Re: [PATCH] Input: wm97xx: add BTN_TOUCH event to wm97xx to use it with Android

[Mike Rapoport <mike@compulab.co.il>]

Mark Brown wrote:
> On Tue, Feb 17, 2009 at 01:42:19PM +0200, Mike Rapoport wrote:
> 
>> The difficulty here is to find out when BTN_TOUCH should be generated and what
>> should be its value. As far as I can see from different drivers, there's no
>> one-to-one correspondence between ABS_PRESSURE and BTN_TOUCH. For instance,
>> drivers/input/mouse/synaptics.c has
> 
> As a default it should be fine to check for zero/non-zero.  Anything
> that wants to override the behaviour could supply their own BTN_TOUCH.
> Another option would be to change Android user space to support pressure
> only touchscreens.

Android uses test_bit(BTN_TOUCH) to detect a touchscreen. So, adding generated
BTN_TOUCH event in the input core without changing the input_dev->keybit won't
help. And if we force BTN_TOUCH set in the input core there would be no way to
differentiate between devices that supply their own BTN_TOUCH and devices that
don't.
Apparently the most correct way would be to change Android touchscreen detection
and BTN_TOUCH/ABS_PRESSURE handling. But until it's done I'd prefer wm97xx to
report BTN_TOUCH :)

> Like I say, I'm fine with the patch itself so it's got my ack - it just
> feels like it fixes the problem at the wrong level.   From that PoV
> consider it to have
> 
> Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
> 

-- 
Sincerely yours,
Mike.