/*
   * gl518sm.c - Part of lm_sensors, Linux kernel modules for hardware
   *             monitoring
   * Copyright (C) 1998, 1999 Frodo Looijaard <frodol@dds.nl> and
   * Kyosti Malkki <kmalkki@cc.hut.fi>
   * Copyright (C) 2004 Hong-Gunn Chew <hglinux@gunnet.org> and
   * Jean Delvare <khali@linux-fr.org>
   *
   * 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.
   *
   * Ported to Linux 2.6 by Hong-Gunn Chew with the help of Jean Delvare
   * and advice of Greg Kroah-Hartman.
   *
   * Notes about the port:
   * Release 0x00 of the GL518SM chipset doesn't support reading of in0,
   * in1 nor in2. The original driver had an ugly workaround to get them
   * anyway (changing limits and watching alarms trigger and wear off).
   * We did not keep that part of the original driver in the Linux 2.6
   * version, since it was making the driver significantly more complex
   * with no real benefit.

   */

  #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>

  #include <linux/sysfs.h>

  
  /* Addresses to scan */

  static const unsigned short normal_i2c[] = { 0x2c, 0x2d, I2C_CLIENT_END };

  enum chips { gl518sm_r00, gl518sm_r80 };

  
  /* Many GL518 constants specified below */
  
  /* The GL518 registers */
  #define GL518_REG_CHIP_ID	0x00
  #define GL518_REG_REVISION	0x01
  #define GL518_REG_VENDOR_ID	0x02
  #define GL518_REG_CONF		0x03
  #define GL518_REG_TEMP_IN	0x04
  #define GL518_REG_TEMP_MAX	0x05
  #define GL518_REG_TEMP_HYST	0x06
  #define GL518_REG_FAN_COUNT	0x07
  #define GL518_REG_FAN_LIMIT	0x08
  #define GL518_REG_VIN1_LIMIT	0x09
  #define GL518_REG_VIN2_LIMIT	0x0a
  #define GL518_REG_VIN3_LIMIT	0x0b
  #define GL518_REG_VDD_LIMIT	0x0c
  #define GL518_REG_VIN3		0x0d
  #define GL518_REG_MISC		0x0f
  #define GL518_REG_ALARM		0x10
  #define GL518_REG_MASK		0x11
  #define GL518_REG_INT		0x12
  #define GL518_REG_VIN2		0x13
  #define GL518_REG_VIN1		0x14
  #define GL518_REG_VDD		0x15
  
  
  /*
   * Conversions. Rounding and limit checking is only done on the TO_REG
   * variants. Note that you should be a bit careful with which arguments
   * these macros are called: arguments may be evaluated more than once.
   * Fixing this is just not worth it.
   */
  
  #define RAW_FROM_REG(val)	val
  
  #define BOOL_FROM_REG(val)	((val)?0:1)
  #define BOOL_TO_REG(val)	((val)?0:1)
  
  #define TEMP_TO_REG(val)	(SENSORS_LIMIT(((((val)<0? \
  				(val)-500:(val)+500)/1000)+119),0,255))
  #define TEMP_FROM_REG(val)	(((val) - 119) * 1000)
  
  static inline u8 FAN_TO_REG(long rpm, int div)
  {
  	long rpmdiv;
  	if (rpm == 0)
  		return 0;

  	rpmdiv = SENSORS_LIMIT(rpm, 1, 960000) * div;
  	return SENSORS_LIMIT((480000 + rpmdiv / 2) / rpmdiv, 1, 255);

  }

  #define FAN_FROM_REG(val,div)	((val)==0 ? 0 : (480000/((val)*(div))))

  
  #define IN_TO_REG(val)		(SENSORS_LIMIT((((val)+9)/19),0,255))
  #define IN_FROM_REG(val)	((val)*19)
  
  #define VDD_TO_REG(val)		(SENSORS_LIMIT((((val)*4+47)/95),0,255))
  #define VDD_FROM_REG(val)	(((val)*95+2)/4)

