Re: [PATCH 3/3] gpio: Add reference counting for non-exclusive GPIOs

From: Charles Keepax
Date: Mon Nov 26 2018 - 09:30:43 EST

On Mon, Nov 26, 2018 at 02:09:27PM +0000, Mark Brown wrote:
> On Mon, Nov 26, 2018 at 01:00:01PM +0000, Charles Keepax wrote:
> > On Fri, Nov 23, 2018 at 01:25:22PM +0000, Mark Brown wrote:
> > > help the multiple users find each other somehow. I think what we want
> > > to do here is either push the gpiod requests into the regulator core or
> > > change things so that once the regulator is registered with the
> > > regulator core the regulator core owns and is responsible for freeing
> > > the regulator.
> > On the co-ordinating do we expect that the behaviour will
> > be that the GPIO should in the "enabled" state whenever any
> > regulator is requesting it? IE. the GPIO state is an OR of
> > the regulator states. Or are we expecting to handle more
> > complex interaction?
> For the regulators that's what we do, yes - it's like they're all
> sharing a single regulator. That probably won't be true in general for
> all GPIO users.

Would there perhaps be milage in looking at just making
the regulator core request the GPIO, rather than the end
drivers? Gives us a single request/free point. We don't need
any special flags in the GPIO layer, as its just a single
user as far as GPIO is concerned.