[deliverable/linux.git] / drivers / hwmon / lm77.c

/*
    lm77.c - Part of lm_sensors, Linux kernel modules for hardware
             monitoring

    Copyright (c) 2004  Andras BALI <drewie@freemail.hu>

    Heavily based on lm75.c by Frodo Looijaard <frodol@dds.nl>.  The LM77
    is a temperature sensor and thermal window comparator with 0.5 deg
    resolution made by National Semiconductor.  Complete datasheet can be
    obtained at their site:
       http://www.national.com/pf/LM/LM77.html

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

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

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

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

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

/* Insmod parameters */
I2C_CLIENT_INSMOD_1(lm77);

/* The LM77 registers */
#define LM77_REG_TEMP		0x00
#define LM77_REG_CONF		0x01
#define LM77_REG_TEMP_HYST	0x02
#define LM77_REG_TEMP_CRIT	0x03
#define LM77_REG_TEMP_MIN	0x04
#define LM77_REG_TEMP_MAX	0x05

/* Each client has this additional data */
struct lm77_data {
	struct device 		*hwmon_dev;
	struct mutex		update_lock;
	char			valid;
	unsigned long		last_updated;	/* In jiffies */
	int			temp_input;	/* Temperatures */
	int			temp_crit;
	int			temp_min;
	int			temp_max;
	int			temp_hyst;
	u8			alarms;
};

static int lm77_probe(struct i2c_client *client,
		      const struct i2c_device_id *id);
static int lm77_detect(struct i2c_client *client, struct i2c_board_info *info);
static void lm77_init_client(struct i2c_client *client);
static int lm77_remove(struct i2c_client *client);
static u16 lm77_read_value(struct i2c_client *client, u8 reg);
static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value);

static struct lm77_data *lm77_update_device(struct device *dev);


static const struct i2c_device_id lm77_id[] = {
	{ "lm77", lm77 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, lm77_id);

/* This is the driver that will be inserted */
static struct i2c_driver lm77_driver = {
	.class		= I2C_CLASS_HWMON,
	.driver = {
		.name	= "lm77",
	},
	.probe		= lm77_probe,
	.remove		= lm77_remove,
	.id_table	= lm77_id,
	.detect		= lm77_detect,
	.address_list	= normal_i2c,
};

/* straight from the datasheet */
#define LM77_TEMP_MIN (-55000)
#define LM77_TEMP_MAX 125000

/* In the temperature registers, the low 3 bits are not part of the
   temperature values; they are the status bits. */
static inline s16 LM77_TEMP_TO_REG(int temp)
{
	int ntemp = SENSORS_LIMIT(temp, LM77_TEMP_MIN, LM77_TEMP_MAX);
	return (ntemp / 500) * 8;
}

static inline int LM77_TEMP_FROM_REG(s16 reg)
{
	return (reg / 8) * 500;
}

/* sysfs stuff */

/* read routines for temperature limits */
#define show(value)	\
static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf)	\
{								\
	struct lm77_data *data = lm77_update_device(dev);	\
	return sprintf(buf, "%d\n", data->value);		\
}

show(temp_input);
show(temp_crit);
show(temp_min);
show(temp_max);

/* read routines for hysteresis values */
static ssize_t show_temp_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct lm77_data *data = lm77_update_device(dev);
	return sprintf(buf, "%d\n", data->temp_crit - data->temp_hyst);
}
static ssize_t show_temp_min_hyst(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct lm77_data *data = lm77_update_device(dev);
	return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst);
}
static ssize_t show_temp_max_hyst(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct lm77_data *data = lm77_update_device(dev);
	return sprintf(buf, "%d\n", data->temp_max - data->temp_hyst);
}

/* write routines */
#define set(value, reg)	\
static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)	\
{										\
	struct i2c_client *client = to_i2c_client(dev);				\
	struct lm77_data *data = i2c_get_clientdata(client);			\
	long val = simple_strtol(buf, NULL, 10);				\
										\
	mutex_lock(&data->update_lock);						\
	data->value = val;				\
	lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value));		\
	mutex_unlock(&data->update_lock);					\
	return count;								\
}

set(temp_min, LM77_REG_TEMP_MIN);
set(temp_max, LM77_REG_TEMP_MAX);