  #define DIV_FROM_REG(val)	(1 << (val))
  
  #define BEEP_MASK_TO_REG(val)	((val) & 0x7f & data->alarm_mask)
  #define BEEP_MASK_FROM_REG(val)	((val) & 0x7f)
  
  /* Each client has this additional data */
  struct gl518_data {

  	struct device *hwmon_dev;

  	enum chips type;

  	struct mutex update_lock;

  	char valid;		/* !=0 if following fields are valid */
  	unsigned long last_updated;	/* In jiffies */
  
  	u8 voltage_in[4];	/* Register values; [0] = VDD */
  	u8 voltage_min[4];	/* Register values; [0] = VDD */
  	u8 voltage_max[4];	/* Register values; [0] = VDD */

  	u8 fan_in[2];
  	u8 fan_min[2];
  	u8 fan_div[2];		/* Register encoding, shifted right */
  	u8 fan_auto1;		/* Boolean */
  	u8 temp_in;		/* Register values */
  	u8 temp_max;		/* Register values */
  	u8 temp_hyst;		/* Register values */
  	u8 alarms;		/* Register value */

  	u8 alarm_mask;

  	u8 beep_mask;		/* Register value */
  	u8 beep_enable;		/* Boolean */
  };

  static int gl518_probe(struct i2c_client *client,
  		       const struct i2c_device_id *id);

  static int gl518_detect(struct i2c_client *client, struct i2c_board_info *info);

  static void gl518_init_client(struct i2c_client *client);

  static int gl518_remove(struct i2c_client *client);

  static int gl518_read_value(struct i2c_client *client, u8 reg);
  static int gl518_write_value(struct i2c_client *client, u8 reg, u16 value);
  static struct gl518_data *gl518_update_device(struct device *dev);

  static const struct i2c_device_id gl518_id[] = {
  	{ "gl518sm", 0 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, gl518_id);

  /* This is the driver that will be inserted */
  static struct i2c_driver gl518_driver = {

  	.class		= I2C_CLASS_HWMON,

  	.driver = {

  		.name	= "gl518sm",
  	},

  	.probe		= gl518_probe,
  	.remove		= gl518_remove,
  	.id_table	= gl518_id,
  	.detect		= gl518_detect,

  	.address_list	= normal_i2c,

  };
  
  /*
   * Sysfs stuff
   */
  
  #define show(type, suffix, value)					\

  static ssize_t show_##suffix(struct device *dev, struct device_attribute *attr, char *buf)		\

  {									\
  	struct gl518_data *data = gl518_update_device(dev);		\
  	return sprintf(buf, "%d
  ", type##_FROM_REG(data->value));	\
  }

  show(TEMP, temp_input1, temp_in);
  show(TEMP, temp_max1, temp_max);
  show(TEMP, temp_hyst1, temp_hyst);
  show(BOOL, fan_auto1, fan_auto1);

  show(VDD, in_input0, voltage_in[0]);
  show(IN, in_input1, voltage_in[1]);
  show(IN, in_input2, voltage_in[2]);
  show(IN, in_input3, voltage_in[3]);
  show(VDD, in_min0, voltage_min[0]);
  show(IN, in_min1, voltage_min[1]);
  show(IN, in_min2, voltage_min[2]);
  show(IN, in_min3, voltage_min[3]);
  show(VDD, in_max0, voltage_max[0]);
  show(IN, in_max1, voltage_max[1]);
  show(IN, in_max2, voltage_max[2]);
  show(IN, in_max3, voltage_max[3]);
  show(RAW, alarms, alarms);
  show(BOOL, beep_enable, beep_enable);
  show(BEEP_MASK, beep_mask, beep_mask);

