/*
   * lm90.c - Part of lm_sensors, Linux kernel modules for hardware
   *          monitoring

   * Copyright (C) 2003-2010  Jean Delvare <khali@linux-fr.org>

   *
   * Based on the lm83 driver. The LM90 is a sensor chip made by National
   * Semiconductor. It reports up to two temperatures (its own plus up to
   * one external one) with a 0.125 deg resolution (1 deg for local

   * temperature) and a 3-4 deg accuracy.

   *
   * This driver also supports the LM89 and LM99, two other sensor chips
   * made by National Semiconductor. Both have an increased remote
   * temperature measurement accuracy (1 degree), and the LM99
   * additionally shifts remote temperatures (measured and limits) by 16

   * degrees, which allows for higher temperatures measurement.

   * Note that there is no way to differentiate between both chips.

   * When device is auto-detected, the driver will assume an LM99.

   *
   * This driver also supports the LM86, another sensor chip made by
   * National Semiconductor. It is exactly similar to the LM90 except it
   * has a higher accuracy.

   *
   * This driver also supports the ADM1032, a sensor chip made by Analog
   * Devices. That chip is similar to the LM90, with a few differences

   * that are not handled by this driver. Among others, it has a higher
   * accuracy than the LM90, much like the LM86 does.

   *
   * This driver also supports the MAX6657, MAX6658 and MAX6659 sensor

   * chips made by Maxim. These chips are similar to the LM86.

   * Note that there is no easy way to differentiate between the three

   * variants. We use the device address to detect MAX6659, which will result
   * in a detection as max6657 if it is on address 0x4c. The extra address
   * and features of the MAX6659 are only supported if the chip is configured
   * explicitly as max6659, or if its address is not 0x4c.
   * These chips lack the remote temperature offset feature.

   *

   * This driver also supports the MAX6646, MAX6647, MAX6648, MAX6649 and
   * MAX6692 chips made by Maxim.  These are again similar to the LM86,
   * but they use unsigned temperature values and can report temperatures
   * from 0 to 145 degrees.

   *

   * This driver also supports the MAX6680 and MAX6681, two other sensor
   * chips made by Maxim. These are quite similar to the other Maxim

   * chips. The MAX6680 and MAX6681 only differ in the pinout so they can
   * be treated identically.

   *

   * This driver also supports the MAX6695 and MAX6696, two other sensor
   * chips made by Maxim. These are also quite similar to other Maxim
   * chips, but support three temperature sensors instead of two. MAX6695
   * and MAX6696 only differ in the pinout so they can be treated identically.
   *

   * This driver also supports ADT7461 and ADT7461A from Analog Devices as well as
   * NCT1008 from ON Semiconductor. The chips are supported in both compatibility
   * and extended mode. They are mostly compatible with LM90 except for a data
   * format difference for the temperature value registers.

   *

   * This driver also supports the SA56004 from Philips. This device is
   * pin-compatible with the LM86, the ED/EDP parts are also address-compatible.
   *

   * Since the LM90 was the first chipset supported by this driver, most
   * comments will refer to this chipset, but are actually general and
   * concern all supported chipsets, unless mentioned otherwise.
   *
   * 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 fully defined internally and cannot be changed except for

   * MAX6659, MAX6680 and MAX6681.

   * LM86, LM89, LM90, LM99, ADM1032, ADM1032-1, ADT7461, ADT7461A, MAX6649,
   * MAX6657, MAX6658, NCT1008 and W83L771 have address 0x4c.
   * ADM1032-2, ADT7461-2, ADT7461A-2, LM89-1, LM99-1, MAX6646, and NCT1008D
   * have address 0x4d.

   * MAX6647 has address 0x4e.

   * MAX6659 can have address 0x4c, 0x4d or 0x4e.

   * MAX6680 and MAX6681 can have address 0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b,
   * 0x4c, 0x4d or 0x4e.

   * SA56004 can have address 0x48 through 0x4F.

   */

  static const unsigned short normal_i2c[] = {

  	0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  	0x4d, 0x4e, 0x4f, I2C_CLIENT_END };

  enum chips { lm90, adm1032, lm99, lm86, max6657, max6659, adt7461, max6680,

  	max6646, w83l771, max6696, sa56004 };

  
  /*
   * The LM90 registers
   */
  
  #define LM90_REG_R_MAN_ID		0xFE
  #define LM90_REG_R_CHIP_ID		0xFF
  #define LM90_REG_R_CONFIG1		0x03
  #define LM90_REG_W_CONFIG1		0x09
  #define LM90_REG_R_CONFIG2		0xBF
  #define LM90_REG_W_CONFIG2		0xBF
  #define LM90_REG_R_CONVRATE		0x04
  #define LM90_REG_W_CONVRATE		0x0A
  #define LM90_REG_R_STATUS		0x02
  #define LM90_REG_R_LOCAL_TEMP		0x00
  #define LM90_REG_R_LOCAL_HIGH		0x05
  #define LM90_REG_W_LOCAL_HIGH		0x0B
  #define LM90_REG_R_LOCAL_LOW		0x06
  #define LM90_REG_W_LOCAL_LOW		0x0C
  #define LM90_REG_R_LOCAL_CRIT		0x20
  #define LM90_REG_W_LOCAL_CRIT		0x20
  #define LM90_REG_R_REMOTE_TEMPH		0x01
  #define LM90_REG_R_REMOTE_TEMPL		0x10
  #define LM90_REG_R_REMOTE_OFFSH		0x11
  #define LM90_REG_W_REMOTE_OFFSH		0x11
  #define LM90_REG_R_REMOTE_OFFSL		0x12
  #define LM90_REG_W_REMOTE_OFFSL		0x12
  #define LM90_REG_R_REMOTE_HIGHH		0x07
  #define LM90_REG_W_REMOTE_HIGHH		0x0D
  #define LM90_REG_R_REMOTE_HIGHL		0x13
  #define LM90_REG_W_REMOTE_HIGHL		0x13
  #define LM90_REG_R_REMOTE_LOWH		0x08
  #define LM90_REG_W_REMOTE_LOWH		0x0E
  #define LM90_REG_R_REMOTE_LOWL		0x14
  #define LM90_REG_W_REMOTE_LOWL		0x14
  #define LM90_REG_R_REMOTE_CRIT		0x19
  #define LM90_REG_W_REMOTE_CRIT		0x19
  #define LM90_REG_R_TCRIT_HYST		0x21
  #define LM90_REG_W_TCRIT_HYST		0x21

  /* MAX6646/6647/6649/6657/6658/6659/6695/6696 registers */

  
  #define MAX6657_REG_R_LOCAL_TEMPL	0x11

  #define MAX6696_REG_R_STATUS2		0x12

  #define MAX6659_REG_R_REMOTE_EMERG	0x16
  #define MAX6659_REG_W_REMOTE_EMERG	0x16
  #define MAX6659_REG_R_LOCAL_EMERG	0x17
  #define MAX6659_REG_W_LOCAL_EMERG	0x17

  /*  SA56004 registers */
  
  #define SA56004_REG_R_LOCAL_TEMPL 0x22

  #define LM90_DEF_CONVRATE_RVAL	6	/* Def conversion rate register value */
  #define LM90_MAX_CONVRATE_MS	16000	/* Maximum conversion rate in ms */

