[mirror_ubuntu-zesty-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.

    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/i2c-sensor.h>


/* Addresses to scan */
static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, I2C_CLIENT_END };
static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END };

/* Insmod parameters */
SENSORS_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 i2c_client	client;
	struct semaphore	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_attach_adapter(struct i2c_adapter *adapter);
static int lm77_detect(struct i2c_adapter *adapter, int address, int kind);
static void lm77_init_client(struct i2c_client *client);
static int lm77_detach_client(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);


/* This is the driver that will be inserted */
static struct i2c_driver lm77_driver = {
	.owner		= THIS_MODULE,
	.name		= "lm77",
	.flags		= I2C_DF_NOTIFY,
	.attach_adapter = lm77_attach_adapter,
	.detach_client	= lm77_detach_client,
};

/* 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 u16 LM77_TEMP_TO_REG(int temp)
{
	int ntemp = SENSORS_LIMIT(temp, LM77_TEMP_MIN, LM77_TEMP_MAX);
	return (u16)((ntemp / 500) * 8);
}

static inline int LM77_TEMP_FROM_REG(u16 reg)
{
	return ((int)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);
show(alarms);

/* 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_strtoul(buf, NULL, 10);				\
										\
	down(&data->update_lock);						\
	data->value = val;				\
	lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value));		\
	up(&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);

	down(&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));
	up(&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;
	
	down(&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));
	up(&data->update_lock);
	return count;
}

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 DEVICE_ATTR(alarms, S_IRUGO,
		   show_alarms, NULL);

static int lm77_attach_adapter(struct i2c_adapter *adapter)
{
	if (!(adapter->class & I2C_CLASS_HWMON))
		return 0;
	return i2c_detect(adapter, &addr_data, lm77_detect);
}

/* This function is called by i2c_detect */
static int lm77_detect(struct i2c_adapter *adapter, int address, int kind)
{
	struct i2c_client *new_client;
	struct lm77_data *data;
	int err = 0;
	const char *name = "";

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
				     I2C_FUNC_SMBUS_WORD_DATA))
		goto exit;

	/* OK. For now, we presume we have a valid client. We now create the
	   client structure, even though we cannot fill it completely yet.
	   But it allows us to access lm77_{read,write}_value. */
	if (!(data = kmalloc(sizeof(struct lm77_data), GFP_KERNEL))) {
		err = -ENOMEM;
		goto exit;
	}
	memset(data, 0, sizeof(struct lm77_data));

	new_client = &data->client;
	i2c_set_clientdata(new_client, data);
	new_client->addr = address;
	new_client->adapter = adapter;
	new_client->driver = &lm77_driver;
	new_client->flags = 0;

	/* 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. */
	if (kind < 0) {
		int i, cur, conf, hyst, crit, min, max;

		/* 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)
				goto exit_free;

		/* 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))
			goto exit_free;

		/* unused bits */
		if (conf & 0xe0)
			goto exit_free;

		/* 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)
			goto exit_free;
		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)
			goto exit_free;
		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)
			goto exit_free;

	}

	/* Determine the chip type - only one kind supported! */
	if (kind <= 0)
		kind = lm77;

	if (kind == lm77) {
		name = "lm77";
	}

	/* Fill in the remaining client fields and put it into the global list */
	strlcpy(new_client->name, name, I2C_NAME_SIZE);
	data->valid = 0;
	init_MUTEX(&data->update_lock);

	/* Tell the I2C layer a new client has arrived */
	if ((err = i2c_attach_client(new_client)))
		goto exit_free;

