindings/display/msm/qcom,x1e80100-mdss.yaml | 6 ++--
> 6 files changed, 59 insertions(+), 11 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/display/msm/dp-controller.yaml b/Documentation/devicetree/bindings/display/msm/dp-controller.yaml
> index d8d94f62c102..2893f097df82 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
> @@ -173,6 +181,32 @@ allOf:
> required:
> - "#sound-dai-cells"
>
> + - if:
> + properties:
> + compatible:
> + contains:
> + enum:
> + - qcom,sa8775p-dp
> + - qcom,sc7280-dp
> + - qcom,sc8180x-dp
> + - qcom,sc8280xp-dp
> + - qcom,sc8280xp-edp
> + - qcom,sm8150-dp
> + - qcom,sm8350-dp
> + - qcom,sm8650-dp
> + - qcom,x1e80100-dp
> + then:
> + properties:
> + clocks:
> + minItems: 5
> + maxItems: 8
This if is redundant, drop.
> +
> + else:
> + properties:
> + clocks:
> + minItems: 5
> + maxItems: 5
Only this part has an actual effect.
Best regards,
Krzysztof
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