/*
   * Cypress APA trackpad with I2C interface
   *
   * Author: Dudley Du <dudl@cypress.com>
   * Further cleanup and restructuring by:
   *   Daniel Kurtz <djkurtz@chromium.org>
   *   Benson Leung <bleung@chromium.org>
   *
   * Copyright (C) 2011-2012 Cypress Semiconductor, Inc.
   * Copyright (C) 2011-2012 Google, Inc.
   *
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file COPYING in the main directory of this archive for
   * more details.
   */
  
  #include <linux/delay.h>
  #include <linux/i2c.h>
  #include <linux/input.h>
  #include <linux/input/mt.h>
  #include <linux/interrupt.h>
  #include <linux/module.h>
  #include <linux/slab.h>
  
  /* APA trackpad firmware generation */
  #define CYAPA_GEN3   0x03   /* support MT-protocol B with tracking ID. */
  
  #define CYAPA_NAME   "Cypress APA Trackpad (cyapa)"
  
  /* commands for read/write registers of Cypress trackpad */
  #define CYAPA_CMD_SOFT_RESET       0x00
  #define CYAPA_CMD_POWER_MODE       0x01
  #define CYAPA_CMD_DEV_STATUS       0x02
  #define CYAPA_CMD_GROUP_DATA       0x03
  #define CYAPA_CMD_GROUP_CMD        0x04
  #define CYAPA_CMD_GROUP_QUERY      0x05
  #define CYAPA_CMD_BL_STATUS        0x06
  #define CYAPA_CMD_BL_HEAD          0x07
  #define CYAPA_CMD_BL_CMD           0x08
  #define CYAPA_CMD_BL_DATA          0x09
  #define CYAPA_CMD_BL_ALL           0x0a
  #define CYAPA_CMD_BLK_PRODUCT_ID   0x0b
  #define CYAPA_CMD_BLK_HEAD         0x0c
  
  /* report data start reg offset address. */
  #define DATA_REG_START_OFFSET  0x0000
  
  #define BL_HEAD_OFFSET 0x00
  #define BL_DATA_OFFSET 0x10
  
  /*
   * Operational Device Status Register
   *
   * bit 7: Valid interrupt source
   * bit 6 - 4: Reserved
   * bit 3 - 2: Power status
   * bit 1 - 0: Device status
   */
  #define REG_OP_STATUS     0x00
  #define OP_STATUS_SRC     0x80
  #define OP_STATUS_POWER   0x0c
  #define OP_STATUS_DEV     0x03
  #define OP_STATUS_MASK (OP_STATUS_SRC | OP_STATUS_POWER | OP_STATUS_DEV)
  
  /*
   * Operational Finger Count/Button Flags Register
   *
   * bit 7 - 4: Number of touched finger
   * bit 3: Valid data
   * bit 2: Middle Physical Button
   * bit 1: Right Physical Button
   * bit 0: Left physical Button
   */
  #define REG_OP_DATA1       0x01
  #define OP_DATA_VALID      0x08
  #define OP_DATA_MIDDLE_BTN 0x04
  #define OP_DATA_RIGHT_BTN  0x02
  #define OP_DATA_LEFT_BTN   0x01
  #define OP_DATA_BTN_MASK (OP_DATA_MIDDLE_BTN | OP_DATA_RIGHT_BTN | \
  			  OP_DATA_LEFT_BTN)
  
  /*
   * Bootloader Status Register
   *
   * bit 7: Busy
   * bit 6 - 5: Reserved
   * bit 4: Bootloader running
   * bit 3 - 1: Reserved
   * bit 0: Checksum valid
   */
  #define REG_BL_STATUS        0x01
  #define BL_STATUS_BUSY       0x80
  #define BL_STATUS_RUNNING    0x10
  #define BL_STATUS_DATA_VALID 0x08
  #define BL_STATUS_CSUM_VALID 0x01
  
  /*
   * Bootloader Error Register
   *
   * bit 7: Invalid
   * bit 6: Invalid security key
   * bit 5: Bootloading
   * bit 4: Command checksum
   * bit 3: Flash protection error
   * bit 2: Flash checksum error
   * bit 1 - 0: Reserved
   */
  #define REG_BL_ERROR         0x02
  #define BL_ERROR_INVALID     0x80
  #define BL_ERROR_INVALID_KEY 0x40
  #define BL_ERROR_BOOTLOADING 0x20
  #define BL_ERROR_CMD_CSUM    0x10
  #define BL_ERROR_FLASH_PROT  0x08
  #define BL_ERROR_FLASH_CSUM  0x04
  
  #define BL_STATUS_SIZE  3  /* length of bootloader status registers */
  #define BLK_HEAD_BYTES 32
  
  #define PRODUCT_ID_SIZE  16
  #define QUERY_DATA_SIZE  27
  #define REG_PROTOCOL_GEN_QUERY_OFFSET  20
  
  #define REG_OFFSET_DATA_BASE     0x0000
  #define REG_OFFSET_COMMAND_BASE  0x0028
  #define REG_OFFSET_QUERY_BASE    0x002a
  
