Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755279AbaAVLA1 (ORCPT ); Wed, 22 Jan 2014 06:00:27 -0500 Received: from service87.mimecast.com ([91.220.42.44]:40068 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753600AbaAVLAY convert rfc822-to-8bit (ORCPT ); Wed, 22 Jan 2014 06:00:24 -0500 Date: Wed, 22 Jan 2014 11:00:18 +0000 From: Lorenzo Pieralisi To: Tomasz Figa Cc: Tomasz Figa , "linux-pm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-samsung-soc@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "devicetree@vger.kernel.org" , Greg Kroah-Hartman , "Rafael J. Wysocki" , Pavel Machek , Len Brown , Russell King , Kukjin Kim , Kumar Gala , Ian Campbell , Mark Rutland , Pawel Moll , Rob Herring , Bartlomiej Zolnierkiewicz , Stephen Warren Subject: Re: [PATCH RFC 04/10] base: power: Add generic OF-based power domain look-up Message-ID: <20140122110018.GB24288@e102568-lin.cambridge.arm.com> References: <1389469372-17199-1-git-send-email-tomasz.figa@gmail.com> <1389469372-17199-5-git-send-email-tomasz.figa@gmail.com> <20140116163409.GD25540@e102568-lin.cambridge.arm.com> <52DD5DC5.3000908@samsung.com> MIME-Version: 1.0 In-Reply-To: <52DD5DC5.3000908@samsung.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-OriginalArrivalTime: 22 Jan 2014 11:00:19.0589 (UTC) FILETIME=[23BD0350:01CF1761] X-MC-Unique: 114012211002007601 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/