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

	/* Register sysfs hooks */
	device_create_file(&new_client->dev, &dev_attr_temp1_input);
	device_create_file(&new_client->dev, &dev_attr_temp1_crit);
	device_create_file(&new_client->dev, &dev_attr_temp1_min);
	device_create_file(&new_client->dev, &dev_attr_temp1_max);
	device_create_file(&new_client->dev, &dev_attr_temp1_crit_hyst);
	device_create_file(&new_client->dev, &dev_attr_temp1_min_hyst);
	device_create_file(&new_client->dev, &dev_attr_temp1_max_hyst);
	device_create_file(&new_client->dev, &dev_attr_alarms);
	return 0;

exit_free:
	kfree(data);
exit:
	return err;
}

static int lm77_detach_client(struct i2c_client *client)
{
	i2c_detach_client(client);
	kfree(i2c_get_clientdata(client));
	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);

	down(&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;
	}

	up(&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>
	33	#include <linux/i2c-sensor.h>
	34
	35
	36	/* Addresses to scan */
	37	static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, I2C_CLIENT_END };
	38	static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END };
	39
	40	/* Insmod parameters */
	41	SENSORS_INSMOD_1(lm77);
	42
	43	/* The LM77 registers */
	44	#define LM77_REG_TEMP 0x00
	45	#define LM77_REG_CONF 0x01
	46	#define LM77_REG_TEMP_HYST 0x02
	47	#define LM77_REG_TEMP_CRIT 0x03
	48	#define LM77_REG_TEMP_MIN 0x04
	49	#define LM77_REG_TEMP_MAX 0x05
	50
	51	/* Each client has this additional data */
	52	struct lm77_data {
	53	struct i2c_client client;
	54	struct semaphore update_lock;
	55	char valid;
	56	unsigned long last_updated; /* In jiffies */
	57	int temp_input; /* Temperatures */
	58	int temp_crit;
	59	int temp_min;
	60	int temp_max;
	61	int temp_hyst;
	62	u8 alarms;
	63	};
	64
	65	static int lm77_attach_adapter(struct i2c_adapter *adapter);
	66	static int lm77_detect(struct i2c_adapter *adapter, int address, int kind);
	67	static void lm77_init_client(struct i2c_client *client);
	68	static int lm77_detach_client(struct i2c_client *client);
	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
	75	/* This is the driver that will be inserted */
	76	static struct i2c_driver lm77_driver = {
	77	.owner = THIS_MODULE,
	78	.name = "lm77",
	79	.flags = I2C_DF_NOTIFY,
	80	.attach_adapter = lm77_attach_adapter,
	81	.detach_client = lm77_detach_client,
	82	};
	83
	84	/* straight from the datasheet */
	85	#define LM77_TEMP_MIN (-55000)
	86	#define LM77_TEMP_MAX 125000
	87
	88	/* In the temperature registers, the low 3 bits are not part of the
	89	temperature values; they are the status bits. */
	90	static inline u16 LM77_TEMP_TO_REG(int temp)
	91	{
92	int ntemp = SENSORS_LIMIT(temp, LM77_TEMP_MIN, LM77_TEMP_MAX);
93	return (u16)((ntemp / 500) * 8);
94	}
95
96	static inline int LM77_TEMP_FROM_REG(u16 reg)
97	{
98	return ((int)reg / 8) * 500;
99	}
100
101	/* sysfs stuff */
102
103	/* read routines for temperature limits */
104	#define show(value) \
8627f9ba	105	static ssize_t show_##value(struct device dev, struct device_attribute attr, char *buf) \
1da177e4 LT	106	{ \
	107	struct lm77_data *data = lm77_update_device(dev); \
	108	return sprintf(buf, "%d\n", data->value); \
	109	}
	110
	111	show(temp_input);
	112	show(temp_crit);
	113	show(temp_min);
	114	show(temp_max);
	115	show(alarms);
	116
	117	/* read routines for hysteresis values */
8627f9ba	118	static ssize_t show_temp_crit_hyst(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->temp_crit - data->temp_hyst);
