/*
   * Elan I2C/SMBus Touchpad driver - I2C interface
   *
   * Copyright (c) 2013 ELAN Microelectronics Corp.
   *
   * Author: 林政維 (Duson Lin) <dusonlin@emc.com.tw>
   *
   * Based on cyapa driver:
   * copyright (c) 2011-2012 Cypress Semiconductor, Inc.
   * copyright (c) 2011-2012 Google, Inc.
   *
   * 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/completion.h>
  #include <linux/delay.h>
  #include <linux/i2c.h>
  #include <linux/interrupt.h>
  #include <linux/jiffies.h>
  #include <linux/kernel.h>
  #include <linux/sched.h>
  #include <asm/unaligned.h>
  
  #include "elan_i2c.h"
  
  /* Elan i2c commands */
  #define ETP_I2C_RESET			0x0100
  #define ETP_I2C_WAKE_UP			0x0800
  #define ETP_I2C_SLEEP			0x0801
  #define ETP_I2C_DESC_CMD		0x0001
  #define ETP_I2C_REPORT_DESC_CMD		0x0002
  #define ETP_I2C_STAND_CMD		0x0005
  #define ETP_I2C_UNIQUEID_CMD		0x0101
  #define ETP_I2C_FW_VERSION_CMD		0x0102
  #define ETP_I2C_SM_VERSION_CMD		0x0103
  #define ETP_I2C_XY_TRACENUM_CMD		0x0105
  #define ETP_I2C_MAX_X_AXIS_CMD		0x0106
  #define ETP_I2C_MAX_Y_AXIS_CMD		0x0107
  #define ETP_I2C_RESOLUTION_CMD		0x0108
  #define ETP_I2C_PRESSURE_CMD		0x010A
  #define ETP_I2C_IAP_VERSION_CMD		0x0110
  #define ETP_I2C_SET_CMD			0x0300
  #define ETP_I2C_POWER_CMD		0x0307
  #define ETP_I2C_FW_CHECKSUM_CMD		0x030F
  #define ETP_I2C_IAP_CTRL_CMD		0x0310
  #define ETP_I2C_IAP_CMD			0x0311
  #define ETP_I2C_IAP_RESET_CMD		0x0314
  #define ETP_I2C_IAP_CHECKSUM_CMD	0x0315
  #define ETP_I2C_CALIBRATE_CMD		0x0316
  #define ETP_I2C_MAX_BASELINE_CMD	0x0317
  #define ETP_I2C_MIN_BASELINE_CMD	0x0318
  
  #define ETP_I2C_REPORT_LEN		34
  #define ETP_I2C_DESC_LENGTH		30
  #define ETP_I2C_REPORT_DESC_LENGTH	158
  #define ETP_I2C_INF_LENGTH		2
  #define ETP_I2C_IAP_PASSWORD		0x1EA5
  #define ETP_I2C_IAP_RESET		0xF0F0
  #define ETP_I2C_MAIN_MODE_ON		(1 << 9)
  #define ETP_I2C_IAP_REG_L		0x01
  #define ETP_I2C_IAP_REG_H		0x06
  
  static int elan_i2c_read_block(struct i2c_client *client,
  			       u16 reg, u8 *val, u16 len)
  {
  	__le16 buf[] = {
  		cpu_to_le16(reg),
  	};
  	struct i2c_msg msgs[] = {
  		{
  			.addr = client->addr,
  			.flags = client->flags & I2C_M_TEN,
  			.len = sizeof(buf),
  			.buf = (u8 *)buf,
  		},
  		{
  			.addr = client->addr,
  			.flags = (client->flags & I2C_M_TEN) | I2C_M_RD,
  			.len = len,
  			.buf = val,
  		}
  	};
  	int ret;
  
