[PATCH] gpio/mxs: support irqs triggered by both edges

[enrico.scholz@sigma-chemnitz.de (Enrico Scholz)]

Grant Likely <grant.likely@secretlab.ca> writes:

>> iMX28 silicon does not support irqs triggered by both gpio edges. Patch
>> emulates this behavior by configuring such irqs as level triggered and
>> by switching polarity in the interrupt handler.
>
> That looks dodgy and hacky.  This will definitely miss interrupts if
> they come in too fast. 

Because patch calculates the trigger from the actual level, there should
not be missed more interrupts than with native edge-both support.

> I don't like this approach.  What do you need it for?

some drivers (e.g. gpio-keys, otg gpio-vbus, gpio-charger) are requesting
gpio based interrupts with IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING
flags.  It is not possible to use such drivers without having EDGE_BOTH
support.


Enrico