Re: [RFC PATCH v2 12/19] dt-bindings: gpu: Add compatibles for T-HEAD TH1520 GPU

[Krzysztof Kozlowski <krzk@kernel.org>]

On 23/12/2024 13:55, Michal Wilczynski wrote:
> Add a new SoC-specific compatible ("thead,th1520-gpu") for the T-HEAD
> TH1520 GPU, alongside the Imagination BXM family compatible
> ("img,img-bxm").  This documents the GPU integration on the T-HEAD
> platform.
> 
> Also adjust clock name constraints to accommodate a second clock named
> "sys" instead of "mem" for T-HEAD. This is achieved by changing the
> order, and making the 'sys' appear before 'mem'.
> 
> Provide example of the new GPU node.
> 
> Signed-off-by: Michal Wilczynski <m.wilczynski@samsung.com>
> ---
>  .../bindings/gpu/img,powervr-rogue.yaml       | 32 +++++++++++++++++--
>  1 file changed, 30 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/gpu/img,powervr-rogue.yaml b/Documentation/devicetree/bindings/gpu/img,powervr-rogue.yaml
> index 4078cc816ea1..1eb1c15baec4 100644
> --- a/Documentation/devicetree/bindings/gpu/img,powervr-rogue.yaml
> +++ b/Documentation/devicetree/bindings/gpu/img,powervr-rogue.yaml
> @@ -15,7 +15,10 @@ properties:
>      items:
>        - enum:
>            - ti,am62-gpu
> -      - const: img,img-axe # IMG AXE GPU model/revision is fully discoverable
> +          - thead,th1520-gpu
> +      - enum:
> +          - img,img-axe # IMG AXE GPU model/revision is fully discoverable
> +          - img,img-bxm

This cannot be flexible. You now changed am62-gpu. Look how other
bindings do it: oneOf with two lists.
>  
>    reg:
>      maxItems: 1
> @@ -27,8 +30,8 @@ properties:
>    clock-names:
>      items:
>        - const: core
> -      - const: mem
>        - const: sys
> +      - const: mem

That's ABI break, so no.

Widest constraints - min/maxItems - stay here. In allOf:if:then you
specify the list of items. See:
https://elixir.bootlin.com/linux/v6.11-rc6/source/Documentation/devicetree/bindings/ufs/qcom,ufs.yaml#L127

You will need to adjust existing variants - list the items there.

>      minItems: 1
>  
Best regards,
Krzysztof