On Mon, Jan 2, 2017 at 9:31 AM, Peter Rosin <peda@xxxxxxxxxx> wrote: > On 2016-12-30 08:49, Linus Walleij wrote: >> On Wed, Dec 14, 2016 at 6:41 PM, Peter Rosin <peda@xxxxxxxxxx> wrote: >>> On 2016-12-14 18:01, Sebastian Reichel wrote: >>>> [of course I forgot to actually add gpio people, let's try again] >>>> >>>> On Wed, Dec 14, 2016 at 05:59:21PM +0100, Sebastian Reichel wrote: >>>>> Hi, >>>>> >>>>> On Wed, Dec 14, 2016 at 12:56:45AM +0100, Peter Rosin wrote: >>>>>> If several parallel bq24735 chargers have their ac-detect gpios wired >>>>>> together (or if only one of the parallel bq24735 chargers have its >>>>>> ac-detect pin wired to a gpio, and the others are assumed to react the >>>>>> same), then all driver instances need to check the same gpio. But the >>>>>> gpio subsystem does not allow sharing gpios, so handle that locally. >>>>> >>>>> Adding GPIO subsystem people to see if they can come up with >>>>> something in the gpiod API for this usecase. >>> >>> Right, I don't like how my new code steps away from gpio descriptors. >> >> The issue of shared gpiods have come up over and over again. >> For example the messy regulator code needs this too. >> >> It is better if we implement something like gpiod_get_shared() >> in the gpiolib of these cases. >> >> Just put a refcount in struct gpio_desc in drivers/gpio/gpiolib.h >> for this case I guess? > > I actually tried that, but ran into atomicy issues with the > FLAG_REQUESTED bit and gave up. Didn't really try all that hard > though, but I simply didn't feel comfortable with going near such > fundamental designs... Oh I see. Well if it is of any help that would make me nervous too. I would just remove the use of FLAG_REQUESTED altogether, redefine the flags in gpiolib.h from 0 and add a struct kref into the struct to deal with the refcounting. That should do it. I think. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
