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. */ 54 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 55 I2C_CLIENT_END }; 56 57 /* The LM92 registers */ 58 #define LM92_REG_CONFIG 0x01 /* 8-bit, RW */ 59 #define LM92_REG_TEMP 0x00 /* 16-bit, RO */ 60 #define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */ 61 #define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */ 62 #define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */ 63 #define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */ 64 #define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */ 65 66 /* The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius, 67 left-justified in 16-bit registers. No rounding is done, with such 68 a resolution it's just not worth it. Note that the MAX6635 doesn't 69 make use of the 4 lower bits for limits (i.e. effective resolution 70 for limits is 1 degree Celsius). */ 71 static inline int TEMP_FROM_REG(s16 reg) 72 { 73 return reg / 8 * 625 / 10; 74 } 75 76 static inline s16 TEMP_TO_REG(int val) 77 { 78 if (val <= -60000) 79 return -60000 * 10 / 625 * 8; 80 if (val >= 160000) 81 return 160000 * 10 / 625 * 8; 82 return val * 10 / 625 * 8; 83 } 84 85 /* Alarm flags are stored in the 3 LSB of the temperature register */ 86 static inline u8 ALARMS_FROM_REG(s16 reg) 87 { 88 return reg & 0x0007; 89 } 90 91 /* Driver data (common to all clients) */ 92 static struct i2c_driver lm92_driver; 93 94 /* Client data (each client gets its own) */ 95 struct lm92_data { 96 struct device *hwmon_dev; 97 struct mutex update_lock; 98 char valid; /* zero until following fields are valid */ 99 unsigned long last_updated; /* in jiffies */ 100 101 /* registers values */ 102 s16 temp1_input, temp1_crit, temp1_min, temp1_max, temp1_hyst; 103 }; 104 105 106 /* 107 * Sysfs attributes and callback functions 108 */ 109 110 static struct lm92_data *lm92_update_device(struct device *dev) 111 { 112 struct i2c_client *client = to_i2c_client(dev); 113 struct lm92_data *data = i2c_get_clientdata(client); 114 115 mutex_lock(&data->update_lock); 116 117 if (time_after(jiffies, data->last_updated + HZ) 118 || !data->valid) { 119 dev_dbg(&client->dev, "Updating lm92 data\n"); 120 data->temp1_input = swab16(i2c_smbus_read_word_data(client, 121 LM92_REG_TEMP)); 122 data->temp1_hyst = swab16(i2c_smbus_read_word_data(client, 123 LM92_REG_TEMP_HYST)); 124 data->temp1_crit = swab16(i2c_smbus_read_word_data(client, 125 LM92_REG_TEMP_CRIT)); 126 data->temp1_min = swab16(i2c_smbus_read_word_data(client, 127 LM92_REG_TEMP_LOW)); 128 data->temp1_max = swab16(i2c_smbus_read_word_data(client, 129 LM92_REG_TEMP_HIGH)); 130 131 data->last_updated = jiffies; 132 data->valid = 1; 133 } 134 135 mutex_unlock(&data->update_lock); 136 137 return data; 138 } 139 140 #define show_temp(value) \ 141 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \ 142 { \ 143 struct lm92_data *data = lm92_update_device(dev); \ 144 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->value)); \ 145 } 146 show_temp(temp1_input); 147 show_temp(temp1_crit); 148 show_temp(temp1_min); 149 show_temp(temp1_max); 150 151 #define set_temp(value, reg) \ 152 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, \ 153 size_t count) \ 154 { \ 155 struct i2c_client *client = to_i2c_client(dev); \ 156 struct lm92_data *data = i2c_get_clientdata(client); \ 157 long val = simple_strtol(buf, NULL, 10); \ 158 \ 159 mutex_lock(&data->update_lock); \ 160 data->value = TEMP_TO_REG(val); \ 161 i2c_smbus_write_word_data(client, reg, swab16(data->value)); \ 162 mutex_unlock(&data->update_lock); \ 163 return count; \ 164 } 165 set_temp(temp1_crit, LM92_REG_TEMP_CRIT); 166 set_temp(temp1_min, LM92_REG_TEMP_LOW); 167 set_temp(temp1_max, LM92_REG_TEMP_HIGH); 168 169 static ssize_t show_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf) 170 { 171 struct lm92_data *data = lm92_update_device(dev); 172 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_crit) 173 - TEMP_FROM_REG(data->temp1_hyst)); 174 } 175 static ssize_t show_temp1_max_hyst(struct