Re: [PATCH 1/2] dt-bindings: usb: hcd: Add downstream USB ports

[Rob Herring <robh@kernel.org>]

On Wed, Oct 14, 2026 at 07:16:51PM +0900, Chen-Yu Tsai wrote:
> On Wed, Oct 14, 2026 at 5:31 PM <sashiko-bot@kernel.org> wrote:
> >
> > Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> > - [Medium] dt-bindings: usb: port@0 schema constraint bypassed
> > --
> >
> > commit aaa6107663f4d524c266c3a18264c416a86a4bb4
> > Author: Chen-Yu Tsai <wenst@chromium.org>
> >
> > dt-bindings: usb: hcd: Add downstream USB ports
> >
> > This commit adds a "ports" child node to the USB HCD binding to support
> > connecting downstream USB connector nodes via OF graph. It attempts to enforce
> > that USB downstream port numbers start at 1, and updates the address matching
> > for hard-wired downstream devices.
> >
> > > diff --git a/Documentation/devicetree/bindings/usb/usb-hcd.yaml b/Documentation/devicetree/bindings/usb/usb-hcd.yaml
> > > index 45a19d4928afa..24df99dfb243c 100644
> > > --- a/Documentation/devicetree/bindings/usb/usb-hcd.yaml
> > > +++ b/Documentation/devicetree/bindings/usb/usb-hcd.yaml
> > > @@ -29,8 +29,16 @@ properties:
> > >    "#size-cells":
> > >      const: 0
> > >
> > > +  ports:
> > > +    $ref: /schemas/graph.yaml#/properties/ports
> > > +    description: The downstream facing USB ports
> > > +
> > > +    patternProperties:
> > > +      "^port@[1-9a-f][0-9a-f]?$":
> > > +        $ref: /schemas/graph.yaml#/properties/port
> >
> > [Severity: Medium]
> > Does this local constraint actually prevent port@0 from passing validation?
> >
> > Since JSON schema patternProperties only restrict matching nodes, a
> > non-matching node like port@0 will fall back to the generic graph.yaml
> > reference.

This is a common issue we have in graph and ethernet-switch schemas...

> > Because graph.yaml evaluates anything matching ^port(@.*)?$, wouldn't
> > port@0 be evaluated as valid and silently pass, completely bypassing the
> > intent that downstream port numbers start at 1?
> 
> I suspect I need to write it as:
> 
>     ports:
>       properties:
>         port@0: false
>       patternProperties:
>         "^port@[1-9a-f][0-9a-f]?$": ...

You should just not restrict it here so schema is applied to any port 
node and instead restrict the 'reg' values allowed.

Rob