  	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
  	return ret == ARRAY_SIZE(msgs) ? 0 : (ret < 0 ? ret : -EIO);
  }
  
  static int elan_i2c_read_cmd(struct i2c_client *client, u16 reg, u8 *val)
  {
  	int retval;
  
  	retval = elan_i2c_read_block(client, reg, val, ETP_I2C_INF_LENGTH);
  	if (retval < 0) {
  		dev_err(&client->dev, "reading cmd (0x%04x) fail.
  ", reg);
  		return retval;
  	}
  
  	return 0;
  }
  
  static int elan_i2c_write_cmd(struct i2c_client *client, u16 reg, u16 cmd)
  {
  	__le16 buf[] = {
  		cpu_to_le16(reg),
  		cpu_to_le16(cmd),
  	};
  	struct i2c_msg msg = {
  		.addr = client->addr,
  		.flags = client->flags & I2C_M_TEN,
  		.len = sizeof(buf),
  		.buf = (u8 *)buf,
  	};
  	int ret;
  
  	ret = i2c_transfer(client->adapter, &msg, 1);
  	if (ret != 1) {
  		if (ret >= 0)
  			ret = -EIO;
  		dev_err(&client->dev, "writing cmd (0x%04x) failed: %d
  ",
  			reg, ret);
  		return ret;
  	}
  
  	return 0;
  }
  
  static int elan_i2c_initialize(struct i2c_client *client)
  {
  	struct device *dev = &client->dev;
  	int error;
  	u8 val[256];
  
  	error = elan_i2c_write_cmd(client, ETP_I2C_STAND_CMD, ETP_I2C_RESET);
  	if (error) {
  		dev_err(dev, "device reset failed: %d
  ", error);
  		return error;
  	}
  
  	/* Wait for the device to reset */
  	msleep(100);
  
  	/* get reset acknowledgement 0000 */
  	error = i2c_master_recv(client, val, ETP_I2C_INF_LENGTH);
  	if (error < 0) {
  		dev_err(dev, "failed to read reset response: %d
  ", error);
  		return error;
  	}
  
  	error = elan_i2c_read_block(client, ETP_I2C_DESC_CMD,
  				    val, ETP_I2C_DESC_LENGTH);
  	if (error) {
  		dev_err(dev, "cannot get device descriptor: %d
  ", error);
  		return error;
  	}
  
  	error = elan_i2c_read_block(client, ETP_I2C_REPORT_DESC_CMD,
  				    val, ETP_I2C_REPORT_DESC_LENGTH);
  	if (error) {
  		dev_err(dev, "fetching report descriptor failed.: %d
  ", error);
  		return error;
  	}
  
  	return 0;
  }
  
  static int elan_i2c_sleep_control(struct i2c_client *client, bool sleep)
  {
  	return elan_i2c_write_cmd(client, ETP_I2C_STAND_CMD,
  				  sleep ? ETP_I2C_SLEEP : ETP_I2C_WAKE_UP);
  }
  
  static int elan_i2c_power_control(struct i2c_client *client, bool enable)
  {
  	u8 val[2];
  	u16 reg;
  	int error;
  
  	error = elan_i2c_read_cmd(client, ETP_I2C_POWER_CMD, val);
  	if (error) {
  		dev_err(&client->dev,
  			"failed to read current power state: %d
  ",
  			error);
  		return error;
  	}
  
  	reg = le16_to_cpup((__le16 *)val);
  	if (enable)
  		reg &= ~ETP_DISABLE_POWER;
  	else
  		reg |= ETP_DISABLE_POWER;
  
  	error = elan_i2c_write_cmd(client, ETP_I2C_POWER_CMD, reg);
  	if (error) {
  		dev_err(&client->dev,
  			"failed to write current power state: %d
  ",
  			error);
  		return error;
  	}
  
  	return 0;
  }
  
  static int elan_i2c_set_mode(struct i2c_client *client, u8 mode)
  {
  	return elan_i2c_write_cmd(client, ETP_I2C_SET_CMD, mode);
  }
  
  
  static int elan_i2c_calibrate(struct i2c_client *client)
  {
  	return elan_i2c_write_cmd(client, ETP_I2C_CALIBRATE_CMD, 1);
  }
  
  static int elan_i2c_calibrate_result(struct i2c_client *client, u8 *val)
  {
  	return elan_i2c_read_block(client, ETP_I2C_CALIBRATE_CMD, val, 1);
  }
  
  static int elan_i2c_get_baseline_data(struct i2c_client *client,
  				      bool max_baseline, u8 *value)
  {
  	int error;
  	u8 val[3];
  
  	error = elan_i2c_read_cmd(client,
  				  max_baseline ? ETP_I2C_MAX_BASELINE_CMD :
  						 ETP_I2C_MIN_BASELINE_CMD,
  				  val);
  	if (error)
  		return error;
  
