Re: [PATCH 1/3] dt-bindings: gpu: nvidia,gk20a: Allow a fuse clock after the reference clock

[Thierry Reding <thierry.reding@kernel.org>]

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On Tue, Oct 13, 2026 at 10:52:08AM -0400, Sasha Levin wrote:
> GM20B needs both its reference clock and the fuse clock while it is
> powered, so allow "fuse" as a fourth clock after "ref".
> 
> Assisted-by: LLM
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
>  Documentation/devicetree/bindings/gpu/nvidia,gk20a.yaml | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/gpu/nvidia,gk20a.yaml b/Documentation/devicetree/bindings/gpu/nvidia,gk20a.yaml
> index 4d856a8b674c..ecbc20e6adec 100644
> --- a/Documentation/devicetree/bindings/gpu/nvidia,gk20a.yaml
> +++ b/Documentation/devicetree/bindings/gpu/nvidia,gk20a.yaml
> @@ -44,6 +44,7 @@ properties:
>        - description: GPU clock
>        - description: Power clock
>        - description: Reference or fuse clock
> +      - description: Fuse clock
>  
>    clock-names:
>      minItems: 2
> @@ -51,6 +52,7 @@ properties:
>        - const: gpu
>        - const: pwr
>        - enum: [ ref, fuse ]
> +      - const: fuse

Technically this now allows:

    clock-names = "gpu", "pwr", "fuse", "fuse";

I think we may need a very explicit version to cover this now, something
like:

    clock-names:
      oneOf:
        # for GK20A, GP10B, and GV11B
        - minItems: 2
          items:
            - const: gpu
            - const: pwr
            - const: fuse

        # for GM20B
        - minItems: 3
          items:
            - const: gpu
            - const: pwr
            - const: ref
            - const: fuse

We may also want to leave out the minItems property because it turns out
the FUSE clock is indeed required, so we'll need to add it to all device
trees anyway to fix this hang.

The exact list of items could also go into the per-SoC/GPU conditional
sections to be very exact.

Thierry

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