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/config.h>
30 #include <linux/kernel.h>
31 #include <linux/init.h>
32 #include <linux/module.h>
33 #include <linux/slab.h>
34 #include <linux/sched.h>
35 #include <linux/i2c.h>
36 #include <linux/i2c-sensor.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 static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END };
42
43 /* Insmod parameters */
44 SENSORS_INSMOD_1(eeprom);
45
46
47 /* Size of EEPROM in bytes */
48 #define EEPROM_SIZE 256
49
50 /* possible types of eeprom devices */
51 enum eeprom_nature {
52 UNKNOWN,
53 VAIO,
54 };
55
56 /* Each client has this additional data */
57 struct eeprom_data {
58 struct i2c_client client;
59 struct semaphore update_lock;
60 u8 valid; /* bitfield, bit!=0 if slice is valid */
61 unsigned long last_updated[8]; /* In jiffies, 8 slices */
62 u8 data[EEPROM_SIZE]; /* Register values */
63 enum eeprom_nature nature;
64 };
65
66
67 static int eeprom_attach_adapter(struct i2c_adapter *adapter);
68 static int eeprom_detect(struct i2c_adapter *adapter, int address, int kind);
69 static int eeprom_detach_client(struct i2c_client *client);
70
71 /* This is the driver that will be inserted */
72 static struct i2c_driver eeprom_driver = {
73 .owner = THIS_MODULE,
74 .name = "eeprom",
75 .id = I2C_DRIVERID_EEPROM,
76 .flags = I2C_DF_NOTIFY,
77 .attach_adapter = eeprom_attach_adapter,
78 .detach_client = eeprom_detach_client,
79 };
80
81 static void eeprom_update_client(struct i2c_client *client, u8 slice)
82 {
83 struct eeprom_data *data = i2c_get_clientdata(client);
84 int i, j;
85
86 down(&data->update_lock);
87
88 if (!(data->valid & (1 << slice)) ||
89 (jiffies - data->last_updated[slice] > 300 * HZ) ||
90 (jiffies < data->last_updated[slice])) {
91 dev_dbg(&client->dev, "Starting eeprom update, slice %u\n", slice);
92
93 if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
94 for (i = slice << 5; i < (slice + 1) << 5; i += I2C_SMBUS_I2C_BLOCK_MAX)
95 if (i2c_smbus_read_i2c_block_data(client, i, data->data + i) != I2C_SMBUS_I2C_BLOCK_MAX)
96 goto exit;
97 } else {
98 if (i2c_smbus_write_byte(client, slice << 5)) {
99 dev_dbg(&client->dev, "eeprom read start has failed!\n");
100 goto exit;
101 }
102 for (i = slice << 5; i < (slice + 1) << 5; i++) {
103 j = i2c_smbus_read_byte(client);
104 if (j < 0)
105 goto exit;
106 data->data[i] = (u8) j;
107 }
108 }
109 data->last_updated[slice] = jiffies;
110 data->valid |= (1 << slice);
111 }
112 exit:
113 up(&data->update_lock);
114 }
115
116 static ssize_t eeprom_read(struct kobject *kobj, char *buf, loff_t off, size_t count)
117 {
118 struct i2c_client *client = to_i2c_client(container_of(kobj, struct device, kobj));
119 struct eeprom_data *data = i2c_get_clientdata(client);
120 u8 slice;
121
122 if (off > EEPROM_SIZE)
123 return 0;
124 if (off + count > EEPROM_SIZE)
125 count = EEPROM_SIZE - off;
126
127 /* Only refresh slices which contain requested bytes */
128 for (slice = off >> 5; slice <= (off + count - 1) >> 5; slice++)
129 eeprom_update_client(client, slice);
130
131 /* Hide Vaio security settings to regular users (16 first bytes) */
132 if (data->nature == VAIO && off < 16 && !capable(CAP_SYS_ADMIN)) {
133 size_t in_row1 = 16 - off;
134 in_row1 = min(in_row1, count);
135 memset(buf, 0, in_row1);
136 if (count - in_row1 > 0)
137 memcpy(buf + in_row1, &data->data[16], count - in_row1);
138 } else {
139 memcpy(buf, &data->data[off], count);
140 }
141
142 return count;
143 }
144
