Re: [PATCH 3/3] soc: ti: Add ti_sci_pm_domains driver

[Dave Gerlach]

Hi,
On 09/08/2016 12:38 PM, Kevin Hilman wrote:
> Ulf Hansson <ulf.hansson@xxxxxxxxxx> writes:
>
> > [...]
> >
> > > One more idea...
> > >
> > > Since you don't really have a domain (a group of devices), what you
> > > really have is each device having an independent power switch, so as Ulf
> > > suggested, what you really need is for all the devices to share the same
> > > set of runtime PM callbacks that call SCI.  The only difference is the
> > > unique ID.
> > >
> > > Rather than using all of genpd, you could also just use a pm_domain
> > > which is what genpd is built on top of (and also omap_device, which
> > > you're probably familiar with also.)
> >
> > Even if this would work as well, the downside would be that you need
> > to re-invent the parts related to the DT parsing, the probing/removal
> > and attaching/detaching of the device to the PM domain.
> >
> > You probably don't want to go there... :-)
>
> All you'd need to read from DT would be the device-specific ID for
> TI-SCI, and that could be done at bind time with a notifier.  The, in
> that same notifier, if a TI-SCI ID exists, it would get added to the
> pm_domain.
>
> Anyways, your original proposal is much preferred if it can work.  I'm
> just throwing out another option because I really don't like one genpd
> per device.
>
> Kevin

I am first trying to leverage the dev_attach/detach and start/stop 
callbacks that Ulf suggested without creating a single genpd per device 
and it looks like it will work for us. I appreciate the alternative 
suggestions but I agree we'd like to leverage as much of the existing 
genpd framework as we can and avoid going down the omap_device style 
implementation path.

Regards,
Dave