Input: ALPS - clean up code for SS5 hardware

The return value of alps_get_pkt_id_ss4_v2() should really be "enum
SS4_PACKET_ID", not "unsigned char".  Correct this.

Also, most of the Alps SS5 (SS4 v2) packet byte parsing code is implemented
using macros, but there are a few places where bytes are directly
manipulated in alps.c.  For consistency, migrate the rest of these to
macros.
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Paul Donohue <linux-kernel@PaulSD.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/mouse/alps.c

@@ -1153,15 +1153,13 @@ static void alps_process_packet_v7(struct psmouse *psmouse)
 		alps_process_touchpad_packet_v7(psmouse);
 }
 
-static unsigned char alps_get_pkt_id_ss4_v2(unsigned char *byte)
+static enum SS4_PACKET_ID alps_get_pkt_id_ss4_v2(unsigned char *byte)
 {
-	unsigned char pkt_id = SS4_PACKET_ID_IDLE;
+	enum SS4_PACKET_ID pkt_id = SS4_PACKET_ID_IDLE;
 
 	switch (byte[3] & 0x30) {
 	case 0x00:
-		if (byte[0] == 0x18 && byte[1] == 0x10 && byte[2] == 0x00 &&
-		    (byte[3] & 0x88) == 0x08 && byte[4] == 0x10 &&
-		    byte[5] == 0x00) {
+		if (SS4_IS_IDLE_V2(byte)) {
 			pkt_id = SS4_PACKET_ID_IDLE;
 		} else {
 			pkt_id = SS4_PACKET_ID_ONE;
@@ -1188,7 +1186,7 @@ static int alps_decode_ss4_v2(struct alps_fields *f,
 			      unsigned char *p, struct psmouse *psmouse)
 {
 	struct alps_data *priv = psmouse->private;
-	unsigned char pkt_id;
+	enum SS4_PACKET_ID pkt_id;
 	unsigned int no_data_x, no_data_y;
 
 	pkt_id = alps_get_pkt_id_ss4_v2(p);
@@ -1306,7 +1304,6 @@ static void alps_process_packet_ss4_v2(struct psmouse *psmouse)
 	struct input_dev *dev = psmouse->dev;
 	struct input_dev *dev2 = priv->dev2;
 	struct alps_fields *f = &priv->f;
-	int x, y, pressure;
 
 	memset(f, 0, sizeof(struct alps_fields));
 	priv->decode_fields(f, packet, psmouse);
@@ -1349,13 +1346,9 @@ static void alps_process_packet_ss4_v2(struct psmouse *psmouse)
 			return;
 		}
 
-		x = (s8)(((packet[0] & 1) << 7) | (packet[1] & 0x7f));
-		y = (s8)(((packet[3] & 1) << 7) | (packet[2] & 0x7f));
-		pressure = (s8)(packet[4] & 0x7f);
-
-		input_report_rel(dev2, REL_X, x);
-		input_report_rel(dev2, REL_Y, -y);
-		input_report_abs(dev2, ABS_PRESSURE, pressure);
+		input_report_rel(dev2, REL_X, SS4_TS_X_V2(packet));
+		input_report_rel(dev2, REL_Y, SS4_TS_Y_V2(packet));
+		input_report_abs(dev2, ABS_PRESSURE, SS4_TS_Z_V2(packet));
 
 		input_report_key(dev2, BTN_LEFT, f->ts_left);
 		input_report_key(dev2, BTN_RIGHT, f->ts_right);

drivers/input/mouse/alps.h

@@ -54,7 +54,15 @@ enum SS4_PACKET_ID {
 
 #define SS4_MASK_NORMAL_BUTTONS		0x07
 
-#define SS4_1F_X_V2(_b)		((_b[0] & 0x0007) |		\
+#define SS4_IS_IDLE_V2(_b)	(((_b[0]) == 0x18) &&		\
+				 ((_b[1]) == 0x10) &&		\
+				 ((_b[2]) == 0x00) &&		\
+				 ((_b[3] & 0x88) == 0x08) &&	\
+				 ((_b[4]) == 0x10) &&		\
+				 ((_b[5]) == 0x00)		\
+				)
+
+#define SS4_1F_X_V2(_b)		(((_b[0]) & 0x0007) |		\
 				 ((_b[1] << 3) & 0x0078) |	\
 				 ((_b[1] << 2) & 0x0380) |	\
 				 ((_b[2] << 5) & 0x1C00)	\
@@ -101,6 +109,18 @@ enum SS4_PACKET_ID {
 #define SS4_IS_MF_CONTINUE(_b)	((_b[2] & 0x10) == 0x10)
 #define SS4_IS_5F_DETECTED(_b)	((_b[2] & 0x10) == 0x10)
 
+#define SS4_TS_X_V2(_b)		(s8)(				\
+				 ((_b[0] & 0x01) << 7) |	\
+				 (_b[1] & 0x7F)		\
+				)
+
+#define SS4_TS_Y_V2(_b)		(s8)(				\
+				 ((_b[3] & 0x01) << 7) |	\
+				 (_b[2] & 0x7F)		\
+				)
+
+#define SS4_TS_Z_V2(_b)		(s8)(_b[4] & 0x7F)
+
 
 #define SS4_MFPACKET_NO_AX	8160	/* X-Coordinate value */
 #define SS4_MFPACKET_NO_AY	4080	/* Y-Coordinate value */