[linux.git] / drivers / i2c / chips / eeprom.c

/*
    eeprom.c - Part of lm_sensors, Linux kernel modules for hardware
               monitoring
    Copyright (C) 1998, 1999  Frodo Looijaard <[email protected]> and
			       Philip Edelbrock <[email protected]>
    Copyright (C) 2003 Greg Kroah-Hartman <[email protected]>
    Copyright (C) 2003 IBM Corp.

    2004-01-16  Jean Delvare <[email protected]>
    Divide the eeprom in 32-byte (arbitrary) slices. This significantly
    speeds sensors up, as well as various scripts using the eeprom
    module.

    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/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/mutex.h>

/* Addresses to scan */
static unsigned short normal_i2c[] = { 0x50, 0x51, 0x52, 0x53, 0x54,
					0x55, 0x56, 0x57, I2C_CLIENT_END };

/* Insmod parameters */
I2C_CLIENT_INSMOD_1(eeprom);


/* Size of EEPROM in bytes */
#define EEPROM_SIZE		256

/* possible types of eeprom devices */
enum eeprom_nature {
	UNKNOWN,
	VAIO,
};

/* Each client has this additional data */
struct eeprom_data {
	struct i2c_client client;
	struct mutex update_lock;
	u8 valid;			/* bitfield, bit!=0 if slice is valid */
	unsigned long last_updated[8];	/* In jiffies, 8 slices */
	u8 data[EEPROM_SIZE];		/* Register values */
	enum eeprom_nature nature;
};


static int eeprom_attach_adapter(struct i2c_adapter *adapter);
static int eeprom_detect(struct i2c_adapter *adapter, int address, int kind);
static int eeprom_detach_client(struct i2c_client *client);

/* This is the driver that will be inserted */
static struct i2c_driver eeprom_driver = {
	.driver = {
		.name	= "eeprom",
	},
	.id		= I2C_DRIVERID_EEPROM,
	.attach_adapter	= eeprom_attach_adapter,
	.detach_client	= eeprom_detach_client,
};

static void eeprom_update_client(struct i2c_client *client, u8 slice)
{
	struct eeprom_data *data = i2c_get_clientdata(client);
	int i, j;

	mutex_lock(&data->update_lock);

	if (!(data->valid & (1 << slice)) ||
	    time_after(jiffies, data->last_updated[slice] + 300 * HZ)) {
		dev_dbg(&client->dev, "Starting eeprom update, slice %u\n", slice);

		if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
			for (i = slice << 5; i < (slice + 1) << 5; i += I2C_SMBUS_BLOCK_MAX)
				if (i2c_smbus_read_i2c_block_data(client, i, data->data + i) != I2C_SMBUS_BLOCK_MAX)
					goto exit;
		} else {
			if (i2c_smbus_write_byte(client, slice << 5)) {
				dev_dbg(&client->dev, "eeprom read start has failed!\n");
				goto exit;
			}
			for (i = slice << 5; i < (slice + 1) << 5; i++) {
				j = i2c_smbus_read_byte(client);
				if (j < 0)
					goto exit;
				data->data[i] = (u8) j;
			}
		}
		data->last_updated[slice] = jiffies;
		data->valid |= (1 << slice);
	}
exit:
	mutex_unlock(&data->update_lock);
}

static ssize_t eeprom_read(struct kobject *kobj, char *buf, loff_t off, size_t count)
{
	struct i2c_client *client = to_i2c_client(container_of(kobj, struct device, kobj));
	struct eeprom_data *data = i2c_get_clientdata(client);
	u8 slice;

	if (off > EEPROM_SIZE)
		return 0;
	if (off + count > EEPROM_SIZE)
		count = EEPROM_SIZE - off;

	/* Only refresh slices which contain requested bytes */
	for (slice = off >> 5; slice <= (off + count - 1) >> 5; slice++)
		eeprom_update_client(client, slice);

	/* Hide Vaio security settings to regular users (16 first bytes) */
	if (data->nature == VAIO && off < 16 && !capable(CAP_SYS_ADMIN)) {
		size_t in_row1 = 16 - off;
		in_row1 = min(in_row1, count);
		memset(buf, 0, in_row1);
		if (count - in_row1 > 0)
			memcpy(buf + in_row1, &data->data[16], count - in_row1);
	} else {
		memcpy(buf, &data->data[off], count);
	}

	return count;
}

static struct bin_attribute eeprom_attr = {
	.attr = {
		.name = "eeprom",
		.mode = S_IRUGO,
		.owner = THIS_MODULE,
	},
	.size = EEPROM_SIZE,
	.read = eeprom_read,
};

static int eeprom_attach_adapter(struct i2c_adapter *adapter)
{
	return i2c_probe(adapter, &addr_data, eeprom_detect);
}

