[linux-block.git] / drivers / hwmon / pcf8591.c

/*
    Copyright (C) 2001-2004 Aurelien Jarno <aurelien@aurel32.net>
    Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
    the help of Jean Delvare <khali@linux-fr.org>

    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/i2c.h>
#include <linux/mutex.h>

/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
					0x4d, 0x4e, 0x4f, I2C_CLIENT_END };

/* Insmod parameters */
I2C_CLIENT_INSMOD_1(pcf8591);

static int input_mode;
module_param(input_mode, int, 0);
MODULE_PARM_DESC(input_mode,
	"Analog input mode:\n"
	" 0 = four single ended inputs\n"
	" 1 = three differential inputs\n"
	" 2 = single ended and differential mixed\n"
	" 3 = two differential inputs\n");

/* The PCF8591 control byte
      7    6    5    4    3    2    1    0
   |  0 |AOEF|   AIP   |  0 |AINC|  AICH   | */

/* Analog Output Enable Flag (analog output active if 1) */
#define PCF8591_CONTROL_AOEF		0x40

/* Analog Input Programming
   0x00 = four single ended inputs
   0x10 = three differential inputs
   0x20 = single ended and differential mixed
   0x30 = two differential inputs */
#define PCF8591_CONTROL_AIP_MASK	0x30

/* Autoincrement Flag (switch on if 1) */
#define PCF8591_CONTROL_AINC		0x04

/* Channel selection
   0x00 = channel 0
   0x01 = channel 1
   0x02 = channel 2
   0x03 = channel 3 */
#define PCF8591_CONTROL_AICH_MASK	0x03

/* Initial values */
#define PCF8591_INIT_CONTROL	((input_mode << 4) | PCF8591_CONTROL_AOEF)
#define PCF8591_INIT_AOUT	0	/* DAC out = 0 */

/* Conversions */
#define REG_TO_SIGNED(reg)	(((reg) & 0x80)?((reg) - 256):(reg))

struct pcf8591_data {
	struct mutex update_lock;

	u8 control;
	u8 aout;
};

static void pcf8591_init_client(struct i2c_client *client);
static int pcf8591_read_channel(struct device *dev, int channel);

/* following are the sysfs callback functions */
#define show_in_channel(channel)					\
static ssize_t show_in##channel##_input(struct device *dev, struct device_attribute *attr, char *buf)	\
{									\
	return sprintf(buf, "%d\n", pcf8591_read_channel(dev, channel));\
}									\
static DEVICE_ATTR(in##channel##_input, S_IRUGO,			\
		   show_in##channel##_input, NULL);

show_in_channel(0);
show_in_channel(1);
show_in_channel(2);
show_in_channel(3);

static ssize_t show_out0_ouput(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
	return sprintf(buf, "%d\n", data->aout * 10);
}

static ssize_t set_out0_output(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
	unsigned int value;
	struct i2c_client *client = to_i2c_client(dev);
	struct pcf8591_data *data = i2c_get_clientdata(client);
	if ((value = (simple_strtoul(buf, NULL, 10) + 5) / 10) <= 255) {
		data->aout = value;
		i2c_smbus_write_byte_data(client, data->control, data->aout);
		return count;
	}
	return -EINVAL;
}

static DEVICE_ATTR(out0_output, S_IWUSR | S_IRUGO,
		   show_out0_ouput, set_out0_output);

static ssize_t show_out0_enable(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
	return sprintf(buf, "%u\n", !(!(data->control & PCF8591_CONTROL_AOEF)));
}

static ssize_t set_out0_enable(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct pcf8591_data *data = i2c_get_clientdata(client);
	unsigned long val = simple_strtoul(buf, NULL, 10);

	mutex_lock(&data->update_lock);
	if (val)
		data->control |= PCF8591_CONTROL_AOEF;
	else
		data->control &= ~PCF8591_CONTROL_AOEF;
	i2c_smbus_write_byte(client, data->control);
	mutex_unlock(&data->update_lock);
	return count;
}

static DEVICE_ATTR(out0_enable, S_IWUSR | S_IRUGO,
		   show_out0_enable, set_out0_enable);

static struct attribute *pcf8591_attributes[] = {
	&dev_attr_out0_enable.attr,
	&dev_attr_out0_output.attr,
	&dev_attr_in0_input.attr,
	&dev_attr_in1_input.attr,
	NULL
};

static const struct attribute_group pcf8591_attr_group = {
	.attrs = pcf8591_attributes,
};

static struct attribute *pcf8591_attributes_opt[] = {
	&dev_attr_in2_input.attr,
	&dev_attr_in3_input.attr,
	NULL
};

static const struct attribute_group pcf8591_attr_group_opt = {
	.attrs = pcf8591_attributes_opt,
};