	122	}
8627f9ba	123	static ssize_t show_temp_min_hyst(struct device dev, struct device_attribute attr, char *buf)
1da177e4 LT	124	{
	125	struct lm77_data *data = lm77_update_device(dev);
	126	return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst);
	127	}
8627f9ba	128	static ssize_t show_temp_max_hyst(struct device dev, struct device_attribute attr, char *buf)
1da177e4 LT	129	{
	130	struct lm77_data *data = lm77_update_device(dev);
	131	return sprintf(buf, "%d\n", data->temp_max - data->temp_hyst);
	132	}
	133
	134	/* write routines */
	135	#define set(value, reg) \
8627f9ba	136	static ssize_t set_##value(struct device dev, struct device_attribute attr, const char *buf, size_t count) \
1da177e4 LT	137	{ \
	138	struct i2c_client *client = to_i2c_client(dev); \
	139	struct lm77_data *data = i2c_get_clientdata(client); \
	140	long val = simple_strtoul(buf, NULL, 10); \
	141	\
	142	down(&data->update_lock); \
	143	data->value = val; \
	144	lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value)); \
	145	up(&data->update_lock); \
	146	return count; \
	147	}
	148
	149	set(temp_min, LM77_REG_TEMP_MIN);
	150	set(temp_max, LM77_REG_TEMP_MAX);
	151
	152	/* hysteresis is stored as a relative value on the chip, so it has to be
	153	converted first */
8627f9ba	154	static ssize_t set_temp_crit_hyst(struct device dev, struct device_attribute attr, const char *buf, size_t count)
1da177e4 LT	155	{
	156	struct i2c_client *client = to_i2c_client(dev);
	157	struct lm77_data *data = i2c_get_clientdata(client);
	158	unsigned long val = simple_strtoul(buf, NULL, 10);
	159
	160	down(&data->update_lock);
	161	data->temp_hyst = data->temp_crit - val;
	162	lm77_write_value(client, LM77_REG_TEMP_HYST,
	163	LM77_TEMP_TO_REG(data->temp_hyst));
	164	up(&data->update_lock);
	165	return count;
	166	}
	167
	168	/* preserve hysteresis when setting T_crit */
8627f9ba	169	static ssize_t set_temp_crit(struct device dev, struct device_attribute attr, const char *buf, size_t count)
1da177e4 LT	170	{
	171	struct i2c_client *client = to_i2c_client(dev);
	172	struct lm77_data *data = i2c_get_clientdata(client);
	173	long val = simple_strtoul(buf, NULL, 10);
	174	int oldcrithyst;
	175
	176	down(&data->update_lock);
	177	oldcrithyst = data->temp_crit - data->temp_hyst;
	178	data->temp_crit = val;
	179	data->temp_hyst = data->temp_crit - oldcrithyst;
	180	lm77_write_value(client, LM77_REG_TEMP_CRIT,
	181	LM77_TEMP_TO_REG(data->temp_crit));
	182	lm77_write_value(client, LM77_REG_TEMP_HYST,
	183	LM77_TEMP_TO_REG(data->temp_hyst));
	184	up(&data->update_lock);
	185	return count;
	186	}
	187
	188	static DEVICE_ATTR(temp1_input, S_IRUGO,
	189	show_temp_input, NULL);
	190	static DEVICE_ATTR(temp1_crit, S_IWUSR \| S_IRUGO,
	191	show_temp_crit, set_temp_crit);
	192	static DEVICE_ATTR(temp1_min, S_IWUSR \| S_IRUGO,
	193	show_temp_min, set_temp_min);
	194	static DEVICE_ATTR(temp1_max, S_IWUSR \| S_IRUGO,
	195	show_temp_max, set_temp_max);
	196
	197	static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR \| S_IRUGO,
	198	show_temp_crit_hyst, set_temp_crit_hyst);
	199	static DEVICE_ATTR(temp1_min_hyst, S_IRUGO,
	200	show_temp_min_hyst, NULL);
	201	static DEVICE_ATTR(temp1_max_hyst, S_IRUGO,
	202	show_temp_max_hyst, NULL);
	203
	204	static DEVICE_ATTR(alarms, S_IRUGO,
	205	show_alarms, NULL);
	206
	207	static int lm77_attach_adapter(struct i2c_adapter *adapter)
	208	{
	209	if (!(adapter->class & I2C_CLASS_HWMON))