/* hysteresis is stored as a relative value on the chip, so it has to be
   converted first */
static ssize_t set_temp_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct lm77_data *data = i2c_get_clientdata(client);
	unsigned long val = simple_strtoul(buf, NULL, 10);

	mutex_lock(&data->update_lock);
	data->temp_hyst = data->temp_crit - val;
	lm77_write_value(client, LM77_REG_TEMP_HYST,
			 LM77_TEMP_TO_REG(data->temp_hyst));
	mutex_unlock(&data->update_lock);
	return count;
}

/* preserve hysteresis when setting T_crit */
static ssize_t set_temp_crit(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct lm77_data *data = i2c_get_clientdata(client);
	long val = simple_strtoul(buf, NULL, 10);
	int oldcrithyst;
	
	mutex_lock(&data->update_lock);
	oldcrithyst = data->temp_crit - data->temp_hyst;
	data->temp_crit = val;
	data->temp_hyst = data->temp_crit - oldcrithyst;
	lm77_write_value(client, LM77_REG_TEMP_CRIT,
			 LM77_TEMP_TO_REG(data->temp_crit));
	lm77_write_value(client, LM77_REG_TEMP_HYST,
			 LM77_TEMP_TO_REG(data->temp_hyst));
	mutex_unlock(&data->update_lock);
	return count;
}

static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
			  char *buf)
{
	int bitnr = to_sensor_dev_attr(attr)->index;
	struct lm77_data *data = lm77_update_device(dev);
	return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1);
}

static DEVICE_ATTR(temp1_input, S_IRUGO,
		   show_temp_input, NULL);
static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO,
		   show_temp_crit, set_temp_crit);
static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
		   show_temp_min, set_temp_min);
static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
		   show_temp_max, set_temp_max);

static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO,
		   show_temp_crit_hyst, set_temp_crit_hyst);
static DEVICE_ATTR(temp1_min_hyst, S_IRUGO,
		   show_temp_min_hyst, NULL);
static DEVICE_ATTR(temp1_max_hyst, S_IRUGO,
		   show_temp_max_hyst, NULL);

static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);

static struct attribute *lm77_attributes[] = {
	&dev_attr_temp1_input.attr,
	&dev_attr_temp1_crit.attr,
	&dev_attr_temp1_min.attr,
	&dev_attr_temp1_max.attr,
	&dev_attr_temp1_crit_hyst.attr,
	&dev_attr_temp1_min_hyst.attr,
	&dev_attr_temp1_max_hyst.attr,
	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
	NULL
};

static const struct attribute_group lm77_group = {
	.attrs = lm77_attributes,
};

/* Return 0 if detection is successful, -ENODEV otherwise */
static int lm77_detect(struct i2c_client *new_client,
		       struct i2c_board_info *info)
{
	struct i2c_adapter *adapter = new_client->adapter;
	int i, cur, conf, hyst, crit, min, max;

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

	/* Here comes the remaining detection.  Since the LM77 has no
	   register dedicated to identification, we have to rely on the
	   following tricks:

	   1. the high 4 bits represent the sign and thus they should
	      always be the same
	   2. the high 3 bits are unused in the configuration register
	   3. addresses 0x06 and 0x07 return the last read value
	   4. registers cycling over 8-address boundaries

	   Word-sized registers are high-byte first. */

	/* addresses cycling */
	cur = i2c_smbus_read_word_data(new_client, 0);
	conf = i2c_smbus_read_byte_data(new_client, 1);
	hyst = i2c_smbus_read_word_data(new_client, 2);
	crit = i2c_smbus_read_word_data(new_client, 3);
	min = i2c_smbus_read_word_data(new_client, 4);
	max = i2c_smbus_read_word_data(new_client, 5);
	for (i = 8; i <= 0xff; i += 8) {
		if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
		 || i2c_smbus_read_word_data(new_client, i + 2) != hyst
		 || i2c_smbus_read_word_data(new_client, i + 3) != crit
		 || i2c_smbus_read_word_data(new_client, i + 4) != min
		 || i2c_smbus_read_word_data(new_client, i + 5) != max)
			return -ENODEV;
	}