  static ssize_t show_fan_input(struct device *dev,
  			      struct device_attribute *attr, char *buf)
  {
  	int nr = to_sensor_dev_attr(attr)->index;
  	struct gl518_data *data = gl518_update_device(dev);
  	return sprintf(buf, "%d
  ", FAN_FROM_REG(data->fan_in[nr],
  					DIV_FROM_REG(data->fan_div[nr])));
  }
  
  static ssize_t show_fan_min(struct device *dev,
  			    struct device_attribute *attr, char *buf)
  {
  	int nr = to_sensor_dev_attr(attr)->index;
  	struct gl518_data *data = gl518_update_device(dev);
  	return sprintf(buf, "%d
  ", FAN_FROM_REG(data->fan_min[nr],
  					DIV_FROM_REG(data->fan_div[nr])));
  }
  
  static ssize_t show_fan_div(struct device *dev,
  			    struct device_attribute *attr, char *buf)
  {
  	int nr = to_sensor_dev_attr(attr)->index;
  	struct gl518_data *data = gl518_update_device(dev);
  	return sprintf(buf, "%d
  ", DIV_FROM_REG(data->fan_div[nr]));
  }

  #define set(type, suffix, value, reg)					\

  static ssize_t set_##suffix(struct device *dev, struct device_attribute *attr, const char *buf,	\

  	size_t count)							\
  {									\
  	struct i2c_client *client = to_i2c_client(dev);			\
  	struct gl518_data *data = i2c_get_clientdata(client);		\
  	long val = simple_strtol(buf, NULL, 10);			\
  									\

  	mutex_lock(&data->update_lock);					\

  	data->value = type##_TO_REG(val);				\
  	gl518_write_value(client, reg, data->value);			\

  	mutex_unlock(&data->update_lock);				\

  	return count;							\
  }
  
  #define set_bits(type, suffix, value, reg, mask, shift)			\

  static ssize_t set_##suffix(struct device *dev, struct device_attribute *attr, const char *buf,	\

  	size_t count)							\
  {									\
  	struct i2c_client *client = to_i2c_client(dev);			\
  	struct gl518_data *data = i2c_get_clientdata(client);		\
  	int regvalue;							\
  	unsigned long val = simple_strtoul(buf, NULL, 10);		\
  									\

  	mutex_lock(&data->update_lock);					\

  	regvalue = gl518_read_value(client, reg);			\
  	data->value = type##_TO_REG(val);				\
  	regvalue = (regvalue & ~mask) | (data->value << shift);		\
  	gl518_write_value(client, reg, regvalue);			\

  	mutex_unlock(&data->update_lock);				\

  	return count;							\
  }
  
  #define set_low(type, suffix, value, reg)				\
  	set_bits(type, suffix, value, reg, 0x00ff, 0)
  #define set_high(type, suffix, value, reg)				\
  	set_bits(type, suffix, value, reg, 0xff00, 8)
  
  set(TEMP, temp_max1, temp_max, GL518_REG_TEMP_MAX);
  set(TEMP, temp_hyst1, temp_hyst, GL518_REG_TEMP_HYST);
  set_bits(BOOL, fan_auto1, fan_auto1, GL518_REG_MISC, 0x08, 3);

  set_low(VDD, in_min0, voltage_min[0], GL518_REG_VDD_LIMIT);
  set_low(IN, in_min1, voltage_min[1], GL518_REG_VIN1_LIMIT);
  set_low(IN, in_min2, voltage_min[2], GL518_REG_VIN2_LIMIT);
  set_low(IN, in_min3, voltage_min[3], GL518_REG_VIN3_LIMIT);
  set_high(VDD, in_max0, voltage_max[0], GL518_REG_VDD_LIMIT);
  set_high(IN, in_max1, voltage_max[1], GL518_REG_VIN1_LIMIT);
  set_high(IN, in_max2, voltage_max[2], GL518_REG_VIN2_LIMIT);
  set_high(IN, in_max3, voltage_max[3], GL518_REG_VIN3_LIMIT);
  set_bits(BOOL, beep_enable, beep_enable, GL518_REG_CONF, 0x04, 2);
  set(BEEP_MASK, beep_mask, beep_mask, GL518_REG_ALARM);

  static ssize_t set_fan_min(struct device *dev, struct device_attribute *attr,
  			   const char *buf, size_t count)

