/*

   * Elantech Touchpad driver (v6)

   *

   * Copyright (C) 2007-2009 Arjan Opmeer <arjan@opmeer.net>

   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 as published
   * by the Free Software Foundation.
   *
   * Trademarks are the property of their respective owners.
   */
  
  #include <linux/delay.h>

  #include <linux/dmi.h>

  #include <linux/slab.h>

  #include <linux/module.h>
  #include <linux/input.h>

  #include <linux/input/mt.h>

  #include <linux/serio.h>
  #include <linux/libps2.h>

  #include <asm/unaligned.h>

  #include "psmouse.h"
  #include "elantech.h"

  #define elantech_debug(fmt, ...)					\
  	do {								\
  		if (etd->debug)						\

  			psmouse_printk(KERN_DEBUG, psmouse,		\
  					fmt, ##__VA_ARGS__);		\

  	} while (0)
  
  /*
   * Send a Synaptics style sliced query command
   */
  static int synaptics_send_cmd(struct psmouse *psmouse, unsigned char c,
  				unsigned char *param)
  {
  	if (psmouse_sliced_command(psmouse, c) ||
  	    ps2_command(&psmouse->ps2dev, param, PSMOUSE_CMD_GETINFO)) {

  		psmouse_err(psmouse, "%s query 0x%02x failed.
  ", __func__, c);

  		return -1;
  	}
  
  	return 0;
  }
  
  /*

   * V3 and later support this fast command
   */
  static int elantech_send_cmd(struct psmouse *psmouse, unsigned char c,
  				unsigned char *param)
  {
  	struct ps2dev *ps2dev = &psmouse->ps2dev;
  
  	if (ps2_command(ps2dev, NULL, ETP_PS2_CUSTOM_COMMAND) ||
  	    ps2_command(ps2dev, NULL, c) ||
  	    ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO)) {
  		psmouse_err(psmouse, "%s query 0x%02x failed.
  ", __func__, c);
  		return -1;
  	}
  
  	return 0;
  }
  
  /*

   * A retrying version of ps2_command
   */
  static int elantech_ps2_command(struct psmouse *psmouse,
  				unsigned char *param, int command)
  {
  	struct ps2dev *ps2dev = &psmouse->ps2dev;
  	struct elantech_data *etd = psmouse->private;
  	int rc;
  	int tries = ETP_PS2_COMMAND_TRIES;
  
  	do {
  		rc = ps2_command(ps2dev, param, command);
  		if (rc == 0)
  			break;
  		tries--;

  		elantech_debug("retrying ps2 command 0x%02x (%d).
  ",
  				command, tries);

  		msleep(ETP_PS2_COMMAND_DELAY);
  	} while (tries > 0);
  
  	if (rc)

  		psmouse_err(psmouse, "ps2 command 0x%02x failed.
  ", command);

  
  	return rc;
  }
  
  /*
   * Send an Elantech style special command to read a value from a register
   */
  static int elantech_read_reg(struct psmouse *psmouse, unsigned char reg,
  				unsigned char *val)
  {
  	struct elantech_data *etd = psmouse->private;
  	unsigned char param[3];
  	int rc = 0;

  	if (reg < 0x07 || reg > 0x26)

  		return -1;
  
  	if (reg > 0x11 && reg < 0x20)
  		return -1;
  
  	switch (etd->hw_version) {
  	case 1:
  		if (psmouse_sliced_command(psmouse, ETP_REGISTER_READ) ||
  		    psmouse_sliced_command(psmouse, reg) ||
  		    ps2_command(&psmouse->ps2dev, param, PSMOUSE_CMD_GETINFO)) {
  			rc = -1;
  		}
  		break;
  
  	case 2:
  		if (elantech_ps2_command(psmouse,  NULL, ETP_PS2_CUSTOM_COMMAND) ||
  		    elantech_ps2_command(psmouse,  NULL, ETP_REGISTER_READ) ||
  		    elantech_ps2_command(psmouse,  NULL, ETP_PS2_CUSTOM_COMMAND) ||
  		    elantech_ps2_command(psmouse,  NULL, reg) ||
  		    elantech_ps2_command(psmouse, param, PSMOUSE_CMD_GETINFO)) {
  			rc = -1;
  		}
  		break;

  	case 3 ... 4:

  		if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
  		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
  		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
  		    elantech_ps2_command(psmouse, NULL, reg) ||
  		    elantech_ps2_command(psmouse, param, PSMOUSE_CMD_GETINFO)) {
  			rc = -1;
  		}
  		break;

  	}
  
  	if (rc)

  		psmouse_err(psmouse, "failed to read register 0x%02x.
  ", reg);

  	else if (etd->hw_version != 4)

  		*val = param[0];

  	else
  		*val = param[1];

  
  	return rc;
  }
  
  /*
   * Send an Elantech style special command to write a register with a value
   */
  static int elantech_write_reg(struct psmouse *psmouse, unsigned char reg,
  				unsigned char val)
  {
  	struct elantech_data *etd = psmouse->private;
  	int rc = 0;

  	if (reg < 0x07 || reg > 0x26)

  		return -1;
  
  	if (reg > 0x11 && reg < 0x20)
  		return -1;
  
  	switch (etd->hw_version) {
  	case 1:
  		if (psmouse_sliced_command(psmouse, ETP_REGISTER_WRITE) ||
  		    psmouse_sliced_command(psmouse, reg) ||
  		    psmouse_sliced_command(psmouse, val) ||
  		    ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_SETSCALE11)) {
  			rc = -1;
  		}
  		break;
  
  	case 2:
  		if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
  		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_WRITE) ||
  		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
  		    elantech_ps2_command(psmouse, NULL, reg) ||
  		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
  		    elantech_ps2_command(psmouse, NULL, val) ||
  		    elantech_ps2_command(psmouse, NULL, PSMOUSE_CMD_SETSCALE11)) {
  			rc = -1;
  		}
  		break;

  
  	case 3:
  		if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
  		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
  		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
  		    elantech_ps2_command(psmouse, NULL, reg) ||
  		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
  		    elantech_ps2_command(psmouse, NULL, val) ||
  		    elantech_ps2_command(psmouse, NULL, PSMOUSE_CMD_SETSCALE11)) {
  			rc = -1;
  		}
  		break;

  
  	case 4:
  		if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
  		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
  		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
  		    elantech_ps2_command(psmouse, NULL, reg) ||
  		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
  		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
  		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
  		    elantech_ps2_command(psmouse, NULL, val) ||
  		    elantech_ps2_command(psmouse, NULL, PSMOUSE_CMD_SETSCALE11)) {
  			rc = -1;
  		}
  		break;

  	}
  
  	if (rc)

  		psmouse_err(psmouse,
  			    "failed to write register 0x%02x with value 0x%02x.
  ",
  			    reg, val);

  
  	return rc;
  }
  
  /*
   * Dump a complete mouse movement packet to the syslog
   */

  static void elantech_packet_dump(struct psmouse *psmouse)

  {
  	int	i;

  	psmouse_printk(KERN_DEBUG, psmouse, "PS/2 packet [");
  	for (i = 0; i < psmouse->pktsize; i++)
  		printk("%s0x%02x ", i ? ", " : " ", psmouse->packet[i]);

  	printk("]
  ");
  }
  
  /*
   * Interpret complete data packets and report absolute mode input events for
   * hardware version 1. (4 byte packets)
   */
  static void elantech_report_absolute_v1(struct psmouse *psmouse)
  {
  	struct input_dev *dev = psmouse->dev;
  	struct elantech_data *etd = psmouse->private;
  	unsigned char *packet = psmouse->packet;
  	int fingers;

  	if (etd->fw_version < 0x020000) {

  		/*
  		 * byte 0:  D   U  p1  p2   1  p3   R   L
  		 * byte 1:  f   0  th  tw  x9  x8  y9  y8
  		 */

  		fingers = ((packet[1] & 0x80) >> 7) +
  				((packet[1] & 0x30) >> 4);
  	} else {

