/*
   * lm83.c - Part of lm_sensors, Linux kernel modules for hardware
   *          monitoring

   * Copyright (C) 2003-2009  Jean Delvare <khali@linux-fr.org>

   *
   * Heavily inspired from the lm78, lm75 and adm1021 drivers. The LM83 is
   * a sensor chip made by National Semiconductor. It reports up to four
   * temperatures (its own plus up to three external ones) with a 1 deg
   * resolution and a 3-4 deg accuracy. Complete datasheet can be obtained
   * from National's website at:
   *   http://www.national.com/pf/LM/LM83.html
   * Since the datasheet omits to give the chip stepping code, I give it
   * here: 0x03 (at register 0xff).
   *

   * Also supports the LM82 temp sensor, which is basically a stripped down
   * model of the LM83.  Datasheet is here:
   * http://www.national.com/pf/LM/LM82.html
   *

   * 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/module.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/jiffies.h>
  #include <linux/i2c.h>

  #include <linux/hwmon-sysfs.h>

  #include <linux/hwmon.h>
  #include <linux/err.h>

  #include <linux/mutex.h>

  #include <linux/sysfs.h>

  
  /*
   * Addresses to scan
   * Address is selected using 2 three-level pins, resulting in 9 possible
   * addresses.
   */

  static const unsigned short normal_i2c[] = {
  	0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, 0x4c, 0x4d, 0x4e, I2C_CLIENT_END };

  enum chips { lm83, lm82 };

  
  /*
   * The LM83 registers
   * Manufacturer ID is 0x01 for National Semiconductor.
   */
  
  #define LM83_REG_R_MAN_ID		0xFE
  #define LM83_REG_R_CHIP_ID		0xFF
  #define LM83_REG_R_CONFIG		0x03
  #define LM83_REG_W_CONFIG		0x09
  #define LM83_REG_R_STATUS1		0x02
  #define LM83_REG_R_STATUS2		0x35
  #define LM83_REG_R_LOCAL_TEMP		0x00
  #define LM83_REG_R_LOCAL_HIGH		0x05
  #define LM83_REG_W_LOCAL_HIGH		0x0B
  #define LM83_REG_R_REMOTE1_TEMP		0x30
  #define LM83_REG_R_REMOTE1_HIGH		0x38
  #define LM83_REG_W_REMOTE1_HIGH		0x50
  #define LM83_REG_R_REMOTE2_TEMP		0x01
  #define LM83_REG_R_REMOTE2_HIGH		0x07
  #define LM83_REG_W_REMOTE2_HIGH		0x0D
  #define LM83_REG_R_REMOTE3_TEMP		0x31
  #define LM83_REG_R_REMOTE3_HIGH		0x3A
  #define LM83_REG_W_REMOTE3_HIGH		0x52
  #define LM83_REG_R_TCRIT		0x42
  #define LM83_REG_W_TCRIT		0x5A
  
  /*
   * Conversions and various macros

   * The LM83 uses signed 8-bit values with LSB = 1 degree Celsius.

   */
  
  #define TEMP_FROM_REG(val)	((val) * 1000)
  #define TEMP_TO_REG(val)	((val) <= -128000 ? -128 : \
  				 (val) >= 127000 ? 127 : \
  				 (val) < 0 ? ((val) - 500) / 1000 : \
  				 ((val) + 500) / 1000)
  
  static const u8 LM83_REG_R_TEMP[] = {
  	LM83_REG_R_LOCAL_TEMP,
  	LM83_REG_R_REMOTE1_TEMP,
  	LM83_REG_R_REMOTE2_TEMP,

  	LM83_REG_R_REMOTE3_TEMP,

  	LM83_REG_R_LOCAL_HIGH,
  	LM83_REG_R_REMOTE1_HIGH,
  	LM83_REG_R_REMOTE2_HIGH,

  	LM83_REG_R_REMOTE3_HIGH,
  	LM83_REG_R_TCRIT,

  };
  
  static const u8 LM83_REG_W_HIGH[] = {
  	LM83_REG_W_LOCAL_HIGH,
  	LM83_REG_W_REMOTE1_HIGH,
  	LM83_REG_W_REMOTE2_HIGH,

  	LM83_REG_W_REMOTE3_HIGH,
  	LM83_REG_W_TCRIT,

  };
  
