/*
   * amc6821.c - Part of lm_sensors, Linux kernel modules for hardware
   *	       monitoring
   * Copyright (C) 2009 T. Mertelj <tomaz.mertelj@guest.arnes.si>
   *
   * Based on max6650.c:
   * Copyright (C) 2007 Hans J. Koch <hjk@hansjkoch.de>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   */
  
  
  #include <linux/kernel.h>	/* Needed for KERN_INFO */
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/jiffies.h>
  #include <linux/i2c.h>
  #include <linux/hwmon.h>
  #include <linux/hwmon-sysfs.h>
  #include <linux/err.h>
  #include <linux/mutex.h>
  
  
  /*
   * Addresses to scan.
   */
  
  static const unsigned short normal_i2c[] = {0x18, 0x19, 0x1a, 0x2c, 0x2d, 0x2e,
  	0x4c, 0x4d, 0x4e, I2C_CLIENT_END};
  
  
  
  /*
   * Insmod parameters
   */
  
  static int pwminv;	/*Inverted PWM output. */
  module_param(pwminv, int, S_IRUGO);
  
  static int init = 1; /*Power-on initialization.*/
  module_param(init, int, S_IRUGO);
  
  
  enum chips { amc6821 };
  
  #define AMC6821_REG_DEV_ID 0x3D
  #define AMC6821_REG_COMP_ID 0x3E
  #define AMC6821_REG_CONF1 0x00
  #define AMC6821_REG_CONF2 0x01
  #define AMC6821_REG_CONF3 0x3F
  #define AMC6821_REG_CONF4 0x04
  #define AMC6821_REG_STAT1 0x02
  #define AMC6821_REG_STAT2 0x03
  #define AMC6821_REG_TDATA_LOW 0x08
  #define AMC6821_REG_TDATA_HI 0x09
  #define AMC6821_REG_LTEMP_HI 0x0A
  #define AMC6821_REG_RTEMP_HI 0x0B
  #define AMC6821_REG_LTEMP_LIMIT_MIN 0x15
  #define AMC6821_REG_LTEMP_LIMIT_MAX 0x14
  #define AMC6821_REG_RTEMP_LIMIT_MIN 0x19
  #define AMC6821_REG_RTEMP_LIMIT_MAX 0x18
  #define AMC6821_REG_LTEMP_CRIT 0x1B
  #define AMC6821_REG_RTEMP_CRIT 0x1D
  #define AMC6821_REG_PSV_TEMP 0x1C
  #define AMC6821_REG_DCY 0x22
  #define AMC6821_REG_LTEMP_FAN_CTRL 0x24
  #define AMC6821_REG_RTEMP_FAN_CTRL 0x25
  #define AMC6821_REG_DCY_LOW_TEMP 0x21
  
  #define AMC6821_REG_TACH_LLIMITL 0x10
  #define AMC6821_REG_TACH_LLIMITH 0x11
  #define AMC6821_REG_TACH_HLIMITL 0x12
  #define AMC6821_REG_TACH_HLIMITH 0x13
  
  #define AMC6821_CONF1_START 0x01
  #define AMC6821_CONF1_FAN_INT_EN 0x02
  #define AMC6821_CONF1_FANIE 0x04
  #define AMC6821_CONF1_PWMINV 0x08
  #define AMC6821_CONF1_FAN_FAULT_EN 0x10
  #define AMC6821_CONF1_FDRC0 0x20
  #define AMC6821_CONF1_FDRC1 0x40
  #define AMC6821_CONF1_THERMOVIE 0x80
  
  #define AMC6821_CONF2_PWM_EN 0x01
  #define AMC6821_CONF2_TACH_MODE 0x02
  #define AMC6821_CONF2_TACH_EN 0x04
  #define AMC6821_CONF2_RTFIE 0x08
  #define AMC6821_CONF2_LTOIE 0x10
  #define AMC6821_CONF2_RTOIE 0x20
  #define AMC6821_CONF2_PSVIE 0x40
  #define AMC6821_CONF2_RST 0x80
  
  #define AMC6821_CONF3_THERM_FAN_EN 0x80
  #define AMC6821_CONF3_REV_MASK 0x0F
  
  #define AMC6821_CONF4_OVREN 0x10
  #define AMC6821_CONF4_TACH_FAST 0x20
  #define AMC6821_CONF4_PSPR 0x40
  #define AMC6821_CONF4_MODE 0x80
  
  #define AMC6821_STAT1_RPM_ALARM 0x01
  #define AMC6821_STAT1_FANS 0x02
  #define AMC6821_STAT1_RTH 0x04
  #define AMC6821_STAT1_RTL 0x08
  #define AMC6821_STAT1_R_THERM 0x10
  #define AMC6821_STAT1_RTF 0x20
  #define AMC6821_STAT1_LTH 0x40
  #define AMC6821_STAT1_LTL 0x80
  
