drivers/hwmon/max1668.c - kernel/mindspeed - Git at Google

 /*
     Copyright (c) 2011 David George <david.george@ska.ac.za>

     based on adm1021.c
     some credit to Christoph Scheurer, but largely a rewrite

     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.h>
 #include <linux/hwmon-sysfs.h>
 #include <linux/err.h>
 #include <linux/mutex.h>

 /* Addresses to scan */
 static unsigned short max1668_addr_list[] = {
 	0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, 0x4c, 0x4d, 0x4e, I2C_CLIENT_END };

 /* max1668 registers */

 #define MAX1668_REG_TEMP(nr)	(nr)
 #define MAX1668_REG_STAT1	0x05
 #define MAX1668_REG_STAT2	0x06
 #define MAX1668_REG_MAN_ID	0xfe
 #define MAX1668_REG_DEV_ID	0xff

 /* limits */

 /* write high limits */
 #define MAX1668_REG_LIMH_WR(nr)	(0x13 + 2 * (nr))
 /* write low limits */
 #define MAX1668_REG_LIML_WR(nr)	(0x14 + 2 * (nr))
 /* read high limits */
 #define MAX1668_REG_LIMH_RD(nr)	(0x08 + 2 * (nr))
 /* read low limits */
 #define MAX1668_REG_LIML_RD(nr)	(0x09 + 2 * (nr))

 /* manufacturer and device ID Constants */
 #define MAN_ID_MAXIM		0x4d
 #define DEV_ID_MAX1668		0x3
 #define DEV_ID_MAX1805		0x5
 #define DEV_ID_MAX1989		0xb

 /* read only mode module parameter */
 static int read_only;
 module_param(read_only, bool, 0);
 MODULE_PARM_DESC(read_only, "Don't set any values, read only mode");

 enum chips { max1668, max1805, max1989 };

 struct max1668_data {
 	struct device *hwmon_dev;
 	enum chips type;

 	struct mutex update_lock;
 	char valid;		/* !=0 if following fields are valid */
 	unsigned long last_updated;	/* In jiffies */

 	/* 1x local and 4x remote */
 	s8 temp_max[5];
 	s8 temp_min[5];
 	s8 temp[5];
 	u16 alarms;
 };

 static struct max1668_data *max1668_update_device(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct max1668_data *data = i2c_get_clientdata(client);
 	struct max1668_data *ret = data;
 	s32 val;
 	int i;

 	mutex_lock(&data->update_lock);

 	if (data->valid && !time_after(jiffies,
 			data->last_updated + HZ + HZ / 2))
 		goto abort;

 	for (i = 0; i < 5; i++) {
 		val = i2c_smbus_read_byte_data(client, MAX1668_REG_TEMP(i));
 		if (unlikely(val < 0)) {
 			ret = ERR_PTR(val);
 			goto abort;
 		}
 		data->temp[i] = (s8) val;

 		val = i2c_smbus_read_byte_data(client, MAX1668_REG_LIMH_RD(i));
 		if (unlikely(val < 0)) {
 			ret = ERR_PTR(val);
 			goto abort;
 		}
 		data->temp_max[i] = (s8) val;

 		val = i2c_smbus_read_byte_data(client, MAX1668_REG_LIML_RD(i));
 		if (unlikely(val < 0)) {
 			ret = ERR_PTR(val);
 			goto abort;
 		}
 		data->temp_min[i] = (s8) val;
 	}

 	val = i2c_smbus_read_byte_data(client, MAX1668_REG_STAT1);
 	if (unlikely(val < 0)) {
 		ret = ERR_PTR(val);
 		goto abort;
 	}
 	data->alarms = val << 8;

 	val = i2c_smbus_read_byte_data(client, MAX1668_REG_STAT2);
 	if (unlikely(val < 0)) {
 		ret = ERR_PTR(val);
 		goto abort;
 	}
 	data->alarms |= val;

 	data->last_updated = jiffies;
 	data->valid = 1;
 abort:
 	mutex_unlock(&data->update_lock);

 	return ret;
 }

 static ssize_t show_temp(struct device *dev,
 			 struct device_attribute *devattr, char *buf)
 {
 	int index = to_sensor_dev_attr(devattr)->index;
 	struct max1668_data *data = max1668_update_device(dev);

 	if (IS_ERR(data))
 		return PTR_ERR(data);

