drivers/hwmon/lm90.c

   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/i2c-sensor.h>
  79 #include <linux/hwmon-sysfs.h>
  80 #include <linux/hwmon.h>
  81 #include <linux/err.h>
  82
  83 /*
  84  * Addresses to scan
  85  * Address is fully defined internally and cannot be changed except for
  86  * MAX6659.
  87  * LM86, LM89, LM90, LM99, ADM1032, MAX6657 and MAX6658 have address 0x4c.
  88  * LM89-1, and LM99-1 have address 0x4d.
  89  * MAX6659 can have address 0x4c, 0x4d or 0x4e (unsupported).
  90  * ADT7461 always has address 0x4c.
  91  */
  92
  93 static unsigned short normal_i2c[] = { 0x4c, 0x4d, I2C_CLIENT_END };
  94
  95 /*
  96  * Insmod parameters
  97  */
  98
  99 SENSORS_INSMOD_6(lm90, adm1032, lm99, lm86, max6657, adt7461);
 100
 101 /*
 102  * The LM90 registers
 103  */
 104
 105 #define LM90_REG_R_MAN_ID               0xFE
 106 #define LM90_REG_R_CHIP_ID              0xFF
 107 #define LM90_REG_R_CONFIG1              0x03
 108 #define LM90_REG_W_CONFIG1              0x09
 109 #define LM90_REG_R_CONFIG2              0xBF
 110 #define LM90_REG_W_CONFIG2              0xBF
 111 #define LM90_REG_R_CONVRATE             0x04
 112 #define LM90_REG_W_CONVRATE             0x0A
 113 #define LM90_REG_R_STATUS               0x02
 114 #define LM90_REG_R_LOCAL_TEMP           0x00
 115 #define LM90_REG_R_LOCAL_HIGH           0x05
 116 #define LM90_REG_W_LOCAL_HIGH           0x0B
 117 #define LM90_REG_R_LOCAL_LOW            0x06
 118 #define LM90_REG_W_LOCAL_LOW            0x0C
 119 #define LM90_REG_R_LOCAL_CRIT           0x20
 120 #define LM90_REG_W_LOCAL_CRIT           0x20
 121 #define LM90_REG_R_REMOTE_TEMPH         0x01
 122 #define LM90_REG_R_REMOTE_TEMPL         0x10
 123 #define LM90_REG_R_REMOTE_OFFSH         0x11
 124 #define LM90_REG_W_REMOTE_OFFSH         0x11
 125 #define LM90_REG_R_REMOTE_OFFSL         0x12
 126 #define LM90_REG_W_REMOTE_OFFSL         0x12
 127 #define LM90_REG_R_REMOTE_HIGHH         0x07
 128 #define LM90_REG_W_REMOTE_HIGHH         0x0D
 129 #define LM90_REG_R_REMOTE_HIGHL         0x13
 130 #define LM90_REG_W_REMOTE_HIGHL         0x13
 131 #define LM90_REG_R_REMOTE_LOWH          0x08
 132 #define LM90_REG_W_REMOTE_LOWH          0x0E
 133 #define LM90_REG_R_REMOTE_LOWL          0x14
 134 #define LM90_REG_W_REMOTE_LOWL          0x14
 135 #define LM90_REG_R_REMOTE_CRIT          0x19
 136 #define LM90_REG_W_REMOTE_CRIT          0x19
 137 #define LM90_REG_R_TCRIT_HYST           0x21
 138 #define LM90_REG_W_TCRIT_HYST           0x21
 139
 140 /*
 141  * Conversions and various macros
 142  * For local temperatures and limits, critical limits and the hysteresis
 143  * value, the LM90 uses signed 8-bit values with LSB = 1 degree Celsius.
 144  * For remote temperatures and limits, it uses signed 11-bit values with
 145  * LSB = 0.125 degree Celsius, left-justified in 16-bit registers.