	/* sign bits */
	if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0)
	 || ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0)
	 || ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0)
	 || ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0)
	 || ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0))
		return -ENODEV;

	/* unused bits */
	if (conf & 0xe0)
		return -ENODEV;

	/* 0x06 and 0x07 return the last read value */
	cur = i2c_smbus_read_word_data(new_client, 0);
	if (i2c_smbus_read_word_data(new_client, 6) != cur
	 || i2c_smbus_read_word_data(new_client, 7) != cur)
		return -ENODEV;
	hyst = i2c_smbus_read_word_data(new_client, 2);
	if (i2c_smbus_read_word_data(new_client, 6) != hyst
	 || i2c_smbus_read_word_data(new_client, 7) != hyst)
		return -ENODEV;
	min = i2c_smbus_read_word_data(new_client, 4);
	if (i2c_smbus_read_word_data(new_client, 6) != min
	 || i2c_smbus_read_word_data(new_client, 7) != min)
		return -ENODEV;

	strlcpy(info->type, "lm77", I2C_NAME_SIZE);

	return 0;
}

static int lm77_probe(struct i2c_client *new_client,
		      const struct i2c_device_id *id)
{
	struct lm77_data *data;
	int err;

	data = kzalloc(sizeof(struct lm77_data), GFP_KERNEL);
	if (!data) {
		err = -ENOMEM;
		goto exit;
	}

	i2c_set_clientdata(new_client, data);
	data->valid = 0;
	mutex_init(&data->update_lock);

	/* Initialize the LM77 chip */
	lm77_init_client(new_client);

	/* Register sysfs hooks */
	if ((err = sysfs_create_group(&new_client->dev.kobj, &lm77_group)))
		goto exit_free;

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

	return 0;

exit_remove:
	sysfs_remove_group(&new_client->dev.kobj, &lm77_group);
exit_free:
	kfree(data);
exit:
	return err;
}

static int lm77_remove(struct i2c_client *client)
{
	struct lm77_data *data = i2c_get_clientdata(client);
	hwmon_device_unregister(data->hwmon_dev);
	sysfs_remove_group(&client->dev.kobj, &lm77_group);
	kfree(data);
	return 0;
}

/* All registers are word-sized, except for the configuration register.
   The LM77 uses the high-byte first convention. */
static u16 lm77_read_value(struct i2c_client *client, u8 reg)
{
	if (reg == LM77_REG_CONF)
		return i2c_smbus_read_byte_data(client, reg);
	else
		return swab16(i2c_smbus_read_word_data(client, reg));
}

static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value)
{
	if (reg == LM77_REG_CONF)
		return i2c_smbus_write_byte_data(client, reg, value);
	else
		return i2c_smbus_write_word_data(client, reg, swab16(value));
}

static void lm77_init_client(struct i2c_client *client)
{
	/* Initialize the LM77 chip - turn off shutdown mode */
	int conf = lm77_read_value(client, LM77_REG_CONF);
	if (conf & 1)
		lm77_write_value(client, LM77_REG_CONF, conf & 0xfe);
}

static struct lm77_data *lm77_update_device(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct lm77_data *data = i2c_get_clientdata(client);

	mutex_lock(&data->update_lock);

	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
	    || !data->valid) {
		dev_dbg(&client->dev, "Starting lm77 update\n");
		data->temp_input =
			LM77_TEMP_FROM_REG(lm77_read_value(client,
							   LM77_REG_TEMP));
		data->temp_hyst =
			LM77_TEMP_FROM_REG(lm77_read_value(client,
							   LM77_REG_TEMP_HYST));
		data->temp_crit =
			LM77_TEMP_FROM_REG(lm77_read_value(client,
							   LM77_REG_TEMP_CRIT));
		data->temp_min =
			LM77_TEMP_FROM_REG(lm77_read_value(client,
							   LM77_REG_TEMP_MIN));
		data->temp_max =
			LM77_TEMP_FROM_REG(lm77_read_value(client,
							   LM77_REG_TEMP_MAX));
		data->alarms =
			lm77_read_value(client, LM77_REG_TEMP) & 0x0007;
		data->last_updated = jiffies;
		data->valid = 1;
	}

