1 /* 2 * lm92 - Hardware monitoring driver 3 * Copyright (C) 2005 Jean Delvare <khali@linux-fr.org> 4 * 5 * Based on the lm90 driver, with some ideas taken from the lm_sensors 6 * lm92 driver as well. 7 * 8 * The LM92 is a sensor chip made by National Semiconductor. It reports 9 * its own temperature with a 0.0625 deg resolution and a 0.33 deg 10 * accuracy. Complete datasheet can be obtained from National's website 11 * at: 12 * http://www.national.com/pf/LM/LM92.html 13 * 14 * This driver also supports the MAX6635 sensor chip made by Maxim. 15 * This chip is compatible with the LM92, but has a lesser accuracy 16 * (1.0 deg). Complete datasheet can be obtained from Maxim's website 17 * at: 18 * http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3074 19 * 20 * Since the LM92 was the first chipset supported by this driver, most 21 * comments will refer to this chipset, but are actually general and 22 * concern all supported chipsets, unless mentioned otherwise. 23 * 24 * Support could easily be added for the National Semiconductor LM76 25 * and Maxim MAX6633 and MAX6634 chips, which are mostly compatible 26 * with the LM92. 27 * 28 * This program is free software; you can redistribute it and/or modify 29 * it under the terms of the GNU General Public License as published by 30 * the Free Software Foundation; either version 2 of the License, or 31 * (at your option) any later version. 32 * 33 * This program is distributed in the hope that it will be useful, 34 * but WITHOUT ANY WARRANTY; without even the implied warranty of 35 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 36 * GNU General Public License for more details. 37 * 38 * You should have received a copy of the GNU General Public License 39 * along with this program; if not, write to the Free Software 40 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 41 */ 42 43 #include <linux/module.h> 44 #include <linux/init.h> 45 #include <linux/slab.h> 46 #include <linux/i2c.h> 47 #include <linux/hwmon.h> 48 #include <linux/err.h> 49 #include <linux/mutex.h> 50 51 /* The LM92 and MAX6635 have 2 two-state pins for address selection, 52 resulting in 4 possible addresses. */ 53 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 54 I2C_CLIENT_END }; 55 56 /* Insmod parameters */ 57 I2C_CLIENT_INSMOD_1(lm92); 58 59 /* The LM92 registers */ 60 #define LM92_REG_CONFIG 0x01 /* 8-bit, RW */ 61 #define LM92_REG_TEMP 0x00 /* 16-bit, RO */ 62 #define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */ 63 #define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */ 64 #define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */ 65 #define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */ 66 #define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */ 67 68 /* The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius, 69 left-justified in 16-bit registers. No rounding is done, with such 70 a resolution it's just not worth it. Note that the MAX6635 doesn't 71 make use of the 4 lower bits for limits (i.e. effective resolution 72 for limits is 1 degree Celsius). */ 73 static inline int TEMP_FROM_REG(s16 reg) 74 { 75 return reg / 8 * 625 / 10; 76 } 77 78 static inline s16 TEMP_TO_REG(int val) 79 { 80 if (val <= -60000) 81 return -60000 * 10 / 625 * 8; 82 if (val >= 160000) 83 return 160000 * 10 / 625 * 8; 84 return val * 10 / 625 * 8; 85 } 86 87 /* Alarm flags are stored in the 3 LSB of the temperature register */ 88 static inline u8 ALARMS_FROM_REG(s16 reg) 89 { 90 return reg & 0x0007; 91 } 92 93 /* Driver data (common to all clients) */ 94 static struct i2c_driver lm92_driver; 95 96 /* Client data (each client gets its own) */ 97 struct lm92_data { 98 struct i2c_client client; 99 struct device *hwmon_dev; 100 struct mutex update_lock; 101 char valid; /* zero until following fields are valid */ 102 unsigned long last_updated; /* in jiffies */ 103 104 /* registers values */ 105 s16 temp1_input, temp1_crit, temp1_min, temp1_max, temp1_hyst; 106 }; 107 108 109 /* 110 * Sysfs attributes and callback functions 111 */ 112 113 static struct lm92_data *lm92_update_device(struct device *dev) 114 { 115 struct i2c_client *client = to_i2c_client(dev); 116 struct lm92_data *data = i2c_get_clientdata(client); 117 118 mutex_lock(&data->update_lock); 119 120 if (time_after(jiffies, data->last_updated + HZ) 121 || !data->valid) { 122 dev_dbg(&client->dev, "Updating lm92 data\n"); 123 data->temp1_input = swab16(i2c_smbus_read_word_data(client, 124 LM92_REG_TEMP)); 125 data->temp1_hyst = swab16(i2c_smbus_read_word_data(client, 126 LM92_REG_TEMP_HYST)); 127 data->temp1_crit = swab16(i2c_smbus_read_word_data(client, 128 LM92_REG_TEMP_CRIT)); 129 data->temp1_min = swab16(i2c_smbus_read_word_data(client, 130 LM92_REG_TEMP_LOW)); 131 data->temp1_max = swab16(i2c_smbus_read_word_data(client, 132 LM92_REG_TEMP_HIGH)); 133 134 data->last_updated = jiffies; 135 data->valid = 1; 136 } 137 138 mutex_unlock(&data->update_lock); 139 140 return data; 141 } 142 143 #define show_temp(value) \ 144 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \ 145 { \ 146 struct lm92_data *data = lm92_update_device(dev); \ 147 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->value)); \ 148 } 149 show_temp(temp1_input); 150 show_temp(temp1_crit); 151 show_temp(temp1_min); 152 show_temp(temp1_max); 153 154 #define set_temp(value, reg) \ 155 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, \ 156 size_t count) \ 157 { \ 158 struct i2c_client *client = to_i2c_client(dev); \ 159 struct lm92_data *data = i2c_get_clientdata(client); \ 160 long val = simple_strtol(buf, NULL, 10); \ 161 \ 162 mutex_lock(&data->update_lock); \ 163 data->value = TEMP_TO_REG(val); \ 164 i2c_smbus_write_word_data(client, reg, swab16(data->value)); \ 165 mutex_unlock(&data->update_lock); \ 166 return count; \ 167 } 168 set_temp(temp1_crit, LM92_REG_TEMP_CRIT); 169 set_temp(temp1_min, LM92_REG_TEMP_LOW); 170 set_temp(temp1_max, LM92_REG_TEMP_HIGH); 171 172 static ssize_t show_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf) 173 { 174 struct lm92_data *data = lm92_update_device(dev); 175 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_crit) 176 - TEMP_FROM_REG(data->temp1_hyst)); 177 } 178 static ssize_t show_temp1_max_hyst(struct device *dev, struct device_attribute *attr, char *buf) 179 { 180 struct lm92_data *data = lm92_update_device(dev); 181 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_max) 182 - TEMP_FROM_REG(data->temp1_hyst)); 183 } 184 static ssize_t show_temp1_min_hyst(struct device *dev, struct device_attribute *attr, char *buf) 185 { 186 struct lm92_data *data = lm92_update_device(dev); 187 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_min) 188 + TEMP_FROM_REG(data->temp1_hyst)); 189 } 190 191 static ssize_t set_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf, 192 size_t count) 193 { 194 struct i2c_client *client = to_i2c_client(dev); 195 struct lm92_data *data = i2c_get_clientdata(client); 196 long val = simple_strtol(buf, NULL, 10); 197 198 mutex_lock(&data->update_lock); 199 data->temp1_hyst = TEMP_FROM_REG(data->temp1_crit) - val; 200 i2c_smbus_write_word_data(client, LM92_REG_TEMP_HYST, 201 swab16(TEMP_TO_REG(data->temp1_hyst))); 202 mutex_unlock(&data->update_lock); 203 return count; 204 } 205 206 static ssize_t show_alarms(struct device *dev, struct device_attribute *attr, char *buf) 207 { 208 struct lm92_data *data = lm92_update_device(dev); 209 return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp1_input)); 210 } 211 212 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL); 213 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit, 214 set_temp1_crit); 215 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst, 216 set_temp1_crit_hyst); 217 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min, 218 set_temp1_min); 219 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL); 220 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max, 221 set_temp1_max); 222 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL); 223 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL); 224 225 226 /* 227 * Detection and registration 228 */ 229 230 static void lm92_init_client(struct i2c_client *client) 231 { 232 u8 config; 233 234 /* Start the conversions if needed */ 235 config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG); 236 if (config & 0x01) 237 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG, 238 config & 0xFE); 239 } 240 241 /* The MAX6635 has no identification register, so we have to use tricks 242 to identify it reliably. This is somewhat slow. 243 Note that we do NOT rely on the 2 MSB of the configuration register 244 always reading 0, as suggested by the datasheet, because it was once 245 reported not to be true. */ 246 static int max6635_check(struct i2c_client *client) 247 { 248 u16 temp_low, temp_high, temp_hyst, temp_crit; 249 u8 conf; 250 int i; 251 252 /* No manufacturer ID register, so a read from this address will 253 always return the last read value. */ 254 temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW); 255 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low) 256 return 0; 257 temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH); 258 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high) 259 return 0; 260 261 /* Limits are stored as integer values (signed, 9-bit). */ 262 if ((temp_low & 0x7f00) || (temp_high & 0x7f00)) 263 return 0; 264 temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST); 265 temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT); 266 if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00)) 267 return 0; 268 269 /* Registers addresses were found to cycle over 16-byte boundaries. 270 We don't test all registers with all offsets so as to save some 271 reads and time, but this should still be sufficient to dismiss 272 non-MAX6635 chips. */ 273 conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG); 274 for (i=16; i<96; i*=2) { 275 if (temp_hyst != i2c_smbus_read_word_data(client, 276 LM92_REG_TEMP_HYST + i - 16) 277 || temp_crit != i2c_smbus_read_word_data(client, 278 LM92_REG_TEMP_CRIT + i) 279 || temp_low != i2c_smbus_read_word_data(client, 280 LM92_REG_TEMP_LOW + i + 16) 281 || temp_high != i2c_smbus_read_word_data(client, 282 LM92_REG_TEMP_HIGH + i + 32) 283 || conf != i2c_smbus_read_byte_data(client, 284 LM92_REG_CONFIG + i)) 285 return 0; 286 } 287 288 return 1; 289 } 290 291 static struct attribute *lm92_attributes[] = { 292 &dev_attr_temp1_input.attr, 293 &dev_attr_temp1_crit.attr, 294 &dev_attr_temp1_crit_hyst.attr, 295 &dev_attr_temp1_min.attr, 296 &dev_attr_temp1_min_hyst.attr, 297 &dev_attr_temp1_max.attr, 298 &dev_attr_temp1_max_hyst.attr, 299 &dev_attr_alarms.attr, 300 301 NULL 302 }; 303 304 static const struct attribute_group lm92_group = { 305 .attrs = lm92_attributes, 306 }; 307 308 /* The following function does more than just detection. If detection 309 succeeds, it also registers the new chip. */ 310 static int lm92_detect(struct i2c_adapter *adapter, int address, int kind) 311 { 312 struct i2c_client *new_client; 313 struct lm92_data *data; 314 int err = 0; 315 char *name; 316 317 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA 318 | I2C_FUNC_SMBUS_WORD_DATA)) 319 goto exit; 320 321 if (!