 	return sprintf(buf, "%d\n", data->temp[index] * 1000);
 }

 static ssize_t show_temp_max(struct device *dev,
 			     struct device_attribute *devattr, char *buf)
 {
 	int index = to_sensor_dev_attr(devattr)->index;
 	struct max1668_data *data = max1668_update_device(dev);

 	if (IS_ERR(data))
 		return PTR_ERR(data);

 	return sprintf(buf, "%d\n", data->temp_max[index] * 1000);
 }

 static ssize_t show_temp_min(struct device *dev,
 			     struct device_attribute *devattr, char *buf)
 {
 	int index = to_sensor_dev_attr(devattr)->index;
 	struct max1668_data *data = max1668_update_device(dev);

 	if (IS_ERR(data))
 		return PTR_ERR(data);

 	return sprintf(buf, "%d\n", data->temp_min[index] * 1000);
 }

 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
 			  char *buf)
 {
 	int index = to_sensor_dev_attr(attr)->index;
 	struct max1668_data *data = max1668_update_device(dev);

 	if (IS_ERR(data))
 		return PTR_ERR(data);

 	return sprintf(buf, "%u\n", (data->alarms >> index) & 0x1);
 }

 static ssize_t show_fault(struct device *dev,
 			  struct device_attribute *devattr, char *buf)
 {
 	int index = to_sensor_dev_attr(devattr)->index;
 	struct max1668_data *data = max1668_update_device(dev);

 	if (IS_ERR(data))
 		return PTR_ERR(data);

 	return sprintf(buf, "%u\n",
 		       (data->alarms & (1 << 12)) && data->temp[index] == 127);
 }

 static ssize_t set_temp_max(struct device *dev,
 			    struct device_attribute *devattr,
 			    const char *buf, size_t count)
 {
 	int index = to_sensor_dev_attr(devattr)->index;
 	struct i2c_client *client = to_i2c_client(dev);
 	struct max1668_data *data = i2c_get_clientdata(client);
 	long temp;
 	int ret;

 	ret = kstrtol(buf, 10, &temp);
 	if (ret < 0)
 		return ret;

 	mutex_lock(&data->update_lock);
 	data->temp_max[index] = SENSORS_LIMIT(temp/1000, -128, 127);
 	if (i2c_smbus_write_byte_data(client,
 					MAX1668_REG_LIMH_WR(index),
 					data->temp_max[index]))
 		count = -EIO;
 	mutex_unlock(&data->update_lock);

 	return count;
 }

 static ssize_t set_temp_min(struct device *dev,
 			    struct device_attribute *devattr,
 			    const char *buf, size_t count)
 {
 	int index = to_sensor_dev_attr(devattr)->index;
 	struct i2c_client *client = to_i2c_client(dev);
 	struct max1668_data *data = i2c_get_clientdata(client);
 	long temp;
 	int ret;

 	ret = kstrtol(buf, 10, &temp);
 	if (ret < 0)
 		return ret;

 	mutex_lock(&data->update_lock);
 	data->temp_min[index] = SENSORS_LIMIT(temp/1000, -128, 127);
 	if (i2c_smbus_write_byte_data(client,
 					MAX1668_REG_LIML_WR(index),
 					data->temp_max[index]))
 		count = -EIO;
 	mutex_unlock(&data->update_lock);

 	return count;
 }

 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp_max,
 				set_temp_max, 0);
 static SENSOR_DEVICE_ATTR(temp1_min, S_IRUGO, show_temp_min,
 				set_temp_min, 0);
 static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp, NULL, 1);
 static SENSOR_DEVICE_ATTR(temp2_max, S_IRUGO, show_temp_max,
 				set_temp_max, 1);
 static SENSOR_DEVICE_ATTR(temp2_min, S_IRUGO, show_temp_min,
 				set_temp_min, 1);
 static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_temp, NULL, 2);
 static SENSOR_DEVICE_ATTR(temp3_max, S_IRUGO, show_temp_max,
 				set_temp_max, 2);
 static SENSOR_DEVICE_ATTR(temp3_min, S_IRUGO, show_temp_min,
 				set_temp_min, 2);
 static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, show_temp, NULL, 3);
 static SENSOR_DEVICE_ATTR(temp4_max, S_IRUGO, show_temp_max,
 				set_temp_max, 3);
 static SENSOR_DEVICE_ATTR(temp4_min, S_IRUGO, show_temp_min,
 				set_temp_min, 3);
 static SENSOR_DEVICE_ATTR(temp5_input, S_IRUGO, show_temp, NULL, 4);
 static SENSOR_DEVICE_ATTR(temp5_max, S_IRUGO, show_temp_max,
 				set_temp_max, 4);
 static SENSOR_DEVICE_ATTR(temp5_min, S_IRUGO, show_temp_min,
 				set_temp_min, 4);

