[mirror_ubuntu-bionic-kernel.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.
 */

#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

enum temp_index {
	t_input = 0,
	t_crit,
	t_min,
	t_max,
	t_hyst,
	t_num_temp
};

static const u8 temp_regs[t_num_temp] = {
	[t_input] = LM77_REG_TEMP,
	[t_min] = LM77_REG_TEMP_MIN,
	[t_max] = LM77_REG_TEMP_MAX,
	[t_crit] = LM77_REG_TEMP_CRIT,
	[t_hyst] = LM77_REG_TEMP_HYST,
};

/* Each client has this additional data */
struct lm77_data {
	struct i2c_client	*client;
	struct mutex		update_lock;
	char			valid;
	unsigned long		last_updated;	/* In jiffies */
	int			temp[t_num_temp]; /* index using temp_index */
	u8			alarms;
};

/* 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)
{
	return (temp / 500) * 8;
}

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

/*
 * 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 struct lm77_data *lm77_update_device(struct device *dev)
{
	struct lm77_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	int i;

	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");
		for (i = 0; i < t_num_temp; i++) {
			data->temp[i] =
			  LM77_TEMP_FROM_REG(lm77_read_value(client,
							     temp_regs[i]));
		}
		data->alarms =
			lm77_read_value(client, LM77_REG_TEMP) & 0x0007;
		data->last_updated = jiffies;
		data->valid = 1;
	}

	mutex_unlock(&data->update_lock);

	return data;
}

/* sysfs stuff */

static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
			 char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct lm77_data *data = lm77_update_device(dev);

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

static ssize_t show_temp_hyst(struct device *dev,
			      struct device_attribute *devattr, char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct lm77_data *data = lm77_update_device(dev);
	int nr = attr->index;
	int temp;

	temp = nr == t_min ? data->temp[nr] + data->temp[t_hyst] :
			     data->temp[nr] - data->temp[t_hyst];

	return sprintf(buf, "%d\n", temp);
}

static ssize_t set_temp(struct device *dev, struct device_attribute *devattr,
			const char *buf, size_t count)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct lm77_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	int nr = attr->index;
	long val;
	int err;

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

	val = clamp_val(val, LM77_TEMP_MIN, LM77_TEMP_MAX);
	mutex_lock(&data->update_lock);
	data->temp[nr] = val;
	lm77_write_value(client, temp_regs[nr], LM77_TEMP_TO_REG(val));
	mutex_unlock(&data->update_lock);
	return count;
}

/*
 * hysteresis is stored as a relative value on the chip, so it has to be
 * converted first.
 */
static ssize_t set_temp_hyst(struct device *dev,
			     struct device_attribute *devattr,
			     const char *buf, size_t count)
{
	struct lm77_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	long val;
	int err;

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

	mutex_lock(&data->update_lock);
	val = clamp_val(data->temp[t_crit] - val, LM77_TEMP_MIN, LM77_TEMP_MAX);
	data->temp[t_hyst] = val;
	lm77_write_value(client, LM77_REG_TEMP_HYST,
			 LM77_TEMP_TO_REG(data->temp[t_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 SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, t_input);
static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp, set_temp,
			  t_crit);
static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp,
			  t_min);
static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp,
			  t_max);

static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp_hyst,
			  set_temp_hyst, t_crit);
static SENSOR_DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp_hyst, NULL, t_min);
static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp_hyst, NULL, t_max);

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_attrs[] = {
	&sensor_dev_attr_temp1_input.dev_attr.attr,
	&sensor_dev_attr_temp1_crit.dev_attr.attr,
	&sensor_dev_attr_temp1_min.dev_attr.attr,
	&sensor_dev_attr_temp1_max.dev_attr.attr,
	&sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
	&sensor_dev_attr_temp1_min_hyst.dev_attr.attr,
	&sensor_dev_attr_temp1_max_hyst.dev_attr.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
};
ATTRIBUTE_GROUPS(lm77);

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

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

	data->client = client;
	mutex_init(&data->update_lock);

