[deliverable/linux.git] / drivers / misc / eeprom / eeprom.c

/*
 * Copyright (C) 1998, 1999  Frodo Looijaard <frodol@dds.nl> and
 *                           Philip Edelbrock <phil@netroedge.com>
 * Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
 * Copyright (C) 2003 IBM Corp.
 * Copyright (C) 2004 Jean Delvare <jdelvare@suse.de>
 *
 * 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/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/mutex.h>

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


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

	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 += 32)
				if (i2c_smbus_read_i2c_block_data(client, i,
							32, data->data + i)
							!= 32)
					goto exit;
		} else {
			for (i = slice << 5; i < (slice + 1) << 5; i += 2) {
				int word = i2c_smbus_read_word_data(client, i);
				if (word < 0)
					goto exit;
				data->data[i] = word & 0xff;
				data->data[i + 1] = word >> 8;
			}
		}
		data->last_updated[slice] = jiffies;
		data->valid |= (1 << slice);
	}
exit:
	mutex_unlock(&data->update_lock);
}

static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
			   struct bin_attribute *bin_attr,
			   char *buf, loff_t off, size_t count)
{
	struct i2c_client *client = to_i2c_client(kobj_to_dev(kobj));
	struct eeprom_data *data = i2c_get_clientdata(client);
	u8 slice;

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

	/* Hide Vaio private settings to regular users:
	   - BIOS passwords: bytes 0x00 to 0x0f
	   - UUID: bytes 0x10 to 0x1f
	   - Serial number: 0xc0 to 0xdf */
	if (data->nature == VAIO && !capable(CAP_SYS_ADMIN)) {
		int i;

		for (i = 0; i < count; i++) {
			if ((off + i <= 0x1f) ||
			    (off + i >= 0xc0 && off + i <= 0xdf))
				buf[i] = 0;
			else
				buf[i] = data->data[off + i];
		}
	} else {
		memcpy(buf, &data->data[off], count);
	}

	return count;
}

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

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

	/* EDID EEPROMs are often 24C00 EEPROMs, which answer to all
	   addresses 0x50-0x57, but we only care about 0x50. So decline
	   attaching to addresses >= 0x51 on DDC buses */
	if (!(adapter->class & I2C_CLASS_SPD) && client->addr >= 0x51)
		return -ENODEV;

	/* There are four ways we can read the EEPROM data:
	   (1) I2C block reads (faster, but unsupported by most adapters)
	   (2) Word reads (128% overhead)
	   (3) Consecutive byte reads (88% overhead, unsafe)
	   (4) Regular byte data reads (265% overhead)
	   The third and fourth methods are not implemented by this driver
	   because all known adapters support one of the first two. */
	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)
	 && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
		return -ENODEV;

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

	return 0;
}

static int eeprom_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct i2c_adapter *adapter = client->adapter;
	struct eeprom_data *data;

	data = devm_kzalloc(&client->dev, sizeof(struct eeprom_data),
			    GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	memset(data->data, 0xff, EEPROM_SIZE);
	i2c_set_clientdata(client, data);
	mutex_init(&data->update_lock);
	data->nature = UNKNOWN;

	/* Detect the Vaio nature of EEPROMs.
	   We use the "PCG-" or "VGN-" prefix as the signature. */
	if (client->addr == 0x57
	 && i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
		char name[4];

		name[0] = i2c_smbus_read_byte_data(client, 0x80);
		name[1] = i2c_smbus_read_byte_data(client, 0x81);
		name[2] = i2c_smbus_read_byte_data(client, 0x82);
		name[3] = i2c_smbus_read_byte_data(client, 0x83);

		if (!memcmp(name, "PCG-", 4) || !memcmp(name, "VGN-", 4)) {
			dev_info(&client->dev, "Vaio EEPROM detected, "
				 "enabling privacy protection\n");
			data->nature = VAIO;
		}
	}

	/* create the sysfs eeprom file */
	return sysfs_create_bin_file(&client->dev.kobj, &eeprom_attr);
}

static int eeprom_remove(struct i2c_client *client)
{
	sysfs_remove_bin_file(&client->dev.kobj, &eeprom_attr);

	return 0;
}

static const struct i2c_device_id eeprom_id[] = {
	{ "eeprom", 0 },
	{ }
};

static struct i2c_driver eeprom_driver = {
	.driver = {
		.name	= "eeprom",
	},
	.probe		= eeprom_probe,
	.remove		= eeprom_remove,
	.id_table	= eeprom_id,

	.class		= I2C_CLASS_DDC | I2C_CLASS_SPD,
	.detect		= eeprom_detect,
	.address_list	= normal_i2c,
};

module_i2c_driver(eeprom_driver);

MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
		"Philip Edelbrock <phil@netroedge.com> and "
		"Greg Kroah-Hartman <greg@kroah.com>");
MODULE_DESCRIPTION("I2C EEPROM driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4	1	/*
110f4229 AA	2	* Copyright (C) 1998, 1999 Frodo Looijaard <frodol@dds.nl> and
	3	* Philip Edelbrock <phil@netroedge.com>
	4	* Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
	5	* Copyright (C) 2003 IBM Corp.
7c81c60f	6	* Copyright (C) 2004 Jean Delvare <jdelvare@suse.de>
110f4229 AA	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License as published by
	10	* the Free Software Foundation; either version 2 of the License, or
	11	* (at your option) any later version.
	12	*
	13	* This program is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	* GNU General Public License for more details.
	17	*/
1da177e4	18
1da177e4	19	#include <linux/kernel.h>
1da177e4	20	#include <linux/module.h>
1698da24	21	#include <linux/device.h>
1da177e4 LT	22	#include <linux/jiffies.h>
1da177e4 LT	23	#include <linux/i2c.h>
5c085d36	24	#include <linux/mutex.h>
1da177e4 LT	25
1da177e4 LT	26	/* Addresses to scan */
2cdddeb8	27	static const unsigned short normal_i2c[] = { 0x50, 0x51, 0x52, 0x53, 0x54,
1da177e4	28	0x55, 0x56, 0x57, I2C_CLIENT_END };
1da177e4	29
1da177e4 LT	30
	31	/* Size of EEPROM in bytes */
	32	#define EEPROM_SIZE 256
	33
	34	/* possible types of eeprom devices */
	35	enum eeprom_nature {
	36	UNKNOWN,
	37	VAIO,
	38	};
	39
	40	/* Each client has this additional data */
	41	struct eeprom_data {
5c085d36	42	struct mutex update_lock;
1da177e4 LT	43	u8 valid; /* bitfield, bit!=0 if slice is valid */
	44	unsigned long last_updated[8]; /* In jiffies, 8 slices */
	45	u8 data[EEPROM_SIZE]; /* Register values */
	46	enum eeprom_nature nature;
	47	};
	48
	49
1da177e4 LT	50	static void eeprom_update_client(struct i2c_client *client, u8 slice)
	51	{
	52	struct eeprom_data *data = i2c_get_clientdata(client);
1b4dff9c	53	int i;
1da177e4	54
5c085d36	55	mutex_lock(&data->update_lock);
1da177e4 LT	56
	57	if (!(data->valid & (1 << slice)) \|\|
	58	time_after(jiffies, data->last_updated[slice] + 300 * HZ)) {
	59	dev_dbg(&client->dev, "Starting eeprom update, slice %u\n", slice);
	60
	61	if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
4b2643d7 JD	62	for (i = slice << 5; i < (slice + 1) << 5; i += 32)
	63	if (i2c_smbus_read_i2c_block_data(client, i,
	64	32, data->data + i)
	65	!= 32)
1da177e4 LT	66	goto exit;
1da177e4 LT	67	} else {
1b4dff9c JD	68	for (i = slice << 5; i < (slice + 1) << 5; i += 2) {
	69	int word = i2c_smbus_read_word_data(client, i);
	70	if (word < 0)
1da177e4	71	goto exit;
1b4dff9c JD	72	data->data[i] = word & 0xff;
1b4dff9c JD	73	data->data[i + 1] = word >> 8;
1da177e4 LT	74	}
	75	}
	76	data->last_updated[slice] = jiffies;
	77	data->valid \|= (1 << slice);
	78	}
	79	exit:
5c085d36	80	mutex_unlock(&data->update_lock);
1da177e4 LT	81	}
1da177e4 LT	82
2c3c8bea CW	83	static ssize_t eeprom_read(struct file filp, struct kobject kobj,
2c3c8bea CW	84	struct bin_attribute *bin_attr,
91a69029	85	char *buf, loff_t off, size_t count)
1da177e4	86	{
092462c2	87	struct i2c_client *client = to_i2c_client(kobj_to_dev(kobj));
1da177e4 LT	88	struct eeprom_data *data = i2c_get_clientdata(client);
	89	u8 slice;
	90
1da177e4 LT	91	/* Only refresh slices which contain requested bytes */
	92	for (slice = off >> 5; slice <= (off + count - 1) >> 5; slice++)
	93	eeprom_update_client(client, slice);
	94
0f2cbd38 JD	95	/* Hide Vaio private settings to regular users:
	96	- BIOS passwords: bytes 0x00 to 0x0f
	97	- UUID: bytes 0x10 to 0x1f
	98	- Serial number: 0xc0 to 0xdf */
	99	if (data->nature == VAIO && !capable(CAP_SYS_ADMIN)) {
	100	int i;
	101
	102	for (i = 0; i < count; i++) {
	103	if ((off + i <= 0x1f) \|\|
	104	(off + i >= 0xc0 && off + i <= 0xdf))
	105	buf[i] = 0;
	106	else
	107	buf[i] = data->data[off + i];
	108	}
1da177e4 LT	109	} else {