  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct gl518_data *data = i2c_get_clientdata(client);

  	int nr = to_sensor_dev_attr(attr)->index;

  	int regvalue;
  	unsigned long val = simple_strtoul(buf, NULL, 10);

  	mutex_lock(&data->update_lock);

  	regvalue = gl518_read_value(client, GL518_REG_FAN_LIMIT);

  	data->fan_min[nr] = FAN_TO_REG(val, DIV_FROM_REG(data->fan_div[nr]));
  	regvalue = (regvalue & (0xff << (8 * nr)))
  		 | (data->fan_min[nr] << (8 * (1 - nr)));

  	gl518_write_value(client, GL518_REG_FAN_LIMIT, regvalue);
  
  	data->beep_mask = gl518_read_value(client, GL518_REG_ALARM);

  	if (data->fan_min[nr] == 0)
  		data->alarm_mask &= ~(0x20 << nr);

  	else

  		data->alarm_mask |= (0x20 << nr);

  	data->beep_mask &= data->alarm_mask;
  	gl518_write_value(client, GL518_REG_ALARM, data->beep_mask);

  	mutex_unlock(&data->update_lock);

  	return count;
  }

  static ssize_t set_fan_div(struct device *dev, struct device_attribute *attr,
  			   const char *buf, size_t count)

  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct gl518_data *data = i2c_get_clientdata(client);

  	int nr = to_sensor_dev_attr(attr)->index;

  	int regvalue;
  	unsigned long val = simple_strtoul(buf, NULL, 10);

  	switch (val) {
  	case 1: val = 0; break;
  	case 2: val = 1; break;
  	case 4: val = 2; break;
  	case 8: val = 3; break;
  	default:
  		dev_err(dev, "Invalid fan clock divider %lu, choose one "
  			"of 1, 2, 4 or 8
  ", val);
  		return -EINVAL;
  	}

  	mutex_lock(&data->update_lock);

  	regvalue = gl518_read_value(client, GL518_REG_MISC);

  	data->fan_div[nr] = val;

  	regvalue = (regvalue & ~(0xc0 >> (2 * nr)))
  		 | (data->fan_div[nr] << (6 - 2 * nr));
  	gl518_write_value(client, GL518_REG_MISC, regvalue);

  	mutex_unlock(&data->update_lock);

  	return count;
  }
  
  static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input1, NULL);
  static DEVICE_ATTR(temp1_max, S_IWUSR|S_IRUGO, show_temp_max1, set_temp_max1);
  static DEVICE_ATTR(temp1_max_hyst, S_IWUSR|S_IRUGO,
  	show_temp_hyst1, set_temp_hyst1);
  static DEVICE_ATTR(fan1_auto, S_IWUSR|S_IRUGO, show_fan_auto1, set_fan_auto1);

  static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, show_fan_input, NULL, 0);
  static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, show_fan_input, NULL, 1);
  static SENSOR_DEVICE_ATTR(fan1_min, S_IWUSR|S_IRUGO,
  	show_fan_min, set_fan_min, 0);
  static SENSOR_DEVICE_ATTR(fan2_min, S_IWUSR|S_IRUGO,
  	show_fan_min, set_fan_min, 1);
  static SENSOR_DEVICE_ATTR(fan1_div, S_IWUSR|S_IRUGO,
  	show_fan_div, set_fan_div, 0);
  static SENSOR_DEVICE_ATTR(fan2_div, S_IWUSR|S_IRUGO,
  	show_fan_div, set_fan_div, 1);

