1 /*
2 eeprom.c - Part of lm_sensors, Linux kernel modules for hardware
3 monitoring
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.
8
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
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
29 #include <linux/kernel.h>
30 #include <linux/init.h>
31 #include <linux/module.h>
32 #include <linux/slab.h>
33 #include <linux/sched.h>
34 #include <linux/jiffies.h>
35 #include <linux/i2c.h>
36 #include <linux/mutex.h>
37
38 /* Addresses to scan */
39 static unsigned short normal_i2c[] = { 0x50, 0x51, 0x52, 0x53, 0x54,
40 0x55, 0x56, 0x57, I2C_CLIENT_END };
41
42 /* Insmod parameters */
43 I2C_CLIENT_INSMOD_1(eeprom);
44
45
46 /* Size of EEPROM in bytes */
47 #define EEPROM_SIZE 256
48
49 /* possible types of eeprom devices */
50 enum eeprom_nature {
51 UNKNOWN,
52 VAIO,
53 };
54
55 /* Each client has this additional data */
56 struct eeprom_data {
57 struct i2c_client client;
58 struct mutex update_lock;
59 u8 valid; /* bitfield, bit!=0 if slice is valid */
60 unsigned long last_updated[8]; /* In jiffies, 8 slices */
61 u8 data[EEPROM_SIZE]; /* Register values */
62 enum eeprom_nature nature;
63 };
64
65
66 static int eeprom_attach_adapter(struct i2c_adapter *adapter);
67 static int eeprom_detect(struct i2c_adapter *adapter, int address, int kind);
68 static int eeprom_detach_client(struct i2c_client *client);
69
70 /* This is the driver that will be inserted */
71 static struct i2c_driver eeprom_driver = {
72 .driver = {
73 .name = "eeprom",
74 },
75 .id = I2C_DRIVERID_EEPROM,
76 .attach_adapter = eeprom_attach_adapter,
77 .detach_client = eeprom_detach_client,
78 };
79
80 static void eeprom_update_client(struct i2c_client *client, u8 slice)
81 {
82 struct eeprom_data *data = i2c_get_clientdata(client);
83 int i, j;
84
85 mutex_lock(&data->update_lock);
86
87 if (!(data->valid & (1 << slice)) ||
88 time_after(jiffies, data->last_updated[slice] + 300 * HZ)) {
89 dev_dbg(&client->dev, "Starting eeprom update, slice %u\n", slice);
90
91 if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
92 for (i = slice << 5; i < (slice + 1) << 5; i += I2C_SMBUS_BLOCK_MAX)
93 if (i2c_smbus_read_i2c_block_data(client, i, data->data + i) != I2C_SMBUS_BLOCK_MAX)
94 goto exit;
95 } else {
96 if (i2c_smbus_write_byte(client, slice << 5)) {
97 dev_dbg(&client->dev, "eeprom read start has failed!\n");
98 goto exit;
99 }
100 for (i = slice << 5; i < (slice + 1) << 5; i++) {
101 j = i2c_smbus_read_byte(client);
102 if (j < 0)
103 goto exit;
104 data->data[i] = (u8) j;
105 }
106 }
107 data->last_updated[slice] = jiffies;
108 data->valid |= (1 << slice);
109 }
110 exit:
111 mutex_unlock(&data->update_lock);
112 }
113
114 static ssize_t eeprom_read(struct kobject *kobj, char *buf, loff_t off, size_t count)
115 {
116 struct i2c_client *client = to_i2c_client(container_of(kobj, struct device, kobj));
117 struct eeprom_data *data = i2c_get_clientdata(client);
118 u8 slice;
119
120 if (off > EEPROM_SIZE)
121 return 0;
122 if (off + count > EEPROM_SIZE)
123 count = EEPROM_SIZE - off;
124
125 /* Only refresh slices which contain requested bytes */
126 for (slice = off >> 5; slice <= (off + count - 1) >> 5; slice++)
127 eeprom_update_client(client, slice);
128
129 /* Hide Vaio security settings to regular users (16 first bytes) */
130 if (data->nature == VAIO && off < 16 && !capable(CAP_SYS_ADMIN)) {