	110	memcpy(buf, &data->data[off], count);
	111	}
	112
	113	return count;
	114	}
	115
	116	static struct bin_attribute eeprom_attr = {
	117	.attr = {
	118	.name = "eeprom",
	119	.mode = S_IRUGO,
1da177e4 LT	120	},
	121	.size = EEPROM_SIZE,
	122	.read = eeprom_read,
	123	};
	124
68be3363	125	/* Return 0 if detection is successful, -ENODEV otherwise */
310ec792	126	static int eeprom_detect(struct i2c_client client, struct i2c_board_info info)
1da177e4	127	{
68be3363	128	struct i2c_adapter *adapter = client->adapter;
1da177e4	129
d4653bf9 JD	130	/* EDID EEPROMs are often 24C00 EEPROMs, which answer to all
	131	addresses 0x50-0x57, but we only care about 0x50. So decline
	132	attaching to addresses >= 0x51 on DDC buses */
68be3363 JD	133	if (!(adapter->class & I2C_CLASS_SPD) && client->addr >= 0x51)
68be3363 JD	134	return -ENODEV;
d4653bf9	135
1b4dff9c	136	/* There are four ways we can read the EEPROM data:
1da177e4	137	(1) I2C block reads (faster, but unsupported by most adapters)
1b4dff9c JD	138	(2) Word reads (128% overhead)
	139	(3) Consecutive byte reads (88% overhead, unsafe)
	140	(4) Regular byte data reads (265% overhead)
	141	The third and fourth methods are not implemented by this driver
	142	because all known adapters support one of the first two. */
	143	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)
	144	&& !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
68be3363 JD	145	return -ENODEV;
	146
	147	strlcpy(info->type, "eeprom", I2C_NAME_SIZE);
	148
	149	return 0;
	150	}
	151
	152	static int eeprom_probe(struct i2c_client *client,
	153	const struct i2c_device_id *id)
	154	{
	155	struct i2c_adapter *adapter = client->adapter;
	156	struct eeprom_data *data;
1da177e4	157
1698da24 HS	158	data = devm_kzalloc(&client->dev, sizeof(struct eeprom_data),
	159	GFP_KERNEL);
	160	if (!data)
	161	return -ENOMEM;
1da177e4	162
1da177e4	163	memset(data->data, 0xff, EEPROM_SIZE);
f741f673	164	i2c_set_clientdata(client, data);
5c085d36	165	mutex_init(&data->update_lock);
1da177e4 LT	166	data->nature = UNKNOWN;
1da177e4 LT	167
1da177e4	168	/* Detect the Vaio nature of EEPROMs.
8b925a3d	169	We use the "PCG-" or "VGN-" prefix as the signature. */
68be3363	170	if (client->addr == 0x57
1b4dff9c	171	&& i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
8b925a3d JD	172	char name[4];
8b925a3d JD	173
f741f673 JD	174	name[0] = i2c_smbus_read_byte_data(client, 0x80);
	175	name[1] = i2c_smbus_read_byte_data(client, 0x81);
	176	name[2] = i2c_smbus_read_byte_data(client, 0x82);
	177	name[3] = i2c_smbus_read_byte_data(client, 0x83);
8b925a3d JD	178
8b925a3d JD	179	if (!memcmp(name, "PCG-", 4) \|\| !memcmp(name, "VGN-", 4)) {
f741f673	180	dev_info(&client->dev, "Vaio EEPROM detected, "
0f2cbd38	181	"enabling privacy protection\n");
1da177e4 LT	182	data->nature = VAIO;
	183	}
	184	}
	185
	186	/* create the sysfs eeprom file */
1698da24	187	return sysfs_create_bin_file(&client->dev.kobj, &eeprom_attr);
1da177e4 LT	188	}
1da177e4 LT	189
68be3363	190	static int eeprom_remove(struct i2c_client *client)
1da177e4	191	{
7d9db67f	192	sysfs_remove_bin_file(&client->dev.kobj, &eeprom_attr);
1da177e4 LT	193
	194	return 0;
	195	}
	196
68be3363 JD	197	static const struct i2c_device_id eeprom_id[] = {
	198	{ "eeprom", 0 },
	199	{ }
	200	};
	201
	202	static struct i2c_driver eeprom_driver = {
	203	.driver = {
	204	.name = "eeprom",
	205	},
	206	.probe = eeprom_probe,
	207	.remove = eeprom_remove,
	208	.id_table = eeprom_id,
	209
	210	.class = I2C_CLASS_DDC \| I2C_CLASS_SPD,
	211	.detect = eeprom_detect,
c3813d6a	212	.address_list = normal_i2c,
68be3363 JD	213	};
68be3363 JD	214
a64fe2ed	215	module_i2c_driver(eeprom_driver);
1da177e4 LT	216
	217	MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
	218	"Philip Edelbrock <phil@netroedge.com> and "
	219	"Greg Kroah-Hartman <greg@kroah.com>");
	220	MODULE_DESCRIPTION("I2C EEPROM driver");
	221	MODULE_LICENSE("GPL");