/*

   * lm78.c - Part of lm_sensors, Linux kernel modules for hardware
   *	    monitoring
   * Copyright (c) 1998, 1999  Frodo Looijaard <frodol@dds.nl>

   * Copyright (c) 2007, 2011  Jean Delvare <jdelvare@suse.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.
   */

  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

  #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-vid.h>

  #include <linux/hwmon-sysfs.h>

  #include <linux/err.h>

  #include <linux/mutex.h>

  #ifdef CONFIG_ISA
  #include <linux/platform_device.h>
  #include <linux/ioport.h>
  #include <linux/io.h>
  #endif

  /* Addresses to scan */

  static const unsigned short normal_i2c[] = { 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d,
  						0x2e, 0x2f, I2C_CLIENT_END };

  enum chips { lm78, lm79 };

  
  /* Many LM78 constants specified below */
  
  /* Length of ISA address segment */
  #define LM78_EXTENT 8
  
  /* Where are the ISA address/data registers relative to the base address */
  #define LM78_ADDR_REG_OFFSET 5
  #define LM78_DATA_REG_OFFSET 6
  
  /* The LM78 registers */
  #define LM78_REG_IN_MAX(nr) (0x2b + (nr) * 2)
  #define LM78_REG_IN_MIN(nr) (0x2c + (nr) * 2)
  #define LM78_REG_IN(nr) (0x20 + (nr))
  
  #define LM78_REG_FAN_MIN(nr) (0x3b + (nr))
  #define LM78_REG_FAN(nr) (0x28 + (nr))
  
  #define LM78_REG_TEMP 0x27
  #define LM78_REG_TEMP_OVER 0x39
  #define LM78_REG_TEMP_HYST 0x3a
  
  #define LM78_REG_ALARM1 0x41
  #define LM78_REG_ALARM2 0x42
  
  #define LM78_REG_VID_FANDIV 0x47
  
  #define LM78_REG_CONFIG 0x40
  #define LM78_REG_CHIPID 0x49
  #define LM78_REG_I2C_ADDR 0x48

  /*
   * Conversions. Rounding and limit checking is only done on the TO_REG
   * variants.
   */

  /*
   * IN: mV (0V to 4.08V)
   * REG: 16mV/bit
   */

  static inline u8 IN_TO_REG(unsigned long val)
  {

  	unsigned long nval = clamp_val(val, 0, 4080);

  	return (nval + 8) / 16;
  }
  #define IN_FROM_REG(val) ((val) *  16)
  
  static inline u8 FAN_TO_REG(long rpm, int div)
  {
  	if (rpm <= 0)
  		return 255;

  	if (rpm > 1350000)
  		return 1;

  	return clamp_val((1350000 + rpm * div / 2) / (rpm * div), 1, 254);

  }
  
  static inline int FAN_FROM_REG(u8 val, int div)
  {

  	return val == 0 ? -1 : val == 255 ? 0 : 1350000 / (val * div);

  }

  /*
   * TEMP: mC (-128C to +127C)
   * REG: 1C/bit, two's complement
   */

  static inline s8 TEMP_TO_REG(long val)

  {

  	int nval = clamp_val(val, -128000, 127000) ;

  	return nval < 0 ? (nval - 500) / 1000 : (nval + 500) / 1000;

  }
  
  static inline int TEMP_FROM_REG(s8 val)
  {
  	return val * 1000;
  }

  #define DIV_FROM_REG(val) (1 << (val))

  struct lm78_data {

  	struct i2c_client *client;

  	struct mutex lock;

  	enum chips type;

  	/* For ISA device only */
  	const char *name;
  	int isa_addr;

  	struct mutex update_lock;

  	char valid;		/* !=0 if following fields are valid */
  	unsigned long last_updated;	/* In jiffies */
  
  	u8 in[7];		/* Register value */
  	u8 in_max[7];		/* Register value */
  	u8 in_min[7];		/* Register value */
  	u8 fan[3];		/* Register value */
  	u8 fan_min[3];		/* Register value */
  	s8 temp;		/* Register value */
  	s8 temp_over;		/* Register value */
  	s8 temp_hyst;		/* Register value */
  	u8 fan_div[3];		/* Register encoding, shifted right */
  	u8 vid;			/* Register encoding, combined */
  	u16 alarms;		/* Register encoding, combined */
  };

  static int lm78_read_value(struct lm78_data *data, u8 reg);
  static int lm78_write_value(struct lm78_data *data, u8 reg, u8 value);

  static struct lm78_data *lm78_update_device(struct device *dev);

  static void lm78_init_device(struct lm78_data *data);

