Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input

Pull input layer updates from Dmitry Torokhov:
 "Just a couple of new IDs in Wacom and xpad drivers, i8042 is now
  disabled on ARC, and data checks in Elantech driver that were overly
  relaxed by the previous patch are now tightened"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: i8042 - disable the driver on ARC platforms
  Input: xpad - add signature for Razer Onza Classic Edition
  Input: elantech - fix packet check for v3 and v4 hardware
  Input: wacom - add support for 0x300 and 0x301

1 files changed, 40 insertions, 4 deletions

diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
index 57b2637e153a..8551dcaf24db 100644
--- a/drivers/input/mouse/elantech.c
+++ b/drivers/input/mouse/elantech.c
@@ -672,6 +672,7 @@ static int elantech_packet_check_v2(struct psmouse *psmouse)
  */
 static int elantech_packet_check_v3(struct psmouse *psmouse)
 {
+	struct elantech_data *etd = psmouse->private;
 	const u8 debounce_packet[] = { 0xc4, 0xff, 0xff, 0x02, 0xff, 0xff };
 	unsigned char *packet = psmouse->packet;
 
@@ -682,19 +683,48 @@ static int elantech_packet_check_v3(struct psmouse *psmouse)
 	if (!memcmp(packet, debounce_packet, sizeof(debounce_packet)))
 		return PACKET_DEBOUNCE;
 
-	if ((packet[0] & 0x0c) == 0x04 && (packet[3] & 0xcf) == 0x02)
-		return PACKET_V3_HEAD;
+	/*
+	 * If the hardware flag 'crc_enabled' is set the packets have
+	 * different signatures.
+	 */
+	if (etd->crc_enabled) {
+		if ((packet[3] & 0x09) == 0x08)
+			return PACKET_V3_HEAD;
+
+		if ((packet[3] & 0x09) == 0x09)
+			return PACKET_V3_TAIL;
+	} else {
+		if ((packet[0] & 0x0c) == 0x04 && (packet[3] & 0xcf) == 0x02)
+			return PACKET_V3_HEAD;
 
-	if ((packet[0] & 0x0c) == 0x0c && (packet[3] & 0xce) == 0x0c)
-		return PACKET_V3_TAIL;
+		if ((packet[0] & 0x0c) == 0x0c && (packet[3] & 0xce) == 0x0c)
+			return PACKET_V3_TAIL;
+	}
 
 	return PACKET_UNKNOWN;
 }
 
 static int elantech_packet_check_v4(struct psmouse *psmouse)
 {
+	struct elantech_data *etd = psmouse->private;
 	unsigned char *packet = psmouse->packet;
 	unsigned char packet_type = packet[3] & 0x03;
+	bool sanity_check;
+
+	/*
+	 * Sanity check based on the constant bits of a packet.
+	 * The constant bits change depending on the value of
+	 * the hardware flag 'crc_enabled' but are the same for
+	 * every packet, regardless of the type.
+	 */
+	if (etd->crc_enabled)
+		sanity_check = ((packet[3] & 0x08) == 0x00);
+	else
+		sanity_check = ((packet[0] & 0x0c) == 0x04 &&
+				(packet[3] & 0x1c) == 0x10);
+
+	if (!sanity_check)
+		return PACKET_UNKNOWN;
 
 	switch (packet_type) {
 	case 0:
@@ -1313,6 +1343,12 @@ static int elantech_set_properties(struct elantech_data *etd)
 			etd->reports_pressure = true;
 	}
 
+	/*
+	 * The signatures of v3 and v4 packets change depending on the
+	 * value of this hardware flag.
+	 */
+	etd->crc_enabled = ((etd->fw_version & 0x4000) == 0x4000);
+
 	return 0;
 }