  		/*
  		 * byte 0: n1  n0  p2  p1   1  p3   R   L
  		 * byte 1:  0   0   0   0  x9  x8  y9  y8
  		 */

  		fingers = (packet[0] & 0xc0) >> 6;
  	}

  	if (etd->jumpy_cursor) {

  		if (fingers != 1) {
  			etd->single_finger_reports = 0;
  		} else if (etd->single_finger_reports < 2) {
  			/* Discard first 2 reports of one finger, bogus */
  			etd->single_finger_reports++;

  			elantech_debug("discarding packet
  ");

  			return;

  		}
  	}

  	input_report_key(dev, BTN_TOUCH, fingers != 0);

  	/*
  	 * byte 2: x7  x6  x5  x4  x3  x2  x1  x0
  	 * byte 3: y7  y6  y5  y4  y3  y2  y1  y0
  	 */

  	if (fingers) {
  		input_report_abs(dev, ABS_X,
  			((packet[1] & 0x0c) << 6) | packet[2]);

  		input_report_abs(dev, ABS_Y,

  			etd->y_max - (((packet[1] & 0x03) << 8) | packet[3]));

  	}
  
  	input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
  	input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
  	input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);
  	input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
  	input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);

  	if (etd->fw_version < 0x020000 &&

  	    (etd->capabilities[0] & ETP_CAP_HAS_ROCKER)) {

  		/* rocker up */
  		input_report_key(dev, BTN_FORWARD, packet[0] & 0x40);
  		/* rocker down */
  		input_report_key(dev, BTN_BACK, packet[0] & 0x80);
  	}
  
  	input_sync(dev);
  }

  static void elantech_set_slot(struct input_dev *dev, int slot, bool active,
  			      unsigned int x, unsigned int y)
  {
  	input_mt_slot(dev, slot);
  	input_mt_report_slot_state(dev, MT_TOOL_FINGER, active);
  	if (active) {
  		input_report_abs(dev, ABS_MT_POSITION_X, x);
  		input_report_abs(dev, ABS_MT_POSITION_Y, y);
  	}
  }
  
  /* x1 < x2 and y1 < y2 when two fingers, x = y = 0 when not pressed */
  static void elantech_report_semi_mt_data(struct input_dev *dev,
  					 unsigned int num_fingers,
  					 unsigned int x1, unsigned int y1,
  					 unsigned int x2, unsigned int y2)
  {
  	elantech_set_slot(dev, 0, num_fingers != 0, x1, y1);
  	elantech_set_slot(dev, 1, num_fingers == 2, x2, y2);
  }

  /*
   * Interpret complete data packets and report absolute mode input events for
   * hardware version 2. (6 byte packets)
   */
  static void elantech_report_absolute_v2(struct psmouse *psmouse)
  {

  	struct elantech_data *etd = psmouse->private;

  	struct input_dev *dev = psmouse->dev;
  	unsigned char *packet = psmouse->packet;

  	unsigned int fingers, x1 = 0, y1 = 0, x2 = 0, y2 = 0;
  	unsigned int width = 0, pres = 0;

  
  	/* byte 0: n1  n0   .   .   .   .   R   L */
  	fingers = (packet[0] & 0xc0) >> 6;

  
  	switch (fingers) {

  	case 3:
  		/*
  		 * Same as one finger, except report of more than 3 fingers:
  		 * byte 3:  n4  .   w1  w0   .   .   .   .
  		 */
  		if (packet[3] & 0x80)
  			fingers = 4;
  		/* pass through... */

  	case 1:

  		/*

  		 * byte 1:  .   .   .   .  x11 x10 x9  x8

  		 * byte 2: x7  x6  x5  x4  x4  x2  x1  x0
  		 */

  		x1 = ((packet[1] & 0x0f) << 8) | packet[2];

  		/*

  		 * byte 4:  .   .   .   .  y11 y10 y9  y8

  		 * byte 5: y7  y6  y5  y4  y3  y2  y1  y0
  		 */

  		y1 = etd->y_max - (((packet[4] & 0x0f) << 8) | packet[5]);

  		pres = (packet[1] & 0xf0) | ((packet[4] & 0xf0) >> 4);
  		width = ((packet[0] & 0x30) >> 2) | ((packet[3] & 0x30) >> 4);

  		break;
  
  	case 2:

  		/*
  		 * The coordinate of each finger is reported separately
  		 * with a lower resolution for two finger touches:
  		 * byte 0:  .   .  ay8 ax8  .   .   .   .
  		 * byte 1: ax7 ax6 ax5 ax4 ax3 ax2 ax1 ax0
  		 */

  		x1 = (((packet[0] & 0x10) << 4) | packet[1]) << 2;

  		/* byte 2: ay7 ay6 ay5 ay4 ay3 ay2 ay1 ay0 */

  		y1 = etd->y_max -

  			((((packet[0] & 0x20) << 3) | packet[2]) << 2);

  		/*
  		 * byte 3:  .   .  by8 bx8  .   .   .   .
  		 * byte 4: bx7 bx6 bx5 bx4 bx3 bx2 bx1 bx0
  		 */

  		x2 = (((packet[3] & 0x10) << 4) | packet[4]) << 2;

  		/* byte 5: by7 by8 by5 by4 by3 by2 by1 by0 */

  		y2 = etd->y_max -

  			((((packet[3] & 0x20) << 3) | packet[5]) << 2);

  
  		/* Unknown so just report sensible values */
  		pres = 127;
  		width = 7;

  		break;
  	}

  	input_report_key(dev, BTN_TOUCH, fingers != 0);
  	if (fingers != 0) {
  		input_report_abs(dev, ABS_X, x1);
  		input_report_abs(dev, ABS_Y, y1);
  	}

  	elantech_report_semi_mt_data(dev, fingers, x1, y1, x2, y2);

  	input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
  	input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
  	input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);

  	input_report_key(dev, BTN_TOOL_QUADTAP, fingers == 4);

  	input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
  	input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);

  	if (etd->reports_pressure) {
  		input_report_abs(dev, ABS_PRESSURE, pres);
  		input_report_abs(dev, ABS_TOOL_WIDTH, width);
  	}

  
  	input_sync(dev);
  }

  static void elantech_report_trackpoint(struct psmouse *psmouse,
  				       int packet_type)
  {
  	/*
  	 * byte 0:  0   0  sx  sy   0   M   R   L
  	 * byte 1:~sx   0   0   0   0   0   0   0
  	 * byte 2:~sy   0   0   0   0   0   0   0
  	 * byte 3:  0   0 ~sy ~sx   0   1   1   0
  	 * byte 4: x7  x6  x5  x4  x3  x2  x1  x0
  	 * byte 5: y7  y6  y5  y4  y3  y2  y1  y0
  	 *
  	 * x and y are written in two's complement spread
  	 * over 9 bits with sx/sy the relative top bit and
  	 * x7..x0 and y7..y0 the lower bits.
  	 * The sign of y is opposite to what the input driver
  	 * expects for a relative movement
  	 */
  
  	struct elantech_data *etd = psmouse->private;
  	struct input_dev *tp_dev = etd->tp_dev;
  	unsigned char *packet = psmouse->packet;
  	int x, y;
  	u32 t;

