1 /* 2 * lm90.c - Part of lm_sensors, Linux kernel modules for hardware 3 * monitoring 4 * Copyright (C) 2003-2005 Jean Delvare <khali@linux-fr.org> 5 * 6 * Based on the lm83 driver. The LM90 is a sensor chip made by National 7 * Semiconductor. It reports up to two temperatures (its own plus up to 8 * one external one) with a 0.125 deg resolution (1 deg for local 9 * temperature) and a 3-4 deg accuracy. Complete datasheet can be 10 * obtained from National's website at: 11 * http://www.national.com/pf/LM/LM90.html 12 * 13 * This driver also supports the LM89 and LM99, two other sensor chips 14 * made by National Semiconductor. Both have an increased remote 15 * temperature measurement accuracy (1 degree), and the LM99 16 * additionally shifts remote temperatures (measured and limits) by 16 17 * degrees, which allows for higher temperatures measurement. The 18 * driver doesn't handle it since it can be done easily in user-space. 19 * Complete datasheets can be obtained from National's website at: 20 * http://www.national.com/pf/LM/LM89.html 21 * http://www.national.com/pf/LM/LM99.html 22 * Note that there is no way to differentiate between both chips. 23 * 24 * This driver also supports the LM86, another sensor chip made by 25 * National Semiconductor. It is exactly similar to the LM90 except it 26 * has a higher accuracy. 27 * Complete datasheet can be obtained from National's website at: 28 * http://www.national.com/pf/LM/LM86.html 29 * 30 * This driver also supports the ADM1032, a sensor chip made by Analog 31 * Devices. That chip is similar to the LM90, with a few differences 32 * that are not handled by this driver. Complete datasheet can be 33 * obtained from Analog's website at: 34 * http://products.analog.com/products/info.asp?product=ADM1032 35 * Among others, it has a higher accuracy than the LM90, much like the 36 * LM86 does. 37 * 38 * This driver also supports the MAX6657, MAX6658 and MAX6659 sensor 39 * chips made by Maxim. These chips are similar to the LM86. Complete 40 * datasheet can be obtained at Maxim's website at: 41 * http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2578 42 * Note that there is no easy way to differentiate between the three 43 * variants. The extra address and features of the MAX6659 are not 44 * supported by this driver. 45 * 46 * This driver also supports the ADT7461 chip from Analog Devices but 47 * only in its "compatability mode". If an ADT7461 chip is found but 48 * is configured in non-compatible mode (where its temperature 49 * register values are decoded differently) it is ignored by this 50 * driver. Complete datasheet can be obtained from Analog's website 51 * at: 52 * http://products.analog.com/products/info.asp?product=ADT7461 53 * 54 * Since the LM90 was the first chipset supported by this driver, most 55 * comments will refer to this chipset, but are actually general and 56 * concern all supported chipsets, unless mentioned otherwise. 57 * 58 * This program is free software; you can redistribute it and/or modify 59 * it under the terms of the GNU General Public License as published by 60 * the Free Software Foundation; either version 2 of the License, or 61 * (at your option) any later version. 