/*
 * Real code
 */

/* Return 0 if detection is successful, -ENODEV otherwise */
static int pcf8591_detect(struct i2c_client *client, int kind,
			  struct i2c_board_info *info)
{
	struct i2c_adapter *adapter = client->adapter;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE
				     | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
		return -ENODEV;

	/* Now, we would do the remaining detection. But the PCF8591 is plainly
	   impossible to detect! Stupid chip. */

	strlcpy(info->type, "pcf8591", I2C_NAME_SIZE);

	return 0;
}

static int pcf8591_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct pcf8591_data *data;
	int err;

	if (!(data = kzalloc(sizeof(struct pcf8591_data), GFP_KERNEL))) {
		err = -ENOMEM;
		goto exit;
	}

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

	/* Initialize the PCF8591 chip */
	pcf8591_init_client(client);

	/* Register sysfs hooks */
	err = sysfs_create_group(&client->dev.kobj, &pcf8591_attr_group);
	if (err)
		goto exit_kfree;

	/* Register input2 if not in "two differential inputs" mode */
	if (input_mode != 3) {
		if ((err = device_create_file(&client->dev,
					      &dev_attr_in2_input)))
			goto exit_sysfs_remove;
	}

	/* Register input3 only in "four single ended inputs" mode */
	if (input_mode == 0) {
		if ((err = device_create_file(&client->dev,
					      &dev_attr_in3_input)))
			goto exit_sysfs_remove;
	}

	return 0;

exit_sysfs_remove:
	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
exit_kfree:
	kfree(data);
exit:
	return err;
}

static int pcf8591_remove(struct i2c_client *client)
{
	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
	kfree(i2c_get_clientdata(client));
	return 0;
}

/* Called when we have found a new PCF8591. */
static void pcf8591_init_client(struct i2c_client *client)
{
	struct pcf8591_data *data = i2c_get_clientdata(client);
	data->control = PCF8591_INIT_CONTROL;
	data->aout = PCF8591_INIT_AOUT;

	i2c_smbus_write_byte_data(client, data->control, data->aout);

	/* The first byte transmitted contains the conversion code of the
	   previous read cycle. FLUSH IT! */
	i2c_smbus_read_byte(client);
}

static int pcf8591_read_channel(struct device *dev, int channel)
{
	u8 value;
	struct i2c_client *client = to_i2c_client(dev);
	struct pcf8591_data *data = i2c_get_clientdata(client);

	mutex_lock(&data->update_lock);

	if ((data->control & PCF8591_CONTROL_AICH_MASK) != channel) {
		data->control = (data->control & ~PCF8591_CONTROL_AICH_MASK)
			      | channel;
		i2c_smbus_write_byte(client, data->control);

		/* The first byte transmitted contains the conversion code of
		   the previous read cycle. FLUSH IT! */
		i2c_smbus_read_byte(client);
	}
	value = i2c_smbus_read_byte(client);

	mutex_unlock(&data->update_lock);

	if ((channel == 2 && input_mode == 2) ||
	    (channel != 3 && (input_mode == 1 || input_mode == 3)))
		return (10 * REG_TO_SIGNED(value));
	else
		return (10 * value);
}

static const struct i2c_device_id pcf8591_id[] = {
	{ "pcf8591", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, pcf8591_id);

static struct i2c_driver pcf8591_driver = {
	.driver = {
		.name	= "pcf8591",
	},
	.probe		= pcf8591_probe,
	.remove		= pcf8591_remove,
	.id_table	= pcf8591_id,

	.class		= I2C_CLASS_HWMON,	/* Nearest choice */
	.detect		= pcf8591_detect,
	.address_data	= &addr_data,
};

static int __init pcf8591_init(void)
{
	if (input_mode < 0 || input_mode > 3) {
		printk(KERN_WARNING "pcf8591: invalid input_mode (%d)\n",
		       input_mode);
		input_mode = 0;
	}
	return i2c_add_driver(&pcf8591_driver);
}

static void __exit pcf8591_exit(void)
{
	i2c_del_driver(&pcf8591_driver);
}

MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
MODULE_DESCRIPTION("PCF8591 driver");
MODULE_LICENSE("GPL");

