From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Jon Hunter <jonathanh@nvidia.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Kevin Hilman <khilman@kernel.org>,
Rajendra Nayak <rnayak@codeaurora.org>,
Stanimir Varbanov <stanimir.varbanov@linaro.org>,
Stephen Boyd <sboyd@codeaurora.org>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Linux PM list <linux-pm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>
Subject: Re: [RFC PATCH 0/3] PM / Domains: Add support for devices that require multiple domains
Date: Mon, 13 Mar 2017 15:19:39 +0100 [thread overview]
Message-ID: <CAMuHMdVfkD935iJdsmTLA4HTsqXW1M21TxJfGZTmXqSPwQqY8A@mail.gmail.com> (raw)
In-Reply-To: <3e88692d-613b-9c25-2554-7d399c45637a@nvidia.com>
Hi Jon,
On Mon, Mar 13, 2017 at 3:09 PM, Jon Hunter <jonathanh@nvidia.com> wrote:
> On 13/03/17 11:45, Ulf Hansson wrote:
>> +Björn
>>
>> On 13 March 2017 at 10:37, Jon Hunter <jonathanh@nvidia.com> wrote:
>>> Looks like there is still some interest/needs in/for this. Any thoughts
>>> on how we can move this forward?
>>
>> At the Linaro Connect last week, I was talking to Björn, Rajendra and
>> Stephen more about these related issues.
>>
>> It definitely seems like we need to progress with this somehow,
>> meaning we need a solution for being able to associate a device with
>> more than one PM domain. In that context, I don't think genpd based on
>> its current design, is a good fit to solve the problem.
>>
>> Instead I think we need something entirely new (perhaps some code can
>> be borrowed from genpd), which is more similar to the clock/regulator
>> framework. In other words, what you also were suggesting in a earlier
>> reply.
>> In this way, the driver/subsystem gains full flexibility of managing
>> its device's PM domains, which seems like the best future-proof
>> solution.
>
> I agree, I think that that would give us the most flexibility to handle
> whatever scenario. However, I was thinking that we could still use the
> genpd core to register pm-domains with and control. My thought was to
> allow devices to have a bindings with multiple pm-domains ...
>
> dev-xyz {
> ...
> power-domains = <&domain-a>, <&domain-b>;
> };
>
> Then in the genpd core we do having something like ...
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index e697dec9d25b..d1ae6ddf4903 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -2026,6 +2026,15 @@ int genpd_dev_pm_attach(struct device *dev)
> "samsung,power-domain", 0);
> if (!pd_args.np)
> return -ENOENT;
> + } else if (ret > 1) {
> + /*
> + * If there are more than one PM domain defined for a device,
> + * then these need to be manually controlled by the device
> + * driver because the genpd core cannot bind a device with
Which device driver?
The driver for the device that belongs to multiple PM domains?
The PM domain providers?
> + * more than one PM domain.
> + */
> + dev_dbg(dev, "cannot add PM domains, %d detected!\n", ret);
> + return 0;
> }
>
> Then add some new public APIs for getting and controlling the pm-domains ...
>
> struct generic_pm_domain *pm_genpd_get(struct device *dev, char *name);
> - Use 'dev->of_node' to look-up pm-domain if populated, else uses name.
>
> struct generic_pm_domain *of_pm_genpd_get(struct device *dev, int index);
> void pm_genpd_put(struct generic_pm_domain *pd);
> int pm_genpd_power_on(struct generic_pm_domain *pd);
> int pm_genpd_power_off(struct generic_pm_domain *pd);
> - Power on/off APIs would be synchronous types
>
> Are there any potential pitfalls of the above?
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
next prev parent reply other threads:[~2017-03-13 14:19 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-20 10:28 [RFC PATCH 0/3] PM / Domains: Add support for devices that require multiple domains Jon Hunter
2016-09-20 10:28 ` [RFC PATCH 1/3] PM / Domains: Add helper functions for finding and attaching PM domains Jon Hunter
2016-09-20 10:28 ` [RFC PATCH 2/3] PM / Domains: Add support for devices with multiple domains Jon Hunter
2016-09-20 17:54 ` Jon Hunter
2016-09-21 8:53 ` Geert Uytterhoeven
2016-09-21 10:01 ` Jon Hunter
2016-09-21 14:37 ` Jon Hunter
2016-09-21 14:57 ` Geert Uytterhoeven
2016-09-23 12:57 ` Jon Hunter
2016-09-23 14:27 ` Geert Uytterhoeven
2016-09-30 8:05 ` Jon Hunter
2016-10-07 9:14 ` Kevin Hilman
2016-10-10 11:24 ` Jon Hunter
2016-09-20 10:28 ` [RFC PATCH 3/3] dt-bindings: Add support for devices with multiple PM domains Jon Hunter
2016-10-06 6:04 ` [RFC PATCH 0/3] PM / Domains: Add support for devices that require multiple domains Rajendra Nayak
2016-10-06 8:25 ` Jon Hunter
2016-10-06 8:43 ` Rajendra Nayak
2016-10-31 10:44 ` Jon Hunter
2016-11-02 8:56 ` Rajendra Nayak
2016-11-16 13:11 ` Ulf Hansson
2016-11-17 2:31 ` Rajendra Nayak
2016-11-17 15:39 ` Stanimir Varbanov
2016-11-22 13:05 ` Ulf Hansson
2016-11-23 3:48 ` Rajendra Nayak
2016-10-06 12:22 ` Ulf Hansson
2016-10-10 11:18 ` Jon Hunter
2016-10-10 14:04 ` Ulf Hansson
2016-10-11 9:15 ` Jon Hunter
2016-11-03 14:20 ` Jon Hunter
2016-11-16 10:48 ` Jon Hunter
2016-11-16 12:53 ` Rafael J. Wysocki
2016-11-22 11:12 ` Jon Hunter
2016-11-22 13:31 ` Ulf Hansson
2016-11-22 14:28 ` Jon Hunter
2016-11-22 18:26 ` Kevin Hilman
2016-11-22 18:41 ` Jon Hunter
2016-11-24 2:30 ` Stephen Boyd
2016-11-29 11:33 ` Marek Szyprowski
2016-12-15 11:38 ` Jon Hunter
2016-11-22 21:55 ` Rafael J. Wysocki
2016-11-23 9:29 ` Jon Hunter
2016-11-23 13:15 ` Rafael J. Wysocki
2017-02-28 15:18 ` Jon Hunter
2017-02-28 15:29 ` Geert Uytterhoeven
2017-03-13 9:37 ` Jon Hunter
2017-03-13 11:45 ` Ulf Hansson
2017-03-13 14:09 ` Jon Hunter
2017-03-13 14:19 ` Geert Uytterhoeven [this message]
2017-03-13 14:27 ` Jon Hunter
2017-03-13 14:38 ` Geert Uytterhoeven
2017-03-13 14:51 ` Jon Hunter
2017-03-13 14:42 ` Ulf Hansson
2017-03-15 8:57 ` Jon Hunter
2017-03-15 3:47 ` Nayak, Rajendra
2017-03-15 9:03 ` Jon Hunter
2017-03-01 6:19 ` Rajendra Nayak
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