[mirror_ubuntu-bionic-kernel.git] / drivers / i2c / chips / 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 <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/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 const 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",
	},
	.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;

	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 kobject *kobj, struct bin_attribute *bin_attr,
			   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 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,
};

static int eeprom_attach_adapter(struct i2c_adapter *adapter)
{
	if (!(adapter->class & (I2C_CLASS_DDC | I2C_CLASS_SPD)))
		return 0;
	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 *client;
	struct eeprom_data *data;
	int err = 0;

	/* 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) && address >= 0x51)
		goto exit;

	/* 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))
		goto exit;

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

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

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

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

	/* Detect the Vaio nature of EEPROMs.
	   We use the "PCG-" or "VGN-" prefix as the signature. */
	if (address == 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 */
	err = sysfs_create_bin_file(&client->dev.kobj, &eeprom_attr);
	if (err)
		goto exit_detach;

	return 0;

exit_detach:
	i2c_detach_client(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 <frodol@dds.nl> and "
		"Philip Edelbrock <phil@netroedge.com> and "
		"Greg Kroah-Hartman <greg@kroah.com>");
MODULE_DESCRIPTION("I2C EEPROM driver");
MODULE_LICENSE("GPL");

module_init(eeprom_init);
module_exit(eeprom_exit);
Commit	Line	Data
1da177e4	1	/*
1da177e4 LT	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.
954a9930	6	Copyright (C) 2004 Jean Delvare <khali@linux-fr.org>
1da177e4 LT	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
	18	You should have received a copy of the GNU General Public License
	19	along with this program; if not, write to the Free Software
	20	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	21	*/
	22
1da177e4 LT	23	#include <linux/kernel.h>
	24	#include <linux/init.h>
	25	#include <linux/module.h>
	26	#include <linux/slab.h>
1da177e4 LT	27	#include <linux/jiffies.h>
1da177e4 LT	28	#include <linux/i2c.h>
5c085d36	29	#include <linux/mutex.h>
1da177e4 LT	30
1da177e4 LT	31	/* Addresses to scan */
2cdddeb8	32	static const unsigned short normal_i2c[] = { 0x50, 0x51, 0x52, 0x53, 0x54,
1da177e4	33	0x55, 0x56, 0x57, I2C_CLIENT_END };
1da177e4 LT	34
1da177e4 LT	35	/* Insmod parameters */
f4b50261	36	I2C_CLIENT_INSMOD_1(eeprom);
1da177e4 LT	37
	38
	39	/* Size of EEPROM in bytes */
	40	#define EEPROM_SIZE 256
	41
	42	/* possible types of eeprom devices */
	43	enum eeprom_nature {
	44	UNKNOWN,
	45	VAIO,
	46	};
	47
	48	/* Each client has this additional data */
	49	struct eeprom_data {
	50	struct i2c_client client;
5c085d36	51	struct mutex update_lock;
1da177e4 LT	52	u8 valid; /* bitfield, bit!=0 if slice is valid */
	53	unsigned long last_updated[8]; /* In jiffies, 8 slices */
	54	u8 data[EEPROM_SIZE]; /* Register values */
	55	enum eeprom_nature nature;
	56	};
	57
	58
	59	static int eeprom_attach_adapter(struct i2c_adapter *adapter);
	60	static int eeprom_detect(struct i2c_adapter *adapter, int address, int kind);