62 * 63 * This program is distributed in the hope that it will be useful, 64 * but WITHOUT ANY WARRANTY; without even the implied warranty of 65 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 66 * GNU General Public License for more details. 67 * 68 * You should have received a copy of the GNU General Public License 69 * along with this program; if not, write to the Free Software 70 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 71 */ 72 73 #include <linux/module.h> 74 #include <linux/init.h> 75 #include <linux/slab.h> 76 #include <linux/jiffies.h> 77 #include <linux/i2c.h> 78 #include <linux/hwmon-sysfs.h> 79 #include <linux/hwmon.h> 80 #include <linux/err.h> 81 82 /* 83 * Addresses to scan 84 * Address is fully defined internally and cannot be changed except for 85 * MAX6659. 86 * LM86, LM89, LM90, LM99, ADM1032, MAX6657 and MAX6658 have address 0x4c. 87 * LM89-1, and LM99-1 have address 0x4d. 88 * MAX6659 can have address 0x4c, 0x4d or 0x4e (unsupported). 89 * ADT7461 always has address 0x4c. 90 */ 91 92 static unsigned short normal_i2c[] = { 0x4c, 0x4d, I2C_CLIENT_END }; 93 94 /* 95 * Insmod parameters 96 */ 97 98 I2C_CLIENT_INSMOD_6(lm90, adm1032, lm99, lm86, max6657, adt7461); 99 100 /* 101 * The LM90 registers 102 */ 103 104 #define LM90_REG_R_MAN_ID 0xFE 105 #define LM90_REG_R_CHIP_ID 0xFF 106 #define LM90_REG_R_CONFIG1 0x03 107 #define LM90_REG_W_CONFIG1 0x09 108 #define LM90_REG_R_CONFIG2 0xBF 109 #define LM90_REG_W_CONFIG2 0xBF 110 #define LM90_REG_R_CONVRATE 0x04 111 #define LM90_REG_W_CONVRATE 0x0A 112 #define LM90_REG_R_STATUS 0x02 113 #define LM90_REG_R_LOCAL_TEMP 0x00 114 #define LM90_REG_R_LOCAL_HIGH 0x05 115 #define LM90_REG_W_LOCAL_HIGH 0x0B 116 #define LM90_REG_R_LOCAL_LOW 0x06 117 #define LM90_REG_W_LOCAL_LOW 0x0C 118 #define LM90_REG_R_LOCAL_CRIT 0x20 119 #define LM90_REG_W_LOCAL_CRIT 0x20 120 #define LM90_REG_R_REMOTE_TEMPH 0x01 121 #define LM90_REG_R_REMOTE_TEMPL 0x10 122 #define LM90_REG_R_REMOTE_OFFSH 0x11 123 #define LM90_REG_W_REMOTE_OFFSH 0x11 124 #define LM90_REG_R_REMOTE_OFFSL 0x12 125 #define LM90_REG_W_REMOTE_OFFSL 0x12 126 #define LM90_REG_R_REMOTE_HIGHH 0x07 127 #define LM90_REG_W_REMOTE_HIGHH 0x0D 128 #define LM90_REG_R_REMOTE_HIGHL 0x13 129 #define LM90_REG_W_REMOTE_HIGHL 0x13 130 #define LM90_REG_R_REMOTE_LOWH 0x08 131 #define LM90_REG_W_REMOTE_LOWH 0x0E 132 #define LM90_REG_R_REMOTE_LOWL 0x14 133 #define LM90_REG_W_REMOTE_LOWL 0x14 134 #define LM90_REG_R_REMOTE_CRIT 0x19 135 #define LM90_REG_W_REMOTE_CRIT 0x19 136 #define LM90_REG_R_TCRIT_HYST 0x21 137 #define LM90_REG_W_TCRIT_HYST 0x21 138 139 /* 140 * Conversions and various macros 141 * For local temperatures and limits, critical limits and the hysteresis 142 * value, the LM90 uses signed 8-bit values with LSB = 1 degree Celsius. 143 * For remote temperatures and limits, it uses signed 11-bit values with 144 * LSB = 0.125 degree Celsius, left-justified in 16-bit registers. 145 */ 146 147 #define TEMP1_FROM_REG(val) ((val) * 1000) 148 #define TEMP1_TO_REG(val) ((val) <= -128000 ? -128 : \ 149 (val) >= 127000 ? 127 : \ 150 (val) < 0 ? ((val) - 500) / 1000 : \ 151 ((val) + 500) / 1000) 152 #define TEMP2_FROM_REG(val) ((val) / 32 * 125) 153 #define TEMP2_TO_REG(val) ((val) <= -128000 ? 