[linux-block.git] / drivers / hwmon / lm77.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * 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
 */

#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;
	bool			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 = true;
	}

	mutex_unlock(&data->update_lock);

	return data;
}

/* sysfs stuff */

static ssize_t temp_show(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 temp_hyst_show(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 temp_store(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 temp_hyst_store(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 alarm_show(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_RO(temp1_input, temp, t_input);
static SENSOR_DEVICE_ATTR_RW(temp1_crit, temp, t_crit);
static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, t_min);
static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, t_max);

static SENSOR_DEVICE_ATTR_RW(temp1_crit_hyst, temp_hyst, t_crit);
static SENSOR_DEVICE_ATTR_RO(temp1_min_hyst, temp_hyst, t_min);
static SENSOR_DEVICE_ATTR_RO(temp1_max_hyst, temp_hyst, t_max);

static SENSOR_DEVICE_ATTR_RO(temp1_crit_alarm, alarm, 2);
static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, 0);
static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 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;

	strscpy(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)
{
	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_new	= 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
c942fddf	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4	2	/*
02fe2fd9 GR	3	* lm77.c - Part of lm_sensors, Linux kernel modules for hardware
	4	* monitoring
	5	*
	6	* Copyright (c) 2004 Andras BALI <drewie@freemail.hu>
	7	*
	8	* Heavily based on lm75.c by Frodo Looijaard <frodol@dds.nl>. The LM77
	9	* is a temperature sensor and thermal window comparator with 0.5 deg
	10	* resolution made by National Semiconductor. Complete datasheet can be
	11	* obtained at their site:
	12	* http://www.national.com/pf/LM/LM77.html
02fe2fd9	13	*/
1da177e4	14
1da177e4 LT	15	#include <linux/module.h>
	16	#include <linux/init.h>
	17	#include <linux/slab.h>
	18	#include <linux/jiffies.h>
	19	#include <linux/i2c.h>
943b0830	20	#include <linux/hwmon.h>
1f52af0f	21	#include <linux/hwmon-sysfs.h>
943b0830	22	#include <linux/err.h>
9a61bf63	23	#include <linux/mutex.h>
1da177e4 LT	24
1da177e4 LT	25	/* Addresses to scan */
25e9c86d MH	26	static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
25e9c86d MH	27	I2C_CLIENT_END };
1da177e4	28
1da177e4 LT	29	/* The LM77 registers */
	30	#define LM77_REG_TEMP 0x00
	31	#define LM77_REG_CONF 0x01
	32	#define LM77_REG_TEMP_HYST 0x02
	33	#define LM77_REG_TEMP_CRIT 0x03
	34	#define LM77_REG_TEMP_MIN 0x04
	35	#define LM77_REG_TEMP_MAX 0x05
	36
48dbd6ff GR	37	enum temp_index {
	38	t_input = 0,
	39	t_crit,
	40	t_min,
	41	t_max,
	42	t_hyst,
	43	t_num_temp
	44	};
	45
	46	static const u8 temp_regs[t_num_temp] = {
	47	[t_input] = LM77_REG_TEMP,
	48	[t_min] = LM77_REG_TEMP_MIN,
	49	[t_max] = LM77_REG_TEMP_MAX,
	50	[t_crit] = LM77_REG_TEMP_CRIT,
	51	[t_hyst] = LM77_REG_TEMP_HYST,
	52	};
	53
1da177e4 LT	54	/* Each client has this additional data */
1da177e4 LT	55	struct lm77_data {
5975dfbf	56	struct i2c_client *client;
9a61bf63	57	struct mutex update_lock;
952a11ca	58	bool valid;
1da177e4	59	unsigned long last_updated; /* In jiffies */
48dbd6ff	60	int temp[t_num_temp]; /* index using temp_index */
1da177e4 LT	61	u8 alarms;
	62	};
	63
1da177e4 LT	64	/* straight from the datasheet */
	65	#define LM77_TEMP_MIN (-55000)
	66	#define LM77_TEMP_MAX 125000
