lm92.c revision 8d5d45fb14680326f833295f2316a4ec5e357220
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/i2c-sensor.h> 48 49 50/* The LM92 and MAX6635 have 2 two-state pins for address selection, 51 resulting in 4 possible addresses. */ 52static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 53 I2C_CLIENT_END }; 54static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END }; 55 56/* Insmod parameters */ 57SENSORS_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). */ 73static inline int TEMP_FROM_REG(s16 reg) 74{ 75 return reg / 8 * 625 / 10; 76} 77 78static 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 */ 88static inline u8 ALARMS_FROM_REG(s16 reg) 89{ 90 return reg & 0x0007; 91} 92 93/* Driver data (common to all clients) */ 94static struct i2c_driver lm92_driver; 95 96/* Client data (each client gets its own) */ 97struct lm92_data { 98 struct i2c_client client; 99 struct semaphore update_lock; 100 char valid; /* zero until following fields are valid */ 101 unsigned long last_updated; /* in jiffies */ 102 103 /* registers values */ 104 s16 temp1_input, temp1_crit, temp1_min, temp1_max, temp1_hyst; 105}; 106 107 108/* 109 * Sysfs attributes and callback functions 110 */ 111 112static struct lm92_data *lm92_update_device(struct device *dev) 113{ 114 struct i2c_client *client = to_i2c_client(dev); 115 struct lm92_data *data = i2c_get_clientdata(client); 116 117 down(&data->update_lock); 118 119 if (time_after(jiffies, data->last_updated + HZ) 120 || !data->valid) { 121 dev_dbg(&client->dev, "Updating lm92 data\n"); 122 data->temp1_input = swab16(i2c_smbus_read_word_data(client, 123 LM92_REG_TEMP)); 124 data->temp1_hyst = swab16(i2c_smbus_read_word_data(client, 125 LM92_REG_TEMP_HYST)); 126 data->temp1_crit = swab16(i2c_smbus_read_word_data(client, 127 LM92_REG_TEMP_CRIT)); 128 data->temp1_min = swab16(i2c_smbus_read_word_data(client, 129 LM92_REG_TEMP_LOW)); 130 data->temp1_max = swab16(i2c_smbus_read_word_data(client, 131 LM92_REG_TEMP_HIGH)); 132 133 data->last_updated = jiffies; 134 data->valid = 1; 135 } 136 137 up(&data->update_lock); 138 139 return data; 140} 141 142#define show_temp(value) \ 143static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \ 144{ \ 145 struct lm92_data *data = lm92_update_device(dev); \ 146 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->value)); \ 147} 148show_temp(temp1_input); 149show_temp(temp1_crit); 150show_temp(temp1_min); 151show_temp(temp1_max); 152 153#define set_temp(value, reg) \ 154static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, \ 155 size_t count) \ 156{ \ 157 struct i2c_client *client = to_i2c_client(dev); \ 158 struct lm92_data *data = i2c_get_clientdata(client); \ 159 long val = simple_strtol(buf, NULL, 10); \ 160 \ 161 down(&data->update_lock); \ 162 data->value = TEMP_TO_REG(val); \ 163 i2c_smbus_write_word_data(client, reg, swab16(data->value)); \ 164 up(&data->update_lock); \ 165 return count; \ 166} 167set_temp(temp1_crit, LM92_REG_TEMP_CRIT); 168set_temp(temp1_min, LM92_REG_TEMP_LOW); 169set_temp(temp1_max, LM92_REG_TEMP_HIGH); 170 171static ssize_t show_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf) 172{ 173 struct lm92_data *data = lm92_update_device(dev); 174 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_crit) 175 - TEMP_FROM_REG(data->temp1_hyst)); 176} 177static ssize_t show_temp1_max_hyst(struct device *dev, struct device_attribute *attr, char *buf) 178{ 179 struct lm92_data *data = lm92_update_device(dev); 180 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_max) 181 - TEMP_FROM_REG(data->temp1_hyst)); 182} 183static ssize_t show_temp1_min_hyst(struct device *dev, struct device_attribute *attr, char *buf) 184{ 185 struct lm92_data *data = lm92_update_device(dev); 186 return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_min) 187 + TEMP_FROM_REG(data->temp1_hyst)); 188} 189 190static ssize_t set_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf, 191 size_t count) 192{ 193 struct i2c_client *client = to_i2c_client(dev); 194 struct lm92_data *data = i2c_get_clientdata(client); 195 long val = simple_strtol(buf, NULL, 10); 196 197 down(&data->update_lock); 198 data->temp1_hyst = TEMP_FROM_REG(data->temp1_crit) - val; 199 i2c_smbus_write_word_data(client, LM92_REG_TEMP_HYST, 200 swab16(TEMP_TO_REG(data->temp1_hyst))); 201 up(&data->update_lock); 202 return count; 203} 204 205static ssize_t show_alarms(struct device *dev, struct device_attribute *attr, char *buf) 206{ 207 struct lm92_data *data = lm92_update_device(dev); 208 return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp1_input)); 209} 210 211static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL); 212static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit, 213 set_temp1_crit); 214static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst, 215 set_temp1_crit_hyst); 216static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min, 217 set_temp1_min); 218static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL); 219static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max, 220 set_temp1_max); 221static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL); 222static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL); 223 224 225/* 226 * Detection and registration 227 */ 228 229static void lm92_init_client(struct i2c_client *client) 230{ 231 u8 config; 232 233 /* Start the conversions if needed */ 234 config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG); 235 if (config & 0x01) 236 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG, 237 config & 0xFE); 238} 239 240/* The MAX6635 has no identification register, so we have to use tricks 241 to identify it reliably. This is somewhat slow. 242 Note that we do NOT rely on the 2 MSB of the configuration register 243 always reading 0, as suggested by the datasheet, because it was once 244 reported not to be true. */ 245static int max6635_check(struct i2c_client *client) 246{ 247 u16 temp_low, temp_high, temp_hyst, temp_crit; 248 u8 conf; 249 int i; 250 251 /* No manufacturer ID register, so a read from this address will 252 always return the last read value. */ 253 temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW); 254 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low) 255 return 0; 256 temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH); 257 if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high) 258 return 0; 259 260 /* Limits are stored as integer values (signed, 9-bit). */ 261 if ((temp_low & 0x7f00) || (temp_high & 0x7f00)) 262 return 0; 263 temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST); 264 temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT); 265 if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00)) 266 return 0; 267 268 /* Registers addresses were found to cycle over 16-byte boundaries. 269 We don't test all registers with all offsets so as to save some 270 reads and time, but this should still be sufficient to dismiss 271 non-MAX6635 chips. */ 272 conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG); 273 for (i=16; i<96; i*=2) { 274 if (temp_hyst != i2c_smbus_read_word_data(client, 275 LM92_REG_TEMP_HYST + i - 16) 276 || temp_crit != i2c_smbus_read_word_data(client, 277 LM92_REG_TEMP_CRIT + i) 278 || temp_low != i2c_smbus_read_word_data(client, 279 LM92_REG_TEMP_LOW + i + 16) 280 || temp_high != i2c_smbus_read_word_data(client, 281 LM92_REG_TEMP_HIGH + i + 32) 282 || conf != i2c_smbus_read_byte_data(client, 283 LM92_REG_CONFIG + i)) 284 return 0; 285 } 286 287 return 1; 288} 289 290/* The following function does more than just detection. If detection 291 succeeds, it also registers the new chip. */ 292static int lm92_detect(struct i2c_adapter *adapter, int address, int kind) 293{ 294 struct i2c_client *new_client; 295 struct lm92_data *data; 296 int err = 0; 297 char *name; 298 299 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA 300 | I2C_FUNC_SMBUS_WORD_DATA)) 301 goto exit; 302 303 if (!