 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 14);
 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 13);
 static SENSOR_DEVICE_ATTR(temp2_min_alarm, S_IRUGO, show_alarm, NULL, 7);
 static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_alarm, NULL, 6);
 static SENSOR_DEVICE_ATTR(temp3_min_alarm, S_IRUGO, show_alarm, NULL, 5);
 static SENSOR_DEVICE_ATTR(temp3_max_alarm, S_IRUGO, show_alarm, NULL, 4);
 static SENSOR_DEVICE_ATTR(temp4_min_alarm, S_IRUGO, show_alarm, NULL, 3);
 static SENSOR_DEVICE_ATTR(temp4_max_alarm, S_IRUGO, show_alarm, NULL, 2);
 static SENSOR_DEVICE_ATTR(temp5_min_alarm, S_IRUGO, show_alarm, NULL, 1);
 static SENSOR_DEVICE_ATTR(temp5_max_alarm, S_IRUGO, show_alarm, NULL, 0);

 static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_fault, NULL, 1);
 static SENSOR_DEVICE_ATTR(temp3_fault, S_IRUGO, show_fault, NULL, 2);
 static SENSOR_DEVICE_ATTR(temp4_fault, S_IRUGO, show_fault, NULL, 3);
 static SENSOR_DEVICE_ATTR(temp5_fault, S_IRUGO, show_fault, NULL, 4);

 /* Attributes common to MAX1668, MAX1989 and MAX1805 */
 static struct attribute *max1668_attribute_common[] = {
 	&sensor_dev_attr_temp1_max.dev_attr.attr,
 	&sensor_dev_attr_temp1_min.dev_attr.attr,
 	&sensor_dev_attr_temp1_input.dev_attr.attr,
 	&sensor_dev_attr_temp2_max.dev_attr.attr,
 	&sensor_dev_attr_temp2_min.dev_attr.attr,
 	&sensor_dev_attr_temp2_input.dev_attr.attr,
 	&sensor_dev_attr_temp3_max.dev_attr.attr,
 	&sensor_dev_attr_temp3_min.dev_attr.attr,
 	&sensor_dev_attr_temp3_input.dev_attr.attr,

 	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 	&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
 	&sensor_dev_attr_temp2_min_alarm.dev_attr.attr,
 	&sensor_dev_attr_temp3_max_alarm.dev_attr.attr,
 	&sensor_dev_attr_temp3_min_alarm.dev_attr.attr,

 	&sensor_dev_attr_temp2_fault.dev_attr.attr,
 	&sensor_dev_attr_temp3_fault.dev_attr.attr,
 	NULL
 };

 /* Attributes not present on MAX1805 */
 static struct attribute *max1668_attribute_unique[] = {
 	&sensor_dev_attr_temp4_max.dev_attr.attr,
 	&sensor_dev_attr_temp4_min.dev_attr.attr,
 	&sensor_dev_attr_temp4_input.dev_attr.attr,
 	&sensor_dev_attr_temp5_max.dev_attr.attr,
 	&sensor_dev_attr_temp5_min.dev_attr.attr,
 	&sensor_dev_attr_temp5_input.dev_attr.attr,

 	&sensor_dev_attr_temp4_max_alarm.dev_attr.attr,
 	&sensor_dev_attr_temp4_min_alarm.dev_attr.attr,
 	&sensor_dev_attr_temp5_max_alarm.dev_attr.attr,
 	&sensor_dev_attr_temp5_min_alarm.dev_attr.attr,

 	&sensor_dev_attr_temp4_fault.dev_attr.attr,
 	&sensor_dev_attr_temp5_fault.dev_attr.attr,
 	NULL
 };

 static mode_t max1668_attribute_mode(struct kobject *kobj,
 				     struct attribute *attr, int index)
 {
 	int ret = S_IRUGO;
 	if (read_only)
 		return ret;
 	if (attr == &sensor_dev_attr_temp1_max.dev_attr.attr ||
 	    attr == &sensor_dev_attr_temp2_max.dev_attr.attr ||
 	    attr == &sensor_dev_attr_temp3_max.dev_attr.attr ||
 	    attr == &sensor_dev_attr_temp4_max.dev_attr.attr ||
 	    attr == &sensor_dev_attr_temp5_max.dev_attr.attr ||
 	    attr == &sensor_dev_attr_temp1_min.dev_attr.attr ||
 	    attr == &sensor_dev_attr_temp2_min.dev_attr.attr ||
 	    attr == &sensor_dev_attr_temp3_min.dev_attr.attr ||
 	    attr == &sensor_dev_attr_temp4_min.dev_attr.attr ||
 	    attr == &sensor_dev_attr_temp5_min.dev_attr.attr)
 		ret |= S_IWUSR;
 	return ret;
 }

