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

[Peter Hutterer <peter.hutterer@who-t.net>]

On Mon, Mar 30, 2020 at 08:59:51AM +0800, Johnny.Chuang wrote:
> > -----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?

yes please.

Cheers,
   Peter

> 
> > 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
> > >
>