Implementing a gpio based regulator with status pins

[Guenter Roeck <linux@roeck-us.net>]

Hi all,

I have a system with a gpio based regulator which does not only have an
enable pin, but also a status pin to report the actual power status.
In some cases there may be a secondary status pin, making it possible
to report on/off/error.

Some twist of this is that power activation time is not exactly well
defined; activation can vary from board to board. I could of course
use the existing (fixed) timeout supported by the regulator core,
but it would be nice to be able to use an interrupt on the status
pin(s), possibly with a timeout, to achieve a dynamic activation
time.

The gpio pin(s) support interrupts, making it possible to report
status updates, which might be useful if the power source goes bad
or to support a dynamic power enable time.

As far as I can see, the existing gpio regulators don't implement
status pins.

What would be the best way to implement this ?

- Add status support to the 'fixed' regulator
- Add status support to gpio-regulator.c
- Add (gpio) status support to the regulator core
- Write a new regulator driver
- Something else

Thanks,
Guenter