Re: [PATCH 2/6] dt-bindings: usb: cdns,usb3: support USB devices in DT

[Rob Herring <robh@kernel.org>]

On Thu, Dec 18, 2025 at 04:20:49PM +0100, Alexander Stein wrote:
> Reference usb-hxci.yaml in host mode in order to support on-board USB
> hubs.
> 
> Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
> ---
>  Documentation/devicetree/bindings/usb/cdns,usb3.yaml | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/usb/cdns,usb3.yaml b/Documentation/devicetree/bindings/usb/cdns,usb3.yaml
> index f454ddd9bbaa6..1f7f0adc3b1ed 100644
> --- a/Documentation/devicetree/bindings/usb/cdns,usb3.yaml
> +++ b/Documentation/devicetree/bindings/usb/cdns,usb3.yaml
> @@ -85,6 +85,17 @@ required:
>  
>  allOf:
>    - $ref: usb-drd.yaml#
> +  - if:
> +      properties:
> +        dr_mode:
> +          const: peripheral
> +
> +      required:
> +        - dr_mode
> +    then:
> +      $ref: usb.yaml#
> +    else:
> +      $ref: usb-xhci.yaml#

I would just do:

allOf:
  - $ref: usb-drd.yaml#
  - $ref: usb-xhci.yaml#  (includes usb.yaml)

2 reasons:

As I remember, 'dr_mode' is at least typically what the default mode is 
rather than the only mode the h/w supports.

Even if you are peripheral only, I don't think it is too important to 
disallow otherwise valid properties. (It's random, unspecified 
properties I care about.)

Rob