0x8000 : \ 154 (val) >= 127875 ? 0x7FE0 : \ 155 (val) < 0 ? ((val) - 62) / 125 * 32 : \ 156 ((val) + 62) / 125 * 32) 157 #define HYST_TO_REG(val) ((val) <= 0 ? 0 : (val) >= 30500 ? 31 : \ 158 ((val) + 500) / 1000) 159 160 /* 161 * ADT7461 is almost identical to LM90 except that attempts to write 162 * values that are outside the range 0 < temp < 127 are treated as 163 * the boundary value. 164 */ 165 166 #define TEMP1_TO_REG_ADT7461(val) ((val) <= 0 ? 0 : \ 167 (val) >= 127000 ? 127 : \ 168 ((val) + 500) / 1000) 169 #define TEMP2_TO_REG_ADT7461(val) ((val) <= 0 ? 0 : \ 170 (val) >= 127750 ? 0x7FC0 : \ 171 ((val) + 125) / 250 * 64) 172 173 /* 174 * Functions declaration 175 */ 176 177 static int lm90_attach_adapter(struct i2c_adapter *adapter); 178 static int lm90_detect(struct i2c_adapter *adapter, int address, 179 int kind); 180 static void lm90_init_client(struct i2c_client *client); 181 static int lm90_detach_client(struct i2c_client *client); 182 static struct lm90_data *lm90_update_device(struct device *dev); 183 184 /* 185 * Driver data (common to all clients) 186 */ 187 188 static struct i2c_driver lm90_driver = { 189 .owner = THIS_MODULE, 190 .name = "lm90", 191 .id = I2C_DRIVERID_LM90, 192 .flags = I2C_DF_NOTIFY, 193 .attach_adapter = lm90_attach_adapter, 194 .detach_client = lm90_detach_client, 195 }; 196 197 /* 198 * Client data (each client gets its own) 199 */ 200 201 struct lm90_data { 202 struct i2c_client client; 203 struct class_device *class_dev; 204 struct semaphore update_lock; 205 char valid; /* zero until following fields are valid */ 206 unsigned long last_updated; /* in jiffies */ 207 int kind; 208 209 /* registers values */ 210 s8 temp8[5]; /* 0: local input 211 1: local low limit 212 2: local high limit 213 3: local critical limit 214 4: remote critical limit */ 215 s16 temp11[3]; /* 0: remote input 216 1: remote low limit 217 2: remote high limit */ 218 u8 temp_hyst; 219 u8 alarms; /* bitvector */ 220 }; 221 222 /* 223 * Sysfs stuff 224 */ 225 226 static ssize_t show_temp8(struct device *dev, struct device_attribute *devattr, 227 char *buf) 228 { 229 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); 230 struct lm90_data *data = lm90_update_device(dev); 231 return sprintf(buf, "%d\n", TEMP1_FROM_REG(data->temp8[attr->index])); 232 } 233 234 static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr, 235 const char *buf, size_t count) 236 { 237 static const u8 reg[4] = { 238 LM90_REG_W_LOCAL_LOW, 239 LM90_REG_W_LOCAL_HIGH, 240 LM90_REG_W_LOCAL_CRIT, 241 LM90_REG_W_REMOTE_CRIT, 242 }; 243 244 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); 245 struct i2c_client *client = to_i2c_client(dev); 246 struct lm90_data *data = i2c_get_clientdata(client); 247 long val = simple_strtol(buf, NULL, 10); 248 int nr = attr->index; 249 250 down(&data->update_lock); 251 if (data->kind == adt7461) 252 data->temp8[nr] = TEMP1_TO_REG_ADT7461(val); 253 else 254 data->temp8[nr] = TEMP1_TO_REG(val); 255 i2c_smbus_write_byte_data(client, reg[nr - 1], data->temp8[nr]); 256 up(&data->update_lock); 257 return count; 258 } 259 260 static ssize_t show_temp11(struct device *dev, struct device_attribute *devattr, 261 char *buf) 262 { 263 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); 264 struct lm90_data *data = lm90_update_device(dev); 265 return sprintf(buf, "%d\n", TEMP2_FROM_REG(data->temp11[attr->index])); 266 } 267 268 static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr, 269 const char *buf, size_t count) 270 { 271 static const u8 reg[4] = { 272 LM90_REG_W_REMOTE_LOWH, 273 LM90_REG_W_REMOTE_LOWL, 274 LM90_REG_W_REMOTE_HIGHH, 275 LM90_REG_W_REMOTE_HIGHL, 276 }; 277 278 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); 279 struct i2c_client *client = to_i2c_client(dev); 280 struct lm90_data *data = i2c_get_clientdata(client); 281 long val = simple_strtol(buf, NULL, 10); 282 int nr = attr->index; 283 284 down(&data->update_lock); 285 if (data->kind == adt7461) 286 data->temp11[nr] = TEMP2_TO_REG_ADT7461(val); 287 else 288 data->temp11[nr] = TEMP2_TO_REG(val); 289 i2c_smbus_write_byte_data(client, reg[(nr - 1) * 2], 290 data->temp11[nr] >> 8); 291 i2c_smbus_write_byte_data(client, reg[(nr - 1) * 2 + 1], 292 data->temp11[nr] & 0xff); 293 up(&data->update_lock); 294 return count; 295 } 296 297 static ssize_t show_temphyst(struct device *dev, struct device_attribute *devattr, 298 char *buf) 299 { 300 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); 301 struct lm90_data *data = lm90_update_device(dev); 302 return sprintf(buf, "%d\n", TEMP1_FROM_REG(data->temp8[attr->index]) 303 - TEMP1_FROM_REG(data->temp_hyst)); 304 } 305 306 static ssize_t set_temphyst(struct device *dev, struct device_attribute *dummy, 307 const char *buf, size_t count) 308 { 309 struct i2c_client *client = to_i2c_client(dev); 310 struct lm90_data *data = i2c_get_clientdata(client); 311 long val = simple_strtol(buf, NULL, 10); 312 long hyst; 313 314 down(&data->update_lock); 315 hyst = TEMP1_FROM_REG(data->temp8[3]) - val; 316 i2c_smbus_write_byte_data(client, LM90_REG_W_TCRIT_HYST, 317 HYST_TO_REG(hyst)); 318 up(&data->update_lock); 319 return count; 320 } 321 322 static ssize_t show_alarms(struct device *dev, struct device_attribute *dummy, 323 char *buf) 324 { 325 struct lm90_data *data = lm90_update_device(dev); 326 return sprintf(buf, "%d\n", data->alarms); 327 } 328 329 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp8, NULL, 0); 330 static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp11, NULL, 0); 331 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp8, 332 set_temp8, 1); 333 static SENSOR_DEVICE_ATTR(temp2_min, S_IWUSR | S_IRUGO, show_temp11, 334 set_temp11, 1); 335 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp8, 336 set_temp8, 2); 337 static SENSOR_DEVICE_ATTR(temp2_max, S_IWUSR | S_IRUGO, show_temp11, 338 set_temp11, 2); 339 static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp8, 340 set_temp8, 3); 341 static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_temp8, 342 set_temp8, 4); 343 static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temphyst, 344 set_temphyst, 3); 345 static SENSOR_DEVICE_ATTR(temp2_crit_hyst, S_IRUGO, show_temphyst, NULL, 4); 346 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL); 347 348 /* 349 * Real code 350 */ 351 352 static int lm90_attach_adapter(struct i2c_adapter *adapter) 353 { 354 if (!