  	t = get_unaligned_le32(&packet[0]);
  
  	switch (t & ~7U) {
  	case 0x06000030U:
  	case 0x16008020U:
  	case 0x26800010U:
  	case 0x36808000U:
  		x = packet[4] - (int)((packet[1]^0x80) << 1);
  		y = (int)((packet[2]^0x80) << 1) - packet[5];
  
  		input_report_key(tp_dev, BTN_LEFT, packet[0] & 0x01);
  		input_report_key(tp_dev, BTN_RIGHT, packet[0] & 0x02);
  		input_report_key(tp_dev, BTN_MIDDLE, packet[0] & 0x04);
  
  		input_report_rel(tp_dev, REL_X, x);
  		input_report_rel(tp_dev, REL_Y, y);
  
  		input_sync(tp_dev);
  
  		break;
  
  	default:
  		/* Dump unexpected packet sequences if debug=1 (default) */
  		if (etd->debug == 1)
  			elantech_packet_dump(psmouse);
  
  		break;
  	}
  }

  /*
   * Interpret complete data packets and report absolute mode input events for
   * hardware version 3. (12 byte packets for two fingers)
   */
  static void elantech_report_absolute_v3(struct psmouse *psmouse,
  					int packet_type)
  {
  	struct input_dev *dev = psmouse->dev;
  	struct elantech_data *etd = psmouse->private;
  	unsigned char *packet = psmouse->packet;
  	unsigned int fingers = 0, x1 = 0, y1 = 0, x2 = 0, y2 = 0;
  	unsigned int width = 0, pres = 0;
  
  	/* byte 0: n1  n0   .   .   .   .   R   L */
  	fingers = (packet[0] & 0xc0) >> 6;
  
  	switch (fingers) {
  	case 3:
  	case 1:
  		/*
  		 * byte 1:  .   .   .   .  x11 x10 x9  x8
  		 * byte 2: x7  x6  x5  x4  x4  x2  x1  x0
  		 */
  		x1 = ((packet[1] & 0x0f) << 8) | packet[2];
  		/*
  		 * byte 4:  .   .   .   .  y11 y10 y9  y8
  		 * byte 5: y7  y6  y5  y4  y3  y2  y1  y0
  		 */
  		y1 = etd->y_max - (((packet[4] & 0x0f) << 8) | packet[5]);
  		break;
  
  	case 2:
  		if (packet_type == PACKET_V3_HEAD) {
  			/*
  			 * byte 1:   .    .    .    .  ax11 ax10 ax9  ax8
  			 * byte 2: ax7  ax6  ax5  ax4  ax3  ax2  ax1  ax0
  			 */

  			etd->mt[0].x = ((packet[1] & 0x0f) << 8) | packet[2];

  			/*
  			 * byte 4:   .    .    .    .  ay11 ay10 ay9  ay8
  			 * byte 5: ay7  ay6  ay5  ay4  ay3  ay2  ay1  ay0
  			 */

  			etd->mt[0].y = etd->y_max -

  				(((packet[4] & 0x0f) << 8) | packet[5]);
  			/*
  			 * wait for next packet
  			 */
  			return;
  		}
  
  		/* packet_type == PACKET_V3_TAIL */

  		x1 = etd->mt[0].x;
  		y1 = etd->mt[0].y;

  		x2 = ((packet[1] & 0x0f) << 8) | packet[2];
  		y2 = etd->y_max - (((packet[4] & 0x0f) << 8) | packet[5]);
  		break;
  	}
  
  	pres = (packet[1] & 0xf0) | ((packet[4] & 0xf0) >> 4);
  	width = ((packet[0] & 0x30) >> 2) | ((packet[3] & 0x30) >> 4);
  
  	input_report_key(dev, BTN_TOUCH, fingers != 0);
  	if (fingers != 0) {
  		input_report_abs(dev, ABS_X, x1);
  		input_report_abs(dev, ABS_Y, y1);
  	}
  	elantech_report_semi_mt_data(dev, fingers, x1, y1, x2, y2);
  	input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
  	input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
  	input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);

  
  	/* For clickpads map both buttons to BTN_LEFT */
  	if (etd->fw_version & 0x001000) {
  		input_report_key(dev, BTN_LEFT, packet[0] & 0x03);
  	} else {
  		input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
  		input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);
  	}

  	input_report_abs(dev, ABS_PRESSURE, pres);
  	input_report_abs(dev, ABS_TOOL_WIDTH, width);
  
  	input_sync(dev);
  }

  static void elantech_input_sync_v4(struct psmouse *psmouse)
  {
  	struct input_dev *dev = psmouse->dev;

  	struct elantech_data *etd = psmouse->private;

  	unsigned char *packet = psmouse->packet;

  	/* For clickpads map both buttons to BTN_LEFT */
  	if (etd->fw_version & 0x001000) {
  		input_report_key(dev, BTN_LEFT, packet[0] & 0x03);
  	} else {
  		input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
  		input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);

  		input_report_key(dev, BTN_MIDDLE, packet[0] & 0x04);

  	}

  	input_mt_report_pointer_emulation(dev, true);
  	input_sync(dev);
  }
  
  static void process_packet_status_v4(struct psmouse *psmouse)
  {
  	struct input_dev *dev = psmouse->dev;
  	unsigned char *packet = psmouse->packet;
  	unsigned fingers;
  	int i;
  
  	/* notify finger state change */
  	fingers = packet[1] & 0x1f;
  	for (i = 0; i < ETP_MAX_FINGERS; i++) {
  		if ((fingers & (1 << i)) == 0) {
  			input_mt_slot(dev, i);
  			input_mt_report_slot_state(dev, MT_TOOL_FINGER, false);
  		}
  	}
  
  	elantech_input_sync_v4(psmouse);
  }
  
  static void process_packet_head_v4(struct psmouse *psmouse)
  {
  	struct input_dev *dev = psmouse->dev;
  	struct elantech_data *etd = psmouse->private;
  	unsigned char *packet = psmouse->packet;
  	int id = ((packet[3] & 0xe0) >> 5) - 1;
  	int pres, traces;
  
  	if (id < 0)
  		return;
  
  	etd->mt[id].x = ((packet[1] & 0x0f) << 8) | packet[2];
  	etd->mt[id].y = etd->y_max - (((packet[4] & 0x0f) << 8) | packet[5]);
  	pres = (packet[1] & 0xf0) | ((packet[4] & 0xf0) >> 4);
  	traces = (packet[0] & 0xf0) >> 4;
  
  	input_mt_slot(dev, id);
  	input_mt_report_slot_state(dev, MT_TOOL_FINGER, true);
  
  	input_report_abs(dev, ABS_MT_POSITION_X, etd->mt[id].x);
  	input_report_abs(dev, ABS_MT_POSITION_Y, etd->mt[id].y);
  	input_report_abs(dev, ABS_MT_PRESSURE, pres);
  	input_report_abs(dev, ABS_MT_TOUCH_MAJOR, traces * etd->width);
  	/* report this for backwards compatibility */
  	input_report_abs(dev, ABS_TOOL_WIDTH, traces);
  
  	elantech_input_sync_v4(psmouse);
  }
  
  static void process_packet_motion_v4(struct psmouse *psmouse)
  {
  	struct input_dev *dev = psmouse->dev;
  	struct elantech_data *etd = psmouse->private;
  	unsigned char *packet = psmouse->packet;
  	int weight, delta_x1 = 0, delta_y1 = 0, delta_x2 = 0, delta_y2 = 0;
  	int id, sid;
  