	mutex_unlock(&data->update_lock);

	return data;
}

static int __init sensors_lm77_init(void)
{
	return i2c_add_driver(&lm77_driver);
}

static void __exit sensors_lm77_exit(void)
{
	i2c_del_driver(&lm77_driver);
}

MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>");
MODULE_DESCRIPTION("LM77 driver");
MODULE_LICENSE("GPL");

module_init(sensors_lm77_init);
module_exit(sensors_lm77_exit);
Commit	Line	Data
1da177e4 LT	1	/*
	2	lm77.c - Part of lm_sensors, Linux kernel modules for hardware
	3	monitoring
	4
	5	Copyright (c) 2004 Andras BALI <drewie@freemail.hu>
	6
	7	Heavily based on lm75.c by Frodo Looijaard <frodol@dds.nl>. The LM77
	8	is a temperature sensor and thermal window comparator with 0.5 deg
	9	resolution made by National Semiconductor. Complete datasheet can be
	10	obtained at their site:
	11	http://www.national.com/pf/LM/LM77.html
	12
	13	This program is free software; you can redistribute it and/or modify
	14	it under the terms of the GNU General Public License as published by
	15	the Free Software Foundation; either version 2 of the License, or
	16	(at your option) any later version.
	17
	18	This program is distributed in the hope that it will be useful,
	19	but WITHOUT ANY WARRANTY; without even the implied warranty of
	20	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	21	GNU General Public License for more details.
	22
	23	You should have received a copy of the GNU General Public License
	24	along with this program; if not, write to the Free Software
	25	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	26	*/
	27
1da177e4 LT	28	#include <linux/module.h>
	29	#include <linux/init.h>
	30	#include <linux/slab.h>
	31	#include <linux/jiffies.h>
	32	#include <linux/i2c.h>
943b0830	33	#include <linux/hwmon.h>
1f52af0f	34	#include <linux/hwmon-sysfs.h>
943b0830	35	#include <linux/err.h>
9a61bf63	36	#include <linux/mutex.h>
1da177e4 LT	37
1da177e4 LT	38	/* Addresses to scan */
25e9c86d MH	39	static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
25e9c86d MH	40	I2C_CLIENT_END };
1da177e4 LT	41
1da177e4 LT	42	/* Insmod parameters */
f4b50261	43	I2C_CLIENT_INSMOD_1(lm77);
1da177e4 LT	44
	45	/* The LM77 registers */
	46	#define LM77_REG_TEMP 0x00
	47	#define LM77_REG_CONF 0x01
	48	#define LM77_REG_TEMP_HYST 0x02
	49	#define LM77_REG_TEMP_CRIT 0x03
	50	#define LM77_REG_TEMP_MIN 0x04
	51	#define LM77_REG_TEMP_MAX 0x05
	52
	53	/* Each client has this additional data */
	54	struct lm77_data {
1beeffe4	55	struct device *hwmon_dev;
9a61bf63	56	struct mutex update_lock;
1da177e4 LT	57	char valid;
	58	unsigned long last_updated; /* In jiffies */
	59	int temp_input; /* Temperatures */
	60	int temp_crit;
	61	int temp_min;
	62	int temp_max;
	63	int temp_hyst;
	64	u8 alarms;
	65	};
	66
a189dd62 JD	67	static int lm77_probe(struct i2c_client *client,
a189dd62 JD	68	const struct i2c_device_id *id);
310ec792	69	static int lm77_detect(struct i2c_client client, struct i2c_board_info info);
1da177e4	70	static void lm77_init_client(struct i2c_client *client);
a189dd62	71	static int lm77_remove(struct i2c_client *client);
1da177e4 LT	72	static u16 lm77_read_value(struct i2c_client *client, u8 reg);
	73	static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value);
	74
	75	static struct lm77_data lm77_update_device(struct device dev);
	76
	77