/* This function is called by i2c_probe */
static int eeprom_detect(struct i2c_adapter *adapter, int address, int kind)
{
	struct i2c_client *new_client;
	struct eeprom_data *data;
	int err = 0;

	/* There are three ways we can read the EEPROM data:
	   (1) I2C block reads (faster, but unsupported by most adapters)
	   (2) Consecutive byte reads (100% overhead)
	   (3) Regular byte data reads (200% overhead)
	   The third method is not implemented by this driver because all
	   known adapters support at least the second. */
	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA
					    | I2C_FUNC_SMBUS_BYTE))
		goto exit;

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

	new_client = &data->client;
	memset(data->data, 0xff, EEPROM_SIZE);
	i2c_set_clientdata(new_client, data);
	new_client->addr = address;
	new_client->adapter = adapter;
	new_client->driver = &eeprom_driver;
	new_client->flags = 0;

	/* Fill in the remaining client fields */
	strlcpy(new_client->name, "eeprom", I2C_NAME_SIZE);
	data->valid = 0;
	mutex_init(&data->update_lock);
	data->nature = UNKNOWN;

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

	/* Detect the Vaio nature of EEPROMs.
	   We use the "PCG-" prefix as the signature. */
	if (address == 0x57) {
		if (i2c_smbus_read_byte_data(new_client, 0x80) == 'P'
		 && i2c_smbus_read_byte(new_client) == 'C'
		 && i2c_smbus_read_byte(new_client) == 'G'
		 && i2c_smbus_read_byte(new_client) == '-') {
			dev_info(&new_client->dev, "Vaio EEPROM detected, "
				"enabling password protection\n");
			data->nature = VAIO;
		}
	}

	/* create the sysfs eeprom file */
	err = sysfs_create_bin_file(&new_client->dev.kobj, &eeprom_attr);
	if (err)
		goto exit_detach;

	return 0;

exit_detach:
	i2c_detach_client(new_client);
exit_kfree:
	kfree(data);
exit:
	return err;
}

static int eeprom_detach_client(struct i2c_client *client)
{
	int err;

	sysfs_remove_bin_file(&client->dev.kobj, &eeprom_attr);

	err = i2c_detach_client(client);
	if (err)
		return err;

	kfree(i2c_get_clientdata(client));

	return 0;
}

static int __init eeprom_init(void)
{
	return i2c_add_driver(&eeprom_driver);
}

static void __exit eeprom_exit(void)
{
	i2c_del_driver(&eeprom_driver);
}


MODULE_AUTHOR("Frodo Looijaard <[email protected]> and "
		"Philip Edelbrock <[email protected]> and "
		"Greg Kroah-Hartman <[email protected]>");
MODULE_DESCRIPTION("I2C EEPROM driver");
MODULE_LICENSE("GPL");

