Re: [PATCH v2 07/13] i2c: acpi: Use ACPI wake capability bit to set wake_irq

[Raul Rangel <rrangel@chromium.org>]

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.