On Sat, Aug 21, 2021 at 08:45:54PM +0300, Dmitry Osipenko wrote: > 20.08.2021 16:08, Ulf Hansson пишет: > ... > >> I suppose if there's really no good way of doing this other than > >> providing a struct device, then so be it. I think the cleaned up sysfs > >> shown in the summary above looks much better than what the original > >> would've looked like. > >> > >> Perhaps an additional tweak to that would be to not create platform > >> devices. Instead, just create struct device. Those really have > >> everything you need (.of_node, and can be used with RPM and GENPD). As I > >> mentioned earlier, platform device implies a CPU-memory-mapped bus, > >> which this clearly isn't. It's kind of a separate "bus" if you want, so > >> just using struct device directly seems more appropriate. > > > > Just a heads up. If you don't use a platform device or have a driver > > associated with it for probing, you need to manage the attachment to > > genpd yourself. That means calling one of the dev_pm_domain_attach*() > > APIs, but that's perfectly fine, ofcourse. > > > >> > >> We did something similar for XUSB pads, see drivers/phy/tegra/xusb.[ch] > >> for an example of how that was done. I think you can do something > >> similar here. > > We need a platform device because we have a platform device driver that > must be bound to the device, otherwise PMC driver state won't be synced > since it it's synced after all drivers of devices that reference PMC > node in DT are probed. I think the causality is the wrong way around. It's more likely that you added the platform driver because you have a platform device that you want to bind against. You can have drivers bind to other types of devices, although it's a bit more work than abusing platform devices for it. There's the "auxiliary" bus that seems like it would be a somewhat better fit (see Documentation/driver-api/auxiliary_bus.rst), though it doesn't look like this fits the purpose exactly. I think a custom bus (or perhaps something that could be deployed more broadly across CCF) would be more appropriate. Looking around, it seems like clk/imx and clk/samsung abuse the platform bus in a similar way, so they would benefit from a "clk" bus as well. Thierry
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