131 size_t in_row1 = 16 - off;
132 in_row1 = min(in_row1, count);
133 memset(buf, 0, in_row1);
134 if (count - in_row1 > 0)
135 memcpy(buf + in_row1, &data->data[16], count - in_row1);
136 } else {
137 memcpy(buf, &data->data[off], count);
138 }
139
140 return count;
141 }
142
143 static struct bin_attribute eeprom_attr = {
144 .attr = {
145 .name = "eeprom",
146 .mode = S_IRUGO,
147 .owner = THIS_MODULE,
148 },
149 .size = EEPROM_SIZE,
150 .read = eeprom_read,
151 };
152
153 static int eeprom_attach_adapter(struct i2c_adapter *adapter)
154 {
155 return i2c_probe(adapter, &addr_data, eeprom_detect);
156 }
157
158 /* This function is called by i2c_probe */
159 static int eeprom_detect(struct i2c_adapter *adapter, int address, int kind)
160 {
161 struct i2c_client *new_client;
162 struct eeprom_data *data;
163 int err = 0;
164
165 /* There are three ways we can read the EEPROM data:
166 (1) I2C block reads (faster, but unsupported by most adapters)
167 (2) Consecutive byte reads (100% overhead)
168 (3) Regular byte data reads (200% overhead)
169 The third method is not implemented by this driver because all
170 known adapters support at least the second. */
171 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA
172 | I2C_FUNC_SMBUS_BYTE))
173 goto exit;
174
175 if (!(data = kzalloc(sizeof(struct eeprom_data), GFP_KERNEL))) {
176 err = -ENOMEM;
177 goto exit;
178 }
179
180 new_client = &data->client;
181 memset(data->data, 0xff, EEPROM_SIZE);
182 i2c_set_clientdata(new_client, data);
183 new_client->addr = address;
184 new_client->adapter = adapter;
185 new_client->driver = &eeprom_driver;
186 new_client->flags = 0;
187
188 /* Fill in the remaining client fields */
189 strlcpy(new_client->name, "eeprom", I2C_NAME_SIZE);
190 data->valid = 0;
191 mutex_init(&data->update_lock);
192 data->nature = UNKNOWN;
193
194 /* Tell the I2C layer a new client has arrived */
195 if ((err = i2c_attach_client(new_client)))
196 goto exit_kfree;
197
198 /* Detect the Vaio nature of EEPROMs.
199 We use the "PCG-" prefix as the signature. */
200 if (address == 0x57) {
201 if (i2c_smbus_read_byte_data(new_client, 0x80) == 'P'
202 && i2c_smbus_read_byte(new_client) == 'C'
203 && i2c_smbus_read_byte(new_client) == 'G'
204 && i2c_smbus_read_byte(new_client) == '-') {
205 dev_info(&new_client->dev, "Vaio EEPROM detected, "
206 "enabling password protection\n");
207 data->nature = VAIO;
208 }
209 }
210
211 /* create the sysfs eeprom file */
212 sysfs_create_bin_file(&new_client->dev.kobj, &eeprom_attr);
213
214 return 0;
215
216 exit_kfree:
217 kfree(data);
218 exit:
219 return err;
220 }
221
222 static int eeprom_detach_client(struct i2c_client *client)
223 {
224 int err;
225
226 err = i2c_detach_client(client);
227 if (err)
228 return err;
229
230 kfree(i2c_get_clientdata(client));
231
232 return 0;
233 }
234
235 static int __init eeprom_init(void)
236 {
237 return i2c_add_driver(&eeprom_driver);
238 }
239
240 static void __exit eeprom_exit(void)
241 {
242 i2c_del_driver(&eeprom_driver);
243 }
244
245
246 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
247 "Philip Edelbrock <phil@netroedge.com> and "
248 "Greg Kroah-Hartman <greg@kroah.com>");
249 MODULE_DESCRIPTION("I2C EEPROM driver");
250 MODULE_LICENSE("GPL");
251
252 module_init(eeprom_init);
253 module_exit(eeprom_exit);
254
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