From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757423Ab2GEUMS (ORCPT ); Thu, 5 Jul 2012 16:12:18 -0400 Received: from ogre.sisk.pl ([193.178.161.156]:55012 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757349Ab2GEUMP (ORCPT ); Thu, 5 Jul 2012 16:12:15 -0400 From: "Rafael J. Wysocki" To: Mark Brown Subject: Re: [RFD] PM: Device tree representation of power domains Date: Thu, 5 Jul 2012 22:17:47 +0200 User-Agent: KMail/1.13.6 (Linux/3.5.0-rc5+; KDE/4.6.0; x86_64; ; ) Cc: Linux PM list , LKML , Matthew Garrett , Magnus Damm , Arnd Bergmann , Grant Likely References: <201207032302.17805.rjw@sisk.pl> <20120704115637.GS4111@opensource.wolfsonmicro.com> In-Reply-To: <20120704115637.GS4111@opensource.wolfsonmicro.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-2" Content-Transfer-Encoding: 7bit Message-Id: <201207052217.48086.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? Rafael