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

	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
							   data, lm77_groups);
	return PTR_ERR_OR_ZERO(hwmon_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,
	.id_table	= lm77_id,
	.detect		= lm77_detect,
	.address_list	= normal_i2c,
};

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.
02fe2fd9	22	*/
1da177e4	23
1da177e4 LT	24	#include <linux/module.h>
	25	#include <linux/init.h>
	26	#include <linux/slab.h>
	27	#include <linux/jiffies.h>
	28	#include <linux/i2c.h>
943b0830	29	#include <linux/hwmon.h>
1f52af0f	30	#include <linux/hwmon-sysfs.h>
943b0830	31	#include <linux/err.h>
9a61bf63	32	#include <linux/mutex.h>
1da177e4 LT	33
1da177e4 LT	34	/* Addresses to scan */
25e9c86d MH	35	static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
25e9c86d MH	36	I2C_CLIENT_END };
1da177e4	37
1da177e4 LT	38	/* The LM77 registers */
	39	#define LM77_REG_TEMP 0x00
	40	#define LM77_REG_CONF 0x01
	41	#define LM77_REG_TEMP_HYST 0x02
	42	#define LM77_REG_TEMP_CRIT 0x03
	43	#define LM77_REG_TEMP_MIN 0x04
	44	#define LM77_REG_TEMP_MAX 0x05
	45
48dbd6ff GR	46	enum temp_index {
	47	t_input = 0,
	48	t_crit,
	49	t_min,
	50	t_max,
	51	t_hyst,
	52	t_num_temp
	53	};
	54
	55	static const u8 temp_regs[t_num_temp] = {
	56	[t_input] = LM77_REG_TEMP,
	57	[t_min] = LM77_REG_TEMP_MIN,
	58	[t_max] = LM77_REG_TEMP_MAX,
	59	[t_crit] = LM77_REG_TEMP_CRIT,
	60	[t_hyst] = LM77_REG_TEMP_HYST,
	61	};
	62
1da177e4 LT	63	/* Each client has this additional data */
1da177e4 LT	64	struct lm77_data {
5975dfbf	65	struct i2c_client *client;
9a61bf63	66	struct mutex update_lock;
1da177e4 LT	67	char valid;
1da177e4 LT	68	unsigned long last_updated; /* In jiffies */
48dbd6ff	69	int temp[t_num_temp]; /* index using temp_index */
1da177e4 LT	70	u8 alarms;
	71	};
	72
1da177e4 LT	73	/* straight from the datasheet */
	74	#define LM77_TEMP_MIN (-55000)
	75	#define LM77_TEMP_MAX 125000
	76
02fe2fd9 GR	77	/*
	78	* In the temperature registers, the low 3 bits are not part of the
	79	* temperature values; they are the status bits.
	80	*/
413b6451	81	static inline s16 LM77_TEMP_TO_REG(int temp)
1da177e4	82	{
99765db2	83	return (temp / 500) * 8;
1da177e4 LT	84	}
1da177e4 LT	85
413b6451	86	static inline int LM77_TEMP_FROM_REG(s16 reg)
1da177e4	87	{
413b6451	88	return (reg / 8) * 500;
1da177e4 LT	89	}
1da177e4 LT	90
9f9edcd4 GR	91	/*
	92	* All registers are word-sized, except for the configuration register.
	93	* The LM77 uses the high-byte first convention.
	94	*/
	95	static u16 lm77_read_value(struct i2c_client *client, u8 reg)
	96	{
	97	if (reg == LM77_REG_CONF)
	98	return i2c_smbus_read_byte_data(client, reg);
	99	else
	100	return i2c_smbus_read_word_swapped(client, reg);
	101	}
	102
	103	static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value)
	104	{
	105	if (reg == LM77_REG_CONF)
	106	return i2c_smbus_write_byte_data(client, reg, value);
	107	else
	108	return i2c_smbus_write_word_swapped(client, reg, value);
	109	}
	110
	111	static struct lm77_data lm77_update_device(struct device dev)
	112	{
5975dfbf GR	113	struct lm77_data *data = dev_get_drvdata(dev);
5975dfbf GR	114	struct i2c_client *client = data->client;
48dbd6ff	115	int i;
9f9edcd4 GR	116
	117	mutex_lock(&data->update_lock);
	118