  	id = ((packet[0] & 0xe0) >> 5) - 1;
  	if (id < 0)
  		return;
  
  	sid = ((packet[3] & 0xe0) >> 5) - 1;
  	weight = (packet[0] & 0x10) ? ETP_WEIGHT_VALUE : 1;
  	/*
  	 * Motion packets give us the delta of x, y values of specific fingers,
  	 * but in two's complement. Let the compiler do the conversion for us.
  	 * Also _enlarge_ the numbers to int, in case of overflow.
  	 */
  	delta_x1 = (signed char)packet[1];
  	delta_y1 = (signed char)packet[2];
  	delta_x2 = (signed char)packet[4];
  	delta_y2 = (signed char)packet[5];
  
  	etd->mt[id].x += delta_x1 * weight;
  	etd->mt[id].y -= delta_y1 * weight;
  	input_mt_slot(dev, id);
  	input_report_abs(dev, ABS_MT_POSITION_X, etd->mt[id].x);
  	input_report_abs(dev, ABS_MT_POSITION_Y, etd->mt[id].y);
  
  	if (sid >= 0) {
  		etd->mt[sid].x += delta_x2 * weight;
  		etd->mt[sid].y -= delta_y2 * weight;
  		input_mt_slot(dev, sid);
  		input_report_abs(dev, ABS_MT_POSITION_X, etd->mt[sid].x);
  		input_report_abs(dev, ABS_MT_POSITION_Y, etd->mt[sid].y);
  	}
  
  	elantech_input_sync_v4(psmouse);
  }
  
  static void elantech_report_absolute_v4(struct psmouse *psmouse,
  					int packet_type)
  {
  	switch (packet_type) {
  	case PACKET_V4_STATUS:
  		process_packet_status_v4(psmouse);
  		break;
  
  	case PACKET_V4_HEAD:
  		process_packet_head_v4(psmouse);
  		break;
  
  	case PACKET_V4_MOTION:
  		process_packet_motion_v4(psmouse);
  		break;
  
  	case PACKET_UNKNOWN:
  	default:
  		/* impossible to get here */
  		break;
  	}
  }

  static int elantech_packet_check_v1(struct psmouse *psmouse)

  {
  	struct elantech_data *etd = psmouse->private;
  	unsigned char *packet = psmouse->packet;
  	unsigned char p1, p2, p3;
  
  	/* Parity bits are placed differently */

  	if (etd->fw_version < 0x020000) {

  		/* byte 0:  D   U  p1  p2   1  p3   R   L */
  		p1 = (packet[0] & 0x20) >> 5;
  		p2 = (packet[0] & 0x10) >> 4;
  	} else {
  		/* byte 0: n1  n0  p2  p1   1  p3   R   L */
  		p1 = (packet[0] & 0x10) >> 4;
  		p2 = (packet[0] & 0x20) >> 5;
  	}
  
  	p3 = (packet[0] & 0x04) >> 2;
  
  	return etd->parity[packet[1]] == p1 &&
  	       etd->parity[packet[2]] == p2 &&
  	       etd->parity[packet[3]] == p3;
  }

  static int elantech_debounce_check_v2(struct psmouse *psmouse)
  {
          /*
           * When we encounter packet that matches this exactly, it means the
           * hardware is in debounce status. Just ignore the whole packet.
           */
          const u8 debounce_packet[] = { 0x84, 0xff, 0xff, 0x02, 0xff, 0xff };
          unsigned char *packet = psmouse->packet;
  
          return !memcmp(packet, debounce_packet, sizeof(debounce_packet));
  }

  static int elantech_packet_check_v2(struct psmouse *psmouse)
  {
  	struct elantech_data *etd = psmouse->private;
  	unsigned char *packet = psmouse->packet;
  
  	/*
  	 * V2 hardware has two flavors. Older ones that do not report pressure,
  	 * and newer ones that reports pressure and width. With newer ones, all
  	 * packets (1, 2, 3 finger touch) have the same constant bits. With
  	 * older ones, 1/3 finger touch packets and 2 finger touch packets
  	 * have different constant bits.
  	 * With all three cases, if the constant bits are not exactly what I
  	 * expected, I consider them invalid.
  	 */
  	if (etd->reports_pressure)
  		return (packet[0] & 0x0c) == 0x04 &&
  		       (packet[3] & 0x0f) == 0x02;
  
  	if ((packet[0] & 0xc0) == 0x80)
  		return (packet[0] & 0x0c) == 0x0c &&
  		       (packet[3] & 0x0e) == 0x08;
  
  	return (packet[0] & 0x3c) == 0x3c &&
  	       (packet[1] & 0xf0) == 0x00 &&
  	       (packet[3] & 0x3e) == 0x38 &&
  	       (packet[4] & 0xf0) == 0x00;
  }

  /*

   * We check the constant bits to determine what packet type we get,

   * so packet checking is mandatory for v3 and later hardware.

   */
  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;
  
  	/*
  	 * check debounce first, it has the same signature in byte 0
  	 * and byte 3 as PACKET_V3_HEAD.
  	 */
  	if (!memcmp(packet, debounce_packet, sizeof(debounce_packet)))
  		return PACKET_DEBOUNCE;

  	/*
  	 * 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[3] & 0x0f) == 0x06)
  			return PACKET_TRACKPOINT;

  	}

  
  	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;

  	if (etd->tp_dev && (packet[3] & 0x0f) == 0x06)

  		return PACKET_TRACKPOINT;

  	/*
  	 * 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:
  		return PACKET_V4_STATUS;
  
  	case 1:

  		return PACKET_V4_HEAD;

  	case 2:

  		return PACKET_V4_MOTION;

  	}

  
  	return PACKET_UNKNOWN;
  }

  /*

   * Process byte stream from mouse and handle complete packets
   */
  static psmouse_ret_t elantech_process_byte(struct psmouse *psmouse)
  {
  	struct elantech_data *etd = psmouse->private;

  	int packet_type;

  
  	if (psmouse->pktcnt < psmouse->pktsize)
  		return PSMOUSE_GOOD_DATA;
  
  	if (etd->debug > 1)

  		elantech_packet_dump(psmouse);

  
  	switch (etd->hw_version) {
  	case 1:

  		if (etd->paritycheck && !elantech_packet_check_v1(psmouse))

  			return PSMOUSE_BAD_DATA;
  
  		elantech_report_absolute_v1(psmouse);
  		break;
  
  	case 2:

  		/* ignore debounce */
  		if (elantech_debounce_check_v2(psmouse))
  			return PSMOUSE_FULL_PACKET;

  		if (etd->paritycheck && !elantech_packet_check_v2(psmouse))
  			return PSMOUSE_BAD_DATA;

  		elantech_report_absolute_v2(psmouse);
  		break;

  
  	case 3:
  		packet_type = elantech_packet_check_v3(psmouse);

  		switch (packet_type) {
  		case PACKET_UNKNOWN:

  			return PSMOUSE_BAD_DATA;

  		case PACKET_DEBOUNCE:
  			/* ignore debounce */
  			break;
  
  		case PACKET_TRACKPOINT:
  			elantech_report_trackpoint(psmouse, packet_type);
  			break;
  
  		default:
  			elantech_report_absolute_v3(psmouse, packet_type);
  			break;
  		}

  		break;

  
  	case 4:
  		packet_type = elantech_packet_check_v4(psmouse);

  		switch (packet_type) {
  		case PACKET_UNKNOWN:

  			return PSMOUSE_BAD_DATA;

  		case PACKET_TRACKPOINT:
  			elantech_report_trackpoint(psmouse, packet_type);
  			break;
  
  		default:
  			elantech_report_absolute_v4(psmouse, packet_type);
  			break;
  		}

  		break;

