Re: [PATCH v2 1/3] dt-bindings: connector: usb: add altmodes description

Rob Herring
2023-11-16T18:38:05Z

On Tue, Nov 14, 2023 at 12:13:27AM +0200, Dmitry Baryshkov wrote:
> Add description of the USB-C AltModes supported on the particular USB-C
> connector. This is required for devices like Qualcomm Robotics RB5,
> which have no other way to express alternative modes supported by the
> hardware platform.
>
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> ---
> .../bindings/connector/usb-connector.yaml | 36 +++++++++++++++++++
> 1 file changed, 36 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/connector/usb-connector.yaml b/Documentation/devicetree/bindings/connector/usb-connector.yaml
> index 7c8a3e8430d3..1bd51b86906f 100644
> --- a/Documentation/devicetree/bindings/connector/usb-connector.yaml
> +++ b/Documentation/devicetree/bindings/connector/usb-connector.yaml
> @@ -14,6 +14,31 @@ description:
> of a USB interface controller or a separate node when it is attached to both
> MUX and USB interface controller.
>
> +$defs:

I fail to see why we need to use $defs here.

> + altmode-desc:
> + type: object
> + description:
> + A single USB-C Alternative Mode as supported by the USB-C connector logic.
> + properties:
> + svid:
> + $ref: /schemas/types.yaml#/definitions/uint16
> + description: Unique value assigned by USB-IF to the Vendor / AltMode.
> + vdo:
> + $ref: /schemas/types.yaml#/definitions/uint32
> + description: VDO returned by Discover Modes USB PD command.

What's VDO?

These names are a bit short. Types for property names are global
(mostly). Though this patch doesn't make it clear these were already in
use.

> +
> + altmodes-list:
> + type: object
> + description: List of Alternative Modes supported by the schematics on the
> + particular device. This is only necessary if there are no other means to
> + discover supported alternative modes (e.g. through the UCSI firmware
> + interface).
> +
> + patternProperties:
> + "^[a-z][a-z0-9]*$":

Are there standard id's and names? Should we define some so we don't get
'dp', 'displayport', etc.

> + $ref: "#/$defs/altmode-desc"
> + unevaluatedProperties: false
> +
> properties:
> compatible:
> oneOf:
> @@ -171,6 +196,10 @@ properties:
> offer the power, Capability Mismatch is set. Required for power sink and
> power dual role.
>
> + altmodes:
> + $ref: "#/$defs/altmodes-list"
> + unevaluatedProperties: false
> +
> port:
> $ref: /schemas/graph.yaml#/properties/port
> description: OF graph bindings modeling a data bus to the connector, e.g.
> @@ -289,6 +318,13 @@ examples:
> compatible = "usb-c-connector";
> label = "USB-C";
>
> + altmodes {
> + displayport {
> + svid = /bits/ 16 <0xff01>;
> + vdo = <0x00001c46>;
> + };
> + };
> +
> ports {
> #address-cells = <1>;
> #size-cells = <0>;
> --
> 2.42.0
>