RE: [PATCH] Input: elants_i2c - Report resolution information for touch major

["Johnny.Chuang" <johnny.chuang@emc.com.tw>]

> > -----Original Message-----
> > From: Peter Hutterer [mailto:peter.hutterer@who-t.net]
> > Sent: Friday, February 28, 2020 6:36 AM
> > To: Johnny Chuang
> > Cc: Dmitry Torokhov; Benjamin Tissoires; linux-kernel@vger.kernel.org;
> > linux-input@vger.kernel.org; Johnny Chuang; Jennifer Tsai; James Chen;
> > Paul Liang; Jeff Chuang
> > Subject: Re: [PATCH] Input: elants_i2c - Report resolution information
> > for touch major
> >
> > On Thu, Feb 27, 2020 at 09:13:20AM +0800, Johnny Chuang wrote:
> > > From: Johnny Chuang <johnny.chuang@emc.com.tw>
> > >
> > > This patch supports reporting resolution for ABS_MT_TOUCH_MAJOR
> event.
> > > This information is needed in showing pressure/width radius.
> > >
> > > Signed-off-by: Johnny Chuang <johnny.chuang@emc.com.tw>
> > > ---
> > >  drivers/input/touchscreen/elants_i2c.c | 1 +
> > >  1 file changed, 1 insertion(+)
> > >
> > > diff --git a/drivers/input/touchscreen/elants_i2c.c
> > b/drivers/input/touchscreen/elants_i2c.c
> > > index 4911799..14c577c 100644
> > > --- a/drivers/input/touchscreen/elants_i2c.c
> > > +++ b/drivers/input/touchscreen/elants_i2c.c
> > > @@ -1309,6 +1309,7 @@ static int elants_i2c_probe(struct i2c_client
> > *client,
> > >  	input_set_abs_params(ts->input, ABS_MT_PRESSURE, 0, 255, 0, 0);
> > >  	input_abs_set_res(ts->input, ABS_MT_POSITION_X, ts->x_res);
> > >  	input_abs_set_res(ts->input, ABS_MT_POSITION_Y, ts->y_res);
> > > +	input_abs_set_res(ts->input, ABS_MT_TOUCH_MAJOR, 1);
> >
> > official resolution for absinfo is "units per mm", so a value of 3
> > would mean 3mm, is that correct?
> 
> Correct.
> This resolution (1 unit/mm) is for all elan I2C touchscreen devices,
including
> the touchscreen devices in the future.
> This information is from our firmware members.

Hi Peter / Benjamin,
Could you help to review and approve this patch?

> 
> >
> > Not that it matters too much, since touch major is already all over
> > the place and needs userspace overrides for every device but it'd be
> > nice to at least make this useful out of the box on one device class.
> >
> > Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
> >
> > otherwise
> >
> > Cheers,
> >    Peter
> >
> > >
> > >  	error = input_register_device(ts->input);
> > >  	if (error) {
> > > --
> > > 2.7.4
> > >