a189dd62 JD	78	static const struct i2c_device_id lm77_id[] = {
	79	{ "lm77", lm77 },
	80	{ }
	81	};
	82	MODULE_DEVICE_TABLE(i2c, lm77_id);
	83
1da177e4 LT	84	/* This is the driver that will be inserted */
1da177e4 LT	85	static struct i2c_driver lm77_driver = {
a189dd62	86	.class = I2C_CLASS_HWMON,
cdaf7934	87	.driver = {
cdaf7934 LR	88	.name = "lm77",
cdaf7934 LR	89	},
a189dd62 JD	90	.probe = lm77_probe,
	91	.remove = lm77_remove,
	92	.id_table = lm77_id,
	93	.detect = lm77_detect,
c3813d6a	94	.address_list = normal_i2c,
1da177e4 LT	95	};
	96
	97	/* straight from the datasheet */
	98	#define LM77_TEMP_MIN (-55000)
	99	#define LM77_TEMP_MAX 125000
	100
	101	/* In the temperature registers, the low 3 bits are not part of the
	102	temperature values; they are the status bits. */
413b6451	103	static inline s16 LM77_TEMP_TO_REG(int temp)
1da177e4 LT	104	{
1da177e4 LT	105	int ntemp = SENSORS_LIMIT(temp, LM77_TEMP_MIN, LM77_TEMP_MAX);
413b6451	106	return (ntemp / 500) * 8;
1da177e4 LT	107	}
1da177e4 LT	108
413b6451	109	static inline int LM77_TEMP_FROM_REG(s16 reg)
1da177e4	110	{
413b6451	111	return (reg / 8) * 500;
1da177e4 LT	112	}
	113
	114	/* sysfs stuff */
	115
	116	/* read routines for temperature limits */
	117	#define show(value) \
8627f9ba	118	static ssize_t show_##value(struct device dev, struct device_attribute attr, char *buf) \
1da177e4 LT	119	{ \
	120	struct lm77_data *data = lm77_update_device(dev); \
	121	return sprintf(buf, "%d\n", data->value); \
	122	}
	123
	124	show(temp_input);
	125	show(temp_crit);
	126	show(temp_min);
	127	show(temp_max);
1da177e4 LT	128
1da177e4 LT	129	/* read routines for hysteresis values */
8627f9ba	130	static ssize_t show_temp_crit_hyst(struct device dev, struct device_attribute attr, char *buf)
1da177e4 LT	131	{
	132	struct lm77_data *data = lm77_update_device(dev);
	133	return sprintf(buf, "%d\n", data->temp_crit - data->temp_hyst);
	134	}
8627f9ba	135	static ssize_t show_temp_min_hyst(struct device dev, struct device_attribute attr, char *buf)
1da177e4 LT	136	{
	137	struct lm77_data *data = lm77_update_device(dev);
	138	return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst);
	139	}
8627f9ba	140	static ssize_t show_temp_max_hyst(struct device dev, struct device_attribute attr, char *buf)
1da177e4 LT	141	{
	142	struct lm77_data *data = lm77_update_device(dev);
	143	return sprintf(buf, "%d\n", data->temp_max - data->temp_hyst);
	144	}
	145
	146	/* write routines */
	147	#define set(value, reg) \
8627f9ba	148	static ssize_t set_##value(struct device dev, struct device_attribute attr, const char *buf, size_t count) \
1da177e4 LT	149	{ \
	150	struct i2c_client *client = to_i2c_client(dev); \
	151	struct lm77_data *data = i2c_get_clientdata(client); \
5bfedac0	152	long val = simple_strtol(buf, NULL, 10); \
1da177e4	153	\
9a61bf63	154	mutex_lock(&data->update_lock); \
1da177e4 LT	155	data->value = val; \
1da177e4 LT	156	lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value)); \
9a61bf63	157	mutex_unlock(&data->update_lock); \
1da177e4 LT	158	return count; \
	159	}
	160
	161	set(temp_min, LM77_REG_TEMP_MIN);
	162	set(temp_max, LM77_REG_TEMP_MAX);
	163
	164	/* hysteresis is stored as a relative value on the chip, so it has to be
	165	converted first */
8627f9ba	166	static ssize_t set_temp_crit_hyst(struct device dev, struct device_attribute attr, const char *buf, size_t count)