  static DEVICE_ATTR(in0_input, S_IRUGO, show_in_input0, NULL);
  static DEVICE_ATTR(in1_input, S_IRUGO, show_in_input1, NULL);
  static DEVICE_ATTR(in2_input, S_IRUGO, show_in_input2, NULL);
  static DEVICE_ATTR(in3_input, S_IRUGO, show_in_input3, NULL);
  static DEVICE_ATTR(in0_min, S_IWUSR|S_IRUGO, show_in_min0, set_in_min0);
  static DEVICE_ATTR(in1_min, S_IWUSR|S_IRUGO, show_in_min1, set_in_min1);
  static DEVICE_ATTR(in2_min, S_IWUSR|S_IRUGO, show_in_min2, set_in_min2);
  static DEVICE_ATTR(in3_min, S_IWUSR|S_IRUGO, show_in_min3, set_in_min3);
  static DEVICE_ATTR(in0_max, S_IWUSR|S_IRUGO, show_in_max0, set_in_max0);
  static DEVICE_ATTR(in1_max, S_IWUSR|S_IRUGO, show_in_max1, set_in_max1);
  static DEVICE_ATTR(in2_max, S_IWUSR|S_IRUGO, show_in_max2, set_in_max2);
  static DEVICE_ATTR(in3_max, S_IWUSR|S_IRUGO, show_in_max3, set_in_max3);
  static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
  static DEVICE_ATTR(beep_enable, S_IWUSR|S_IRUGO,
  	show_beep_enable, set_beep_enable);
  static DEVICE_ATTR(beep_mask, S_IWUSR|S_IRUGO,
  	show_beep_mask, set_beep_mask);

  static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
  			  char *buf)
  {
  	int bitnr = to_sensor_dev_attr(attr)->index;
  	struct gl518_data *data = gl518_update_device(dev);
  	return sprintf(buf, "%u
  ", (data->alarms >> bitnr) & 1);
  }
  
  static SENSOR_DEVICE_ATTR(in0_alarm, S_IRUGO, show_alarm, NULL, 0);
  static SENSOR_DEVICE_ATTR(in1_alarm, S_IRUGO, show_alarm, NULL, 1);
  static SENSOR_DEVICE_ATTR(in2_alarm, S_IRUGO, show_alarm, NULL, 2);
  static SENSOR_DEVICE_ATTR(in3_alarm, S_IRUGO, show_alarm, NULL, 3);
  static SENSOR_DEVICE_ATTR(temp1_alarm, S_IRUGO, show_alarm, NULL, 4);
  static SENSOR_DEVICE_ATTR(fan1_alarm, S_IRUGO, show_alarm, NULL, 5);
  static SENSOR_DEVICE_ATTR(fan2_alarm, S_IRUGO, show_alarm, NULL, 6);
  
  static ssize_t show_beep(struct device *dev, struct device_attribute *attr,
  			  char *buf)
  {
  	int bitnr = to_sensor_dev_attr(attr)->index;
  	struct gl518_data *data = gl518_update_device(dev);
  	return sprintf(buf, "%u
  ", (data->beep_mask >> bitnr) & 1);
  }
  
  static ssize_t set_beep(struct device *dev, struct device_attribute *attr,
  			const char *buf, size_t count)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct gl518_data *data = i2c_get_clientdata(client);
  	int bitnr = to_sensor_dev_attr(attr)->index;
  	unsigned long bit;
  
  	bit = simple_strtoul(buf, NULL, 10);
  	if (bit & ~1)
  		return -EINVAL;
  
  	mutex_lock(&data->update_lock);
  	data->beep_mask = gl518_read_value(client, GL518_REG_ALARM);
  	if (bit)
  		data->beep_mask |= (1 << bitnr);
  	else
  		data->beep_mask &= ~(1 << bitnr);
  	gl518_write_value(client, GL518_REG_ALARM, data->beep_mask);
  	mutex_unlock(&data->update_lock);
  	return count;
  }
  