  #define CAPABILITY_LEFT_BTN_MASK	(0x01 << 3)
  #define CAPABILITY_RIGHT_BTN_MASK	(0x01 << 4)
  #define CAPABILITY_MIDDLE_BTN_MASK	(0x01 << 5)
  #define CAPABILITY_BTN_MASK  (CAPABILITY_LEFT_BTN_MASK | \
  			      CAPABILITY_RIGHT_BTN_MASK | \
  			      CAPABILITY_MIDDLE_BTN_MASK)
  
  #define CYAPA_OFFSET_SOFT_RESET  REG_OFFSET_COMMAND_BASE
  
  #define REG_OFFSET_POWER_MODE (REG_OFFSET_COMMAND_BASE + 1)
  
  #define PWR_MODE_MASK   0xfc
  #define PWR_MODE_FULL_ACTIVE (0x3f << 2)
  #define PWR_MODE_IDLE        (0x05 << 2) /* default sleep time is 50 ms. */
  #define PWR_MODE_OFF         (0x00 << 2)
  
  #define PWR_STATUS_MASK      0x0c
  #define PWR_STATUS_ACTIVE    (0x03 << 2)
  #define PWR_STATUS_IDLE      (0x02 << 2)
  #define PWR_STATUS_OFF       (0x00 << 2)
  
  /*
   * CYAPA trackpad device states.
   * Used in register 0x00, bit1-0, DeviceStatus field.
   * Other values indicate device is in an abnormal state and must be reset.
   */
  #define CYAPA_DEV_NORMAL  0x03
  #define CYAPA_DEV_BUSY    0x01
  
  enum cyapa_state {
  	CYAPA_STATE_OP,
  	CYAPA_STATE_BL_IDLE,
  	CYAPA_STATE_BL_ACTIVE,
  	CYAPA_STATE_BL_BUSY,
  	CYAPA_STATE_NO_DEVICE,
  };
  
  
  struct cyapa_touch {
  	/*
  	 * high bits or x/y position value
  	 * bit 7 - 4: high 4 bits of x position value
  	 * bit 3 - 0: high 4 bits of y position value
  	 */
  	u8 xy_hi;
  	u8 x_lo;  /* low 8 bits of x position value. */
  	u8 y_lo;  /* low 8 bits of y position value. */
  	u8 pressure;
  	/* id range is 1 - 15.  It is incremented with every new touch. */
  	u8 id;
  } __packed;
  
  /* The touch.id is used as the MT slot id, thus max MT slot is 15 */
  #define CYAPA_MAX_MT_SLOTS  15
  
  struct cyapa_reg_data {
  	/*
  	 * bit 0 - 1: device status
  	 * bit 3 - 2: power mode
  	 * bit 6 - 4: reserved
  	 * bit 7: interrupt valid bit
  	 */
  	u8 device_status;
  	/*
  	 * bit 7 - 4: number of fingers currently touching pad
  	 * bit 3: valid data check bit
  	 * bit 2: middle mechanism button state if exists
  	 * bit 1: right mechanism button state if exists
  	 * bit 0: left mechanism button state if exists
  	 */
  	u8 finger_btn;
  	/* CYAPA reports up to 5 touches per packet. */
  	struct cyapa_touch touches[5];
  } __packed;
  
  /* The main device structure */
  struct cyapa {
  	enum cyapa_state state;
  
  	struct i2c_client *client;
  	struct input_dev *input;
  	char phys[32];	/* device physical location */
  	int irq;
  	bool irq_wake;  /* irq wake is enabled */
  	bool smbus;
  
  	/* read from query data region. */
  	char product_id[16];
  	u8 btn_capability;
  	u8 gen;
  	int max_abs_x;
  	int max_abs_y;
  	int physical_size_x;
  	int physical_size_y;
  };
  
  static const u8 bl_deactivate[] = { 0x00, 0xff, 0x3b, 0x00, 0x01, 0x02, 0x03,
  		0x04, 0x05, 0x06, 0x07 };
  static const u8 bl_exit[] = { 0x00, 0xff, 0xa5, 0x00, 0x01, 0x02, 0x03, 0x04,
  		0x05, 0x06, 0x07 };
  
  struct cyapa_cmd_len {
  	u8 cmd;
  	u8 len;
  };
  
  #define CYAPA_ADAPTER_FUNC_NONE   0
  #define CYAPA_ADAPTER_FUNC_I2C    1
  #define CYAPA_ADAPTER_FUNC_SMBUS  2
  #define CYAPA_ADAPTER_FUNC_BOTH   3
  
  /*
   * macros for SMBus communication
   */
  #define SMBUS_READ   0x01
  #define SMBUS_WRITE 0x00
  #define SMBUS_ENCODE_IDX(cmd, idx) ((cmd) | (((idx) & 0x03) << 1))
  #define SMBUS_ENCODE_RW(cmd, rw) ((cmd) | ((rw) & 0x01))
  #define SMBUS_BYTE_BLOCK_CMD_MASK 0x80
  #define SMBUS_GROUP_BLOCK_CMD_MASK 0x40
  
