lm92.c revision 910e8dcf16dd7afc08dc1791155cc69e07ca4183
1/* 2 * lm92 - Hardware monitoring driver 3 * Copyright (C) 2005-2008 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. */ 54static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 55 I2C_CLIENT_END }; 56 57/* Insmod parameters */ 58I2C_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). */ 74static inline int TEMP_FROM_REG(s16 reg) 75{ 76 return reg / 8 * 625 / 10; 77} 78 79static 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 */ 89static inline u8 ALARMS_FROM_REG(s16 reg) 90{ 91 return reg & 0x0007; 92} 93 94/* Driver data (common to all clients) */ 95static struct i2c_driver lm92_driver; 96 97/* Client data (each client gets its own) */ 98struct lm92_data { 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 113static 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) \ 144static 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} 149show_temp(temp1_input); 150show_temp(temp1_crit); 151show_temp(temp1_min); 152show_temp(temp1_max); 153 154#define set_temp(value, reg) \ 155static 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} 168set_temp(temp1_crit, LM92_REG_TEMP_CRIT); 169set_temp(temp1_min, LM92_REG_TEMP_LOW); 170set_temp(temp1_max, LM92_REG_TEMP_HIGH); 171 172static 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} 178static 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} 184static 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 191static 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 206static 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 212static ssize_t show_alarm(struct device *dev, struct device_attribute *attr, 213 char *buf) 214{ 215 int bitnr = to_sensor_dev_attr(attr)->index; 216 struct lm92_data *data = lm92_update_device(dev); 217 return sprintf(buf, "%d\n", (data->temp1_input >> bitnr) & 1); 218} 219 220static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL); 221static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit, 222 set_temp1_crit); 223static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst, 224 set_temp1_crit_hyst); 225static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min, 226 set_temp1_min); 227static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL); 228static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max, 229 set_temp1_max); 230static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL); 231static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL); 232static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2); 233static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0); 234static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1); 235 236 237/* 238 * Detection and registration 239 */ 240 241static void lm92_init_client(struct i2c_client *client) 242{ 243 u8 config; 244 245 /* Start the conversions if needed */ 246 config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG); 247 if (config & 0x01) 248 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG, 249 config & 0xFE); 250} 251 252/* The MAX6635 has no identification register, so we have to use tricks 253 to identify it reliably. This is somewhat slow. 254 Note that we do NOT rely on the 2 MSB of the configuration register 255 always reading 0, as suggested by the datasheet, because it was once 256 reported not to be true. */ 257static int max6635_check(struct i2c_client *client) 258{ 259 u16 temp_low, temp_high, temp_hyst, temp_crit; 260 u8 conf; 261 int i; 262 263 /* No manufacturer ID register, so a read from this address will 264 always return the last read value. */ 265 temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW); 266 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low) 267 return 0; 268 temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH); 269 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high) 270 return 0; 271 272 /* Limits are stored as integer values (signed, 9-bit). */ 273 if ((temp_low & 0x7f00) || (temp_high & 0x7f00)) 274 return 0; 275 temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST); 276 temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT); 277 if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00)) 278 return 0; 279 280 /* Registers addresses were found to cycle over 16-byte boundaries. 