linux-kernel - Re: [PATCH v2 3/3] gpio: rcar: Use WAKEUP

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Message-ID: <CAMuHMdVwCmLYxVA0ivrE8MtCUpfVe4PrzTeC7jqqthShOw93JA@mail.gmail.com>
Date:   Tue, 2 Jan 2018 10:37:34 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Linus Walleij <linus.walleij@...aro.org>
Cc:     Ulf Hansson <ulf.hansson@...aro.org>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Linux PM list <linux-pm@...r.kernel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <marc.zyngier@....com>,
        Simon Horman <horms@...ge.net.au>,
        Niklas Soderlund <niklas.soderlund+renesas@...natech.se>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
        linux-gpio@...r.kernel.org,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 3/3] gpio: rcar: Use WAKEUP_PATH driver PM flag

Hi Linus,

On Tue, Jan 2, 2018 at 10:27 AM, Linus Walleij <linus.walleij@...aro.org> wrote:
> On Fri, Dec 29, 2017 at 2:31 PM, Ulf Hansson <ulf.hansson@...aro.org> wrote:
>> From: Geert Uytterhoeven <geert+renesas@...der.be>
>> Since commit ab82fa7da4dce5c7 ("gpio: rcar: Prevent module clock disable
>> when wake-up is enabled"), when a GPIO is used for wakeup, the GPIO block's
>> module clock (if exists) is manually kept running during system suspend, to
>> make sure the device stays active.
>>
>> However, this explicit clock handling is merely a workaround for a failure
>> to properly communicate wakeup information to the PM core. Instead, set the
>> WAKEUP_PATH driver PM flag to indicate that the device is part of the
>> wakeup path, which further also enables middle-layers and PM domains (like
>> genpd) to act on this.
>>
>> In case the device is attached to genpd and depending on if it has an
>> active wakeup configuration, genpd will keep the device active (the clock
>> running) during system suspend when needed. This enables us to remove all
>> explicit clock handling code from the driver, so let's do that as well.
>>
>> Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
>> [Ulf: Converted to use the WAKEUP_PATH driver PM flag]
>> Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
>
> Acked-by: Linus Walleij <linus.walleij@...aro.org>
>
> I guess it is dependent on the other patches?

Yes, it depends on (a) a clock patch queued in clk-next for v4.16, and (b) a PM
patch introducing WAKEUP_PATH.  Applying it prematurely will cause build
or runtime issues.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-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