On Tue, Oct 19, 2021 at 04:39:05PM +0200, Marek Vasut wrote: > On 10/19/21 8:49 AM, Laurent Pinchart wrote: > > Hi Marek, > > Hi, > > >>>>>> diff --git a/Documentation/devicetree/bindings/display/bridge/lvds-codec.yaml b/Documentation/devicetree/bindings/display/bridge/lvds-codec.yaml > >>>>>> index 1faae3e323a4..708de84ac138 100644 > >>>>>> --- a/Documentation/devicetree/bindings/display/bridge/lvds-codec.yaml > >>>>>> +++ b/Documentation/devicetree/bindings/display/bridge/lvds-codec.yaml > >>>>>> @@ -79,6 +79,14 @@ properties: > >>>>>> - port@0 > >>>>>> - port@1 > >>>>>> > >>>>>> + pclk-sample: > >>>>>> + description: > >>>>>> + Data sampling on rising or falling edge. > >>>>>> + enum: > >>>>>> + - 0 # Falling edge > >>>>>> + - 1 # Rising edge > >>>>>> + default: 0 > >>>>>> + > >>>>> > >>>>> Shouldn't this be moved to the endpoint, the same way data-mapping is > >>>>> defined as an endpoint property ? > >>>> > >>>> The strapping is a chip property, not port property, so no. > >>> > >>> For this particular chip that's true. I'm still not convinced overall. > >>> For some cases it could be a per-port property > >> > >> Can you be more specific about "some cases" ? > > > > I'm thinking about bridges that could have multiple parallel inputs. > > Can you draft an example how such a binding would look like within the > confines of this lvds-codec.yaml ? > > I also have to wonder how such a hypothetical device would work, would > it serialize two parallel bussed into single LVDS one ? Such a device would require custom bindings I think, as lvds-codec is limited to a single input and a single output. thine,thc63lvd1024.yaml is an example of such a device. > >>> , and moving it there for > >>> lvds-codec too could allow implementing helpers to parse DT properties, > >>> without much drawback for this particular use case as far as I can see. > >>> It's hard to predict the future with certainty of course, so I won't > >>> insist. > >> > >> The DT bindings and the OS drivers are separate thing, we really > >> shouldn't start bending DT bindings so that they would fit nicely with a > >> specific OS driver model. > > > > DT bindings are not holy beings that live in a mythical heaven way above > > the mere mortal drivers, they would be useless without implementations. > > It's not about bending them, which I regularly push against during > > review, but about structuring them in a way that facilitates > > implementations when all other things are equal. > > Note that the pclk-sample isn't a property of the input, but of the > chip, I don't think it is a good idea to say they are equal and conflate > them like so. With a chip that has a single input, that's always the case :-) Anyway, I don't mind a chip-level property for this binding as we're limited to a single port. If other devices need to specify this at the port level, I'm sure we'll be able to cope with the lack of uniformity. > > As I said, despite wondering whether or not it would be better to move > > the property to the endpoint (and that was a genuine open question), I > > won't insist in this case. > > [...] -- Regards, Laurent Pinchart
