Re: [PATCH v6 1/6] dt-bindings: display: verisilicon,dc: add support for nuvoton,ma35d1-dcu

[Joey Lu <a0987203069@gmail.com>]

Icenowy Zheng 於 2026/9/10 下午 03:08 寫道:
> 在 2026-09-10四的 09:52 +0800，Joey Lu写道：
>> Icenowy Zheng 於 2026/9/9 下午 01:44 寫道:
>>> 在 2026-09-08二的 17:28 +0800，Joey Lu写道：
>>>> Add the Nuvoton MA35D1 DCUltraLite (nuvoton,ma35d1-dcu) to the
>>>> binding.
>>>> The DCUltraLite uses only four clocks (core, axi, ahb, pix0) and
>>>> one
>>>> reset (core), with a single output port.
>>>>
>>>> The MA35D1 clock controller gates the core, AXI and AHB clocks
>>>> with a
>>>> single bit, but each remains a distinct clock line feeding the IP
>>>> with
>>>> its own rate constraints, so all four must still be listed
>>>> individually
>>>> in the devicetree; core, axi and ahb happen to share the same
>>>> clock
>>>> phandle.
>>> This is weird, but I must admit that we're limited by the Common
>>> Clock
>>> Framework here, so I cannot give a better solution either.
>>>
>>> Anyway let's settle with the current result.
>>>
>>>> Move the clocks/clock-names minItems to 4 and resets/reset-names
>>>> minItems to 1 at the top level, since that is the lowest count
>>>> any
>>>> supported variant needs.  Add an allOf/if block that tightens the
>>>> constraint back up to the fixed 5-clock/3-reset topology required
>>>> by
>>>> the existing thead,th1520-dc8200 compatible, and another one that
>>>> caps
>>>> the new nuvoton,ma35d1-dcu compatible at the 4-clock/1-reset
>>>> count it
>>>> actually wires up.
>>>>
>>>> Signed-off-by: Joey Lu <a0987203069@gmail.com>
>>>> ---
>>>>    .../bindings/display/verisilicon,dc.yaml      | 44
>>>> +++++++++++++++++++
>>>>    1 file changed, 44 insertions(+)
>>>>
>>>> diff --git
>>>> a/Documentation/devicetree/bindings/display/verisilicon,dc.yaml
>>>> b/Documentation/devicetree/bindings/display/verisilicon,dc.yaml
>>>> index 919a900122012..773966677d0f4 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:
>>>> @@ -26,6 +27,7 @@ properties:
>>>>        maxItems: 1
>>>>    
>>>>      clocks:
>>>> +    minItems: 4
>>>>        items:
>>>>          - description: DC Core clock
>>>>          - description: DMA AXI bus clock
>>>> @@ -34,6 +36,7 @@ properties:
>>>>          - description: Pixel clock of output 1
>>>>    
>>>>      clock-names:
>>>> +    minItems: 4
>>>>        items:
>>>>          - const: core
>>>>          - const: axi
>>>> @@ -42,12 +45,14 @@ properties:
>>>>          - const: pix1
>>>>    
>>>>      resets:
>>>> +    minItems: 1
>>>>        items:
>>>>          - description: DC Core reset
>>>>          - description: DMA AXI bus reset
>>>>          - description: Configuration AHB bus reset
>>>>    
>>>>      reset-names:
>>>> +    minItems: 1
>>>>        items:
>>>>          - const: core
>>>>          - const: axi
>>>> @@ -79,6 +84,45 @@ required:
>>>>      - reset-names
>>>>      - ports
>>>>    
>>>> +allOf:
>>>> +  - if:
>>>> +      properties:
>>>> +        compatible:
>>>> +          contains:
>>>> +            const: thead,th1520-dc8200
>>>> +    then:
>>>> +      properties:
>>>> +        clocks:
>>>> +          minItems: 5
>>>> +
>>>> +        clock-names:
>>>> +          minItems: 5
>>>> +
>>>> +        resets:
>>>> +          minItems: 3
>>>> +
>>>> +        reset-names:
>>>> +          minItems: 3
>>>> +
>>>> +  - if:
>>>> +      properties:
>>>> +        compatible:
>>>> +          contains:
>>>> +            const: nuvoton,ma35d1-dcu
>>>> +    then:
>>>> +      properties:
>>>> +        clocks:
>>>> +          maxItems: 4
>>>> +
>>>> +        clock-names:
>>>> +          maxItems: 4
>>>> +
>>>> +        resets:
>>>> +          maxItems: 1
>>>> +
>>>> +        reset-names:
>>>> +          maxItems: 1
>>> Maybe it's reasonable to restrict max port count to 1 for MA35D1?
>>> Although I am not sure about how to do this...
>>>
>>> Thanks,
>>> Icenowy
>>    I found the same kind of per-compatible port restriction already
>> used
>> upstream in renesas,du.yaml, e.g.:
>>
>>           ports:
>>             properties:
>>               port@2: false
>>               port@3: false
>>             required:
>>               - port@0
>>               - port@1
>>
>> Applied to our binding, that would look like:
>>
>>           ports:
>>             properties:
>>               port@1: false
>>             required:
>>               - port@0
>>
>> in the existing nuvoton,ma35d1-dcu allOf/if/then block, so schema
>> checks
>> would reject a port@1 node on this compatible instead of silently
>> accepting it.
>>
>> Happy to add it if you'd like the schema to enforce this, but wanted
>> to
>> check whether you consider it worth the extra lines given it doesn't
>> reflect an actual bug in any DT today. Let me know which way you'd
>> prefer and I'll fold it into the next version.
> Personally I think this is good, but maybe adding it as an additional
> patch after merging isn't a big problem, because this just plays as
> kind of a safety guard.
>
> Well this depends on how DT binding maintainers think, but as Conor has
> dropped his Ack, this shouldn't be a big issue.
>
> Thanks,
> Icenowy
I'll send the port@1: false restriction as a follow-up patch once this 
series lands.
Thanks!
>> Thanks.
>>>> +
>>>>    additionalProperties: false
>>>>    
>>>>    examples: