[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 };

/* 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", 0 },
	{ }
};
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 = clamp_val(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;							\
	int err = kstrtol(buf, 10, &val);				\
	if (err)							\
		return err;						\
									\
	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;
	int err;

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

	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);
	int oldcrithyst;
	unsigned long val;
	int err;

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

	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 *client, struct i2c_board_info *info)
{
	struct i2c_adapter *adapter = 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(client, 0);
	conf = i2c_smbus_read_byte_data(client, 1);
	hyst = i2c_smbus_read_word_data(client, 2);
	crit = i2c_smbus_read_word_data(client, 3);
	min = i2c_smbus_read_word_data(client, 4);
	max = i2c_smbus_read_word_data(client, 5);
	for (i = 8; i <= 0xff; i += 8) {
		if (i2c_smbus_read_byte_data(client, i + 1) != conf
		 || i2c_smbus_read_word_data(client, i + 2) != hyst
		 || i2c_smbus_read_word_data(client, i + 3) != crit
		 || i2c_smbus_read_word_data(client, i + 4) != min
		 || i2c_smbus_read_word_data(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(client, 0);
	if (i2c_smbus_read_word_data(client, 6) != cur
	 || i2c_smbus_read_word_data(client, 7) != cur)
		return -ENODEV;
	hyst = i2c_smbus_read_word_data(client, 2);
	if (i2c_smbus_read_word_data(client, 6) != hyst
	 || i2c_smbus_read_word_data(client, 7) != hyst)
		return -ENODEV;
	min = i2c_smbus_read_word_data(client, 4);
	if (i2c_smbus_read_word_data(client, 6) != min
	 || i2c_smbus_read_word_data(client, 7) != min)
		return -ENODEV;

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

	return 0;
}

static int lm77_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
	struct device *dev = &client->dev;
	struct lm77_data *data;
	int err;

	data = devm_kzalloc(dev, sizeof(struct lm77_data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

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

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

	/* Register sysfs hooks */
	err = sysfs_create_group(&dev->kobj, &lm77_group);
	if (err)
		return err;

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

	return 0;

exit_remove:
	sysfs_remove_group(&dev->kobj, &lm77_group);
	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);
	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 i2c_smbus_read_word_swapped(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_swapped(client, reg, 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;
}

module_i2c_driver(lm77_driver);

MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>");
MODULE_DESCRIPTION("LM77 driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4	1	/*
02fe2fd9 GR	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	*/
1da177e4	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	41
1da177e4 LT	42	/* The LM77 registers */
	43	#define LM77_REG_TEMP 0x00
	44	#define LM77_REG_CONF 0x01
	45	#define LM77_REG_TEMP_HYST 0x02
	46	#define LM77_REG_TEMP_CRIT 0x03
	47	#define LM77_REG_TEMP_MIN 0x04
	48	#define LM77_REG_TEMP_MAX 0x05
	49
	50	/* Each client has this additional data */
	51	struct lm77_data {
02fe2fd9	52	struct device *hwmon_dev;
9a61bf63	53	struct mutex update_lock;
1da177e4 LT	54	char valid;
	55	unsigned long last_updated; /* In jiffies */
	56	int temp_input; /* Temperatures */
	57	int temp_crit;
	58	int temp_min;
	59	int temp_max;
	60	int temp_hyst;
	61	u8 alarms;
	62	};
	63
a189dd62 JD	64	static int lm77_probe(struct i2c_client *client,
a189dd62 JD	65	const struct i2c_device_id *id);
310ec792	66	static int lm77_detect(struct i2c_client client, struct i2c_board_info info);
1da177e4	67	static void lm77_init_client(struct i2c_client *client);
a189dd62	68	static int lm77_remove(struct i2c_client *client);
1da177e4 LT	69	static u16 lm77_read_value(struct i2c_client *client, u8 reg);
	70	static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value);
	71
	72	static struct lm77_data lm77_update_device(struct device dev);
	73
	74
a189dd62	75	static const struct i2c_device_id lm77_id[] = {
1f86df49	76	{ "lm77", 0 },
a189dd62 JD	77	{ }
	78	};
	79	MODULE_DEVICE_TABLE(i2c, lm77_id);
	80
1da177e4 LT	81	/* This is the driver that will be inserted */
1da177e4 LT	82	static struct i2c_driver lm77_driver = {
a189dd62	83	.class = I2C_CLASS_HWMON,
cdaf7934	84	.driver = {
cdaf7934 LR	85	.name = "lm77",
cdaf7934 LR	86	},
a189dd62 JD	87	.probe = lm77_probe,
	88	.remove = lm77_remove,
	89	.id_table = lm77_id,
	90	.detect = lm77_detect,
c3813d6a	91	.address_list = normal_i2c,
1da177e4 LT	92	};
	93
	94	/* straight from the datasheet */
	95	#define LM77_TEMP_MIN (-55000)
	96	#define LM77_TEMP_MAX 125000
	97
02fe2fd9 GR	98	/*
	99	* In the temperature registers, the low 3 bits are not part of the
	100	* temperature values; they are the status bits.
	101	*/
413b6451	102	static inline s16 LM77_TEMP_TO_REG(int temp)
1da177e4	103	{
2a844c14	104	int ntemp = clamp_val(temp, LM77_TEMP_MIN, LM77_TEMP_MAX);
413b6451	105	return (ntemp / 500) * 8;
1da177e4 LT	106	}
1da177e4 LT	107
413b6451	108	static inline int LM77_TEMP_FROM_REG(s16 reg)
1da177e4	109	{
413b6451	110	return (reg / 8) * 500;
1da177e4 LT	111	}
	112
	113	/* sysfs stuff */
	114
	115	/* read routines for temperature limits */
	116	#define show(value) \
02fe2fd9 GR	117	static ssize_t show_##value(struct device *dev, \
	118	struct device_attribute *attr, \
	119	char *buf) \
1da177e4 LT	120	{ \
	121	struct lm77_data *data = lm77_update_device(dev); \
	122	return sprintf(buf, "%d\n", data->value); \
	123	}
	124
	125	show(temp_input);
	126	show(temp_crit);
	127	show(temp_min);
	128	show(temp_max);
1da177e4 LT	129
1da177e4 LT	130	/* read routines for hysteresis values */
02fe2fd9 GR	131	static ssize_t show_temp_crit_hyst(struct device *dev,
02fe2fd9 GR	132	struct device_attribute attr, char buf)
1da177e4 LT	133	{
	134	struct lm77_data *data = lm77_update_device(dev);
	135	return sprintf(buf, "%d\n", data->temp_crit - data->temp_hyst);
	136	}
02fe2fd9 GR	137	static ssize_t show_temp_min_hyst(struct device *dev,
02fe2fd9 GR	138	struct device_attribute attr, char buf)
1da177e4 LT	139	{
	140	struct lm77_data *data = lm77_update_device(dev);
	141	return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst);
	142	}
