Re: [PATCH 3/3] gpio: regmap: Support a custom ->to_irq() hook

[Aidan MacDonald <aidanmacdonald.0x0@xxxxxxxxx>]

Andy Shevchenko <andy.shevchenko@xxxxxxxxx> writes:

> On Tue, Jul 5, 2022 at 1:22 PM Aidan MacDonald
> <aidanmacdonald.0x0@xxxxxxxxx> wrote:
>
> ...
>
>> Is that really better than simply using ->to_irq()?
>
> We have Intel PMIC drivers (that are in MFD) and they have respective
> GPIO drivers, none of them is using ->to_irq() and all of them provide
> IRQ functionality. Can it be taken as an example or is it something
> quite different to your hardware?

In the Intel PMICs the MFD irqchip has a single interrupt for all GPIOs.
The GPIO driver then has its own irqchip and it looks at other registers
to find out which GPIO interrupt fired. It's a typical cascaded setup.

In my case the MFD irqchip has one interrupt per GPIO. The GPIO driver
does not need its own irqchip; everything is handled by the MFD irqchip.
Existing examples include wm831x, wm8994, da9052, and tps6586x.