 static const struct attribute_group max1668_group_common = {
 	.attrs = max1668_attribute_common,
 	.is_visible = max1668_attribute_mode
 };

 static const struct attribute_group max1668_group_unique = {
 	.attrs = max1668_attribute_unique,
 	.is_visible = max1668_attribute_mode
 };

 /* Return 0 if detection is successful, -ENODEV otherwise */
 static int max1668_detect(struct i2c_client *client,
 			  struct i2c_board_info *info)
 {
 	struct i2c_adapter *adapter = client->adapter;
 	const char *type_name;
 	int man_id, dev_id;

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

 	/* Check for unsupported part */
 	man_id = i2c_smbus_read_byte_data(client, MAX1668_REG_MAN_ID);
 	if (man_id != MAN_ID_MAXIM)
 		return -ENODEV;

 	dev_id = i2c_smbus_read_byte_data(client, MAX1668_REG_DEV_ID);
 	if (dev_id < 0)
 		return -ENODEV;

 	type_name = NULL;
 	if (dev_id == DEV_ID_MAX1668)
 		type_name = "max1668";
 	else if (dev_id == DEV_ID_MAX1805)
 		type_name = "max1805";
 	else if (dev_id == DEV_ID_MAX1989)
 		type_name = "max1989";

 	if (!type_name)
 		return -ENODEV;

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

 	return 0;
 }

 static int max1668_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
 	struct i2c_adapter *adapter = client->adapter;
 	struct max1668_data *data;
 	int err;

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

 	data = kzalloc(sizeof(struct max1668_data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;

 	i2c_set_clientdata(client, data);
 	data->type = id->driver_data;
 	mutex_init(&data->update_lock);

 	/* Register sysfs hooks */
 	err = sysfs_create_group(&client->dev.kobj, &max1668_group_common);
 	if (err)
 		goto error_free;

 	if (data->type == max1668 || data->type == max1989) {
 		err = sysfs_create_group(&client->dev.kobj,
 					 &max1668_group_unique);
 		if (err)
 			goto error_sysrem0;
 	}

 	data->hwmon_dev = hwmon_device_register(&client->dev);
 	if (IS_ERR(data->hwmon_dev)) {
 		err = PTR_ERR(data->hwmon_dev);
 		goto error_sysrem1;
 	}

 	return 0;

 error_sysrem1:
 	if (data->type == max1668 || data->type == max1989)
 		sysfs_remove_group(&client->dev.kobj, &max1668_group_unique);
 error_sysrem0:
 	sysfs_remove_group(&client->dev.kobj, &max1668_group_common);
 error_free:
 	kfree(data);
 	return err;
 }

 static int max1668_remove(struct i2c_client *client)
 {
 	struct max1668_data *data = i2c_get_clientdata(client);

 	hwmon_device_unregister(data->hwmon_dev);
 	if (data->type == max1668 || data->type == max1989)
 		sysfs_remove_group(&client->dev.kobj, &max1668_group_unique);

 	sysfs_remove_group(&client->dev.kobj, &max1668_group_common);

 	kfree(data);
 	return 0;
 }

 static const struct i2c_device_id max1668_id[] = {
 	{ "max1668", max1668 },
 	{ "max1805", max1805 },
 	{ "max1989", max1989 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, max1668_id);

 /* This is the driver that will be inserted */
 static struct i2c_driver max1668_driver = {
 	.class = I2C_CLASS_HWMON,
 	.driver = {
 		  .name	= "max1668",
 		  },
 	.probe = max1668_probe,
 	.remove	= max1668_remove,
 	.id_table = max1668_id,
 	.detect	= max1668_detect,
 	.address_list = max1668_addr_list,
 };

 static int __init sensors_max1668_init(void)
 {
 	return i2c_add_driver(&max1668_driver);
 }

 static void __exit sensors_max1668_exit(void)
 {
 	i2c_del_driver(&max1668_driver);
 }

