Hello Andy,

quoted

From: Alexander Sverdlin <redacted>

There are several implementations of PL061 which lack GPIOINTR signal in
hardware and only have individual GPIOMIS[7:0] interrupts. Use the
hierarchical interrupt support of the gpiolib in these cases (if at least 8
IRQs are configured for the PL061).

One in-tree example is arch/arm/boot/dts/axm55xx.dtsi, PL061 instances have
8 IRQs defined, but current driver supports only the first one, so only one
pin would work as IRQ trigger.

an IRQ

I'm wondering if the GPIO library support for IRQ hierarchy is what
you are looking for.

do you have a better suggestion? That's why I reference the below discussion from 2017, where 
Linus Walleij suggested to use it. Well, the initial patch was just 11-liner and PL061 is
rather counterexample and doesn't fit well into the existing hierarchical infrastructure. 

quoted

Link: https://lore.kernel.org/linux-gpio/CACRpkdZpYzpMDWqJobSYH=JHgB74HbCQihOtexs+sVyo6SRJdA@mail.gmail.com/ (local)

[...]

quoted

--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig

@@ -469,6 +469,7 @@ config GPIO_PL061
        depends on ARM_AMBA
        select IRQ_DOMAIN
        select GPIOLIB_IRQCHIP
+       select IRQ_DOMAIN_HIERARCHY

-- 
Best regards,
Alexander Sverdlin.