From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grygorii Strashko Subject: Re: [PATCH v4 1/2] ARM: keystone: pm: switch to use generic pm domains Date: Thu, 20 Nov 2014 14:03:07 +0200 Message-ID: <546DD87B.3080806@ti.com> References: <1415631557-22897-1-git-send-email-grygorii.strashko@ti.com> <1709760.E0jX3Myv0h@wuerfel> <546C7FDD.7030906@ti.com> <2900095.WIocOu7ue2@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-pm-owner@vger.kernel.org To: Ulf Hansson , Arnd Bergmann Cc: Kevin Hilman , 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" , Geert Uytterhoeven , Dmitry Torokhov List-Id: devicetree@vger.kernel.org On 11/20/2014 01:34 PM, Ulf Hansson wrote: > On 19 November 2014 14:47, Arnd Bergmann wrote: >> On Wednesday 19 November 2014 13:32:45 Grygorii Strashko wrote: >>> On 11/18/2014 09:32 PM, Arnd Bergmann wrote: >>>> On Tuesday 18 November 2014 20:54:36 Grygorii Strashko wrote: >>>> >>>> Have one pmdomain driver in the generic code that knows about clocks, >>>> possibly also regulators and pins and just turns them on when needed. >>>> You can have a "simple-pmdomain" or "generic-pmdomain" compatible >>>> string. >>>> >>>> I'm a bit surprised that your pmdomain code looks up the clocks from the >>>> respective device, rather than know about the clocks itself. There is >>>> probably a good reason for this, but I don't see it yet. >>> >>> The keystone 2 uses simple PM schema based on clocks only: >>> - clocks enabled -> dev is active >>> - clocks disabled -> dev is suspended >>> >>> To achieve explained above the Generic clock manipulation PM callbacks framework (pm_clk) is used. >>> - list of managed clocks is filled for each device (for non-DT case the con_id list >>> is specified by platform code like: >>> .con_ids = { "fck", "master", "slave", NULL }, >>> - or - >>> .con_ids = { }, <-- in this case only first clock will be added to pm_clk >>> ) > > According to earlier comments in this thread, device's clocks are > split into "functional" and "PM" clocks. > > If I understand correctly, a typical platform driver will enable it's > "functional" clocks during ->probe() and you want the PM domain to > take care of the "PM" clocks, when the device changes runtime PM > status. > > How will you describe these different set of device clocks in DT? True :( You can dig deeper in the history of this series if you wish. - first Geert Uytterhoeven proposed to use CLK_RUNTIME_PM there https://lkml.org/lkml/2014/11/6/319 - second I proposed to introduce smth. like "clkops-clocks", "pm-clocks" there https://lkml.org/lkml/2014/6/12/436 or "fck-clocks"/"opt-clocks" later. ^failed. So, this implementation picks up all clocks for each device, which is ok for Keystone 2 and, because it's platform specific. >> >> Yes, it would definitely solve the problem that I see with the infrastructure >> code that the current version adds into the platform directory. >> >> The exact binding of course should be reviewed by the pmdomain and >> DT maintainers, to ensure that it is done the best possible way, because >> I assume we will end up using it a lot, and it would be a shame to get >> it slightly wrong. >> >> One possible variation I can think of would be to just use "simple-pmdomain" >> as the compatible string, and use properties in the node itself to decide >> what the domain should control, e.g. >> >> clk_pmdomain: pmdomain { >> compatible = "simple-pmdomain"; >> pmdomain-enable-clocks; >> #power-domain-cells = <0>; >> }; >> clk_regulator_pmdomain: pmdomain { >> compatible = "simple-pmdomain"; >> pmdomain-enable-clocks; >> pmdomain-enable-regulators; >> #power-domain-cells = <0>; >> }; >> >> and then have each device link to one of the nodes as the pmdomain. >> > > That's seems like a good approach to me. Yes, but your previous comment is still actual :( Regards, -grygorii