  /* 7 Voltages */

  static ssize_t show_in(struct device *dev, struct device_attribute *da,
  		       char *buf)

  {

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);

  	struct lm78_data *data = lm78_update_device(dev);

  	return sprintf(buf, "%d
  ", IN_FROM_REG(data->in[attr->index]));

  }

  static ssize_t show_in_min(struct device *dev, struct device_attribute *da,
  			   char *buf)

  {

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);

  	struct lm78_data *data = lm78_update_device(dev);

  	return sprintf(buf, "%d
  ", IN_FROM_REG(data->in_min[attr->index]));

  }

  static ssize_t show_in_max(struct device *dev, struct device_attribute *da,
  			   char *buf)

  {

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);

  	struct lm78_data *data = lm78_update_device(dev);

  	return sprintf(buf, "%d
  ", IN_FROM_REG(data->in_max[attr->index]));

  }

  static ssize_t set_in_min(struct device *dev, struct device_attribute *da,
  			  const char *buf, size_t count)

  {

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);

  	struct lm78_data *data = dev_get_drvdata(dev);

  	int nr = attr->index;

  	unsigned long val;
  	int err;
  
  	err = kstrtoul(buf, 10, &val);
  	if (err)
  		return err;

  	mutex_lock(&data->update_lock);

  	data->in_min[nr] = IN_TO_REG(val);

  	lm78_write_value(data, LM78_REG_IN_MIN(nr), data->in_min[nr]);

  	mutex_unlock(&data->update_lock);

  	return count;
  }

  static ssize_t set_in_max(struct device *dev, struct device_attribute *da,
  			  const char *buf, size_t count)

  {

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);

  	struct lm78_data *data = dev_get_drvdata(dev);

  	int nr = attr->index;

  	unsigned long val;
  	int err;
  
  	err = kstrtoul(buf, 10, &val);
  	if (err)
  		return err;

  	mutex_lock(&data->update_lock);

  	data->in_max[nr] = IN_TO_REG(val);

  	lm78_write_value(data, LM78_REG_IN_MAX(nr), data->in_max[nr]);

  	mutex_unlock(&data->update_lock);

  	return count;
  }

  #define show_in_offset(offset)					\

  static SENSOR_DEVICE_ATTR(in##offset##_input, S_IRUGO,		\
  		show_in, NULL, offset);				\
  static SENSOR_DEVICE_ATTR(in##offset##_min, S_IRUGO | S_IWUSR,	\
  		show_in_min, set_in_min, offset);		\
  static SENSOR_DEVICE_ATTR(in##offset##_max, S_IRUGO | S_IWUSR,	\
  		show_in_max, set_in_max, offset);

  
  show_in_offset(0);
  show_in_offset(1);
  show_in_offset(2);
  show_in_offset(3);
  show_in_offset(4);
  show_in_offset(5);
  show_in_offset(6);
  
  /* Temperature */

  static ssize_t show_temp(struct device *dev, struct device_attribute *da,
  			 char *buf)

  {
  	struct lm78_data *data = lm78_update_device(dev);
  	return sprintf(buf, "%d
  ", TEMP_FROM_REG(data->temp));
  }

  static ssize_t show_temp_over(struct device *dev, struct device_attribute *da,
  			      char *buf)

  {
  	struct lm78_data *data = lm78_update_device(dev);
  	return sprintf(buf, "%d
  ", TEMP_FROM_REG(data->temp_over));
  }

  static ssize_t set_temp_over(struct device *dev, struct device_attribute *da,
  			     const char *buf, size_t count)

  {

  	struct lm78_data *data = dev_get_drvdata(dev);

  	long val;
  	int err;
  
  	err = kstrtol(buf, 10, &val);
  	if (err)
  		return err;

  	mutex_lock(&data->update_lock);

  	data->temp_over = TEMP_TO_REG(val);

  	lm78_write_value(data, LM78_REG_TEMP_OVER, data->temp_over);

  	mutex_unlock(&data->update_lock);

  	return count;
  }

  static ssize_t show_temp_hyst(struct device *dev, struct device_attribute *da,
  			      char *buf)

  {
  	struct lm78_data *data = lm78_update_device(dev);
  	return sprintf(buf, "%d
  ", TEMP_FROM_REG(data->temp_hyst));
  }

  static ssize_t set_temp_hyst(struct device *dev, struct device_attribute *da,
  			     const char *buf, size_t count)