  /*

   * Device flags
   */

  #define LM90_FLAG_ADT7461_EXT	(1 << 0) /* ADT7461 extended mode	*/
  /* Device features */
  #define LM90_HAVE_OFFSET	(1 << 1) /* temperature offset register	*/

  #define LM90_HAVE_REM_LIMIT_EXT	(1 << 3) /* extended remote limit	*/

  #define LM90_HAVE_EMERGENCY	(1 << 4) /* 3rd upper (emergency) limit	*/

  #define LM90_HAVE_EMERGENCY_ALARM (1 << 5)/* emergency alarm		*/
  #define LM90_HAVE_TEMP3		(1 << 6) /* 3rd temperature sensor	*/

  #define LM90_HAVE_BROKEN_ALERT	(1 << 7) /* Broken alert		*/

  
  /*

   * Driver data (common to all clients)
   */

  static const struct i2c_device_id lm90_id[] = {
  	{ "adm1032", adm1032 },
  	{ "adt7461", adt7461 },

  	{ "adt7461a", adt7461 },

  	{ "lm90", lm90 },
  	{ "lm86", lm86 },

  	{ "lm89", lm86 },
  	{ "lm99", lm99 },

  	{ "max6646", max6646 },
  	{ "max6647", max6646 },
  	{ "max6649", max6646 },

  	{ "max6657", max6657 },
  	{ "max6658", max6657 },

  	{ "max6659", max6659 },

  	{ "max6680", max6680 },
  	{ "max6681", max6680 },

  	{ "max6695", max6696 },
  	{ "max6696", max6696 },

  	{ "nct1008", adt7461 },

  	{ "w83l771", w83l771 },

  	{ "sa56004", sa56004 },

  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, lm90_id);

  /*

   * chip type specific parameters
   */
  struct lm90_params {
  	u32 flags;		/* Capabilities */
  	u16 alert_alarms;	/* Which alarm bits trigger ALERT# */
  				/* Upper 8 bits for max6695/96 */

  	u8 max_convrate;	/* Maximum conversion rate register value */

  	u8 reg_local_ext;	/* Extended local temp register (optional) */

  };
  
  static const struct lm90_params lm90_params[] = {
  	[adm1032] = {

  		.flags = LM90_HAVE_OFFSET | LM90_HAVE_REM_LIMIT_EXT
  		  | LM90_HAVE_BROKEN_ALERT,

  		.alert_alarms = 0x7c,

  		.max_convrate = 10,

  	},
  	[adt7461] = {

  		.flags = LM90_HAVE_OFFSET | LM90_HAVE_REM_LIMIT_EXT
  		  | LM90_HAVE_BROKEN_ALERT,

  		.alert_alarms = 0x7c,

  		.max_convrate = 10,

  	},
  	[lm86] = {
  		.flags = LM90_HAVE_OFFSET | LM90_HAVE_REM_LIMIT_EXT,
  		.alert_alarms = 0x7b,

  		.max_convrate = 9,

  	},
  	[lm90] = {
  		.flags = LM90_HAVE_OFFSET | LM90_HAVE_REM_LIMIT_EXT,
  		.alert_alarms = 0x7b,

  		.max_convrate = 9,

  	},
  	[lm99] = {
  		.flags = LM90_HAVE_OFFSET | LM90_HAVE_REM_LIMIT_EXT,
  		.alert_alarms = 0x7b,

  		.max_convrate = 9,

  	},
  	[max6646] = {

  		.alert_alarms = 0x7c,

  		.max_convrate = 6,

  		.reg_local_ext = MAX6657_REG_R_LOCAL_TEMPL,

  	},
  	[max6657] = {

  		.alert_alarms = 0x7c,

  		.max_convrate = 8,

  		.reg_local_ext = MAX6657_REG_R_LOCAL_TEMPL,

  	},
  	[max6659] = {

  		.flags = LM90_HAVE_EMERGENCY,

  		.alert_alarms = 0x7c,

  		.max_convrate = 8,

  		.reg_local_ext = MAX6657_REG_R_LOCAL_TEMPL,

  	},
  	[max6680] = {
  		.flags = LM90_HAVE_OFFSET,
  		.alert_alarms = 0x7c,

  		.max_convrate = 7,

  	},
  	[max6696] = {

  		.flags = LM90_HAVE_EMERGENCY

  		  | LM90_HAVE_EMERGENCY_ALARM | LM90_HAVE_TEMP3,
  		.alert_alarms = 0x187c,

  		.max_convrate = 6,

  		.reg_local_ext = MAX6657_REG_R_LOCAL_TEMPL,

  	},
  	[w83l771] = {
  		.flags = LM90_HAVE_OFFSET | LM90_HAVE_REM_LIMIT_EXT,
  		.alert_alarms = 0x7c,

  		.max_convrate = 8,

  	},

  	[sa56004] = {

  		.flags = LM90_HAVE_OFFSET | LM90_HAVE_REM_LIMIT_EXT,

  		.alert_alarms = 0x7b,
  		.max_convrate = 9,
  		.reg_local_ext = SA56004_REG_R_LOCAL_TEMPL,
  	},

  };
  
  /*

   * Client data (each client gets its own)
   */
  
  struct lm90_data {

  	struct device *hwmon_dev;

  	struct mutex update_lock;

  	char valid; /* zero until following fields are valid */
  	unsigned long last_updated; /* in jiffies */
  	int kind;

  	u32 flags;

  	int update_interval;	/* in milliseconds */

  	u8 config_orig;		/* Original configuration register value */

  	u8 convrate_orig;	/* Original conversion rate register value */

  	u16 alert_alarms;	/* Which alarm bits trigger ALERT# */
  				/* Upper 8 bits for max6695/96 */

  	u8 max_convrate;	/* Maximum conversion rate */

  	u8 reg_local_ext;	/* local extension register offset */

  	/* registers values */

  	s8 temp8[8];	/* 0: local low limit

  			   1: local high limit
  			   2: local critical limit

  			   3: remote critical limit

  			   4: local emergency limit (max6659 and max6695/96)
  			   5: remote emergency limit (max6659 and max6695/96)
  			   6: remote 2 critical limit (max6695/96 only)
  			   7: remote 2 emergency limit (max6695/96 only) */
  	s16 temp11[8];	/* 0: remote input

  			   1: remote low limit

  			   2: remote high limit

  			   3: remote offset (except max6646, max6657/58/59,
  					     and max6695/96)
  			   4: local input
  			   5: remote 2 input (max6695/96 only)
  			   6: remote 2 low limit (max6695/96 only)
  			   7: remote 2 high limit (ma6695/96 only) */

  	u8 temp_hyst;

  	u16 alarms; /* bitvector (upper 8 bits for max6695/96) */

  };
  
  /*

   * Support functions
   */
  
  /*
   * The ADM1032 supports PEC but not on write byte transactions, so we need
   * to explicitly ask for a transaction without PEC.
   */
  static inline s32 adm1032_write_byte(struct i2c_client *client, u8 value)
  {
  	return i2c_smbus_xfer(client->adapter, client->addr,
  			      client->flags & ~I2C_CLIENT_PEC,
  			      I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
  }
  
  /*
   * It is assumed that client->update_lock is held (unless we are in
   * detection or initialization steps). This matters when PEC is enabled,
   * because we don't want the address pointer to change between the write
   * byte and the read byte transactions.
   */
  static int lm90_read_reg(struct i2c_client *client, u8 reg, u8 *value)
  {
  	int err;
  
  	if (client->flags & I2C_CLIENT_PEC) {
  		err = adm1032_write_byte(client, reg);
  		if (err >= 0)
  			err = i2c_smbus_read_byte(client);
  	} else
  		err = i2c_smbus_read_byte_data(client, reg);
  
  	if (err < 0) {
  		dev_warn(&client->dev, "Register %#02x read failed (%d)
  ",
  			 reg, err);
  		return err;
  	}
  	*value = err;
  
  	return 0;
  }
  
  static int lm90_read16(struct i2c_client *client, u8 regh, u8 regl, u16 *value)
  {
  	int err;
  	u8 oldh, newh, l;
  
  	/*
  	 * There is a trick here. We have to read two registers to have the
  	 * sensor temperature, but we have to beware a conversion could occur

  	 * between the readings. The datasheet says we should either use

  	 * the one-shot conversion register, which we don't want to do
  	 * (disables hardware monitoring) or monitor the busy bit, which is
  	 * impossible (we can't read the values and monitor that bit at the
  	 * exact same time). So the solution used here is to read the high
  	 * byte once, then the low byte, then the high byte again. If the new
  	 * high byte matches the old one, then we have a valid reading. Else
  	 * we have to read the low byte again, and now we believe we have a
  	 * correct reading.
  	 */
  	if ((err = lm90_read_reg(client, regh, &oldh))
  	 || (err = lm90_read_reg(client, regl, &l))
  	 || (err = lm90_read_reg(client, regh, &newh)))
  		return err;
  	if (oldh != newh) {
  		err = lm90_read_reg(client, regl, &l);
  		if (err)
  			return err;
  	}
  	*value = (newh << 8) | l;
  
  	return 0;
  }
  
  /*
   * client->update_lock must be held when calling this function (unless we are
   * in detection or initialization steps), and while a remote channel other
   * than channel 0 is selected. Also, calling code must make sure to re-select
   * external channel 0 before releasing the lock. This is necessary because
   * various registers have different meanings as a result of selecting a
   * non-default remote channel.
   */
  static inline void lm90_select_remote_channel(struct i2c_client *client,
  					      struct lm90_data *data,
  					      int channel)
  {
  	u8 config;
  
  	if (data->kind == max6696) {
  		lm90_read_reg(client, LM90_REG_R_CONFIG1, &config);
  		config &= ~0x08;
  		if (channel)
  			config |= 0x08;
  		i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
  					  config);
  	}
  }

  /*
   * Set conversion rate.
   * client->update_lock must be held when calling this function (unless we are
   * in detection or initialization steps).
   */
  static void lm90_set_convrate(struct i2c_client *client, struct lm90_data *data,
  			      unsigned int interval)
  {
  	int i;
  	unsigned int update_interval;
  
  	/* Shift calculations to avoid rounding errors */
  	interval <<= 6;
  
  	/* find the nearest update rate */
  	for (i = 0, update_interval = LM90_MAX_CONVRATE_MS << 6;
  	     i < data->max_convrate; i++, update_interval >>= 1)
  		if (interval >= update_interval * 3 / 4)
  			break;
  
  	i2c_smbus_write_byte_data(client, LM90_REG_W_CONVRATE, i);
  	data->update_interval = DIV_ROUND_CLOSEST(update_interval, 64);
  }

  static struct lm90_data *lm90_update_device(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct lm90_data *data = i2c_get_clientdata(client);

  	unsigned long next_update;

  
  	mutex_lock(&data->update_lock);

  	next_update = data->last_updated
  	  + msecs_to_jiffies(data->update_interval) + 1;
  	if (time_after(jiffies, next_update) || !data->valid) {

  		u8 h, l;
  		u8 alarms;
  
  		dev_dbg(&client->dev, "Updating lm90 data.
  ");
  		lm90_read_reg(client, LM90_REG_R_LOCAL_LOW, &data->temp8[0]);
  		lm90_read_reg(client, LM90_REG_R_LOCAL_HIGH, &data->temp8[1]);
  		lm90_read_reg(client, LM90_REG_R_LOCAL_CRIT, &data->temp8[2]);
  		lm90_read_reg(client, LM90_REG_R_REMOTE_CRIT, &data->temp8[3]);
  		lm90_read_reg(client, LM90_REG_R_TCRIT_HYST, &data->temp_hyst);

  		if (data->reg_local_ext) {

  			lm90_read16(client, LM90_REG_R_LOCAL_TEMP,

  				    data->reg_local_ext,

  				    &data->temp11[4]);
  		} else {
  			if (lm90_read_reg(client, LM90_REG_R_LOCAL_TEMP,
  					  &h) == 0)
  				data->temp11[4] = h << 8;
  		}
  		lm90_read16(client, LM90_REG_R_REMOTE_TEMPH,
  			    LM90_REG_R_REMOTE_TEMPL, &data->temp11[0]);
  
  		if (lm90_read_reg(client, LM90_REG_R_REMOTE_LOWH, &h) == 0) {
  			data->temp11[1] = h << 8;
  			if ((data->flags & LM90_HAVE_REM_LIMIT_EXT)
  			 && lm90_read_reg(client, LM90_REG_R_REMOTE_LOWL,
  					  &l) == 0)
  				data->temp11[1] |= l;
  		}
  		if (lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHH, &h) == 0) {
  			data->temp11[2] = h << 8;
  			if ((data->flags & LM90_HAVE_REM_LIMIT_EXT)
  			 && lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHL,
  					  &l) == 0)
  				data->temp11[2] |= l;
  		}
  
  		if (data->flags & LM90_HAVE_OFFSET) {
  			if (lm90_read_reg(client, LM90_REG_R_REMOTE_OFFSH,
  					  &h) == 0
  			 && lm90_read_reg(client, LM90_REG_R_REMOTE_OFFSL,
  					  &l) == 0)
  				data->temp11[3] = (h << 8) | l;
  		}
  		if (data->flags & LM90_HAVE_EMERGENCY) {
  			lm90_read_reg(client, MAX6659_REG_R_LOCAL_EMERG,
  				      &data->temp8[4]);
  			lm90_read_reg(client, MAX6659_REG_R_REMOTE_EMERG,
  				      &data->temp8[5]);
  		}
  		lm90_read_reg(client, LM90_REG_R_STATUS, &alarms);
  		data->alarms = alarms;	/* save as 16 bit value */
  
  		if (data->kind == max6696) {
  			lm90_select_remote_channel(client, data, 1);
  			lm90_read_reg(client, LM90_REG_R_REMOTE_CRIT,
  				      &data->temp8[6]);
  			lm90_read_reg(client, MAX6659_REG_R_REMOTE_EMERG,
  				      &data->temp8[7]);
  			lm90_read16(client, LM90_REG_R_REMOTE_TEMPH,
  				    LM90_REG_R_REMOTE_TEMPL, &data->temp11[5]);
  			if (!lm90_read_reg(client, LM90_REG_R_REMOTE_LOWH, &h))
  				data->temp11[6] = h << 8;
  			if (!lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHH, &h))
  				data->temp11[7] = h << 8;
  			lm90_select_remote_channel(client, data, 0);
  
  			if (!lm90_read_reg(client, MAX6696_REG_R_STATUS2,
  					   &alarms))
  				data->alarms |= alarms << 8;
  		}
  