145 static struct bin_attribute eeprom_attr = {
146 .attr = {
147 .name = "eeprom",
148 .mode = S_IRUGO,
149 .owner = THIS_MODULE,
150 },
151 .size = EEPROM_SIZE,
152 .read = eeprom_read,
153 };
154
155 static int eeprom_attach_adapter(struct i2c_adapter *adapter)
156 {
157 return i2c_detect(adapter, &addr_data, eeprom_detect);
158 }
159
160 /* This function is called by i2c_detect */
161 int eeprom_detect(struct i2c_adapter *adapter, int address, int kind)
162 {
163 struct i2c_client *new_client;
164 struct eeprom_data *data;
165 int err = 0;
166
167 /* There are three ways we can read the EEPROM data:
168 (1) I2C block reads (faster, but unsupported by most adapters)
169 (2) Consecutive byte reads (100% overhead)
170 (3) Regular byte data reads (200% overhead)
171 The third method is not implemented by this driver because all
172 known adapters support at least the second. */
173 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA
174 | I2C_FUNC_SMBUS_BYTE))
175 goto exit;
176
177 /* OK. For now, we presume we have a valid client. We now create the
178 client structure, even though we cannot fill it completely yet.
179 But it allows us to access eeprom_{read,write}_value. */
180 if (!(data = kmalloc(sizeof(struct eeprom_data), GFP_KERNEL))) {
181 err = -ENOMEM;
182 goto exit;
183 }
184 memset(data, 0, sizeof(struct eeprom_data));
185
186 new_client = &data->client;
187 memset(data->data, 0xff, EEPROM_SIZE);
188 i2c_set_clientdata(new_client, data);
189 new_client->addr = address;
190 new_client->adapter = adapter;
191 new_client->driver = &eeprom_driver;
192 new_client->flags = 0;
193
194 /* prevent 24RF08 corruption */
195 i2c_smbus_write_quick(new_client, 0);
196
197 /* Fill in the remaining client fields */
198 strlcpy(new_client->name, "eeprom", I2C_NAME_SIZE);
199 data->valid = 0;
200 init_MUTEX(&data->update_lock);
201 data->nature = UNKNOWN;
202
203 /* Tell the I2C layer a new client has arrived */
204 if ((err = i2c_attach_client(new_client)))
205 goto exit_kfree;
206
207 /* Detect the Vaio nature of EEPROMs.
208 We use the "PCG-" prefix as the signature. */
209 if (address == 0x57) {
210 if (i2c_smbus_read_byte_data(new_client, 0x80) == 'P'
211 && i2c_smbus_read_byte(new_client) == 'C'
212 && i2c_smbus_read_byte(new_client) == 'G'
213 && i2c_smbus_read_byte(new_client) == '-')
214 dev_info(&new_client->dev, "Vaio EEPROM detected, "
215 "enabling password protection\n");
216 data->nature = VAIO;
217 }
218
219 /* create the sysfs eeprom file */
220 sysfs_create_bin_file(&new_client->dev.kobj, &eeprom_attr);
221
222 return 0;
223
224 exit_kfree:
225 kfree(data);
226 exit:
227 return err;
228 }
229
230 static int eeprom_detach_client(struct i2c_client *client)
231 {
232 int err;
233
234 err = i2c_detach_client(client);
235 if (err) {
236 dev_err(&client->dev, "Client deregistration failed, client not detached.\n");
237 return err;
238 }
239
240 kfree(i2c_get_clientdata(client));
241
242 return 0;
243 }
244
245 static int __init eeprom_init(void)
246 {
247 return i2c_add_driver(&eeprom_driver);
248 }
249
250 static void __exit eeprom_exit(void)
251 {
252 i2c_del_driver(&eeprom_driver);
253 }
254
255
256 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
257 "Philip Edelbrock <phil@netroedge.com> and "
258 "Greg Kroah-Hartman <greg@kroah.com>");
259 MODULE_DESCRIPTION("I2C EEPROM driver");
260 MODULE_LICENSE("GPL");
261
262 module_init(eeprom_init);
263 module_exit(eeprom_exit);
264
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