From: grygorii.strashko@ti•com (Grygorii Strashko)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v4 1/2] ARM: keystone: pm: switch to use generic pm domains
Date: Thu, 20 Nov 2014 14:03:07 +0200 [thread overview]
Message-ID: <546DD87B.3080806@ti.com> (raw)
In-Reply-To: <CAPDyKFqeZ3YU2OEN4tCOdcQ0pAho67Q8U_eCEOroG9aS0mp+-Q@mail.gmail.com>
On 11/20/2014 01:34 PM, Ulf Hansson wrote:
> On 19 November 2014 14:47, Arnd Bergmann <arnd@arndb•de> 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
next prev parent reply other threads:[~2014-11-20 12:03 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-10 14:59 [PATCH v4 0/2] ARM: keystone: pm: switch to use generic pm domains Grygorii Strashko
2014-11-10 14:59 ` [PATCH v4 1/2] " Grygorii Strashko
2014-11-10 15:06 ` Arnd Bergmann
2014-11-10 17:38 ` Grygorii Strashko
2014-11-10 20:36 ` Arnd Bergmann
2014-11-17 19:14 ` Kevin Hilman
2014-11-17 20:37 ` Arnd Bergmann
2014-11-17 21:50 ` Kevin Hilman
2014-11-18 18:54 ` Grygorii Strashko
2014-11-18 19:32 ` Arnd Bergmann
2014-11-19 11:32 ` Grygorii Strashko
2014-11-19 13:47 ` Arnd Bergmann
2014-11-20 11:34 ` Ulf Hansson
2014-11-20 12:03 ` Grygorii Strashko [this message]
2014-11-20 13:12 ` Ulf Hansson
2014-11-20 13:32 ` Geert Uytterhoeven
2014-11-20 15:32 ` Grygorii Strashko
2014-11-20 20:22 ` Kevin Hilman
2014-11-20 20:26 ` Geert Uytterhoeven
2014-11-20 21:48 ` Kevin Hilman
2014-11-20 21:54 ` Geert Uytterhoeven
2014-11-21 1:30 ` Kevin Hilman
2014-11-21 8:06 ` Geert Uytterhoeven
2014-11-21 18:58 ` Grygorii Strashko
2014-11-21 19:29 ` Kevin Hilman
2014-11-21 20:14 ` Grygorii Strashko
2014-11-24 10:50 ` Arnd Bergmann
2014-11-25 6:44 ` Mike Turquette
2014-11-25 10:33 ` Arnd Bergmann
2014-11-25 11:08 ` Grygorii Strashko
2014-11-25 12:09 ` Arnd Bergmann
2014-11-25 13:30 ` Grygorii Strashko
2014-11-25 14:04 ` Russell King - ARM Linux
2014-11-25 14:53 ` Grygorii Strashko
2014-11-25 16:28 ` santosh shilimkar
2014-11-21 19:20 ` Kevin Hilman
2014-11-21 9:04 ` Geert Uytterhoeven
2014-11-18 2:18 ` santosh.shilimkar at oracle.com
2014-11-10 14:59 ` [PATCH v4 2/2] ARM: dts: keystone: add generic pm controller node Grygorii Strashko
2014-11-10 15:13 ` [PATCH v4 0/2] ARM: keystone: pm: switch to use generic pm domains Grygorii Strashko
2014-11-10 18:51 ` santosh.shilimkar at oracle.com
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