	119	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
	120	\|\| !data->valid) {
	121	dev_dbg(&client->dev, "Starting lm77 update\n");
48dbd6ff GR	122	for (i = 0; i < t_num_temp; i++) {
	123	data->temp[i] =
	124	LM77_TEMP_FROM_REG(lm77_read_value(client,
	125	temp_regs[i]));
	126	}
9f9edcd4 GR	127	data->alarms =
	128	lm77_read_value(client, LM77_REG_TEMP) & 0x0007;
	129	data->last_updated = jiffies;
	130	data->valid = 1;
	131	}
	132
	133	mutex_unlock(&data->update_lock);
	134
	135	return data;
	136	}
	137
1da177e4 LT	138	/* sysfs stuff */
1da177e4 LT	139
48dbd6ff GR	140	static ssize_t show_temp(struct device dev, struct device_attribute devattr,
48dbd6ff GR	141	char *buf)
1da177e4	142	{
48dbd6ff	143	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
1da177e4	144	struct lm77_data *data = lm77_update_device(dev);
48dbd6ff GR	145
48dbd6ff GR	146	return sprintf(buf, "%d\n", data->temp[attr->index]);
1da177e4	147	}
48dbd6ff GR	148
	149	static ssize_t show_temp_hyst(struct device *dev,
	150	struct device_attribute devattr, char buf)
1da177e4	151	{
48dbd6ff	152	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
1da177e4	153	struct lm77_data *data = lm77_update_device(dev);
48dbd6ff GR	154	int nr = attr->index;
48dbd6ff GR	155	int temp;
1da177e4	156
48dbd6ff GR	157	temp = nr == t_min ? data->temp[nr] + data->temp[t_hyst] :
48dbd6ff GR	158	data->temp[nr] - data->temp[t_hyst];
1da177e4	159
48dbd6ff GR	160	return sprintf(buf, "%d\n", temp);
48dbd6ff GR	161	}
1da177e4	162
48dbd6ff GR	163	static ssize_t set_temp(struct device dev, struct device_attribute devattr,
48dbd6ff GR	164	const char *buf, size_t count)
1da177e4	165	{
48dbd6ff	166	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
5975dfbf GR	167	struct lm77_data *data = dev_get_drvdata(dev);
5975dfbf GR	168	struct i2c_client *client = data->client;
48dbd6ff GR	169	int nr = attr->index;
48dbd6ff GR	170	long val;
02fe2fd9 GR	171	int err;
02fe2fd9 GR	172
48dbd6ff	173	err = kstrtol(buf, 10, &val);
02fe2fd9 GR	174	if (err)
02fe2fd9 GR	175	return err;
1da177e4	176
99765db2	177	val = clamp_val(val, LM77_TEMP_MIN, LM77_TEMP_MAX);
9a61bf63	178	mutex_lock(&data->update_lock);
48dbd6ff GR	179	data->temp[nr] = val;
48dbd6ff GR	180	lm77_write_value(client, temp_regs[nr], LM77_TEMP_TO_REG(val));
9a61bf63	181	mutex_unlock(&data->update_lock);
1da177e4 LT	182	return count;
	183	}
	184
48dbd6ff GR	185	/*
	186	* hysteresis is stored as a relative value on the chip, so it has to be
	187	* converted first.
	188	*/
	189	static ssize_t set_temp_hyst(struct device *dev,
	190	struct device_attribute *devattr,
02fe2fd9	191	const char *buf, size_t count)
1da177e4	192	{
5975dfbf GR	193	struct lm77_data *data = dev_get_drvdata(dev);
5975dfbf GR	194	struct i2c_client *client = data->client;
99765db2	195	long val;
02fe2fd9 GR	196	int err;
02fe2fd9 GR	197
99765db2	198	err = kstrtol(buf, 10, &val);
02fe2fd9 GR	199	if (err)
	200	return err;
	201
9a61bf63	202	mutex_lock(&data->update_lock);
99765db2 AL	203	val = clamp_val(data->temp[t_crit] - val, LM77_TEMP_MIN, LM77_TEMP_MAX);
99765db2 AL	204	data->temp[t_hyst] = val;
48dbd6ff GR	205	lm77_write_value(client, LM77_REG_TEMP_HYST,
48dbd6ff GR	206	LM77_TEMP_TO_REG(data->temp[t_hyst]));
9a61bf63	207	mutex_unlock(&data->update_lock);
1da177e4 LT	208	return count;
	209	}
	210
