Re: [PATCH v5 1/7] dt-bindings: display: verisilicon,dc: generalize for single-output variants

[Conor Dooley <conor@kernel.org>]

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On Thu, Jun 25, 2026 at 05:44:43PM +0800, Joey Lu wrote:
> The verisilicon,dc binding was originally written for the T-Head TH1520
> SoC carrying a DC8200, and hard-codes five clocks, three resets and two
> output ports.
> 
> Add the Nuvoton MA35D1 DCUltraLite (nuvoton,ma35d1-dcu) to the binding.
> The DCUltraLite uses only two clocks (core, pix0) and one reset (core),
> with a single output port.
> 
> Use allOf/if blocks to express per-variant constraints rather than
> hard-coding the DC8200 topology at the top level.  Each compatible's
> block constrains the clock and reset item counts; the nuvoton block
> additionally overrides clock-names to the two names it actually uses.
> 
> Signed-off-by: Joey Lu <a0987203069@gmail.com>
> ---
>  .../bindings/display/verisilicon,dc.yaml      | 57 +++++++++++++++++++
>  1 file changed, 57 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/display/verisilicon,dc.yaml b/Documentation/devicetree/bindings/display/verisilicon,dc.yaml
> index 9dc35ab973f2..1e751f3c7ce8 100644
> --- a/Documentation/devicetree/bindings/display/verisilicon,dc.yaml
> +++ b/Documentation/devicetree/bindings/display/verisilicon,dc.yaml
> @@ -17,6 +17,7 @@ properties:
>      items:
>        - enum:
>            - thead,th1520-dc8200
> +          - nuvoton,ma35d1-dcu
>        - const: verisilicon,dc # DC IPs have discoverable ID/revision registers
>  
>    reg:
> @@ -77,6 +78,62 @@ required:
>    - clock-names
>    - ports
>  
> +allOf:
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: thead,th1520-dc8200
> +    then:
> +      properties:
> +        clocks:
> +          minItems: 5
> +          maxItems: 5
> +
> +        clock-names:
> +          minItems: 5
> +          maxItems: 5

All the maxItems here repeat the maximum constraint and do nothing.

Since you didn't change the minimum constraint at the top level, your
minItems also do nothing.

> +
> +        resets:
> +          minItems: 3
> +          maxItems: 3
> +
> +        reset-names:
> +          minItems: 3
> +          maxItems: 3
> +
> +      required:
> +        - resets
> +        - reset-names

Both conditional sections have this, but the original binding doesn't
require these for the thead device. This is a functional change
therefore and shouldn't be in a patch calling itself "generalise for
single ended variants".

FWIW, adding your new compatible shouldn't really be in a patch with
that subject either, it really should say "add support for nuvoton
ma35d1" or something.

> +
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: nuvoton,ma35d1-dcu
> +    then:
> +      properties:
> +        clocks:
> +          minItems: 2

Anything that updates the minimum constraint should be done at the top
level of this schema. The conditional section should then tighten the
constraint, in this case that means only having maxItems.

> +          maxItems: 2
> +
> +        clock-names:
> +          items:
> +            - const: core
> +            - const: pix0

Does this even work when the top level schema thinks clock 2 should be
called axi?

> +
> +        resets:
> +          minItems: 1
> +          maxItems: 1
> +
> +        reset-names:
> +          items:
> +            - const: core

This is just maxItems: 1.

pw-bot: changes-requested

Thanks,
Conor.

> +
> +      required:
> +        - resets
> +        - reset-names
> +
>  additionalProperties: false
>  
>  examples:
> -- 
> 2.43.0
> 

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