  static SENSOR_DEVICE_ATTR(in0_beep, S_IRUGO|S_IWUSR, show_beep, set_beep, 0);
  static SENSOR_DEVICE_ATTR(in1_beep, S_IRUGO|S_IWUSR, show_beep, set_beep, 1);
  static SENSOR_DEVICE_ATTR(in2_beep, S_IRUGO|S_IWUSR, show_beep, set_beep, 2);
  static SENSOR_DEVICE_ATTR(in3_beep, S_IRUGO|S_IWUSR, show_beep, set_beep, 3);
  static SENSOR_DEVICE_ATTR(temp1_beep, S_IRUGO|S_IWUSR, show_beep, set_beep, 4);
  static SENSOR_DEVICE_ATTR(fan1_beep, S_IRUGO|S_IWUSR, show_beep, set_beep, 5);
  static SENSOR_DEVICE_ATTR(fan2_beep, S_IRUGO|S_IWUSR, show_beep, set_beep, 6);

  static struct attribute *gl518_attributes[] = {

  	&dev_attr_in3_input.attr,
  	&dev_attr_in0_min.attr,
  	&dev_attr_in1_min.attr,
  	&dev_attr_in2_min.attr,
  	&dev_attr_in3_min.attr,
  	&dev_attr_in0_max.attr,
  	&dev_attr_in1_max.attr,
  	&dev_attr_in2_max.attr,
  	&dev_attr_in3_max.attr,

  	&sensor_dev_attr_in0_alarm.dev_attr.attr,
  	&sensor_dev_attr_in1_alarm.dev_attr.attr,
  	&sensor_dev_attr_in2_alarm.dev_attr.attr,
  	&sensor_dev_attr_in3_alarm.dev_attr.attr,
  	&sensor_dev_attr_in0_beep.dev_attr.attr,
  	&sensor_dev_attr_in1_beep.dev_attr.attr,
  	&sensor_dev_attr_in2_beep.dev_attr.attr,
  	&sensor_dev_attr_in3_beep.dev_attr.attr,

  
  	&dev_attr_fan1_auto.attr,

  	&sensor_dev_attr_fan1_input.dev_attr.attr,
  	&sensor_dev_attr_fan2_input.dev_attr.attr,
  	&sensor_dev_attr_fan1_min.dev_attr.attr,
  	&sensor_dev_attr_fan2_min.dev_attr.attr,
  	&sensor_dev_attr_fan1_div.dev_attr.attr,
  	&sensor_dev_attr_fan2_div.dev_attr.attr,

  	&sensor_dev_attr_fan1_alarm.dev_attr.attr,
  	&sensor_dev_attr_fan2_alarm.dev_attr.attr,
  	&sensor_dev_attr_fan1_beep.dev_attr.attr,
  	&sensor_dev_attr_fan2_beep.dev_attr.attr,

  
  	&dev_attr_temp1_input.attr,
  	&dev_attr_temp1_max.attr,
  	&dev_attr_temp1_max_hyst.attr,

  	&sensor_dev_attr_temp1_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp1_beep.dev_attr.attr,

  
  	&dev_attr_alarms.attr,
  	&dev_attr_beep_enable.attr,
  	&dev_attr_beep_mask.attr,
  	NULL
  };
  
  static const struct attribute_group gl518_group = {
  	.attrs = gl518_attributes,
  };

  static struct attribute *gl518_attributes_r80[] = {
  	&dev_attr_in0_input.attr,
  	&dev_attr_in1_input.attr,
  	&dev_attr_in2_input.attr,
  	NULL
  };
  
  static const struct attribute_group gl518_group_r80 = {
  	.attrs = gl518_attributes_r80,
  };

  /*
   * Real code
   */

  /* Return 0 if detection is successful, -ENODEV otherwise */

  static int gl518_detect(struct i2c_client *client, struct i2c_board_info *info)

  {

  	struct i2c_adapter *adapter = client->adapter;

  	int rev;

  
  	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
  				     I2C_FUNC_SMBUS_WORD_DATA))

  		return -ENODEV;

