Hi Rob, On Tue, Oct 15, 2024 at 02:44:18PM -0500, Rob Herring wrote: > On Tue, Oct 15, 2024 at 02:28:06PM +0300, Laurent Pinchart wrote: > > 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. > > There are 3 options: > > - no $ref => additionalProperties > - has a $ref: > - additionalProperties and list ref-ed properties > - unevaluatedProperties and don't list ref-ed properties > > I do debate (with myself) Those are the best and worst debates at the same time :-) > that that is too complicated as many don't > understand the difference. We could go back to always using > additionalProperties which is what we had before unevaluatedProperties > was added. The other option is always use unevaluatedProperties. 2 > things have stopped me from going that route. I don't care to fix > 'additionalProperties' treewide which would be necessary to implement a > meta-schema or check that unevaluatedProperties is used. It's not > something I want to manually check in reviews. The other reason is just > to not change what the rules are again. > > > > >> > > > >> 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. > > This topic is just one piece of validation. A property being used that's > defined, but meaningless for a device is low on the list of what I care > about validating. I can't see how it would cause an actual problem? A > driver is going to read the property and do what with it? Could it be an > ABI issue ever? I can't see how other than a driver failing for some > reason if it finds the property, but that seems a bit far fetched. I agree the risk of issues at runtime is quite low. My personal take on this is that the additional complexity of specifying "$prop: true" in the bindings is low (for me at least), and the increased correctness in DT sources to avoid confusion for DT readers is worth it. I also like how more explicit bindings cleary show in a single place what properties are expected, making it easier for DT authors. That's a personal opinion though. -- Regards, Laurent Pinchart