module_init(pcf8591_init);
module_exit(pcf8591_exit);
Commit	Line	Data
1da177e4	1	/*
1da177e4	2	Copyright (C) 2001-2004 Aurelien Jarno <aurelien@aurel32.net>
fb4504fe	3	Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
1da177e4 LT	4	the help of Jean Delvare <khali@linux-fr.org>
	5
	6	This program is free software; you can redistribute it and/or modify
	7	it under the terms of the GNU General Public License as published by
	8	the Free Software Foundation; either version 2 of the License, or
	9	(at your option) any later version.
	10
	11	This program is distributed in the hope that it will be useful,
	12	but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	GNU General Public License for more details.
	15
	16	You should have received a copy of the GNU General Public License
	17	along with this program; if not, write to the Free Software
	18	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	19	*/
	20
	21	#include <linux/module.h>
	22	#include <linux/init.h>
	23	#include <linux/slab.h>
	24	#include <linux/i2c.h>
5c085d36	25	#include <linux/mutex.h>
1da177e4 LT	26
1da177e4 LT	27	/* Addresses to scan */
2cdddeb8	28	static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
1da177e4	29	0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
1da177e4 LT	30
1da177e4 LT	31	/* Insmod parameters */
f4b50261	32	I2C_CLIENT_INSMOD_1(pcf8591);
1da177e4 LT	33
	34	static int input_mode;
	35	module_param(input_mode, int, 0);
	36	MODULE_PARM_DESC(input_mode,
	37	"Analog input mode:\n"
	38	" 0 = four single ended inputs\n"
	39	" 1 = three differential inputs\n"
	40	" 2 = single ended and differential mixed\n"
	41	" 3 = two differential inputs\n");
	42
	43	/* The PCF8591 control byte
fb4504fe	44	7 6 5 4 3 2 1 0
1da177e4 LT	45	\| 0 \|AOEF\| AIP \| 0 \|AINC\| AICH \| */
	46
	47	/* Analog Output Enable Flag (analog output active if 1) */
	48	#define PCF8591_CONTROL_AOEF 0x40
fb4504fe JD	49
fb4504fe JD	50	/* Analog Input Programming
1da177e4 LT	51	0x00 = four single ended inputs
	52	0x10 = three differential inputs
	53	0x20 = single ended and differential mixed
	54	0x30 = two differential inputs */
	55	#define PCF8591_CONTROL_AIP_MASK 0x30
	56
	57	/* Autoincrement Flag (switch on if 1) */
	58	#define PCF8591_CONTROL_AINC 0x04
	59
	60	/* Channel selection
fb4504fe	61	0x00 = channel 0
1da177e4 LT	62	0x01 = channel 1
	63	0x02 = channel 2
	64	0x03 = channel 3 */
	65	#define PCF8591_CONTROL_AICH_MASK 0x03
	66
	67	/* Initial values */
	68	#define PCF8591_INIT_CONTROL ((input_mode << 4) \| PCF8591_CONTROL_AOEF)
	69	#define PCF8591_INIT_AOUT 0 /* DAC out = 0 */
	70
	71	/* Conversions */
	72	#define REG_TO_SIGNED(reg) (((reg) & 0x80)?((reg) - 256):(reg))
	73
	74	struct pcf8591_data {
5c085d36	75	struct mutex update_lock;
1da177e4 LT	76
	77	u8 control;
	78	u8 aout;
	79	};
	80
1da177e4 LT	81	static void pcf8591_init_client(struct i2c_client *client);
	82	static int pcf8591_read_channel(struct device *dev, int channel);
	83
1da177e4 LT	84	/* following are the sysfs callback functions */
1da177e4 LT	85	#define show_in_channel(channel) \
a5099cfc	86	static ssize_t show_in##channel##_input(struct device dev, struct device_attribute attr, char *buf) \
1da177e4 LT	87	{ \
	88	return sprintf(buf, "%d\n", pcf8591_read_channel(dev, channel));\
	89	} \
	90	static DEVICE_ATTR(in##channel##_input, S_IRUGO, \
	91	show_in##channel##_input, NULL);
	92
	93	show_in_channel(0);
	94	show_in_channel(1);
	95	show_in_channel(2);
	96	show_in_channel(3);
	97
a5099cfc	98	static ssize_t show_out0_ouput(struct device dev, struct device_attribute attr, char *buf)
1da177e4 LT	99	{
	100	struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