  		/* Re-enable ALERT# output if it was originally enabled and
  		 * relevant alarms are all clear */
  		if ((data->config_orig & 0x80) == 0
  		 && (data->alarms & data->alert_alarms) == 0) {
  			u8 config;
  
  			lm90_read_reg(client, LM90_REG_R_CONFIG1, &config);
  			if (config & 0x80) {
  				dev_dbg(&client->dev, "Re-enabling ALERT#
  ");
  				i2c_smbus_write_byte_data(client,
  							  LM90_REG_W_CONFIG1,
  							  config & ~0x80);
  			}
  		}
  
  		data->last_updated = jiffies;
  		data->valid = 1;
  	}
  
  	mutex_unlock(&data->update_lock);
  
  	return data;
  }
  
  /*

   * Conversions
   * For local temperatures and limits, critical limits and the hysteresis
   * value, the LM90 uses signed 8-bit values with LSB = 1 degree Celsius.
   * For remote temperatures and limits, it uses signed 11-bit values with

   * LSB = 0.125 degree Celsius, left-justified in 16-bit registers.  Some
   * Maxim chips use unsigned values.

   */

  static inline int temp_from_s8(s8 val)

  {
  	return val * 1000;
  }

  static inline int temp_from_u8(u8 val)
  {
  	return val * 1000;
  }

  static inline int temp_from_s16(s16 val)

  {
  	return val / 32 * 125;
  }

  static inline int temp_from_u16(u16 val)
  {
  	return val / 32 * 125;
  }

  static s8 temp_to_s8(long val)

  {
  	if (val <= -128000)
  		return -128;
  	if (val >= 127000)
  		return 127;
  	if (val < 0)
  		return (val - 500) / 1000;
  	return (val + 500) / 1000;
  }

  static u8 temp_to_u8(long val)
  {
  	if (val <= 0)
  		return 0;
  	if (val >= 255000)
  		return 255;
  	return (val + 500) / 1000;
  }

  static s16 temp_to_s16(long val)

  {
  	if (val <= -128000)
  		return 0x8000;
  	if (val >= 127875)
  		return 0x7FE0;
  	if (val < 0)
  		return (val - 62) / 125 * 32;
  	return (val + 62) / 125 * 32;
  }
  
  static u8 hyst_to_reg(long val)
  {
  	if (val <= 0)
  		return 0;
  	if (val >= 30500)
  		return 31;
  	return (val + 500) / 1000;
  }
  
  /*

   * ADT7461 in compatibility mode is almost identical to LM90 except that
   * attempts to write values that are outside the range 0 < temp < 127 are
   * treated as the boundary value.
   *
   * ADT7461 in "extended mode" operation uses unsigned integers offset by
   * 64 (e.g., 0 -> -64 degC).  The range is restricted to -64..191 degC.

   */

  static inline int temp_from_u8_adt7461(struct lm90_data *data, u8 val)

  {

  	if (data->flags & LM90_FLAG_ADT7461_EXT)
  		return (val - 64) * 1000;
  	else

  		return temp_from_s8(val);

  }

  static inline int temp_from_u16_adt7461(struct lm90_data *data, u16 val)

  {

  	if (data->flags & LM90_FLAG_ADT7461_EXT)
  		return (val - 0x4000) / 64 * 250;
  	else

  		return temp_from_s16(val);

  }

  static u8 temp_to_u8_adt7461(struct lm90_data *data, long val)

  {
  	if (data->flags & LM90_FLAG_ADT7461_EXT) {
  		if (val <= -64000)
  			return 0;
  		if (val >= 191000)
  			return 0xFF;
  		return (val + 500 + 64000) / 1000;
  	} else {
  		if (val <= 0)
  			return 0;
  		if (val >= 127000)
  			return 127;
  		return (val + 500) / 1000;
  	}
  }

  static u16 temp_to_u16_adt7461(struct lm90_data *data, long val)

  {
  	if (data->flags & LM90_FLAG_ADT7461_EXT) {
  		if (val <= -64000)
  			return 0;
  		if (val >= 191750)
  			return 0xFFC0;
  		return (val + 64000 + 125) / 250 * 64;
  	} else {
  		if (val <= 0)
  			return 0;
  		if (val >= 127750)
  			return 0x7FC0;
  		return (val + 125) / 250 * 64;
  	}

  }
  
  /*

   * Sysfs stuff
   */

  static ssize_t show_temp8(struct device *dev, struct device_attribute *devattr,
  			  char *buf)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  	struct lm90_data *data = lm90_update_device(dev);

  	int temp;
  
  	if (data->kind == adt7461)

  		temp = temp_from_u8_adt7461(data, data->temp8[attr->index]);

  	else if (data->kind == max6646)
  		temp = temp_from_u8(data->temp8[attr->index]);

  	else

  		temp = temp_from_s8(data->temp8[attr->index]);

  	/* +16 degrees offset for temp2 for the LM99 */
  	if (data->kind == lm99 && attr->index == 3)
  		temp += 16000;

  	return sprintf(buf, "%d
  ", temp);

  }
  
  static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
  			 const char *buf, size_t count)
  {

  	static const u8 reg[8] = {

  		LM90_REG_W_LOCAL_LOW,
  		LM90_REG_W_LOCAL_HIGH,
  		LM90_REG_W_LOCAL_CRIT,
  		LM90_REG_W_REMOTE_CRIT,

  		MAX6659_REG_W_LOCAL_EMERG,
  		MAX6659_REG_W_REMOTE_EMERG,

  		LM90_REG_W_REMOTE_CRIT,
  		MAX6659_REG_W_REMOTE_EMERG,

  	};
  
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  	struct i2c_client *client = to_i2c_client(dev);
  	struct lm90_data *data = i2c_get_clientdata(client);

  	int nr = attr->index;

  	long val;
  	int err;

  	err = kstrtol(buf, 10, &val);

  	if (err < 0)
  		return err;

  	/* +16 degrees offset for temp2 for the LM99 */
  	if (data->kind == lm99 && attr->index == 3)
  		val -= 16000;

  	mutex_lock(&data->update_lock);

  	if (data->kind == adt7461)

  		data->temp8[nr] = temp_to_u8_adt7461(data, val);

  	else if (data->kind == max6646)
  		data->temp8[nr] = temp_to_u8(val);

  	else

  		data->temp8[nr] = temp_to_s8(val);

  
  	lm90_select_remote_channel(client, data, nr >= 6);

  	i2c_smbus_write_byte_data(client, reg[nr], data->temp8[nr]);

  	lm90_select_remote_channel(client, data, 0);

  	mutex_unlock(&data->update_lock);

  	return count;

  }

  
  static ssize_t show_temp11(struct device *dev, struct device_attribute *devattr,
  			   char *buf)
  {

  	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);

  	struct lm90_data *data = lm90_update_device(dev);

  	int temp;
  
  	if (data->kind == adt7461)

  		temp = temp_from_u16_adt7461(data, data->temp11[attr->index]);

  	else if (data->kind == max6646)
  		temp = temp_from_u16(data->temp11[attr->index]);

  	else

  		temp = temp_from_s16(data->temp11[attr->index]);