device *dev, struct device_attribute *attr, char *buf) 176 { 177 struct lm92_data *data = lm92_update_device(dev); 178 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_max) 179 - TEMP_FROM_REG(data->temp1_hyst)); 180 } 181 static ssize_t show_temp1_min_hyst(struct device *dev, struct device_attribute *attr, char *buf) 182 { 183 struct lm92_data *data = lm92_update_device(dev); 184 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_min) 185 + TEMP_FROM_REG(data->temp1_hyst)); 186 } 187 188 static ssize_t set_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf, 189 size_t count) 190 { 191 struct i2c_client *client = to_i2c_client(dev); 192 struct lm92_data *data = i2c_get_clientdata(client); 193 long val = simple_strtol(buf, NULL, 10); 194 195 mutex_lock(&data->update_lock); 196 data->temp1_hyst = TEMP_FROM_REG(data->temp1_crit) - val; 197 i2c_smbus_write_word_data(client, LM92_REG_TEMP_HYST, 198 swab16(TEMP_TO_REG(data->temp1_hyst))); 199 mutex_unlock(&data->update_lock); 200 return count; 201 } 202 203 static ssize_t show_alarms(struct device *dev, struct device_attribute *attr, char *buf) 204 { 205 struct lm92_data *data = lm92_update_device(dev); 206 return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp1_input)); 207 } 208 209 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr, 210 char *buf) 211 { 212 int bitnr = to_sensor_dev_attr(attr)->index; 213 struct lm92_data *data = lm92_update_device(dev); 214 return sprintf(buf, "%d\n", (data->temp1_input >> bitnr) & 1); 215 } 216 217 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL); 218 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit, 219 set_temp1_crit); 220 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst, 221 set_temp1_crit_hyst); 222 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min, 223 set_temp1_min); 224 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL); 225 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max, 226 set_temp1_max); 227 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL); 228 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL); 229 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2); 230 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0); 231 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1); 232 233 234 /* 235 * Detection and registration 236 */ 237 238 static void lm92_init_client(struct i2c_client *client) 239 { 240 u8 config; 241 242 /* Start the conversions if needed */ 243 config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG); 244 if (config & 0x01) 245 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG, 246 config & 0xFE); 247 } 248 249 /* The MAX6635 has no identification register, so we have to use tricks 250 to identify it reliably. This is somewhat slow. 251 Note that we do NOT rely on the 2 MSB of the configuration register 252 always reading 0, as suggested by the datasheet, because it was once 253 reported not to be true. */ 254 static int max6635_check(struct i2c_client *client) 255 { 256 u16 temp_low, temp_high, temp_hyst, temp_crit; 257 u8 conf; 258 int i; 259 260 /* No manufacturer ID register, so a read from this address will 261 always return the last read value. */ 262 temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW); 263 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low) 264 return 0; 265 temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH); 266 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high) 267 return 0; 268 269 /* Limits are stored as integer values (signed, 9-bit). */ 270 if ((temp_low & 0x7f00) || (temp_high & 0x7f00)) 271 return 0; 272 temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST); 273 temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT); 274 if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00)) 275 return 0; 276 277 /* Registers addresses were found to cycle over 16-byte boundaries. 