[PATCH v4 13/18] dt-bindings: usb-switch: Extend for DisplayPort altmode

[Dmitry Baryshkov]

On Sat, Aug 31, 2024 at 09:06:51PM GMT, Stephen Boyd wrote:
> Extend the usb-switch binding to support DisplayPort (DP) alternate
> modes. A third port for the DP signal is necessary when a mode-switch is
> muxing USB and DP together onto a usb type-c connector. Add data-lanes
> to the usbc output node to allow a device using this binding to remap
> the data lanes on the output. Add an example to show how this new port
> can be used.
> 
> Reviewed-by: Rob Herring (Arm) <robh at kernel.org>
> Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt at linaro.org>
> Cc: Conor Dooley <conor+dt at kernel.org>
> Cc: Benson Leung <bleung at chromium.org>
> Cc: Guenter Roeck <groeck at chromium.org>
> Cc: Prashant Malani <pmalani at chromium.org>
> Cc: Tzung-Bi Shih <tzungbi at kernel.org>
> Cc: <devicetree at vger.kernel.org>
> Cc: <chrome-platform at lists.linux.dev>
> Cc: Pin-yen Lin <treapking at chromium.org>
> Signed-off-by: Stephen Boyd <swboyd at chromium.org>
> ---
>  .../devicetree/bindings/usb/usb-switch.yaml   | 89 +++++++++++++++++++
>  1 file changed, 89 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/usb/usb-switch.yaml b/Documentation/devicetree/bindings/usb/usb-switch.yaml
> index f5dc7e23b134..816f295f322f 100644
> --- a/Documentation/devicetree/bindings/usb/usb-switch.yaml
> +++ b/Documentation/devicetree/bindings/usb/usb-switch.yaml
> @@ -52,6 +52,14 @@ properties:
>            endpoint:
>              $ref: '#/$defs/usbc-in-endpoint'
>  
> +      port at 2:
> +        $ref: /schemas/graph.yaml#/$defs/port-base
> +        unevaluatedProperties: false
> +
> +        properties:
> +          endpoint:
> +            $ref: '#/$defs/dp-endpoint'

Is it a separate port or is it an endpoint of the same upstream-facing
(non-connector-facing) SS port?

> +
>  oneOf:
>    - required:
>        - port
> @@ -65,6 +73,19 @@ $defs:
>      $ref: /schemas/graph.yaml#/$defs/endpoint-base
>      description: Super Speed (SS) output endpoint to a type-c connector
>      unevaluatedProperties: false
> +    properties:
> +      data-lanes:
> +        $ref: /schemas/types.yaml#/definitions/uint32-array
> +        description: |
> +          An array of physical USB Type-C data lane indexes.
> +          - 0 is SSRX1 lane
> +          - 1 is SSTX1 lane
> +          - 2 is SSTX2 lane
> +          - 3 is SSRX2 lane
> +        minItems: 4
> +        maxItems: 4
> +        items:
> +          maximum: 3

What is the usecase to delare less than 4 lanes going to the USB-C
connector?

>  
>    usbc-in-endpoint:
>      $ref: /schemas/graph.yaml#/$defs/endpoint-base
> @@ -79,7 +100,75 @@ $defs:
>          items:
>            maximum: 8
>  
> +  dp-endpoint:
> +    $ref: /schemas/graph.yaml#/$defs/endpoint-base
> +    description: DisplayPort (DP) input from the DP PHY
> +    unevaluatedProperties: false
> +    properties:
> +      data-lanes:
> +        $ref: /schemas/types.yaml#/definitions/uint32-array
> +        description: |
> +          An array of physical DP data lane indexes
> +          - 0 is DP ML0 lane
> +          - 1 is DP ML1 lane
> +          - 2 is DP ML2 lane
> +          - 3 is DP ML3 lane
> +        oneOf:
> +          - items:
> +              - const: 0
> +              - const: 1
> +          - items:
> +              - const: 0
> +              - const: 1
> +              - const: 2
> +              - const: 3
> +
>  examples:
> +  # A USB + DP mode and orientation switch which muxes DP altmode
> +  # and USB onto a usb-c-connector node.
> +  - |
> +    device {
> +      mode-switch;
> +      orientation-switch;
> +
> +      ports {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        port at 0 {
> +          reg = <0>;
> +          #address-cells = <1>;
> +          #size-cells = <0>;
> +
> +          endpoint {
> +            remote-endpoint = <&usb_c_connector>;
> +            data-lanes = <0 1 2 3>;
> +          };
> +        };
> +
> +        port at 1 {
> +          reg = <1>;
> +          #address-cells = <1>;
> +          #size-cells = <0>;
> +
> +          endpoint {
> +            remote-endpoint = <&usb_ss_phy>;
> +          };
> +        };
> +
> +        port at 2 {
> +          reg = <2>;
> +          #address-cells = <1>;
> +          #size-cells = <0>;
> +
> +          endpoint {
> +            remote-endpoint = <&dp_phy>;
> +            data-lanes = <0 1 2 3>;
> +          };
> +        };
> +      };
> +    };
> +
>    # A USB orientation switch which flips the pin orientation
>    # for a usb-c-connector node.
>    - |
> -- 
> https://chromeos.dev
> 

-- 
With best wishes
Dmitry