  	/* +16 degrees offset for temp2 for the LM99 */
  	if (data->kind == lm99 &&  attr->index <= 2)
  		temp += 16000;

  	return sprintf(buf, "%d
  ", temp);

  }

  
  static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
  			  const char *buf, size_t count)
  {

  	struct {
  		u8 high;
  		u8 low;

  		int channel;
  	} reg[5] = {
  		{ LM90_REG_W_REMOTE_LOWH, LM90_REG_W_REMOTE_LOWL, 0 },
  		{ LM90_REG_W_REMOTE_HIGHH, LM90_REG_W_REMOTE_HIGHL, 0 },
  		{ LM90_REG_W_REMOTE_OFFSH, LM90_REG_W_REMOTE_OFFSL, 0 },
  		{ LM90_REG_W_REMOTE_LOWH, LM90_REG_W_REMOTE_LOWL, 1 },
  		{ LM90_REG_W_REMOTE_HIGHH, LM90_REG_W_REMOTE_HIGHL, 1 }

  	};

  	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);

  	struct i2c_client *client = to_i2c_client(dev);
  	struct lm90_data *data = i2c_get_clientdata(client);

  	int nr = attr->nr;
  	int index = attr->index;

  	long val;
  	int err;

  	err = kstrtol(buf, 10, &val);

  	if (err < 0)
  		return err;

  	/* +16 degrees offset for temp2 for the LM99 */

  	if (data->kind == lm99 && index <= 2)

  		val -= 16000;

  	mutex_lock(&data->update_lock);

  	if (data->kind == adt7461)

  		data->temp11[index] = temp_to_u16_adt7461(data, val);

  	else if (data->kind == max6646)

  		data->temp11[index] = temp_to_u8(val) << 8;

  	else if (data->flags & LM90_HAVE_REM_LIMIT_EXT)

  		data->temp11[index] = temp_to_s16(val);

  	else

  		data->temp11[index] = temp_to_s8(val) << 8;

  	lm90_select_remote_channel(client, data, reg[nr].channel);

  	i2c_smbus_write_byte_data(client, reg[nr].high,
  				  data->temp11[index] >> 8);

  	if (data->flags & LM90_HAVE_REM_LIMIT_EXT)

  		i2c_smbus_write_byte_data(client, reg[nr].low,
  					  data->temp11[index] & 0xff);

  	lm90_select_remote_channel(client, data, 0);

  	mutex_unlock(&data->update_lock);

  	return count;

  }

  static ssize_t show_temphyst(struct device *dev,
  			     struct device_attribute *devattr,

  			     char *buf)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  	struct lm90_data *data = lm90_update_device(dev);

  	int temp;
  
  	if (data->kind == adt7461)

  		temp = temp_from_u8_adt7461(data, data->temp8[attr->index]);

  	else if (data->kind == max6646)
  		temp = temp_from_u8(data->temp8[attr->index]);

  	else

  		temp = temp_from_s8(data->temp8[attr->index]);

  	/* +16 degrees offset for temp2 for the LM99 */
  	if (data->kind == lm99 && attr->index == 3)
  		temp += 16000;

  	return sprintf(buf, "%d
  ", temp - temp_from_s8(data->temp_hyst));

  }

  static ssize_t set_temphyst(struct device *dev, struct device_attribute *dummy,
  			    const char *buf, size_t count)

  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct lm90_data *data = i2c_get_clientdata(client);

  	long val;
  	int err;

  	int temp;

  	err = kstrtol(buf, 10, &val);

  	if (err < 0)
  		return err;

  	mutex_lock(&data->update_lock);

  	if (data->kind == adt7461)
  		temp = temp_from_u8_adt7461(data, data->temp8[2]);
  	else if (data->kind == max6646)
  		temp = temp_from_u8(data->temp8[2]);
  	else
  		temp = temp_from_s8(data->temp8[2]);
  
  	data->temp_hyst = hyst_to_reg(temp - val);

  	i2c_smbus_write_byte_data(client, LM90_REG_W_TCRIT_HYST,

  				  data->temp_hyst);

  	mutex_unlock(&data->update_lock);

  	return count;
  }

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

  {
  	struct lm90_data *data = lm90_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 lm90_data *data = lm90_update_device(dev);
  	int bitnr = attr->index;
  
  	return sprintf(buf, "%d
  ", (data->alarms >> bitnr) & 1);
  }

  static ssize_t show_update_interval(struct device *dev,
  				    struct device_attribute *attr, char *buf)
  {
  	struct lm90_data *data = dev_get_drvdata(dev);
  
  	return sprintf(buf, "%u
  ", data->update_interval);
  }
  
  static ssize_t set_update_interval(struct device *dev,
  				   struct device_attribute *attr,
  				   const char *buf, size_t count)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct lm90_data *data = i2c_get_clientdata(client);
  	unsigned long val;
  	int err;

  	err = kstrtoul(buf, 10, &val);

  	if (err)
  		return err;
  
  	mutex_lock(&data->update_lock);

  	lm90_set_convrate(client, data, SENSORS_LIMIT(val, 0, 100000));

  	mutex_unlock(&data->update_lock);
  
  	return count;
  }

  static SENSOR_DEVICE_ATTR_2(temp1_input, S_IRUGO, show_temp11, NULL, 0, 4);
  static SENSOR_DEVICE_ATTR_2(temp2_input, S_IRUGO, show_temp11, NULL, 0, 0);

  static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp8,

  	set_temp8, 0);

  static SENSOR_DEVICE_ATTR_2(temp2_min, S_IWUSR | S_IRUGO, show_temp11,
  	set_temp11, 0, 1);

  static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp8,

  	set_temp8, 1);

  static SENSOR_DEVICE_ATTR_2(temp2_max, S_IWUSR | S_IRUGO, show_temp11,
  	set_temp11, 1, 2);

  static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp8,

  	set_temp8, 2);

  static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_temp8,

  	set_temp8, 3);

  static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temphyst,

  	set_temphyst, 2);
  static SENSOR_DEVICE_ATTR(temp2_crit_hyst, S_IRUGO, show_temphyst, NULL, 3);

  static SENSOR_DEVICE_ATTR_2(temp2_offset, S_IWUSR | S_IRUGO, show_temp11,
  	set_temp11, 2, 3);

  
  /* Individual alarm files */
  static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 0);
  static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_alarm, NULL, 1);

  static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL, 2);

  static SENSOR_DEVICE_ATTR(temp2_min_alarm, S_IRUGO, show_alarm, NULL, 3);
  static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_alarm, NULL, 4);
  static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 5);
  static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 6);
  /* Raw alarm file for compatibility */

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

  static DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR, show_update_interval,
  		   set_update_interval);

  static struct attribute *lm90_attributes[] = {
  	&sensor_dev_attr_temp1_input.dev_attr.attr,
  	&sensor_dev_attr_temp2_input.dev_attr.attr,
  	&sensor_dev_attr_temp1_min.dev_attr.attr,
  	&sensor_dev_attr_temp2_min.dev_attr.attr,
  	&sensor_dev_attr_temp1_max.dev_attr.attr,
  	&sensor_dev_attr_temp2_max.dev_attr.attr,
  	&sensor_dev_attr_temp1_crit.dev_attr.attr,
  	&sensor_dev_attr_temp2_crit.dev_attr.attr,
  	&sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
  	&sensor_dev_attr_temp2_crit_hyst.dev_attr.attr,
  
