Re: [PATCH] dt-bindings: input: Convert gpio-keys bindings to schema

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

On Thu, Jan 23, 2020 at 07:35:06PM -0600, Rob Herring wrote:
> On Thu, Jan 23, 2020 at 4:25 PM Dmitry Torokhov
> <dmitry.torokhov@gmail.com> wrote:
> >
> > Hi Rob,
> >
> > On Thu, Jan 23, 2020 at 03:42:22PM -0600, Rob Herring wrote:
> > > Convert the gpio-keys and gpio-keys-polled bindings to a DT schema. As
> > > both bindings are almost the same, combine them into a single schema.
> > >
> > > The binding said 'interrupts' was required, but testing on dts files
> > > showed that it isn't required.
> > >
> > > 'linux,input-value' was only documented for gpio-keys-polled, but there
> > > doesn't seem to be any reason for it to be specific to that.
> >
> > Actually, there is: with gpio-keys-polled we take a "snapshot" of the
> > entire device state, so we know when to generate a 0 event (the example
> > we have a device with several GPIOs with values assigned 1, 2, 3, 4, 5..
> > values, when one of the gpios is active we generate event with given
> > value, when all are inactive we generate 0 event). This does not work
> > for interrupt-only driven device.
> 
> Okay, it wasn't clear to me reading the binding doc. I'll make it conditional.

Actually, I think we can make it usable in interrupt-driver driver. For
EV_REL events we do not need to "go back to 0", and for EV_ABS, if
desired, we could allow specifying an option to scan all GPIOs
on any interrupt. This obviously will not work for pure interrupt
devices (where we do not have GPIOs).

Thanks.

-- 
Dmitry