Input: elants_i2c - report resolution of ABS_MT_TOUCH_MAJOR by FW information.

This patch adds a new behavior to report touch major resolution
based on information provided by firmware.

In initial process, driver acquires touch information from touch ic.
It contains one byte about the resolution value of ABS_MT_TOUCH_MAJOR.
Touch driver will report touch major resolution by this information.
Signed-off-by: Johnny Chuang <johnny.chuang.emc@gmail.com>
Reviewed-by: Harry Cutts <hcutts@chromium.org>
Link: https://lore.kernel.org/r/1598581195-9874-1-git-send-email-johnny.chuang.emc@gmail.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/elants_i2c.c

@@ -134,6 +134,7 @@ struct elants_data {
 	u8 bc_version;
 	u8 iap_version;
 	u16 hw_version;
+	u8 major_res;
 	unsigned int x_res;	/* resolution in units/mm */
 	unsigned int y_res;
 	unsigned int x_max;
@@ -459,6 +460,9 @@ static int elants_i2c_query_ts_info(struct elants_data *ts)
 	rows = resp[2] + resp[6] + resp[10];
 	cols = resp[3] + resp[7] + resp[11];
 
+	/* Get report resolution value of ABS_MT_TOUCH_MAJOR */
+	ts->major_res = resp[16];
+
 	/* Process mm_to_pixel information */
 	error = elants_i2c_execute_command(client,
 					   get_osr_cmd, sizeof(get_osr_cmd),
@@ -1325,6 +1329,8 @@ static int elants_i2c_probe(struct i2c_client *client,
 			     0, MT_TOOL_PALM, 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);
+	if (ts->major_res > 0)
+		input_abs_set_res(ts->input, ABS_MT_TOUCH_MAJOR, ts->major_res);
 
 	touchscreen_parse_properties(ts->input, true, &ts->prop);