  	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,

  	&sensor_dev_attr_temp2_fault.dev_attr.attr,

  	&sensor_dev_attr_temp2_min_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
  	&dev_attr_alarms.attr,

  	&dev_attr_update_interval.attr,

  	NULL
  };
  
  static const struct attribute_group lm90_group = {
  	.attrs = lm90_attributes,
  };

  /*
   * Additional attributes for devices with emergency sensors
   */
  static SENSOR_DEVICE_ATTR(temp1_emergency, S_IWUSR | S_IRUGO, show_temp8,
  	set_temp8, 4);
  static SENSOR_DEVICE_ATTR(temp2_emergency, S_IWUSR | S_IRUGO, show_temp8,
  	set_temp8, 5);
  static SENSOR_DEVICE_ATTR(temp1_emergency_hyst, S_IRUGO, show_temphyst,
  			  NULL, 4);
  static SENSOR_DEVICE_ATTR(temp2_emergency_hyst, S_IRUGO, show_temphyst,
  			  NULL, 5);
  
  static struct attribute *lm90_emergency_attributes[] = {
  	&sensor_dev_attr_temp1_emergency.dev_attr.attr,
  	&sensor_dev_attr_temp2_emergency.dev_attr.attr,
  	&sensor_dev_attr_temp1_emergency_hyst.dev_attr.attr,
  	&sensor_dev_attr_temp2_emergency_hyst.dev_attr.attr,
  	NULL
  };
  
  static const struct attribute_group lm90_emergency_group = {
  	.attrs = lm90_emergency_attributes,
  };

  static SENSOR_DEVICE_ATTR(temp1_emergency_alarm, S_IRUGO, show_alarm, NULL, 15);
  static SENSOR_DEVICE_ATTR(temp2_emergency_alarm, S_IRUGO, show_alarm, NULL, 13);
  
  static struct attribute *lm90_emergency_alarm_attributes[] = {
  	&sensor_dev_attr_temp1_emergency_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp2_emergency_alarm.dev_attr.attr,
  	NULL
  };
  
  static const struct attribute_group lm90_emergency_alarm_group = {
  	.attrs = lm90_emergency_alarm_attributes,
  };
  
  /*
   * Additional attributes for devices with 3 temperature sensors
   */
  static SENSOR_DEVICE_ATTR_2(temp3_input, S_IRUGO, show_temp11, NULL, 0, 5);
  static SENSOR_DEVICE_ATTR_2(temp3_min, S_IWUSR | S_IRUGO, show_temp11,
  	set_temp11, 3, 6);
  static SENSOR_DEVICE_ATTR_2(temp3_max, S_IWUSR | S_IRUGO, show_temp11,
  	set_temp11, 4, 7);
  static SENSOR_DEVICE_ATTR(temp3_crit, S_IWUSR | S_IRUGO, show_temp8,
  	set_temp8, 6);
  static SENSOR_DEVICE_ATTR(temp3_crit_hyst, S_IRUGO, show_temphyst, NULL, 6);
  static SENSOR_DEVICE_ATTR(temp3_emergency, S_IWUSR | S_IRUGO, show_temp8,
  	set_temp8, 7);
  static SENSOR_DEVICE_ATTR(temp3_emergency_hyst, S_IRUGO, show_temphyst,
  			  NULL, 7);
  
  static SENSOR_DEVICE_ATTR(temp3_crit_alarm, S_IRUGO, show_alarm, NULL, 9);
  static SENSOR_DEVICE_ATTR(temp3_fault, S_IRUGO, show_alarm, NULL, 10);
  static SENSOR_DEVICE_ATTR(temp3_min_alarm, S_IRUGO, show_alarm, NULL, 11);
  static SENSOR_DEVICE_ATTR(temp3_max_alarm, S_IRUGO, show_alarm, NULL, 12);
  static SENSOR_DEVICE_ATTR(temp3_emergency_alarm, S_IRUGO, show_alarm, NULL, 14);
  
  static struct attribute *lm90_temp3_attributes[] = {
  	&sensor_dev_attr_temp3_input.dev_attr.attr,
  	&sensor_dev_attr_temp3_min.dev_attr.attr,
  	&sensor_dev_attr_temp3_max.dev_attr.attr,
  	&sensor_dev_attr_temp3_crit.dev_attr.attr,
  	&sensor_dev_attr_temp3_crit_hyst.dev_attr.attr,
  	&sensor_dev_attr_temp3_emergency.dev_attr.attr,
  	&sensor_dev_attr_temp3_emergency_hyst.dev_attr.attr,
  
  	&sensor_dev_attr_temp3_fault.dev_attr.attr,
  	&sensor_dev_attr_temp3_min_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp3_max_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp3_crit_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp3_emergency_alarm.dev_attr.attr,
  	NULL
  };
  
  static const struct attribute_group lm90_temp3_group = {
  	.attrs = lm90_temp3_attributes,
  };

  /* pec used for ADM1032 only */
  static ssize_t show_pec(struct device *dev, struct device_attribute *dummy,
  			char *buf)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	return sprintf(buf, "%d
  ", !!(client->flags & I2C_CLIENT_PEC));
  }
  
  static ssize_t set_pec(struct device *dev, struct device_attribute *dummy,
  		       const char *buf, size_t count)
  {
  	struct i2c_client *client = to_i2c_client(dev);

  	long val;
  	int err;

  	err = kstrtol(buf, 10, &val);

  	if (err < 0)
  		return err;

  
  	switch (val) {
  	case 0:
  		client->flags &= ~I2C_CLIENT_PEC;
  		break;
  	case 1:
  		client->flags |= I2C_CLIENT_PEC;
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	return count;
  }
  
  static DEVICE_ATTR(pec, S_IWUSR | S_IRUGO, show_pec, set_pec);

  /*
   * Real code
   */

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

  static int lm90_detect(struct i2c_client *client,

  		       struct i2c_board_info *info)

  {

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

  	const char *name = NULL;

  	int man_id, chip_id, config1, config2, convrate;

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

  	/* detection and identification */

  	man_id = i2c_smbus_read_byte_data(client, LM90_REG_R_MAN_ID);
  	chip_id = i2c_smbus_read_byte_data(client, LM90_REG_R_CHIP_ID);
  	config1 = i2c_smbus_read_byte_data(client, LM90_REG_R_CONFIG1);
  	convrate = i2c_smbus_read_byte_data(client, LM90_REG_R_CONVRATE);
  	if (man_id < 0 || chip_id < 0 || config1 < 0 || convrate < 0)

  		return -ENODEV;

  	if (man_id == 0x01 || man_id == 0x5C || man_id == 0x41) {

  		config2 = i2c_smbus_read_byte_data(client, LM90_REG_R_CONFIG2);
  		if (config2 < 0)

  			return -ENODEV;

  	} else

  		config2 = 0;		/* Make compiler happy */

  	if ((address == 0x4C || address == 0x4D)
  	 && man_id == 0x01) { /* National Semiconductor */

  		if ((config1 & 0x2A) == 0x00
  		 && (config2 & 0xF8) == 0x00
  		 && convrate <= 0x09) {

  			if (address == 0x4C
  			 && (chip_id & 0xF0) == 0x20) { /* LM90 */
  				name = "lm90";

