linux-kernel - Re: [PATCH v4 07/13] i2c: acpi: Use ACPI wake capability bit to set wake

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Date:   Thu, 22 Sep 2022 12:44:12 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Raul Rangel <rrangel@...omium.org>
Cc:     Linux ACPI <linux-acpi@...r.kernel.org>,
        linux-input <linux-input@...r.kernel.org>,
        Tim Van Patten <timvp@...gle.com>,
        Hans de Goede <hdegoede@...hat.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        "Limonciello, Mario" <mario.limonciello@....com>,
        "jingle.wu" <jingle.wu@....com.tw>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Wolfram Sang <wsa@...nel.org>,
        "open list:I2C SUBSYSTEM HOST DRIVERS" <linux-i2c@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 07/13] i2c: acpi: Use ACPI wake capability bit to set
 wake_irq

On Wed, Sep 21, 2022 at 09:18:34AM -0600, Raul Rangel wrote:
> On Tue, Sep 20, 2022 at 6:32 AM Andy Shevchenko
> <andriy.shevchenko@...ux.intel.com> wrote:
> > On Mon, Sep 19, 2022 at 09:59:09AM -0600, Raul E Rangel wrote:

...

> > > +     if (irq_ctx.irq == -ENOENT)
> > > +             irq_ctx.irq = acpi_dev_gpio_irq_wake_get(adev, 0, &irq_ctx.wake_capable);
> >
> > I just realized, that there is an inconsistency on how we fill the wake_capable
> > parameter. In some cases we check for IRQ for an error condition (IRQ not found)
> > and in some the wake_capable still be filled.
> >
> > Here the best approach I believe is to add
> >
> >         if (irq_ctx.irq < 0)
> >                 return irq_ctx.irq;
> >
> > I.o.w. we apply the rule "do not fill the output parameters when it's known
> > to be an error condition".
> >
> > > +     if (wake_capable)
> > > +             *wake_capable = irq_ctx.wake_capable;
> >
> > > +     return irq_ctx.irq;
> >
> 
> I applied the following:
> diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
> index ba64e505183595..1618f5619d5ed9 100644
> --- a/drivers/i2c/i2c-core-acpi.c
> +++ b/drivers/i2c/i2c-core-acpi.c
> @@ -220,7 +220,7 @@ int i2c_acpi_get_irq(struct i2c_client *client,
> bool *wake_capable)
>         if (irq_ctx.irq == -ENOENT)
>                 irq_ctx.irq = acpi_dev_gpio_irq_wake_get(adev, 0,
> &irq_ctx.wake_capable);
> 
> -       if (wake_capable)
> +       if (irq_ctx.irq > 0 && wake_capable)
>                 *wake_capable = irq_ctx.wake_capable;
> 
>         return irq_ctx.irq;

While it's working solution it is not so flexible since basically any addition
of a new code will require if (irq > 0), that's why I'm in favour of my
proposal rather than yours approach.


-- 
With Best Regards,
Andy Shevchenko