module_init(eeprom_init);
module_exit(eeprom_exit);
Commit	Line	Data
1da177e4 LT	1	/*
	2	eeprom.c - Part of lm_sensors, Linux kernel modules for hardware
	3	monitoring
	4	Copyright (C) 1998, 1999 Frodo Looijaard <[email protected]> and
	5	Philip Edelbrock <[email protected]>
	6	Copyright (C) 2003 Greg Kroah-Hartman <[email protected]>
	7	Copyright (C) 2003 IBM Corp.
	8
	9	2004-01-16 Jean Delvare <[email protected]>
	10	Divide the eeprom in 32-byte (arbitrary) slices. This significantly
	11	speeds sensors up, as well as various scripts using the eeprom
	12	module.
	13
	14	This program is free software; you can redistribute it and/or modify
	15	it under the terms of the GNU General Public License as published by
	16	the Free Software Foundation; either version 2 of the License, or
	17	(at your option) any later version.
	18
	19	This program is distributed in the hope that it will be useful,
	20	but WITHOUT ANY WARRANTY; without even the implied warranty of
	21	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	22	GNU General Public License for more details.
	23
	24	You should have received a copy of the GNU General Public License
	25	along with this program; if not, write to the Free Software
	26	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	27	*/
	28
1da177e4 LT	29	#include <linux/kernel.h>
	30	#include <linux/init.h>
	31	#include <linux/module.h>
	32	#include <linux/slab.h>
1da177e4 LT	33	#include <linux/jiffies.h>
1da177e4 LT	34	#include <linux/i2c.h>
5c085d36	35	#include <linux/mutex.h>
1da177e4 LT	36
	37	/* Addresses to scan */
	38	static unsigned short normal_i2c[] = { 0x50, 0x51, 0x52, 0x53, 0x54,
	39	0x55, 0x56, 0x57, I2C_CLIENT_END };
1da177e4 LT	40
1da177e4 LT	41	/* Insmod parameters */
f4b50261	42	I2C_CLIENT_INSMOD_1(eeprom);
1da177e4 LT	43
	44
	45	/* Size of EEPROM in bytes */
	46	#define EEPROM_SIZE 256
	47
	48	/* possible types of eeprom devices */
	49	enum eeprom_nature {
	50	UNKNOWN,
	51	VAIO,
	52	};
	53
	54	/* Each client has this additional data */
	55	struct eeprom_data {
	56	struct i2c_client client;
5c085d36	57	struct mutex update_lock;
1da177e4 LT	58	u8 valid; /* bitfield, bit!=0 if slice is valid */
	59	unsigned long last_updated[8]; /* In jiffies, 8 slices */
	60	u8 data[EEPROM_SIZE]; /* Register values */
	61	enum eeprom_nature nature;
	62	};
	63
	64
	65	static int eeprom_attach_adapter(struct i2c_adapter *adapter);
	66	static int eeprom_detect(struct i2c_adapter *adapter, int address, int kind);
	67	static int eeprom_detach_client(struct i2c_client *client);
	68
	69	/* This is the driver that will be inserted */
	70	static struct i2c_driver eeprom_driver = {
a9718b0c	71	.driver = {
a9718b0c LR	72	.name = "eeprom",
a9718b0c LR	73	},
1da177e4	74	.id = I2C_DRIVERID_EEPROM,
1da177e4 LT	75	.attach_adapter = eeprom_attach_adapter,
	76	.detach_client = eeprom_detach_client,
	77	};
	78
	79	static void eeprom_update_client(struct i2c_client *client, u8 slice)
	80	{
	81	struct eeprom_data *data = i2c_get_clientdata(client);
	82	int i, j;
	83
5c085d36	84	mutex_lock(&data->update_lock);
1da177e4 LT	85
	86	if (!(data->valid & (1 << slice)) \|\|
	87	time_after(jiffies, data->last_updated[slice] + 300 * HZ)) {
	88	dev_dbg(&client->dev, "Starting eeprom update, slice %u\n", slice);
	89
	90	if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
30dac746 JD	91	for (i = slice << 5; i < (slice + 1) << 5; i += I2C_SMBUS_BLOCK_MAX)
30dac746 JD	92	if (i2c_smbus_read_i2c_block_data(client, i, data->data + i) != I2C_SMBUS_BLOCK_MAX)
1da177e4 LT	93	goto exit;
	94	} else {
	95	if (i2c_smbus_write_byte(client, slice << 5)) {
	96	dev_dbg(&client->dev, "eeprom read start has failed!\n");
	97	goto exit;
	98	}
	99	for (i = slice << 5; i < (slice + 1) << 5; i++) {
	100	j = i2c_smbus_read_byte(client);
	101	if (j < 0)
	102	goto exit;
	103	data->data[i] = (u8) j;
	104	}
	105	}
	106	data->last_updated[slice] = jiffies;
	107	data->valid \|= (1 << slice);
	108	}
	109	exit:
5c085d36	110	mutex_unlock(&data->update_lock);
1da177e4 LT	111	}
	112
	113	static ssize_t eeprom_read(struct kobject kobj, char buf, loff_t off, size_t count)
	114	{
	115	struct i2c_client *client = to_i2c_client(container_of(kobj, struct device, kobj));
	116	struct eeprom_data *data = i2c_get_clientdata(client);
	117	u8 slice;
	118
