RE: [PATCH] Input: elants_i2c - support palm detection

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

> -----Original Message-----
> From: Peter Hutterer [mailto:peter.hutterer@who-t.net]
> Sent: Sunday, March 29, 2020 10:15 AM
> To: Johnny Chuang
> Cc: Dmitry Torokhov; Benjamin Tissoires; linux-kernel@vger.kernel.org;
> linux-input@vger.kernel.org; Rob Schonberger; Johnny Chuang; James Chen;
> Jennifer Tsai; Paul Liang; Jeff Chuang
> Subject: Re: [PATCH] Input: elants_i2c - support palm detection
> 
> On Thu, Mar 26, 2020 at 03:58:45PM +0800, Johnny Chuang wrote:
> > From: Johnny Chuang <johnny.chuang@emc.com.tw>
> >
> > Elan define finger/palm detection on the least significant bit of byte
33.
> > The default value is 1 for all firmwares, which report as
MT_TOOL_FINGER.
> > If firmware support palm detection, the bit will change to 0 and
> > report as MT_TOOL_PALM when firmware detecting palm.
> >
> > Signed-off-by: Johnny Chuang <johnny.chuang@emc.com.tw>
> > ---
> >  drivers/input/touchscreen/elants_i2c.c | 11 ++++++++++-
> >  1 file changed, 10 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/input/touchscreen/elants_i2c.c
> > b/drivers/input/touchscreen/elants_i2c.c
> > index 14c577c..3b4d9eb3 100644
> > --- a/drivers/input/touchscreen/elants_i2c.c
> > +++ b/drivers/input/touchscreen/elants_i2c.c
> > @@ -73,6 +73,7 @@
> >  #define FW_POS_STATE		1
> >  #define FW_POS_TOTAL		2
> >  #define FW_POS_XY		3
> > +#define FW_POS_TOOL_TYPE	33
> >  #define FW_POS_CHECKSUM		34
> >  #define FW_POS_WIDTH		35
> >  #define FW_POS_PRESSURE		45
> > @@ -842,6 +843,7 @@ static void elants_i2c_mt_event(struct elants_data
> > *ts, u8 *buf)  {
> >  	struct input_dev *input = ts->input;
> >  	unsigned int n_fingers;
> > +	unsigned int tool_type;
> >  	u16 finger_state;
> >  	int i;
> >
> > @@ -852,6 +854,12 @@ static void elants_i2c_mt_event(struct elants_data
> *ts, u8 *buf)
> >  	dev_dbg(&ts->client->dev,
> >  		"n_fingers: %u, state: %04x\n",  n_fingers, finger_state);
> >
> > +	/* Note: all fingers have the same tool type */
> > +	if (buf[FW_POS_TOOL_TYPE] & 0x01)
> > +		tool_type = MT_TOOL_FINGER;
> > +	else
> > +		tool_type = MT_TOOL_PALM;
> > +
> >  	for (i = 0; i < MAX_CONTACT_NUM && n_fingers; i++) {
> >  		if (finger_state & 1) {
> >  			unsigned int x, y, p, w;
> > @@ -867,7 +875,7 @@ static void elants_i2c_mt_event(struct elants_data
> *ts, u8 *buf)
> >  				i, x, y, p, w);
> >
> >  			input_mt_slot(input, i);
> > -			input_mt_report_slot_state(input, MT_TOOL_FINGER,
true);
> > +			input_mt_report_slot_state(input, tool_type, true);
> >  			input_event(input, EV_ABS, ABS_MT_POSITION_X, x);
> >  			input_event(input, EV_ABS, ABS_MT_POSITION_Y, y);
> >  			input_event(input, EV_ABS, ABS_MT_PRESSURE, p); @@
> -1307,6 +1315,7
> > @@ static int elants_i2c_probe(struct i2c_client *client,
> >  	input_set_abs_params(ts->input, ABS_MT_POSITION_Y, 0, ts->y_max, 0,
> 0);
> >  	input_set_abs_params(ts->input, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);
> >  	input_set_abs_params(ts->input, ABS_MT_PRESSURE, 0, 255, 0, 0);
> > +	input_set_abs_params(ts->input, ABS_MT_TOOL_TYPE, 0,
> MT_TOOL_MAX, 0,
> > +0);
> 
> if you're only reporting pen and palm, can we set this to MT_TOOL_PALM
> instead? Otherwise you're indicating you may also send MT_TOOL_DIAL which
> is unlikely on this hardware :)
> 

Yes, we do not have MT_TOOL_DIAL on touch screen.
So I need to modify MT_TOOL_MAX to MT_TOOL_PALM, right?

> Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net> otherwise
> 
> Cheers,
>    Peter
> 
> >  	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);
> > --
> > 2.7.4
> >