linux-kernel - Re: [PATCH 2/8] gpio: zynq: Wakeup gpio controller when it is used as IRQ controller

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Message-ID: <CACRpkdY1rw92wLA+g4f=LqRr-pRsm0yRW972S6STq3kn7axgWw@mail.gmail.com>
Date:   Tue, 22 Aug 2017 14:57:44 +0200
From:   Linus Walleij <linus.walleij@...aro.org>
To:     Michal Simek <michal.simek@...inx.com>
Cc:     Nava kishore Manne <navam@...inx.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "monstr@...str.eu" <monstr@...str.eu>,
        Borsodi Petr <Petr.Borsodi@...z>,
        Sören Brinkmann <soren.brinkmann@...inx.com>,
        Steffen Trumtrar <s.trumtrar@...gutronix.de>,
        Peter Crosthwaite <peter.crosthwaite@...inx.com>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        Rob Herring <robherring2@...il.com>,
        Josh Cartwright <josh.cartwright@...com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 2/8] gpio: zynq: Wakeup gpio controller when it is used as
 IRQ controller

On Mon, Aug 14, 2017 at 4:33 PM, Michal Simek <michal.simek@...inx.com> wrote:

> I have checked 4.13-rc1 and none is doing anything with clock in these
> irq routines.
> It means it is a question if they have the same issue when device is
> sleeping or we do something wrong.

No but they may get in the future and new drivers may have
the issue.

> It is not a problem to move these calls to core (patch is quite simple)
> but validate that if this is correct on others SoC.
> Do you know if we can validate this on different SoC?

pm_runtime_get() etc are only utilized if the driver
explicitly enable runtime PM, and if they do, they should
have their semantics right for this or their code would be
broken severely.


> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index 9568708a550b..a08a044fa4aa 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -1647,14 +1647,22 @@ static void gpiochip_irq_unmap(struct irq_domain
> *d, unsigned int irq)
>  static int gpiochip_irq_reqres(struct irq_data *d)
>  {
>         struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
> +       int ret;
>
>         if (!try_module_get(chip->gpiodev->owner))
>                 return -ENODEV;
>
> +       ret = pm_runtime_get_sync(chip->parent);
> +       if (ret < 0) {
> +               module_put(chip->gpiodev->owner);
> +               return ret;
> +       }
> +
>         if (gpiochip_lock_as_irq(chip, d->hwirq)) {
>                 chip_err(chip,
>                         "unable to lock HW IRQ %lu for IRQ\n",
>                         d->hwirq);
> +               pm_runtime_put(chip->parent);
>                 module_put(chip->gpiodev->owner);
>                 return -EINVAL;
>         }
> @@ -1666,6 +1674,7 @@ static void gpiochip_irq_relres(struct irq_data *d)
>         struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
>
>         gpiochip_unlock_as_irq(chip, d->hwirq);
> +       pm_runtime_put(chip->parent);
>         module_put(chip->gpiodev->owner);

This looks fine, I'm happy to apply that early for v4.15 after the merge
window (now it is a bit late for radical changes).

Yours,
Linus Walleij