1da177e4 LT	167	{
	168	struct i2c_client *client = to_i2c_client(dev);
	169	struct lm77_data *data = i2c_get_clientdata(client);
	170	unsigned long val = simple_strtoul(buf, NULL, 10);
	171
9a61bf63	172	mutex_lock(&data->update_lock);
1da177e4 LT	173	data->temp_hyst = data->temp_crit - val;
	174	lm77_write_value(client, LM77_REG_TEMP_HYST,
	175	LM77_TEMP_TO_REG(data->temp_hyst));
9a61bf63	176	mutex_unlock(&data->update_lock);
1da177e4 LT	177	return count;
	178	}
	179
	180	/* preserve hysteresis when setting T_crit */
8627f9ba	181	static ssize_t set_temp_crit(struct device dev, struct device_attribute attr, const char *buf, size_t count)
1da177e4 LT	182	{
	183	struct i2c_client *client = to_i2c_client(dev);
	184	struct lm77_data *data = i2c_get_clientdata(client);
	185	long val = simple_strtoul(buf, NULL, 10);
	186	int oldcrithyst;
	187
9a61bf63	188	mutex_lock(&data->update_lock);
1da177e4 LT	189	oldcrithyst = data->temp_crit - data->temp_hyst;
	190	data->temp_crit = val;
	191	data->temp_hyst = data->temp_crit - oldcrithyst;
	192	lm77_write_value(client, LM77_REG_TEMP_CRIT,
	193	LM77_TEMP_TO_REG(data->temp_crit));
	194	lm77_write_value(client, LM77_REG_TEMP_HYST,
	195	LM77_TEMP_TO_REG(data->temp_hyst));
9a61bf63	196	mutex_unlock(&data->update_lock);
1da177e4 LT	197	return count;
	198	}
	199
1f52af0f JD	200	static ssize_t show_alarm(struct device dev, struct device_attribute attr,
	201	char *buf)
	202	{
	203	int bitnr = to_sensor_dev_attr(attr)->index;
	204	struct lm77_data *data = lm77_update_device(dev);
	205	return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1);
	206	}
	207
1da177e4 LT	208	static DEVICE_ATTR(temp1_input, S_IRUGO,
	209	show_temp_input, NULL);
	210	static DEVICE_ATTR(temp1_crit, S_IWUSR \| S_IRUGO,
	211	show_temp_crit, set_temp_crit);
	212	static DEVICE_ATTR(temp1_min, S_IWUSR \| S_IRUGO,
	213	show_temp_min, set_temp_min);
	214	static DEVICE_ATTR(temp1_max, S_IWUSR \| S_IRUGO,
	215	show_temp_max, set_temp_max);
	216
	217	static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR \| S_IRUGO,
	218	show_temp_crit_hyst, set_temp_crit_hyst);
	219	static DEVICE_ATTR(temp1_min_hyst, S_IRUGO,
	220	show_temp_min_hyst, NULL);
	221	static DEVICE_ATTR(temp1_max_hyst, S_IRUGO,
	222	show_temp_max_hyst, NULL);
	223
1f52af0f JD	224	static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
	225	static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
	226	static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);
1da177e4	227
0501a381 MH	228	static struct attribute *lm77_attributes[] = {
	229	&dev_attr_temp1_input.attr,
	230	&dev_attr_temp1_crit.attr,
	231	&dev_attr_temp1_min.attr,
	232	&dev_attr_temp1_max.attr,
	233	&dev_attr_temp1_crit_hyst.attr,
	234	&dev_attr_temp1_min_hyst.attr,
	235	&dev_attr_temp1_max_hyst.attr,
1f52af0f JD	236	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
	237	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
	238	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
0501a381 MH	239	NULL
	240	};
	241
	242	static const struct attribute_group lm77_group = {
	243	.attrs = lm77_attributes,
	244	};
	245
a189dd62	246	/* Return 0 if detection is successful, -ENODEV otherwise */
310ec792	247	static int lm77_detect(struct i2c_client *new_client,
a189dd62	248	struct i2c_board_info *info)