  #define AMC6821_STAT2_RTC 0x08
  #define AMC6821_STAT2_LTC 0x10
  #define AMC6821_STAT2_LPSV 0x20
  #define AMC6821_STAT2_L_THERM 0x40
  #define AMC6821_STAT2_THERM_IN 0x80
  
  enum {IDX_TEMP1_INPUT = 0, IDX_TEMP1_MIN, IDX_TEMP1_MAX,
  	IDX_TEMP1_CRIT, IDX_TEMP2_INPUT, IDX_TEMP2_MIN,
  	IDX_TEMP2_MAX, IDX_TEMP2_CRIT,
  	TEMP_IDX_LEN, };
  
  static const u8 temp_reg[] = {AMC6821_REG_LTEMP_HI,
  			AMC6821_REG_LTEMP_LIMIT_MIN,
  			AMC6821_REG_LTEMP_LIMIT_MAX,
  			AMC6821_REG_LTEMP_CRIT,
  			AMC6821_REG_RTEMP_HI,
  			AMC6821_REG_RTEMP_LIMIT_MIN,
  			AMC6821_REG_RTEMP_LIMIT_MAX,
  			AMC6821_REG_RTEMP_CRIT, };
  
  enum {IDX_FAN1_INPUT = 0, IDX_FAN1_MIN, IDX_FAN1_MAX,
  	FAN1_IDX_LEN, };
  
  static const u8 fan_reg_low[] = {AMC6821_REG_TDATA_LOW,
  			AMC6821_REG_TACH_LLIMITL,
  			AMC6821_REG_TACH_HLIMITL, };
  
  
  static const u8 fan_reg_hi[] = {AMC6821_REG_TDATA_HI,
  			AMC6821_REG_TACH_LLIMITH,
  			AMC6821_REG_TACH_HLIMITH, };
  
  static int amc6821_probe(
  		struct i2c_client *client,
  		const struct i2c_device_id *id);
  static int amc6821_detect(
  		struct i2c_client *client,
  		struct i2c_board_info *info);
  static int amc6821_init_client(struct i2c_client *client);
  static int amc6821_remove(struct i2c_client *client);
  static struct amc6821_data *amc6821_update_device(struct device *dev);
  
  /*
   * Driver data (common to all clients)
   */
  
  static const struct i2c_device_id amc6821_id[] = {
  	{ "amc6821", amc6821 },
  	{ }
  };
  
  MODULE_DEVICE_TABLE(i2c, amc6821_id);
  
  static struct i2c_driver amc6821_driver = {
  	.class = I2C_CLASS_HWMON,
  	.driver = {
  		.name	= "amc6821",
  	},
  	.probe = amc6821_probe,
  	.remove = amc6821_remove,
  	.id_table = amc6821_id,
  	.detect = amc6821_detect,
  	.address_list = normal_i2c,
  };
  
  
  /*
   * Client data (each client gets its own)
   */
  
  struct amc6821_data {
  	struct device *hwmon_dev;
  	struct mutex update_lock;
  	char valid; /* zero until following fields are valid */
  	unsigned long last_updated; /* in jiffies */
  
  	/* register values */
  	int temp[TEMP_IDX_LEN];
  
  	u16 fan[FAN1_IDX_LEN];
  	u8 fan1_div;
  
  	u8 pwm1;
  	u8 temp1_auto_point_temp[3];
  	u8 temp2_auto_point_temp[3];
  	u8 pwm1_auto_point_pwm[3];
  	u8 pwm1_enable;
  	u8 pwm1_auto_channels_temp;
  
  	u8 stat1;
  	u8 stat2;
  };
  
  
  static ssize_t get_temp(
  		struct device *dev,
  		struct device_attribute *devattr,
  		char *buf)
  {
  	struct amc6821_data *data = amc6821_update_device(dev);
  	int ix = to_sensor_dev_attr(devattr)->index;
  
  	return sprintf(buf, "%d
  ", data->temp[ix] * 1000);
  }
  
  
  
  static ssize_t set_temp(
  		struct device *dev,
  		struct device_attribute *attr,
  		const char *buf,
  		size_t count)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct amc6821_data *data = i2c_get_clientdata(client);
  	int ix = to_sensor_dev_attr(attr)->index;
  	long val;
  
  	int ret = kstrtol(buf, 10, &val);
  	if (ret)
  		return ret;
  	val = clamp_val(val / 1000, -128, 127);
  
  	mutex_lock(&data->update_lock);
  	data->temp[ix] = val;
  	if (i2c_smbus_write_byte_data(client, temp_reg[ix], data->temp[ix])) {
  		dev_err(&client->dev, "Register write error, aborting.
  ");
  		count = -EIO;
  	}
  	mutex_unlock(&data->update_lock);
  	return count;
  }
  
