drivers/hwmon/ds1621.c - linux - Git at Google

 /*
     ds1621.c - Part of lm_sensors, Linux kernel modules for hardware
              monitoring
     Christian W. Zuckschwerdt  <zany@triq.net>  2000-11-23
     based on lm75.c by Frodo Looijaard <frodol@dds.nl>
     Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
     the help of Jean Delvare <khali@linux-fr.org>

     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 2 of the License, or
     (at your option) any later version.

     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with this program; if not, write to the Free Software
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/jiffies.h>
 #include <linux/i2c.h>
 #include <linux/hwmon.h>
 #include <linux/hwmon-sysfs.h>
 #include <linux/err.h>
 #include <linux/mutex.h>
 #include <linux/sysfs.h>
 #include "lm75.h"

 /* Addresses to scan */
 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
 					0x4d, 0x4e, 0x4f, I2C_CLIENT_END };

 /* Insmod parameters */
 I2C_CLIENT_INSMOD_1(ds1621);
 static int polarity = -1;
 module_param(polarity, int, 0);
 MODULE_PARM_DESC(polarity, "Output's polarity: 0 = active high, 1 = active low");

 /* Many DS1621 constants specified below */
 /* Config register used for detection         */
 /*  7    6    5    4    3    2    1    0      */
 /* |Done|THF |TLF |NVB | X  | X  |POL |1SHOT| */
 #define DS1621_REG_CONFIG_NVB		0x10
 #define DS1621_REG_CONFIG_POLARITY	0x02
 #define DS1621_REG_CONFIG_1SHOT		0x01
 #define DS1621_REG_CONFIG_DONE		0x80

 /* The DS1621 registers */
 static const u8 DS1621_REG_TEMP[3] = {
 	0xAA,		/* input, word, RO */
 	0xA2,		/* min, word, RW */
 	0xA1,		/* max, word, RW */
 };
 #define DS1621_REG_CONF			0xAC /* byte, RW */
 #define DS1621_COM_START		0xEE /* no data */
 #define DS1621_COM_STOP			0x22 /* no data */

 /* The DS1621 configuration register */
 #define DS1621_ALARM_TEMP_HIGH		0x40
 #define DS1621_ALARM_TEMP_LOW		0x20

 /* Conversions */
 #define ALARMS_FROM_REG(val) ((val) & \
                               (DS1621_ALARM_TEMP_HIGH | DS1621_ALARM_TEMP_LOW))

 /* Each client has this additional data */
 struct ds1621_data {
 	struct device *hwmon_dev;
 	struct mutex update_lock;
 	char valid;			/* !=0 if following fields are valid */
 	unsigned long last_updated;	/* In jiffies */

 	u16 temp[3];			/* Register values, word */
 	u8 conf;			/* Register encoding, combined */
 };

 static int ds1621_probe(struct i2c_client *client,
 			const struct i2c_device_id *id);
 static int ds1621_detect(struct i2c_client *client, int kind,
 			 struct i2c_board_info *info);
 static void ds1621_init_client(struct i2c_client *client);
 static int ds1621_remove(struct i2c_client *client);
 static struct ds1621_data *ds1621_update_client(struct device *dev);

 static const struct i2c_device_id ds1621_id[] = {
 	{ "ds1621", ds1621 },
 	{ "ds1625", ds1621 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, ds1621_id);

 /* This is the driver that will be inserted */
 static struct i2c_driver ds1621_driver = {
 	.class		= I2C_CLASS_HWMON,
 	.driver = {
 		.name	= "ds1621",
 	},
 	.probe		= ds1621_probe,
 	.remove		= ds1621_remove,
 	.id_table	= ds1621_id,
 	.detect		= ds1621_detect,
 	.address_data	= &addr_data,
 };

 /* All registers are word-sized, except for the configuration register.
    DS1621 uses a high-byte first convention, which is exactly opposite to
    the SMBus standard. */
 static int ds1621_read_value(struct i2c_client *client, u8 reg)
 {
 	if (reg == DS1621_REG_CONF)
 		return i2c_smbus_read_byte_data(client, reg);
 	else
 		return swab16(i2c_smbus_read_word_data(client, reg));
 }

 static int ds1621_write_value(struct i2c_client *client, u8 reg, u16 value)
 {
 	if (reg == DS1621_REG_CONF)
 		return i2c_smbus_write_byte_data(client, reg, value);
 	else
 		return i2c_smbus_write_word_data(client, reg, swab16(value));
 }

 static void ds1621_init_client(struct i2c_client *client)
 {
 	int reg = ds1621_read_value(client, DS1621_REG_CONF);
 	/* switch to continuous conversion mode */
 	reg &= ~ DS1621_REG_CONFIG_1SHOT;