   /* for byte read/write command */
  #define CMD_RESET 0
  #define CMD_POWER_MODE 1
  #define CMD_DEV_STATUS 2
  #define SMBUS_BYTE_CMD(cmd) (((cmd) & 0x3f) << 1)
  #define CYAPA_SMBUS_RESET SMBUS_BYTE_CMD(CMD_RESET)
  #define CYAPA_SMBUS_POWER_MODE SMBUS_BYTE_CMD(CMD_POWER_MODE)
  #define CYAPA_SMBUS_DEV_STATUS SMBUS_BYTE_CMD(CMD_DEV_STATUS)
  
   /* for group registers read/write command */
  #define REG_GROUP_DATA 0
  #define REG_GROUP_CMD 2
  #define REG_GROUP_QUERY 3
  #define SMBUS_GROUP_CMD(grp) (0x80 | (((grp) & 0x07) << 3))
  #define CYAPA_SMBUS_GROUP_DATA SMBUS_GROUP_CMD(REG_GROUP_DATA)
  #define CYAPA_SMBUS_GROUP_CMD SMBUS_GROUP_CMD(REG_GROUP_CMD)
  #define CYAPA_SMBUS_GROUP_QUERY SMBUS_GROUP_CMD(REG_GROUP_QUERY)
  
   /* for register block read/write command */
  #define CMD_BL_STATUS 0
  #define CMD_BL_HEAD 1
  #define CMD_BL_CMD 2
  #define CMD_BL_DATA 3
  #define CMD_BL_ALL 4
  #define CMD_BLK_PRODUCT_ID 5
  #define CMD_BLK_HEAD 6
  #define SMBUS_BLOCK_CMD(cmd) (0xc0 | (((cmd) & 0x1f) << 1))
  
  /* register block read/write command in bootloader mode */
  #define CYAPA_SMBUS_BL_STATUS SMBUS_BLOCK_CMD(CMD_BL_STATUS)
  #define CYAPA_SMBUS_BL_HEAD SMBUS_BLOCK_CMD(CMD_BL_HEAD)
  #define CYAPA_SMBUS_BL_CMD SMBUS_BLOCK_CMD(CMD_BL_CMD)
  #define CYAPA_SMBUS_BL_DATA SMBUS_BLOCK_CMD(CMD_BL_DATA)
  #define CYAPA_SMBUS_BL_ALL SMBUS_BLOCK_CMD(CMD_BL_ALL)
  
  /* register block read/write command in operational mode */
  #define CYAPA_SMBUS_BLK_PRODUCT_ID SMBUS_BLOCK_CMD(CMD_BLK_PRODUCT_ID)
  #define CYAPA_SMBUS_BLK_HEAD SMBUS_BLOCK_CMD(CMD_BLK_HEAD)
  
  static const struct cyapa_cmd_len cyapa_i2c_cmds[] = {
  	{ CYAPA_OFFSET_SOFT_RESET, 1 },
  	{ REG_OFFSET_COMMAND_BASE + 1, 1 },
  	{ REG_OFFSET_DATA_BASE, 1 },
  	{ REG_OFFSET_DATA_BASE, sizeof(struct cyapa_reg_data) },
  	{ REG_OFFSET_COMMAND_BASE, 0 },
  	{ REG_OFFSET_QUERY_BASE, QUERY_DATA_SIZE },
  	{ BL_HEAD_OFFSET, 3 },
  	{ BL_HEAD_OFFSET, 16 },
  	{ BL_HEAD_OFFSET, 16 },
  	{ BL_DATA_OFFSET, 16 },
  	{ BL_HEAD_OFFSET, 32 },
  	{ REG_OFFSET_QUERY_BASE, PRODUCT_ID_SIZE },
  	{ REG_OFFSET_DATA_BASE, 32 }
  };
  
  static const struct cyapa_cmd_len cyapa_smbus_cmds[] = {
  	{ CYAPA_SMBUS_RESET, 1 },
  	{ CYAPA_SMBUS_POWER_MODE, 1 },
  	{ CYAPA_SMBUS_DEV_STATUS, 1 },
  	{ CYAPA_SMBUS_GROUP_DATA, sizeof(struct cyapa_reg_data) },
  	{ CYAPA_SMBUS_GROUP_CMD, 2 },
  	{ CYAPA_SMBUS_GROUP_QUERY, QUERY_DATA_SIZE },
  	{ CYAPA_SMBUS_BL_STATUS, 3 },
  	{ CYAPA_SMBUS_BL_HEAD, 16 },
  	{ CYAPA_SMBUS_BL_CMD, 16 },
  	{ CYAPA_SMBUS_BL_DATA, 16 },
  	{ CYAPA_SMBUS_BL_ALL, 32 },
  	{ CYAPA_SMBUS_BLK_PRODUCT_ID, PRODUCT_ID_SIZE },
  	{ CYAPA_SMBUS_BLK_HEAD, 16 },
  };
  
  static ssize_t cyapa_i2c_reg_read_block(struct cyapa *cyapa, u8 reg, size_t len,
  					u8 *values)
  {
  	return i2c_smbus_read_i2c_block_data(cyapa->client, reg, len, values);
  }
  
  static ssize_t cyapa_i2c_reg_write_block(struct cyapa *cyapa, u8 reg,
  					 size_t len, const u8 *values)
  {
  	return i2c_smbus_write_i2c_block_data(cyapa->client, reg, len, values);
  }
  
