On Sat, Oct 07, 2023 at 08:45:41AM +0300, Tony Lindgren wrote: > * Johan Hovold <johan@xxxxxxxxxx> [231006 15:37]: > > On Fri, Oct 06, 2023 at 11:37:12AM +0300, Tony Lindgren wrote: > > > Care to clarify a bit which parts are unclear? The hierarchy of port > > > devices, making serial core manage runtime PM in a generic way, or > > > flushing tx? > > > > I still don't know why you added these two new abstractions (controller > > and port), and that isn't really explained by the commit message either. > > We want serial core to do runtime PM in a generic way and have the usage > count propagate to the parent serial port hardware device. This way we > don't need to care much if the numerous serial port drivers implement > runtime PM or not. Well, except for now we need to check the parent state > for this fix :) That sounds like a lot of complexity to avoid checking if (the single instance of) pm_runtime_get() returns -EACCESS. > We also want serial core to know the serial port to serial port hardware > mapping as we already have multiport devices. The serial core controller > is there to group the serial ports for each serial port hardware device. > We at least now have an option to support devices with multiple controllers > and ports in case we ever happen to see such things. Hypothetical multiple serial controllers should be modelled as separate controllers, but yeah, perhaps we want to describe the ports. > > And if these are indeed needed, then why isn't the serdev controller now > > a child of the "port" device, for example? > > Yes I agree we should now move serdev controller to be a child of the > serial core port device. Then this $subject patch can be reverted. > > Moving serdev controller should also help serdev to deal with multiport > devices I think? It wouldn't help currently I think, since we already resume the controller and don't manage ports individually, but if we now have port devices then it probably should be moved. Johan