  {

  	struct lm78_data *data = dev_get_drvdata(dev);

  	long val;
  	int err;
  
  	err = kstrtol(buf, 10, &val);
  	if (err)
  		return err;

  	mutex_lock(&data->update_lock);

  	data->temp_hyst = TEMP_TO_REG(val);

  	lm78_write_value(data, LM78_REG_TEMP_HYST, data->temp_hyst);

  	mutex_unlock(&data->update_lock);

  	return count;
  }
  
  static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL);
  static DEVICE_ATTR(temp1_max, S_IRUGO | S_IWUSR,
  		show_temp_over, set_temp_over);
  static DEVICE_ATTR(temp1_max_hyst, S_IRUGO | S_IWUSR,
  		show_temp_hyst, set_temp_hyst);
  
  /* 3 Fans */

  static ssize_t show_fan(struct device *dev, struct device_attribute *da,
  			char *buf)

  {

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);

  	struct lm78_data *data = lm78_update_device(dev);

  	int nr = attr->index;

  	return sprintf(buf, "%d
  ", FAN_FROM_REG(data->fan[nr],

  		DIV_FROM_REG(data->fan_div[nr])));

  }

  static ssize_t show_fan_min(struct device *dev, struct device_attribute *da,
  			    char *buf)

  {

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);

  	struct lm78_data *data = lm78_update_device(dev);

  	int nr = attr->index;

  	return sprintf(buf, "%d
  ", FAN_FROM_REG(data->fan_min[nr],
  		DIV_FROM_REG(data->fan_div[nr])));

  }

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

  {

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);

  	struct lm78_data *data = dev_get_drvdata(dev);

  	int nr = attr->index;

  	unsigned long val;
  	int err;
  
  	err = kstrtoul(buf, 10, &val);
  	if (err)
  		return err;

  	mutex_lock(&data->update_lock);

  	data->fan_min[nr] = FAN_TO_REG(val, DIV_FROM_REG(data->fan_div[nr]));

  	lm78_write_value(data, LM78_REG_FAN_MIN(nr), data->fan_min[nr]);

  	mutex_unlock(&data->update_lock);

  	return count;
  }

  static ssize_t show_fan_div(struct device *dev, struct device_attribute *da,
  			    char *buf)

  {

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);

  	struct lm78_data *data = lm78_update_device(dev);

  	return sprintf(buf, "%d
  ", DIV_FROM_REG(data->fan_div[attr->index]));

  }

  /*
   * Note: we save and restore the fan minimum here, because its value is
   * determined in part by the fan divisor.  This follows the principle of
   * least surprise; the user doesn't expect the fan minimum to change just
   * because the divisor changed.
   */

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

  {

  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);

  	struct lm78_data *data = dev_get_drvdata(dev);

  	int nr = attr->index;

  	unsigned long min;
  	u8 reg;

  	unsigned long val;
  	int err;
  
  	err = kstrtoul(buf, 10, &val);
  	if (err)
  		return err;

  	mutex_lock(&data->update_lock);

  	min = FAN_FROM_REG(data->fan_min[nr],
  			   DIV_FROM_REG(data->fan_div[nr]));
  
  	switch (val) {

  	case 1:
  		data->fan_div[nr] = 0;
  		break;
  	case 2:
  		data->fan_div[nr] = 1;
  		break;
  	case 4:
  		data->fan_div[nr] = 2;
  		break;
  	case 8:
  		data->fan_div[nr] = 3;
  		break;

  	default:

  		dev_err(dev,
  			"fan_div value %ld not supported. Choose one of 1, 2, 4 or 8!
  ",
  			val);

  		mutex_unlock(&data->update_lock);

  		return -EINVAL;
  	}

  	reg = lm78_read_value(data, LM78_REG_VID_FANDIV);

  	switch (nr) {
  	case 0:
  		reg = (reg & 0xcf) | (data->fan_div[nr] << 4);
  		break;
  	case 1:
  		reg = (reg & 0x3f) | (data->fan_div[nr] << 6);
  		break;
  	}

  	lm78_write_value(data, LM78_REG_VID_FANDIV, reg);

  
  	data->fan_min[nr] =
  		FAN_TO_REG(min, DIV_FROM_REG(data->fan_div[nr]));

  	lm78_write_value(data, LM78_REG_FAN_MIN(nr), data->fan_min[nr]);

  	mutex_unlock(&data->update_lock);

  
  	return count;
  }

  #define show_fan_offset(offset)				\
  static SENSOR_DEVICE_ATTR(fan##offset##_input, S_IRUGO,		\
  		show_fan, NULL, offset - 1);			\
  static SENSOR_DEVICE_ATTR(fan##offset##_min, S_IRUGO | S_IWUSR,	\
  		show_fan_min, set_fan_min, offset - 1);

  
  show_fan_offset(1);
  show_fan_offset(2);
  show_fan_offset(3);
  