 146  */
 147
 148 #define TEMP1_FROM_REG(val)     ((val) * 1000)
 149 #define TEMP1_TO_REG(val)       ((val) <= -128000 ? -128 : \
 150                                  (val) >= 127000 ? 127 : \
 151                                  (val) < 0 ? ((val) - 500) / 1000 : \
 152                                  ((val) + 500) / 1000)
 153 #define TEMP2_FROM_REG(val)     ((val) / 32 * 125)
 154 #define TEMP2_TO_REG(val)       ((val) <= -128000 ? 0x8000 : \
 155                                  (val) >= 127875 ? 0x7FE0 : \
 156                                  (val) < 0 ? ((val) - 62) / 125 * 32 : \
 157                                  ((val) + 62) / 125 * 32)
 158 #define HYST_TO_REG(val)        ((val) <= 0 ? 0 : (val) >= 30500 ? 31 : \
 159                                  ((val) + 500) / 1000)
 160
 161 /*
 162  * ADT7461 is almost identical to LM90 except that attempts to write
 163  * values that are outside the range 0 < temp < 127 are treated as
 164  * the boundary value.
 165  */
 166
 167 #define TEMP1_TO_REG_ADT7461(val) ((val) <= 0 ? 0 : \
 168                                  (val) >= 127000 ? 127 : \
 169                                  ((val) + 500) / 1000)
 170 #define TEMP2_TO_REG_ADT7461(val) ((val) <= 0 ? 0 : \
 171                                  (val) >= 127750 ? 0x7FC0 : \
 172                                  ((val) + 125) / 250 * 64)
 173
 174 /*
 175  * Functions declaration
 176  */
 177
 178 static int lm90_attach_adapter(struct i2c_adapter *adapter);
 179 static int lm90_detect(struct i2c_adapter *adapter, int address,
 180         int kind);
 181 static void lm90_init_client(struct i2c_client *client);
 182 static int lm90_detach_client(struct i2c_client *client);
 183 static struct lm90_data *lm90_update_device(struct device *dev);
 184
 185 /*
 186  * Driver data (common to all clients)
 187  */
 188
 189 static struct i2c_driver lm90_driver = {
 190         .owner          = THIS_MODULE,
 191         .name           = "lm90",
 192         .id             = I2C_DRIVERID_LM90,
 193         .flags          = I2C_DF_NOTIFY,
 194         .attach_adapter = lm90_attach_adapter,
 195         .detach_client  = lm90_detach_client,
 196 };
 197
 198 /*
 199  * Client data (each client gets its own)
 200  */
 201
 202 struct lm90_data {
 203         struct i2c_client client;
 204         struct class_device *class_dev;
 205         struct semaphore update_lock;
 206         char valid; /* zero until following fields are valid */
 207         unsigned long last_updated; /* in jiffies */
 208         int kind;
 209
 210         /* registers values */
 211         s8 temp8[5];    /* 0: local input
 212                            1: local low limit
 213                            2: local high limit
 214                            3: local critical limit
 215                            4: remote critical limit */
 216         s16 temp11[3];  /* 0: remote input
 217                            1: remote low limit
 218                            2: remote high limit */
 219         u8 temp_hyst;
 220         u8 alarms; /* bitvector */
 221 };
 222
 223 /*
 224  * Sysfs stuff
 225  */
 226
 227 static ssize_t show_temp8(struct device *dev, struct device_attribute *devattr,
 228                           char *buf)
 229 {
 230         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 231         struct lm90_data *data = lm90_update_device(dev);
 232         return sprintf(buf, "%d\n", TEMP1_FROM_REG(data->temp8[attr->index]));
 233 }
 234
 235 static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
 236                          const char *buf, size_t count)
 237 {
 238         static const u8 reg[4] = {
 239                 LM90_REG_W_LOCAL_LOW,
 240                 LM90_REG_W_LOCAL_HIGH,
 241                 LM90_REG_W_LOCAL_CRIT,
 242                 LM90_REG_W_REMOTE_CRIT,
 243         };
 244
 245         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 246         struct i2c_client *client = to_i2c_client(dev);
 247         struct lm90_data *data = i2c_get_clientdata(client);
 248         long val = simple_strtol(buf, NULL, 10);
 249         int nr = attr->index;
 250
 251         down(&data->update_lock);
 252         if (data->kind == adt7461)
 253                 data->temp8[nr] = TEMP1_TO_REG_ADT7461(val);
 254         else
 255                 data->temp8[nr] = TEMP1_TO_REG(val);
 256         i2c_smbus_write_byte_data(client, reg[nr - 1], data->temp8[nr]);