 MODULE_AUTHOR("David George <david.george@ska.ac.za>");
 MODULE_DESCRIPTION("MAX1668 remote temperature sensor driver");
 MODULE_LICENSE("GPL");

 module_init(sensors_max1668_init)
 module_exit(sensors_max1668_exit)
	/*
	Copyright (c) 2011 David George <david.george@ska.ac.za>

	based on adm1021.c
	some credit to Christoph Scheurer, but largely a rewrite

	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.h>
	#include <linux/hwmon-sysfs.h>
	#include <linux/err.h>
	#include <linux/mutex.h>

	/* Addresses to scan */
	static unsigned short max1668_addr_list[] = {
	0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, 0x4c, 0x4d, 0x4e, I2C_CLIENT_END };

	/* max1668 registers */

	#define MAX1668_REG_TEMP(nr) (nr)
	#define MAX1668_REG_STAT1 0x05
	#define MAX1668_REG_STAT2 0x06
	#define MAX1668_REG_MAN_ID 0xfe
	#define MAX1668_REG_DEV_ID 0xff

	/* limits */

	/* write high limits */
	#define MAX1668_REG_LIMH_WR(nr) (0x13 + 2 * (nr))
	/* write low limits */
	#define MAX1668_REG_LIML_WR(nr) (0x14 + 2 * (nr))
	/* read high limits */
	#define MAX1668_REG_LIMH_RD(nr) (0x08 + 2 * (nr))
	/* read low limits */
	#define MAX1668_REG_LIML_RD(nr) (0x09 + 2 * (nr))

	/* manufacturer and device ID Constants */
	#define MAN_ID_MAXIM 0x4d
	#define DEV_ID_MAX1668 0x3
	#define DEV_ID_MAX1805 0x5
	#define DEV_ID_MAX1989 0xb

	/* read only mode module parameter */
	static int read_only;
	module_param(read_only, bool, 0);
	MODULE_PARM_DESC(read_only, "Don't set any values, read only mode");

	enum chips { max1668, max1805, max1989 };

	struct max1668_data {
	struct device *hwmon_dev;
	enum chips type;

	struct mutex update_lock;
	char valid; /* !=0 if following fields are valid */
	unsigned long last_updated; /* In jiffies */

	/* 1x local and 4x remote */
	s8 temp_max[5];
	s8 temp_min[5];
	s8 temp[5];
	u16 alarms;
	};

	static struct max1668_data max1668_update_device(struct device dev)
	{
	struct i2c_client *client = to_i2c_client(dev);
	struct max1668_data *data = i2c_get_clientdata(client);
	struct max1668_data *ret = data;
	s32 val;
	int i;

	mutex_lock(&data->update_lock);

	if (data->valid && !time_after(jiffies,
	data->last_updated + HZ + HZ / 2))
	goto abort;

	for (i = 0; i < 5; i++) {
	val = i2c_smbus_read_byte_data(client, MAX1668_REG_TEMP(i));
	if (unlikely(val < 0)) {
	ret = ERR_PTR(val);
	goto abort;
	}
	data->temp[i] = (s8) val;

	val = i2c_smbus_read_byte_data(client, MAX1668_REG_LIMH_RD(i));
	if (unlikely(val < 0)) {
	ret = ERR_PTR(val);
	goto abort;
	}
	data->temp_max[i] = (s8) val;

	val = i2c_smbus_read_byte_data(client, MAX1668_REG_LIML_RD(i));
	if (unlikely(val < 0)) {
	ret = ERR_PTR(val);
	goto abort;
	}
	data->temp_min[i] = (s8) val;
	}

	val = i2c_smbus_read_byte_data(client, MAX1668_REG_STAT1);
	if (unlikely(val < 0)) {
	ret = ERR_PTR(val);
	goto abort;
	}
	data->alarms = val << 8;

	val = i2c_smbus_read_byte_data(client, MAX1668_REG_STAT2);
	if (unlikely(val < 0)) {
	ret = ERR_PTR(val);
	goto abort;
	}
	data->alarms \|= val;

	data->last_updated = jiffies;
	data->valid = 1;
	abort:
	mutex_unlock(&data->update_lock);

	return ret;
	}

	static ssize_t show_temp(struct device *dev,
	struct device_attribute devattr, char buf)
	{
	int index = to_sensor_dev_attr(devattr)->index;
	struct max1668_data *data = max1668_update_device(dev);

	if (IS_ERR(data))
	return PTR_ERR(data);

