Re: [PATCH v4 2/3] dt-bindings: display: Fix BCM2835 HVS bindings for BCM2712

[Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>]

On Thu, 19 Dec 2024 at 12:14, Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote:
>
> On 19/12/2024 12:54, Dave Stevenson wrote:
> > Hi Krzysztof
> >
> > On Thu, 19 Dec 2024 at 08:42, Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote:
> >>
> >> On Wed, Dec 18, 2024 at 02:48:33PM +0000, Dave Stevenson wrote:
> >>> Commit 6cfcbe548a3a ("dt-bindings: display: Add BCM2712 HVS bindings")
> >>> added the compatible string for BCM2712, but missed out that
> >>> the number of interrupts and clocks changed too, and both need to be
> >>> named.
> >>>
> >>> Update to validate clock, interrupts, and their names for the variants.
> >>>
> >>> Fixes: 6cfcbe548a3a ("dt-bindings: display: Add BCM2712 HVS bindings")
> >>> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> >>> ---
> >>>  .../bindings/display/brcm,bcm2835-hvs.yaml         | 84 ++++++++++++++++++----
> >>>  1 file changed, 70 insertions(+), 14 deletions(-)
> >>>
> >>> diff --git a/Documentation/devicetree/bindings/display/brcm,bcm2835-hvs.yaml b/Documentation/devicetree/bindings/display/brcm,bcm2835-hvs.yaml
> >>> index f91c9dce2a44..fd25ee5ce301 100644
> >>> --- a/Documentation/devicetree/bindings/display/brcm,bcm2835-hvs.yaml
> >>> +++ b/Documentation/devicetree/bindings/display/brcm,bcm2835-hvs.yaml
> >>> @@ -20,11 +20,20 @@ properties:
> >>>      maxItems: 1
> >>>
> >>>    interrupts:
> >>> -    maxItems: 1
> >>> +    minItems: 1
> >>> +    maxItems: 3
> >>> +
> >>> +  interrupt-names:
> >>> +    minItems: 1
> >>> +    maxItems: 3
> >>>
> >>>    clocks:
> >>> -    maxItems: 1
> >>> -    description: Core Clock
> >>> +    minItems: 1
> >>> +    maxItems: 2
> >>> +
> >>> +  clock-names:
> >>> +    minItems: 1
> >>> +    maxItems: 2
> >>>
> >>>  required:
> >>>    - compatible
> >>> @@ -33,17 +42,64 @@ required:
> >>>
> >>>  additionalProperties: false
> >>>
> >>> -if:
> >>> -  properties:
> >>> -    compatible:
> >>> -      contains:
> >>> -        enum:
> >>> -          - brcm,bcm2711-hvs
> >>> -          - brcm,bcm2712-hvs
> >>> -
> >>> -then:
> >>> -  required:
> >>> -    - clocks
> >>> +allOf:
> >>> +  - if:
> >>> +      properties:
> >>> +        compatible:
> >>> +          contains:
> >>> +            const: brcm,bcm2711-hvs
> >>> +
> >>> +    then:
> >>> +      properties:
> >>> +        clocks:
> >>> +          items:
> >>> +            - description: Core Clock
> >>> +        interrupts:
> >>> +          maxItems: 1
> >>
> >>
> >> clock-names and interrupt-names: false, unless driver needs them but all
> >> this should be explained in the commit msg because it would be a change
> >> to the binding.
> >
> > False it is then.
> >
> > Is there actually a full guide to binding requirements?
> > https://www.kernel.org/doc/html/latest/devicetree/bindings/writing-schema.html
> > is the closest I've found, but it doesn't obviously cover these types
> > of things.
> >
> >>> +
> >>> +      required:
> >>> +        - clocks
> >>> +
> >>> +  - if:
> >>> +      properties:
> >>> +        compatible:
> >>> +          contains:
> >>> +            const: brcm,bcm2712-hvs
> >>> +
> >>> +    then:
> >>> +      properties:
> >>> +        clocks:
> >>> +          minItems: 2
> >>> +          maxItems: 2
> >>> +        clock-names:
> >>> +          items:
> >>> +            - const: core
> >>> +            - const: disp
> >>> +        interrupts:
> >>> +          items:
> >>> +            - description: Channel 0 End of frame
> >>> +            - description: Channel 1 End of frame
> >>> +            - description: Channel 2 End of frame
> >>> +        interrupt-names:
> >>> +          items:
> >>> +            - const: ch0-eof
> >>> +            - const: ch1-eof
> >>> +            - const: ch2-eof
> >>> +      required:
> >>> +        - clocks
> >>> +        - clock-names
> >>> +        - interrupt-names
> >>
> >> My previous comment still stands. Reply to people's feedback instead of
> >> ignoring it.
> >
> > Your previous comment was
> > "Why requiring last two names? Commit msg does not explain that."
> >
> > I didn't ignore it. The driver needs them, and the commit msg states
>
> Uh, so someone added undocumented ABI. How this passed any checks? Or no
> one cared to run validation?

See the cover letter:
"I missed the DT errors from the recent patchset[1] (DT patches
in linux-next via Florian, DRM bindings patches on dri-misc-next)
as Rob's bot report got spam filtered, so this is a fixup set."

> > " but missed out that the number of interrupts and clocks changed too,
> > and *both need to be
> > named*.
>
> Ah, I really did not get this.
>
> > Update to validate clock, interrupts, and *their names* for the variants."
>
> Please say explicitly that since some commit driver needs this. There
> should be a clear reason in the commit msg why you are adding this ABI.

OK, will do.

  Dave

> Best regards,
> Krzysztof