Re: [RFC][PATCH 0/14] PM / shmobile: Pass power domain information via DT (was: Re: [RFD] PM: Device tree representation of power domains)

From: Rafael J. Wysocki
Date: Sat Jul 21 2012 - 13:12:07 EST

On Monday, July 16, 2012, Rafael J. Wysocki wrote:
> On Thursday, July 05, 2012, Rafael J. Wysocki wrote:
> > On Wednesday, July 04, 2012, Mark Brown wrote:
> > > On Tue, Jul 03, 2012 at 11:02:17PM +0200, Rafael J. Wysocki wrote:
> > >
> > > > I actually don't have any ideas how to do that at the moment, but I wonder
> > > > if anyone has already thought about it?
> > >
> > > > For one, I don't think that representing a power domain as a platform device
> > > > would be a good approach and I'm not sure how to represent the relationships
> > > > between devices and the domains they belong to.
> > >
> > > I guess the OMAP hwmod stuff is the closest thing we've got at the
> > > minute (I don't recall seeing any other implementations in mainline) but
> > > the hwmods themselves don't appear in the DTS right now. They have a
> > > ti,hwmods property on each device naming the hwmod it's in, something
> > > like that seems like a reasonable approach, possibly a reference to
> > > another DT node rather than or as well as a string? That seems fairly
> > > easy.
> >
> > Well, it looks like (and please tell me if I'm wrong) the hwmons are just
> > string attributes that are parsed by the platform-specific code through
> > a platform bus type notifier.
> >
> > We could do that for power domains too, but then each platform wanting to
> > use them would need to implement such a notifier and add its own routine
> > for parsing those strings. Would that be acceptable to everyone concerned?
> I tried to follow the above suggestion and prepared the following patchset
> that allows power domain information for Renesas platforms to be passed as
> "renesas,pmdomain" string attribute of device nodes. It adds functions
> allowing the generic PM domains framework to use names for domain
> identification in various situations and reworks the ARM/shmobile power domains
> support code to used those functions instead of the "raw" ones that take
> domain pointers as their arguments. Finally, it defines a platform bus type
> notifier that will add devices whose DT nodes contain the "renesas,pmdomain"
> attribute to the power domains indicated by it (the value of that attribute
> should be the name of the PM domain to add the device to after it's been
> registered). All of this should allow platform devices to be added to
> appropriate power domains automatically based on the information read from
> a DT.
> The patches are on top of the current linux-next tree.
> I've tested the patches that could be tested on the Mackerel board, except
> for the last one (I'm still working on testing it).

Well, no comments, no objections. Good!

I've just tested [14/14] too and it works as expected.

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