 257         up(&data->update_lock);
 258         return count;
 259 }
 260
 261 static ssize_t show_temp11(struct device *dev, struct device_attribute *devattr,
 262                            char *buf)
 263 {
 264         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 265         struct lm90_data *data = lm90_update_device(dev);
 266         return sprintf(buf, "%d\n", TEMP2_FROM_REG(data->temp11[attr->index]));
 267 }
 268
 269 static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
 270                           const char *buf, size_t count)
 271 {
 272         static const u8 reg[4] = {
 273                 LM90_REG_W_REMOTE_LOWH,
 274                 LM90_REG_W_REMOTE_LOWL,
 275                 LM90_REG_W_REMOTE_HIGHH,
 276                 LM90_REG_W_REMOTE_HIGHL,
 277         };
 278
 279         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 280         struct i2c_client *client = to_i2c_client(dev);
 281         struct lm90_data *data = i2c_get_clientdata(client);
 282         long val = simple_strtol(buf, NULL, 10);
 283         int nr = attr->index;
 284
 285         down(&data->update_lock);
 286         if (data->kind == adt7461)
 287                 data->temp11[nr] = TEMP2_TO_REG_ADT7461(val);
 288         else
 289                 data->temp11[nr] = TEMP2_TO_REG(val);
 290         i2c_smbus_write_byte_data(client, reg[(nr - 1) * 2],
 291                                   data->temp11[nr] >> 8);
 292         i2c_smbus_write_byte_data(client, reg[(nr - 1) * 2 + 1],
 293                                   data->temp11[nr] & 0xff);
 294         up(&data->update_lock);
 295         return count;
 296 }
 297
 298 static ssize_t show_temphyst(struct device *dev, struct device_attribute *devattr,
 299                              char *buf)
 300 {
 301         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 302         struct lm90_data *data = lm90_update_device(dev);
 303         return sprintf(buf, "%d\n", TEMP1_FROM_REG(data->temp8[attr->index])
 304                        - TEMP1_FROM_REG(data->temp_hyst));
 305 }
 306
 307 static ssize_t set_temphyst(struct device *dev, struct device_attribute *dummy,
 308                             const char *buf, size_t count)
 309 {
 310         struct i2c_client *client = to_i2c_client(dev);
 311         struct lm90_data *data = i2c_get_clientdata(client);
 312         long val = simple_strtol(buf, NULL, 10);
 313         long hyst;
 314
 315         down(&data->update_lock);
 316         hyst = TEMP1_FROM_REG(data->temp8[3]) - val;
 317         i2c_smbus_write_byte_data(client, LM90_REG_W_TCRIT_HYST,
 318                                   HYST_TO_REG(hyst));
 319         up(&data->update_lock);
 320         return count;
 321 }
 322
 323 static ssize_t show_alarms(struct device *dev, struct device_attribute *dummy,
 324                            char *buf)
 325 {
 326         struct lm90_data *data = lm90_update_device(dev);
 327         return sprintf(buf, "%d\n", data->alarms);
 328 }
 329
 330 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp8, NULL, 0);
 331 static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp11, NULL, 0);
 332 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp8,
 333         set_temp8, 1);
 334 static SENSOR_DEVICE_ATTR(temp2_min, S_IWUSR | S_IRUGO, show_temp11,
 335         set_temp11, 1);
 336 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp8,
 337         set_temp8, 2);
 338 static SENSOR_DEVICE_ATTR(temp2_max, S_IWUSR | S_IRUGO, show_temp11,
 339         set_temp11, 2);
 340 static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp8,
 341         set_temp8, 3);
 342 static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_temp8,
 343         set_temp8, 4);
 344 static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temphyst,
 345         set_temphyst, 3);
 346 static SENSOR_DEVICE_ATTR(temp2_crit_hyst, S_IRUGO, show_temphyst, NULL, 4);
 347 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
 348
 349 /*
 350  * Real code
 351  */
 352
 353 static int lm90_attach_adapter(struct i2c_adapter *adapter)
 354 {
 355         if (!(adapter->class & I2C_CLASS_HWMON))
 356                 return 0;
 357         return i2c_detect(adapter, &addr_data, lm90_detect);
 358 }
 359
 360 /*
 361  * The following function does more than just detection. If detection
 362  * succeeds, it also registers the new chip.