281 We don't test all registers with all offsets so as to save some 282 reads and time, but this should still be sufficient to dismiss 283 non-MAX6635 chips. */ 284 conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG); 285 for (i=16; i<96; i*=2) { 286 if (temp_hyst != i2c_smbus_read_word_data(client, 287 LM92_REG_TEMP_HYST + i - 16) 288 || temp_crit != i2c_smbus_read_word_data(client, 289 LM92_REG_TEMP_CRIT + i) 290 || temp_low != i2c_smbus_read_word_data(client, 291 LM92_REG_TEMP_LOW + i + 16) 292 || temp_high != i2c_smbus_read_word_data(client, 293 LM92_REG_TEMP_HIGH + i + 32) 294 || conf != i2c_smbus_read_byte_data(client, 295 LM92_REG_CONFIG + i)) 296 return 0; 297 } 298 299 return 1; 300} 301 302static struct attribute *lm92_attributes[] = { 303 &dev_attr_temp1_input.attr, 304 &dev_attr_temp1_crit.attr, 305 &dev_attr_temp1_crit_hyst.attr, 306 &dev_attr_temp1_min.attr, 307 &dev_attr_temp1_min_hyst.attr, 308 &dev_attr_temp1_max.attr, 309 &dev_attr_temp1_max_hyst.attr, 310 &dev_attr_alarms.attr, 311 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr, 312 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr, 313 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, 314 NULL 315}; 316 317static const struct attribute_group lm92_group = { 318 .attrs = lm92_attributes, 319}; 320 321/* Return 0 if detection is successful, -ENODEV otherwise */ 322static int lm92_detect(struct i2c_client *new_client, int kind, 323 struct i2c_board_info *info) 324{ 325 struct i2c_adapter *adapter = new_client->adapter; 326 327 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA 328 | I2C_FUNC_SMBUS_WORD_DATA)) 329 return -ENODEV; 330 331 /* A negative kind means that the driver was loaded with no force 332 parameter (default), so we must identify the chip. */ 333 if (kind < 0) { 334 u8 config = i2c_smbus_read_byte_data(new_client, 335 LM92_REG_CONFIG); 336 u16 man_id = i2c_smbus_read_word_data(new_client, 337 LM92_REG_MAN_ID); 338 339 if ((config & 0xe0) == 0x00 340 && man_id == 0x0180) { 341 pr_info("lm92: Found National Semiconductor LM92 chip\n"); 342 kind = lm92; 343 } else 344 if (max6635_check(new_client)) { 345 pr_info("lm92: Found Maxim MAX6635 chip\n"); 346 kind = lm92; /* No separate prefix */ 347 } 348 else 349 return -ENODEV; 350 } 351 352 strlcpy(info->type, "lm92", I2C_NAME_SIZE); 353 354 return 0; 355} 356 357static int lm92_probe(struct i2c_client *new_client, 358 const struct i2c_device_id *id) 359{ 360 struct lm92_data *data; 361 int err; 362 363 data = kzalloc(sizeof(struct lm92_data), GFP_KERNEL); 364 if (!data) { 365 err = -ENOMEM; 366 goto exit; 367 } 368 369 i2c_set_clientdata(new_client, data); 370 data->valid = 0; 371 mutex_init(&data->update_lock); 372 373 /* Initialize the chipset */ 374 lm92_init_client(new_client); 375 376 /* Register sysfs hooks */ 377 if ((err = sysfs_create_group(&new_client->dev.kobj, &lm92_group))) 378 goto exit_free; 379 380 data->hwmon_dev = hwmon_device_register(&new_client->dev); 381 if (IS_ERR(data->hwmon_dev)) { 382 err = PTR_ERR(data->hwmon_dev); 383 goto exit_remove; 384 } 385 386 return 0; 387 388exit_remove: 389 sysfs_remove_group(&new_client->dev.kobj, &lm92_group); 390exit_free: 391 kfree(data); 392exit: 393 return err; 394} 395 396static int lm92_remove(struct i2c_client *client) 397{ 398 struct lm92_data *data = i2c_get_clientdata(client); 399 400 hwmon_device_unregister(data->hwmon_dev); 401 sysfs_remove_group(&client->dev.kobj, &lm92_group); 402 403 kfree(data); 404 return 0; 405} 406 407 408/* 409 * Module and driver stuff 410 */ 411 412static const struct i2c_device_id lm92_id[] = { 413 { "lm92", lm92 }, 414 /* max6635 could be added here */ 415 { } 416}; 417MODULE_DEVICE_TABLE(i2c, lm92_id); 418 419static struct i2c_driver lm92_driver = { 420 .class = I2C_CLASS_HWMON, 421 .driver = { 422 .name = "lm92", 423 }, 424 .probe = lm92_probe, 425 .remove = lm92_remove, 426 .id_table = lm92_id, 427 .detect = lm92_detect, 428 .address_data = &addr_data, 429}; 430 431static int __init sensors_lm92_init(void) 432{ 433 return i2c_add_driver(&lm92_driver); 434} 435 436static void __exit sensors_lm92_exit(void) 437{ 438 i2c_del_driver(&lm92_driver); 439} 440 441MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); 442MODULE_DESCRIPTION("LM92/MAX6635 driver"); 443MODULE_LICENSE("GPL"); 444 445module_init(sensors_lm92_init); 446module_exit(sensors_lm92_exit); 447