	67
02fe2fd9 GR	68	/*
	69	* In the temperature registers, the low 3 bits are not part of the
	70	* temperature values; they are the status bits.
	71	*/
413b6451	72	static inline s16 LM77_TEMP_TO_REG(int temp)
1da177e4	73	{
99765db2	74	return (temp / 500) * 8;
1da177e4 LT	75	}
1da177e4 LT	76
413b6451	77	static inline int LM77_TEMP_FROM_REG(s16 reg)
1da177e4	78	{
413b6451	79	return (reg / 8) * 500;
1da177e4 LT	80	}
1da177e4 LT	81
9f9edcd4 GR	82	/*
	83	* All registers are word-sized, except for the configuration register.
	84	* The LM77 uses the high-byte first convention.
	85	*/
	86	static u16 lm77_read_value(struct i2c_client *client, u8 reg)
	87	{
	88	if (reg == LM77_REG_CONF)
	89	return i2c_smbus_read_byte_data(client, reg);
	90	else
	91	return i2c_smbus_read_word_swapped(client, reg);
	92	}
	93
	94	static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value)
	95	{
	96	if (reg == LM77_REG_CONF)
	97	return i2c_smbus_write_byte_data(client, reg, value);
	98	else
	99	return i2c_smbus_write_word_swapped(client, reg, value);
	100	}
	101
	102	static struct lm77_data lm77_update_device(struct device dev)
	103	{
5975dfbf GR	104	struct lm77_data *data = dev_get_drvdata(dev);
5975dfbf GR	105	struct i2c_client *client = data->client;
48dbd6ff	106	int i;
9f9edcd4 GR	107
	108	mutex_lock(&data->update_lock);
	109
	110	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
	111	\|\| !data->valid) {
	112	dev_dbg(&client->dev, "Starting lm77 update\n");
48dbd6ff GR	113	for (i = 0; i < t_num_temp; i++) {
	114	data->temp[i] =
	115	LM77_TEMP_FROM_REG(lm77_read_value(client,
	116	temp_regs[i]));
	117	}
9f9edcd4 GR	118	data->alarms =
	119	lm77_read_value(client, LM77_REG_TEMP) & 0x0007;
	120	data->last_updated = jiffies;
952a11ca	121	data->valid = true;
9f9edcd4 GR	122	}
	123
	124	mutex_unlock(&data->update_lock);
	125
	126	return data;
	127	}
	128
1da177e4 LT	129	/* sysfs stuff */
1da177e4 LT	130
97b539d5	131	static ssize_t temp_show(struct device dev, struct device_attribute devattr,
48dbd6ff	132	char *buf)
1da177e4	133	{
48dbd6ff	134	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
1da177e4	135	struct lm77_data *data = lm77_update_device(dev);
48dbd6ff GR	136
48dbd6ff GR	137	return sprintf(buf, "%d\n", data->temp[attr->index]);
1da177e4	138	}
48dbd6ff	139
97b539d5	140	static ssize_t temp_hyst_show(struct device *dev,
48dbd6ff	141	struct device_attribute devattr, 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	int nr = attr->index;
48dbd6ff GR	146	int temp;
1da177e4	147
48dbd6ff GR	148	temp = nr == t_min ? data->temp[nr] + data->temp[t_hyst] :
48dbd6ff GR	149	data->temp[nr] - data->temp[t_hyst];
1da177e4	150
48dbd6ff GR	151	return sprintf(buf, "%d\n", temp);
48dbd6ff GR	152	}
1da177e4	153
97b539d5 GR	154	static ssize_t temp_store(struct device *dev,
	155	struct device_attribute devattr, const char buf,
	156	size_t count)
1da177e4	157	{
48dbd6ff	158	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
5975dfbf GR	159	struct lm77_data *data = dev_get_drvdata(dev);
5975dfbf GR	160	struct i2c_client *client = data->client;
48dbd6ff GR	161	int nr = attr->index;
48dbd6ff GR	162	long val;
02fe2fd9 GR	163	int err;
02fe2fd9 GR	164
48dbd6ff	165	err = kstrtol(buf, 10, &val);
02fe2fd9 GR	166	if (err)
02fe2fd9 GR	167	return err;
1da177e4	168
99765db2	169	val = clamp_val(val, LM77_TEMP_MIN, LM77_TEMP_MAX);
9a61bf63	170	mutex_lock(&data->update_lock);
48dbd6ff GR	171	data->temp[nr] = val;
48dbd6ff GR	172	lm77_write_value(client, temp_regs[nr], LM77_TEMP_TO_REG(val));
9a61bf63	173	mutex_unlock(&data->update_lock);
1da177e4 LT	174	return count;
	175	}
	176
48dbd6ff GR	177	/*