  	*value = le16_to_cpup((__le16 *)val);
  
  	return 0;
  }
  
  static int elan_i2c_get_version(struct i2c_client *client,
  				bool iap, u8 *version)
  {
  	int error;
  	u8 val[3];
  
  	error = elan_i2c_read_cmd(client,
  				  iap ? ETP_I2C_IAP_VERSION_CMD :
  					ETP_I2C_FW_VERSION_CMD,
  				  val);
  	if (error) {
  		dev_err(&client->dev, "failed to get %s version: %d
  ",
  			iap ? "IAP" : "FW", error);
  		return error;
  	}
  
  	*version = val[0];
  	return 0;
  }
  
  static int elan_i2c_get_sm_version(struct i2c_client *client,
  				   u8 *ic_type, u8 *version)
  {
  	int error;
  	u8 val[3];
  
  	error = elan_i2c_read_cmd(client, ETP_I2C_SM_VERSION_CMD, val);
  	if (error) {
  		dev_err(&client->dev, "failed to get SM version: %d
  ", error);
  		return error;
  	}
  
  	*version = val[0];
  	*ic_type = val[1];
  	return 0;
  }
  
  static int elan_i2c_get_product_id(struct i2c_client *client, u16 *id)
  {
  	int error;
  	u8 val[3];
  
  	error = elan_i2c_read_cmd(client, ETP_I2C_UNIQUEID_CMD, val);
  	if (error) {
  		dev_err(&client->dev, "failed to get product ID: %d
  ", error);
  		return error;
  	}
  
  	*id = le16_to_cpup((__le16 *)val);
  	return 0;
  }
  
  static int elan_i2c_get_checksum(struct i2c_client *client,
  				 bool iap, u16 *csum)
  {
  	int error;
  	u8 val[3];
  
  	error = elan_i2c_read_cmd(client,
  				  iap ? ETP_I2C_IAP_CHECKSUM_CMD :
  					ETP_I2C_FW_CHECKSUM_CMD,
  				  val);
  	if (error) {
  		dev_err(&client->dev, "failed to get %s checksum: %d
  ",
  			iap ? "IAP" : "FW", error);
  		return error;
  	}
  
  	*csum = le16_to_cpup((__le16 *)val);
  	return 0;
  }
  
  static int elan_i2c_get_max(struct i2c_client *client,
  			    unsigned int *max_x, unsigned int *max_y)
  {
  	int error;
  	u8 val[3];
  
  	error = elan_i2c_read_cmd(client, ETP_I2C_MAX_X_AXIS_CMD, val);
  	if (error) {
  		dev_err(&client->dev, "failed to get X dimension: %d
  ", error);
  		return error;
  	}
  
  	*max_x = le16_to_cpup((__le16 *)val) & 0x0fff;
  
  	error = elan_i2c_read_cmd(client, ETP_I2C_MAX_Y_AXIS_CMD, val);
  	if (error) {
  		dev_err(&client->dev, "failed to get Y dimension: %d
  ", error);
  		return error;
  	}
  
  	*max_y = le16_to_cpup((__le16 *)val) & 0x0fff;
  
  	return 0;
  }
  
  static int elan_i2c_get_resolution(struct i2c_client *client,
  				   u8 *hw_res_x, u8 *hw_res_y)
  {
  	int error;
  	u8 val[3];
  
  	error = elan_i2c_read_cmd(client, ETP_I2C_RESOLUTION_CMD, val);
  	if (error) {
  		dev_err(&client->dev, "failed to get resolution: %d
  ", error);
  		return error;
  	}
  
  	*hw_res_x = val[0];
  	*hw_res_y = val[1];
  
  	return 0;
  }
  
  static int elan_i2c_get_num_traces(struct i2c_client *client,
  				   unsigned int *x_traces,
  				   unsigned int *y_traces)
  {
  	int error;
  	u8 val[3];
  
  	error = elan_i2c_read_cmd(client, ETP_I2C_XY_TRACENUM_CMD, val);
  	if (error) {
  		dev_err(&client->dev, "failed to get trace info: %d
  ", error);
  		return error;
  	}
  