278 We don't test all registers with all offsets so as to save some 279 reads and time, but this should still be sufficient to dismiss 280 non-MAX6635 chips. */ 281 conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG); 282 for (i=16; i<96; i*=2) { 283 if (temp_hyst != i2c_smbus_read_word_data(client, 284 LM92_REG_TEMP_HYST + i - 16) 285 || temp_crit != i2c_smbus_read_word_data(client, 286 LM92_REG_TEMP_CRIT + i) 287 || temp_low != i2c_smbus_read_word_data(client, 288 LM92_REG_TEMP_LOW + i + 16) 289 || temp_high != i2c_smbus_read_word_data(client, 290 LM92_REG_TEMP_HIGH + i + 32) 291 || conf != i2c_smbus_read_byte_data(client, 292 LM92_REG_CONFIG + i)) 293 return 0; 294 } 295 296 return 1; 297 } 298 299 static struct attribute *lm92_attributes[] = { 300 &dev_attr_temp1_input.attr, 301 &dev_attr_temp1_crit.attr, 302 &dev_attr_temp1_crit_hyst.attr, 303 &dev_attr_temp1_min.attr, 304 &dev_attr_temp1_min_hyst.attr, 305 &dev_attr_temp1_max.attr, 306 &dev_attr_temp1_max_hyst.attr, 307 &dev_attr_alarms.attr, 308 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr, 309 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr, 310 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, 311 NULL 312 }; 313 314 static const struct attribute_group lm92_group = { 315 .attrs = lm92_attributes, 316 }; 317 318 /* Return 0 if detection is successful, -ENODEV otherwise */ 319 static int lm92_detect(struct i2c_client *new_client, 320 struct i2c_board_info *info) 321 { 322 struct i2c_adapter *adapter = new_client->adapter; 323 u8 config; 324 u16 man_id; 325 326 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA 327 | I2C_FUNC_SMBUS_WORD_DATA)) 328 return -ENODEV; 329 330 config = i2c_smbus_read_byte_data(new_client, LM92_REG_CONFIG); 331 man_id = i2c_smbus_read_word_data(new_client, LM92_REG_MAN_ID); 332 333 if ((config & 0xe0) == 0x00 && man_id == 0x0180) 334 pr_info("lm92: Found National Semiconductor LM92 chip\n"); 335 else if (max6635_check(new_client)) 336 pr_info("lm92: Found Maxim MAX6635 chip\n"); 337 else 338 return -ENODEV; 339 340 strlcpy(info->type, "lm92", I2C_NAME_SIZE); 341 342 return 0; 343 } 344 345 static int lm92_probe(struct i2c_client *new_client, 346 const struct i2c_device_id *id) 347 { 348 struct lm92_data *data; 349 int err; 350 351 data = kzalloc(sizeof(struct lm92_data), GFP_KERNEL); 352 if (!data) { 353 err = -ENOMEM; 354 goto exit; 355 } 356 357 i2c_set_clientdata(new_client, data); 358 data->valid = 0; 359 mutex_init(&data->update_lock); 360 361 /* Initialize the chipset */ 362 lm92_init_client(new_client); 363 364 /* Register sysfs hooks */ 365 if ((err = sysfs_create_group(&new_client->dev.kobj, &lm92_group))) 366 goto exit_free; 367 368 data->hwmon_dev = hwmon_device_register(&new_client->dev); 369 if (IS_ERR(data->hwmon_dev)) { 370 err = PTR_ERR(data->hwmon_dev); 371 goto exit_remove; 372 } 373 374 return 0; 375 376 exit_remove: 377 sysfs_remove_group(&new_client->dev.kobj, &lm92_group); 378 exit_free: 379 kfree(data); 380 exit: 381 return err; 382 } 383 384 static int lm92_remove(struct i2c_client *client) 385 { 386 struct lm92_data *data = i2c_get_clientdata(client); 387 388 hwmon_device_unregister(data->hwmon_dev); 389 sysfs_remove_group(&client->dev.kobj, &lm92_group); 390 391 kfree(data); 392 return 0; 393 } 394 395 396 /* 397 * Module and driver stuff 398 */ 399 400 static const struct i2c_device_id lm92_id[] = { 401 { "lm92", 0 }, 402 /* max6635 could be added here */ 403 { } 404 }; 405 MODULE_DEVICE_TABLE(i2c, lm92_id); 406 407 static struct i2c_driver lm92_driver = { 408 .class = I2C_CLASS_HWMON, 409 .driver = { 410 .name = "lm92", 411 }, 412 .probe = lm92_probe, 413 .remove = lm92_remove, 414 .id_table = lm92_id, 415 .detect = lm92_detect, 416 .address_list = normal_i2c, 417 }; 418 419 static int __init sensors_lm92_init(void) 420 { 421 return i2c_add_driver(&lm92_driver); 422 } 423 424 static void __exit sensors_lm92_exit(void) 425 { 426 i2c_del_driver(&lm92_driver); 427 } 428 429 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); 430 MODULE_DESCRIPTION("LM92/MAX6635 driver"); 431 MODULE_LICENSE("GPL"); 432 433 module_init(sensors_lm92_init); 434 module_exit(sensors_lm92_exit); 435