	101	return sprintf(buf, "%d\n", data->aout * 10);
	102	}
	103
a5099cfc	104	static ssize_t set_out0_output(struct device dev, struct device_attribute attr, const char *buf, size_t count)
1da177e4 LT	105	{
	106	unsigned int value;
	107	struct i2c_client *client = to_i2c_client(dev);
	108	struct pcf8591_data *data = i2c_get_clientdata(client);
	109	if ((value = (simple_strtoul(buf, NULL, 10) + 5) / 10) <= 255) {
	110	data->aout = value;
	111	i2c_smbus_write_byte_data(client, data->control, data->aout);
	112	return count;
	113	}
	114	return -EINVAL;
	115	}
	116
fb4504fe	117	static DEVICE_ATTR(out0_output, S_IWUSR \| S_IRUGO,
1da177e4 LT	118	show_out0_ouput, set_out0_output);
1da177e4 LT	119
a5099cfc	120	static ssize_t show_out0_enable(struct device dev, struct device_attribute attr, char *buf)
1da177e4 LT	121	{
	122	struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
	123	return sprintf(buf, "%u\n", !(!(data->control & PCF8591_CONTROL_AOEF)));
	124	}
	125
a5099cfc	126	static ssize_t set_out0_enable(struct device dev, struct device_attribute attr, const char *buf, size_t count)
1da177e4 LT	127	{
	128	struct i2c_client *client = to_i2c_client(dev);
	129	struct pcf8591_data *data = i2c_get_clientdata(client);
	130	unsigned long val = simple_strtoul(buf, NULL, 10);
	131
5c085d36	132	mutex_lock(&data->update_lock);
1da177e4 LT	133	if (val)
	134	data->control \|= PCF8591_CONTROL_AOEF;
	135	else
	136	data->control &= ~PCF8591_CONTROL_AOEF;
	137	i2c_smbus_write_byte(client, data->control);
5c085d36	138	mutex_unlock(&data->update_lock);
1da177e4 LT	139	return count;
	140	}
	141
fb4504fe	142	static DEVICE_ATTR(out0_enable, S_IWUSR \| S_IRUGO,
1da177e4 LT	143	show_out0_enable, set_out0_enable);
1da177e4 LT	144
7d9db67f JD	145	static struct attribute *pcf8591_attributes[] = {
	146	&dev_attr_out0_enable.attr,
	147	&dev_attr_out0_output.attr,
	148	&dev_attr_in0_input.attr,
	149	&dev_attr_in1_input.attr,
	150	NULL
	151	};
	152
	153	static const struct attribute_group pcf8591_attr_group = {
	154	.attrs = pcf8591_attributes,
	155	};
	156
	157	static struct attribute *pcf8591_attributes_opt[] = {
	158	&dev_attr_in2_input.attr,
	159	&dev_attr_in3_input.attr,
	160	NULL
	161	};
	162
	163	static const struct attribute_group pcf8591_attr_group_opt = {
	164	.attrs = pcf8591_attributes_opt,
	165	};
	166
1da177e4 LT	167	/*
	168	* Real code
	169	*/
1da177e4	170
8b77e6ac JD	171	/* Return 0 if detection is successful, -ENODEV otherwise */
	172	static int pcf8591_detect(struct i2c_client *client, int kind,
	173	struct i2c_board_info *info)
1da177e4	174	{
8b77e6ac	175	struct i2c_adapter *adapter = client->adapter;
1da177e4 LT	176
	177	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE
	178	\| I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
8b77e6ac JD	179	return -ENODEV;
	180
	181	/* Now, we would do the remaining detection. But the PCF8591 is plainly
	182	impossible to detect! Stupid chip. */
	183
	184	strlcpy(info->type, "pcf8591", I2C_NAME_SIZE);
	185
	186	return 0;
	187	}
	188
	189	static int pcf8591_probe(struct i2c_client *client,
	190	const struct i2c_device_id *id)
	191	{
	192	struct pcf8591_data *data;
	193	int err;
1da177e4	194
5263ebb5	195	if (!(data = kzalloc(sizeof(struct pcf8591_data), GFP_KERNEL))) {
1da177e4 LT	196	err = -ENOMEM;
	197	goto exit;
	198	}
fb4504fe	199
f741f673	200	i2c_set_clientdata(client, data);
5c085d36	201	mutex_init(&data->update_lock);
1da177e4	202
1da177e4	203	/* Initialize the PCF8591 chip */
f741f673	204	pcf8591_init_client(client);
1da177e4 LT	205
1da177e4 LT	206	/* Register sysfs hooks */
f741f673	207	err = sysfs_create_group(&client->dev.kobj, &pcf8591_attr_group);
7d9db67f	208	if (err)
