Hi Stephen,

> There were some comments about adding an 'optional' platform_get_irq()
> API in v4. This series doesn't include that, but I can add such an API
> if it's required. I started to look into how it might work and got hung
> up on what an optional IRQ means. I suppose it means that in DT there
> isn't an 'interrupts' property in the device node, but in ACPI based
> firmware I'm not sure what that would correspond to. Furthermore, the
> return value is hard to comprehend. Do we return an error when an
> optional irq can't be found? It doesn't seem safe to return 0 because
> sometimes 0 is a valid IRQ. Do other errors in parsing the IRQ
> constitute a failure when the IRQ is optional?

Some time ago, I tried a series like yours and got stuck at this very
point. I found drivers where using an interrupt was optional and
platform_get_irq() returning a failure wasn't fatal. The drivers used
PIO then or dropped some additional functionality. Some of them were
very old.

I didn't like the idea that platform_get_irq() will spit out errors for
those drivers, yet I couldn't create a suitable cocci-script to convert
drivers to use the *_optional callback where possible. So, I neither
created the optional callback.

I still have doubts of unneeded error messages popping up. Has this been
discussed already? (Sorry, I missed the first iterations of this series)

Thanks,

   Wolfram