  /* Fan 3 divisor is locked in H/W */

  static SENSOR_DEVICE_ATTR(fan1_div, S_IRUGO | S_IWUSR,
  		show_fan_div, set_fan_div, 0);
  static SENSOR_DEVICE_ATTR(fan2_div, S_IRUGO | S_IWUSR,
  		show_fan_div, set_fan_div, 1);
  static SENSOR_DEVICE_ATTR(fan3_div, S_IRUGO, show_fan_div, NULL, 2);

  
  /* VID */

  static ssize_t show_vid(struct device *dev, struct device_attribute *da,
  			char *buf)

  {
  	struct lm78_data *data = lm78_update_device(dev);

  	return sprintf(buf, "%d
  ", vid_from_reg(data->vid, 82));

  }
  static DEVICE_ATTR(cpu0_vid, S_IRUGO, show_vid, NULL);
  
  /* Alarms */

  static ssize_t show_alarms(struct device *dev, struct device_attribute *da,
  			   char *buf)

  {
  	struct lm78_data *data = lm78_update_device(dev);
  	return sprintf(buf, "%u
  ", data->alarms);
  }
  static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);

  static ssize_t show_alarm(struct device *dev, struct device_attribute *da,
  			  char *buf)
  {
  	struct lm78_data *data = lm78_update_device(dev);
  	int nr = to_sensor_dev_attr(da)->index;
  	return sprintf(buf, "%u
  ", (data->alarms >> nr) & 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(in4_alarm, S_IRUGO, show_alarm, NULL, 8);
  static SENSOR_DEVICE_ATTR(in5_alarm, S_IRUGO, show_alarm, NULL, 9);
  static SENSOR_DEVICE_ATTR(in6_alarm, S_IRUGO, show_alarm, NULL, 10);
  static SENSOR_DEVICE_ATTR(fan1_alarm, S_IRUGO, show_alarm, NULL, 6);
  static SENSOR_DEVICE_ATTR(fan2_alarm, S_IRUGO, show_alarm, NULL, 7);
  static SENSOR_DEVICE_ATTR(fan3_alarm, S_IRUGO, show_alarm, NULL, 11);
  static SENSOR_DEVICE_ATTR(temp1_alarm, S_IRUGO, show_alarm, NULL, 4);

  static struct attribute *lm78_attrs[] = {

  	&sensor_dev_attr_in0_input.dev_attr.attr,
  	&sensor_dev_attr_in0_min.dev_attr.attr,
  	&sensor_dev_attr_in0_max.dev_attr.attr,

  	&sensor_dev_attr_in0_alarm.dev_attr.attr,

  	&sensor_dev_attr_in1_input.dev_attr.attr,
  	&sensor_dev_attr_in1_min.dev_attr.attr,
  	&sensor_dev_attr_in1_max.dev_attr.attr,

  	&sensor_dev_attr_in1_alarm.dev_attr.attr,

  	&sensor_dev_attr_in2_input.dev_attr.attr,
  	&sensor_dev_attr_in2_min.dev_attr.attr,
  	&sensor_dev_attr_in2_max.dev_attr.attr,

  	&sensor_dev_attr_in2_alarm.dev_attr.attr,

  	&sensor_dev_attr_in3_input.dev_attr.attr,
  	&sensor_dev_attr_in3_min.dev_attr.attr,
  	&sensor_dev_attr_in3_max.dev_attr.attr,

  	&sensor_dev_attr_in3_alarm.dev_attr.attr,

  	&sensor_dev_attr_in4_input.dev_attr.attr,
  	&sensor_dev_attr_in4_min.dev_attr.attr,
  	&sensor_dev_attr_in4_max.dev_attr.attr,

  	&sensor_dev_attr_in4_alarm.dev_attr.attr,

  	&sensor_dev_attr_in5_input.dev_attr.attr,
  	&sensor_dev_attr_in5_min.dev_attr.attr,
  	&sensor_dev_attr_in5_max.dev_attr.attr,

  	&sensor_dev_attr_in5_alarm.dev_attr.attr,

  	&sensor_dev_attr_in6_input.dev_attr.attr,
  	&sensor_dev_attr_in6_min.dev_attr.attr,
  	&sensor_dev_attr_in6_max.dev_attr.attr,

  	&sensor_dev_attr_in6_alarm.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_fan1_input.dev_attr.attr,
  	&sensor_dev_attr_fan1_min.dev_attr.attr,
  	&sensor_dev_attr_fan1_div.dev_attr.attr,