(data = kzalloc(sizeof(struct lm92_data), GFP_KERNEL))) { 322 err = -ENOMEM; 323 goto exit; 324 } 325 326 /* Fill in enough client fields so that we can read from the chip, 327 which is required for identication */ 328 new_client = &data->client; 329 i2c_set_clientdata(new_client, data); 330 new_client->addr = address; 331 new_client->adapter = adapter; 332 new_client->driver = &lm92_driver; 333 new_client->flags = 0; 334 335 /* A negative kind means that the driver was loaded with no force 336 parameter (default), so we must identify the chip. */ 337 if (kind < 0) { 338 u8 config = i2c_smbus_read_byte_data(new_client, 339 LM92_REG_CONFIG); 340 u16 man_id = i2c_smbus_read_word_data(new_client, 341 LM92_REG_MAN_ID); 342 343 if ((config & 0xe0) == 0x00 344 && man_id == 0x0180) { 345 pr_info("lm92: Found National Semiconductor LM92 chip\n"); 346 kind = lm92; 347 } else 348 if (max6635_check(new_client)) { 349 pr_info("lm92: Found Maxim MAX6635 chip\n"); 350 kind = lm92; /* No separate prefix */ 351 } 352 else 353 goto exit_free; 354 } else 355 if (kind == 0) /* Default to an LM92 if forced */ 356 kind = lm92; 357 358 /* Give it the proper name */ 359 if (kind == lm92) { 360 name = "lm92"; 361 } else { /* Supposedly cannot happen */ 362 dev_dbg(&new_client->dev, "Kind out of range?\n"); 363 goto exit_free; 364 } 365 366 /* Fill in the remaining client fields */ 367 strlcpy(new_client->name, name, I2C_NAME_SIZE); 368 data->valid = 0; 369 mutex_init(&data->update_lock); 370 371 /* Tell the i2c subsystem a new client has arrived */ 372 if ((err = i2c_attach_client(new_client))) 373 goto exit_free; 374 375 /* Initialize the chipset */ 376 lm92_init_client(new_client); 377 378 /* Register sysfs hooks */ 379 if ((err = sysfs_create_group(&new_client->dev.kobj, &lm92_group))) 380 goto exit_detach; 381 382 data->hwmon_dev = hwmon_device_register(&new_client->dev); 383 if (IS_ERR(data->hwmon_dev)) { 384 err = PTR_ERR(data->hwmon_dev); 385 goto exit_remove; 386 } 387 388 return 0; 389 390 exit_remove: 391 sysfs_remove_group(&new_client->dev.kobj, &lm92_group); 392 exit_detach: 393 i2c_detach_client(new_client); 394 exit_free: 395 kfree(data); 396 exit: 397 return err; 398 } 399 400 static int lm92_attach_adapter(struct i2c_adapter *adapter) 401 { 402 if (!(adapter->class & I2C_CLASS_HWMON)) 403 return 0; 404 return i2c_probe(adapter, &addr_data, lm92_detect); 405 } 406 407 static int lm92_detach_client(struct i2c_client *client) 408 { 409 struct lm92_data *data = i2c_get_clientdata(client); 410 int err; 411 412 hwmon_device_unregister(data->hwmon_dev); 413 sysfs_remove_group(&client->dev.kobj, &lm92_group); 414 415 if ((err = i2c_detach_client(client))) 416 return err; 417 418 kfree(data); 419 return 0; 420 } 421 422 423 /* 424 * Module and driver stuff 425 */ 426 427 static struct i2c_driver lm92_driver = { 428 .driver = { 429 .name = "lm92", 430 }, 431 .id = I2C_DRIVERID_LM92, 432 .attach_adapter = lm92_attach_adapter, 433 .detach_client = lm92_detach_client, 434 }; 435 436 static int __init sensors_lm92_init(void) 437 { 438 return i2c_add_driver(&lm92_driver); 439 } 440 441 static void __exit sensors_lm92_exit(void) 442 { 443 i2c_del_driver(&lm92_driver); 444 } 445 446 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); 447 MODULE_DESCRIPTION("LM92/MAX6635 driver"); 448 MODULE_LICENSE("GPL"); 449 450 module_init(sensors_lm92_init); 451 module_exit(sensors_lm92_exit); 452