  	}
  
  	return PSMOUSE_FULL_PACKET;
  }
  
  /*
   * Put the touchpad into absolute mode
   */
  static int elantech_set_absolute_mode(struct psmouse *psmouse)
  {
  	struct elantech_data *etd = psmouse->private;
  	unsigned char val;
  	int tries = ETP_READ_BACK_TRIES;
  	int rc = 0;
  
  	switch (etd->hw_version) {
  	case 1:
  		etd->reg_10 = 0x16;
  		etd->reg_11 = 0x8f;
  		if (elantech_write_reg(psmouse, 0x10, etd->reg_10) ||
  		    elantech_write_reg(psmouse, 0x11, etd->reg_11)) {
  			rc = -1;
  		}
  		break;
  
  	case 2:
  					/* Windows driver values */
  		etd->reg_10 = 0x54;
  		etd->reg_11 = 0x88;	/* 0x8a */
  		etd->reg_21 = 0x60;	/* 0x00 */
  		if (elantech_write_reg(psmouse, 0x10, etd->reg_10) ||
  		    elantech_write_reg(psmouse, 0x11, etd->reg_11) ||
  		    elantech_write_reg(psmouse, 0x21, etd->reg_21)) {
  			rc = -1;

  		}

  		break;
  
  	case 3:

  		if (etd->set_hw_resolution)
  			etd->reg_10 = 0x0b;
  		else

  			etd->reg_10 = 0x01;

  		if (elantech_write_reg(psmouse, 0x10, etd->reg_10))
  			rc = -1;
  
  		break;

  
  	case 4:
  		etd->reg_07 = 0x01;
  		if (elantech_write_reg(psmouse, 0x07, etd->reg_07))
  			rc = -1;
  
  		goto skip_readback_reg_10; /* v4 has no reg 0x10 to read */

  	}
  
  	if (rc == 0) {

  		/*

  		 * Read back reg 0x10. For hardware version 1 we must make
  		 * sure the absolute mode bit is set. For hardware version 2

  		 * the touchpad is probably initializing and not ready until

  		 * we read back the value we just wrote.

  		 */
  		do {
  			rc = elantech_read_reg(psmouse, 0x10, &val);
  			if (rc == 0)
  				break;
  			tries--;

  			elantech_debug("retrying read (%d).
  ", tries);

  			msleep(ETP_READ_BACK_DELAY);
  		} while (tries > 0);

  
  		if (rc) {

  			psmouse_err(psmouse,
  				    "failed to read back register 0x10.
  ");

  		} else if (etd->hw_version == 1 &&
  			   !(val & ETP_R10_ABSOLUTE_MODE)) {

  			psmouse_err(psmouse,
  				    "touchpad refuses to switch to absolute mode.
  ");

  			rc = -1;
  		}

  	}

   skip_readback_reg_10:

  	if (rc)

  		psmouse_err(psmouse, "failed to initialise registers.
  ");

  
  	return rc;
  }

  static int elantech_set_range(struct psmouse *psmouse,
  			      unsigned int *x_min, unsigned int *y_min,

  			      unsigned int *x_max, unsigned int *y_max,
  			      unsigned int *width)

  {
  	struct elantech_data *etd = psmouse->private;

  	unsigned char param[3];

  	unsigned char traces;

  
  	switch (etd->hw_version) {
  	case 1:
  		*x_min = ETP_XMIN_V1;
  		*y_min = ETP_YMIN_V1;
  		*x_max = ETP_XMAX_V1;
  		*y_max = ETP_YMAX_V1;
  		break;
  
  	case 2:
  		if (etd->fw_version == 0x020800 ||
  		    etd->fw_version == 0x020b00 ||
  		    etd->fw_version == 0x020030) {
  			*x_min = ETP_XMIN_V2;
  			*y_min = ETP_YMIN_V2;
  			*x_max = ETP_XMAX_V2;
  			*y_max = ETP_YMAX_V2;
  		} else {

  			int i;
  			int fixed_dpi;

  			i = (etd->fw_version > 0x020800 &&
  			     etd->fw_version < 0x020900) ? 1 : 2;

  			if (etd->send_cmd(psmouse, ETP_FW_ID_QUERY, param))

  				return -1;
  
  			fixed_dpi = param[1] & 0x10;
  
  			if (((etd->fw_version >> 16) == 0x14) && fixed_dpi) {

  				if (etd->send_cmd(psmouse, ETP_SAMPLE_QUERY, param))

  					return -1;
  
  				*x_max = (etd->capabilities[1] - i) * param[1] / 2;
  				*y_max = (etd->capabilities[2] - i) * param[2] / 2;
  			} else if (etd->fw_version == 0x040216) {
  				*x_max = 819;
  				*y_max = 405;
  			} else if (etd->fw_version == 0x040219 || etd->fw_version == 0x040215) {
  				*x_max = 900;
  				*y_max = 500;
  			} else {
  				*x_max = (etd->capabilities[1] - i) * 64;
  				*y_max = (etd->capabilities[2] - i) * 64;
  			}

  		}
  		break;

  
  	case 3:

  		if (etd->send_cmd(psmouse, ETP_FW_ID_QUERY, param))

  			return -1;
  
  		*x_max = (0x0f & param[0]) << 8 | param[1];
  		*y_max = (0xf0 & param[0]) << 4 | param[2];
  		break;

  
  	case 4:

  		if (etd->send_cmd(psmouse, ETP_FW_ID_QUERY, param))

  			return -1;
  
  		*x_max = (0x0f & param[0]) << 8 | param[1];
  		*y_max = (0xf0 & param[0]) << 4 | param[2];
  		traces = etd->capabilities[1];
  		if ((traces < 2) || (traces > *x_max))
  			return -1;
  
  		*width = *x_max / (traces - 1);
  		break;

  	}

  
  	return 0;

  }

  /*

   * (value from firmware) * 10 + 790 = dpi
   * we also have to convert dpi to dots/mm (*10/254 to avoid floating point)
   */
  static unsigned int elantech_convert_res(unsigned int val)
  {
  	return (val * 10 + 790) * 10 / 254;
  }
  
  static int elantech_get_resolution_v4(struct psmouse *psmouse,
  				      unsigned int *x_res,
  				      unsigned int *y_res)
  {
  	unsigned char param[3];
  
  	if (elantech_send_cmd(psmouse, ETP_RESOLUTION_QUERY, param))
  		return -1;
  
  	*x_res = elantech_convert_res(param[1] & 0x0f);
  	*y_res = elantech_convert_res((param[1] & 0xf0) >> 4);
  
  	return 0;
  }
  
  /*

   * Advertise INPUT_PROP_BUTTONPAD for clickpads. The testing of bit 12 in
   * fw_version for this is based on the following fw_version & caps table:
   *
   * Laptop-model:           fw_version:     caps:           buttons:
   * Acer S3                 0x461f00        10, 13, 0e      clickpad
   * Acer S7-392             0x581f01        50, 17, 0d      clickpad
   * Acer V5-131             0x461f02        01, 16, 0c      clickpad
   * Acer V5-551             0x461f00        ?               clickpad
   * Asus K53SV              0x450f01        78, 15, 0c      2 hw buttons
   * Asus G46VW              0x460f02        00, 18, 0c      2 hw buttons
   * Asus G750JX             0x360f00        00, 16, 0c      2 hw buttons
   * Asus UX31               0x361f00        20, 15, 0e      clickpad
   * Asus UX32VD             0x361f02        00, 15, 0e      clickpad
   * Avatar AVIU-145A2       0x361f00        ?               clickpad

