Re: [PATCH] dt-bindings: usb: dwc3-xilinx: Describe the reset constraint for the versal platform

[Conor Dooley <conor@kernel.org>]

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On Thu, Nov 13, 2025 at 12:15:02PM +0000, Pandey, Radhey Shyam wrote:
> [Public]
> 
> > -----Original Message-----
> > From: Conor Dooley <conor@kernel.org>
> > Sent: Thursday, November 13, 2025 12:38 AM
> > To: Pandey, Radhey Shyam <radhey.shyam.pandey@amd.com>
> > Cc: gregkh@linuxfoundation.org; robh@kernel.org; krzk+dt@kernel.org;
> > conor+dt@kernel.org; Simek, Michal <michal.simek@amd.com>; linux-
> > usb@vger.kernel.org; devicetree@vger.kernel.org; linux-arm-
> > kernel@lists.infradead.org; linux-kernel@vger.kernel.org; git (AMD-Xilinx)
> > <git@amd.com>
> > Subject: Re: [PATCH] dt-bindings: usb: dwc3-xilinx: Describe the reset constraint for
> > the versal platform
> >
> > On Wed, Nov 12, 2025 at 09:24:30PM +0530, Radhey Shyam Pandey wrote:
> > > AMD Versal platform USB 2.0 IP controller receives one reset input
> > > from the SoC controlled by the CRL.RST_USB [RESET] register so
> > > accordingly describe reset constraints.
> > >
> > > Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
> > > ---
> > >  .../devicetree/bindings/usb/dwc3-xilinx.yaml  | 43
> > > +++++++++++++++----
> > >  1 file changed, 34 insertions(+), 9 deletions(-)
> > >
> > > diff --git a/Documentation/devicetree/bindings/usb/dwc3-xilinx.yaml
> > > b/Documentation/devicetree/bindings/usb/dwc3-xilinx.yaml
> > > index 36f5c644d959..cd0cc9da242f 100644
> > > --- a/Documentation/devicetree/bindings/usb/dwc3-xilinx.yaml
> > > +++ b/Documentation/devicetree/bindings/usb/dwc3-xilinx.yaml
> > > @@ -50,17 +50,22 @@ properties:
> > >      description:
> > >        A list of phandles for resets listed in reset-names.
> > >
> > > -    items:
> > > -      - description: USB core reset
> > > -      - description: USB hibernation reset
> > > -      - description: USB APB reset
> > > +    oneOf:
> > > +      - items:
> > > +          - description: USB controller reset
> > > +      - items:
> > > +          - description: USB core reset
> > > +          - description: USB hibernation reset
> > > +          - description: USB APB reset
> > >
> > >    reset-names:
> > > -    items:
> > > -      - const: usb_crst
> > > -      - const: usb_hibrst
> > > -      - const: usb_apbrst
> > > -
> > > +    oneOf:
> > > +      - items:
> > > +          - const: usb_crst
> >
> > Why do we need all this oneOf stuff if both have the same first reset?
> > Can't you just set minItems: 1?
> 
> Thanks. I have now set minItems:1 and defined compatible based
> reset min/max constraints. Doing some more validation and
> will send out the v2.
> 
> Example:
> --- a/Documentation/devicetree/bindings/usb/dwc3-xilinx.yaml
> +++ b/Documentation/devicetree/bindings/usb/dwc3-xilinx.yaml
> @@ -47,6 +47,7 @@ properties:
>        - const: ref_clk
> 
>    resets:
> +    minItems: 1
>      description:
>        A list of phandles for resets listed in reset-names.
> 
> @@ -56,6 +57,7 @@ properties:
>        - description: USB APB reset
> 
>    reset-names:
> +    minItems: 1
>      items:
>        - const: usb_crst
>        - const: usb_hibrst
> @@ -95,6 +97,28 @@ required:
>    - resets
>    - reset-names
> 
> +allOf:
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - xlnx,versal-dwc3
> +    then:
> +      properties:
> +        resets:
> +          maxItems: 1
> +        reset-names:
> +          maxItems: 1
> +    else:
> +      properties:
> +        resets:
> +          minItems: 3
> +          maxItems: 3

FWIW, this maxItems is not needed as it matches the number in the list.

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