  	&sensor_dev_attr_fan1_alarm.dev_attr.attr,

  	&sensor_dev_attr_fan2_input.dev_attr.attr,
  	&sensor_dev_attr_fan2_min.dev_attr.attr,
  	&sensor_dev_attr_fan2_div.dev_attr.attr,

  	&sensor_dev_attr_fan2_alarm.dev_attr.attr,

  	&sensor_dev_attr_fan3_input.dev_attr.attr,
  	&sensor_dev_attr_fan3_min.dev_attr.attr,
  	&sensor_dev_attr_fan3_div.dev_attr.attr,

  	&sensor_dev_attr_fan3_alarm.dev_attr.attr,

  	&dev_attr_alarms.attr,
  	&dev_attr_cpu0_vid.attr,
  
  	NULL
  };

  ATTRIBUTE_GROUPS(lm78);

  /*
   * ISA related code
   */
  #ifdef CONFIG_ISA
  
  /* ISA device, if found */
  static struct platform_device *pdev;
  
  static unsigned short isa_address = 0x290;

  static struct lm78_data *lm78_data_if_isa(void)
  {
  	return pdev ? platform_get_drvdata(pdev) : NULL;
  }

  /* Returns 1 if the I2C chip appears to be an alias of the ISA chip */
  static int lm78_alias_detect(struct i2c_client *client, u8 chipid)
  {

  	struct lm78_data *isa;

  	int i;
  
  	if (!pdev)	/* No ISA chip */
  		return 0;

  	isa = platform_get_drvdata(pdev);
  
  	if (lm78_read_value(isa, LM78_REG_I2C_ADDR) != client->addr)
  		return 0;	/* Address doesn't match */
  	if ((lm78_read_value(isa, LM78_REG_CHIPID) & 0xfe) != (chipid & 0xfe))
  		return 0;	/* Chip type doesn't match */

  	/*
  	 * We compare all the limit registers, the config register and the
  	 * interrupt mask registers
  	 */

  	for (i = 0x2b; i <= 0x3d; i++) {

  		if (lm78_read_value(isa, i) !=
  		    i2c_smbus_read_byte_data(client, i))

  			return 0;
  	}
  	if (lm78_read_value(isa, LM78_REG_CONFIG) !=

  	    i2c_smbus_read_byte_data(client, LM78_REG_CONFIG))

  		return 0;
  	for (i = 0x43; i <= 0x46; i++) {

  		if (lm78_read_value(isa, i) !=
  		    i2c_smbus_read_byte_data(client, i))

  			return 0;
  	}
  
  	return 1;
  }

  #else /* !CONFIG_ISA */
  
  static int lm78_alias_detect(struct i2c_client *client, u8 chipid)
  {
  	return 0;
  }
  
  static struct lm78_data *lm78_data_if_isa(void)
  {
  	return NULL;
  }
  #endif /* CONFIG_ISA */

  static int lm78_i2c_detect(struct i2c_client *client,

  			   struct i2c_board_info *info)

  {

  	int i;

  	struct lm78_data *isa = lm78_data_if_isa();

  	const char *client_name;
  	struct i2c_adapter *adapter = client->adapter;
  	int address = client->addr;

  	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
  		return -ENODEV;

  	/*
  	 * We block updates of the ISA device to minimize the risk of
  	 * concurrent access to the same LM78 chip through different
  	 * interfaces.
  	 */

  	if (isa)
  		mutex_lock(&isa->update_lock);

  	if ((i2c_smbus_read_byte_data(client, LM78_REG_CONFIG) & 0x80)
  	 || i2c_smbus_read_byte_data(client, LM78_REG_I2C_ADDR) != address)
  		goto err_nodev;
  
  	/* Explicitly prevent the misdetection of Winbond chips */
  	i = i2c_smbus_read_byte_data(client, 0x4f);
  	if (i == 0xa3 || i == 0x5c)
  		goto err_nodev;

  
  	/* Determine the chip type. */

  	i = i2c_smbus_read_byte_data(client, LM78_REG_CHIPID);
  	if (i == 0x00 || i == 0x20	/* LM78 */
  	 || i == 0x40)			/* LM78-J */
  		client_name = "lm78";
  	else if ((i & 0xfe) == 0xc0)
  		client_name = "lm79";
  	else
  		goto err_nodev;
  
  	if (lm78_alias_detect(client, i)) {

  		dev_dbg(&adapter->dev,
  			"Device at 0x%02x appears to be the same as ISA device
  ",
  			address);

  		goto err_nodev;

