Re: [PATCH 2/2] media: dt-bindings: Use additionalProperties: false for endpoint: properties:

[Laurent Pinchart]

Hi Krzysztof,

On Tue, Oct 15, 2024 at 08:11:18AM +0200, Krzysztof Kozlowski wrote:
> On 14/10/2024 22:29, Laurent Pinchart wrote:
> > On Mon, Oct 14, 2024 at 10:47:31AM +0200, Krzysztof Kozlowski wrote:
> >> On 14/10/2024 10:31, Bryan O'Donoghue wrote:
> >>> On 14/10/2024 08:45, Krzysztof Kozlowski wrote:
> >>>> I do not understand the reasoning behind this change at all. I don't
> >>>> think DT maintainers ever suggested it (in fact, rather opposite:
> >>>> suggested using unevaluatedProps) and I think is not a consensus of any
> >>>> talks.
> >>>
> >>> No there is not but then, how do you give consistent feedback except 
> >>> proposing something to be a baseline.
> >>>
> >>> On the one hand you have upstream additionalProperties: false and 
> >>> unevaluatedProperites: false - it'd be better to have a consistent 
> >>> message on which is to be used.
> >>
> >> Well, I am afraid that push towards additionalProps will lead to grow
> >> common schema (video-interface-devices or video-interfaces) into huge
> >> one-fit-all binding. And that's not good.
> >>
> >> If a common binding for a group of devices encourages you to list its
> >> subset, then it is not that common.
> >>
> >> Solution is to fix that, e.g. split it per classes of devices.
> > 
> > I think splitting large schemas per class is a good idea, but the
> > problem will still exist. For instance, if we were to move the
> > CSI-2-specific properties to a separate schema, that schema would define
> > clock-lanes, data-lanes and clock-noncontinuous. The clock-lanes and
> > clock-noncontinuous properties do not apply to every device, how would
> > we then handle that ? I see three options:
> 
> Why is this a problem? Why is this a problem here, but not in other
> subsystems having exactly the same case?

I won't talk for other subsystems, but I can say I see value in
explicitly expressing what properties are valid for a device in DT
bindings both to inform DT authors and to perform validation on DT
sources. That's the whole point of YAML schemas, and I can't see a good
reason not to use the tooling we have developed when it has an easy way
to do the job.

-- 
Regards,

Laurent Pinchart