   * 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 (*)

   * Lenovo L530             0x350f02        b9, 15, 0c      2 hw buttons (*)

   * Samsung NF210           0x150b00        78, 14, 0a      2 hw buttons
   * Samsung NP770Z5E        0x575f01        10, 15, 0f      clickpad
   * Samsung NP700Z5B        0x361f06        21, 15, 0f      clickpad
   * Samsung NP900X3E-A02    0x575f03        ?               clickpad
   * Samsung NP-QX410        0x851b00        19, 14, 0c      clickpad
   * Samsung RC512           0x450f00        08, 15, 0c      2 hw buttons
   * Samsung RF710           0x450f00        ?               2 hw buttons
   * System76 Pangolin       0x250f01        ?               2 hw buttons
   * (*) + 3 trackpoint buttons

   * (**) + 0 trackpoint buttons
   * Note: Lenovo L430 and Lenovo L430 have the same fw_version/caps

   */
  static void elantech_set_buttonpad_prop(struct psmouse *psmouse)
  {
  	struct input_dev *dev = psmouse->dev;
  	struct elantech_data *etd = psmouse->private;
  
  	if (etd->fw_version & 0x001000) {
  		__set_bit(INPUT_PROP_BUTTONPAD, dev->propbit);
  		__clear_bit(BTN_RIGHT, dev->keybit);
  	}
  }
  
  /*

   * Some hw_version 4 models do have a middle button
   */
  static const struct dmi_system_id elantech_dmi_has_middle_button[] = {
  #if defined(CONFIG_DMI) && defined(CONFIG_X86)
  	{
  		/* Fujitsu H730 has a middle button */
  		.matches = {
  			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
  			DMI_MATCH(DMI_PRODUCT_NAME, "CELSIUS H730"),
  		},
  	},
  #endif
  	{ }
  };
  
  /*

   * Set the appropriate event bits for the input subsystem
   */

  static int elantech_set_input_params(struct psmouse *psmouse)

  {
  	struct input_dev *dev = psmouse->dev;
  	struct elantech_data *etd = psmouse->private;

  	unsigned int x_min = 0, y_min = 0, x_max = 0, y_max = 0, width = 0;

  	unsigned int x_res = 0, y_res = 0;

  	if (elantech_set_range(psmouse, &x_min, &y_min, &x_max, &y_max, &width))

  		return -1;

  	__set_bit(INPUT_PROP_POINTER, dev->propbit);

  	__set_bit(EV_KEY, dev->evbit);
  	__set_bit(EV_ABS, dev->evbit);

  	__clear_bit(EV_REL, dev->evbit);

  
  	__set_bit(BTN_LEFT, dev->keybit);

  	if (dmi_check_system(elantech_dmi_has_middle_button))
  		__set_bit(BTN_MIDDLE, dev->keybit);

  	__set_bit(BTN_RIGHT, dev->keybit);
  
  	__set_bit(BTN_TOUCH, dev->keybit);
  	__set_bit(BTN_TOOL_FINGER, dev->keybit);
  	__set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
  	__set_bit(BTN_TOOL_TRIPLETAP, dev->keybit);
  
  	switch (etd->hw_version) {
  	case 1:
  		/* Rocker button */

  		if (etd->fw_version < 0x020000 &&

  		    (etd->capabilities[0] & ETP_CAP_HAS_ROCKER)) {

  			__set_bit(BTN_FORWARD, dev->keybit);
  			__set_bit(BTN_BACK, dev->keybit);
  		}

  		input_set_abs_params(dev, ABS_X, x_min, x_max, 0, 0);
  		input_set_abs_params(dev, ABS_Y, y_min, y_max, 0, 0);

  		break;
  
  	case 2:

  		__set_bit(BTN_TOOL_QUADTAP, dev->keybit);

  		__set_bit(INPUT_PROP_SEMI_MT, dev->propbit);
  		/* fall through */
  	case 3:

  		if (etd->hw_version == 3)
  			elantech_set_buttonpad_prop(psmouse);

  		input_set_abs_params(dev, ABS_X, x_min, x_max, 0, 0);
  		input_set_abs_params(dev, ABS_Y, y_min, y_max, 0, 0);

  		if (etd->reports_pressure) {
  			input_set_abs_params(dev, ABS_PRESSURE, ETP_PMIN_V2,
  					     ETP_PMAX_V2, 0, 0);
  			input_set_abs_params(dev, ABS_TOOL_WIDTH, ETP_WMIN_V2,
  					     ETP_WMAX_V2, 0, 0);
  		}

  		input_mt_init_slots(dev, 2, 0);

  		input_set_abs_params(dev, ABS_MT_POSITION_X, x_min, x_max, 0, 0);
  		input_set_abs_params(dev, ABS_MT_POSITION_Y, y_min, y_max, 0, 0);

  		break;

  
  	case 4:

  		if (elantech_get_resolution_v4(psmouse, &x_res, &y_res)) {
  			/*
  			 * if query failed, print a warning and leave the values
  			 * zero to resemble synaptics.c behavior.
  			 */
  			psmouse_warn(psmouse, "couldn't query resolution data.
  ");
  		}

  		elantech_set_buttonpad_prop(psmouse);

  		__set_bit(BTN_TOOL_QUADTAP, dev->keybit);
  		/* For X to recognize me as touchpad. */
  		input_set_abs_params(dev, ABS_X, x_min, x_max, 0, 0);
  		input_set_abs_params(dev, ABS_Y, y_min, y_max, 0, 0);

  		input_abs_set_res(dev, ABS_X, x_res);
  		input_abs_set_res(dev, ABS_Y, y_res);

  		/*
  		 * range of pressure and width is the same as v2,
  		 * report ABS_PRESSURE, ABS_TOOL_WIDTH for compatibility.
  		 */
  		input_set_abs_params(dev, ABS_PRESSURE, ETP_PMIN_V2,
  				     ETP_PMAX_V2, 0, 0);
  		input_set_abs_params(dev, ABS_TOOL_WIDTH, ETP_WMIN_V2,
  				     ETP_WMAX_V2, 0, 0);
  		/* Multitouch capable pad, up to 5 fingers. */

  		input_mt_init_slots(dev, ETP_MAX_FINGERS, 0);

  		input_set_abs_params(dev, ABS_MT_POSITION_X, x_min, x_max, 0, 0);
  		input_set_abs_params(dev, ABS_MT_POSITION_Y, y_min, y_max, 0, 0);

  		input_abs_set_res(dev, ABS_MT_POSITION_X, x_res);
  		input_abs_set_res(dev, ABS_MT_POSITION_Y, y_res);

  		input_set_abs_params(dev, ABS_MT_PRESSURE, ETP_PMIN_V2,
  				     ETP_PMAX_V2, 0, 0);
  		/*
  		 * The firmware reports how many trace lines the finger spans,
  		 * convert to surface unit as Protocol-B requires.
  		 */
  		input_set_abs_params(dev, ABS_MT_TOUCH_MAJOR, 0,
  				     ETP_WMAX_V2 * width, 0, 0);
  		break;

  	}

  
  	etd->y_max = y_max;

  	etd->width = width;

  
  	return 0;

  }
  
  struct elantech_attr_data {
  	size_t		field_offset;
  	unsigned char	reg;
  };
  