(data = kmalloc(sizeof(struct lm92_data), GFP_KERNEL))) { 304 err = -ENOMEM; 305 goto exit; 306 } 307 memset(data, 0, sizeof(struct lm92_data)); 308 309 /* Fill in enough client fields so that we can read from the chip, 310 which is required for identication */ 311 new_client = &data->client; 312 i2c_set_clientdata(new_client, data); 313 new_client->addr = address; 314 new_client->adapter = adapter; 315 new_client->driver = &lm92_driver; 316 new_client->flags = 0; 317 318 /* A negative kind means that the driver was loaded with no force 319 parameter (default), so we must identify the chip. */ 320 if (kind < 0) { 321 u8 config = i2c_smbus_read_byte_data(new_client, 322 LM92_REG_CONFIG); 323 u16 man_id = i2c_smbus_read_word_data(new_client, 324 LM92_REG_MAN_ID); 325 326 if ((config & 0xe0) == 0x00 327 && man_id == 0x0180) { 328 pr_info("lm92: Found National Semiconductor LM92 chip\n"); 329 kind = lm92; 330 } else 331 if (max6635_check(new_client)) { 332 pr_info("lm92: Found Maxim MAX6635 chip\n"); 333 kind = lm92; /* No separate prefix */ 334 } 335 else 336 goto exit_free; 337 } else 338 if (kind == 0) /* Default to an LM92 if forced */ 339 kind = lm92; 340 341 /* Give it the proper name */ 342 if (kind == lm92) { 343 name = "lm92"; 344 } else { /* Supposedly cannot happen */ 345 dev_dbg(&new_client->dev, "Kind out of range?\n"); 346 goto exit_free; 347 } 348 349 /* Fill in the remaining client fields */ 350 strlcpy(new_client->name, name, I2C_NAME_SIZE); 351 data->valid = 0; 352 init_MUTEX(&data->update_lock); 353 354 /* Tell the i2c subsystem a new client has arrived */ 355 if ((err = i2c_attach_client(new_client))) 356 goto exit_free; 357 358 /* Initialize the chipset */ 359 lm92_init_client(new_client); 360 361 /* Register sysfs hooks */ 362 device_create_file(&new_client->dev, &dev_attr_temp1_input); 363 device_create_file(&new_client->dev, &dev_attr_temp1_crit); 364 device_create_file(&new_client->dev, &dev_attr_temp1_crit_hyst); 365 device_create_file(&new_client->dev, &dev_attr_temp1_min); 366 device_create_file(&new_client->dev, &dev_attr_temp1_min_hyst); 367 device_create_file(&new_client->dev, &dev_attr_temp1_max); 368 device_create_file(&new_client->dev, &dev_attr_temp1_max_hyst); 369 device_create_file(&new_client->dev, &dev_attr_alarms); 370 371 return 0; 372 373exit_free: 374 kfree(data); 375exit: 376 return err; 377} 378 379static int lm92_attach_adapter(struct i2c_adapter *adapter) 380{ 381 if (!(adapter->class & I2C_CLASS_HWMON)) 382 return 0; 383 return i2c_detect(adapter, &addr_data, lm92_detect); 384} 385 386static int lm92_detach_client(struct i2c_client *client) 387{ 388 int err; 389 390 if ((err = i2c_detach_client(client))) { 391 dev_err(&client->dev, "Client deregistration failed, " 392 "client not detached.\n"); 393 return err; 394 } 395 396 kfree(i2c_get_clientdata(client)); 397 return 0; 398} 399 400 401/* 402 * Module and driver stuff 403 */ 404 405static struct i2c_driver lm92_driver = { 406 .owner = THIS_MODULE, 407 .name = "lm92", 408 .id = I2C_DRIVERID_LM92, 409 .flags = I2C_DF_NOTIFY, 410 .attach_adapter = lm92_attach_adapter, 411 .detach_client = lm92_detach_client, 412}; 413 414static int __init sensors_lm92_init(void) 415{ 416 return i2c_add_driver(&lm92_driver); 417} 418 419static void __exit sensors_lm92_exit(void) 420{ 421 i2c_del_driver(&lm92_driver); 422} 423 424MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); 425MODULE_DESCRIPTION("LM92/MAX6635 driver"); 426MODULE_LICENSE("GPL"); 427 428module_init(sensors_lm92_init); 429module_exit(sensors_lm92_exit); 430