  /*
   * cyapa_smbus_read_block - perform smbus block read command
   * @cyapa  - private data structure of the driver
   * @cmd    - the properly encoded smbus command
   * @len    - expected length of smbus command result
   * @values - buffer to store smbus command result
   *
   * Returns negative errno, else the number of bytes written.
   *
   * Note:
   * In trackpad device, the memory block allocated for I2C register map
   * is 256 bytes, so the max read block for I2C bus is 256 bytes.
   */
  static ssize_t cyapa_smbus_read_block(struct cyapa *cyapa, u8 cmd, size_t len,
  				      u8 *values)
  {
  	ssize_t ret;
  	u8 index;
  	u8 smbus_cmd;
  	u8 *buf;
  	struct i2c_client *client = cyapa->client;
  
  	if (!(SMBUS_BYTE_BLOCK_CMD_MASK & cmd))
  		return -EINVAL;
  
  	if (SMBUS_GROUP_BLOCK_CMD_MASK & cmd) {
  		/* read specific block registers command. */
  		smbus_cmd = SMBUS_ENCODE_RW(cmd, SMBUS_READ);
  		ret = i2c_smbus_read_block_data(client, smbus_cmd, values);
  		goto out;
  	}
  
  	ret = 0;
  	for (index = 0; index * I2C_SMBUS_BLOCK_MAX < len; index++) {
  		smbus_cmd = SMBUS_ENCODE_IDX(cmd, index);
  		smbus_cmd = SMBUS_ENCODE_RW(smbus_cmd, SMBUS_READ);
  		buf = values + I2C_SMBUS_BLOCK_MAX * index;
  		ret = i2c_smbus_read_block_data(client, smbus_cmd, buf);
  		if (ret < 0)
  			goto out;
  	}
  
  out:
  	return ret > 0 ? len : ret;
  }
  
  static s32 cyapa_read_byte(struct cyapa *cyapa, u8 cmd_idx)
  {
  	u8 cmd;
  
  	if (cyapa->smbus) {
  		cmd = cyapa_smbus_cmds[cmd_idx].cmd;
  		cmd = SMBUS_ENCODE_RW(cmd, SMBUS_READ);
  	} else {
  		cmd = cyapa_i2c_cmds[cmd_idx].cmd;
  	}
  	return i2c_smbus_read_byte_data(cyapa->client, cmd);
  }
  
  static s32 cyapa_write_byte(struct cyapa *cyapa, u8 cmd_idx, u8 value)
  {
  	u8 cmd;
  
  	if (cyapa->smbus) {
  		cmd = cyapa_smbus_cmds[cmd_idx].cmd;
  		cmd = SMBUS_ENCODE_RW(cmd, SMBUS_WRITE);
  	} else {
  		cmd = cyapa_i2c_cmds[cmd_idx].cmd;
  	}
  	return i2c_smbus_write_byte_data(cyapa->client, cmd, value);
  }
  
  static ssize_t cyapa_read_block(struct cyapa *cyapa, u8 cmd_idx, u8 *values)
  {
  	u8 cmd;
  	size_t len;
  
  	if (cyapa->smbus) {
  		cmd = cyapa_smbus_cmds[cmd_idx].cmd;
  		len = cyapa_smbus_cmds[cmd_idx].len;
  		return cyapa_smbus_read_block(cyapa, cmd, len, values);
  	} else {
  		cmd = cyapa_i2c_cmds[cmd_idx].cmd;
  		len = cyapa_i2c_cmds[cmd_idx].len;
  		return cyapa_i2c_reg_read_block(cyapa, cmd, len, values);
  	}
  }
  
  /*
   * Query device for its current operating state.
   *
   */
  static int cyapa_get_state(struct cyapa *cyapa)
  {
  	int ret;
  	u8 status[BL_STATUS_SIZE];
  
  	cyapa->state = CYAPA_STATE_NO_DEVICE;
  
  	/*
  	 * Get trackpad status by reading 3 registers starting from 0.
  	 * If the device is in the bootloader, this will be BL_HEAD.
  	 * If the device is in operation mode, this will be the DATA regs.
  	 *
  	 */
  	ret = cyapa_i2c_reg_read_block(cyapa, BL_HEAD_OFFSET, BL_STATUS_SIZE,
  				       status);
  