  
  
  
  static ssize_t get_temp_alarm(
  	struct device *dev,
  	struct device_attribute *devattr,
  	char *buf)
  {
  	struct amc6821_data *data = amc6821_update_device(dev);
  	int ix = to_sensor_dev_attr(devattr)->index;
  	u8 flag;
  
  	switch (ix) {
  	case IDX_TEMP1_MIN:
  		flag = data->stat1 & AMC6821_STAT1_LTL;
  		break;
  	case IDX_TEMP1_MAX:
  		flag = data->stat1 & AMC6821_STAT1_LTH;
  		break;
  	case IDX_TEMP1_CRIT:
  		flag = data->stat2 & AMC6821_STAT2_LTC;
  		break;
  	case IDX_TEMP2_MIN:
  		flag = data->stat1 & AMC6821_STAT1_RTL;
  		break;
  	case IDX_TEMP2_MAX:
  		flag = data->stat1 & AMC6821_STAT1_RTH;
  		break;
  	case IDX_TEMP2_CRIT:
  		flag = data->stat2 & AMC6821_STAT2_RTC;
  		break;
  	default:
  		dev_dbg(dev, "Unknown attr->index (%d).
  ", ix);
  		return -EINVAL;
  	}
  	if (flag)
  		return sprintf(buf, "1");
  	else
  		return sprintf(buf, "0");
  }
  
  
  
  
  static ssize_t get_temp2_fault(
  		struct device *dev,
  		struct device_attribute *devattr,
  		char *buf)
  {
  	struct amc6821_data *data = amc6821_update_device(dev);
  	if (data->stat1 & AMC6821_STAT1_RTF)
  		return sprintf(buf, "1");
  	else
  		return sprintf(buf, "0");
  }
  
  static ssize_t get_pwm1(
  		struct device *dev,
  		struct device_attribute *devattr,
  		char *buf)
  {
  	struct amc6821_data *data = amc6821_update_device(dev);
  	return sprintf(buf, "%d
  ", data->pwm1);
  }
  
  static ssize_t set_pwm1(
  		struct device *dev,
  		struct device_attribute *devattr,
  		const char *buf,
  		size_t count)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct amc6821_data *data = i2c_get_clientdata(client);
  	long val;
  	int ret = kstrtol(buf, 10, &val);
  	if (ret)
  		return ret;
  
  	mutex_lock(&data->update_lock);
  	data->pwm1 = clamp_val(val , 0, 255);
  	i2c_smbus_write_byte_data(client, AMC6821_REG_DCY, data->pwm1);
  	mutex_unlock(&data->update_lock);
  	return count;
  }
  
  static ssize_t get_pwm1_enable(
  		struct device *dev,
  		struct device_attribute *devattr,
  		char *buf)
  {
  	struct amc6821_data *data = amc6821_update_device(dev);
  	return sprintf(buf, "%d
  ", data->pwm1_enable);
  }
  
  static ssize_t set_pwm1_enable(
  		struct device *dev,
  		struct device_attribute *attr,
  		const char *buf,
  		size_t count)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct amc6821_data *data = i2c_get_clientdata(client);
  	long val;
  	int config = kstrtol(buf, 10, &val);
  	if (config)
  		return config;
  
  	mutex_lock(&data->update_lock);
  	config = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF1);
  	if (config < 0) {
  			dev_err(&client->dev,
  			"Error reading configuration register, aborting.
  ");
  			count = config;
  			goto unlock;
  	}
  
  	switch (val) {
  	case 1:
  		config &= ~AMC6821_CONF1_FDRC0;
  		config &= ~AMC6821_CONF1_FDRC1;
  		break;
  	case 2:
  		config &= ~AMC6821_CONF1_FDRC0;
  		config |= AMC6821_CONF1_FDRC1;
  		break;
  	case 3:
  		config |= AMC6821_CONF1_FDRC0;
  		config |= AMC6821_CONF1_FDRC1;
  		break;
  	default:
  		count = -EINVAL;
  		goto unlock;
  	}
  	if (i2c_smbus_write_byte_data(client, AMC6821_REG_CONF1, config)) {
  			dev_err(&client->dev,
  			"Configuration register write error, aborting.
  ");
  			count = -EIO;
  	}
  unlock:
  	mutex_unlock(&data->update_lock);
  	return count;
  }
  
  
  static ssize_t get_pwm1_auto_channels_temp(
  		struct device *dev,
  		struct device_attribute *devattr,
  		char *buf)
  {
  	struct amc6821_data *data = amc6821_update_device(dev);
  	return sprintf(buf, "%d
  ", data->pwm1_auto_channels_temp);
  }
  
  
  static ssize_t get_temp_auto_point_temp(
  		struct device *dev,
  		struct device_attribute *devattr,
  		char *buf)
  {
  	int ix = to_sensor_dev_attr_2(devattr)->index;
  	int nr = to_sensor_dev_attr_2(devattr)->nr;
  	struct amc6821_data *data = amc6821_update_device(dev);
  	switch (nr) {
  	case 1:
  		return sprintf(buf, "%d
  ",
  			data->temp1_auto_point_temp[ix] * 1000);
  	case 2:
  		return sprintf(buf, "%d
  ",
  			data->temp2_auto_point_temp[ix] * 1000);
  	default:
  		dev_dbg(dev, "Unknown attr->nr (%d).
  ", nr);
  		return -EINVAL;
  	}
  }
  
  
  static ssize_t get_pwm1_auto_point_pwm(
  		struct device *dev,
  		struct device_attribute *devattr,
  		char *buf)
  {
  	int ix = to_sensor_dev_attr(devattr)->index;
  	struct amc6821_data *data = amc6821_update_device(dev);
  	return sprintf(buf, "%d
  ", data->pwm1_auto_point_pwm[ix]);
  }
  