	210	return 0;
	211	return i2c_detect(adapter, &addr_data, lm77_detect);
	212	}
	213
	214	/* This function is called by i2c_detect */
	215	static int lm77_detect(struct i2c_adapter *adapter, int address, int kind)
	216	{
	217	struct i2c_client *new_client;
	218	struct lm77_data *data;
	219	int err = 0;
	220	const char *name = "";
	221
	222	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA \|
	223	I2C_FUNC_SMBUS_WORD_DATA))
	224	goto exit;
	225
	226	/* OK. For now, we presume we have a valid client. We now create the
	227	client structure, even though we cannot fill it completely yet.
	228	But it allows us to access lm77_{read,write}_value. */
	229	if (!(data = kmalloc(sizeof(struct lm77_data), GFP_KERNEL))) {
	230	err = -ENOMEM;
	231	goto exit;
	232	}
	233	memset(data, 0, sizeof(struct lm77_data));
234
235	new_client = &data->client;
236	i2c_set_clientdata(new_client, data);
237	new_client->addr = address;
238	new_client->adapter = adapter;
239	new_client->driver = &lm77_driver;
240	new_client->flags = 0;
241
242	/* Here comes the remaining detection. Since the LM77 has no
243	register dedicated to identification, we have to rely on the
244	following tricks:
245
246	1. the high 4 bits represent the sign and thus they should
247	always be the same
248	2. the high 3 bits are unused in the configuration register
249	3. addresses 0x06 and 0x07 return the last read value
250	4. registers cycling over 8-address boundaries
251
252	Word-sized registers are high-byte first. */
253	if (kind < 0) {
254	int i, cur, conf, hyst, crit, min, max;
255
256	/* addresses cycling */
257	cur = i2c_smbus_read_word_data(new_client, 0);
258	conf = i2c_smbus_read_byte_data(new_client, 1);
259	hyst = i2c_smbus_read_word_data(new_client, 2);
260	crit = i2c_smbus_read_word_data(new_client, 3);
261	min = i2c_smbus_read_word_data(new_client, 4);
262	max = i2c_smbus_read_word_data(new_client, 5);
263	for (i = 8; i <= 0xff; i += 8)
264	if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
265	\|\| i2c_smbus_read_word_data(new_client, i + 2) != hyst
266	\|\| i2c_smbus_read_word_data(new_client, i + 3) != crit
267	\|\| i2c_smbus_read_word_data(new_client, i + 4) != min
268	\|\| i2c_smbus_read_word_data(new_client, i + 5) != max)
269	goto exit_free;
270
271	/* sign bits */
272	if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0)
273	\|\| ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0)
274	\|\| ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0)
275	\|\| ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0)
276	\|\| ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0))
277	goto exit_free;
278
279	/* unused bits */
280	if (conf & 0xe0)
281	goto exit_free;
282
283	/* 0x06 and 0x07 return the last read value */
284	cur = i2c_smbus_read_word_data(new_client, 0);
285	if (i2c_smbus_read_word_data(new_client, 6) != cur
286	\|\| i2c_smbus_read_word_data(new_client, 7) != cur)
287	goto exit_free;
288	hyst = i2c_smbus_read_word_data(new_client, 2);
289	if (i2c_smbus_read_word_data(new_client, 6) != hyst
290	\|\| i2c_smbus_read_word_data(new_client, 7) != hyst)
291	goto exit_free;
292	min = i2c_smbus_read_word_data(new_client, 4);
293	if (i2c_smbus_read_word_data(new_client, 6) != min
294	\|\| i2c_smbus_read_word_data(new_client, 7) != min)
295	goto exit_free;
296
297	}
298
299	/* Determine the chip type - only one kind supported! */
300	if (kind <= 0)
301	kind = lm77;
302
303	if (kind == lm77) {
304	name = "lm77";
305	}
306
