Input: elantech - correct x, y value range for v2 hardware

x, y values are actually 12-bit long. Also update protocol document to
reflect the change.

Signed-off-by: JJ Ding <jj_ding@emc.com.tw>
Acked-by: Daniel Kurtz <djkurtz@chromium.org>
Acked-by: Éric Piel <eric.piel@tremplin-utc.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

Documentation/input/elantech.txt

@@ -389,14 +389,14 @@ byte 0:
 byte 1:
 
    bit   7   6   5   4   3   2   1   0
-	 p7  p6  p5  p4  .  x10 x9  x8
+	 p7  p6  p5  p4 x11 x10 x9  x8
 
 byte 2:
 
    bit   7   6   5   4   3   2   1   0
 	 x7  x6  x5  x4  x3  x2  x1  x0
 
-         x10..x0 = absolute x value (horizontal)
+         x11..x0 = absolute x value (horizontal)
 
 byte 3:
 
@@ -420,7 +420,7 @@ byte 3:
 byte 4:
 
    bit   7   6   5   4   3   2   1   0
-        p3  p1  p2  p0   .   .  y9  y8
+        p3  p1  p2  p0  y11 y10 y9  y8
 
 	 p7..p0 = pressure (not EF113)
 
@@ -429,7 +429,7 @@ byte 5:
    bit   7   6   5   4   3   2   1   0
         y7  y6  y5  y4  y3  y2  y1  y0
 
-         y9..y0 = absolute y value (vertical)
+         y11..y0 = absolute y value (vertical)
 
 
 4.2.2 Two finger touch

drivers/input/mouse/elantech.c

@@ -290,15 +290,15 @@ static void elantech_report_absolute_v2(struct psmouse *psmouse)
 		/* pass through... */
 	case 1:
 		/*
-		 * byte 1:  .   .   .   .   .  x10 x9  x8
+		 * byte 1:  .   .   .   .  x11 x10 x9  x8
 		 * byte 2: x7  x6  x5  x4  x4  x2  x1  x0
 		 */
-		x1 = ((packet[1] & 0x07) << 8) | packet[2];
+		x1 = ((packet[1] & 0x0f) << 8) | packet[2];
 		/*
-		 * byte 4:  .   .   .   .   .   .  y9  y8
+		 * byte 4:  .   .   .   .  y11 y10 y9  y8
 		 * byte 5: y7  y6  y5  y4  y3  y2  y1  y0
 		 */
-		y1 = ETP_YMAX_V2 - (((packet[4] & 0x03) << 8) | packet[5]);
+		y1 = ETP_YMAX_V2 - (((packet[4] & 0x0f) << 8) | packet[5]);
 
 		input_report_abs(dev, ABS_X, x1);
 		input_report_abs(dev, ABS_Y, y1);