Re: [PATCH v0] gpio_keys: fix gpio key driver to proper support GIC interrupt

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Thu, Jun 04, 2015 at 08:37:50PM -0700, Feng Kan wrote:
> On Thu, Jun 4, 2015 at 10:23 AM, Dmitry Torokhov
> <dmitry.torokhov@gmail.com> wrote:
> > Hi Y,
> > On Thu, Jun 04, 2015 at 02:25:12PM +0700, Y Vo wrote:
> >> GIC is designed to support two of trigger mechanisms - active level
> >> high or edge rising. But in the gpio_keys driver, it tries to use both
> >> edge rising and edge falling trigger. This patch fixes the gpio_keys
> >> driver to request only the edge rising event when failed to configure the
> >> interrupt.
> >
> > How do we get notified of button release if we only get interrupt on
> > rising edge?
> 
> On the arm gic, only the rising edge is supported. So key press can
> only be defined
> as rising edge and no key release.

Then it is not much of a key if we can't signal release.

gpio_keys
driver supports what it calls "interrupt only" mode where there is no
GPIO and we go just by the fact that we received interrupt. In this mode
the trigger type is expected to be set by the platform code (or OF), the
driver does not force need of both edges.

Thanks.

-- 
Dmitry