 	/* setup output polarity */
 	if (polarity == 0)
 		reg &= ~DS1621_REG_CONFIG_POLARITY;
 	else if (polarity == 1)
 		reg |= DS1621_REG_CONFIG_POLARITY;

 	ds1621_write_value(client, DS1621_REG_CONF, reg);

 	/* start conversion */
 	i2c_smbus_write_byte(client, DS1621_COM_START);
 }

 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
 			 char *buf)
 {
 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 	struct ds1621_data *data = ds1621_update_client(dev);
 	return sprintf(buf, "%d\n",
 		       LM75_TEMP_FROM_REG(data->temp[attr->index]));
 }

 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
 			const char *buf, size_t count)
 {
 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 	struct i2c_client *client = to_i2c_client(dev);
 	struct ds1621_data *data = ds1621_update_client(dev);
 	u16 val = LM75_TEMP_TO_REG(simple_strtol(buf, NULL, 10));

 	mutex_lock(&data->update_lock);
 	data->temp[attr->index] = val;
 	ds1621_write_value(client, DS1621_REG_TEMP[attr->index],
 			   data->temp[attr->index]);
 	mutex_unlock(&data->update_lock);
 	return count;
 }

 static ssize_t show_alarms(struct device *dev, struct device_attribute *da,
 			   char *buf)
 {
 	struct ds1621_data *data = ds1621_update_client(dev);
 	return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
 }

 static ssize_t show_alarm(struct device *dev, struct device_attribute *da,
 			  char *buf)
 {
 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 	struct ds1621_data *data = ds1621_update_client(dev);
 	return sprintf(buf, "%d\n", !!(data->conf & attr->index));
 }

 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 1);
 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 2);
 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
 		DS1621_ALARM_TEMP_LOW);
 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
 		DS1621_ALARM_TEMP_HIGH);

 static struct attribute *ds1621_attributes[] = {
 	&sensor_dev_attr_temp1_input.dev_attr.attr,
 	&sensor_dev_attr_temp1_min.dev_attr.attr,
 	&sensor_dev_attr_temp1_max.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,
 	NULL
 };

 static const struct attribute_group ds1621_group = {
 	.attrs = ds1621_attributes,
 };


 /* Return 0 if detection is successful, -ENODEV otherwise */
 static int ds1621_detect(struct i2c_client *client, int kind,
 			 struct i2c_board_info *info)
 {
 	struct i2c_adapter *adapter = client->adapter;
 	int conf, temp;
 	int i;

 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 				     | I2C_FUNC_SMBUS_WORD_DATA
 				     | I2C_FUNC_SMBUS_WRITE_BYTE))
 		return -ENODEV;

 	/* Now, we do the remaining detection. It is lousy. */
 	if (kind < 0) {
 		/* The NVB bit should be low if no EEPROM write has been
 		   requested during the latest 10ms, which is highly
 		   improbable in our case. */
 		conf = ds1621_read_value(client, DS1621_REG_CONF);
 		if (conf & DS1621_REG_CONFIG_NVB)
 			return -ENODEV;
 		/* The 7 lowest bits of a temperature should always be 0. */
 		for (i = 0; i < ARRAY_SIZE(DS1621_REG_TEMP); i++) {
 			temp = ds1621_read_value(client, DS1621_REG_TEMP[i]);
 			if (temp & 0x007f)
 				return -ENODEV;
 		}
 	}

 	strlcpy(info->type, "ds1621", I2C_NAME_SIZE);

 	return 0;
 }

 static int ds1621_probe(struct i2c_client *client,
 			const struct i2c_device_id *id)
 {
 	struct ds1621_data *data;
 	int err;

 	data = kzalloc(sizeof(struct ds1621_data), GFP_KERNEL);
 	if (!data) {
 		err = -ENOMEM;
 		goto exit;
 	}

 	i2c_set_clientdata(client, data);
 	mutex_init(&data->update_lock);