(adapter->class & I2C_CLASS_HWMON)) 355 return 0; 356 return i2c_probe(adapter, &addr_data, lm90_detect); 357 } 358 359 /* 360 * The following function does more than just detection. If detection 361 * succeeds, it also registers the new chip. 362 */ 363 static int lm90_detect(struct i2c_adapter *adapter, int address, int kind) 364 { 365 struct i2c_client *new_client; 366 struct lm90_data *data; 367 int err = 0; 368 const char *name = ""; 369 370 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) 371 goto exit; 372 373 if (!(data = kmalloc(sizeof(struct lm90_data), GFP_KERNEL))) { 374 err = -ENOMEM; 375 goto exit; 376 } 377 memset(data, 0, sizeof(struct lm90_data)); 378 379 /* The common I2C client data is placed right before the 380 LM90-specific data. */ 381 new_client = &data->client; 382 i2c_set_clientdata(new_client, data); 383 new_client->addr = address; 384 new_client->adapter = adapter; 385 new_client->driver = &lm90_driver; 386 new_client->flags = 0; 387 388 /* 389 * Now we do the remaining detection. A negative kind means that 390 * the driver was loaded with no force parameter (default), so we 391 * must both detect and identify the chip. A zero kind means that 392 * the driver was loaded with the force parameter, the detection 393 * step shall be skipped. A positive kind means that the driver 394 * was loaded with the force parameter and a given kind of chip is 395 * requested, so both the detection and the identification steps 396 * are skipped. 397 */ 398 399 /* Default to an LM90 if forced */ 400 if (kind == 0) 401 kind = lm90; 402 403 if (kind < 0) { /* detection and identification */ 404 u8 man_id, chip_id, reg_config1, reg_convrate; 405 406 man_id = i2c_smbus_read_byte_data(new_client, 407 LM90_REG_R_MAN_ID); 408 chip_id = i2c_smbus_read_byte_data(new_client, 409 LM90_REG_R_CHIP_ID); 410 reg_config1 = i2c_smbus_read_byte_data(new_client, 411 LM90_REG_R_CONFIG1); 412 reg_convrate = i2c_smbus_read_byte_data(new_client, 413 LM90_REG_R_CONVRATE); 414 415 if (man_id == 0x01) { /* National Semiconductor */ 416 u8 reg_config2; 417 418 reg_config2 = i2c_smbus_read_byte_data(new_client, 419 LM90_REG_R_CONFIG2); 420 421 if ((reg_config1 & 0x2A) == 0x00 422 && (reg_config2 & 0xF8) == 0x00 423 && reg_convrate <= 0x09) { 424 if (address == 0x4C 425 && (chip_id & 0xF0) == 0x20) { /* LM90 */ 426 kind = lm90; 427 } else 428 if ((chip_id & 0xF0) == 0x30) { /* LM89/LM99 */ 429 kind = lm99; 430 } else 431 if (address == 0x4C 432 && (chip_id & 0xF0) == 0x10) { /* LM86 */ 433 kind = lm86; 434 } 435 } 436 } else 437 if (man_id == 0x41) { /* Analog Devices */ 438 if (address == 0x4C 439 && (chip_id & 0xF0) == 0x40 /* ADM1032 */ 440 && (reg_config1 & 0x3F) == 0x00 441 && reg_convrate <= 0x0A) { 442 kind = adm1032; 443 } else 444 if (address == 0x4c 445 && chip_id == 0x51 /* ADT7461 */ 446 && (reg_config1 & 0x1F) == 0x00 /* check compat mode */ 447 && reg_convrate <= 0x0A) { 448 kind = adt7461; 449 } 450 } else 451 if (man_id == 0x4D) { /* Maxim */ 452 /* 453 * The Maxim variants do NOT have a chip_id register. 