On Tue, Jun 10, 2014 at 11:27:45PM +0200, Rafael J. Wysocki wrote: > On Tuesday, June 10, 2014 02:53:26 PM Ulf Hansson wrote: > > On 10 June 2014 14:11, Rafael J. Wysocki <rafael@xxxxxxxxxx> wrote: > > > On Tue, Jun 10, 2014 at 12:51 PM, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: > > >> From: Tomasz Figa <t.figa@xxxxxxxxxxx> > > >> > > >> On a number of platforms, devices are part of controllable power > > >> domains, which need to be enabled before such devices can be accessed > > >> and may be powered down when the device is idle to save some power. > > >> This means that on systems that support power domain control using > > >> generic power domains subsystem, it is necessary to add device to its > > >> power domain before binding a driver to it and remove it from its power > > >> domain after its driver is unbound to make sure that an unused device > > >> does not affect power domain state. > > >> > > >> Since this is not limited to particular busses and specific > > >> archs/platforms, > > > > > > Actually, this isn't correrct. It is limited to the platforms that > > > use Device Trees now. > > > > Correct, we should update the commit message/docs. > > > > > > > > Moreover, it is not consistent with the way we add devices to the ACPI PM > > > domain, which is the ACPI counterpart of this. > > > > I am not sure why you think consistency for ACPI is important here. > > ACPI PM will still be able to handle it's domain/device registering as > > before. There are even other pm_domains that don't use genpd which > > need to handle this themselves. > > My point is that doing things like that in different places for different > firmware interfaces is confusing and likely to lead to coding mistakes in > the future. > > > Or are you saying that you prefer bus notifiers in favour of making > > use of the driver core for this matter? > > Well, please grep for acpi_dev_pm_attach() and see where it is done. > Surely not in drivers/base/dd.c. Also I'm not sure why you're talking > about bus notifiers in this context. > > > Shouldn't the driver core handle most of the common things for a device > > driver? > > Common, yes. Platform-specific, no. > > > Let's compare how the pinctrls are being managed in the driver core, for > > example. > > pinctrl has Device Trees support only at the moment (as far as firmware > interfaces go) and quite frankly I'm not sure if/how we'll need to change > it to cover ACPI as well. > > But for power domains, please keep that stuff away from dd.c. That is, > unless Greg specifically disagrees with me and decides to apply this > patch regardless. :-) Nope, no disagreement from me toward you at all here, keep up the good work :) greg k-h -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