 	/* Initialize the DS1621 chip */
 	ds1621_init_client(client);

 	/* Register sysfs hooks */
 	if ((err = sysfs_create_group(&client->dev.kobj, &ds1621_group)))
 		goto exit_free;

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

 	return 0;

       exit_remove_files:
 	sysfs_remove_group(&client->dev.kobj, &ds1621_group);
       exit_free:
 	kfree(data);
       exit:
 	return err;
 }

 static int ds1621_remove(struct i2c_client *client)
 {
 	struct ds1621_data *data = i2c_get_clientdata(client);

 	hwmon_device_unregister(data->hwmon_dev);
 	sysfs_remove_group(&client->dev.kobj, &ds1621_group);

 	kfree(data);

 	return 0;
 }


 static struct ds1621_data *ds1621_update_client(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct ds1621_data *data = i2c_get_clientdata(client);
 	u8 new_conf;

 	mutex_lock(&data->update_lock);

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

 		dev_dbg(&client->dev, "Starting ds1621 update\n");

 		data->conf = ds1621_read_value(client, DS1621_REG_CONF);

 		for (i = 0; i < ARRAY_SIZE(data->temp); i++)
 			data->temp[i] = ds1621_read_value(client,
 							  DS1621_REG_TEMP[i]);

 		/* reset alarms if necessary */
 		new_conf = data->conf;
 		if (data->temp[0] > data->temp[1])	/* input > min */
 			new_conf &= ~DS1621_ALARM_TEMP_LOW;
 		if (data->temp[0] < data->temp[2])	/* input < max */
 			new_conf &= ~DS1621_ALARM_TEMP_HIGH;
 		if (data->conf != new_conf)
 			ds1621_write_value(client, DS1621_REG_CONF,
 					   new_conf);

 		data->last_updated = jiffies;
 		data->valid = 1;
 	}

 	mutex_unlock(&data->update_lock);

 	return data;
 }

 static int __init ds1621_init(void)
 {
 	return i2c_add_driver(&ds1621_driver);
 }

 static void __exit ds1621_exit(void)
 {
 	i2c_del_driver(&ds1621_driver);
 }


 MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
 MODULE_DESCRIPTION("DS1621 driver");
 MODULE_LICENSE("GPL");

 module_init(ds1621_init);
 module_exit(ds1621_exit);
	/*
	ds1621.c - Part of lm_sensors, Linux kernel modules for hardware
	monitoring
	Christian W. Zuckschwerdt <zany@triq.net> 2000-11-23
	based on lm75.c by Frodo Looijaard <frodol@dds.nl>
	Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
	the help of Jean Delvare <khali@linux-fr.org>

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	*/

	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/slab.h>
	#include <linux/jiffies.h>
	#include <linux/i2c.h>
	#include <linux/hwmon.h>
	#include <linux/hwmon-sysfs.h>
	#include <linux/err.h>
	#include <linux/mutex.h>
	#include <linux/sysfs.h>
	#include "lm75.h"

	/* Addresses to scan */
	static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
	0x4d, 0x4e, 0x4f, I2C_CLIENT_END };

	/* Insmod parameters */
	I2C_CLIENT_INSMOD_1(ds1621);
	static int polarity = -1;
	module_param(polarity, int, 0);
	MODULE_PARM_DESC(polarity, "Output's polarity: 0 = active high, 1 = active low");

	/* Many DS1621 constants specified below */
	/* Config register used for detection */
	/* 7 6 5 4 3 2 1 0 */
	/* \|Done\|THF \|TLF \|NVB \| X \| X \|POL \|1SHOT\| */
	#define DS1621_REG_CONFIG_NVB 0x10
	#define DS1621_REG_CONFIG_POLARITY 0x02
	#define DS1621_REG_CONFIG_1SHOT 0x01
	#define DS1621_REG_CONFIG_DONE 0x80

	/* The DS1621 registers */
	static const u8 DS1621_REG_TEMP[3] = {
	0xAA, /* input, word, RO */
	0xA2, /* min, word, RW */
	0xA1, /* max, word, RW */
	};
	#define DS1621_REG_CONF 0xAC /* byte, RW */
	#define DS1621_COM_START 0xEE /* no data */
	#define DS1621_COM_STOP 0x22 /* no data */