	61	static int eeprom_detach_client(struct i2c_client *client);
	62
	63	/* This is the driver that will be inserted */
	64	static struct i2c_driver eeprom_driver = {
a9718b0c	65	.driver = {
a9718b0c LR	66	.name = "eeprom",
a9718b0c LR	67	},
1da177e4 LT	68	.attach_adapter = eeprom_attach_adapter,
	69	.detach_client = eeprom_detach_client,
	70	};
	71
	72	static void eeprom_update_client(struct i2c_client *client, u8 slice)
	73	{
	74	struct eeprom_data *data = i2c_get_clientdata(client);
1b4dff9c	75	int i;
1da177e4	76
5c085d36	77	mutex_lock(&data->update_lock);
1da177e4 LT	78
	79	if (!(data->valid & (1 << slice)) \|\|
	80	time_after(jiffies, data->last_updated[slice] + 300 * HZ)) {
	81	dev_dbg(&client->dev, "Starting eeprom update, slice %u\n", slice);
	82
	83	if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
4b2643d7 JD	84	for (i = slice << 5; i < (slice + 1) << 5; i += 32)
	85	if (i2c_smbus_read_i2c_block_data(client, i,
	86	32, data->data + i)
	87	!= 32)
1da177e4 LT	88	goto exit;
1da177e4 LT	89	} else {
1b4dff9c JD	90	for (i = slice << 5; i < (slice + 1) << 5; i += 2) {
	91	int word = i2c_smbus_read_word_data(client, i);
	92	if (word < 0)
1da177e4	93	goto exit;
1b4dff9c JD	94	data->data[i] = word & 0xff;
1b4dff9c JD	95	data->data[i + 1] = word >> 8;
1da177e4 LT	96	}
	97	}
	98	data->last_updated[slice] = jiffies;
	99	data->valid \|= (1 << slice);
	100	}
	101	exit:
5c085d36	102	mutex_unlock(&data->update_lock);
1da177e4 LT	103	}
1da177e4 LT	104
91a69029 ZR	105	static ssize_t eeprom_read(struct kobject kobj, struct bin_attribute bin_attr,
91a69029 ZR	106	char *buf, loff_t off, size_t count)
1da177e4 LT	107	{
	108	struct i2c_client *client = to_i2c_client(container_of(kobj, struct device, kobj));
	109	struct eeprom_data *data = i2c_get_clientdata(client);
	110	u8 slice;
	111
	112	if (off > EEPROM_SIZE)
	113	return 0;
	114	if (off + count > EEPROM_SIZE)
	115	count = EEPROM_SIZE - off;
	116
	117	/* Only refresh slices which contain requested bytes */
	118	for (slice = off >> 5; slice <= (off + count - 1) >> 5; slice++)
	119	eeprom_update_client(client, slice);
	120
0f2cbd38 JD	121	/* Hide Vaio private settings to regular users:
	122	- BIOS passwords: bytes 0x00 to 0x0f
	123	- UUID: bytes 0x10 to 0x1f
	124	- Serial number: 0xc0 to 0xdf */
	125	if (data->nature == VAIO && !capable(CAP_SYS_ADMIN)) {
	126	int i;
	127
	128	for (i = 0; i < count; i++) {
	129	if ((off + i <= 0x1f) \|\|
	130	(off + i >= 0xc0 && off + i <= 0xdf))
	131	buf[i] = 0;
	132	else
	133	buf[i] = data->data[off + i];
	134	}
1da177e4 LT	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,
1da177e4 LT	146	},
	147	.size = EEPROM_SIZE,
	148	.read = eeprom_read,
	149	};
	150
	151	static int eeprom_attach_adapter(struct i2c_adapter *adapter)
	152	{
d4653bf9 JD	153	if (!(adapter->class & (I2C_CLASS_DDC \| I2C_CLASS_SPD)))
d4653bf9 JD	154	return 0;
2ed2dc3c	155	return i2c_probe(adapter, &addr_data, eeprom_detect);
1da177e4 LT	156	}
1da177e4 LT	157
2ed2dc3c	158	/* This function is called by i2c_probe */
6536c49a	159	static int eeprom_detect(struct i2c_adapter *adapter, int address, int kind)
1da177e4	160	{
f741f673	161	struct i2c_client *client;
1da177e4 LT	162	struct eeprom_data *data;
	163	int err = 0;
	164
d4653bf9 JD	165	/* EDID EEPROMs are often 24C00 EEPROMs, which answer to all
	166	addresses 0x50-0x57, but we only care about 0x50. So decline
	167	attaching to addresses >= 0x51 on DDC buses */