  /*
   * Functions declaration
   */

  static int lm83_detect(struct i2c_client *new_client,

  		       struct i2c_board_info *info);
  static int lm83_probe(struct i2c_client *client,
  		      const struct i2c_device_id *id);
  static int lm83_remove(struct i2c_client *client);

  static struct lm83_data *lm83_update_device(struct device *dev);
  
  /*
   * Driver data (common to all clients)
   */
   

  static const struct i2c_device_id lm83_id[] = {
  	{ "lm83", lm83 },
  	{ "lm82", lm82 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, lm83_id);

  static struct i2c_driver lm83_driver = {

  	.class		= I2C_CLASS_HWMON,

  	.driver = {

  		.name	= "lm83",
  	},

  	.probe		= lm83_probe,
  	.remove		= lm83_remove,
  	.id_table	= lm83_id,
  	.detect		= lm83_detect,

  	.address_list	= normal_i2c,

  };
  
  /*
   * Client data (each client gets its own)
   */
  
  struct lm83_data {

  	struct device *hwmon_dev;

  	struct mutex update_lock;

  	char valid; /* zero until following fields are valid */
  	unsigned long last_updated; /* in jiffies */
  
  	/* registers values */

  	s8 temp[9];	/* 0..3: input 1-4,
  			   4..7: high limit 1-4,
  			   8   : critical limit */

  	u16 alarms; /* bitvector, combined */
  };
  
  /*
   * Sysfs stuff
   */

  static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
  			 char *buf)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  	struct lm83_data *data = lm83_update_device(dev);
  	return sprintf(buf, "%d
  ", TEMP_FROM_REG(data->temp[attr->index]));

  }

  
  static ssize_t set_temp(struct device *dev, struct device_attribute *devattr,
  			const char *buf, size_t count)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  	struct i2c_client *client = to_i2c_client(dev);
  	struct lm83_data *data = i2c_get_clientdata(client);
  	long val = simple_strtol(buf, NULL, 10);
  	int nr = attr->index;

  	mutex_lock(&data->update_lock);

  	data->temp[nr] = TEMP_TO_REG(val);
  	i2c_smbus_write_byte_data(client, LM83_REG_W_HIGH[nr - 4],
  				  data->temp[nr]);

  	mutex_unlock(&data->update_lock);

  	return count;

  }

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

  {
  	struct lm83_data *data = lm83_update_device(dev);
  	return sprintf(buf, "%d
  ", data->alarms);
  }

  static ssize_t show_alarm(struct device *dev, struct device_attribute
  			  *devattr, char *buf)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  	struct lm83_data *data = lm83_update_device(dev);
  	int bitnr = attr->index;
  
  	return sprintf(buf, "%d
  ", (data->alarms >> bitnr) & 1);
  }

  static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
  static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp, NULL, 1);
  static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_temp, NULL, 2);
  static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, show_temp, NULL, 3);
  static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp,
  	set_temp, 4);
  static SENSOR_DEVICE_ATTR(temp2_max, S_IWUSR | S_IRUGO, show_temp,
  	set_temp, 5);
  static SENSOR_DEVICE_ATTR(temp3_max, S_IWUSR | S_IRUGO, show_temp,
  	set_temp, 6);
  static SENSOR_DEVICE_ATTR(temp4_max, S_IWUSR | S_IRUGO, show_temp,
  	set_temp, 7);
  static SENSOR_DEVICE_ATTR(temp1_crit, S_IRUGO, show_temp, NULL, 8);
  static SENSOR_DEVICE_ATTR(temp2_crit, S_IRUGO, show_temp, NULL, 8);
  static SENSOR_DEVICE_ATTR(temp3_crit, S_IWUSR | S_IRUGO, show_temp,
  	set_temp, 8);
  static SENSOR_DEVICE_ATTR(temp4_crit, S_IRUGO, show_temp, NULL, 8);