  
  	/* Now, we do the remaining detection. */

  	if ((gl518_read_value(client, GL518_REG_CHIP_ID) != 0x80)
  	 || (gl518_read_value(client, GL518_REG_CONF) & 0x80))
  		return -ENODEV;

  
  	/* Determine the chip type. */

  	rev = gl518_read_value(client, GL518_REG_REVISION);
  	if (rev != 0x00 && rev != 0x80)
  		return -ENODEV;

  	strlcpy(info->type, "gl518sm", I2C_NAME_SIZE);

  	return 0;
  }
  
  static int gl518_probe(struct i2c_client *client,
  		       const struct i2c_device_id *id)
  {
  	struct gl518_data *data;
  	int err, revision;
  
  	data = kzalloc(sizeof(struct gl518_data), GFP_KERNEL);
  	if (!data) {
  		err = -ENOMEM;
  		goto exit;
  	}
  
  	i2c_set_clientdata(client, data);
  	revision = gl518_read_value(client, GL518_REG_REVISION);
  	data->type = revision == 0x80 ? gl518sm_r80 : gl518sm_r00;
  	mutex_init(&data->update_lock);

  
  	/* Initialize the GL518SM chip */
  	data->alarm_mask = 0xff;

  	gl518_init_client(client);

  
  	/* Register sysfs hooks */

  	if ((err = sysfs_create_group(&client->dev.kobj, &gl518_group)))

  		goto exit_free;

  	if (data->type == gl518sm_r80)
  		if ((err = sysfs_create_group(&client->dev.kobj,
  					      &gl518_group_r80)))
  			goto exit_remove_files;

  	data->hwmon_dev = hwmon_device_register(&client->dev);

  	if (IS_ERR(data->hwmon_dev)) {
  		err = PTR_ERR(data->hwmon_dev);

  		goto exit_remove_files;

  	}

  	return 0;

  exit_remove_files:

  	sysfs_remove_group(&client->dev.kobj, &gl518_group);

  	if (data->type == gl518sm_r80)
  		sysfs_remove_group(&client->dev.kobj, &gl518_group_r80);

  exit_free:
  	kfree(data);
  exit:
  	return err;
  }
  
  
  /* Called when we have found a new GL518SM.
     Note that we preserve D4:NoFan2 and D2:beep_enable. */
  static void gl518_init_client(struct i2c_client *client)
  {
  	/* Make sure we leave D7:Reset untouched */
  	u8 regvalue = gl518_read_value(client, GL518_REG_CONF) & 0x7f;
  
  	/* Comparator mode (D3=0), standby mode (D6=0) */
  	gl518_write_value(client, GL518_REG_CONF, (regvalue &= 0x37));
  
  	/* Never interrupts */
  	gl518_write_value(client, GL518_REG_MASK, 0x00);
  
  	/* Clear status register (D5=1), start (D6=1) */
  	gl518_write_value(client, GL518_REG_CONF, 0x20 | regvalue);
  	gl518_write_value(client, GL518_REG_CONF, 0x40 | regvalue);
  }

  static int gl518_remove(struct i2c_client *client)

  {

  	struct gl518_data *data = i2c_get_clientdata(client);

  	hwmon_device_unregister(data->hwmon_dev);

  	sysfs_remove_group(&client->dev.kobj, &gl518_group);

  	if (data->type == gl518sm_r80)
  		sysfs_remove_group(&client->dev.kobj, &gl518_group_r80);

  	kfree(data);

  	return 0;
  }

  /* Registers 0x07 to 0x0c are word-sized, others are byte-sized

     GL518 uses a high-byte first convention, which is exactly opposite to

     the SMBus standard. */

  static int gl518_read_value(struct i2c_client *client, u8 reg)
  {
  	if ((reg >= 0x07) && (reg <= 0x0c))

  		return i2c_smbus_read_word_swapped(client, reg);

  	else
  		return i2c_smbus_read_byte_data(client, reg);
  }

  static int gl518_write_value(struct i2c_client *client, u8 reg, u16 value)
  {
  	if ((reg >= 0x07) && (reg <= 0x0c))

  		return i2c_smbus_write_word_swapped(client, reg, value);

  	else
  		return i2c_smbus_write_byte_data(client, reg, value);
  }
  
  static struct gl518_data *gl518_update_device(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct gl518_data *data = i2c_get_clientdata(client);
  	int val;

  	mutex_lock(&data->update_lock);

