HID: wacom: report distance for Intuos4 WL

This patch adds reporting of distance of tool to the tablet surface. Maximum
reported value is 63 (0x3F).

Signed-off-by: Przemo Firszt <przemo@firszt.eu>
Acked-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-wacom.c

@@ -320,6 +320,7 @@ static void wacom_i4_parse_pen_report(struct wacom_data *wdata,
 			struct input_dev *input, unsigned char *data)
 {
 	__u16 x, y, pressure;
+	__u8 distance;
 
 	switch (data[1]) {
 	case 0x80: /* Out of proximity report */
@@ -353,6 +354,7 @@ static void wacom_i4_parse_pen_report(struct wacom_data *wdata,
 		y = data[4] << 9 | data[5] << 1 | (data[9] & 0x01);
 		pressure = (data[6] << 3) | ((data[7] & 0xC0) >> 5)
 			| (data[1] & 0x01);
+		distance = (data[9] >> 2) & 0x3f;
 
 		input_report_key(input, BTN_TOUCH, pressure > 1);
 
@@ -362,6 +364,7 @@ static void wacom_i4_parse_pen_report(struct wacom_data *wdata,
 		input_report_abs(input, ABS_X, x);
 		input_report_abs(input, ABS_Y, y);
 		input_report_abs(input, ABS_PRESSURE, pressure);
+		input_report_abs(input, ABS_DISTANCE, distance);
 		input_report_abs(input, ABS_MISC, wdata->id);
 		input_event(input, EV_MSC, MSC_SERIAL, wdata->serial);
 		input_report_key(input, wdata->tool, 1);
@@ -484,6 +487,7 @@ static int wacom_input_mapped(struct hid_device *hdev, struct hid_input *hi,
 		input_set_abs_params(input, ABS_X, 0, 40640, 4, 0);
 		input_set_abs_params(input, ABS_Y, 0, 25400, 4, 0);
 		input_set_abs_params(input, ABS_PRESSURE, 0, 2047, 0, 0);
+		input_set_abs_params(input, ABS_DISTANCE, 0, 63, 0, 0);
 		break;
 	}