  
  static inline ssize_t set_slope_register(struct i2c_client *client,
  		u8 reg,
  		u8 dpwm,
  		u8 *ptemp)
  {
  	int dt;
  	u8 tmp;
  
  	dt = ptemp[2]-ptemp[1];
  	for (tmp = 4; tmp > 0; tmp--) {
  		if (dt * (0x20 >> tmp) >= dpwm)
  			break;
  	}
  	tmp |= (ptemp[1] & 0x7C) << 1;
  	if (i2c_smbus_write_byte_data(client,
  			reg, tmp)) {
  		dev_err(&client->dev, "Register write error, aborting.
  ");
  		return -EIO;
  	}
  	return 0;
  }
  
  
  
  static ssize_t set_temp_auto_point_temp(
  		struct device *dev,
  		struct device_attribute *attr,
  		const char *buf,
  		size_t count)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct amc6821_data *data = amc6821_update_device(dev);
  	int ix = to_sensor_dev_attr_2(attr)->index;
  	int nr = to_sensor_dev_attr_2(attr)->nr;
  	u8 *ptemp;
  	u8 reg;
  	int dpwm;
  	long val;
  	int ret = kstrtol(buf, 10, &val);
  	if (ret)
  		return ret;
  
  	switch (nr) {
  	case 1:
  		ptemp = data->temp1_auto_point_temp;
  		reg = AMC6821_REG_LTEMP_FAN_CTRL;
  		break;
  	case 2:
  		ptemp = data->temp2_auto_point_temp;
  		reg = AMC6821_REG_RTEMP_FAN_CTRL;
  		break;
  	default:
  		dev_dbg(dev, "Unknown attr->nr (%d).
  ", nr);
  		return -EINVAL;
  	}
  
  	mutex_lock(&data->update_lock);
  	data->valid = 0;
  
  	switch (ix) {
  	case 0:
  		ptemp[0] = clamp_val(val / 1000, 0,
  				     data->temp1_auto_point_temp[1]);
  		ptemp[0] = clamp_val(ptemp[0], 0,
  				     data->temp2_auto_point_temp[1]);
  		ptemp[0] = clamp_val(ptemp[0], 0, 63);
  		if (i2c_smbus_write_byte_data(
  					client,
  					AMC6821_REG_PSV_TEMP,
  					ptemp[0])) {
  				dev_err(&client->dev,
  					"Register write error, aborting.
  ");
  				count = -EIO;
  		}
  		goto EXIT;
  	case 1:
  		ptemp[1] = clamp_val(val / 1000, (ptemp[0] & 0x7C) + 4, 124);
  		ptemp[1] &= 0x7C;
  		ptemp[2] = clamp_val(ptemp[2], ptemp[1] + 1, 255);
  		break;
  	case 2:
  		ptemp[2] = clamp_val(val / 1000, ptemp[1]+1, 255);
  		break;
  	default:
  		dev_dbg(dev, "Unknown attr->index (%d).
  ", ix);
  		count = -EINVAL;
  		goto EXIT;
  	}
  	dpwm = data->pwm1_auto_point_pwm[2] - data->pwm1_auto_point_pwm[1];
  	if (set_slope_register(client, reg, dpwm, ptemp))
  		count = -EIO;
  
  EXIT:
  	mutex_unlock(&data->update_lock);
  	return count;
  }
  
  
  
  static ssize_t set_pwm1_auto_point_pwm(
  		struct device *dev,
  		struct device_attribute *attr,
  		const char *buf,
  		size_t count)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct amc6821_data *data = i2c_get_clientdata(client);
  	int dpwm;
  	long val;
  	int ret = kstrtol(buf, 10, &val);
  	if (ret)
  		return ret;
  
  	mutex_lock(&data->update_lock);
  	data->pwm1_auto_point_pwm[1] = clamp_val(val, 0, 254);
  	if (i2c_smbus_write_byte_data(client, AMC6821_REG_DCY_LOW_TEMP,
  			data->pwm1_auto_point_pwm[1])) {
  		dev_err(&client->dev, "Register write error, aborting.
  ");
  		count = -EIO;
  		goto EXIT;
  	}
  	dpwm = data->pwm1_auto_point_pwm[2] - data->pwm1_auto_point_pwm[1];
  	if (set_slope_register(client, AMC6821_REG_LTEMP_FAN_CTRL, dpwm,
  			data->temp1_auto_point_temp)) {
  		count = -EIO;
  		goto EXIT;
  	}
  	if (set_slope_register(client, AMC6821_REG_RTEMP_FAN_CTRL, dpwm,
  			data->temp2_auto_point_temp)) {
  		count = -EIO;
  		goto EXIT;
  	}
  
  EXIT:
  	data->valid = 0;
  	mutex_unlock(&data->update_lock);
  	return count;
  }
  
  static ssize_t get_fan(
  		struct device *dev,
  		struct device_attribute *devattr,
  		char *buf)
  {
  	struct amc6821_data *data = amc6821_update_device(dev);
  	int ix = to_sensor_dev_attr(devattr)->index;
  	if (0 == data->fan[ix])
  		return sprintf(buf, "0");
  	return sprintf(buf, "%d
  ", (int)(6000000 / data->fan[ix]));
  }
  