  			} else

  			if ((chip_id & 0xF0) == 0x30) { /* LM89/LM99 */
  				name = "lm99";
  				dev_info(&adapter->dev,
  					 "Assuming LM99 chip at 0x%02x
  ",
  					 address);
  				dev_info(&adapter->dev,
  					 "If it is an LM89, instantiate it "
  					 "with the new_device sysfs "
  					 "interface
  ");

  			} else

  			if (address == 0x4C
  			 && (chip_id & 0xF0) == 0x10) { /* LM86 */
  				name = "lm86";

  			}
  		}

  	} else
  	if ((address == 0x4C || address == 0x4D)
  	 && man_id == 0x41) { /* Analog Devices */
  		if ((chip_id & 0xF0) == 0x40 /* ADM1032 */

  		 && (config1 & 0x3F) == 0x00
  		 && convrate <= 0x0A) {

  			name = "adm1032";
  			/* The ADM1032 supports PEC, but only if combined
  			   transactions are not used. */
  			if (i2c_check_functionality(adapter,
  						    I2C_FUNC_SMBUS_BYTE))
  				info->flags |= I2C_CLIENT_PEC;
  		} else
  		if (chip_id == 0x51 /* ADT7461 */

  		 && (config1 & 0x1B) == 0x00
  		 && convrate <= 0x0A) {

  			name = "adt7461";

  		} else
  		if (chip_id == 0x57 /* ADT7461A, NCT1008 */

  		 && (config1 & 0x1B) == 0x00
  		 && convrate <= 0x0A) {

  			name = "adt7461a";

  		}
  	} else
  	if (man_id == 0x4D) { /* Maxim */

  		int emerg, emerg2, status2;

  
  		/*
  		 * We read MAX6659_REG_R_REMOTE_EMERG twice, and re-read
  		 * LM90_REG_R_MAN_ID in between. If MAX6659_REG_R_REMOTE_EMERG
  		 * exists, both readings will reflect the same value. Otherwise,
  		 * the readings will be different.
  		 */

  		emerg = i2c_smbus_read_byte_data(client,
  						 MAX6659_REG_R_REMOTE_EMERG);
  		man_id = i2c_smbus_read_byte_data(client,

  						  LM90_REG_R_MAN_ID);

  		emerg2 = i2c_smbus_read_byte_data(client,

  						  MAX6659_REG_R_REMOTE_EMERG);

  		status2 = i2c_smbus_read_byte_data(client,
  						   MAX6696_REG_R_STATUS2);
  		if (emerg < 0 || man_id < 0 || emerg2 < 0 || status2 < 0)

  			return -ENODEV;

  		/*
  		 * The MAX6657, MAX6658 and MAX6659 do NOT have a chip_id
  		 * register. Reading from that address will return the last
  		 * read value, which in our case is those of the man_id
  		 * register. Likewise, the config1 register seems to lack a
  		 * low nibble, so the value will be those of the previous
  		 * read, so in our case those of the man_id register.

  		 * MAX6659 has a third set of upper temperature limit registers.
  		 * Those registers also return values on MAX6657 and MAX6658,
  		 * thus the only way to detect MAX6659 is by its address.
  		 * For this reason it will be mis-detected as MAX6657 if its
  		 * address is 0x4C.

  		 */
  		if (chip_id == man_id

  		 && (address == 0x4C || address == 0x4D || address == 0x4E)

  		 && (config1 & 0x1F) == (man_id & 0x0F)
  		 && convrate <= 0x09) {

  			if (address == 0x4C)
  				name = "max6657";
  			else
  				name = "max6659";

  		} else
  		/*

  		 * Even though MAX6695 and MAX6696 do not have a chip ID
  		 * register, reading it returns 0x01. Bit 4 of the config1
  		 * register is unused and should return zero when read. Bit 0 of
  		 * the status2 register is unused and should return zero when
  		 * read.
  		 *
  		 * MAX6695 and MAX6696 have an additional set of temperature
  		 * limit registers. We can detect those chips by checking if
  		 * one of those registers exists.
  		 */
  		if (chip_id == 0x01

  		 && (config1 & 0x10) == 0x00
  		 && (status2 & 0x01) == 0x00
  		 && emerg == emerg2
  		 && convrate <= 0x07) {

  			name = "max6696";
  		} else
  		/*

  		 * The chip_id register of the MAX6680 and MAX6681 holds the
  		 * revision of the chip. The lowest bit of the config1 register
  		 * is unused and should return zero when read, so should the
  		 * second to last bit of config1 (software reset).
  		 */
  		if (chip_id == 0x01

  		 && (config1 & 0x03) == 0x00
  		 && convrate <= 0x07) {

  			name = "max6680";
  		} else
  		/*
  		 * The chip_id register of the MAX6646/6647/6649 holds the
  		 * revision of the chip. The lowest 6 bits of the config1
  		 * register are unused and should return zero when read.
  		 */
  		if (chip_id == 0x59

  		 && (config1 & 0x3f) == 0x00
  		 && convrate <= 0x07) {

  			name = "max6646";

  		}

  	} else
  	if (address == 0x4C
  	 && man_id == 0x5C) { /* Winbond/Nuvoton */

  		if ((config1 & 0x2A) == 0x00
  		 && (config2 & 0xF8) == 0x00) {

  			if (chip_id == 0x01 /* W83L771W/G */

  			 && convrate <= 0x09) {

  				name = "w83l771";
  			} else
  			if ((chip_id & 0xFE) == 0x10 /* W83L771AWG/ASG */

  			 && convrate <= 0x08) {

  				name = "w83l771";
  			}

  		}

  	} else

  	if (address >= 0x48 && address <= 0x4F
  	 && man_id == 0xA1) { /*  NXP Semiconductor/Philips */

  		if (chip_id == 0x00

  		 && (config1 & 0x2A) == 0x00
  		 && (config2 & 0xFE) == 0x00
  		 && convrate <= 0x09) {

  			name = "sa56004";
  		}

  	}

  	if (!name) { /* identification failed */
  		dev_dbg(&adapter->dev,
  			"Unsupported chip at 0x%02x (man_id=0x%02X, "
  			"chip_id=0x%02X)
  ", address, man_id, chip_id);
  		return -ENODEV;

  	}

  	strlcpy(info->type, name, I2C_NAME_SIZE);
  
  	return 0;
  }

  static void lm90_remove_files(struct i2c_client *client, struct lm90_data *data)
  {

  	struct device *dev = &client->dev;

  	if (data->flags & LM90_HAVE_TEMP3)

  		sysfs_remove_group(&dev->kobj, &lm90_temp3_group);

  	if (data->flags & LM90_HAVE_EMERGENCY_ALARM)

  		sysfs_remove_group(&dev->kobj, &lm90_emergency_alarm_group);

  	if (data->flags & LM90_HAVE_EMERGENCY)

  		sysfs_remove_group(&dev->kobj, &lm90_emergency_group);

  	if (data->flags & LM90_HAVE_OFFSET)

  		device_remove_file(dev, &sensor_dev_attr_temp2_offset.dev_attr);
  	device_remove_file(dev, &dev_attr_pec);
  	sysfs_remove_group(&dev->kobj, &lm90_group);

