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/hwmon-sysfs.h> 49 #include <linux/err.h> 50 #include <linux/mutex.h> 51 52 /* The LM92 and MAX6635 have 2 two-state pins for address selection, 53 resulting in 4 possible addresses. */ 54 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 55 I2C_CLIENT_END }; 56 57 /* Insmod parameters */ 58 I2C_CLIENT_INSMOD_1(lm92); 59 60 /* The LM92 registers */ 61 #define LM92_REG_CONFIG 0x01 /* 8-bit, RW */ 62 #define LM92_REG_TEMP 0x00 /* 16-bit, RO */ 63 #define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */ 64 #define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */ 65 #define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */ 66 #define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */ 67 #define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */ 68 69 /* The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius, 70 left-justified in 16-bit registers. No rounding is done, with such 71 a resolution it's just not worth it. Note that the MAX6635 doesn't 72 make use of the 4 lower bits for limits (i.e. effective resolution 73 for limits is 1 degree Celsius). */ 74 static inline int TEMP_FROM_REG(s16 reg) 75 { 76 return reg / 8 * 625 / 10; 77 } 78 79 static inline s16 TEMP_TO_REG(int val) 80 { 81 if (val <= -60000) 82 return -60000 * 10 / 625 * 8; 83 if (val >= 160000) 84 return 160000 * 10 / 625 * 8; 85 return val * 10 / 625 * 8; 86 } 87 88 /* Alarm flags are stored in the 3 LSB of the temperature register */ 89 static inline u8 ALARMS_FROM_REG(s16 reg) 90 { 91 return reg & 0x0007; 92 } 93 94 /* Driver data (common to all clients) */ 95 static struct i2c_driver lm92_driver; 96 97 /* Client data (each client gets its own) */ 98 struct lm92_data { 99 struct i2c_client client; 100 struct device *hwmon_dev; 101 struct mutex update_lock; 102 char valid; /* zero until following fields are valid */ 103 unsigned long last_updated; /* in jiffies */ 104 105 /* registers values */ 106 s16 temp1_input, temp1_crit, temp1_min, temp1_max, temp1_hyst; 107 }; 108 109 110 /* 111 * Sysfs attributes and callback functions 112 */ 113 114 static struct lm92_data *lm92_update_device(struct device *dev) 115 { 116 struct i2c_client *client = to_i2c_client(dev); 117 struct lm92_data *data = i2c_get_clientdata(client); 118 119 mutex_lock(&data->update_lock); 120 121 if (time_after(jiffies, data->last_updated + HZ) 122 || !data->valid) { 123 dev_dbg(&client->dev, "Updating lm92 data\n"); 124 data->temp1_input = swab16(i2c_smbus_read_word_data(client, 125 LM92_REG_TEMP)); 126 data->temp1_hyst = swab16(i2c_smbus_read_word_data(client, 127 LM92_REG_TEMP_HYST)); 128 data->temp1_crit = swab16(i2c_smbus_read_word_data(client, 129 LM92_REG_TEMP_CRIT)); 130 data->temp1_min = swab16(i2c_smbus_read_word_data(client, 131 LM92_REG_TEMP_LOW)); 132 data->temp1_max = swab16(i2c_smbus_read_word_data(client, 133 LM92_REG_TEMP_HIGH)); 134 135 data->last_updated = jiffies; 136 data->valid = 1; 137 } 138 139 mutex_unlock(&data->update_lock); 140 141 return data; 142 } 143 144 #define show_temp(value) \ 145 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \ 146 { \ 147 struct lm92_data *data = lm92_update_device(dev); \ 148 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->value)); \ 149 } 150 show_temp(temp1_input); 151 show_temp(temp1_crit); 152 show_temp(temp1_min); 153 show_temp(temp1_max); 154 155 #define set_temp(value, reg) \ 156 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, \ 157 size_t count) \ 158 { \ 159 struct i2c_client *client = to_i2c_client(dev); \ 160 struct lm92_data *data = i2c_get_clientdata(client); \ 161 long val = simple_strtol(buf, NULL, 10); \ 162 \ 163 mutex_lock(&data->update_lock); \ 164 data->value = TEMP_TO_REG(val); \ 165 i2c_smbus_write_word_data(client, reg, swab16(data->value)); \ 166 mutex_unlock(&data->update_lock); \ 167 return count; \ 168 } 169 set_temp(temp1_crit, LM92_REG_TEMP_CRIT); 170 set_temp(temp1_min, LM92_REG_TEMP_LOW); 171 set_temp(temp1_max, LM92_REG_TEMP_HIGH); 172 173 static ssize_t show_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf) 174 { 175 struct lm92_data *data = lm92_update_device(dev); 176 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_crit) 177 - TEMP_FROM_REG(data->temp1_hyst)); 178 } 179 static ssize_t show_temp1_max_hyst(struct device *dev, struct device_attribute *attr, char *buf) 180 { 181 struct lm92_data *data = lm92_update_device(dev); 182 