  
  
  static ssize_t get_fan1_fault(
  		struct device *dev,
  		struct device_attribute *devattr,
  		char *buf)
  {
  	struct amc6821_data *data = amc6821_update_device(dev);
  	if (data->stat1 & AMC6821_STAT1_FANS)
  		return sprintf(buf, "1");
  	else
  		return sprintf(buf, "0");
  }
  
  
  
  static ssize_t set_fan(
  		struct device *dev,
  		struct device_attribute *attr,
  		const char *buf, size_t count)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct amc6821_data *data = i2c_get_clientdata(client);
  	long val;
  	int ix = to_sensor_dev_attr(attr)->index;
  	int ret = kstrtol(buf, 10, &val);
  	if (ret)
  		return ret;
  	val = 1 > val ? 0xFFFF : 6000000/val;
  
  	mutex_lock(&data->update_lock);
  	data->fan[ix] = (u16) clamp_val(val, 1, 0xFFFF);
  	if (i2c_smbus_write_byte_data(client, fan_reg_low[ix],
  			data->fan[ix] & 0xFF)) {
  		dev_err(&client->dev, "Register write error, aborting.
  ");
  		count = -EIO;
  		goto EXIT;
  	}
  	if (i2c_smbus_write_byte_data(client,
  			fan_reg_hi[ix], data->fan[ix] >> 8)) {
  		dev_err(&client->dev, "Register write error, aborting.
  ");
  		count = -EIO;
  	}
  EXIT:
  	mutex_unlock(&data->update_lock);
  	return count;
  }
  
  
  
  static ssize_t get_fan1_div(
  		struct device *dev,
  		struct device_attribute *devattr,
  		char *buf)
  {
  	struct amc6821_data *data = amc6821_update_device(dev);
  	return sprintf(buf, "%d
  ", data->fan1_div);
  }
  
  static ssize_t set_fan1_div(
  		struct device *dev,
  		struct device_attribute *attr,
  		const char *buf, size_t count)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct amc6821_data *data = i2c_get_clientdata(client);
  	long val;
  	int config = kstrtol(buf, 10, &val);
  	if (config)
  		return config;
  
  	mutex_lock(&data->update_lock);
  	config = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF4);
  	if (config < 0) {
  		dev_err(&client->dev,
  			"Error reading configuration register, aborting.
  ");
  		count = config;
  		goto EXIT;
  	}
  	switch (val) {
  	case 2:
  		config &= ~AMC6821_CONF4_PSPR;
  		data->fan1_div = 2;
  		break;
  	case 4:
  		config |= AMC6821_CONF4_PSPR;
  		data->fan1_div = 4;
  		break;
  	default:
  		count = -EINVAL;
  		goto EXIT;
  	}
  	if (i2c_smbus_write_byte_data(client, AMC6821_REG_CONF4, config)) {
  		dev_err(&client->dev,
  			"Configuration register write error, aborting.
  ");
  		count = -EIO;
  	}
  EXIT:
  	mutex_unlock(&data->update_lock);
  	return count;
  }
  
  
  
  static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
  	get_temp, NULL, IDX_TEMP1_INPUT);
  static SENSOR_DEVICE_ATTR(temp1_min, S_IRUGO | S_IWUSR, get_temp,
  	set_temp, IDX_TEMP1_MIN);
  static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO | S_IWUSR, get_temp,
  	set_temp, IDX_TEMP1_MAX);
  static SENSOR_DEVICE_ATTR(temp1_crit, S_IRUGO | S_IWUSR, get_temp,
  	set_temp, IDX_TEMP1_CRIT);
  static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO,
  	get_temp_alarm, NULL, IDX_TEMP1_MIN);
  static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO,
  	get_temp_alarm, NULL, IDX_TEMP1_MAX);
  static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO,
  	get_temp_alarm, NULL, IDX_TEMP1_CRIT);
  static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO,
  	get_temp, NULL, IDX_TEMP2_INPUT);
  static SENSOR_DEVICE_ATTR(temp2_min, S_IRUGO | S_IWUSR, get_temp,
  	set_temp, IDX_TEMP2_MIN);
  static SENSOR_DEVICE_ATTR(temp2_max, S_IRUGO | S_IWUSR, get_temp,
  	set_temp, IDX_TEMP2_MAX);
  static SENSOR_DEVICE_ATTR(temp2_crit, S_IRUGO | S_IWUSR, get_temp,
  	set_temp, IDX_TEMP2_CRIT);
  static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO,
  	get_temp2_fault, NULL, 0);
  static SENSOR_DEVICE_ATTR(temp2_min_alarm, S_IRUGO,
  	get_temp_alarm, NULL, IDX_TEMP2_MIN);
  static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO,
  	get_temp_alarm, NULL, IDX_TEMP2_MAX);
  static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO,
  	get_temp_alarm, NULL, IDX_TEMP2_CRIT);
  static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, get_fan, NULL, IDX_FAN1_INPUT);
  static SENSOR_DEVICE_ATTR(fan1_min, S_IRUGO | S_IWUSR,
  	get_fan, set_fan, IDX_FAN1_MIN);
  static SENSOR_DEVICE_ATTR(fan1_max, S_IRUGO | S_IWUSR,
  	get_fan, set_fan, IDX_FAN1_MAX);
  static SENSOR_DEVICE_ATTR(fan1_fault, S_IRUGO, get_fan1_fault, NULL, 0);
  static SENSOR_DEVICE_ATTR(fan1_div, S_IRUGO | S_IWUSR,
  	get_fan1_div, set_fan1_div, 0);
  