  
  /* Individual alarm files */
  static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 0);
  static SENSOR_DEVICE_ATTR(temp3_crit_alarm, S_IRUGO, show_alarm, NULL, 1);

  static SENSOR_DEVICE_ATTR(temp3_fault, S_IRUGO, show_alarm, NULL, 2);

  static SENSOR_DEVICE_ATTR(temp3_max_alarm, S_IRUGO, show_alarm, NULL, 4);
  static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 6);
  static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_alarm, NULL, 8);
  static SENSOR_DEVICE_ATTR(temp4_crit_alarm, S_IRUGO, show_alarm, NULL, 9);

  static SENSOR_DEVICE_ATTR(temp4_fault, S_IRUGO, show_alarm, NULL, 10);

  static SENSOR_DEVICE_ATTR(temp4_max_alarm, S_IRUGO, show_alarm, NULL, 12);

  static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL, 13);

  static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_alarm, NULL, 15);
  /* Raw alarm file for compatibility */

  static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);

  static struct attribute *lm83_attributes[] = {
  	&sensor_dev_attr_temp1_input.dev_attr.attr,
  	&sensor_dev_attr_temp3_input.dev_attr.attr,
  	&sensor_dev_attr_temp1_max.dev_attr.attr,
  	&sensor_dev_attr_temp3_max.dev_attr.attr,
  	&sensor_dev_attr_temp1_crit.dev_attr.attr,
  	&sensor_dev_attr_temp3_crit.dev_attr.attr,
  
  	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp3_crit_alarm.dev_attr.attr,

  	&sensor_dev_attr_temp3_fault.dev_attr.attr,

  	&sensor_dev_attr_temp3_max_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
  	&dev_attr_alarms.attr,
  	NULL
  };
  
  static const struct attribute_group lm83_group = {
  	.attrs = lm83_attributes,
  };
  
  static struct attribute *lm83_attributes_opt[] = {
  	&sensor_dev_attr_temp2_input.dev_attr.attr,
  	&sensor_dev_attr_temp4_input.dev_attr.attr,
  	&sensor_dev_attr_temp2_max.dev_attr.attr,
  	&sensor_dev_attr_temp4_max.dev_attr.attr,
  	&sensor_dev_attr_temp2_crit.dev_attr.attr,
  	&sensor_dev_attr_temp4_crit.dev_attr.attr,
  
  	&sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp4_crit_alarm.dev_attr.attr,

  	&sensor_dev_attr_temp4_fault.dev_attr.attr,

  	&sensor_dev_attr_temp4_max_alarm.dev_attr.attr,

  	&sensor_dev_attr_temp2_fault.dev_attr.attr,

  	&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
  	NULL
  };
  
  static const struct attribute_group lm83_group_opt = {
  	.attrs = lm83_attributes_opt,
  };

  /*
   * Real code
   */

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

  static int lm83_detect(struct i2c_client *new_client,

  		       struct i2c_board_info *info)

  {

  	struct i2c_adapter *adapter = new_client->adapter;

  	const char *name;
  	u8 man_id, chip_id;

  
  	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))

  		return -ENODEV;

  	/* Detection */
  	if ((i2c_smbus_read_byte_data(new_client, LM83_REG_R_STATUS1) & 0xA8) ||
  	    (i2c_smbus_read_byte_data(new_client, LM83_REG_R_STATUS2) & 0x48) ||
  	    (i2c_smbus_read_byte_data(new_client, LM83_REG_R_CONFIG) & 0x41)) {
  		dev_dbg(&adapter->dev, "LM83 detection failed at 0x%02x
  ",
  			new_client->addr);
  		return -ENODEV;

