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 /* 53 * The LM92 and MAX6635 have 2 two-state pins for address selection, 54 * resulting in 4 possible addresses. 55 */ 56 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 57 I2C_CLIENT_END }; 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 /* 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 */ 75 static inline int TEMP_FROM_REG(s16 reg) 76 { 77 return reg / 8 * 625 / 10; 78 } 79 80 static inline s16 TEMP_TO_REG(int val) 81 { 82 if (val <= -60000) 83 return -60000 * 10 / 625 * 8; 84 if (val >= 160000) 85 return 160000 * 10 / 625 * 8; 86 return val * 10 / 625 * 8; 87 } 88 89 /* Alarm flags are stored in the 3 LSB of the temperature register */ 90 static inline u8 ALARMS_FROM_REG(s16 reg) 91 { 92 return reg & 0x0007; 93 } 94 95 /* Driver data (common to all clients) */ 96 static struct i2c_driver lm92_driver; 97 98 /* Client data (each client gets its own) */ 99 struct lm92_data { 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 = i2c_smbus_read_word_swapped(client, 125 LM92_REG_TEMP); 126 data->temp1_hyst = i2c_smbus_read_word_swapped(client, 127 LM92_REG_TEMP_HYST); 128 data->temp1_crit = i2c_smbus_read_word_swapped(client, 129 LM92_REG_TEMP_CRIT); 130 data->temp1_min = i2c_smbus_read_word_swapped(client, 131 LM92_REG_TEMP_LOW); 132 data->temp1_max = i2c_smbus_read_word_swapped(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, \ 146 char *buf) \ 147 { \ 148 struct lm92_data *data = lm92_update_device(dev); \ 149 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->value)); \ 150 } 151 show_temp(temp1_input); 152 show_temp(temp1_crit); 153 show_temp(temp1_min); 154 show_temp(temp1_max); 155 156 #define set_temp(value, reg) \ 157 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, \ 158 const char *buf, \ 159 size_t count) \ 160 { \ 161 struct i2c_client *client = to_i2c_client(dev); \ 162 struct lm92_data *data = i2c_get_clientdata(client); \ 163 long val; \ 164 int err = kstrtol(buf, 10, &val); \ 165 if (err) \ 166 return err; \ 167 \ 168 mutex_lock(&data->update_lock); \ 169 data->value = TEMP_TO_REG(val); \ 170 i2c_smbus_write_word_swapped(client, reg, data->value); \ 171 mutex_unlock(&data->update_lock); \ 172 return count; \ 173 } 174 set_temp(temp1_crit, LM92_REG_TEMP_CRIT); 175 set_temp(temp1_min, LM92_REG_TEMP_LOW); 176 set_temp(temp1_max, LM92_REG_TEMP_HIGH); 177 178 static ssize_t show_temp1_crit_hyst(struct device *dev, 179 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_crit) 183 - TEMP_FROM_REG(data->temp1_hyst)); 184 } 185 static ssize_t show_temp1_max_hyst(struct device *dev, 186 struct device_attribute *attr, char *buf) 187 { 188 struct lm92_data *data = lm92_update_device(dev); 189 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_max) 190 - TEMP_FROM_REG(data->temp1_hyst)); 191 } 192 static ssize_t show_temp1_min_hyst(struct device *dev, 193 struct device_attribute *attr, char *buf) 194 { 195 struct lm92_data *data = lm92_update_device(dev); 196 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_min) 197 + TEMP_FROM_REG(data->temp1_hyst)); 198 } 199 200 static ssize_t set_temp1_crit_hyst(struct device *dev, 201 struct device_attribute *attr, 202 const char *buf, size_t count) 203 { 204 struct i2c_client *client = to_i2c_client(dev); 205 struct lm92_data *data = i2c_get_clientdata(client); 206 long val; 207 int err; 208 209 err = kstrtol(buf, 10, &val); 210 if (err) 211 return err; 212 213 mutex_lock(&data->update_lock); 214 data->temp1_hyst = TEMP_FROM_REG(data->temp1_crit) - val; 215 i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST, 216 TEMP_TO_REG(data->temp1_hyst)); 217 mutex_unlock(&data->update_lock); 218 return count; 219 } 220 221 static ssize_t show_alarms(struct device *dev, struct device_attribute *attr, 222 char *buf) 223 { 224 struct lm92_data *data = lm92_update_device(dev); 225 return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp1_input)); 226 } 227 228 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr, 229 char *buf) 230 { 231 int bitnr = to_sensor_dev_attr(attr)->index; 232 struct lm92_data *data = lm92_update_device(dev); 233 return sprintf(buf, "%d\n", (data->temp1_input >> bitnr) & 1); 234 } 235 236 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL); 237 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit, 238 set_temp1_crit); 239 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst, 240 set_temp1_crit_hyst); 241 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min, 242 set_temp1_min); 243 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL); 244 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max, 245 set_temp1_max); 246 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL); 247 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL); 248 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2); 249 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0); 250 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1); 251 252 253 /* 254 * Detection and registration 255 */ 256 257 static void lm92_init_client(struct i2c_client *client) 258 { 259 u8 config; 260 261 /* Start the conversions if needed */ 262 config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG); 263 if (config & 0x01) 264 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG, 265 config & 0xFE); 266 } 267 268 /* 269 * The MAX6635 has no identification register, so we have to use tricks 270 * to identify it reliably. This is somewhat slow. 271 * Note that we do NOT rely on the 2 MSB of the configuration register 272 * always reading 0, as suggested by the datasheet, because it was once 273 * reported not to be true. 274 */ 275 static int max6635_check(struct i2c_client *client) 276 { 277 u16 temp_low, temp_high, temp_hyst, temp_crit; 278 u8 conf; 279 int i; 280 281 /* 282 * No manufacturer ID register, so a read from this address will 283 * always return the last read value. 