  static SENSOR_DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, get_pwm1, set_pwm1, 0);
  static SENSOR_DEVICE_ATTR(pwm1_enable, S_IWUSR | S_IRUGO,
  	get_pwm1_enable, set_pwm1_enable, 0);
  static SENSOR_DEVICE_ATTR(pwm1_auto_point1_pwm, S_IRUGO,
  	get_pwm1_auto_point_pwm, NULL, 0);
  static SENSOR_DEVICE_ATTR(pwm1_auto_point2_pwm, S_IWUSR | S_IRUGO,
  	get_pwm1_auto_point_pwm, set_pwm1_auto_point_pwm, 1);
  static SENSOR_DEVICE_ATTR(pwm1_auto_point3_pwm, S_IRUGO,
  	get_pwm1_auto_point_pwm, NULL, 2);
  static SENSOR_DEVICE_ATTR(pwm1_auto_channels_temp, S_IRUGO,
  	get_pwm1_auto_channels_temp, NULL, 0);
  static SENSOR_DEVICE_ATTR_2(temp1_auto_point1_temp, S_IRUGO,
  	get_temp_auto_point_temp, NULL, 1, 0);
  static SENSOR_DEVICE_ATTR_2(temp1_auto_point2_temp, S_IWUSR | S_IRUGO,
  	get_temp_auto_point_temp, set_temp_auto_point_temp, 1, 1);
  static SENSOR_DEVICE_ATTR_2(temp1_auto_point3_temp, S_IWUSR | S_IRUGO,
  	get_temp_auto_point_temp, set_temp_auto_point_temp, 1, 2);
  
  static SENSOR_DEVICE_ATTR_2(temp2_auto_point1_temp, S_IWUSR | S_IRUGO,
  	get_temp_auto_point_temp, set_temp_auto_point_temp, 2, 0);
  static SENSOR_DEVICE_ATTR_2(temp2_auto_point2_temp, S_IWUSR | S_IRUGO,
  	get_temp_auto_point_temp, set_temp_auto_point_temp, 2, 1);
  static SENSOR_DEVICE_ATTR_2(temp2_auto_point3_temp, S_IWUSR | S_IRUGO,
  	get_temp_auto_point_temp, set_temp_auto_point_temp, 2, 2);
  
  
  
  static struct attribute *amc6821_attrs[] = {
  	&sensor_dev_attr_temp1_input.dev_attr.attr,
  	&sensor_dev_attr_temp1_min.dev_attr.attr,
  	&sensor_dev_attr_temp1_max.dev_attr.attr,
  	&sensor_dev_attr_temp1_crit.dev_attr.attr,
  	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp2_input.dev_attr.attr,
  	&sensor_dev_attr_temp2_min.dev_attr.attr,
  	&sensor_dev_attr_temp2_max.dev_attr.attr,
  	&sensor_dev_attr_temp2_crit.dev_attr.attr,
  	&sensor_dev_attr_temp2_min_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp2_fault.dev_attr.attr,
  	&sensor_dev_attr_fan1_input.dev_attr.attr,
  	&sensor_dev_attr_fan1_min.dev_attr.attr,
  	&sensor_dev_attr_fan1_max.dev_attr.attr,
  	&sensor_dev_attr_fan1_fault.dev_attr.attr,
  	&sensor_dev_attr_fan1_div.dev_attr.attr,
  	&sensor_dev_attr_pwm1.dev_attr.attr,
  	&sensor_dev_attr_pwm1_enable.dev_attr.attr,
  	&sensor_dev_attr_pwm1_auto_channels_temp.dev_attr.attr,
  	&sensor_dev_attr_pwm1_auto_point1_pwm.dev_attr.attr,
  	&sensor_dev_attr_pwm1_auto_point2_pwm.dev_attr.attr,
  	&sensor_dev_attr_pwm1_auto_point3_pwm.dev_attr.attr,
  	&sensor_dev_attr_temp1_auto_point1_temp.dev_attr.attr,
  	&sensor_dev_attr_temp1_auto_point2_temp.dev_attr.attr,
  	&sensor_dev_attr_temp1_auto_point3_temp.dev_attr.attr,
  	&sensor_dev_attr_temp2_auto_point1_temp.dev_attr.attr,
  	&sensor_dev_attr_temp2_auto_point2_temp.dev_attr.attr,
  	&sensor_dev_attr_temp2_auto_point3_temp.dev_attr.attr,
  	NULL
  };
  
  static struct attribute_group amc6821_attr_grp = {
  	.attrs = amc6821_attrs,
  };
  