	return sprintf(buf, "%d\n", data->temp[index] * 1000);
	}

	static ssize_t show_temp_max(struct device *dev,
	struct device_attribute devattr, char buf)
	{
	int index = to_sensor_dev_attr(devattr)->index;
	struct max1668_data *data = max1668_update_device(dev);

	if (IS_ERR(data))
	return PTR_ERR(data);

	return sprintf(buf, "%d\n", data->temp_max[index] * 1000);
	}

	static ssize_t show_temp_min(struct device *dev,
	struct device_attribute devattr, char buf)
	{
	int index = to_sensor_dev_attr(devattr)->index;
	struct max1668_data *data = max1668_update_device(dev);

	if (IS_ERR(data))
	return PTR_ERR(data);

	return sprintf(buf, "%d\n", data->temp_min[index] * 1000);
	}

	static ssize_t show_alarm(struct device dev, struct device_attribute attr,
	char *buf)
	{
	int index = to_sensor_dev_attr(attr)->index;
	struct max1668_data *data = max1668_update_device(dev);

	if (IS_ERR(data))
	return PTR_ERR(data);

	return sprintf(buf, "%u\n", (data->alarms >> index) & 0x1);
	}

	static ssize_t show_fault(struct device *dev,
	struct device_attribute devattr, char buf)
	{
	int index = to_sensor_dev_attr(devattr)->index;
	struct max1668_data *data = max1668_update_device(dev);

	if (IS_ERR(data))
	return PTR_ERR(data);

	return sprintf(buf, "%u\n",
	(data->alarms & (1 << 12)) && data->temp[index] == 127);
	}

	static ssize_t set_temp_max(struct device *dev,
	struct device_attribute *devattr,
	const char *buf, size_t count)
	{
	int index = to_sensor_dev_attr(devattr)->index;
	struct i2c_client *client = to_i2c_client(dev);
	struct max1668_data *data = i2c_get_clientdata(client);
	long temp;
	int ret;

	ret = kstrtol(buf, 10, &temp);
	if (ret < 0)
	return ret;

	mutex_lock(&data->update_lock);
	data->temp_max[index] = SENSORS_LIMIT(temp/1000, -128, 127);
	if (i2c_smbus_write_byte_data(client,
	MAX1668_REG_LIMH_WR(index),
	data->temp_max[index]))
	count = -EIO;
	mutex_unlock(&data->update_lock);

	return count;
	}

	static ssize_t set_temp_min(struct device *dev,
	struct device_attribute *devattr,
	const char *buf, size_t count)
	{
	int index = to_sensor_dev_attr(devattr)->index;
	struct i2c_client *client = to_i2c_client(dev);
	struct max1668_data *data = i2c_get_clientdata(client);
	long temp;
	int ret;

	ret = kstrtol(buf, 10, &temp);
	if (ret < 0)
	return ret;

	mutex_lock(&data->update_lock);
	data->temp_min[index] = SENSORS_LIMIT(temp/1000, -128, 127);
	if (i2c_smbus_write_byte_data(client,
	MAX1668_REG_LIML_WR(index),
	data->temp_max[index]))
	count = -EIO;
	mutex_unlock(&data->update_lock);

	return count;
	}

	static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
	static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp_max,
	set_temp_max, 0);
	static SENSOR_DEVICE_ATTR(temp1_min, S_IRUGO, show_temp_min,
	set_temp_min, 0);
	static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp, NULL, 1);
	static SENSOR_DEVICE_ATTR(temp2_max, S_IRUGO, show_temp_max,
	set_temp_max, 1);
	static SENSOR_DEVICE_ATTR(temp2_min, S_IRUGO, show_temp_min,
	set_temp_min, 1);
	static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_temp, NULL, 2);
	static SENSOR_DEVICE_ATTR(temp3_max, S_IRUGO, show_temp_max,
	set_temp_max, 2);
	static SENSOR_DEVICE_ATTR(temp3_min, S_IRUGO, show_temp_min,
	set_temp_min, 2);
	static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, show_temp, NULL, 3);
	static SENSOR_DEVICE_ATTR(temp4_max, S_IRUGO, show_temp_max,
	set_temp_max, 3);
	static SENSOR_DEVICE_ATTR(temp4_min, S_IRUGO, show_temp_min,
	set_temp_min, 3);
	static SENSOR_DEVICE_ATTR(temp5_input, S_IRUGO, show_temp, NULL, 4);
	static SENSOR_DEVICE_ATTR(temp5_max, S_IRUGO, show_temp_max,
	set_temp_max, 4);
	static SENSOR_DEVICE_ATTR(temp5_min, S_IRUGO, show_temp_min,
	set_temp_min, 4);