284 */ 285 temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW); 286 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low) 287 return 0; 288 temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH); 289 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high) 290 return 0; 291 292 /* Limits are stored as integer values (signed, 9-bit). */ 293 if ((temp_low & 0x7f00) || (temp_high & 0x7f00)) 294 return 0; 295 temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST); 296 temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT); 297 if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00)) 298 return 0; 299 300 /* 301 * Registers addresses were found to cycle over 16-byte boundaries. 302 * We don't test all registers with all offsets so as to save some 303 * reads and time, but this should still be sufficient to dismiss 304 * non-MAX6635 chips. 305 */ 306 conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG); 307 for (i = 16; i < 96; i *= 2) { 308 if (temp_hyst != i2c_smbus_read_word_data(client, 309 LM92_REG_TEMP_HYST + i - 16) 310 || temp_crit != i2c_smbus_read_word_data(client, 311 LM92_REG_TEMP_CRIT + i) 312 || temp_low != i2c_smbus_read_word_data(client, 313 LM92_REG_TEMP_LOW + i + 16) 314 || temp_high != i2c_smbus_read_word_data(client, 315 LM92_REG_TEMP_HIGH + i + 32) 316 || conf != i2c_smbus_read_byte_data(client, 317 LM92_REG_CONFIG + i)) 318 return 0; 319 } 320 321 return 1; 322 } 323 324 static struct attribute *lm92_attributes[] = { 325 &dev_attr_temp1_input.attr, 326 &dev_attr_temp1_crit.attr, 327 &dev_attr_temp1_crit_hyst.attr, 328 &dev_attr_temp1_min.attr, 329 &dev_attr_temp1_min_hyst.attr, 330 &dev_attr_temp1_max.attr, 331 &dev_attr_temp1_max_hyst.attr, 332 &dev_attr_alarms.attr, 333 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr, 334 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr, 335 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, 336 NULL 337 }; 338 339 static const struct attribute_group lm92_group = { 340 .attrs = lm92_attributes, 341 }; 342 343 /* Return 0 if detection is successful, -ENODEV otherwise */ 344 static int lm92_detect(struct i2c_client *new_client, 345 struct i2c_board_info *info) 346 { 347 struct i2c_adapter *adapter = new_client->adapter; 348 u8 config; 349 u16 man_id; 350 351 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA 352 | I2C_FUNC_SMBUS_WORD_DATA)) 353 return -ENODEV; 354 355 config = i2c_smbus_read_byte_data(new_client, LM92_REG_CONFIG); 356 man_id = i2c_smbus_read_word_data(new_client, LM92_REG_MAN_ID); 357 358 if ((config & 0xe0) == 0x00 && man_id == 0x0180) 359 pr_info("lm92: Found National Semiconductor LM92 chip\n"); 360 else if (max6635_check(new_client)) 361 pr_info("lm92: Found Maxim MAX6635 chip\n"); 362 else 363 return -ENODEV; 364 365 strlcpy(info->type, "lm92", I2C_NAME_SIZE); 366 367 return 0; 368 } 369 370 static int lm92_probe(struct i2c_client *new_client, 371 const struct i2c_device_id *id) 372 { 373 struct lm92_data *data; 374 int err; 375 376 data = kzalloc(sizeof(struct lm92_data), GFP_KERNEL); 377 if (!data) { 378 err = -ENOMEM; 379 goto exit; 380 } 381 382 i2c_set_clientdata(new_client, data); 383 data->valid = 0; 384 mutex_init(&data->update_lock); 385 386 /* Initialize the chipset */ 387 lm92_init_client(new_client); 388 389 /* Register sysfs hooks */ 390 err = sysfs_create_group(&new_client->dev.kobj, &lm92_group); 391 if (err) 392 goto exit_free; 393 394 data->hwmon_dev = hwmon_device_register(&new_client->dev); 395 if (IS_ERR(data->hwmon_dev)) { 396 err = PTR_ERR(data->hwmon_dev); 397 goto exit_remove; 398 } 399 400 return 0; 401 402 exit_remove: 403 sysfs_remove_group(&new_client->dev.kobj, &lm92_group); 404 exit_free: 405 kfree(data); 406 exit: 407 return err; 408 } 409 410 static int lm92_remove(struct i2c_client *client) 411 { 412 struct lm92_data *data = i2c_get_clientdata(client); 413 414 hwmon_device_unregister(data->hwmon_dev); 415 sysfs_remove_group(&client->dev.kobj, &lm92_group); 416 417 kfree(data); 418 return 0; 419 } 420 421 422 /* 423 * Module and driver stuff 424 */ 425 426 static const struct i2c_device_id lm92_id[] = { 427 { "lm92", 0 }, 428 /* max6635 could be added here */ 429 { } 430 }; 431 MODULE_DEVICE_TABLE(i2c, lm92_id); 432 433 static struct i2c_driver lm92_driver = { 434 .class = I2C_CLASS_HWMON, 435 .driver = { 436 .name = "lm92", 437 }, 438 .probe = lm92_probe, 439 .remove = lm92_remove, 440 .id_table = lm92_id, 441 .detect = lm92_detect, 442 .address_list = normal_i2c, 443 }; 444 445 module_i2c_driver(lm92_driver); 446 447 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); 448 MODULE_DESCRIPTION("LM92/MAX6635 driver"); 449 MODULE_LICENSE("GPL"); 450