	178	* hysteresis is stored as a relative value on the chip, so it has to be
	179	* converted first.
	180	*/
97b539d5 GR	181	static ssize_t temp_hyst_store(struct device *dev,
	182	struct device_attribute *devattr,
	183	const char *buf, size_t count)
1da177e4	184	{
5975dfbf GR	185	struct lm77_data *data = dev_get_drvdata(dev);
5975dfbf GR	186	struct i2c_client *client = data->client;
99765db2	187	long val;
02fe2fd9 GR	188	int err;
02fe2fd9 GR	189
99765db2	190	err = kstrtol(buf, 10, &val);
02fe2fd9 GR	191	if (err)
	192	return err;
	193
9a61bf63	194	mutex_lock(&data->update_lock);
99765db2 AL	195	val = clamp_val(data->temp[t_crit] - val, LM77_TEMP_MIN, LM77_TEMP_MAX);
99765db2 AL	196	data->temp[t_hyst] = val;
48dbd6ff GR	197	lm77_write_value(client, LM77_REG_TEMP_HYST,
48dbd6ff GR	198	LM77_TEMP_TO_REG(data->temp[t_hyst]));
9a61bf63	199	mutex_unlock(&data->update_lock);
1da177e4 LT	200	return count;
	201	}
	202
97b539d5	203	static ssize_t alarm_show(struct device dev, struct device_attribute attr,
1f52af0f JD	204	char *buf)
	205	{
	206	int bitnr = to_sensor_dev_attr(attr)->index;
	207	struct lm77_data *data = lm77_update_device(dev);
	208	return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1);
	209	}
	210
97b539d5 GR	211	static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, t_input);
	212	static SENSOR_DEVICE_ATTR_RW(temp1_crit, temp, t_crit);
	213	static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, t_min);
	214	static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, t_max);
	215
	216	static SENSOR_DEVICE_ATTR_RW(temp1_crit_hyst, temp_hyst, t_crit);
	217	static SENSOR_DEVICE_ATTR_RO(temp1_min_hyst, temp_hyst, t_min);
	218	static SENSOR_DEVICE_ATTR_RO(temp1_max_hyst, temp_hyst, t_max);
	219
	220	static SENSOR_DEVICE_ATTR_RO(temp1_crit_alarm, alarm, 2);
	221	static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, 0);
	222	static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 1);
1da177e4	223
5975dfbf	224	static struct attribute *lm77_attrs[] = {
48dbd6ff GR	225	&sensor_dev_attr_temp1_input.dev_attr.attr,
	226	&sensor_dev_attr_temp1_crit.dev_attr.attr,
	227	&sensor_dev_attr_temp1_min.dev_attr.attr,
	228	&sensor_dev_attr_temp1_max.dev_attr.attr,
	229	&sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
	230	&sensor_dev_attr_temp1_min_hyst.dev_attr.attr,
	231	&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
1f52af0f JD	232	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
	233	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
	234	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
0501a381 MH	235	NULL
0501a381 MH	236	};
5975dfbf	237	ATTRIBUTE_GROUPS(lm77);
0501a381	238
a189dd62	239	/* Return 0 if detection is successful, -ENODEV otherwise */
efd2d117	240	static int lm77_detect(struct i2c_client client, struct i2c_board_info info)
1da177e4	241	{
efd2d117	242	struct i2c_adapter *adapter = client->adapter;
747d9bed	243	int i, cur, conf, hyst, crit, min, max;
1da177e4 LT	244
	245	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA \|
	246	I2C_FUNC_SMBUS_WORD_DATA))
a189dd62	247	return -ENODEV;
1da177e4	248
02fe2fd9 GR	249	/*
	250	* Here comes the remaining detection. Since the LM77 has no
	251	* register dedicated to identification, we have to rely on the
	252	* following tricks:
	253	*
	254	* 1. the high 4 bits represent the sign and thus they should
	255	* always be the same
	256	* 2. the high 3 bits are unused in the configuration register
	257	* 3. addresses 0x06 and 0x07 return the last read value
	258	* 4. registers cycling over 8-address boundaries
	259	*
	260	* Word-sized registers are high-byte first.
	261	*/
1da177e4	262
