Problem sharing interrupts between gpioa and uart0 on Broadcom Hurricane 2 (iProc)

[Chris Packham <Chris.Packham@xxxxxxxxxxxxxxxxxxx>]

Hi,

We have a platform using the BCM53344 integrated switch/CPU. This is
part of the Hurricane 2 (technically Wolfhound) family of devices.

Currently we're using pieces of Broadcom's "iProc" SDK based on an out
of date kernel and we'd very much like to be running as close to
upstream as possible. The fact that the Ubiquiti UniFi Switch 8 is
upstream gives me some hope.

My current problem is the fact that the uart0 interrupt is shared with
the Chip Common A gpio block. When I have and interrupt node on the
gpio in the device tree I get an init exit at startup. If I remove the
interrupt node the system will boot (except I don't get cascaded
interrupts from the GPIOs).

Looking at the pinctrl-nsp-gpio.c it looks as though I might be able to
make this work if I can convince the gpio code to return IRQ_HANDLED or
IRQ_NONE but I'm struggling against the fact that the pinctrl-iproc-
gpio.c defers it's interrupt handing to the gpio core.

Is there any way I can get the gpio core to deal with the shared
interrupt?

Thanks,
Chris