Input: elantech - add special check for fw_version 0x470f01 touchpad

It is no need to check the packet[0] for sanity check when doing
elantech_packet_check_v4() function for fw_version = 0x470f01 touchpad.

Signed-off by: Duson Lin <dusonlin@emc.com.tw>
Reviewed-by: Ulrik De Bie <ulrik.debie-os@e2big.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/mouse/elantech.c

@@ -783,19 +783,26 @@ 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;
+	unsigned int ic_version;
 	bool sanity_check;
 
 	if (etd->tp_dev && (packet[3] & 0x0f) == 0x06)
 		return PACKET_TRACKPOINT;
 
+	/* This represents the version of IC body. */
+	ic_version = (etd->fw_version & 0x0f0000) >> 16;
+
 	/*
 	 * 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.
+	 * the hardware flag 'crc_enabled' and the version of
+	 * the IC body, but are the same for every packet,
+	 * regardless of the type.
 	 */
 	if (etd->crc_enabled)
 		sanity_check = ((packet[3] & 0x08) == 0x00);
+	else if (ic_version == 7 && etd->samples[1] == 0x2A)
+		sanity_check = ((packet[3] & 0x1c) == 0x10);
 	else
 		sanity_check = ((packet[0] & 0x0c) == 0x04 &&
 				(packet[3] & 0x1c) == 0x10);
@@ -1116,6 +1123,7 @@ static int elantech_get_resolution_v4(struct psmouse *psmouse,
  * Avatar AVIU-145A2       0x361f00        ?               clickpad
  * Fujitsu LIFEBOOK E544   0x470f00        d0, 12, 09      2 hw buttons
  * Fujitsu LIFEBOOK E554   0x570f01        40, 14, 0c      2 hw buttons
+ * Fujitsu T725            0x470f01        05, 12, 09      2 hw buttons
  * Fujitsu H730            0x570f00        c0, 14, 0c      3 hw buttons (**)
  * Gigabyte U2442          0x450f01        58, 17, 0c      2 hw buttons
  * Lenovo L430             0x350f02        b9, 15, 0c      2 hw buttons (*)
@@ -1651,6 +1659,16 @@ int elantech_init(struct psmouse *psmouse)
 		     etd->capabilities[0], etd->capabilities[1],
 		     etd->capabilities[2]);
 
+	if (etd->hw_version != 1) {
+		if (etd->send_cmd(psmouse, ETP_SAMPLE_QUERY, etd->samples)) {
+			psmouse_err(psmouse, "failed to query sample data\n");
+			goto init_fail;
+		}
+		psmouse_info(psmouse,
+			     "Elan sample query result %02x, %02x, %02x\n",
+			     etd->samples[0], etd->samples[1], etd->samples[2]);
+	}
+
 	if (elantech_set_absolute_mode(psmouse)) {
 		psmouse_err(psmouse,
 			    "failed to put touchpad into absolute mode.\n");

drivers/input/mouse/elantech.h

@@ -129,6 +129,7 @@ struct elantech_data {
 	unsigned char reg_26;
 	unsigned char debug;
 	unsigned char capabilities[3];
+	unsigned char samples[3];
 	bool paritycheck;
 	bool jumpy_cursor;
 	bool reports_pressure;