Re: [PATCH v3 1/3] dt-bindings: gpio: spacemit: add support for K1 SoC

[Linus Walleij]

On Wed, Dec 25, 2024 at 1:33 AM Yixun Lan <dlan@xxxxxxxxxx> wrote:

> The GPIO controller of K1 support basic functions as input/output,
> all pins can be used as interrupt which route to one IRQ line,
> trigger type can be select between rising edge, failing edge, or both.
> There are four GPIO banks, each consisting of 32 pins.
(...)
> +description:
> +  The controller's registers are organized as sets of eight 32-bit
> +  registers with each set controlling a bank of up to 32 pins.  A single
> +  interrupt is shared for all of the banks handled by the controller.

I looked at the driver and came to the conclusion that it's better to use
4 different instances of the chip, one for each set of 32bit registers,
so these 4 GPIO controllers are instantiated separately.

The operating system can handle the shared interrupt, there is no
need to use a single device instance just because the interrupt is
shared.

DT bindings are operating system neutral, but for example in Linux
(if we pretend this is just one possible example) then a driver
handling a shared IRQ can be requested with the flag IRQF_SHARED
and the driver can just return IRQ_HANDLED if it handled an IRQ
or IRQ_NONE if it didn't handle the irq (so other instances can
handle it).

Yours,
Linus Walleij