8b77e6ac	209	goto exit_kfree;
1da177e4 LT	210
1da177e4 LT	211	/* Register input2 if not in "two differential inputs" mode */
7d9db67f	212	if (input_mode != 3) {
f741f673	213	if ((err = device_create_file(&client->dev,
7d9db67f JD	214	&dev_attr_in2_input)))
	215	goto exit_sysfs_remove;
	216	}
	217
1da177e4	218	/* Register input3 only in "four single ended inputs" mode */
7d9db67f	219	if (input_mode == 0) {
f741f673	220	if ((err = device_create_file(&client->dev,
7d9db67f JD	221	&dev_attr_in3_input)))
	222	goto exit_sysfs_remove;
	223	}
	224
1da177e4	225	return 0;
1da177e4	226
7d9db67f	227	exit_sysfs_remove:
f741f673 JD	228	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
f741f673 JD	229	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
1da177e4 LT	230	exit_kfree:
	231	kfree(data);
	232	exit:
	233	return err;
	234	}
	235
8b77e6ac	236	static int pcf8591_remove(struct i2c_client *client)
1da177e4	237	{
7d9db67f JD	238	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
7d9db67f JD	239	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
1da177e4 LT	240	kfree(i2c_get_clientdata(client));
	241	return 0;
	242	}
	243
	244	/* Called when we have found a new PCF8591. */
	245	static void pcf8591_init_client(struct i2c_client *client)
	246	{
	247	struct pcf8591_data *data = i2c_get_clientdata(client);
	248	data->control = PCF8591_INIT_CONTROL;
	249	data->aout = PCF8591_INIT_AOUT;
	250
	251	i2c_smbus_write_byte_data(client, data->control, data->aout);
fb4504fe JD	252
fb4504fe JD	253	/* The first byte transmitted contains the conversion code of the
1da177e4 LT	254	previous read cycle. FLUSH IT! */
	255	i2c_smbus_read_byte(client);
	256	}
	257
	258	static int pcf8591_read_channel(struct device *dev, int channel)
	259	{
	260	u8 value;
	261	struct i2c_client *client = to_i2c_client(dev);
	262	struct pcf8591_data *data = i2c_get_clientdata(client);
	263
5c085d36	264	mutex_lock(&data->update_lock);
1da177e4 LT	265
	266	if ((data->control & PCF8591_CONTROL_AICH_MASK) != channel) {
	267	data->control = (data->control & ~PCF8591_CONTROL_AICH_MASK)
	268	\| channel;
	269	i2c_smbus_write_byte(client, data->control);
fb4504fe JD	270
fb4504fe JD	271	/* The first byte transmitted contains the conversion code of
1da177e4 LT	272	the previous read cycle. FLUSH IT! */
	273	i2c_smbus_read_byte(client);
	274	}
	275	value = i2c_smbus_read_byte(client);
	276
5c085d36	277	mutex_unlock(&data->update_lock);
1da177e4 LT	278
	279	if ((channel == 2 && input_mode == 2) \|\|
	280	(channel != 3 && (input_mode == 1 \|\| input_mode == 3)))
	281	return (10 * REG_TO_SIGNED(value));
	282	else
	283	return (10 * value);
	284	}
	285
8b77e6ac JD	286	static const struct i2c_device_id pcf8591_id[] = {
	287	{ "pcf8591", 0 },
	288	{ }
	289	};
	290	MODULE_DEVICE_TABLE(i2c, pcf8591_id);
	291
	292	static struct i2c_driver pcf8591_driver = {
	293	.driver = {
	294	.name = "pcf8591",
	295	},
	296	.probe = pcf8591_probe,
	297	.remove = pcf8591_remove,
	298	.id_table = pcf8591_id,
	299
	300	.class = I2C_CLASS_HWMON, /* Nearest choice */
	301	.detect = pcf8591_detect,
	302	.address_data = &addr_data,
	303	};
	304
1da177e4 LT	305	static int __init pcf8591_init(void)
	306	{
	307	if (input_mode < 0 \|\| input_mode > 3) {
	308	printk(KERN_WARNING "pcf8591: invalid input_mode (%d)\n",
	309	input_mode);
	310	input_mode = 0;
	311	}
	312	return i2c_add_driver(&pcf8591_driver);
	313	}
	314
	315	static void __exit pcf8591_exit(void)
	316	{
	317	i2c_del_driver(&pcf8591_driver);
	318	}
	319
	320	MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
	321	MODULE_DESCRIPTION("PCF8591 driver");
	322	MODULE_LICENSE("GPL");
	323
	324	module_init(pcf8591_init);
	325	module_exit(pcf8591_exit);