454 * Reading from that address will return the last read 455 * value, which in our case is those of the man_id 456 * register. Likewise, the config1 register seems to 457 * lack a low nibble, so the value will be those of the 458 * previous read, so in our case those of the man_id 459 * register. 460 */ 461 if (chip_id == man_id 462 && (reg_config1 & 0x1F) == (man_id & 0x0F) 463 && reg_convrate <= 0x09) { 464 kind = max6657; 465 } 466 } 467 468 if (kind <= 0) { /* identification failed */ 469 dev_info(&adapter->dev, 470 "Unsupported chip (man_id=0x%02X, " 471 "chip_id=0x%02X).\n", man_id, chip_id); 472 goto exit_free; 473 } 474 } 475 476 if (kind == lm90) { 477 name = "lm90"; 478 } else if (kind == adm1032) { 479 name = "adm1032"; 480 } else if (kind == lm99) { 481 name = "lm99"; 482 } else if (kind == lm86) { 483 name = "lm86"; 484 } else if (kind == max6657) { 485 name = "max6657"; 486 } else if (kind == adt7461) { 487 name = "adt7461"; 488 } 489 490 /* We can fill in the remaining client fields */ 491 strlcpy(new_client->name, name, I2C_NAME_SIZE); 492 data->valid = 0; 493 data->kind = kind; 494 init_MUTEX(&data->update_lock); 495 496 /* Tell the I2C layer a new client has arrived */ 497 if ((err = i2c_attach_client(new_client))) 498 goto exit_free; 499 500 /* Initialize the LM90 chip */ 501 lm90_init_client(new_client); 502 503 /* Register sysfs hooks */ 504 data->class_dev = hwmon_device_register(&new_client->dev); 505 if (IS_ERR(data->class_dev)) { 506 err = PTR_ERR(data->class_dev); 507 goto exit_detach; 508 } 509 510 device_create_file(&new_client->dev, 511 &sensor_dev_attr_temp1_input.dev_attr); 512 device_create_file(&new_client->dev, 513 &sensor_dev_attr_temp2_input.dev_attr); 514 device_create_file(&new_client->dev, 515 &sensor_dev_attr_temp1_min.dev_attr); 516 device_create_file(&new_client->dev, 517 &sensor_dev_attr_temp2_min.dev_attr); 518 device_create_file(&new_client->dev, 519 &sensor_dev_attr_temp1_max.dev_attr); 520 device_create_file(&new_client->dev, 521 &sensor_dev_attr_temp2_max.dev_attr); 522 device_create_file(&new_client->dev, 523 &sensor_dev_attr_temp1_crit.dev_attr); 524 device_create_file(&new_client->dev, 525 &sensor_dev_attr_temp2_crit.dev_attr); 526 device_create_file(&new_client->dev, 527 &sensor_dev_attr_temp1_crit_hyst.dev_attr); 528 device_create_file(&new_client->dev, 529 &sensor_dev_attr_temp2_crit_hyst.dev_attr); 530 device_create_file(&new_client->dev, &dev_attr_alarms); 531 532 return 0; 533 534 exit_detach: 535 i2c_detach_client(new_client); 536 exit_free: 537 kfree(data); 538 exit: 539 return err; 540 } 541 542 static void lm90_init_client(struct i2c_client *client) 543 { 544 u8 config; 545 546 /* 547 * Start the conversions. 548 */ 549 i2c_smbus_write_byte_data(client, LM90_REG_W_CONVRATE, 550 5); /* 2 Hz */ 551 config = i2c_smbus_read_byte_data(client, LM90_REG_R_CONFIG1); 552 if (config & 0x40) 553 i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1, 554 config & 0xBF); /* run */ 555 } 556 557 static int lm90_detach_client(struct i2c_client *client) 558 { 559 struct lm90_data *data = i2c_get_clientdata(client); 560 int err; 561 562 hwmon_device_unregister(data->class_dev); 563 564 if ((err = i2c_detach_client(client))) 565 return err; 566 567 kfree(data); 568 return 0; 569 } 570 571 static struct lm90_data *lm90_update_device(struct device *dev) 572 { 573 struct i2c_client *client = to_i2c_client(dev); 574 struct lm90_data *data = i2c_get_clientdata(client); 575 576 down(&data->update_lock); 577 578 if (time_after(jiffies, data->last_updated + HZ * 2) || !data->valid) { 579 u8 oldh, newh; 580 581 dev_dbg(&client->dev, "Updating lm90 data.