  	*x_traces = val[0];
  	*y_traces = val[1];
  
  	return 0;
  }
  
  static int elan_i2c_get_pressure_adjustment(struct i2c_client *client,
  					    int *adjustment)
  {
  	int error;
  	u8 val[3];
  
  	error = elan_i2c_read_cmd(client, ETP_I2C_PRESSURE_CMD, val);
  	if (error) {
  		dev_err(&client->dev, "failed to get pressure format: %d
  ",
  			error);
  		return error;
  	}
  
  	if ((val[0] >> 4) & 0x1)
  		*adjustment = 0;
  	else
  		*adjustment = ETP_PRESSURE_OFFSET;
  
  	return 0;
  }
  
  static int elan_i2c_iap_get_mode(struct i2c_client *client, enum tp_mode *mode)
  {
  	int error;
  	u16 constant;
  	u8 val[3];
  
  	error = elan_i2c_read_cmd(client, ETP_I2C_IAP_CTRL_CMD, val);
  	if (error) {
  		dev_err(&client->dev,
  			"failed to read iap control register: %d
  ",
  			error);
  		return error;
  	}
  
  	constant = le16_to_cpup((__le16 *)val);
  	dev_dbg(&client->dev, "iap control reg: 0x%04x.
  ", constant);
  
  	*mode = (constant & ETP_I2C_MAIN_MODE_ON) ? MAIN_MODE : IAP_MODE;
  
  	return 0;
  }
  
  static int elan_i2c_iap_reset(struct i2c_client *client)
  {
  	int error;
  
  	error = elan_i2c_write_cmd(client, ETP_I2C_IAP_RESET_CMD,
  				   ETP_I2C_IAP_RESET);
  	if (error) {
  		dev_err(&client->dev, "cannot reset IC: %d
  ", error);
  		return error;
  	}
  
  	return 0;
  }
  
  static int elan_i2c_set_flash_key(struct i2c_client *client)
  {
  	int error;
  
  	error = elan_i2c_write_cmd(client, ETP_I2C_IAP_CMD,
  				   ETP_I2C_IAP_PASSWORD);
  	if (error) {
  		dev_err(&client->dev, "cannot set flash key: %d
  ", error);
  		return error;
  	}
  
  	return 0;
  }
  
  static int elan_i2c_prepare_fw_update(struct i2c_client *client)
  {
  	struct device *dev = &client->dev;
  	int error;
  	enum tp_mode mode;
  	u8 val[3];
  	u16 password;
  
  	/* Get FW in which mode	(IAP_MODE/MAIN_MODE)  */
  	error = elan_i2c_iap_get_mode(client, &mode);
  	if (error)
  		return error;
  
  	if (mode == IAP_MODE) {
  		/* Reset IC */
  		error = elan_i2c_iap_reset(client);
  		if (error)
  			return error;
  
  		msleep(30);
  	}
  
  	/* Set flash key*/
  	error = elan_i2c_set_flash_key(client);
  	if (error)
  		return error;
  
  	/* Wait for F/W IAP initialization */
  	msleep(mode == MAIN_MODE ? 100 : 30);
  
  	/* Check if we are in IAP mode or not */
  	error = elan_i2c_iap_get_mode(client, &mode);
  	if (error)
  		return error;
  
  	if (mode == MAIN_MODE) {
  		dev_err(dev, "wrong mode: %d
  ", mode);
  		return -EIO;
  	}
  
  	/* Set flash key again */
  	error = elan_i2c_set_flash_key(client);
  	if (error)
  		return error;
  
  	/* Wait for F/W IAP initialization */
  	msleep(30);
  
  	/* read back to check we actually enabled successfully. */
  	error = elan_i2c_read_cmd(client, ETP_I2C_IAP_CMD, val);
  	if (error) {
  		dev_err(dev, "cannot read iap password: %d
  ",
  			error);
  		return error;
  	}
  
  	password = le16_to_cpup((__le16 *)val);
  	if (password != ETP_I2C_IAP_PASSWORD) {
  		dev_err(dev, "wrong iap password: 0x%X
  ", password);
  		return -EIO;
  	}
  
  	return 0;
  }
  
  static int elan_i2c_write_fw_block(struct i2c_client *client,
  				   const u8 *page, u16 checksum, int idx)
  {
  	struct device *dev = &client->dev;
  	u8 page_store[ETP_FW_PAGE_SIZE + 4];
  	u8 val[3];
  	u16 result;
  	int ret, error;
  
  	page_store[0] = ETP_I2C_IAP_REG_L;
  	page_store[1] = ETP_I2C_IAP_REG_H;
  	memcpy(&page_store[2], page, ETP_FW_PAGE_SIZE);
  	/* recode checksum at last two bytes */
  	put_unaligned_le16(checksum, &page_store[ETP_FW_PAGE_SIZE + 2]);
  
  	ret = i2c_master_send(client, page_store, sizeof(page_store));
  	if (ret != sizeof(page_store)) {
  		error = ret < 0 ? ret : -EIO;
  		dev_err(dev, "Failed to write page %d: %d
  ", idx, error);
  		return error;
  	}
  
