[PATCH v2 3/5] dt-bindings: phy: qcom,sc8280xp-qmp-usb43dp-phy: Document static lanes mapping

[Dmitry Baryshkov]

On Tue, Sep 02, 2025 at 11:00:30AM +0200, Neil Armstrong wrote:
> The QMP USB3/DP Combo PHY hosts an USB3 phy and a DP PHY on top
> of a combo glue to route either lanes to the 4 shared physical lanes.
> 
> The routing of the lanes can be:
> - 2 DP + 2 USB3
> - 4 DP
> - 2 USB3
> 
> The layout of the lanes was designed to be mapped and swapped
> related to the USB-C Power Delivery negociation, so it supports
> a finite set of mappings inherited by the USB-C Altmode layouts.
> 
> Nevertheless those QMP Comby PHY can be statically used to
> drive a DisplayPort connector, DP->HDMI bridge, USB3 A Connector,
> etc... without an USB-C connector and no PD events.
> 
> Add a property that documents the static lanes mapping to
> each underlying PHY to allow supporting boards directly
> connecting USB3 and DisplayPort lanes to the QMP Combo
> lanes.
> 
> Signed-off-by: Neil Armstrong <neil.armstrong at linaro.org>
> ---
>  .../phy/qcom,sc8280xp-qmp-usb43dp-phy.yaml         | 29 ++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-usb43dp-phy.yaml b/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-usb43dp-phy.yaml
> index c8bc512df08b5694c8599f475de78679a4438449..12511a462bc6245e0b82726d053d8605148c5047 100644
> --- a/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-usb43dp-phy.yaml
> +++ b/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-usb43dp-phy.yaml
> @@ -76,6 +76,35 @@ properties:
>    mode-switch: true
>    orientation-switch: true
>  
> +  qcom,static-lanes-mapping:
> +    $ref: /schemas/types.yaml#/definitions/uint32-array
> +    minItems: 4
> +    items:
> +      enum:
> +        - 0 # Unconnected (PHY_NONE)
> +        - 4 # USB3 (PHY_TYPE_USB3)
> +        - 6 # DisplayPort (PHY_TYPE_DP)
> +    description:
> +      Describes the static mapping of the Combo PHY lanes, when not used
> +      a in a Type-C dynamic setup using USB-C PD Events to change the mapping.
> +      The 4 lanes can either routed to the underlying DP PHY or the USB3 PHY.
> +      Only 2 of the lanes can be connected to the USB3 PHY, but the 4 lanes can
> +      be connected to the DP PHY.

It feels like this significantly duplicates existing data-lanes
definitions. Can we use that property to express the same semantics?


> +      The numbers corresponds to the PHY Type the lanes are connected to.
> +      The possible combinations are
> +        <0 0 0 0> when none are connected
> +        <4 4 0 6> USB3 and DP single lane
> +        <4 4 6 6> USB3 and DP
> +        <6 6 4 4> DP and USB3
> +        <6 0 4 4> DP and USB3 single lane
> +        <4 4 0 0> USB3 Only
> +        <0 0 4 4> USB3 Only
> +        <6 0 0 0> DP single lane
> +        <0 0 0 6> DP single lane
> +        <6 6 0 0> DP 2 lanes
> +        <0 0 6 6> DP 2 lanes
> +        <6 6 6 6> DP 4 lanes
> +
>    ports:
>      $ref: /schemas/graph.yaml#/properties/ports
>      properties:
> 
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry