[PATCH 2/2] Input: Adding DT support for keyreset tuneables

[Grant Likely]

On Wed, Jul 10, 2013 at 5:52 PM, Dmitry Torokhov
<dmitry.torokhov at gmail.com> wrote:
> On Wed, Jul 10, 2013 at 04:14:57PM +0100, Grant Likely wrote:
>> On Fri, 28 Jun 2013 07:19:06 -0600, Mathieu Poirier <mathieu.poirier at linaro.org> wrote:
>> > On 13-06-28 12:09 AM, Dmitry Torokhov wrote:
>> > >>>> I do not agree.  We want the binding to be generic and not tied
>> > >>>> specifically to the keyreset functionality.  As such 'input-keyset' or
>> > >>>> 'input-keychord' are more appropriate.
>> > >>>
>> > >>> The binding is defined specifically for sysrq and specifically to
>> > >>> perform reset action.
>> > >>
>> > >> Yes for now but as the examples in the binding show, it is easy to
>> > >> envision how other drivers could use it.
>> > >
>> > > I think you over-complicate things here. Unlike matrix-keypad binding,
>> > > where you have a common parsing code, here we have an individual driver.
>> > > I really do not see anyone else using such sequences or chords as such
>> > > processing should be done in userspace. Sysrq is quite an exception.
>> >
>> > To be honest I don't have a very strong opinion on the binding.  I made
>> > it as generic as possible on the guidance of the DT people.  Let's see
>> > what they think of it.
>>
>> Hi Mathieu,
>>
>> As per our conversation just now at Connect, the binding should probably
>> look like this:
>>
>> Sysrq keyset binding:
>>
>> The /chosen node can contain a linux,input-keyset-sysrq child node to
>> define a set of keys that will generate a sysrq when pressed together.
>
> Hmm, we would have only one such node, /sysrq, or /linux,sysrq,
> whatever. The sysrq setting is system-wide and applicable to all
> devices. Given that it is used only on mobile, where there not that
> many input devices (a few keys and touchscreen) I do not believe we
> should consider adding per-device settings.

It's in /chosen, that isn't per-device.

>> Required properties:
>> keyset: array of keycodes
>
> Please, let's call it 'key-reset-seq', because it is exactly the reset
> sequence. There won't be any additional sequences or chords as those
> should be handled in userspace, sysrq is a special case here.

This is absolutely a linux-specific binding. It encodes the Linux
keycodes, and generates a linux meaning. I'm usually all about
carrying the OS-independent banner when defining DT bindings, but in
this case the linux prefix and sysrq reference is completely
appropriate.

g.