02fe2fd9 GR	143	static ssize_t show_temp_max_hyst(struct device *dev,
02fe2fd9 GR	144	struct device_attribute attr, char buf)
1da177e4 LT	145	{
	146	struct lm77_data *data = lm77_update_device(dev);
	147	return sprintf(buf, "%d\n", data->temp_max - data->temp_hyst);
	148	}
	149
	150	/* write routines */
	151	#define set(value, reg) \
02fe2fd9 GR	152	static ssize_t set_##value(struct device dev, struct device_attribute attr, \
	153	const char *buf, size_t count) \
	154	{ \
	155	struct i2c_client *client = to_i2c_client(dev); \
	156	struct lm77_data *data = i2c_get_clientdata(client); \
	157	long val; \
	158	int err = kstrtol(buf, 10, &val); \
	159	if (err) \
	160	return err; \
	161	\
	162	mutex_lock(&data->update_lock); \
	163	data->value = val; \
	164	lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value)); \
	165	mutex_unlock(&data->update_lock); \
	166	return count; \
1da177e4 LT	167	}
	168
	169	set(temp_min, LM77_REG_TEMP_MIN);
	170	set(temp_max, LM77_REG_TEMP_MAX);
	171
02fe2fd9 GR	172	/*
	173	* hysteresis is stored as a relative value on the chip, so it has to be
	174	* converted first
	175	*/
	176	static ssize_t set_temp_crit_hyst(struct device *dev,
	177	struct device_attribute *attr,
	178	const char *buf, size_t count)
1da177e4 LT	179	{
	180	struct i2c_client *client = to_i2c_client(dev);
	181	struct lm77_data *data = i2c_get_clientdata(client);
02fe2fd9 GR	182	unsigned long val;
	183	int err;
	184
	185	err = kstrtoul(buf, 10, &val);
	186	if (err)
	187	return err;
1da177e4	188
9a61bf63	189	mutex_lock(&data->update_lock);
1da177e4 LT	190	data->temp_hyst = data->temp_crit - val;
	191	lm77_write_value(client, LM77_REG_TEMP_HYST,
	192	LM77_TEMP_TO_REG(data->temp_hyst));
9a61bf63	193	mutex_unlock(&data->update_lock);
1da177e4 LT	194	return count;
	195	}
	196
	197	/* preserve hysteresis when setting T_crit */
02fe2fd9 GR	198	static ssize_t set_temp_crit(struct device dev, struct device_attribute attr,
02fe2fd9 GR	199	const char *buf, size_t count)
1da177e4 LT	200	{
	201	struct i2c_client *client = to_i2c_client(dev);
	202	struct lm77_data *data = i2c_get_clientdata(client);
1da177e4	203	int oldcrithyst;
02fe2fd9 GR	204	unsigned long val;
	205	int err;
	206
	207	err = kstrtoul(buf, 10, &val);
	208	if (err)
	209	return err;
	210
9a61bf63	211	mutex_lock(&data->update_lock);
1da177e4 LT	212	oldcrithyst = data->temp_crit - data->temp_hyst;
	213	data->temp_crit = val;
	214	data->temp_hyst = data->temp_crit - oldcrithyst;
	215	lm77_write_value(client, LM77_REG_TEMP_CRIT,
	216	LM77_TEMP_TO_REG(data->temp_crit));
	217	lm77_write_value(client, LM77_REG_TEMP_HYST,
	218	LM77_TEMP_TO_REG(data->temp_hyst));
9a61bf63	219	mutex_unlock(&data->update_lock);
1da177e4 LT	220	return count;
	221	}
	222
1f52af0f JD	223	static ssize_t show_alarm(struct device dev, struct device_attribute attr,
	224	char *buf)
	225	{
	226	int bitnr = to_sensor_dev_attr(attr)->index;
	227	struct lm77_data *data = lm77_update_device(dev);
	228	return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1);
	229	}
	230
1da177e4 LT	231	static DEVICE_ATTR(temp1_input, S_IRUGO,
	232	show_temp_input, NULL);
	233	static DEVICE_ATTR(temp1_crit, S_IWUSR \| S_IRUGO,
	234	show_temp_crit, set_temp_crit);
	235	static DEVICE_ATTR(temp1_min, S_IWUSR \| S_IRUGO,
	236	show_temp_min, set_temp_min);
	237	static DEVICE_ATTR(temp1_max, S_IWUSR \| S_IRUGO,
	238	show_temp_max, set_temp_max);
	239
	240	static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR \| S_IRUGO,
	241	show_temp_crit_hyst, set_temp_crit_hyst);
	242	static DEVICE_ATTR(temp1_min_hyst, S_IRUGO,
	243	show_temp_min_hyst, NULL);
	244	static DEVICE_ATTR(temp1_max_hyst, S_IRUGO,
	245	show_temp_max_hyst, NULL);
	246
1f52af0f JD	247	static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
