On Fri, Jan 27, 2023 at 10:24:04AM +0200, Tomi Valkeinen wrote: > On 26/01/2023 12:51, Laurent Pinchart wrote: > > On Thu, Jan 26, 2023 at 12:21:06PM +0200, Andy Shevchenko wrote: > > > On Thu, Jan 26, 2023 at 10:41:47AM +0200, Tomi Valkeinen wrote: > > > > On 25/01/2023 17:27, Andy Shevchenko wrote: ... > > > > > But I probably don't understand the ATR structure and what exactly we need to > > > > > pass to it, perhaps it also can be replaced with properties (note, that we have > > > > > some interesting ones that called references, which is an alternative to DT > > > > > phandle). > > > > > > > > Well, maybe this needs a Linux bus implementation. I'm not that familiar > > > > with implementing a bus, but I think that would make it easier to share data > > > > between the deserializer and the serializer. A bus sounds a bit like an > > > > overkill for a 1-to-1 connection, used by a few drivers, but maybe it > > > > wouldn't be too much code. > > > > > > Have you looked at auxiliary bus (appeared a few releases ago in kernel)? > > > > As far as I understand, the auxiliary bus infrastructure is meant for > > use cases where a single hardware device needs to be split into multiple > > logical devices (as in struct device). Platform devices were > > historically (ab)used for this, and the auxiliary bus is meant as a > > cleaner solution. I'm not sure if it would be a good match here, or if > > it would be considered an abuse of the auxiliary bus API. > > The aux bus docs say "A key requirement for utilizing the auxiliary bus is > that there is no dependency on a physical bus, device, register accesses or > regmap support. These individual devices split from the core cannot live on > the platform bus as they are not physical devices that are controlled by > DT/ACPI.", which doesn't sound like a good fit. Thanks for checking! > The deserializer and serializers are currently independent devices and > drivers (the pdata is the only shared thing), but I think we may need > something better here. The devices are more tightly tied together than > "normal" video devices, in my opinion, as the serializer is fully controlled > by the deserializer (including power). > > And if we ever want to implement something like power management, we > probably need something more than what we have now. Although I don't know > how that would be done, as all the peripherals behind the serializer would > also lose power... I believe you have to create a power domain for them and when such device is added, the power domain of it should belong to the serialized. -- With Best Regards, Andy Shevchenko
