2 eeprom.c - Part of lm_sensors, Linux kernel modules for hardware
4 Copyright (C) 1998, 1999 Frodo Looijaard <frodol@dds.nl> and
5 Philip Edelbrock <phil@netroedge.com>
6 Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
7 Copyright (C) 2003 IBM Corp.
9 2004-01-16 Jean Delvare <khali@linux-fr.org>
10 Divide the eeprom in 32-byte (arbitrary) slices. This significantly
11 speeds sensors up, as well as various scripts using the eeprom
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.
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.
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.
29 #include <linux/kernel.h>
30 #include <linux/init.h>
31 #include <linux/module.h>
32 #include <linux/slab.h>
33 #include <linux/jiffies.h>
34 #include <linux/i2c.h>
35 #include <linux/mutex.h>
37 /* Addresses to scan */
38 static const unsigned short normal_i2c[] = { 0x50, 0x51, 0x52, 0x53, 0x54,
39 0x55, 0x56, 0x57, I2C_CLIENT_END };
41 /* Insmod parameters */
42 I2C_CLIENT_INSMOD_1(eeprom);
45 /* Size of EEPROM in bytes */
46 #define EEPROM_SIZE 256
48 /* possible types of eeprom devices */
54 /* Each client has this additional data */
56 struct i2c_client client;
57 struct mutex update_lock;
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;
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);
69 /* This is the driver that will be inserted */
70 static struct i2c_driver eeprom_driver = {
74 .attach_adapter = eeprom_attach_adapter,
75 .detach_client = eeprom_detach_client,
78 static void eeprom_update_client(struct i2c_client *client, u8 slice)
80 struct eeprom_data *data = i2c_get_clientdata(client);
83 mutex_lock(&data->update_lock);
85 if (!(data->valid & (1 << slice)) ||
86 time_after(jiffies, data->last_updated[slice] + 300 * HZ)) {
87 dev_dbg(&client->dev, "Starting eeprom update, slice %u\n", slice);
89 if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
90 for (i = slice << 5; i < (slice + 1) << 5; i += 32)
91 if (i2c_smbus_read_i2c_block_data(client, i,
96 for (i = slice << 5; i < (slice + 1) << 5; i += 2) {
97 int word = i2c_smbus_read_word_data(client, i);
100 data->data[i] = word & 0xff;
101 data->data[i + 1] = word >> 8;
104 data->last_updated[slice] = jiffies;
105 data->valid |= (1 << slice);
108 mutex_unlock(&data->update_lock);
111 static ssize_t eeprom_read(struct kobject *kobj, struct bin_attribute *bin_attr,
112 char *buf, loff_t off, size_t count)
114 struct i2c_client *client = to_i2c_client(container_of(kobj, struct device, kobj));
115 struct eeprom_data *data = i2c_get_clientdata(client);
118 if (off > EEPROM_SIZE)
120 if (off + count > EEPROM_SIZE)
121 count = EEPROM_SIZE - off;
123 /* Only refresh slices which contain requested bytes */
124 for (slice = off >> 5; slice <= (off + count - 1) >> 5; slice++)
125 eeprom_update_client(client, slice);
127 /* Hide Vaio private settings to regular users:
128 - BIOS passwords: bytes 0x00 to 0x0f
129 - UUID: bytes 0x10 to 0x1f
130 - Serial number: 0xc0 to 0xdf */
131 if (data->nature == VAIO && !capable(CAP_SYS_ADMIN)) {
134 for (i = 0; i < count; i++) {
135 if ((off + i <= 0x1f) ||
136 (off + i >= 0xc0 && off + i <= 0xdf))
139 buf[i] = data->data[off + i];
142 memcpy(buf, &data->data[off], count);
148 static struct bin_attribute eeprom_attr = {
157 static int eeprom_attach_adapter(struct i2c_adapter *adapter)
159 if (!(adapter->class & (I2C_CLASS_DDC | I2C_CLASS_SPD)))
161 return i2c_probe(adapter, &addr_data, eeprom_detect);
164 /* This function is called by i2c_probe */
165 static int eeprom_detect(struct i2c_adapter *adapter, int address, int kind)
167 struct i2c_client *new_client;
168 struct eeprom_data *data;
171 /* EDID EEPROMs are often 24C00 EEPROMs, which answer to all
172 addresses 0x50-0x57, but we only care about 0x50. So decline
173 attaching to addresses >= 0x51 on DDC buses */
174 if (!(adapter->class & I2C_CLASS_SPD) && address >= 0x51)
177 /* There are four ways we can read the EEPROM data:
178 (1) I2C block reads (faster, but unsupported by most adapters)
179 (2) Word reads (128% overhead)
180 (3) Consecutive byte reads (88% overhead, unsafe)
181 (4) Regular byte data reads (265% overhead)
182 The third and fourth methods are not implemented by this driver
183 because all known adapters support one of the first two. */
184 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)
185 && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
188 if (!(data = kzalloc(sizeof(struct eeprom_data), GFP_KERNEL))) {
193 new_client = &data->client;
194 memset(data->data, 0xff, EEPROM_SIZE);
195 i2c_set_clientdata(new_client, data);
196 new_client->addr = address;
197 new_client->adapter = adapter;
198 new_client->driver = &eeprom_driver;
199 new_client->flags = 0;
201 /* Fill in the remaining client fields */
202 strlcpy(new_client->name, "eeprom", I2C_NAME_SIZE);
204 mutex_init(&data->update_lock);
205 data->nature = UNKNOWN;
207 /* Tell the I2C layer a new client has arrived */
208 if ((err = i2c_attach_client(new_client)))
211 /* Detect the Vaio nature of EEPROMs.
212 We use the "PCG-" or "VGN-" prefix as the signature. */
214 && i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
217 name[0] = i2c_smbus_read_byte_data(new_client, 0x80);
218 name[1] = i2c_smbus_read_byte_data(new_client, 0x81);
219 name[2] = i2c_smbus_read_byte_data(new_client, 0x82);
220 name[3] = i2c_smbus_read_byte_data(new_client, 0x83);
222 if (!memcmp(name, "PCG-", 4) || !memcmp(name, "VGN-", 4)) {
223 dev_info(&new_client->dev, "Vaio EEPROM detected, "
224 "enabling privacy protection\n");
229 /* create the sysfs eeprom file */
230 err = sysfs_create_bin_file(&new_client->dev.kobj, &eeprom_attr);
237 i2c_detach_client(new_client);
244 static int eeprom_detach_client(struct i2c_client *client)
248 sysfs_remove_bin_file(&client->dev.kobj, &eeprom_attr);
250 err = i2c_detach_client(client);
254 kfree(i2c_get_clientdata(client));
259 static int __init eeprom_init(void)
261 return i2c_add_driver(&eeprom_driver);
264 static void __exit eeprom_exit(void)
266 i2c_del_driver(&eeprom_driver);
270 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
271 "Philip Edelbrock <phil@netroedge.com> and "
272 "Greg Kroah-Hartman <greg@kroah.com>");
273 MODULE_DESCRIPTION("I2C EEPROM driver");
274 MODULE_LICENSE("GPL");
276 module_init(eeprom_init);
277 module_exit(eeprom_exit);