	168	if (!(adapter->class & I2C_CLASS_SPD) && address >= 0x51)
	169	goto exit;
	170
1b4dff9c	171	/* There are four ways we can read the EEPROM data:
1da177e4	172	(1) I2C block reads (faster, but unsupported by most adapters)
1b4dff9c JD	173	(2) Word reads (128% overhead)
	174	(3) Consecutive byte reads (88% overhead, unsafe)
	175	(4) Regular byte data reads (265% overhead)
	176	The third and fourth methods are not implemented by this driver
	177	because all known adapters support one of the first two. */
	178	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)
	179	&& !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
1da177e4 LT	180	goto exit;
1da177e4 LT	181
5263ebb5	182	if (!(data = kzalloc(sizeof(struct eeprom_data), GFP_KERNEL))) {
1da177e4 LT	183	err = -ENOMEM;
	184	goto exit;
	185	}
1da177e4	186
f741f673	187	client = &data->client;
1da177e4	188	memset(data->data, 0xff, EEPROM_SIZE);
f741f673 JD	189	i2c_set_clientdata(client, data);
	190	client->addr = address;
	191	client->adapter = adapter;
	192	client->driver = &eeprom_driver;
1da177e4	193
1da177e4	194	/* Fill in the remaining client fields */
f741f673	195	strlcpy(client->name, "eeprom", I2C_NAME_SIZE);
5c085d36	196	mutex_init(&data->update_lock);
1da177e4 LT	197	data->nature = UNKNOWN;
	198
	199	/* Tell the I2C layer a new client has arrived */
f741f673	200	if ((err = i2c_attach_client(client)))
1da177e4 LT	201	goto exit_kfree;
	202
	203	/* Detect the Vaio nature of EEPROMs.
8b925a3d	204	We use the "PCG-" or "VGN-" prefix as the signature. */
1b4dff9c JD	205	if (address == 0x57
1b4dff9c JD	206	&& i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
8b925a3d JD	207	char name[4];
8b925a3d JD	208
f741f673 JD	209	name[0] = i2c_smbus_read_byte_data(client, 0x80);
	210	name[1] = i2c_smbus_read_byte_data(client, 0x81);
	211	name[2] = i2c_smbus_read_byte_data(client, 0x82);
	212	name[3] = i2c_smbus_read_byte_data(client, 0x83);
8b925a3d JD	213
8b925a3d JD	214	if (!memcmp(name, "PCG-", 4) \|\| !memcmp(name, "VGN-", 4)) {
f741f673	215	dev_info(&client->dev, "Vaio EEPROM detected, "
0f2cbd38	216	"enabling privacy protection\n");
1da177e4 LT	217	data->nature = VAIO;
	218	}
	219	}
	220
	221	/* create the sysfs eeprom file */
f741f673	222	err = sysfs_create_bin_file(&client->dev.kobj, &eeprom_attr);
7d9db67f JD	223	if (err)
7d9db67f JD	224	goto exit_detach;
1da177e4 LT	225
	226	return 0;
	227
7d9db67f	228	exit_detach:
f741f673	229	i2c_detach_client(client);
1da177e4 LT	230	exit_kfree:
	231	kfree(data);
	232	exit:
	233	return err;
	234	}
	235
	236	static int eeprom_detach_client(struct i2c_client *client)
	237	{
	238	int err;
	239
7d9db67f JD	240	sysfs_remove_bin_file(&client->dev.kobj, &eeprom_attr);
7d9db67f JD	241
1da177e4	242	err = i2c_detach_client(client);
7bef5594	243	if (err)
1da177e4	244	return err;
1da177e4 LT	245
	246	kfree(i2c_get_clientdata(client));
	247
	248	return 0;
	249	}
	250
	251	static int __init eeprom_init(void)
	252	{
	253	return i2c_add_driver(&eeprom_driver);
	254	}
	255
	256	static void __exit eeprom_exit(void)
	257	{
	258	i2c_del_driver(&eeprom_driver);
	259	}
	260
	261
	262	MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
	263	"Philip Edelbrock <phil@netroedge.com> and "
	264	"Greg Kroah-Hartman <greg@kroah.com>");
	265	MODULE_DESCRIPTION("I2C EEPROM driver");
	266	MODULE_LICENSE("GPL");
	267
	268	module_init(eeprom_init);
	269	module_exit(eeprom_exit);