  
  	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
  	    || !data->valid) {
  		dev_dbg(&client->dev, "Starting gl518 update
  ");
  
  		data->alarms = gl518_read_value(client, GL518_REG_INT);
  		data->beep_mask = gl518_read_value(client, GL518_REG_ALARM);
  
  		val = gl518_read_value(client, GL518_REG_VDD_LIMIT);
  		data->voltage_min[0] = val & 0xff;
  		data->voltage_max[0] = (val >> 8) & 0xff;
  		val = gl518_read_value(client, GL518_REG_VIN1_LIMIT);
  		data->voltage_min[1] = val & 0xff;
  		data->voltage_max[1] = (val >> 8) & 0xff;
  		val = gl518_read_value(client, GL518_REG_VIN2_LIMIT);
  		data->voltage_min[2] = val & 0xff;
  		data->voltage_max[2] = (val >> 8) & 0xff;
  		val = gl518_read_value(client, GL518_REG_VIN3_LIMIT);
  		data->voltage_min[3] = val & 0xff;
  		data->voltage_max[3] = (val >> 8) & 0xff;
  
  		val = gl518_read_value(client, GL518_REG_FAN_COUNT);
  		data->fan_in[0] = (val >> 8) & 0xff;
  		data->fan_in[1] = val & 0xff;
  
  		val = gl518_read_value(client, GL518_REG_FAN_LIMIT);
  		data->fan_min[0] = (val >> 8) & 0xff;
  		data->fan_min[1] = val & 0xff;
  
  		data->temp_in = gl518_read_value(client, GL518_REG_TEMP_IN);
  		data->temp_max =
  		    gl518_read_value(client, GL518_REG_TEMP_MAX);
  		data->temp_hyst =
  		    gl518_read_value(client, GL518_REG_TEMP_HYST);
  
  		val = gl518_read_value(client, GL518_REG_MISC);
  		data->fan_div[0] = (val >> 6) & 0x03;
  		data->fan_div[1] = (val >> 4) & 0x03;
  		data->fan_auto1  = (val >> 3) & 0x01;
  
  		data->alarms &= data->alarm_mask;
  
  		val = gl518_read_value(client, GL518_REG_CONF);
  		data->beep_enable = (val >> 2) & 1;
  
  		if (data->type != gl518sm_r00) {
  			data->voltage_in[0] =
  			    gl518_read_value(client, GL518_REG_VDD);
  			data->voltage_in[1] =
  			    gl518_read_value(client, GL518_REG_VIN1);
  			data->voltage_in[2] =
  			    gl518_read_value(client, GL518_REG_VIN2);
  		}
  		data->voltage_in[3] =
  		    gl518_read_value(client, GL518_REG_VIN3);
  
  		data->last_updated = jiffies;
  		data->valid = 1;
  	}

  	mutex_unlock(&data->update_lock);

  
  	return data;
  }
  
  static int __init sensors_gl518sm_init(void)
  {
  	return i2c_add_driver(&gl518_driver);
  }
  
  static void __exit sensors_gl518sm_exit(void)
  {
  	i2c_del_driver(&gl518_driver);
  }
  
  MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>, "
  	"Kyosti Malkki <kmalkki@cc.hut.fi> and "
  	"Hong-Gunn Chew <hglinux@gunnet.org>");
  MODULE_DESCRIPTION("GL518SM driver");
  MODULE_LICENSE("GPL");
  
  module_init(sensors_gl518sm_init);
  module_exit(sensors_gl518sm_exit);