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References: <20220912221317.2775651-1-rrangel@chromium.org>
 <20220912160931.v2.7.I8af4282adc72eb9f247adcd03676a43893a020a6@changeid> <YyC9N62JaMGaeanf@smile.fi.intel.com>
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From:   Raul Rangel <rrangel@chromium.org>
Date:   Tue, 13 Sep 2022 12:07:53 -0600
Message-ID: <CAHQZ30DAr_BwH03=bG9tfCSGW+-he-c-4PPeJMOqH28cVcKDoA@mail.gmail.com>
Subject: Re: [PATCH v2 07/13] i2c: acpi: Use ACPI wake capability bit to set wake_irq
To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc:     Linux ACPI <linux-acpi@vger.kernel.org>,
        linux-input <linux-input@vger.kernel.org>,
        "jingle.wu" <jingle.wu@emc.com.tw>,
        "Limonciello, Mario" <mario.limonciello@amd.com>,
        Tim Van Patten <timvp@google.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Hans de Goede <hdegoede@redhat.com>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        Wolfram Sang <wsa@kernel.org>,
        "open list:I2C SUBSYSTEM HOST DRIVERS" <linux-i2c@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
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On Tue, Sep 13, 2022 at 11:26 AM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Mon, Sep 12, 2022 at 04:13:11PM -0600, Raul E Rangel wrote:
> > Device tree already has a mechanism to pass the wake_irq. It does this
> > by looking for the wakeup-source property and setting the
> > I2C_CLIENT_WAKE flag. This CL adds the ACPI equivalent. It uses the
> > ACPI interrupt wake flag to determine if the interrupt can be used to
> > wake the system. Previously the i2c drivers had to make assumptions and
> > blindly enable the wake IRQ. This can cause spurious wake events. e.g.,
> > If there is a device with an Active Low interrupt and the device gets
> > powered off while suspending, the interrupt line will go low since it's
> > no longer powered and wakes the system. For this reason we should
> > respect the board designers wishes and honor the wake bit defined on the
> > interrupt.

>
> > +                     if (irq > 0 && acpi_wake_capable)
> > +                             client->flags |= I2C_CLIENT_WAKE;
>
> Why do we need a parameter and can't simply set this flag inside the callee?

Are you suggesting `i2c_acpi_get_irq` modify the `client->flags`? IMO
that's a little surprising since the I wouldn't expect a `get`
function to modify it's parameters. I'm fine implementing it if others
agree though.