	248	static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
	249	static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);
1da177e4	250
0501a381 MH	251	static struct attribute *lm77_attributes[] = {
	252	&dev_attr_temp1_input.attr,
	253	&dev_attr_temp1_crit.attr,
	254	&dev_attr_temp1_min.attr,
	255	&dev_attr_temp1_max.attr,
	256	&dev_attr_temp1_crit_hyst.attr,
	257	&dev_attr_temp1_min_hyst.attr,
	258	&dev_attr_temp1_max_hyst.attr,
1f52af0f JD	259	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
	260	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
	261	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
0501a381 MH	262	NULL
	263	};
	264
	265	static const struct attribute_group lm77_group = {
	266	.attrs = lm77_attributes,
	267	};
	268
a189dd62	269	/* Return 0 if detection is successful, -ENODEV otherwise */
efd2d117	270	static int lm77_detect(struct i2c_client client, struct i2c_board_info info)
1da177e4	271	{
efd2d117	272	struct i2c_adapter *adapter = client->adapter;
747d9bed	273	int i, cur, conf, hyst, crit, min, max;
1da177e4 LT	274
	275	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA \|
	276	I2C_FUNC_SMBUS_WORD_DATA))
a189dd62	277	return -ENODEV;
1da177e4	278
02fe2fd9 GR	279	/*
	280	* Here comes the remaining detection. Since the LM77 has no
	281	* register dedicated to identification, we have to rely on the
	282	* following tricks:
	283	*
	284	* 1. the high 4 bits represent the sign and thus they should
	285	* always be the same
	286	* 2. the high 3 bits are unused in the configuration register
	287	* 3. addresses 0x06 and 0x07 return the last read value
	288	* 4. registers cycling over 8-address boundaries
	289	*
	290	* Word-sized registers are high-byte first.
	291	*/
1da177e4	292
747d9bed	293	/* addresses cycling */
efd2d117 GR	294	cur = i2c_smbus_read_word_data(client, 0);
	295	conf = i2c_smbus_read_byte_data(client, 1);
	296	hyst = i2c_smbus_read_word_data(client, 2);
	297	crit = i2c_smbus_read_word_data(client, 3);
	298	min = i2c_smbus_read_word_data(client, 4);
	299	max = i2c_smbus_read_word_data(client, 5);
747d9bed	300	for (i = 8; i <= 0xff; i += 8) {
efd2d117 GR	301	if (i2c_smbus_read_byte_data(client, i + 1) != conf
	302	\|\| i2c_smbus_read_word_data(client, i + 2) != hyst
	303	\|\| i2c_smbus_read_word_data(client, i + 3) != crit
	304	\|\| i2c_smbus_read_word_data(client, i + 4) != min
	305	\|\| i2c_smbus_read_word_data(client, i + 5) != max)
a189dd62	306	return -ENODEV;
747d9bed	307	}
1da177e4	308
747d9bed JD	309	/* sign bits */
	310	if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0)
	311	\|\| ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0)
	312	\|\| ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0)
	313	\|\| ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0)
	314	\|\| ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0))
	315	return -ENODEV;
1da177e4	316
747d9bed JD	317	/* unused bits */
	318	if (conf & 0xe0)
	319	return -ENODEV;
	320
	321	/* 0x06 and 0x07 return the last read value */
efd2d117 GR	322	cur = i2c_smbus_read_word_data(client, 0);
	323	if (i2c_smbus_read_word_data(client, 6) != cur
	324	\|\| i2c_smbus_read_word_data(client, 7) != cur)
747d9bed	325	return -ENODEV;
efd2d117 GR	326	hyst = i2c_smbus_read_word_data(client, 2);
	327	if (i2c_smbus_read_word_data(client, 6) != hyst
	328	\|\| i2c_smbus_read_word_data(client, 7) != hyst)
747d9bed	329	return -ENODEV;
efd2d117 GR	330	min = i2c_smbus_read_word_data(client, 4);
	331	if (i2c_smbus_read_word_data(client, 6) != min
	332	\|\| i2c_smbus_read_word_data(client, 7) != min)
747d9bed	333	return -ENODEV;
1da177e4	334
a189dd62	335	strlcpy(info->type, "lm77", I2C_NAME_SIZE);
1da177e4	336