747d9bed	263	/* addresses cycling */
efd2d117 GR	264	cur = i2c_smbus_read_word_data(client, 0);
	265	conf = i2c_smbus_read_byte_data(client, 1);
	266	hyst = i2c_smbus_read_word_data(client, 2);
	267	crit = i2c_smbus_read_word_data(client, 3);
	268	min = i2c_smbus_read_word_data(client, 4);
	269	max = i2c_smbus_read_word_data(client, 5);
747d9bed	270	for (i = 8; i <= 0xff; i += 8) {
efd2d117 GR	271	if (i2c_smbus_read_byte_data(client, i + 1) != conf
	272	\|\| i2c_smbus_read_word_data(client, i + 2) != hyst
	273	\|\| i2c_smbus_read_word_data(client, i + 3) != crit
	274	\|\| i2c_smbus_read_word_data(client, i + 4) != min
	275	\|\| i2c_smbus_read_word_data(client, i + 5) != max)
a189dd62	276	return -ENODEV;
747d9bed	277	}
1da177e4	278
747d9bed JD	279	/* sign bits */
	280	if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0)
	281	\|\| ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0)
	282	\|\| ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0)
	283	\|\| ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0)
	284	\|\| ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0))
	285	return -ENODEV;
1da177e4	286
747d9bed JD	287	/* unused bits */
	288	if (conf & 0xe0)
	289	return -ENODEV;
	290
	291	/* 0x06 and 0x07 return the last read value */
efd2d117 GR	292	cur = i2c_smbus_read_word_data(client, 0);
	293	if (i2c_smbus_read_word_data(client, 6) != cur
	294	\|\| i2c_smbus_read_word_data(client, 7) != cur)
747d9bed	295	return -ENODEV;
efd2d117 GR	296	hyst = i2c_smbus_read_word_data(client, 2);
	297	if (i2c_smbus_read_word_data(client, 6) != hyst
	298	\|\| i2c_smbus_read_word_data(client, 7) != hyst)
747d9bed	299	return -ENODEV;
efd2d117 GR	300	min = i2c_smbus_read_word_data(client, 4);
	301	if (i2c_smbus_read_word_data(client, 6) != min
	302	\|\| i2c_smbus_read_word_data(client, 7) != min)
747d9bed	303	return -ENODEV;
1da177e4	304
f2f394db	305	strscpy(info->type, "lm77", I2C_NAME_SIZE);
1da177e4	306
a189dd62 JD	307	return 0;
	308	}
	309
9f9edcd4 GR	310	static void lm77_init_client(struct i2c_client *client)
	311	{
	312	/* Initialize the LM77 chip - turn off shutdown mode */
	313	int conf = lm77_read_value(client, LM77_REG_CONF);
	314	if (conf & 1)
	315	lm77_write_value(client, LM77_REG_CONF, conf & 0xfe);
	316	}
	317
67487038	318	static int lm77_probe(struct i2c_client *client)
a189dd62	319	{
efd2d117	320	struct device *dev = &client->dev;
5975dfbf	321	struct device *hwmon_dev;
a189dd62	322	struct lm77_data *data;
a189dd62	323
52714c04 GR	324	data = devm_kzalloc(dev, sizeof(struct lm77_data), GFP_KERNEL);
	325	if (!data)
	326	return -ENOMEM;
1da177e4	327
5975dfbf	328	data->client = client;
9a61bf63	329	mutex_init(&data->update_lock);
1da177e4	330
1da177e4	331	/* Initialize the LM77 chip */
efd2d117	332	lm77_init_client(client);
1da177e4	333
5975dfbf GR	334	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
	335	data, lm77_groups);
	336	return PTR_ERR_OR_ZERO(hwmon_dev);
1da177e4 LT	337	}
1da177e4 LT	338
9f9edcd4 GR	339	static const struct i2c_device_id lm77_id[] = {
	340	{ "lm77", 0 },
	341	{ }
	342	};
	343	MODULE_DEVICE_TABLE(i2c, lm77_id);
1da177e4	344
9f9edcd4 GR	345	/* This is the driver that will be inserted */
	346	static struct i2c_driver lm77_driver = {
	347	.class = I2C_CLASS_HWMON,
	348	.driver = {
	349	.name = "lm77",
	350	},
67487038	351	.probe_new = lm77_probe,
9f9edcd4 GR	352	.id_table = lm77_id,
	353	.detect = lm77_detect,
	354	.address_list = normal_i2c,
	355	};
1da177e4	356
f0967eea	357	module_i2c_driver(lm77_driver);
1da177e4 LT	358
	359	MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>");
	360	MODULE_DESCRIPTION("LM77 driver");
	361	MODULE_LICENSE("GPL");