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_max) 183 - TEMP_FROM_REG(data->temp1_hyst)); 184 } 185 static ssize_t show_temp1_min_hyst(struct device *dev, struct device_attribute *attr, char *buf) 186 { 187 struct lm92_data *data = lm92_update_device(dev); 188 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_min) 189 + TEMP_FROM_REG(data->temp1_hyst)); 190 } 191 192 static ssize_t set_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf, 193 size_t count) 194 { 195 struct i2c_client *client = to_i2c_client(dev); 196 struct lm92_data *data = i2c_get_clientdata(client); 197 long val = simple_strtol(buf, NULL, 10); 198 199 mutex_lock(&data->update_lock); 200 data->temp1_hyst = TEMP_FROM_REG(data->temp1_crit) - val; 201 i2c_smbus_write_word_data(client, LM92_REG_TEMP_HYST, 202 swab16(TEMP_TO_REG(data->temp1_hyst))); 203 mutex_unlock(&data->update_lock); 204 return count; 205 } 206 207 static ssize_t show_alarms(struct device *dev, struct device_attribute *attr, char *buf) 208 { 209 struct lm92_data *data = lm92_update_device(dev); 210 return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp1_input)); 211 } 212 213 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr, 214 char *buf) 215 { 216 int bitnr = to_sensor_dev_attr(attr)->index; 217 struct lm92_data *data = lm92_update_device(dev); 218 return sprintf(buf, "%d\n", (data->temp1_input >> bitnr) & 1); 219 } 220 221 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL); 222 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit, 223 set_temp1_crit); 224 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst, 225 set_temp1_crit_hyst); 226 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min, 227 set_temp1_min); 228 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL); 229 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max, 230 set_temp1_max); 231 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL); 232 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL); 233 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2); 234 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0); 235 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1); 236 237 238 /* 239 * Detection and registration 240 */ 241 242 static void lm92_init_client(struct i2c_client *client) 243 { 244 u8 config; 245 246 /* Start the conversions if needed */ 247 config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG); 248 if (config & 0x01) 249 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG, 250 config & 0xFE); 251 } 252 253 /* The MAX6635 has no identification register, so we have to use tricks 254 to identify it reliably. This is somewhat slow. 255 Note that we do NOT rely on the 2 MSB of the configuration register 256 always reading 0, as suggested by the datasheet, because it was once 257 reported not to be true. */ 258 static int max6635_check(struct i2c_client *client) 259 { 260 u16 temp_low, temp_high, temp_hyst, temp_crit; 261 u8 conf; 262 int i; 263 264 /* No manufacturer ID register, so a read from this address will 265 always return the last read value. */ 266 temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW); 267 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low) 268 return 0; 269 temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH); 270 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high) 271 return 0; 272 273 /* Limits are stored as integer values (signed, 9-bit). */ 274 if ((temp_low & 0x7f00) || (temp_high & 0x7f00)) 275 return 0; 276 temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST); 277 temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT); 278 if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00)) 279 return 0; 280 281 /* Registers addresses were found to cycle over 16-byte boundaries. 282 We don't test all registers with all offsets so as to save some 283 reads and time, but this should still be sufficient to dismiss 284 non-MAX6635 chips. */ 285 conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG); 286 for (i=16; i<96; i*=2) { 287 if (temp_hyst != i2c_smbus_read_word_data(client, 288 LM92_REG_TEMP_HYST + i - 16) 289 || temp_crit != i2c_smbus_read_word_data(client, 290 LM92_REG_TEMP_CRIT + i) 291 || temp_low != i2c_smbus_read_word_data(client, 292 LM92_REG_TEMP_LOW + i + 16) 293 || temp_high != i2c_smbus_read_word_data(client, 294 LM92_REG_TEMP_HIGH + i + 32) 295 || conf != i2c_smbus_read_byte_data(client, 296 LM92_REG_CONFIG + i)) 297 return 0; 298 } 299 300 return 1; 301 } 302 303 static struct attribute *lm92_attributes[] = { 304 &dev_attr_temp1_input.attr, 305 &dev_attr_temp1_crit.attr, 306 &dev_attr_temp1_crit_hyst.attr, 307 &dev_attr_temp1_min.attr, 308 &dev_attr_temp1_min_hyst.attr, 309 &dev_attr_temp1_max.attr, 310 &dev_attr_temp1_max_hyst.attr, 311 &dev_attr_alarms.attr, 312 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr, 313 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr, 314 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, 315 NULL 316 }; 317 318 static const struct attribute_group lm92_group = { 319 .attrs = lm92_attributes, 320 }; 321 322 /* The following function does more than just detection. If detection 323 succeeds, it also registers the new chip. */ 324 static int lm92_detect(struct i2c_adapter *adapter, int address, int kind) 325 { 326 struct i2c_client *new_client; 327 struct lm92_data *data; 328 int err = 0; 329 char *name; 330 331 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA 332 | I2C_FUNC_SMBUS_WORD_DATA)) 333 goto exit; 334 335 if (!(data = kzalloc(sizeof(struct lm92_data), GFP_KERNEL))) { 336 err = -ENOMEM; 337 goto exit; 338 } 339 340 /* Fill in enough client fields so that we can read from the chip, 341 which is required for identication */ 342 new_client = &data->client; 343 i2c_set_clientdata(new_client, data); 344 new_client->addr = address; 345 new_client->adapter = adapter; 346 new_client->driver = &lm92_driver; 347 new_client->flags = 0; 348 349 /* A negative kind means that the driver was loaded with no force 350 parameter (default), so we must identify the chip. */ 351 if (kind < 0) { 352 u8 config = i2c_smbus_read_byte_data(new_client, 353 LM92_REG_CONFIG); 354 u16 man_id = i2c_smbus_read_word_data(new_client, 355 LM92_REG_MAN_ID); 356 357 if ((config & 0xe0) == 0x00 358 && man_id == 0x0180) { 359 pr_info("lm92: Found National Semiconductor LM92 chip\n"); 360 kind = lm92; 361 } else 362 if (max6635_check(new_client)) { 363 pr_info("lm92: Found Maxim MAX6635 chip\n"); 364 kind = lm92; /* No separate prefix */ 365 } 366 else 367 goto exit_free; 368 } else 369 if (kind == 0) /* Default to an LM92 if forced */ 370 kind = lm92; 371 372 /* Give it the proper name */ 373 if (kind == lm92) { 374 name = "lm92"; 375 } else { /* Supposedly cannot happen */ 376 dev_dbg(&new_client->dev, "Kind out of range?\n"); 377 goto exit_free; 378 } 379 380 /* Fill in the remaining client fields */ 381 strlcpy(new_client->name, name, I2C_NAME_SIZE); 382 data->valid = 0; 383 mutex_init(&data->update_lock); 384 385 /* Tell the i2c subsystem a new client has arrived */ 386 if ((err = i2c_attach_client(new_client))) 387 goto exit_free; 388 389 /* Initialize the chipset */ 390 lm92_init_client(new_client); 391 392 /* Register sysfs hooks */ 393 if ((err = sysfs_create_group(&new_client->dev.kobj, &lm92_group))) 394 goto exit_detach; 395 396 data->hwmon_dev = hwmon_device_register(&new_client->dev); 397 if (IS_ERR(data->hwmon_dev)) { 398 err = PTR_ERR(data->hwmon_dev); 399 goto exit_remove; 400 } 401 402 return 0; 403 404 exit_remove: 405 sysfs_remove_group(&new_client->dev.kobj, &lm92_group); 406 exit_detach: 407 i2c_detach_client(new_client); 408 exit_free: 409 kfree(data); 410 exit: 411 return err; 412 } 413 414 static int lm92_attach_adapter(struct i2c_adapter *adapter) 415 { 416 if (!(adapter->class & I2C_CLASS_HWMON)) 417 return 0; 418 return i2c_probe(adapter, &addr_data, lm92_detect); 419 } 420 421 static int lm92_detach_client(struct i2c_client *client) 422 { 423 struct lm92_data *data = i2c_get_clientdata(client); 424 int err; 425 426 hwmon_device_unregister(data->hwmon_dev); 427 sysfs_remove_group(&client->dev.kobj, &lm92_group); 428 429 if ((err = i2c_detach_client(client))) 430 return err; 431 432 kfree(data); 433 return 0; 434 } 435 436 437 /* 438 * Module and driver stuff 439 */ 440 441 static struct i2c_driver lm92_driver = { 442 .driver = { 443 .name = "lm92", 444 }, 445 .attach_adapter = lm92_attach_adapter, 446 .detach_client = lm92_detach_client, 447 }; 448 449 static int __init sensors_lm92_init(void) 450 { 451 return i2c_add_driver(&lm92_driver); 452 } 453 454 static void __exit sensors_lm92_exit(void) 455 { 456 i2c_del_driver(&lm92_driver); 457 } 458 459 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); 460 MODULE_DESCRIPTION("LM92/MAX6635 driver"); 461 MODULE_LICENSE("GPL"); 462 463 module_init(sensors_lm92_init); 464 module_exit(sensors_lm92_exit); 465