1f52af0f JD	211	static ssize_t show_alarm(struct device dev, struct device_attribute attr,
	212	char *buf)
	213	{
	214	int bitnr = to_sensor_dev_attr(attr)->index;
	215	struct lm77_data *data = lm77_update_device(dev);
	216	return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1);
	217	}
	218
48dbd6ff GR	219	static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, t_input);
	220	static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR \| S_IRUGO, show_temp, set_temp,
	221	t_crit);
	222	static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR \| S_IRUGO, show_temp, set_temp,
	223	t_min);
	224	static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR \| S_IRUGO, show_temp, set_temp,
	225	t_max);
	226
	227	static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR \| S_IRUGO, show_temp_hyst,
	228	set_temp_hyst, t_crit);
	229	static SENSOR_DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp_hyst, NULL, t_min);
	230	static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp_hyst, NULL, t_max);
1da177e4	231
1f52af0f JD	232	static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
	233	static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
	234	static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);
1da177e4	235
5975dfbf	236	static struct attribute *lm77_attrs[] = {
48dbd6ff GR	237	&sensor_dev_attr_temp1_input.dev_attr.attr,
	238	&sensor_dev_attr_temp1_crit.dev_attr.attr,
	239	&sensor_dev_attr_temp1_min.dev_attr.attr,
	240	&sensor_dev_attr_temp1_max.dev_attr.attr,
	241	&sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
	242	&sensor_dev_attr_temp1_min_hyst.dev_attr.attr,
	243	&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
1f52af0f JD	244	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
	245	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
	246	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
0501a381 MH	247	NULL
0501a381 MH	248	};
5975dfbf	249	ATTRIBUTE_GROUPS(lm77);
0501a381	250
a189dd62	251	/* Return 0 if detection is successful, -ENODEV otherwise */
efd2d117	252	static int lm77_detect(struct i2c_client client, struct i2c_board_info info)
1da177e4	253	{
efd2d117	254	struct i2c_adapter *adapter = client->adapter;
747d9bed	255	int i, cur, conf, hyst, crit, min, max;
1da177e4 LT	256
	257	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA \|
	258	I2C_FUNC_SMBUS_WORD_DATA))
a189dd62	259	return -ENODEV;
1da177e4	260
02fe2fd9 GR	261	/*
	262	* Here comes the remaining detection. Since the LM77 has no
	263	* register dedicated to identification, we have to rely on the
	264	* following tricks:
	265	*
	266	* 1. the high 4 bits represent the sign and thus they should
	267	* always be the same
	268	* 2. the high 3 bits are unused in the configuration register
	269	* 3. addresses 0x06 and 0x07 return the last read value
	270	* 4. registers cycling over 8-address boundaries
	271	*
	272	* Word-sized registers are high-byte first.
	273	*/
1da177e4	274
747d9bed	275	/* addresses cycling */
efd2d117 GR	276	cur = i2c_smbus_read_word_data(client, 0);
	277	conf = i2c_smbus_read_byte_data(client, 1);
	278	hyst = i2c_smbus_read_word_data(client, 2);
	279	crit = i2c_smbus_read_word_data(client, 3);
	280	min = i2c_smbus_read_word_data(client, 4);
	281	max = i2c_smbus_read_word_data(client, 5);
747d9bed	282	for (i = 8; i <= 0xff; i += 8) {