	/* The DS1621 configuration register */
	#define DS1621_ALARM_TEMP_HIGH 0x40
	#define DS1621_ALARM_TEMP_LOW 0x20

	/* Conversions */
	#define ALARMS_FROM_REG(val) ((val) & \
	(DS1621_ALARM_TEMP_HIGH \| DS1621_ALARM_TEMP_LOW))

	/* Each client has this additional data */
	struct ds1621_data {
	struct device *hwmon_dev;
	struct mutex update_lock;
	char valid; /* !=0 if following fields are valid */
	unsigned long last_updated; /* In jiffies */

	u16 temp[3]; /* Register values, word */
	u8 conf; /* Register encoding, combined */
	};

	static int ds1621_probe(struct i2c_client *client,
	const struct i2c_device_id *id);
	static int ds1621_detect(struct i2c_client *client, int kind,
	struct i2c_board_info *info);
	static void ds1621_init_client(struct i2c_client *client);
	static int ds1621_remove(struct i2c_client *client);
	static struct ds1621_data ds1621_update_client(struct device dev);

	static const struct i2c_device_id ds1621_id[] = {
	{ "ds1621", ds1621 },
	{ "ds1625", ds1621 },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, ds1621_id);

	/* This is the driver that will be inserted */
	static struct i2c_driver ds1621_driver = {
	.class = I2C_CLASS_HWMON,
	.driver = {
	.name = "ds1621",
	},
	.probe = ds1621_probe,
	.remove = ds1621_remove,
	.id_table = ds1621_id,
	.detect = ds1621_detect,
	.address_data = &addr_data,
	};

	/* All registers are word-sized, except for the configuration register.
	DS1621 uses a high-byte first convention, which is exactly opposite to
	the SMBus standard. */
	static int ds1621_read_value(struct i2c_client *client, u8 reg)
	{
	if (reg == DS1621_REG_CONF)
	return i2c_smbus_read_byte_data(client, reg);
	else
	return swab16(i2c_smbus_read_word_data(client, reg));
	}

	static int ds1621_write_value(struct i2c_client *client, u8 reg, u16 value)
	{
	if (reg == DS1621_REG_CONF)
	return i2c_smbus_write_byte_data(client, reg, value);
	else
	return i2c_smbus_write_word_data(client, reg, swab16(value));
	}

	static void ds1621_init_client(struct i2c_client *client)
	{
	int reg = ds1621_read_value(client, DS1621_REG_CONF);
	/* switch to continuous conversion mode */
	reg &= ~ DS1621_REG_CONFIG_1SHOT;

	/* setup output polarity */
	if (polarity == 0)
	reg &= ~DS1621_REG_CONFIG_POLARITY;
	else if (polarity == 1)
	reg \|= DS1621_REG_CONFIG_POLARITY;

	ds1621_write_value(client, DS1621_REG_CONF, reg);

	/* start conversion */
	i2c_smbus_write_byte(client, DS1621_COM_START);
	}

	static ssize_t show_temp(struct device dev, struct device_attribute da,
	char *buf)
	{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct ds1621_data *data = ds1621_update_client(dev);
	return sprintf(buf, "%d\n",
	LM75_TEMP_FROM_REG(data->temp[attr->index]));
	}

	static ssize_t set_temp(struct device dev, struct device_attribute da,
	const char *buf, size_t count)
	{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct i2c_client *client = to_i2c_client(dev);
	struct ds1621_data *data = ds1621_update_client(dev);
	u16 val = LM75_TEMP_TO_REG(simple_strtol(buf, NULL, 10));

	mutex_lock(&data->update_lock);
	data->temp[attr->index] = val;
	ds1621_write_value(client, DS1621_REG_TEMP[attr->index],
	data->temp[attr->index]);
	mutex_unlock(&data->update_lock);
	return count;
	}

	static ssize_t show_alarms(struct device dev, struct device_attribute da,
	char *buf)
	{
	struct ds1621_data *data = ds1621_update_client(dev);
	return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
	}

	static ssize_t show_alarm(struct device dev, struct device_attribute da,
	char *buf)
	{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct ds1621_data *data = ds1621_update_client(dev);
	return sprintf(buf, "%d\n", !!(data->conf & attr->index));
	}

	static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
	static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
	static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR \| S_IRUGO, show_temp, set_temp, 1);
	static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR \| S_IRUGO, show_temp, set_temp, 2);
	static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
	DS1621_ALARM_TEMP_LOW);
	static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
	DS1621_ALARM_TEMP_HIGH);

	static struct attribute *ds1621_attributes[] = {
	&sensor_dev_attr_temp1_input.dev_attr.attr,
	&sensor_dev_attr_temp1_min.dev_attr.attr,
	&sensor_dev_attr_temp1_max.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,
	NULL
	};

	static const struct attribute_group ds1621_group = {
	.attrs = ds1621_attributes,
	};


