From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758016AbaKTU07 (ORCPT ); Thu, 20 Nov 2014 15:26:59 -0500 Received: from mail-la0-f48.google.com ([209.85.215.48]:49782 "EHLO mail-la0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756291AbaKTU05 (ORCPT ); Thu, 20 Nov 2014 15:26:57 -0500 MIME-Version: 1.0 In-Reply-To: <7hh9xtr5ac.fsf@deeprootsystems.com> References: <1415631557-22897-1-git-send-email-grygorii.strashko@ti.com> <1709760.E0jX3Myv0h@wuerfel> <546C7FDD.7030906@ti.com> <2900095.WIocOu7ue2@wuerfel> <546DD87B.3080806@ti.com> <546E0970.5090301@ti.com> <7hh9xtr5ac.fsf@deeprootsystems.com> Date: Thu, 20 Nov 2014 21:26:55 +0100 X-Google-Sender-Auth: VwDmOm1-R3_XoyChmV17acRqfKg Message-ID: Subject: Re: [PATCH v4 1/2] ARM: keystone: pm: switch to use generic pm domains From: Geert Uytterhoeven To: Kevin Hilman Cc: Grygorii Strashko , Ulf Hansson , Arnd Bergmann , ssantosh@kernel.org, "Rafael J. Wysocki" , "linux-pm@vger.kernel.org" , Rob Herring , Grant Likely , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "devicetree@vger.kernel.org" , Dmitry Torokhov Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Kevin, On Thu, Nov 20, 2014 at 9:22 PM, Kevin Hilman wrote: > Grygorii Strashko writes: >> On 11/20/2014 03:32 PM, Geert Uytterhoeven wrote: >>> On Thu, Nov 20, 2014 at 2:12 PM, Ulf Hansson wrote: > > [...] > >>>> So I really think we need to decide on how to address the split of the >>>> device clocks. Before that's done, I don't think it make sense to add >>>> a "simple-pmdomain" compatible, since it will likely not be that many >>>> SoC that can use it. >>>> >>>> So, does anyone have a suggestion on how to deal with the split of the >>>> device clocks into "functional" clocks and into "PM" clocks? >> >> Would it be better to say "functional" and "optional"? In my opinion >> "PM" == "functional". Also, such clock's separation is used in TRM/DM/UMs on HW. > > Yes! I really don't like the name "PM" clock, since it's not at all > obvious what that means. To me, "PM" == "functional" as well. > > So what exactly are we talking about with "PM" clocks, and why are they > "special" when it comes to PM domains? IOW, why are the clocks to be > managed during PM domain transitions for a given device any different > than the clocks that need to be managed for a runtime suspend/resume (or > system suspend/resume) sequence for the same device? (Speaking for my case, shmobile) They're not. The clocks to be managed during PM domain transitions are the same as the clocks that need to be managed for a runtime suspend/resume (or system suspend/resume) sequence. The special thing is that this is more a platform than a driver thing: the same module may have a "PM/functional" clock (that is documented to enable/disable the module) on one Soc, but not on another. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds