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Date:   Sun, 29 Mar 2020 12:14:36 +1000
From:   Peter Hutterer <peter.hutterer@who-t.net>
To:     Johnny Chuang <johnny.chuang.emc@gmail.com>
Cc:     Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Benjamin Tissoires <benjamin.tissoires@redhat.com>,
        linux-kernel@vger.kernel.org, linux-input@vger.kernel.org,
        Rob Schonberger <robsc@google.com>,
        Johnny Chuang <johnny.chuang@emc.com.tw>,
        James Chen <james.chen@emc.com.tw>,
        Jennifer Tsai <jennifer.tsai@emc.com.tw>,
        Paul Liang <paul.liang@emc.com.tw>,
        Jeff Chuang <jeff.chuang@emc.com.tw>
Subject: Re: [PATCH] Input: elants_i2c - support palm detection
Message-ID: <20200329021436.GA68168@jelly>
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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 :)

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
>