  
  
  /* Return 0 if detection is successful, -ENODEV otherwise */
  static int amc6821_detect(
  		struct i2c_client *client,
  		struct i2c_board_info *info)
  {
  	struct i2c_adapter *adapter = client->adapter;
  	int address = client->addr;
  	int dev_id, comp_id;
  
  	dev_dbg(&adapter->dev, "amc6821_detect called.
  ");
  
  	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
  		dev_dbg(&adapter->dev,
  			"amc6821: I2C bus doesn't support byte mode, "
  			"skipping.
  ");
  		return -ENODEV;
  	}
  
  	dev_id = i2c_smbus_read_byte_data(client, AMC6821_REG_DEV_ID);
  	comp_id = i2c_smbus_read_byte_data(client, AMC6821_REG_COMP_ID);
  	if (dev_id != 0x21 || comp_id != 0x49) {
  		dev_dbg(&adapter->dev,
  			"amc6821: detection failed at 0x%02x.
  ",
  			address);
  		return -ENODEV;
  	}
  
  	/*
  	 * Bit 7 of the address register is ignored, so we can check the
  	 * ID registers again
  	 */
  	dev_id = i2c_smbus_read_byte_data(client, 0x80 | AMC6821_REG_DEV_ID);
  	comp_id = i2c_smbus_read_byte_data(client, 0x80 | AMC6821_REG_COMP_ID);
  	if (dev_id != 0x21 || comp_id != 0x49) {
  		dev_dbg(&adapter->dev,
  			"amc6821: detection failed at 0x%02x.
  ",
  			address);
  		return -ENODEV;
  	}
  
  	dev_info(&adapter->dev, "amc6821: chip found at 0x%02x.
  ", address);
  	strlcpy(info->type, "amc6821", I2C_NAME_SIZE);
  
  	return 0;
  }
  
  static int amc6821_probe(
  	struct i2c_client *client,
  	const struct i2c_device_id *id)
  {
  	struct amc6821_data *data;
  	int err;
  
  	data = devm_kzalloc(&client->dev, sizeof(struct amc6821_data),
  			    GFP_KERNEL);
  	if (!data)
  		return -ENOMEM;
  
  	i2c_set_clientdata(client, data);
  	mutex_init(&data->update_lock);
  
  	/*
  	 * Initialize the amc6821 chip
  	 */
  	err = amc6821_init_client(client);
  	if (err)
  		return err;
  
  	err = sysfs_create_group(&client->dev.kobj, &amc6821_attr_grp);
  	if (err)
  		return err;
  
  	data->hwmon_dev = hwmon_device_register(&client->dev);
  	if (!IS_ERR(data->hwmon_dev))
  		return 0;
  
  	err = PTR_ERR(data->hwmon_dev);
  	dev_err(&client->dev, "error registering hwmon device.
  ");
  	sysfs_remove_group(&client->dev.kobj, &amc6821_attr_grp);
  	return err;
  }
  
  static int amc6821_remove(struct i2c_client *client)
  {
  	struct amc6821_data *data = i2c_get_clientdata(client);
  
  	hwmon_device_unregister(data->hwmon_dev);
  	sysfs_remove_group(&client->dev.kobj, &amc6821_attr_grp);
  
  	return 0;
  }
  
  
  static int amc6821_init_client(struct i2c_client *client)
  {
  	int config;
  	int err = -EIO;
  
  	if (init) {
  		config = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF4);
  
  		if (config < 0) {
  				dev_err(&client->dev,
  			"Error reading configuration register, aborting.
  ");
  				return err;
  		}
  
  		config |= AMC6821_CONF4_MODE;
  
  		if (i2c_smbus_write_byte_data(client, AMC6821_REG_CONF4,
  				config)) {
  			dev_err(&client->dev,
  			"Configuration register write error, aborting.
  ");
  			return err;
  		}
  
  		config = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF3);
  
  		if (config < 0) {
  			dev_err(&client->dev,
  			"Error reading configuration register, aborting.
  ");
  			return err;
  		}
  
  		dev_info(&client->dev, "Revision %d
  ", config & 0x0f);
  
  		config &= ~AMC6821_CONF3_THERM_FAN_EN;
  
  		if (i2c_smbus_write_byte_data(client, AMC6821_REG_CONF3,
  				config)) {
  			dev_err(&client->dev,
  			"Configuration register write error, aborting.
  ");
  			return err;
  		}
  
  		config = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF2);
  
  		if (config < 0) {
  			dev_err(&client->dev,
  			"Error reading configuration register, aborting.
  ");
  			return err;
  		}
  
  		config &= ~AMC6821_CONF2_RTFIE;
  		config &= ~AMC6821_CONF2_LTOIE;
  		config &= ~AMC6821_CONF2_RTOIE;
  		if (i2c_smbus_write_byte_data(client,
  				AMC6821_REG_CONF2, config)) {
  			dev_err(&client->dev,
  			"Configuration register write error, aborting.
  ");
  			return err;
  		}
  
  		config = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF1);
  