  	}

  	if (isa)
  		mutex_unlock(&isa->update_lock);

  	strlcpy(info->type, client_name, I2C_NAME_SIZE);

  	return 0;

   err_nodev:
  	if (isa)
  		mutex_unlock(&isa->update_lock);
  	return -ENODEV;
  }
  
  static int lm78_i2c_probe(struct i2c_client *client,
  			  const struct i2c_device_id *id)
  {

  	struct device *dev = &client->dev;
  	struct device *hwmon_dev;

  	struct lm78_data *data;

  	data = devm_kzalloc(dev, sizeof(struct lm78_data), GFP_KERNEL);

  	if (!data)
  		return -ENOMEM;

  	data->client = client;
  	data->type = id->driver_data;

  
  	/* Initialize the LM78 chip */

  	lm78_init_device(data);

  	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
  							   data, lm78_groups);
  	return PTR_ERR_OR_ZERO(hwmon_dev);

  }

  static const struct i2c_device_id lm78_i2c_id[] = {
  	{ "lm78", lm78 },
  	{ "lm79", lm79 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, lm78_i2c_id);

  static struct i2c_driver lm78_driver = {
  	.class		= I2C_CLASS_HWMON,
  	.driver = {
  		.name	= "lm78",
  	},
  	.probe		= lm78_i2c_probe,

  	.id_table	= lm78_i2c_id,
  	.detect		= lm78_i2c_detect,
  	.address_list	= normal_i2c,
  };

  /*
   * The SMBus locks itself, but ISA access must be locked explicitly!
   * We don't want to lock the whole ISA bus, so we lock each client
   * separately.
   * We ignore the LM78 BUSY flag at this moment - it could lead to deadlocks,
   * would slow down the LM78 access and should not be necessary.
   */

  static int lm78_read_value(struct lm78_data *data, u8 reg)

  {

  	struct i2c_client *client = data->client;

  #ifdef CONFIG_ISA

  	if (!client) { /* ISA device */

  		int res;

  		mutex_lock(&data->lock);

  		outb_p(reg, data->isa_addr + LM78_ADDR_REG_OFFSET);
  		res = inb_p(data->isa_addr + LM78_DATA_REG_OFFSET);

  		mutex_unlock(&data->lock);

  		return res;
  	} else

  #endif

  		return i2c_smbus_read_byte_data(client, reg);
  }

  static int lm78_write_value(struct lm78_data *data, u8 reg, u8 value)

  {

  	struct i2c_client *client = data->client;

  #ifdef CONFIG_ISA

  	if (!client) { /* ISA device */

  		mutex_lock(&data->lock);

  		outb_p(reg, data->isa_addr + LM78_ADDR_REG_OFFSET);
  		outb_p(value, data->isa_addr + LM78_DATA_REG_OFFSET);

  		mutex_unlock(&data->lock);

  		return 0;
  	} else

  #endif

  		return i2c_smbus_write_byte_data(client, reg, value);
  }

  static void lm78_init_device(struct lm78_data *data)

  {

  	u8 config;
  	int i;

  
  	/* Start monitoring */

  	config = lm78_read_value(data, LM78_REG_CONFIG);

  	if ((config & 0x09) != 0x01)

  		lm78_write_value(data, LM78_REG_CONFIG,

  				 (config & 0xf7) | 0x01);

  
  	/* A few vars need to be filled upon startup */
  	for (i = 0; i < 3; i++) {

  		data->fan_min[i] = lm78_read_value(data,

  					LM78_REG_FAN_MIN(i));
  	}
  
  	mutex_init(&data->update_lock);

  }
  
  static struct lm78_data *lm78_update_device(struct device *dev)
  {

  	struct lm78_data *data = dev_get_drvdata(dev);

  	int i;

  	mutex_lock(&data->update_lock);

  
  	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
  	    || !data->valid) {

  		dev_dbg(dev, "Starting lm78 update
  ");

  
  		for (i = 0; i <= 6; i++) {
  			data->in[i] =

  			    lm78_read_value(data, LM78_REG_IN(i));

  			data->in_min[i] =

  			    lm78_read_value(data, LM78_REG_IN_MIN(i));

  			data->in_max[i] =

  			    lm78_read_value(data, LM78_REG_IN_MAX(i));

  		}
  		for (i = 0; i < 3; i++) {
  			data->fan[i] =

  			    lm78_read_value(data, LM78_REG_FAN(i));

  			data->fan_min[i] =

  			    lm78_read_value(data, LM78_REG_FAN_MIN(i));