  	/* Wait for F/W to update one page ROM data. */
  	msleep(20);
  
  	error = elan_i2c_read_cmd(client, ETP_I2C_IAP_CTRL_CMD, val);
  	if (error) {
  		dev_err(dev, "Failed to read IAP write result: %d
  ", error);
  		return error;
  	}
  
  	result = le16_to_cpup((__le16 *)val);
  	if (result & (ETP_FW_IAP_PAGE_ERR | ETP_FW_IAP_INTF_ERR)) {
  		dev_err(dev, "IAP reports failed write: %04hx
  ",
  			result);
  		return -EIO;
  	}
  
  	return 0;
  }
  
  static int elan_i2c_finish_fw_update(struct i2c_client *client,
  				     struct completion *completion)
  {
  	struct device *dev = &client->dev;
  	long ret;
  	int error;
  	int len;
  	u8 buffer[ETP_I2C_INF_LENGTH];
  
  	reinit_completion(completion);
  	enable_irq(client->irq);
  
  	error = elan_i2c_write_cmd(client, ETP_I2C_STAND_CMD, ETP_I2C_RESET);
  	if (!error)
  		ret = wait_for_completion_interruptible_timeout(completion,
  							msecs_to_jiffies(300));
  	disable_irq(client->irq);
  
  	if (error) {
  		dev_err(dev, "device reset failed: %d
  ", error);
  		return error;
  	} else if (ret == 0) {
  		dev_err(dev, "timeout waiting for device reset
  ");
  		return -ETIMEDOUT;
  	} else if (ret < 0) {
  		error = ret;
  		dev_err(dev, "error waiting for device reset: %d
  ", error);
  		return error;
  	}
  
  	len = i2c_master_recv(client, buffer, ETP_I2C_INF_LENGTH);
  	if (len != ETP_I2C_INF_LENGTH) {
  		error = len < 0 ? len : -EIO;
  		dev_err(dev, "failed to read INT signal: %d (%d)
  ",
  			error, len);
  		return error;
  	}
  
  	return 0;
  }
  
  static int elan_i2c_get_report(struct i2c_client *client, u8 *report)
  {
  	int len;
  
  	len = i2c_master_recv(client, report, ETP_I2C_REPORT_LEN);
  	if (len < 0) {
  		dev_err(&client->dev, "failed to read report data: %d
  ", len);
  		return len;
  	}
  
  	if (len != ETP_I2C_REPORT_LEN) {
  		dev_err(&client->dev,
  			"wrong report length (%d vs %d expected)
  ",
  			len, ETP_I2C_REPORT_LEN);
  		return -EIO;
  	}
  
  	return 0;
  }
  
  const struct elan_transport_ops elan_i2c_ops = {
  	.initialize		= elan_i2c_initialize,
  	.sleep_control		= elan_i2c_sleep_control,
  	.power_control		= elan_i2c_power_control,
  	.set_mode		= elan_i2c_set_mode,
  
  	.calibrate		= elan_i2c_calibrate,
  	.calibrate_result	= elan_i2c_calibrate_result,
  
  	.get_baseline_data	= elan_i2c_get_baseline_data,
  
  	.get_version		= elan_i2c_get_version,
  	.get_sm_version		= elan_i2c_get_sm_version,
  	.get_product_id		= elan_i2c_get_product_id,
  	.get_checksum		= elan_i2c_get_checksum,
  	.get_pressure_adjustment = elan_i2c_get_pressure_adjustment,
  
  	.get_max		= elan_i2c_get_max,
  	.get_resolution		= elan_i2c_get_resolution,
  	.get_num_traces		= elan_i2c_get_num_traces,
  
  	.iap_get_mode		= elan_i2c_iap_get_mode,
  	.iap_reset		= elan_i2c_iap_reset,
  
  	.prepare_fw_update	= elan_i2c_prepare_fw_update,
  	.write_fw_block		= elan_i2c_write_fw_block,
  	.finish_fw_update	= elan_i2c_finish_fw_update,
  
  	.get_report		= elan_i2c_get_report,
  };