diff --git a/drivers/input/mouse/focaltech.c b/drivers/input/mouse/focaltech.c
index 6fd5fff0cbff..23e387c5afd8 100644
--- a/drivers/input/mouse/focaltech.c
+++ b/drivers/input/mouse/focaltech.c
@@ -202,8 +202,8 @@ static void focaltech_process_rel_packet(struct psmouse *psmouse,
 	state->pressed = packet[0] >> 7;
 	finger1 = ((packet[0] >> 4) & 0x7) - 1;
 	if (finger1 < FOC_MAX_FINGERS) {
-		state->fingers[finger1].x += (char)packet[1];
-		state->fingers[finger1].y += (char)packet[2];
+		state->fingers[finger1].x += (signed char)packet[1];
+		state->fingers[finger1].y += (signed char)packet[2];
 	} else {
 		psmouse_err(psmouse, "First finger in rel packet invalid: %d\n",
 			    finger1);
@@ -218,8 +218,8 @@ static void focaltech_process_rel_packet(struct psmouse *psmouse,
 	 */
 	finger2 = ((packet[3] >> 4) & 0x7) - 1;
 	if (finger2 < FOC_MAX_FINGERS) {
-		state->fingers[finger2].x += (char)packet[4];
-		state->fingers[finger2].y += (char)packet[5];
+		state->fingers[finger2].x += (signed char)packet[4];
+		state->fingers[finger2].y += (signed char)packet[5];
 	}
 }
 
@@ -374,7 +374,7 @@ static int focaltech_read_size(struct psmouse *psmouse)
 {
 	struct ps2dev *ps2dev = &psmouse->ps2dev;
 	struct focaltech_data *priv = psmouse->private;
-	char param[3];
+	signed char param[3];
 
 	if (focaltech_read_register(ps2dev, 2, param))
 		return -EIO;