  		}

  		data->temp = lm78_read_value(data, LM78_REG_TEMP);

  		data->temp_over =

  		    lm78_read_value(data, LM78_REG_TEMP_OVER);

  		data->temp_hyst =

  		    lm78_read_value(data, LM78_REG_TEMP_HYST);
  		i = lm78_read_value(data, LM78_REG_VID_FANDIV);

  		data->vid = i & 0x0f;
  		if (data->type == lm79)
  			data->vid |=

  			    (lm78_read_value(data, LM78_REG_CHIPID) &

  			     0x01) << 4;
  		else
  			data->vid |= 0x10;
  		data->fan_div[0] = (i >> 4) & 0x03;
  		data->fan_div[1] = i >> 6;

  		data->alarms = lm78_read_value(data, LM78_REG_ALARM1) +
  		    (lm78_read_value(data, LM78_REG_ALARM2) << 8);

  		data->last_updated = jiffies;
  		data->valid = 1;
  
  		data->fan_div[2] = 1;
  	}

  	mutex_unlock(&data->update_lock);

  
  	return data;
  }

  #ifdef CONFIG_ISA

  static int lm78_isa_probe(struct platform_device *pdev)

  {

  	struct device *dev = &pdev->dev;
  	struct device *hwmon_dev;

  	struct lm78_data *data;
  	struct resource *res;
  
  	/* Reserve the ISA region */
  	res = platform_get_resource(pdev, IORESOURCE_IO, 0);

  	if (!devm_request_region(dev, res->start + LM78_ADDR_REG_OFFSET,

  				 2, "lm78"))
  		return -EBUSY;

  	data = devm_kzalloc(dev, sizeof(struct lm78_data), GFP_KERNEL);

  	if (!data)
  		return -ENOMEM;

  	mutex_init(&data->lock);
  	data->isa_addr = res->start;
  	platform_set_drvdata(pdev, data);
  
  	if (lm78_read_value(data, LM78_REG_CHIPID) & 0x80) {
  		data->type = lm79;
  		data->name = "lm79";
  	} else {
  		data->type = lm78;
  		data->name = "lm78";
  	}
  
  	/* Initialize the LM78 chip */
  	lm78_init_device(data);

  	hwmon_dev = devm_hwmon_device_register_with_groups(dev, data->name,
  							   data, lm78_groups);
  	return PTR_ERR_OR_ZERO(hwmon_dev);

  }
  
  static struct platform_driver lm78_isa_driver = {
  	.driver = {

  		.name	= "lm78",
  	},
  	.probe		= lm78_isa_probe,

  };

  /* return 1 if a supported chip is found, 0 otherwise */
  static int __init lm78_isa_found(unsigned short address)
  {
  	int val, save, found = 0;

  	int port;

  	/*
  	 * Some boards declare base+0 to base+7 as a PNP device, some base+4

  	 * to base+7 and some base+5 to base+6. So we better request each port

  	 * individually for the probing phase.
  	 */

  	for (port = address; port < address + LM78_EXTENT; port++) {
  		if (!request_region(port, 1, "lm78")) {

  			pr_debug("Failed to request port 0x%x
  ", port);

  			goto release;
  		}

  	}

  
  #define REALLY_SLOW_IO

  	/*
  	 * We need the timeouts for at least some LM78-like
  	 * chips. But only if we read 'undefined' registers.
  	 */

  	val = inb_p(address + 1);
  	if (inb_p(address + 2) != val
  	 || inb_p(address + 3) != val
  	 || inb_p(address + 7) != val)
  		goto release;
  #undef REALLY_SLOW_IO

  	/*
  	 * We should be able to change the 7 LSB of the address port. The
  	 * MSB (busy flag) should be clear initially, set after the write.
  	 */

  	save = inb_p(address + LM78_ADDR_REG_OFFSET);
  	if (save & 0x80)
  		goto release;
  	val = ~save & 0x7f;
  	outb_p(val, address + LM78_ADDR_REG_OFFSET);
  	if (inb_p(address + LM78_ADDR_REG_OFFSET) != (val | 0x80)) {
  		outb_p(save, address + LM78_ADDR_REG_OFFSET);
  		goto release;
  	}
  
  	/* We found a device, now see if it could be an LM78 */
  	outb_p(LM78_REG_CONFIG, address + LM78_ADDR_REG_OFFSET);
  	val = inb_p(address + LM78_DATA_REG_OFFSET);
  	if (val & 0x80)
  		goto release;
  	outb_p(LM78_REG_I2C_ADDR, address + LM78_ADDR_REG_OFFSET);
  	val = inb_p(address + LM78_DATA_REG_OFFSET);
  	if (val < 0x03 || val > 0x77)	/* Not a valid I2C address */
  		goto release;
  
