Re: [PATCH v3 2/9] dt-bindings: display: add verisilicon,dc

Icenowy Zheng
2025-11-27T13:48:19Z

在 2025-11-26星期三的 11:22 +0100，Krzysztof Kozlowski写道：
> On 26/11/2025 10:50, Icenowy Zheng wrote:
> > > > +maintainers:
> > > > +  - Icenowy Zheng <uwu@icenowy.me>
> > > > +
> > > > +properties:
> > > > +  $nodename:
> > > > +    pattern: "^display@[0-9a-f]+$"
> > > > +
> > > > +  compatible:
> > > > +    items:
> > > > +      - enum:
> > > > +          - thead,th1520-dc8200
> > > > +      - const: verisilicon,dc
> > >
> > > I do not see any explanation of exception for generic
> > > compatibles,
> > > maybe
> > > except "self-identification" remark. Rob already pointed this
> > > out, so
> > > be
> > > explicit in commit msg why you are using a generic compatible.
> >
> > Well I only get the meaning of "a SoC specific compatible is
> > required"
> > in his review message.
> >
> > I think my binding now requires both a SoC-specific compatible and
> > a
> > generic compatible, which should be okay to satisfy Rob's original
> > review.
>
> You will get then the same questions for me - what justifies generic
> compatible. You should be on this explicit, because otherwise people
> misinterpret some commits and patches, and they think the generic
> compatible is allowed for them as well.

I came across a comment on Mali Valhall bindings that says `Mali
Valhall GPU model/revision is fully discoverable`, just after the
compatible string.

Should I add a comment like this, or should I make things more clear in
the commit message?

>
> >
> > >
> > > > +
> > > > +  reg:
> > > > +    maxItems: 1
> > > > +
> > > > +  interrupts:
> > > > +    maxItems: 1
> > > > +
> > > > +  clocks:
> > > > +    minItems: 4
> > >
> > > This is not flexible. Device either has or has not these clocks.
> >
> > The existence of all these clocks are verified by diagrams in
> > manuals
>
> So not flexible, then:
>
> > of two different SoCs with DC8200 (T-Head TH1520 and StarFive
> > JH7110).
> >
> > Maybe a explicit `maxItems: 5` is needed here, but as my DT passes
> > dtbs_check, I don't think it's necessary?
>
> No, drop minItems only.
>
> >
> > Or maybe I should drop the flexibility now and use a `minItems: 5`
> > here
> > (and leave DC8000 support as another story)? (The Eswin EIC7700
> > manual
> > does not have a diagram showing external connections of the DC,
> > like
> > the two SoCs I mentioned above).
>
> You document here only the devices explicitly mentioned in the
> binding.
> You cannot add here constraints or clocks for some device which is
> not
> in the binding and I see only th1520 in the binding.
>
> Best regards,
> Krzysztof