a189dd62 JD	337	return 0;
	338	}
	339
efd2d117	340	static int lm77_probe(struct i2c_client client, const struct i2c_device_id id)
a189dd62	341	{
efd2d117	342	struct device *dev = &client->dev;
a189dd62 JD	343	struct lm77_data *data;
	344	int err;
	345
52714c04 GR	346	data = devm_kzalloc(dev, sizeof(struct lm77_data), GFP_KERNEL);
	347	if (!data)
	348	return -ENOMEM;
1da177e4	349
efd2d117	350	i2c_set_clientdata(client, data);
1da177e4	351	data->valid = 0;
9a61bf63	352	mutex_init(&data->update_lock);
1da177e4	353
1da177e4	354	/* Initialize the LM77 chip */
efd2d117	355	lm77_init_client(client);
1da177e4 LT	356
1da177e4 LT	357	/* Register sysfs hooks */
efd2d117	358	err = sysfs_create_group(&dev->kobj, &lm77_group);
02fe2fd9	359	if (err)
52714c04	360	return err;
0501a381	361
efd2d117	362	data->hwmon_dev = hwmon_device_register(dev);
1beeffe4 TJ	363	if (IS_ERR(data->hwmon_dev)) {
1beeffe4 TJ	364	err = PTR_ERR(data->hwmon_dev);
0501a381	365	goto exit_remove;
943b0830 MH	366	}
943b0830 MH	367
1da177e4 LT	368	return 0;
1da177e4 LT	369
0501a381	370	exit_remove:
efd2d117	371	sysfs_remove_group(&dev->kobj, &lm77_group);
1da177e4 LT	372	return err;
	373	}
	374
a189dd62	375	static int lm77_remove(struct i2c_client *client)
1da177e4	376	{
943b0830	377	struct lm77_data *data = i2c_get_clientdata(client);
1beeffe4	378	hwmon_device_unregister(data->hwmon_dev);
0501a381	379	sysfs_remove_group(&client->dev.kobj, &lm77_group);
1da177e4 LT	380	return 0;
	381	}
	382
02fe2fd9 GR	383	/*
	384	* All registers are word-sized, except for the configuration register.
	385	* The LM77 uses the high-byte first convention.
	386	*/
1da177e4 LT	387	static u16 lm77_read_value(struct i2c_client *client, u8 reg)
	388	{
	389	if (reg == LM77_REG_CONF)
	390	return i2c_smbus_read_byte_data(client, reg);
	391	else
90f4102c	392	return i2c_smbus_read_word_swapped(client, reg);
1da177e4 LT	393	}
	394
	395	static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value)
	396	{
	397	if (reg == LM77_REG_CONF)
	398	return i2c_smbus_write_byte_data(client, reg, value);
	399	else
90f4102c	400	return i2c_smbus_write_word_swapped(client, reg, value);
1da177e4 LT	401	}
	402
	403	static void lm77_init_client(struct i2c_client *client)
	404	{
	405	/* Initialize the LM77 chip - turn off shutdown mode */
	406	int conf = lm77_read_value(client, LM77_REG_CONF);
	407	if (conf & 1)
	408	lm77_write_value(client, LM77_REG_CONF, conf & 0xfe);
	409	}
	410
	411	static struct lm77_data lm77_update_device(struct device dev)
	412	{
	413	struct i2c_client *client = to_i2c_client(dev);
	414	struct lm77_data *data = i2c_get_clientdata(client);
	415
9a61bf63	416	mutex_lock(&data->update_lock);
1da177e4 LT	417
	418	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
	419	\|\| !data->valid) {
	420	dev_dbg(&client->dev, "Starting lm77 update\n");
	421	data->temp_input =
	422	LM77_TEMP_FROM_REG(lm77_read_value(client,
	423	LM77_REG_TEMP));
	424	data->temp_hyst =
	425	LM77_TEMP_FROM_REG(lm77_read_value(client,
	426	LM77_REG_TEMP_HYST));
	427	data->temp_crit =
	428	LM77_TEMP_FROM_REG(lm77_read_value(client,
	429	LM77_REG_TEMP_CRIT));
	430	data->temp_min =
	431	LM77_TEMP_FROM_REG(lm77_read_value(client,
	432	LM77_REG_TEMP_MIN));
	433	data->temp_max =
	434	LM77_TEMP_FROM_REG(lm77_read_value(client,
	435	LM77_REG_TEMP_MAX));
	436	data->alarms =
	437	lm77_read_value(client, LM77_REG_TEMP) & 0x0007;
	438	data->last_updated = jiffies;
	439	data->valid = 1;
	440	}
	441
9a61bf63	442	mutex_unlock(&data->update_lock);
1da177e4 LT	443
	444	return data;
	445	}
	446
f0967eea	447	module_i2c_driver(lm77_driver);
1da177e4 LT	448
	449	MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>");
	450	MODULE_DESCRIPTION("LM77 driver");
	451	MODULE_LICENSE("GPL");