  		if (config < 0) {
  			dev_err(&client->dev,
  			"Error reading configuration register, aborting.
  ");
  			return err;
  		}
  
  		config &= ~AMC6821_CONF1_THERMOVIE;
  		config &= ~AMC6821_CONF1_FANIE;
  		config |= AMC6821_CONF1_START;
  		if (pwminv)
  			config |= AMC6821_CONF1_PWMINV;
  		else
  			config &= ~AMC6821_CONF1_PWMINV;
  
  		if (i2c_smbus_write_byte_data(
  				client, AMC6821_REG_CONF1, config)) {
  			dev_err(&client->dev,
  			"Configuration register write error, aborting.
  ");
  			return err;
  		}
  	}
  	return 0;
  }
  
  
  static struct amc6821_data *amc6821_update_device(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct amc6821_data *data = i2c_get_clientdata(client);
  	int timeout = HZ;
  	u8 reg;
  	int i;
  
  	mutex_lock(&data->update_lock);
  
  	if (time_after(jiffies, data->last_updated + timeout) ||
  			!data->valid) {
  
  		for (i = 0; i < TEMP_IDX_LEN; i++)
  			data->temp[i] = i2c_smbus_read_byte_data(client,
  				temp_reg[i]);
  
  		data->stat1 = i2c_smbus_read_byte_data(client,
  			AMC6821_REG_STAT1);
  		data->stat2 = i2c_smbus_read_byte_data(client,
  			AMC6821_REG_STAT2);
  
  		data->pwm1 = i2c_smbus_read_byte_data(client,
  			AMC6821_REG_DCY);
  		for (i = 0; i < FAN1_IDX_LEN; i++) {
  			data->fan[i] = i2c_smbus_read_byte_data(
  					client,
  					fan_reg_low[i]);
  			data->fan[i] += i2c_smbus_read_byte_data(
  					client,
  					fan_reg_hi[i]) << 8;
  		}
  		data->fan1_div = i2c_smbus_read_byte_data(client,
  			AMC6821_REG_CONF4);
  		data->fan1_div = data->fan1_div & AMC6821_CONF4_PSPR ? 4 : 2;
  
  		data->pwm1_auto_point_pwm[0] = 0;
  		data->pwm1_auto_point_pwm[2] = 255;
  		data->pwm1_auto_point_pwm[1] = i2c_smbus_read_byte_data(client,
  			AMC6821_REG_DCY_LOW_TEMP);
  
  		data->temp1_auto_point_temp[0] =
  			i2c_smbus_read_byte_data(client,
  					AMC6821_REG_PSV_TEMP);
  		data->temp2_auto_point_temp[0] =
  				data->temp1_auto_point_temp[0];
  		reg = i2c_smbus_read_byte_data(client,
  			AMC6821_REG_LTEMP_FAN_CTRL);
  		data->temp1_auto_point_temp[1] = (reg & 0xF8) >> 1;
  		reg &= 0x07;
  		reg = 0x20 >> reg;
  		if (reg > 0)
  			data->temp1_auto_point_temp[2] =
  				data->temp1_auto_point_temp[1] +
  				(data->pwm1_auto_point_pwm[2] -
  				data->pwm1_auto_point_pwm[1]) / reg;
  		else
  			data->temp1_auto_point_temp[2] = 255;
  
  		reg = i2c_smbus_read_byte_data(client,
  			AMC6821_REG_RTEMP_FAN_CTRL);
  		data->temp2_auto_point_temp[1] = (reg & 0xF8) >> 1;
  		reg &= 0x07;
  		reg = 0x20 >> reg;
  		if (reg > 0)
  			data->temp2_auto_point_temp[2] =
  				data->temp2_auto_point_temp[1] +
  				(data->pwm1_auto_point_pwm[2] -
  				data->pwm1_auto_point_pwm[1]) / reg;
  		else
  			data->temp2_auto_point_temp[2] = 255;
  
  		reg = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF1);
  		reg = (reg >> 5) & 0x3;
  		switch (reg) {
  		case 0: /*open loop: software sets pwm1*/
  			data->pwm1_auto_channels_temp = 0;
  			data->pwm1_enable = 1;
  			break;
  		case 2: /*closed loop: remote T (temp2)*/
  			data->pwm1_auto_channels_temp = 2;
  			data->pwm1_enable = 2;
  			break;
  		case 3: /*closed loop: local and remote T (temp2)*/
  			data->pwm1_auto_channels_temp = 3;
  			data->pwm1_enable = 3;
  			break;
  		case 1: /*
  			 * semi-open loop: software sets rpm, chip controls
  			 * pwm1, currently not implemented
  			 */
  			data->pwm1_auto_channels_temp = 0;
  			data->pwm1_enable = 0;
  			break;
  		}
  
  		data->last_updated = jiffies;
  		data->valid = 1;
  	}
  	mutex_unlock(&data->update_lock);
  	return data;
  }
  
  module_i2c_driver(amc6821_driver);
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("T. Mertelj <tomaz.mertelj@guest.arnes.si>");
  MODULE_DESCRIPTION("Texas Instruments amc6821 hwmon driver");