	static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 14);
	static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 13);
	static SENSOR_DEVICE_ATTR(temp2_min_alarm, S_IRUGO, show_alarm, NULL, 7);
	static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_alarm, NULL, 6);
	static SENSOR_DEVICE_ATTR(temp3_min_alarm, S_IRUGO, show_alarm, NULL, 5);
	static SENSOR_DEVICE_ATTR(temp3_max_alarm, S_IRUGO, show_alarm, NULL, 4);
	static SENSOR_DEVICE_ATTR(temp4_min_alarm, S_IRUGO, show_alarm, NULL, 3);
	static SENSOR_DEVICE_ATTR(temp4_max_alarm, S_IRUGO, show_alarm, NULL, 2);
	static SENSOR_DEVICE_ATTR(temp5_min_alarm, S_IRUGO, show_alarm, NULL, 1);
	static SENSOR_DEVICE_ATTR(temp5_max_alarm, S_IRUGO, show_alarm, NULL, 0);

	static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_fault, NULL, 1);
	static SENSOR_DEVICE_ATTR(temp3_fault, S_IRUGO, show_fault, NULL, 2);
	static SENSOR_DEVICE_ATTR(temp4_fault, S_IRUGO, show_fault, NULL, 3);
	static SENSOR_DEVICE_ATTR(temp5_fault, S_IRUGO, show_fault, NULL, 4);

	/* Attributes common to MAX1668, MAX1989 and MAX1805 */
	static struct attribute *max1668_attribute_common[] = {
	&sensor_dev_attr_temp1_max.dev_attr.attr,
	&sensor_dev_attr_temp1_min.dev_attr.attr,
	&sensor_dev_attr_temp1_input.dev_attr.attr,
	&sensor_dev_attr_temp2_max.dev_attr.attr,
	&sensor_dev_attr_temp2_min.dev_attr.attr,
	&sensor_dev_attr_temp2_input.dev_attr.attr,
	&sensor_dev_attr_temp3_max.dev_attr.attr,
	&sensor_dev_attr_temp3_min.dev_attr.attr,
	&sensor_dev_attr_temp3_input.dev_attr.attr,

	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
	&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
	&sensor_dev_attr_temp2_min_alarm.dev_attr.attr,
	&sensor_dev_attr_temp3_max_alarm.dev_attr.attr,
	&sensor_dev_attr_temp3_min_alarm.dev_attr.attr,

	&sensor_dev_attr_temp2_fault.dev_attr.attr,
	&sensor_dev_attr_temp3_fault.dev_attr.attr,
	NULL
	};

	/* Attributes not present on MAX1805 */
	static struct attribute *max1668_attribute_unique[] = {
	&sensor_dev_attr_temp4_max.dev_attr.attr,
	&sensor_dev_attr_temp4_min.dev_attr.attr,
	&sensor_dev_attr_temp4_input.dev_attr.attr,
	&sensor_dev_attr_temp5_max.dev_attr.attr,
	&sensor_dev_attr_temp5_min.dev_attr.attr,
	&sensor_dev_attr_temp5_input.dev_attr.attr,

	&sensor_dev_attr_temp4_max_alarm.dev_attr.attr,
	&sensor_dev_attr_temp4_min_alarm.dev_attr.attr,
	&sensor_dev_attr_temp5_max_alarm.dev_attr.attr,
	&sensor_dev_attr_temp5_min_alarm.dev_attr.attr,

	&sensor_dev_attr_temp4_fault.dev_attr.attr,
	&sensor_dev_attr_temp5_fault.dev_attr.attr,
	NULL
	};

	static mode_t max1668_attribute_mode(struct kobject *kobj,
	struct attribute *attr, int index)
	{
	int ret = S_IRUGO;
	if (read_only)
	return ret;
	if (attr == &sensor_dev_attr_temp1_max.dev_attr.attr \|\|
	attr == &sensor_dev_attr_temp2_max.dev_attr.attr \|\|
	attr == &sensor_dev_attr_temp3_max.dev_attr.attr \|\|
	attr == &sensor_dev_attr_temp4_max.dev_attr.attr \|\|
	attr == &sensor_dev_attr_temp5_max.dev_attr.attr \|\|
	attr == &sensor_dev_attr_temp1_min.dev_attr.attr \|\|
	attr == &sensor_dev_attr_temp2_min.dev_attr.attr \|\|
	attr == &sensor_dev_attr_temp3_min.dev_attr.attr \|\|
	attr == &sensor_dev_attr_temp4_min.dev_attr.attr \|\|
	attr == &sensor_dev_attr_temp5_min.dev_attr.attr)
	ret \|= S_IWUSR;
	return ret;
	}