1da177e4	249	{
a189dd62	250	struct i2c_adapter *adapter = new_client->adapter;
747d9bed	251	int i, cur, conf, hyst, crit, min, max;
1da177e4 LT	252
	253	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA \|
	254	I2C_FUNC_SMBUS_WORD_DATA))
a189dd62	255	return -ENODEV;
1da177e4 LT	256
	257	/* Here comes the remaining detection. Since the LM77 has no
	258	register dedicated to identification, we have to rely on the
	259	following tricks:
	260
	261	1. the high 4 bits represent the sign and thus they should
	262	always be the same
	263	2. the high 3 bits are unused in the configuration register
	264	3. addresses 0x06 and 0x07 return the last read value
	265	4. registers cycling over 8-address boundaries
	266
	267	Word-sized registers are high-byte first. */
1da177e4	268
747d9bed JD	269	/* addresses cycling */
	270	cur = i2c_smbus_read_word_data(new_client, 0);
	271	conf = i2c_smbus_read_byte_data(new_client, 1);
	272	hyst = i2c_smbus_read_word_data(new_client, 2);
	273	crit = i2c_smbus_read_word_data(new_client, 3);
	274	min = i2c_smbus_read_word_data(new_client, 4);
	275	max = i2c_smbus_read_word_data(new_client, 5);
	276	for (i = 8; i <= 0xff; i += 8) {
	277	if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
	278	\|\| i2c_smbus_read_word_data(new_client, i + 2) != hyst
	279	\|\| i2c_smbus_read_word_data(new_client, i + 3) != crit
	280	\|\| i2c_smbus_read_word_data(new_client, i + 4) != min
	281	\|\| i2c_smbus_read_word_data(new_client, i + 5) != max)
a189dd62	282	return -ENODEV;
747d9bed	283	}
1da177e4	284
747d9bed JD	285	/* sign bits */
	286	if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0)
	287	\|\| ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0)
	288	\|\| ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0)
	289	\|\| ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0)
	290	\|\| ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0))
	291	return -ENODEV;
1da177e4	292
747d9bed JD	293	/* unused bits */
	294	if (conf & 0xe0)
	295	return -ENODEV;
	296
	297	/* 0x06 and 0x07 return the last read value */
	298	cur = i2c_smbus_read_word_data(new_client, 0);
	299	if (i2c_smbus_read_word_data(new_client, 6) != cur
	300	\|\| i2c_smbus_read_word_data(new_client, 7) != cur)
	301	return -ENODEV;
	302	hyst = i2c_smbus_read_word_data(new_client, 2);
	303	if (i2c_smbus_read_word_data(new_client, 6) != hyst
	304	\|\| i2c_smbus_read_word_data(new_client, 7) != hyst)
	305	return -ENODEV;
	306	min = i2c_smbus_read_word_data(new_client, 4);
	307	if (i2c_smbus_read_word_data(new_client, 6) != min
	308	\|\| i2c_smbus_read_word_data(new_client, 7) != min)
	309	return -ENODEV;
1da177e4	310
a189dd62	311	strlcpy(info->type, "lm77", I2C_NAME_SIZE);
1da177e4	312
a189dd62 JD	313	return 0;
	314	}
	315
	316	static int lm77_probe(struct i2c_client *new_client,
	317	const struct i2c_device_id *id)
	318	{
	319	struct lm77_data *data;
	320	int err;
	321
	322	data = kzalloc(sizeof(struct lm77_data), GFP_KERNEL);
	323	if (!data) {
	324	err = -ENOMEM;
	325	goto exit;
1da177e4 LT	326	}
1da177e4 LT	327
a189dd62	328	i2c_set_clientdata(new_client, data);
1da177e4	329	data->valid = 0;
9a61bf63	330	mutex_init(&data->update_lock);
1da177e4	331
1da177e4 LT	332	/* Initialize the LM77 chip */
	333	lm77_init_client(new_client);
	334
	335	/* Register sysfs hooks */
