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

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Message-ID: <CAJZ5v0j7r_-TJA=n6ohC_iFc_0Tei9nfVZUN5rjB0n0CxYkMgQ@mail.gmail.com>
Date:   Tue, 2 Jan 2018 11:48:55 +0100
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Linux PM <linux-pm@...r.kernel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <marc.zyngier@....com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Simon Horman <horms@...ge.net.au>,
        Niklas Soderlund <niklas.soderlund+renesas@...natech.se>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
        linux-gpio@...r.kernel.org,
        Linux Kernel Mailing List <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 11:44 AM, Geert Uytterhoeven
<geert@...ux-m68k.org> wrote:
> Hi Rafael,
>
> On Tue, Jan 2, 2018 at 11:32 AM, Rafael J. Wysocki <rafael@...nel.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]
>
> Ulf: + killing the DEV_PM_OPS define, increasing kernel size if PM_SUSPEND=n?
>
>>> Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
>
>>> --- a/drivers/gpio/gpio-rcar.c
>>> +++ b/drivers/gpio/gpio-rcar.c
>
>>> @@ -415,6 +402,18 @@ static int gpio_rcar_parse_dt(struct gpio_rcar_priv *p, unsigned int *npins)
>>>         return 0;
>>>  }
>>>
>>> +#ifdef CONFIG_PM_SLEEP
>>> +static int gpio_rcar_suspend(struct device *dev)
>>> +{
>>> +       struct gpio_rcar_priv *p = dev_get_drvdata(dev);
>>> +
>>> +       dev_pm_set_driver_flags(dev, p->wakeup_path ? DPM_FLAG_WAKEUP_PATH : 0);
>>
>> Why don't you simply set dev->power.wakeup_path here?
>
> That's what my v1 did (https://patchwork.kernel.org/patch/10050995/).

I very much prefer this one. :-)

What's wrong with it?

Thanks,
Rafael