307	/* Fill in the remaining client fields and put it into the global list */
308	strlcpy(new_client->name, name, I2C_NAME_SIZE);
309	data->valid = 0;
310	init_MUTEX(&data->update_lock);
311
312	/* Tell the I2C layer a new client has arrived */
313	if ((err = i2c_attach_client(new_client)))
314	goto exit_free;
315
316	/* Initialize the LM77 chip */
317	lm77_init_client(new_client);
318
319	/* Register sysfs hooks */
320	device_create_file(&new_client->dev, &dev_attr_temp1_input);
321	device_create_file(&new_client->dev, &dev_attr_temp1_crit);
322	device_create_file(&new_client->dev, &dev_attr_temp1_min);
323	device_create_file(&new_client->dev, &dev_attr_temp1_max);
324	device_create_file(&new_client->dev, &dev_attr_temp1_crit_hyst);
325	device_create_file(&new_client->dev, &dev_attr_temp1_min_hyst);
326	device_create_file(&new_client->dev, &dev_attr_temp1_max_hyst);
327	device_create_file(&new_client->dev, &dev_attr_alarms);
328	return 0;
329
330	exit_free:
331	kfree(data);
332	exit:
333	return err;
334	}
335
336	static int lm77_detach_client(struct i2c_client *client)
337	{
338	i2c_detach_client(client);
339	kfree(i2c_get_clientdata(client));
340	return 0;
341	}
342
343	/* All registers are word-sized, except for the configuration register.
344	The LM77 uses the high-byte first convention. */
345	static u16 lm77_read_value(struct i2c_client *client, u8 reg)
346	{
347	if (reg == LM77_REG_CONF)
348	return i2c_smbus_read_byte_data(client, reg);
349	else
350	return swab16(i2c_smbus_read_word_data(client, reg));
351	}
352
353	static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value)
354	{
355	if (reg == LM77_REG_CONF)
356	return i2c_smbus_write_byte_data(client, reg, value);
357	else
358	return i2c_smbus_write_word_data(client, reg, swab16(value));
359	}
360
361	static void lm77_init_client(struct i2c_client *client)
362	{
363	/* Initialize the LM77 chip - turn off shutdown mode */
364	int conf = lm77_read_value(client, LM77_REG_CONF);
365	if (conf & 1)
366	lm77_write_value(client, LM77_REG_CONF, conf & 0xfe);
367	}
368
369	static struct lm77_data lm77_update_device(struct device dev)
370	{
371	struct i2c_client *client = to_i2c_client(dev);
372	struct lm77_data *data = i2c_get_clientdata(client);
373
374	down(&data->update_lock);
375
376	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
377	\|\| !data->valid) {
378	dev_dbg(&client->dev, "Starting lm77 update\n");
379	data->temp_input =
380	LM77_TEMP_FROM_REG(lm77_read_value(client,
381	LM77_REG_TEMP));
382	data->temp_hyst =
383	LM77_TEMP_FROM_REG(lm77_read_value(client,
384	LM77_REG_TEMP_HYST));
385	data->temp_crit =
386	LM77_TEMP_FROM_REG(lm77_read_value(client,
387	LM77_REG_TEMP_CRIT));
388	data->temp_min =
389	LM77_TEMP_FROM_REG(lm77_read_value(client,
390	LM77_REG_TEMP_MIN));
391	data->temp_max =
392	LM77_TEMP_FROM_REG(lm77_read_value(client,
393	LM77_REG_TEMP_MAX));
394	data->alarms =
395	lm77_read_value(client, LM77_REG_TEMP) & 0x0007;
396	data->last_updated = jiffies;
397	data->valid = 1;
398	}
399
400	up(&data->update_lock);
401
402	return data;
403	}
404
405	static int __init sensors_lm77_init(void)
406	{
407	return i2c_add_driver(&lm77_driver);
408	}
409
410	static void __exit sensors_lm77_exit(void)
411	{
412	i2c_del_driver(&lm77_driver);
413	}
414
415	MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>");
416	MODULE_DESCRIPTION("LM77 driver");
417	MODULE_LICENSE("GPL");
418
419	module_init(sensors_lm77_init);
420	module_exit(sensors_lm77_exit);