  	/*
  	 * On smbus systems in OP mode, the i2c_reg_read will fail with
  	 * -ETIMEDOUT.  In this case, try again using the smbus equivalent
  	 * command.  This should return a BL_HEAD indicating CYAPA_STATE_OP.
  	 */
  	if (cyapa->smbus && (ret == -ETIMEDOUT || ret == -ENXIO))
  		ret = cyapa_read_block(cyapa, CYAPA_CMD_BL_STATUS, status);
  
  	if (ret != BL_STATUS_SIZE)
  		goto error;
  
  	if ((status[REG_OP_STATUS] & OP_STATUS_SRC) == OP_STATUS_SRC) {
  		switch (status[REG_OP_STATUS] & OP_STATUS_DEV) {
  		case CYAPA_DEV_NORMAL:
  		case CYAPA_DEV_BUSY:
  			cyapa->state = CYAPA_STATE_OP;
  			break;
  		default:
  			ret = -EAGAIN;
  			goto error;
  		}
  	} else {
  		if (status[REG_BL_STATUS] & BL_STATUS_BUSY)
  			cyapa->state = CYAPA_STATE_BL_BUSY;
  		else if (status[REG_BL_ERROR] & BL_ERROR_BOOTLOADING)
  			cyapa->state = CYAPA_STATE_BL_ACTIVE;
  		else
  			cyapa->state = CYAPA_STATE_BL_IDLE;
  	}
  
  	return 0;
  error:
  	return (ret < 0) ? ret : -EAGAIN;
  }
  
  /*
   * Poll device for its status in a loop, waiting up to timeout for a response.
   *
   * When the device switches state, it usually takes ~300 ms.
   * However, when running a new firmware image, the device must calibrate its
   * sensors, which can take as long as 2 seconds.
   *
   * Note: The timeout has granularity of the polling rate, which is 100 ms.
   *
   * Returns:
   *   0 when the device eventually responds with a valid non-busy state.
   *   -ETIMEDOUT if device never responds (too many -EAGAIN)
   *   < 0    other errors
   */
  static int cyapa_poll_state(struct cyapa *cyapa, unsigned int timeout)
  {
  	int ret;
  	int tries = timeout / 100;
  
  	ret = cyapa_get_state(cyapa);
  	while ((ret || cyapa->state >= CYAPA_STATE_BL_BUSY) && tries--) {
  		msleep(100);
  		ret = cyapa_get_state(cyapa);
  	}
  	return (ret == -EAGAIN || ret == -ETIMEDOUT) ? -ETIMEDOUT : ret;
  }
  
  static int cyapa_bl_deactivate(struct cyapa *cyapa)
  {
  	int ret;
  
  	ret = cyapa_i2c_reg_write_block(cyapa, 0, sizeof(bl_deactivate),
  					bl_deactivate);
  	if (ret < 0)
  		return ret;
  
  	/* wait for bootloader to switch to idle state; should take < 100ms */
  	msleep(100);
  	ret = cyapa_poll_state(cyapa, 500);
  	if (ret < 0)
  		return ret;
  	if (cyapa->state != CYAPA_STATE_BL_IDLE)
  		return -EAGAIN;
  	return 0;
  }
  
  /*
   * Exit bootloader
   *
   * Send bl_exit command, then wait 50 - 100 ms to let device transition to
   * operational mode.  If this is the first time the device's firmware is
   * running, it can take up to 2 seconds to calibrate its sensors.  So, poll
   * the device's new state for up to 2 seconds.
   *
   * Returns:
   *   -EIO    failure while reading from device
   *   -EAGAIN device is stuck in bootloader, b/c it has invalid firmware
   *   0       device is supported and in operational mode
   */
  static int cyapa_bl_exit(struct cyapa *cyapa)
  {
  	int ret;
  
  	ret = cyapa_i2c_reg_write_block(cyapa, 0, sizeof(bl_exit), bl_exit);
  	if (ret < 0)
  		return ret;
  
  	/*
  	 * Wait for bootloader to exit, and operation mode to start.
  	 * Normally, this takes at least 50 ms.
  	 */
  	usleep_range(50000, 100000);
  	/*
  	 * In addition, when a device boots for the first time after being
  	 * updated to new firmware, it must first calibrate its sensors, which
  	 * can take up to an additional 2 seconds.
  	 */
  	ret = cyapa_poll_state(cyapa, 2000);
  	if (ret < 0)
  		return ret;
  	if (cyapa->state != CYAPA_STATE_OP)
  		return -EAGAIN;
  
  	return 0;
  }
  
  /*
   * Set device power mode
   *
   */
  static int cyapa_set_power_mode(struct cyapa *cyapa, u8 power_mode)
  {
  	struct device *dev = &cyapa->client->dev;
  	int ret;
  	u8 power;
  
  	if (cyapa->state != CYAPA_STATE_OP)
  		return 0;
  
  	ret = cyapa_read_byte(cyapa, CYAPA_CMD_POWER_MODE);
  	if (ret < 0)
  		return ret;
  