	119	if (off > EEPROM_SIZE)
	120	return 0;
	121	if (off + count > EEPROM_SIZE)
	122	count = EEPROM_SIZE - off;
	123
	124	/* Only refresh slices which contain requested bytes */
	125	for (slice = off >> 5; slice <= (off + count - 1) >> 5; slice++)
	126	eeprom_update_client(client, slice);
	127
	128	/* Hide Vaio security settings to regular users (16 first bytes) */
	129	if (data->nature == VAIO && off < 16 && !capable(CAP_SYS_ADMIN)) {
	130	size_t in_row1 = 16 - off;
	131	in_row1 = min(in_row1, count);
	132	memset(buf, 0, in_row1);
	133	if (count - in_row1 > 0)
	134	memcpy(buf + in_row1, &data->data[16], count - in_row1);
	135	} else {
	136	memcpy(buf, &data->data[off], count);
	137	}
	138
	139	return count;
	140	}
	141
	142	static struct bin_attribute eeprom_attr = {
	143	.attr = {
	144	.name = "eeprom",
	145	.mode = S_IRUGO,
	146	.owner = THIS_MODULE,
	147	},
	148	.size = EEPROM_SIZE,
	149	.read = eeprom_read,
	150	};
	151
	152	static int eeprom_attach_adapter(struct i2c_adapter *adapter)
	153	{
2ed2dc3c	154	return i2c_probe(adapter, &addr_data, eeprom_detect);
1da177e4 LT	155	}
1da177e4 LT	156
2ed2dc3c	157	/* This function is called by i2c_probe */
6536c49a	158	static int eeprom_detect(struct i2c_adapter *adapter, int address, int kind)
1da177e4 LT	159	{
	160	struct i2c_client *new_client;
	161	struct eeprom_data *data;
	162	int err = 0;
	163
	164	/* There are three ways we can read the EEPROM data:
	165	(1) I2C block reads (faster, but unsupported by most adapters)
	166	(2) Consecutive byte reads (100% overhead)
	167	(3) Regular byte data reads (200% overhead)
	168	The third method is not implemented by this driver because all
	169	known adapters support at least the second. */
	170	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA
	171	\| I2C_FUNC_SMBUS_BYTE))
	172	goto exit;
	173
5263ebb5	174	if (!(data = kzalloc(sizeof(struct eeprom_data), GFP_KERNEL))) {
1da177e4 LT	175	err = -ENOMEM;
	176	goto exit;
	177	}
1da177e4 LT	178
	179	new_client = &data->client;
	180	memset(data->data, 0xff, EEPROM_SIZE);
	181	i2c_set_clientdata(new_client, data);
	182	new_client->addr = address;
	183	new_client->adapter = adapter;
	184	new_client->driver = &eeprom_driver;
	185	new_client->flags = 0;
	186
1da177e4 LT	187	/* Fill in the remaining client fields */
	188	strlcpy(new_client->name, "eeprom", I2C_NAME_SIZE);
	189	data->valid = 0;
5c085d36	190	mutex_init(&data->update_lock);
1da177e4 LT	191	data->nature = UNKNOWN;
	192
	193	/* Tell the I2C layer a new client has arrived */
	194	if ((err = i2c_attach_client(new_client)))
	195	goto exit_kfree;
	196
	197	/* Detect the Vaio nature of EEPROMs.
	198	We use the "PCG-" prefix as the signature. */
	199	if (address == 0x57) {
	200	if (i2c_smbus_read_byte_data(new_client, 0x80) == 'P'
	201	&& i2c_smbus_read_byte(new_client) == 'C'
	202	&& i2c_smbus_read_byte(new_client) == 'G'
	203	&& i2c_smbus_read_byte(new_client) == '-') {
	204	dev_info(&new_client->dev, "Vaio EEPROM detected, "
	205	"enabling password protection\n");
	206	data->nature = VAIO;
	207	}
	208	}
	209
	210	/* create the sysfs eeprom file */
7d9db67f JD	211	err = sysfs_create_bin_file(&new_client->dev.kobj, &eeprom_attr);
	212	if (err)
	213	goto exit_detach;
1da177e4 LT	214
	215	return 0;
	216
7d9db67f JD	217	exit_detach:
7d9db67f JD	218	i2c_detach_client(new_client);
1da177e4 LT	219	exit_kfree:
	220	kfree(data);
	221	exit:
	222	return err;
	223	}
	224
	225	static int eeprom_detach_client(struct i2c_client *client)
	226	{
	227	int err;
	228
7d9db67f JD	229	sysfs_remove_bin_file(&client->dev.kobj, &eeprom_attr);
7d9db67f JD	230
1da177e4	231	err = i2c_detach_client(client);
7bef5594	232	if (err)
1da177e4	233	return err;
1da177e4 LT	234
	235	kfree(i2c_get_clientdata(client));
	236
	237	return 0;
	238	}
	239
	240	static int __init eeprom_init(void)
	241	{
	242	return i2c_add_driver(&eeprom_driver);
	243	}
	244
	245	static void __exit eeprom_exit(void)
	246	{
	247	i2c_del_driver(&eeprom_driver);
	248	}
	249
	250
	251	MODULE_AUTHOR("Frodo Looijaard <[email protected]> and "
	252	"Philip Edelbrock <[email protected]> and "
	253	"Greg Kroah-Hartman <[email protected]>");
	254	MODULE_DESCRIPTION("I2C EEPROM driver");
	255	MODULE_LICENSE("GPL");
	256
	257	module_init(eeprom_init);
	258	module_exit(eeprom_exit);