efd2d117 GR	283	if (i2c_smbus_read_byte_data(client, i + 1) != conf
	284	\|\| i2c_smbus_read_word_data(client, i + 2) != hyst
	285	\|\| i2c_smbus_read_word_data(client, i + 3) != crit
	286	\|\| i2c_smbus_read_word_data(client, i + 4) != min
	287	\|\| i2c_smbus_read_word_data(client, i + 5) != max)
a189dd62	288	return -ENODEV;
747d9bed	289	}
1da177e4	290
747d9bed JD	291	/* sign bits */
	292	if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0)
	293	\|\| ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0)
	294	\|\| ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0)
	295	\|\| ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0)
	296	\|\| ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0))
	297	return -ENODEV;
1da177e4	298
747d9bed JD	299	/* unused bits */
	300	if (conf & 0xe0)
	301	return -ENODEV;
	302
	303	/* 0x06 and 0x07 return the last read value */
efd2d117 GR	304	cur = i2c_smbus_read_word_data(client, 0);
	305	if (i2c_smbus_read_word_data(client, 6) != cur
	306	\|\| i2c_smbus_read_word_data(client, 7) != cur)
747d9bed	307	return -ENODEV;
efd2d117 GR	308	hyst = i2c_smbus_read_word_data(client, 2);
	309	if (i2c_smbus_read_word_data(client, 6) != hyst
	310	\|\| i2c_smbus_read_word_data(client, 7) != hyst)
747d9bed	311	return -ENODEV;
efd2d117 GR	312	min = i2c_smbus_read_word_data(client, 4);
	313	if (i2c_smbus_read_word_data(client, 6) != min
	314	\|\| i2c_smbus_read_word_data(client, 7) != min)
747d9bed	315	return -ENODEV;
1da177e4	316
a189dd62	317	strlcpy(info->type, "lm77", I2C_NAME_SIZE);
1da177e4	318
a189dd62 JD	319	return 0;
	320	}
	321
9f9edcd4 GR	322	static void lm77_init_client(struct i2c_client *client)
	323	{
	324	/* Initialize the LM77 chip - turn off shutdown mode */
	325	int conf = lm77_read_value(client, LM77_REG_CONF);
	326	if (conf & 1)
	327	lm77_write_value(client, LM77_REG_CONF, conf & 0xfe);
	328	}
	329
efd2d117	330	static int lm77_probe(struct i2c_client client, const struct i2c_device_id id)
a189dd62	331	{
efd2d117	332	struct device *dev = &client->dev;
5975dfbf	333	struct device *hwmon_dev;
a189dd62	334	struct lm77_data *data;
a189dd62	335
52714c04 GR	336	data = devm_kzalloc(dev, sizeof(struct lm77_data), GFP_KERNEL);
	337	if (!data)
	338	return -ENOMEM;
1da177e4	339
5975dfbf	340	data->client = client;
9a61bf63	341	mutex_init(&data->update_lock);
1da177e4	342
1da177e4	343	/* Initialize the LM77 chip */
efd2d117	344	lm77_init_client(client);
1da177e4	345
5975dfbf GR	346	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
	347	data, lm77_groups);
	348	return PTR_ERR_OR_ZERO(hwmon_dev);
1da177e4 LT	349	}
1da177e4 LT	350
9f9edcd4 GR	351	static const struct i2c_device_id lm77_id[] = {
	352	{ "lm77", 0 },
	353	{ }
	354	};
	355	MODULE_DEVICE_TABLE(i2c, lm77_id);
1da177e4	356
9f9edcd4 GR	357	/* This is the driver that will be inserted */
	358	static struct i2c_driver lm77_driver = {
	359	.class = I2C_CLASS_HWMON,
	360	.driver = {
	361	.name = "lm77",
	362	},
	363	.probe = lm77_probe,
9f9edcd4 GR	364	.id_table = lm77_id,
	365	.detect = lm77_detect,
	366	.address_list = normal_i2c,
	367	};
1da177e4	368
f0967eea	369	module_i2c_driver(lm77_driver);
1da177e4 LT	370
	371	MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>");
	372	MODULE_DESCRIPTION("LM77 driver");
	373	MODULE_LICENSE("GPL");