\n"); 582 data->temp8[0] = i2c_smbus_read_byte_data(client, 583 LM90_REG_R_LOCAL_TEMP); 584 data->temp8[1] = i2c_smbus_read_byte_data(client, 585 LM90_REG_R_LOCAL_LOW); 586 data->temp8[2] = i2c_smbus_read_byte_data(client, 587 LM90_REG_R_LOCAL_HIGH); 588 data->temp8[3] = i2c_smbus_read_byte_data(client, 589 LM90_REG_R_LOCAL_CRIT); 590 data->temp8[4] = i2c_smbus_read_byte_data(client, 591 LM90_REG_R_REMOTE_CRIT); 592 data->temp_hyst = i2c_smbus_read_byte_data(client, 593 LM90_REG_R_TCRIT_HYST); 594 595 /* 596 * There is a trick here. We have to read two registers to 597 * have the remote sensor temperature, but we have to beware 598 * a conversion could occur inbetween the readings. The 599 * datasheet says we should either use the one-shot 600 * conversion register, which we don't want to do (disables 601 * hardware monitoring) or monitor the busy bit, which is 602 * impossible (we can't read the values and monitor that bit 603 * at the exact same time). So the solution used here is to 604 * read the high byte once, then the low byte, then the high 605 * byte again. If the new high byte matches the old one, 606 * then we have a valid reading. Else we have to read the low 607 * byte again, and now we believe we have a correct reading. 608 */ 609 oldh = i2c_smbus_read_byte_data(client, 610 LM90_REG_R_REMOTE_TEMPH); 611 data->temp11[0] = i2c_smbus_read_byte_data(client, 612 LM90_REG_R_REMOTE_TEMPL); 613 newh = i2c_smbus_read_byte_data(client, 614 LM90_REG_R_REMOTE_TEMPH); 615 if (newh != oldh) { 616 data->temp11[0] = i2c_smbus_read_byte_data(client, 617 LM90_REG_R_REMOTE_TEMPL); 618 #ifdef DEBUG 619 oldh = i2c_smbus_read_byte_data(client, 620 LM90_REG_R_REMOTE_TEMPH); 621 /* oldh is actually newer */ 622 if (newh != oldh) 623 dev_warn(&client->dev, "Remote temperature may be " 624 "wrong.\n"); 625 #endif 626 } 627 data->temp11[0] |= (newh << 8); 628 629 data->temp11[1] = (i2c_smbus_read_byte_data(client, 630 LM90_REG_R_REMOTE_LOWH) << 8) + 631 i2c_smbus_read_byte_data(client, 632 LM90_REG_R_REMOTE_LOWL); 633 data->temp11[2] = (i2c_smbus_read_byte_data(client, 634 LM90_REG_R_REMOTE_HIGHH) << 8) + 635 i2c_smbus_read_byte_data(client, 636 LM90_REG_R_REMOTE_HIGHL); 637 data->alarms = i2c_smbus_read_byte_data(client, 638 LM90_REG_R_STATUS); 639 640 data->last_updated = jiffies; 641 data->valid = 1; 642 } 643 644 up(&data->update_lock); 645 646 return data; 647 } 648 649 static int __init sensors_lm90_init(void) 650 { 651 return i2c_add_driver(&lm90_driver); 652 } 653 654 static void __exit sensors_lm90_exit(void) 655 { 656 i2c_del_driver(&lm90_driver); 657 } 658 659 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); 660 MODULE_DESCRIPTION("LM90/ADM1032 driver"); 661 MODULE_LICENSE("GPL"); 662 663 module_init(sensors_lm90_init); 664 module_exit(sensors_lm90_exit); 665