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1da177e4 LT |
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 | ||
1da177e4 LT |
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> | |
1da177e4 LT |
36 | |
37 | /* Addresses to scan */ | |
38 | static unsigned short normal_i2c[] = { 0x50, 0x51, 0x52, 0x53, 0x54, | |
39 | 0x55, 0x56, 0x57, I2C_CLIENT_END }; | |
1da177e4 LT |
40 | |
41 | /* Insmod parameters */ | |
f4b50261 | 42 | I2C_CLIENT_INSMOD_1(eeprom); |
1da177e4 LT |
43 | |
44 | ||
45 | /* Size of EEPROM in bytes */ | |
46 | #define EEPROM_SIZE 256 | |
47 | ||
48 | /* possible types of eeprom devices */ | |
49 | enum eeprom_nature { | |
50 | UNKNOWN, | |
51 | VAIO, | |
52 | }; | |
53 | ||
54 | /* Each client has this additional data */ | |
55 | struct eeprom_data { | |
56 | struct i2c_client client; | |
57 | struct semaphore 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; | |
62 | }; | |
63 | ||
64 | ||
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); | |
68 | ||
69 | /* This is the driver that will be inserted */ | |
70 | static struct i2c_driver eeprom_driver = { | |
71 | .owner = THIS_MODULE, | |
72 | .name = "eeprom", | |
73 | .id = I2C_DRIVERID_EEPROM, | |
74 | .flags = I2C_DF_NOTIFY, | |
75 | .attach_adapter = eeprom_attach_adapter, | |
76 | .detach_client = eeprom_detach_client, | |
77 | }; | |
78 | ||
79 | static void eeprom_update_client(struct i2c_client *client, u8 slice) | |
80 | { | |
81 | struct eeprom_data *data = i2c_get_clientdata(client); | |
82 | int i, j; | |
83 | ||
84 | down(&data->update_lock); | |
85 | ||
86 | if (!(data->valid & (1 << slice)) || | |
87 | time_after(jiffies, data->last_updated[slice] + 300 * HZ)) { | |
88 | dev_dbg(&client->dev, "Starting eeprom update, slice %u\n", slice); | |
89 | ||
90 | if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) { | |
30dac746 JD |
91 | for (i = slice << 5; i < (slice + 1) << 5; i += I2C_SMBUS_BLOCK_MAX) |
92 | if (i2c_smbus_read_i2c_block_data(client, i, data->data + i) != I2C_SMBUS_BLOCK_MAX) | |
1da177e4 LT |
93 | goto exit; |
94 | } else { | |
95 | if (i2c_smbus_write_byte(client, slice << 5)) { | |
96 | dev_dbg(&client->dev, "eeprom read start has failed!\n"); | |
97 | goto exit; | |
98 | } | |
99 | for (i = slice << 5; i < (slice + 1) << 5; i++) { | |
100 | j = i2c_smbus_read_byte(client); | |
101 | if (j < 0) | |
102 | goto exit; | |
103 | data->data[i] = (u8) j; | |
104 | } | |
105 | } | |
106 | data->last_updated[slice] = jiffies; | |
107 | data->valid |= (1 << slice); | |
108 | } | |
109 | exit: | |
110 | up(&data->update_lock); | |
111 | } | |
112 | ||
113 | static ssize_t eeprom_read(struct kobject *kobj, char *buf, loff_t off, size_t count) | |
114 | { | |
115 | struct i2c_client *client = to_i2c_client(container_of(kobj, struct device, kobj)); | |
116 | struct eeprom_data *data = i2c_get_clientdata(client); | |
117 | u8 slice; | |
118 | ||
119 | if (off > EEPROM_SIZE) | |
120 | return 0; | |
121 | if (off + count > EEPROM_SIZE) | |
122 | count = EEPROM_SIZE - off; | |
123 | ||
124 | /* Only refresh slices which contain requested bytes */ | |
125 | for (slice = off >> 5; slice <= (off + count - 1) >> 5; slice++) | |
126 | eeprom_update_client(client, slice); | |
127 | ||
128 | /* Hide Vaio security settings to regular users (16 first bytes) */ | |
129 | if (data->nature == VAIO && off < 16 && !capable(CAP_SYS_ADMIN)) { | |
130 | size_t in_row1 = 16 - off; | |
131 | in_row1 = min(in_row1, count); | |
132 | memset(buf, 0, in_row1); | |
133 | if (count - in_row1 > 0) | |
134 | memcpy(buf + in_row1, &data->data[16], count - in_row1); | |
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, | |
146 | .owner = THIS_MODULE, | |
147 | }, | |
148 | .size = EEPROM_SIZE, | |
149 | .read = eeprom_read, | |
150 | }; | |
151 | ||
152 | static int eeprom_attach_adapter(struct i2c_adapter *adapter) | |
153 | { | |
2ed2dc3c | 154 | return i2c_probe(adapter, &addr_data, eeprom_detect); |
1da177e4 LT |
155 | } |
156 | ||
2ed2dc3c | 157 | /* This function is called by i2c_probe */ |
1da177e4 LT |
158 | int eeprom_detect(struct i2c_adapter *adapter, int address, int kind) |
159 | { | |
160 | struct i2c_client *new_client; | |
161 | struct eeprom_data *data; | |
162 | int err = 0; | |
163 | ||
164 | /* There are three ways we can read the EEPROM data: | |
165 | (1) I2C block reads (faster, but unsupported by most adapters) | |
166 | (2) Consecutive byte reads (100% overhead) | |
167 | (3) Regular byte data reads (200% overhead) | |
168 | The third method is not implemented by this driver because all | |
169 | known adapters support at least the second. */ | |
170 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA | |
171 | | I2C_FUNC_SMBUS_BYTE)) | |
172 | goto exit; | |
173 | ||
1da177e4 LT |
174 | if (!(data = kmalloc(sizeof(struct eeprom_data), GFP_KERNEL))) { |
175 | err = -ENOMEM; | |
176 | goto exit; | |
177 | } | |
178 | memset(data, 0, sizeof(struct eeprom_data)); | |
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 | ||
1da177e4 LT |
188 | /* Fill in the remaining client fields */ |
189 | strlcpy(new_client->name, "eeprom", I2C_NAME_SIZE); | |
190 | data->valid = 0; | |
191 | init_MUTEX(&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); | |
7bef5594 | 227 | if (err) |
1da177e4 | 228 | return err; |
1da177e4 LT |
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); |