  }

  static void lm90_init_client(struct i2c_client *client)
  {

  	u8 config, convrate;

  	struct lm90_data *data = i2c_get_clientdata(client);

  	if (lm90_read_reg(client, LM90_REG_R_CONVRATE, &convrate) < 0) {
  		dev_warn(&client->dev, "Failed to read convrate register!
  ");
  		convrate = LM90_DEF_CONVRATE_RVAL;
  	}
  	data->convrate_orig = convrate;

  	/*
  	 * Start the conversions.
  	 */

  	lm90_set_convrate(client, data, 500);	/* 500ms; 2Hz conversion rate */

  	if (lm90_read_reg(client, LM90_REG_R_CONFIG1, &config) < 0) {
  		dev_warn(&client->dev, "Initialization failed!
  ");
  		return;
  	}
  	data->config_orig = config;
  
  	/* Check Temperature Range Select */
  	if (data->kind == adt7461) {
  		if (config & 0x04)
  			data->flags |= LM90_FLAG_ADT7461_EXT;
  	}
  
  	/*
  	 * Put MAX6680/MAX8881 into extended resolution (bit 0x10,
  	 * 0.125 degree resolution) and range (0x08, extend range
  	 * to -64 degree) mode for the remote temperature sensor.
  	 */
  	if (data->kind == max6680)
  		config |= 0x18;
  
  	/*
  	 * Select external channel 0 for max6695/96
  	 */
  	if (data->kind == max6696)
  		config &= ~0x08;
  
  	config &= 0xBF;	/* run */
  	if (config != data->config_orig) /* Only write if changed */
  		i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1, config);
  }

  static int lm90_probe(struct i2c_client *client,

  		      const struct i2c_device_id *id)
  {

  	struct device *dev = &client->dev;
  	struct i2c_adapter *adapter = to_i2c_adapter(dev->parent);

  	struct lm90_data *data;
  	int err;

  	data = kzalloc(sizeof(struct lm90_data), GFP_KERNEL);
  	if (!data) {
  		err = -ENOMEM;
  		goto exit;
  	}

  	i2c_set_clientdata(client, data);

  	mutex_init(&data->update_lock);

  	/* Set the device type */
  	data->kind = id->driver_data;
  	if (data->kind == adm1032) {
  		if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))

  			client->flags &= ~I2C_CLIENT_PEC;

  	}

  	/* Different devices have different alarm bits triggering the
  	 * ALERT# output */

  	data->alert_alarms = lm90_params[data->kind].alert_alarms;

  	/* Set chip capabilities */

  	data->flags = lm90_params[data->kind].flags;

  	data->reg_local_ext = lm90_params[data->kind].reg_local_ext;

  	/* Set maximum conversion rate */
  	data->max_convrate = lm90_params[data->kind].max_convrate;

  	/* Initialize the LM90 chip */

  	lm90_init_client(client);

  
  	/* Register sysfs hooks */

  	err = sysfs_create_group(&dev->kobj, &lm90_group);

  	if (err)

  		goto exit_free;

  	if (client->flags & I2C_CLIENT_PEC) {
  		err = device_create_file(dev, &dev_attr_pec);

  		if (err)

  			goto exit_remove_files;
  	}

  	if (data->flags & LM90_HAVE_OFFSET) {

  		err = device_create_file(dev,

  					&sensor_dev_attr_temp2_offset.dev_attr);
  		if (err)

  			goto exit_remove_files;
  	}

  	if (data->flags & LM90_HAVE_EMERGENCY) {

  		err = sysfs_create_group(&dev->kobj, &lm90_emergency_group);

  		if (err)
  			goto exit_remove_files;
  	}

  	if (data->flags & LM90_HAVE_EMERGENCY_ALARM) {

  		err = sysfs_create_group(&dev->kobj,

  					 &lm90_emergency_alarm_group);
  		if (err)
  			goto exit_remove_files;
  	}
  	if (data->flags & LM90_HAVE_TEMP3) {

  		err = sysfs_create_group(&dev->kobj, &lm90_temp3_group);

  		if (err)
  			goto exit_remove_files;
  	}

  	data->hwmon_dev = hwmon_device_register(dev);

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

  		goto exit_remove_files;

  	}

  	return 0;

  exit_remove_files:

  	lm90_remove_files(client, data);

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

  static int lm90_remove(struct i2c_client *client)

  {

  	struct lm90_data *data = i2c_get_clientdata(client);

  	hwmon_device_unregister(data->hwmon_dev);

  	lm90_remove_files(client, data);

  	/* Restore initial configuration */

  	i2c_smbus_write_byte_data(client, LM90_REG_W_CONVRATE,
  				  data->convrate_orig);

  	i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
  				  data->config_orig);

  	kfree(data);

  	return 0;
  }

  static void lm90_alert(struct i2c_client *client, unsigned int flag)
  {
  	struct lm90_data *data = i2c_get_clientdata(client);

  	u8 config, alarms, alarms2 = 0;

  
  	lm90_read_reg(client, LM90_REG_R_STATUS, &alarms);

  
  	if (data->kind == max6696)
  		lm90_read_reg(client, MAX6696_REG_R_STATUS2, &alarms2);
  
  	if ((alarms & 0x7f) == 0 && (alarms2 & 0xfe) == 0) {

  		dev_info(&client->dev, "Everything OK
  ");
  	} else {
  		if (alarms & 0x61)
  			dev_warn(&client->dev,
  				 "temp%d out of range, please check!
  ", 1);
  		if (alarms & 0x1a)
  			dev_warn(&client->dev,
  				 "temp%d out of range, please check!
  ", 2);
  		if (alarms & 0x04)
  			dev_warn(&client->dev,
  				 "temp%d diode open, please check!
  ", 2);

  		if (alarms2 & 0x18)
  			dev_warn(&client->dev,
  				 "temp%d out of range, please check!
  ", 3);

  		/* Disable ALERT# output, because these chips don't implement
  		  SMBus alert correctly; they should only hold the alert line
  		  low briefly. */

  		if ((data->flags & LM90_HAVE_BROKEN_ALERT)

  		 && (alarms & data->alert_alarms)) {
  			dev_dbg(&client->dev, "Disabling ALERT#
  ");
  			lm90_read_reg(client, LM90_REG_R_CONFIG1, &config);
  			i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
  						  config | 0x80);
  		}
  	}
  }

  static struct i2c_driver lm90_driver = {
  	.class		= I2C_CLASS_HWMON,
  	.driver = {
  		.name	= "lm90",
  	},
  	.probe		= lm90_probe,
  	.remove		= lm90_remove,
  	.alert		= lm90_alert,
  	.id_table	= lm90_id,
  	.detect		= lm90_detect,
  	.address_list	= normal_i2c,
  };

  
  static int __init sensors_lm90_init(void)
  {
  	return i2c_add_driver(&lm90_driver);
  }
  
  static void __exit sensors_lm90_exit(void)
  {
  	i2c_del_driver(&lm90_driver);
  }
  
  MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
  MODULE_DESCRIPTION("LM90/ADM1032 driver");
  MODULE_LICENSE("GPL");
  
  module_init(sensors_lm90_init);
  module_exit(sensors_lm90_exit);