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

From: Peter Hutterer
Date: Sat Mar 28 2020 - 22:15:03 EST


On Thu, Mar 26, 2020 at 03:58:45PM +0800, Johnny Chuang wrote:
> From: Johnny Chuang <johnny.chuang@xxxxxxxxxx>
>
> 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@xxxxxxxxxx>
> ---
> 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@xxxxxxxxx> 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
>