0501a381	336	if ((err = sysfs_create_group(&new_client->dev.kobj, &lm77_group)))
a189dd62	337	goto exit_free;
0501a381	338
1beeffe4 TJ	339	data->hwmon_dev = hwmon_device_register(&new_client->dev);
	340	if (IS_ERR(data->hwmon_dev)) {
	341	err = PTR_ERR(data->hwmon_dev);
0501a381	342	goto exit_remove;
943b0830 MH	343	}
943b0830 MH	344
1da177e4 LT	345	return 0;
1da177e4 LT	346
0501a381 MH	347	exit_remove:
0501a381 MH	348	sysfs_remove_group(&new_client->dev.kobj, &lm77_group);
1da177e4 LT	349	exit_free:
	350	kfree(data);
	351	exit:
	352	return err;
	353	}
	354
a189dd62	355	static int lm77_remove(struct i2c_client *client)
1da177e4	356	{
943b0830	357	struct lm77_data *data = i2c_get_clientdata(client);
1beeffe4	358	hwmon_device_unregister(data->hwmon_dev);
0501a381	359	sysfs_remove_group(&client->dev.kobj, &lm77_group);
943b0830	360	kfree(data);
1da177e4 LT	361	return 0;
	362	}
	363
	364	/* All registers are word-sized, except for the configuration register.
	365	The LM77 uses the high-byte first convention. */
	366	static u16 lm77_read_value(struct i2c_client *client, u8 reg)
	367	{
	368	if (reg == LM77_REG_CONF)
	369	return i2c_smbus_read_byte_data(client, reg);
	370	else
	371	return swab16(i2c_smbus_read_word_data(client, reg));
	372	}
	373
	374	static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value)
	375	{
	376	if (reg == LM77_REG_CONF)
	377	return i2c_smbus_write_byte_data(client, reg, value);
	378	else
	379	return i2c_smbus_write_word_data(client, reg, swab16(value));
	380	}
	381
	382	static void lm77_init_client(struct i2c_client *client)
	383	{
	384	/* Initialize the LM77 chip - turn off shutdown mode */
	385	int conf = lm77_read_value(client, LM77_REG_CONF);
	386	if (conf & 1)
	387	lm77_write_value(client, LM77_REG_CONF, conf & 0xfe);
	388	}
	389
	390	static struct lm77_data lm77_update_device(struct device dev)
	391	{
	392	struct i2c_client *client = to_i2c_client(dev);
	393	struct lm77_data *data = i2c_get_clientdata(client);
	394
9a61bf63	395	mutex_lock(&data->update_lock);
1da177e4 LT	396
	397	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
	398	\|\| !data->valid) {
	399	dev_dbg(&client->dev, "Starting lm77 update\n");
	400	data->temp_input =
	401	LM77_TEMP_FROM_REG(lm77_read_value(client,
	402	LM77_REG_TEMP));
	403	data->temp_hyst =
	404	LM77_TEMP_FROM_REG(lm77_read_value(client,
	405	LM77_REG_TEMP_HYST));
	406	data->temp_crit =
	407	LM77_TEMP_FROM_REG(lm77_read_value(client,
	408	LM77_REG_TEMP_CRIT));
	409	data->temp_min =
	410	LM77_TEMP_FROM_REG(lm77_read_value(client,
	411	LM77_REG_TEMP_MIN));
	412	data->temp_max =
	413	LM77_TEMP_FROM_REG(lm77_read_value(client,
	414	LM77_REG_TEMP_MAX));
	415	data->alarms =
	416	lm77_read_value(client, LM77_REG_TEMP) & 0x0007;
	417	data->last_updated = jiffies;
	418	data->valid = 1;
	419	}
	420
9a61bf63	421	mutex_unlock(&data->update_lock);
1da177e4 LT	422
	423	return data;
	424	}
	425
	426	static int __init sensors_lm77_init(void)
	427	{
	428	return i2c_add_driver(&lm77_driver);
	429	}
	430
	431	static void __exit sensors_lm77_exit(void)
	432	{
	433	i2c_del_driver(&lm77_driver);
	434	}
	435
	436	MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>");
	437	MODULE_DESCRIPTION("LM77 driver");
	438	MODULE_LICENSE("GPL");
	439
	440	module_init(sensors_lm77_init);
	441	module_exit(sensors_lm77_exit);