  	/* The busy flag should be clear again */
  	if (inb_p(address + LM78_ADDR_REG_OFFSET) & 0x80)
  		goto release;
  
  	/* Explicitly prevent the misdetection of Winbond chips */
  	outb_p(0x4f, address + LM78_ADDR_REG_OFFSET);
  	val = inb_p(address + LM78_DATA_REG_OFFSET);
  	if (val == 0xa3 || val == 0x5c)
  		goto release;
  
  	/* Explicitly prevent the misdetection of ITE chips */
  	outb_p(0x58, address + LM78_ADDR_REG_OFFSET);
  	val = inb_p(address + LM78_DATA_REG_OFFSET);
  	if (val == 0x90)
  		goto release;
  
  	/* Determine the chip type */
  	outb_p(LM78_REG_CHIPID, address + LM78_ADDR_REG_OFFSET);
  	val = inb_p(address + LM78_DATA_REG_OFFSET);

  	if (val == 0x00 || val == 0x20	/* LM78 */

  	 || val == 0x40			/* LM78-J */
  	 || (val & 0xfe) == 0xc0)	/* LM79 */
  		found = 1;
  
  	if (found)

  		pr_info("Found an %s chip at %#x
  ",

  			val & 0x80 ? "LM79" : "LM78", (int)address);
  
   release:

  	for (port--; port >= address; port--)
  		release_region(port, 1);

  	return found;
  }
  
  static int __init lm78_isa_device_add(unsigned short address)
  {
  	struct resource res = {
  		.start	= address,

  		.end	= address + LM78_EXTENT - 1,

  		.name	= "lm78",
  		.flags	= IORESOURCE_IO,
  	};
  	int err;
  
  	pdev = platform_device_alloc("lm78", address);
  	if (!pdev) {
  		err = -ENOMEM;

  		pr_err("Device allocation failed
  ");

  		goto exit;
  	}
  
  	err = platform_device_add_resources(pdev, &res, 1);
  	if (err) {

  		pr_err("Device resource addition failed (%d)
  ", err);

  		goto exit_device_put;
  	}
  
  	err = platform_device_add(pdev);
  	if (err) {

  		pr_err("Device addition failed (%d)
  ", err);

  		goto exit_device_put;
  	}
  
  	return 0;
  
   exit_device_put:
  	platform_device_put(pdev);
   exit:
  	pdev = NULL;
  	return err;
  }

  static int __init lm78_isa_register(void)

  {

  	int res;

  	if (lm78_isa_found(isa_address)) {
  		res = platform_driver_register(&lm78_isa_driver);
  		if (res)

  			goto exit;

  		/* Sets global pdev as a side effect */
  		res = lm78_isa_device_add(isa_address);
  		if (res)
  			goto exit_unreg_isa_driver;
  	}

  
  	return 0;

  
   exit_unreg_isa_driver:
  	platform_driver_unregister(&lm78_isa_driver);

   exit:
  	return res;

  }

  static void lm78_isa_unregister(void)

  {

  	if (pdev) {
  		platform_device_unregister(pdev);
  		platform_driver_unregister(&lm78_isa_driver);
  	}

  }
  #else /* !CONFIG_ISA */
  
  static int __init lm78_isa_register(void)
  {
  	return 0;
  }
  
  static void lm78_isa_unregister(void)
  {
  }
  #endif /* CONFIG_ISA */
  
  static int __init sm_lm78_init(void)
  {
  	int res;

  	/*
  	 * We register the ISA device first, so that we can skip the
  	 * registration of an I2C interface to the same device.
  	 */

  	res = lm78_isa_register();
  	if (res)
  		goto exit;
  
  	res = i2c_add_driver(&lm78_driver);
  	if (res)
  		goto exit_unreg_isa_device;
  
  	return 0;
  
   exit_unreg_isa_device:
  	lm78_isa_unregister();
   exit:
  	return res;
  }
  
  static void __exit sm_lm78_exit(void)
  {
  	lm78_isa_unregister();

  	i2c_del_driver(&lm78_driver);
  }

  MODULE_AUTHOR("Frodo Looijaard, Jean Delvare <jdelvare@suse.de>");

  MODULE_DESCRIPTION("LM78/LM79 driver");

  MODULE_LICENSE("GPL");
  
  module_init(sm_lm78_init);
  module_exit(sm_lm78_exit);