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

[Raul Rangel]

On Tue, Sep 13, 2022 at 12:33 PM Andy Shevchenko
<andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
>
> On Tue, Sep 13, 2022 at 12:07:53PM -0600, Raul Rangel wrote:
> > On Tue, Sep 13, 2022 at 11:26 AM Andy Shevchenko
> > <andriy.shevchenko@xxxxxxxxxxxxxxx> 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.
>


> This is similar to what of_i2c_get_board_info() does, no?
> Note: _get_ there.
>

`*info` is an out parameter in that case. Ideally I would have
`i2c_acpi_get_irq`, `acpi_dev_gpio_irq_get_wake`,
`platform_get_irq_optional`, and `i2c_dev_irq_from_resources` all
return a `struct irq_info {int irq; bool wake_capable;}`. This would
be a larger change though.