  	power = ret & ~PWR_MODE_MASK;
  	power |= power_mode & PWR_MODE_MASK;
  	ret = cyapa_write_byte(cyapa, CYAPA_CMD_POWER_MODE, power);
  	if (ret < 0)
  		dev_err(dev, "failed to set power_mode 0x%02x err = %d
  ",
  			power_mode, ret);
  	return ret;
  }
  
  static int cyapa_get_query_data(struct cyapa *cyapa)
  {
  	u8 query_data[QUERY_DATA_SIZE];
  	int ret;
  
  	if (cyapa->state != CYAPA_STATE_OP)
  		return -EBUSY;
  
  	ret = cyapa_read_block(cyapa, CYAPA_CMD_GROUP_QUERY, query_data);
  	if (ret < 0)
  		return ret;
  	if (ret != QUERY_DATA_SIZE)
  		return -EIO;
  
  	memcpy(&cyapa->product_id[0], &query_data[0], 5);
  	cyapa->product_id[5] = '-';
  	memcpy(&cyapa->product_id[6], &query_data[5], 6);
  	cyapa->product_id[12] = '-';
  	memcpy(&cyapa->product_id[13], &query_data[11], 2);
  	cyapa->product_id[15] = '\0';
  
  	cyapa->btn_capability = query_data[19] & CAPABILITY_BTN_MASK;
  
  	cyapa->gen = query_data[20] & 0x0f;
  
  	cyapa->max_abs_x = ((query_data[21] & 0xf0) << 4) | query_data[22];
  	cyapa->max_abs_y = ((query_data[21] & 0x0f) << 8) | query_data[23];
  
  	cyapa->physical_size_x =
  		((query_data[24] & 0xf0) << 4) | query_data[25];
  	cyapa->physical_size_y =
  		((query_data[24] & 0x0f) << 8) | query_data[26];
  
  	return 0;
  }
  
  /*
   * Check if device is operational.
   *
   * An operational device is responding, has exited bootloader, and has
   * firmware supported by this driver.
   *
   * Returns:
   *   -EBUSY  no device or in bootloader
   *   -EIO    failure while reading from device
   *   -EAGAIN device is still in bootloader
   *           if ->state = CYAPA_STATE_BL_IDLE, device has invalid firmware
   *   -EINVAL device is in operational mode, but not supported by this driver
   *   0       device is supported
   */
  static int cyapa_check_is_operational(struct cyapa *cyapa)
  {
  	struct device *dev = &cyapa->client->dev;
  	static const char unique_str[] = "CYTRA";
  	int ret;
  
  	ret = cyapa_poll_state(cyapa, 2000);
  	if (ret < 0)
  		return ret;
  	switch (cyapa->state) {
  	case CYAPA_STATE_BL_ACTIVE:
  		ret = cyapa_bl_deactivate(cyapa);
  		if (ret)
  			return ret;
  
  	/* Fallthrough state */
  	case CYAPA_STATE_BL_IDLE:
  		ret = cyapa_bl_exit(cyapa);
  		if (ret)
  			return ret;
  
  	/* Fallthrough state */
  	case CYAPA_STATE_OP:
  		ret = cyapa_get_query_data(cyapa);
  		if (ret < 0)
  			return ret;
  
  		/* only support firmware protocol gen3 */
  		if (cyapa->gen != CYAPA_GEN3) {
  			dev_err(dev, "unsupported protocol version (%d)",
  				cyapa->gen);
  			return -EINVAL;
  		}
  
  		/* only support product ID starting with CYTRA */
  		if (memcmp(cyapa->product_id, unique_str,
  			   sizeof(unique_str) - 1) != 0) {
  			dev_err(dev, "unsupported product ID (%s)
  ",
  				cyapa->product_id);
  			return -EINVAL;
  		}
  		return 0;
  
  	default:
  		return -EIO;
  	}
  	return 0;
  }
  
  static irqreturn_t cyapa_irq(int irq, void *dev_id)
  {
  	struct cyapa *cyapa = dev_id;
  	struct device *dev = &cyapa->client->dev;
  	struct input_dev *input = cyapa->input;
  	struct cyapa_reg_data data;
  	int i;
  	int ret;
  	int num_fingers;
  
  	if (device_may_wakeup(dev))
  		pm_wakeup_event(dev, 0);
  
  	ret = cyapa_read_block(cyapa, CYAPA_CMD_GROUP_DATA, (u8 *)&data);
  	if (ret != sizeof(data))
  		goto out;
  
  	if ((data.device_status & OP_STATUS_SRC) != OP_STATUS_SRC ||
  	    (data.device_status & OP_STATUS_DEV) != CYAPA_DEV_NORMAL ||
  	    (data.finger_btn & OP_DATA_VALID) != OP_DATA_VALID) {
  		goto out;
  	}
  
  	num_fingers = (data.finger_btn >> 4) & 0x0f;
  	for (i = 0; i < num_fingers; i++) {
  		const struct cyapa_touch *touch = &data.touches[i];
  		/* Note: touch->id range is 1 to 15; slots are 0 to 14. */
  		int slot = touch->id - 1;
  
