From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [PATCH 2/2] ARM: DT: tegra: pinctrl suspend resume hook Date: Thu, 02 May 2013 12:33:31 -0600 Message-ID: <5182B17B.8050702@wwwdotorg.org> References: <1366740542-26127-1-git-send-email-bbasu@nvidia.com> <1366740542-26127-2-git-send-email-bbasu@nvidia.com> <20130426194908.GA3302@avionic-0098.mockup.avionic-design.de> <77F7DB30C698A44DA22FB222C89DE941A6692E62BD@BGMAIL01.nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <77F7DB30C698A44DA22FB222C89DE941A6692E62BD-kdsAE/FnitNDw2glCA4ptUEOCMrvLtNR@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Bibek Basu Cc: Thierry Reding , "Rafael J. Wysocki" , "linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" , "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-tegra@vger.kernel.org On 04/28/2013 07:42 AM, Bibek Basu wrote: >> -----Original Message----- >> From: Thierry Reding [mailto:thierry.reding-RM9K5IK7kjKj5M59NBduVrNAH6kLmebB@public.gmane.org] >> Sent: Saturday, April 27, 2013 1:19 AM >> To: Bibek Basu >> Cc: Rafael J. Wysocki; linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org; swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org; >> linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; linux- >> pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org >> Subject: Re: [PATCH 2/2] ARM: DT: tegra: pinctrl suspend resume hook >> >> * PGP Signed by an unknown key >> >> On Tue, Apr 23, 2013 at 11:39:02PM +0530, Bibek Basu wrote: >>> Make pinmux as the first node of tegra DT so as to achieve pinctrl as >>> last device to suspend and first device to resume. >> >> I don't think this is a good idea. For one it encodes Linux specific >> implementation details within the device tree. Furthermore I seem to >> remember that the device tree makes no guarantees that the order of nodes >> in the blob is the same as the order in the DTS. >> >> That said I don't have a good alternative. Perhaps one solution would be to >> use suspend_late() and resume_early() for the pinmux driver since they will >> be called after and before the suspend() and resume() callbacks of all other >> devices, respectively. Other than that I wasn't able to find anything about >> forcing a particular order during suspend and resume. >> >> Cc'ing Rafael and the linux-pm mailing list, maybe somebody among them >> knows a proper solution. > > Stephen actually suggested me earlier to add dummy pinmux state on all dependent devices node. And that will make sure that dependency of driver prevails. > I tried that but I was not getting the desired result. > Can anyone tell me correct syntax for adding dummy state? I agree with Thierry that this patch is not the correct approach. A dummy pinctrl state would look something like the following in each affected device node: pinctrl-names = "default"; pinctrl-0 = <>;