	/* Return 0 if detection is successful, -ENODEV otherwise */
	static int ds1621_detect(struct i2c_client *client, int kind,
	struct i2c_board_info *info)
	{
	struct i2c_adapter *adapter = client->adapter;
	int conf, temp;
	int i;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
	\| I2C_FUNC_SMBUS_WORD_DATA
	\| I2C_FUNC_SMBUS_WRITE_BYTE))
	return -ENODEV;

	/* Now, we do the remaining detection. It is lousy. */
	if (kind < 0) {
	/* The NVB bit should be low if no EEPROM write has been
	requested during the latest 10ms, which is highly
	improbable in our case. */
	conf = ds1621_read_value(client, DS1621_REG_CONF);
	if (conf & DS1621_REG_CONFIG_NVB)
	return -ENODEV;
	/* The 7 lowest bits of a temperature should always be 0. */
	for (i = 0; i < ARRAY_SIZE(DS1621_REG_TEMP); i++) {
	temp = ds1621_read_value(client, DS1621_REG_TEMP[i]);
	if (temp & 0x007f)
	return -ENODEV;
	}
	}

	strlcpy(info->type, "ds1621", I2C_NAME_SIZE);

	return 0;
	}

	static int ds1621_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct ds1621_data *data;
	int err;

	data = kzalloc(sizeof(struct ds1621_data), GFP_KERNEL);
	if (!data) {
	err = -ENOMEM;
	goto exit;
	}

	i2c_set_clientdata(client, data);
	mutex_init(&data->update_lock);

	/* Initialize the DS1621 chip */
	ds1621_init_client(client);

	/* Register sysfs hooks */
	if ((err = sysfs_create_group(&client->dev.kobj, &ds1621_group)))
	goto exit_free;

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

	return 0;

	exit_remove_files:
	sysfs_remove_group(&client->dev.kobj, &ds1621_group);
	exit_free:
	kfree(data);
	exit:
	return err;
	}

	static int ds1621_remove(struct i2c_client *client)
	{
	struct ds1621_data *data = i2c_get_clientdata(client);

	hwmon_device_unregister(data->hwmon_dev);
	sysfs_remove_group(&client->dev.kobj, &ds1621_group);

	kfree(data);

	return 0;
	}


	static struct ds1621_data ds1621_update_client(struct device dev)
	{
	struct i2c_client *client = to_i2c_client(dev);
	struct ds1621_data *data = i2c_get_clientdata(client);
	u8 new_conf;

	mutex_lock(&data->update_lock);

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

	dev_dbg(&client->dev, "Starting ds1621 update\n");

	data->conf = ds1621_read_value(client, DS1621_REG_CONF);

	for (i = 0; i < ARRAY_SIZE(data->temp); i++)
	data->temp[i] = ds1621_read_value(client,
	DS1621_REG_TEMP[i]);

	/* reset alarms if necessary */
	new_conf = data->conf;
	if (data->temp[0] > data->temp[1]) /* input > min */
	new_conf &= ~DS1621_ALARM_TEMP_LOW;
	if (data->temp[0] < data->temp[2]) /* input < max */
	new_conf &= ~DS1621_ALARM_TEMP_HIGH;
	if (data->conf != new_conf)
	ds1621_write_value(client, DS1621_REG_CONF,
	new_conf);

	data->last_updated = jiffies;
	data->valid = 1;
	}

	mutex_unlock(&data->update_lock);

	return data;
	}

	static int __init ds1621_init(void)
	{
	return i2c_add_driver(&ds1621_driver);
	}

	static void __exit ds1621_exit(void)
	{
	i2c_del_driver(&ds1621_driver);
	}


	MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
	MODULE_DESCRIPTION("DS1621 driver");
	MODULE_LICENSE("GPL");

	module_init(ds1621_init);
	module_exit(ds1621_exit);