  	}

  	/* Identification */
  	man_id = i2c_smbus_read_byte_data(new_client, LM83_REG_R_MAN_ID);
  	if (man_id != 0x01)	/* National Semiconductor */
  		return -ENODEV;

  	chip_id = i2c_smbus_read_byte_data(new_client, LM83_REG_R_CHIP_ID);
  	switch (chip_id) {
  	case 0x03:

  		name = "lm83";

  		break;
  	case 0x01:

  		name = "lm82";

  		break;
  	default:
  		/* identification failed */
  		dev_info(&adapter->dev,
  			 "Unsupported chip (man_id=0x%02X, chip_id=0x%02X)
  ",
  			 man_id, chip_id);
  		return -ENODEV;

  	}

  	strlcpy(info->type, name, I2C_NAME_SIZE);
  
  	return 0;
  }
  
  static int lm83_probe(struct i2c_client *new_client,
  		      const struct i2c_device_id *id)
  {
  	struct lm83_data *data;
  	int err;
  
  	data = kzalloc(sizeof(struct lm83_data), GFP_KERNEL);
  	if (!data) {
  		err = -ENOMEM;
  		goto exit;
  	}
  
  	i2c_set_clientdata(new_client, data);

  	data->valid = 0;

  	mutex_init(&data->update_lock);

  	/*

  	 * Register sysfs hooks

  	 * The LM82 can only monitor one external diode which is
  	 * at the same register as the LM83 temp3 entry - so we
  	 * declare 1 and 3 common, and then 2 and 4 only for the LM83.
  	 */

  	if ((err = sysfs_create_group(&new_client->dev.kobj, &lm83_group)))

  		goto exit_free;

  	if (id->driver_data == lm83) {

  		if ((err = sysfs_create_group(&new_client->dev.kobj,
  					      &lm83_group_opt)))
  			goto exit_remove_files;
  	}

  	data->hwmon_dev = hwmon_device_register(&new_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(&new_client->dev.kobj, &lm83_group);
  	sysfs_remove_group(&new_client->dev.kobj, &lm83_group_opt);

  exit_free:
  	kfree(data);
  exit:
  	return err;
  }

  static int lm83_remove(struct i2c_client *client)

  {

  	struct lm83_data *data = i2c_get_clientdata(client);

  	hwmon_device_unregister(data->hwmon_dev);

  	sysfs_remove_group(&client->dev.kobj, &lm83_group);
  	sysfs_remove_group(&client->dev.kobj, &lm83_group_opt);

  	kfree(data);

  	return 0;
  }
  
  static struct lm83_data *lm83_update_device(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct lm83_data *data = i2c_get_clientdata(client);

  	mutex_lock(&data->update_lock);

  
  	if (time_after(jiffies, data->last_updated + HZ * 2) || !data->valid) {
  		int nr;
  
  		dev_dbg(&client->dev, "Updating lm83 data.
  ");

  		for (nr = 0; nr < 9; nr++) {
  			data->temp[nr] =

  			    i2c_smbus_read_byte_data(client,
  			    LM83_REG_R_TEMP[nr]);

  		}

  		data->alarms =
  		    i2c_smbus_read_byte_data(client, LM83_REG_R_STATUS1)
  		    + (i2c_smbus_read_byte_data(client, LM83_REG_R_STATUS2)
  		    << 8);
  
  		data->last_updated = jiffies;
  		data->valid = 1;
  	}

  	mutex_unlock(&data->update_lock);

  
  	return data;
  }
  
  static int __init sensors_lm83_init(void)
  {
  	return i2c_add_driver(&lm83_driver);
  }
  
  static void __exit sensors_lm83_exit(void)
  {
  	i2c_del_driver(&lm83_driver);
  }
  
  MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
  MODULE_DESCRIPTION("LM83 driver");
  MODULE_LICENSE("GPL");
  
  module_init(sensors_lm83_init);
  module_exit(sensors_lm83_exit);