Re: [PATCH v3] gpio: pca953x: Override IRQ for one of the expanders on Galileo Gen 2

[Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>]

On Wed, May 27, 2020 at 07:46:55AM +0200, Linus Walleij wrote:
> On Tue, May 26, 2020 at 7:12 PM Andy Shevchenko
> <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
> 
> > +static int pca953x_acpi_get_irq(struct device *dev)
> > +{
> > +       int pin, ret;
> > +
> > +       pin = pca953x_acpi_find_pin(dev);
> > +       if (pin < 0)
> > +               return pin;
> > +
> > +       dev_info(dev, "Applying ACPI interrupt quirk (GPIO %d)\n", pin);
> > +
> > +       if (!gpio_is_valid(pin))
> > +               return -EINVAL;
> > +
> > +       ret = gpio_request(pin, "pca953x interrupt");
> > +       if (ret)
> > +               return ret;
> 
> So would it work to do
> gpiochip_request_own_desc() here in some form?

It would but it will be wrong. We don't request own pin, we request pin from
upper GPIO (IRQ) chip.

> I.e. can you figure out the hardware offset number?

That's what this quirk basically does, it takes it from ACPI.

-- 
With Best Regards,
Andy Shevchenko