lkml.org 
[lkml]   [2014]   [Jan]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH RFC 04/10] base: power: Add generic OF-based power domain look-up
On Mon, Jan 20, 2014 at 05:32:53PM +0000, Tomasz Figa wrote:
> Hi Lorenzo,
>
> On 16.01.2014 17:34, Lorenzo Pieralisi wrote:
> > Hi Tomasz,
> >
> > thank you for posting this series. I would like to use the DT bindings
> > for power domains in the bindings for C-states on ARM:
> >
> > http://comments.gmane.org/gmane.linux.power-management.general/41012
> >
> > and in particular link a given C-state to a given power domain so that the
> > kernel will have a way to actually check what devices are lost upon C-state
> > entry (and for devices I also mean CPU peripheral like PMUs, GIC CPU IF,
> > caches and possibly cpus, all of them already represented with DT nodes).
> >
> > I have a remark:
> >
> > - Can we group device nodes under a single power-domain-parent so that
> > all devices defined under that parent won't have to re-define a
> > power-domain property (a property like interrupt-parent, so to speak)
> >
> > What do you think ?
>
> Hmm, I can see potential benefits of such construct on platforms with
> clear hierarchy of devices, but to make sure I'm getting it correctly,
> is the following what you have in mind?
>
> soc-domain-x@12340000 {
> compatible = "...";
> reg = <...>;
> power-domain-parent = <&power_domains DOMAIN_X>;
>
> device@1000 {
> compatible = "...";
> // inherits power-domain = <&power_domains DOMAIN_X>
> };
>
> device@2000 {
> compatible = "...";
> // inherits power-domain = <&power_domains DOMAIN_X>
> };
> };

Yes, exactly, it could avoid duplicated data. I still have an issue
with nodes that are per-cpu but define just one node (eg PMU), since
a CPU might belong in a power-domain on its own (ie one power domain
per-CPU) and basically this means that arch-timers, PMU & company should
link to multiple power domains, ie one per CPU or we find a way to define
a power domain as "banked".

I need to think about this a bit more, thanks for your feedback.

Lorenzo



\
 
 \ /
  Last update: 2014-01-22 12:41    [W:0.044 / U:3.024 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site