  		input_mt_slot(input, slot);
  		input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
  		input_report_abs(input, ABS_MT_POSITION_X,
  				 ((touch->xy_hi & 0xf0) << 4) | touch->x_lo);
  		input_report_abs(input, ABS_MT_POSITION_Y,
  				 ((touch->xy_hi & 0x0f) << 8) | touch->y_lo);
  		input_report_abs(input, ABS_MT_PRESSURE, touch->pressure);
  	}
  
  	input_mt_sync_frame(input);
  
  	if (cyapa->btn_capability & CAPABILITY_LEFT_BTN_MASK)
  		input_report_key(input, BTN_LEFT,
  				 data.finger_btn & OP_DATA_LEFT_BTN);
  
  	if (cyapa->btn_capability & CAPABILITY_MIDDLE_BTN_MASK)
  		input_report_key(input, BTN_MIDDLE,
  				 data.finger_btn & OP_DATA_MIDDLE_BTN);
  
  	if (cyapa->btn_capability & CAPABILITY_RIGHT_BTN_MASK)
  		input_report_key(input, BTN_RIGHT,
  				 data.finger_btn & OP_DATA_RIGHT_BTN);
  
  	input_sync(input);
  
  out:
  	return IRQ_HANDLED;
  }
  
  static u8 cyapa_check_adapter_functionality(struct i2c_client *client)
  {
  	u8 ret = CYAPA_ADAPTER_FUNC_NONE;
  
  	if (i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
  		ret |= CYAPA_ADAPTER_FUNC_I2C;
  	if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
  				     I2C_FUNC_SMBUS_BLOCK_DATA |
  				     I2C_FUNC_SMBUS_I2C_BLOCK))
  		ret |= CYAPA_ADAPTER_FUNC_SMBUS;
  	return ret;
  }
  
  static int cyapa_create_input_dev(struct cyapa *cyapa)
  {
  	struct device *dev = &cyapa->client->dev;
  	int ret;
  	struct input_dev *input;
  
  	if (!cyapa->physical_size_x || !cyapa->physical_size_y)
  		return -EINVAL;
  
  	input = cyapa->input = input_allocate_device();
  	if (!input) {
  		dev_err(dev, "allocate memory for input device failed
  ");
  		return -ENOMEM;
  	}
  
  	input->name = CYAPA_NAME;
  	input->phys = cyapa->phys;
  	input->id.bustype = BUS_I2C;
  	input->id.version = 1;
  	input->id.product = 0;  /* means any product in eventcomm. */
  	input->dev.parent = &cyapa->client->dev;
  
  	input_set_drvdata(input, cyapa);
  
  	__set_bit(EV_ABS, input->evbit);
  
  	/* finger position */
  	input_set_abs_params(input, ABS_MT_POSITION_X, 0, cyapa->max_abs_x, 0,
  			     0);
  	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, cyapa->max_abs_y, 0,
  			     0);
  	input_set_abs_params(input, ABS_MT_PRESSURE, 0, 255, 0, 0);
  
  	input_abs_set_res(input, ABS_MT_POSITION_X,
  			  cyapa->max_abs_x / cyapa->physical_size_x);
  	input_abs_set_res(input, ABS_MT_POSITION_Y,
  			  cyapa->max_abs_y / cyapa->physical_size_y);
  
  	if (cyapa->btn_capability & CAPABILITY_LEFT_BTN_MASK)
  		__set_bit(BTN_LEFT, input->keybit);
  	if (cyapa->btn_capability & CAPABILITY_MIDDLE_BTN_MASK)
  		__set_bit(BTN_MIDDLE, input->keybit);
  	if (cyapa->btn_capability & CAPABILITY_RIGHT_BTN_MASK)
  		__set_bit(BTN_RIGHT, input->keybit);
  
  	if (cyapa->btn_capability == CAPABILITY_LEFT_BTN_MASK)
  		__set_bit(INPUT_PROP_BUTTONPAD, input->propbit);
  
  	/* handle pointer emulation and unused slots in core */
  	ret = input_mt_init_slots(input, CYAPA_MAX_MT_SLOTS,
  				  INPUT_MT_POINTER | INPUT_MT_DROP_UNUSED);
  	if (ret) {
  		dev_err(dev, "allocate memory for MT slots failed, %d
  ", ret);
  		goto err_free_device;
  	}
  