	static const struct attribute_group max1668_group_common = {
	.attrs = max1668_attribute_common,
	.is_visible = max1668_attribute_mode
	};

	static const struct attribute_group max1668_group_unique = {
	.attrs = max1668_attribute_unique,
	.is_visible = max1668_attribute_mode
	};

	/* Return 0 if detection is successful, -ENODEV otherwise */
	static int max1668_detect(struct i2c_client *client,
	struct i2c_board_info *info)
	{
	struct i2c_adapter *adapter = client->adapter;
	const char *type_name;
	int man_id, dev_id;

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

	/* Check for unsupported part */
	man_id = i2c_smbus_read_byte_data(client, MAX1668_REG_MAN_ID);
	if (man_id != MAN_ID_MAXIM)
	return -ENODEV;

	dev_id = i2c_smbus_read_byte_data(client, MAX1668_REG_DEV_ID);
	if (dev_id < 0)
	return -ENODEV;

	type_name = NULL;
	if (dev_id == DEV_ID_MAX1668)
	type_name = "max1668";
	else if (dev_id == DEV_ID_MAX1805)
	type_name = "max1805";
	else if (dev_id == DEV_ID_MAX1989)
	type_name = "max1989";

	if (!type_name)
	return -ENODEV;

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

	return 0;
	}

	static int max1668_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct i2c_adapter *adapter = client->adapter;
	struct max1668_data *data;
	int err;

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

	data = kzalloc(sizeof(struct max1668_data), GFP_KERNEL);
	if (!data)
	return -ENOMEM;

	i2c_set_clientdata(client, data);
	data->type = id->driver_data;
	mutex_init(&data->update_lock);

	/* Register sysfs hooks */
	err = sysfs_create_group(&client->dev.kobj, &max1668_group_common);
	if (err)
	goto error_free;

	if (data->type == max1668 \|\| data->type == max1989) {
	err = sysfs_create_group(&client->dev.kobj,
	&max1668_group_unique);
	if (err)
	goto error_sysrem0;
	}

	data->hwmon_dev = hwmon_device_register(&client->dev);
	if (IS_ERR(data->hwmon_dev)) {
	err = PTR_ERR(data->hwmon_dev);
	goto error_sysrem1;
	}

	return 0;

	error_sysrem1:
	if (data->type == max1668 \|\| data->type == max1989)
	sysfs_remove_group(&client->dev.kobj, &max1668_group_unique);
	error_sysrem0:
	sysfs_remove_group(&client->dev.kobj, &max1668_group_common);
	error_free:
	kfree(data);
	return err;
	}

	static int max1668_remove(struct i2c_client *client)
	{
	struct max1668_data *data = i2c_get_clientdata(client);

	hwmon_device_unregister(data->hwmon_dev);
	if (data->type == max1668 \|\| data->type == max1989)
	sysfs_remove_group(&client->dev.kobj, &max1668_group_unique);

	sysfs_remove_group(&client->dev.kobj, &max1668_group_common);

	kfree(data);
	return 0;
	}

	static const struct i2c_device_id max1668_id[] = {
	{ "max1668", max1668 },
	{ "max1805", max1805 },
	{ "max1989", max1989 },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, max1668_id);

	/* This is the driver that will be inserted */
	static struct i2c_driver max1668_driver = {
	.class = I2C_CLASS_HWMON,
	.driver = {
	.name = "max1668",
	},
	.probe = max1668_probe,
	.remove = max1668_remove,
	.id_table = max1668_id,
	.detect = max1668_detect,
	.address_list = max1668_addr_list,
	};

	static int __init sensors_max1668_init(void)
	{
	return i2c_add_driver(&max1668_driver);
	}

	static void __exit sensors_max1668_exit(void)
	{
	i2c_del_driver(&max1668_driver);
	}

	MODULE_AUTHOR("David George <david.george@ska.ac.za>");
	MODULE_DESCRIPTION("MAX1668 remote temperature sensor driver");
	MODULE_LICENSE("GPL");

	module_init(sensors_max1668_init)
	module_exit(sensors_max1668_exit)