  /*
   * Display a register value by reading a sysfs entry
   */
  static ssize_t elantech_show_int_attr(struct psmouse *psmouse, void *data,
  					char *buf)
  {
  	struct elantech_data *etd = psmouse->private;
  	struct elantech_attr_data *attr = data;
  	unsigned char *reg = (unsigned char *) etd + attr->field_offset;
  	int rc = 0;
  
  	if (attr->reg)
  		rc = elantech_read_reg(psmouse, attr->reg, reg);
  
  	return sprintf(buf, "0x%02x
  ", (attr->reg && rc) ? -1 : *reg);
  }
  
  /*
   * Write a register value by writing a sysfs entry
   */
  static ssize_t elantech_set_int_attr(struct psmouse *psmouse,
  				     void *data, const char *buf, size_t count)
  {
  	struct elantech_data *etd = psmouse->private;
  	struct elantech_attr_data *attr = data;
  	unsigned char *reg = (unsigned char *) etd + attr->field_offset;

  	unsigned char value;

  	int err;

  	err = kstrtou8(buf, 16, &value);

  	if (err)
  		return err;

  	/* Do we need to preserve some bits for version 2 hardware too? */
  	if (etd->hw_version == 1) {
  		if (attr->reg == 0x10)
  			/* Force absolute mode always on */
  			value |= ETP_R10_ABSOLUTE_MODE;
  		else if (attr->reg == 0x11)
  			/* Force 4 byte mode always on */
  			value |= ETP_R11_4_BYTE_MODE;
  	}
  
  	if (!attr->reg || elantech_write_reg(psmouse, attr->reg, value) == 0)
  		*reg = value;
  
  	return count;
  }
  
  #define ELANTECH_INT_ATTR(_name, _register)				\
  	static struct elantech_attr_data elantech_attr_##_name = {	\
  		.field_offset = offsetof(struct elantech_data, _name),	\
  		.reg = _register,					\
  	};								\
  	PSMOUSE_DEFINE_ATTR(_name, S_IWUSR | S_IRUGO,			\
  			    &elantech_attr_##_name,			\
  			    elantech_show_int_attr,			\
  			    elantech_set_int_attr)

  ELANTECH_INT_ATTR(reg_07, 0x07);

  ELANTECH_INT_ATTR(reg_10, 0x10);
  ELANTECH_INT_ATTR(reg_11, 0x11);
  ELANTECH_INT_ATTR(reg_20, 0x20);
  ELANTECH_INT_ATTR(reg_21, 0x21);
  ELANTECH_INT_ATTR(reg_22, 0x22);
  ELANTECH_INT_ATTR(reg_23, 0x23);
  ELANTECH_INT_ATTR(reg_24, 0x24);
  ELANTECH_INT_ATTR(reg_25, 0x25);
  ELANTECH_INT_ATTR(reg_26, 0x26);
  ELANTECH_INT_ATTR(debug, 0);
  ELANTECH_INT_ATTR(paritycheck, 0);

  ELANTECH_INT_ATTR(crc_enabled, 0);

  
  static struct attribute *elantech_attrs[] = {

  	&psmouse_attr_reg_07.dattr.attr,

  	&psmouse_attr_reg_10.dattr.attr,
  	&psmouse_attr_reg_11.dattr.attr,
  	&psmouse_attr_reg_20.dattr.attr,
  	&psmouse_attr_reg_21.dattr.attr,
  	&psmouse_attr_reg_22.dattr.attr,
  	&psmouse_attr_reg_23.dattr.attr,
  	&psmouse_attr_reg_24.dattr.attr,
  	&psmouse_attr_reg_25.dattr.attr,
  	&psmouse_attr_reg_26.dattr.attr,
  	&psmouse_attr_debug.dattr.attr,
  	&psmouse_attr_paritycheck.dattr.attr,

  	&psmouse_attr_crc_enabled.dattr.attr,

  	NULL
  };
  
  static struct attribute_group elantech_attr_group = {
  	.attrs = elantech_attrs,
  };

  static bool elantech_is_signature_valid(const unsigned char *param)
  {
  	static const unsigned char rates[] = { 200, 100, 80, 60, 40, 20, 10 };
  	int i;
  
  	if (param[0] == 0)
  		return false;
  
  	if (param[1] == 0)
  		return true;

  	/*
  	 * Some models have a revision higher then 20. Meaning param[2] may
  	 * be 10 or 20, skip the rates check for these.
  	 */
  	if (param[0] == 0x46 && (param[1] & 0xef) == 0x0f && param[2] < 40)
  		return true;

  	for (i = 0; i < ARRAY_SIZE(rates); i++)
  		if (param[2] == rates[i])
  			return false;
  
  	return true;
  }

  /*
   * Use magic knock to detect Elantech touchpad
   */

  int elantech_detect(struct psmouse *psmouse, bool set_properties)

  {
  	struct ps2dev *ps2dev = &psmouse->ps2dev;
  	unsigned char param[3];
  
  	ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_RESET_DIS);
  
  	if (ps2_command(ps2dev,  NULL, PSMOUSE_CMD_DISABLE) ||
  	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
  	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
  	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
  	    ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO)) {

  		psmouse_dbg(psmouse, "sending Elantech magic knock failed.
  ");

  		return -1;
  	}
  
  	/*
  	 * Report this in case there are Elantech models that use a different
  	 * set of magic numbers
  	 */

  	if (param[0] != 0x3c || param[1] != 0x03 ||
  	    (param[2] != 0xc8 && param[2] != 0x00)) {

  		psmouse_dbg(psmouse,
  			    "unexpected magic knock result 0x%02x, 0x%02x, 0x%02x.
  ",
  			    param[0], param[1], param[2]);

  		return -1;
  	}
  
  	/*
  	 * Query touchpad's firmware version and see if it reports known
  	 * value to avoid mis-detection. Logitech mice are known to respond
  	 * to Elantech magic knock and there might be more.
  	 */
  	if (synaptics_send_cmd(psmouse, ETP_FW_VERSION_QUERY, param)) {

  		psmouse_dbg(psmouse, "failed to query firmware version.
  ");

  		return -1;
  	}

  	psmouse_dbg(psmouse,
  		    "Elantech version query result 0x%02x, 0x%02x, 0x%02x.
  ",
  		    param[0], param[1], param[2]);

  	if (!elantech_is_signature_valid(param)) {

  		psmouse_dbg(psmouse,
  			    "Probably not a real Elantech touchpad. Aborting.
  ");

  		return -1;

  	}
  
  	if (set_properties) {
  		psmouse->vendor = "Elantech";
  		psmouse->name = "Touchpad";
  	}
  
  	return 0;
  }
  
  /*
   * Clean up sysfs entries when disconnecting
   */
  static void elantech_disconnect(struct psmouse *psmouse)
  {

  	struct elantech_data *etd = psmouse->private;
  
  	if (etd->tp_dev)
  		input_unregister_device(etd->tp_dev);

  	sysfs_remove_group(&psmouse->ps2dev.serio->dev.kobj,
  			   &elantech_attr_group);
  	kfree(psmouse->private);
  	psmouse->private = NULL;
  }
  
  /*
   * Put the touchpad back into absolute mode when reconnecting
   */
  static int elantech_reconnect(struct psmouse *psmouse)
  {

  	psmouse_reset(psmouse);

  	if (elantech_detect(psmouse, 0))
  		return -1;
  
  	if (elantech_set_absolute_mode(psmouse)) {

  		psmouse_err(psmouse,
  			    "failed to put touchpad back into absolute mode.
  ");

  		return -1;
  	}
  
  	return 0;
  }
  
  /*

   * Some hw_version 4 models do not work with crc_disabled
   */
  static const struct dmi_system_id elantech_dmi_force_crc_enabled[] = {
  #if defined(CONFIG_DMI) && defined(CONFIG_X86)
  	{
  		/* Fujitsu H730 does not work with crc_enabled == 0 */
  		.matches = {
  			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
  			DMI_MATCH(DMI_PRODUCT_NAME, "CELSIUS H730"),
  		},
  	},
  #endif
  	{ }
  };
  
  /*

   * Some hw_version 3 models go into error state when we try to set
   * bit 3 and/or bit 1 of r10.

