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

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Date:   Tue, 2 Jan 2018 11:26:55 +0100
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        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

On Tue, Jan 2, 2018 at 10:37 AM, Geert Uytterhoeven
<geert@...ux-m68k.org> wrote:
> 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.

Plus, I'm not going to apply the WAKEUP_PATH thing just yet.

At least not in its current version.

Thanks,
Rafael