  	/* Register the device in input subsystem */
  	ret = input_register_device(input);
  	if (ret) {
  		dev_err(dev, "input device register failed, %d
  ", ret);
  		goto err_free_device;
  	}
  	return 0;
  
  err_free_device:
  	input_free_device(input);
  	cyapa->input = NULL;
  	return ret;
  }
  
  static int cyapa_probe(struct i2c_client *client,
  		       const struct i2c_device_id *dev_id)
  {
  	int ret;
  	u8 adapter_func;
  	struct cyapa *cyapa;
  	struct device *dev = &client->dev;
  
  	adapter_func = cyapa_check_adapter_functionality(client);
  	if (adapter_func == CYAPA_ADAPTER_FUNC_NONE) {
  		dev_err(dev, "not a supported I2C/SMBus adapter
  ");
  		return -EIO;
  	}
  
  	cyapa = kzalloc(sizeof(struct cyapa), GFP_KERNEL);
  	if (!cyapa) {
  		dev_err(dev, "allocate memory for cyapa failed
  ");
  		return -ENOMEM;
  	}
  
  	cyapa->gen = CYAPA_GEN3;
  	cyapa->client = client;
  	i2c_set_clientdata(client, cyapa);
  	sprintf(cyapa->phys, "i2c-%d-%04x/input0", client->adapter->nr,
  		client->addr);
  
  	/* i2c isn't supported, use smbus */
  	if (adapter_func == CYAPA_ADAPTER_FUNC_SMBUS)
  		cyapa->smbus = true;
  	cyapa->state = CYAPA_STATE_NO_DEVICE;
  	ret = cyapa_check_is_operational(cyapa);
  	if (ret) {
  		dev_err(dev, "device not operational, %d
  ", ret);
  		goto err_mem_free;
  	}
  
  	ret = cyapa_create_input_dev(cyapa);
  	if (ret) {
  		dev_err(dev, "create input_dev instance failed, %d
  ", ret);
  		goto err_mem_free;
  	}
  
  	ret = cyapa_set_power_mode(cyapa, PWR_MODE_FULL_ACTIVE);
  	if (ret) {
  		dev_err(dev, "set active power failed, %d
  ", ret);
  		goto err_unregister_device;
  	}
  
  	cyapa->irq = client->irq;
  	ret = request_threaded_irq(cyapa->irq,
  				   NULL,
  				   cyapa_irq,
  				   IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
  				   "cyapa",
  				   cyapa);
  	if (ret) {
  		dev_err(dev, "IRQ request failed: %d
  , ", ret);
  		goto err_unregister_device;
  	}
  
  	return 0;
  
  err_unregister_device:
  	input_unregister_device(cyapa->input);
  err_mem_free:
  	kfree(cyapa);
  
  	return ret;
  }
  
  static int cyapa_remove(struct i2c_client *client)
  {
  	struct cyapa *cyapa = i2c_get_clientdata(client);
  
  	free_irq(cyapa->irq, cyapa);
  	input_unregister_device(cyapa->input);
  	cyapa_set_power_mode(cyapa, PWR_MODE_OFF);
  	kfree(cyapa);
  
  	return 0;
  }
  
  #ifdef CONFIG_PM_SLEEP
  static int cyapa_suspend(struct device *dev)
  {
  	int ret;
  	u8 power_mode;
  	struct cyapa *cyapa = dev_get_drvdata(dev);
  
  	disable_irq(cyapa->irq);
  
  	/*
  	 * Set trackpad device to idle mode if wakeup is allowed,
  	 * otherwise turn off.
  	 */
  	power_mode = device_may_wakeup(dev) ? PWR_MODE_IDLE
  					    : PWR_MODE_OFF;
  	ret = cyapa_set_power_mode(cyapa, power_mode);
  	if (ret < 0)
  		dev_err(dev, "set power mode failed, %d
  ", ret);
  
  	if (device_may_wakeup(dev))
  		cyapa->irq_wake = (enable_irq_wake(cyapa->irq) == 0);
  	return 0;
  }
  
  static int cyapa_resume(struct device *dev)
  {
  	int ret;
  	struct cyapa *cyapa = dev_get_drvdata(dev);
  
  	if (device_may_wakeup(dev) && cyapa->irq_wake)
  		disable_irq_wake(cyapa->irq);
  
  	ret = cyapa_set_power_mode(cyapa, PWR_MODE_FULL_ACTIVE);
  	if (ret)
  		dev_warn(dev, "resume active power failed, %d
  ", ret);
  
  	enable_irq(cyapa->irq);
  	return 0;
  }
  #endif /* CONFIG_PM_SLEEP */
  
  static SIMPLE_DEV_PM_OPS(cyapa_pm_ops, cyapa_suspend, cyapa_resume);
  
  static const struct i2c_device_id cyapa_id_table[] = {
  	{ "cyapa", 0 },
  	{ },
  };
  MODULE_DEVICE_TABLE(i2c, cyapa_id_table);
  
  static struct i2c_driver cyapa_driver = {
  	.driver = {
  		.name = "cyapa",
  		.owner = THIS_MODULE,
  		.pm = &cyapa_pm_ops,
  	},
  
  	.probe = cyapa_probe,
  	.remove = cyapa_remove,
  	.id_table = cyapa_id_table,
  };
  
  module_i2c_driver(cyapa_driver);
  
  MODULE_DESCRIPTION("Cypress APA I2C Trackpad Driver");
  MODULE_AUTHOR("Dudley Du <dudl@cypress.com>");
  MODULE_LICENSE("GPL");