   */
  static const struct dmi_system_id no_hw_res_dmi_table[] = {
  #if defined(CONFIG_DMI) && defined(CONFIG_X86)
  	{
  		/* Gigabyte U2442 */
  		.matches = {
  			DMI_MATCH(DMI_SYS_VENDOR, "GIGABYTE"),
  			DMI_MATCH(DMI_PRODUCT_NAME, "U2442"),
  		},
  	},
  #endif
  	{ }
  };
  
  /*

   * determine hardware version and set some properties according to it.
   */

  static int elantech_set_properties(struct elantech_data *etd)

  {

  	/* This represents the version of IC body. */

  	int ver = (etd->fw_version & 0x0f0000) >> 16;

  	/* Early version of Elan touchpads doesn't obey the rule. */

  	if (etd->fw_version < 0x020030 || etd->fw_version == 0x020600)
  		etd->hw_version = 1;

  	else {
  		switch (ver) {
  		case 2:
  		case 4:
  			etd->hw_version = 2;
  			break;
  		case 5:
  			etd->hw_version = 3;
  			break;
  		case 6:

  		case 7:

  		case 8:

  		case 9:

  		case 10:
  		case 13:

  			etd->hw_version = 4;
  			break;
  		default:
  			return -1;
  		}
  	}

  	/* decide which send_cmd we're gonna use early */
  	etd->send_cmd = etd->hw_version >= 3 ? elantech_send_cmd :
  					       synaptics_send_cmd;
  
  	/* Turn on packet checking by default */

  	etd->paritycheck = 1;
  
  	/*
  	 * This firmware suffers from misreporting coordinates when
  	 * a touch action starts causing the mouse cursor or scrolled page
  	 * to jump. Enable a workaround.
  	 */
  	etd->jumpy_cursor =
  		(etd->fw_version == 0x020022 || etd->fw_version == 0x020600);

  	if (etd->hw_version > 1) {

  		/* For now show extra debug information */
  		etd->debug = 1;
  
  		if (etd->fw_version >= 0x020800)
  			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 ||
  			   dmi_check_system(elantech_dmi_force_crc_enabled);

  	/* Enable real hardware resolution on hw_version 3 ? */
  	etd->set_hw_resolution = !dmi_check_system(no_hw_res_dmi_table);

  	return 0;

  }
  
  /*

   * Initialize the touchpad and create sysfs entries
   */
  int elantech_init(struct psmouse *psmouse)
  {
  	struct elantech_data *etd;

  	int i;
  	int error = -EINVAL;

  	unsigned char param[3];

  	struct input_dev *tp_dev;

  	psmouse->private = etd = kzalloc(sizeof(struct elantech_data), GFP_KERNEL);

  	if (!etd)

  		return -ENOMEM;

  	psmouse_reset(psmouse);

  	etd->parity[0] = 1;
  	for (i = 1; i < 256; i++)
  		etd->parity[i] = etd->parity[i & (i - 1)] ^ 1;
  
  	/*

  	 * Do the version query again so we can store the result

  	 */
  	if (synaptics_send_cmd(psmouse, ETP_FW_VERSION_QUERY, param)) {

  		psmouse_err(psmouse, "failed to query firmware version.
  ");

  		goto init_fail;
  	}

  	etd->fw_version = (param[0] << 16) | (param[1] << 8) | param[2];

  
  	if (elantech_set_properties(etd)) {

  		psmouse_err(psmouse, "unknown hardware version, aborting...
  ");

  		goto init_fail;
  	}

  	psmouse_info(psmouse,
  		     "assuming hardware version %d (with firmware version 0x%02x%02x%02x)
  ",
  		     etd->hw_version, param[0], param[1], param[2]);

  	if (etd->send_cmd(psmouse, ETP_CAPABILITIES_QUERY,

  	    etd->capabilities)) {

  		psmouse_err(psmouse, "failed to query capabilities.
  ");

  		goto init_fail;
  	}

  	psmouse_info(psmouse,
  		     "Synaptics capabilities query result 0x%02x, 0x%02x, 0x%02x.
  ",
  		     etd->capabilities[0], etd->capabilities[1],
  		     etd->capabilities[2]);

  
  	if (elantech_set_absolute_mode(psmouse)) {

  		psmouse_err(psmouse,
  			    "failed to put touchpad into absolute mode.
  ");

  		goto init_fail;
  	}

  	if (elantech_set_input_params(psmouse)) {

  		psmouse_err(psmouse, "failed to query touchpad range.
  ");

  		goto init_fail;
  	}

  
  	error = sysfs_create_group(&psmouse->ps2dev.serio->dev.kobj,
  				   &elantech_attr_group);
  	if (error) {

  		psmouse_err(psmouse,
  			    "failed to create sysfs attributes, error: %d.
  ",
  			    error);

  		goto init_fail;
  	}

  	/* The MSB indicates the presence of the trackpoint */
  	if ((etd->capabilities[0] & 0x80) == 0x80) {
  		tp_dev = input_allocate_device();
  
  		if (!tp_dev) {
  			error = -ENOMEM;
  			goto init_fail_tp_alloc;
  		}
  
  		etd->tp_dev = tp_dev;
  		snprintf(etd->tp_phys, sizeof(etd->tp_phys), "%s/input1",
  			psmouse->ps2dev.serio->phys);
  		tp_dev->phys = etd->tp_phys;
  		tp_dev->name = "Elantech PS/2 TrackPoint";
  		tp_dev->id.bustype = BUS_I8042;
  		tp_dev->id.vendor  = 0x0002;
  		tp_dev->id.product = PSMOUSE_ELANTECH;
  		tp_dev->id.version = 0x0000;
  		tp_dev->dev.parent = &psmouse->ps2dev.serio->dev;
  		tp_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REL);
  		tp_dev->relbit[BIT_WORD(REL_X)] =
  			BIT_MASK(REL_X) | BIT_MASK(REL_Y);
  		tp_dev->keybit[BIT_WORD(BTN_LEFT)] =
  			BIT_MASK(BTN_LEFT) | BIT_MASK(BTN_MIDDLE) |
  			BIT_MASK(BTN_RIGHT);

  		__set_bit(INPUT_PROP_POINTER, tp_dev->propbit);

  		__set_bit(INPUT_PROP_POINTING_STICK, tp_dev->propbit);

  		error = input_register_device(etd->tp_dev);
  		if (error < 0)
  			goto init_fail_tp_reg;
  	}

  	psmouse->protocol_handler = elantech_process_byte;
  	psmouse->disconnect = elantech_disconnect;
  	psmouse->reconnect = elantech_reconnect;

  	psmouse->pktsize = etd->hw_version > 1 ? 6 : 4;

  
  	return 0;

   init_fail_tp_reg:
  	input_free_device(tp_dev);
   init_fail_tp_alloc:
  	sysfs_remove_group(&psmouse->ps2dev.serio->dev.kobj,
  			   &elantech_attr_group);

   init_fail:

  	psmouse_reset(psmouse);

  	kfree(etd);

  	return error;

  }