 363  */
 364 static int lm90_detect(struct i2c_adapter *adapter, int address, int kind)
 365 {
 366         struct i2c_client *new_client;
 367         struct lm90_data *data;
 368         int err = 0;
 369         const char *name = "";
 370
 371         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 372                 goto exit;
 373
 374         if (!(data = kmalloc(sizeof(struct lm90_data), GFP_KERNEL))) {
 375                 err = -ENOMEM;
 376                 goto exit;
 377         }
 378         memset(data, 0, sizeof(struct lm90_data));
 379
 380         /* The common I2C client data is placed right before the
 381            LM90-specific data. */
 382         new_client = &data->client;
 383         i2c_set_clientdata(new_client, data);
 384         new_client->addr = address;
 385         new_client->adapter = adapter;
 386         new_client->driver = &lm90_driver;
 387         new_client->flags = 0;
 388
 389         /*
 390          * Now we do the remaining detection. A negative kind means that
 391          * the driver was loaded with no force parameter (default), so we
 392          * must both detect and identify the chip. A zero kind means that
 393          * the driver was loaded with the force parameter, the detection
 394          * step shall be skipped. A positive kind means that the driver
 395          * was loaded with the force parameter and a given kind of chip is
 396          * requested, so both the detection and the identification steps
 397          * are skipped.
 398          */
 399
 400         /* Default to an LM90 if forced */
 401         if (kind == 0)
 402                 kind = lm90;
 403
 404         if (kind < 0) { /* detection and identification */
 405                 u8 man_id, chip_id, reg_config1, reg_convrate;
 406
 407                 man_id = i2c_smbus_read_byte_data(new_client,
 408                          LM90_REG_R_MAN_ID);
 409                 chip_id = i2c_smbus_read_byte_data(new_client,
 410                           LM90_REG_R_CHIP_ID);
 411                 reg_config1 = i2c_smbus_read_byte_data(new_client,
 412                               LM90_REG_R_CONFIG1);
 413                 reg_convrate = i2c_smbus_read_byte_data(new_client,
 414                                LM90_REG_R_CONVRATE);
 415
 416                 if (man_id == 0x01) { /* National Semiconductor */
 417                         u8 reg_config2;
 418
 419                         reg_config2 = i2c_smbus_read_byte_data(new_client,
 420                                       LM90_REG_R_CONFIG2);
 421
 422                         if ((reg_config1 & 0x2A) == 0x00
 423                          && (reg_config2 & 0xF8) == 0x00
 424                          && reg_convrate <= 0x09) {
 425                                 if (address == 0x4C
 426                                  && (chip_id & 0xF0) == 0x20) { /* LM90 */
 427                                         kind = lm90;
 428                                 } else
 429                                 if ((chip_id & 0xF0) == 0x30) { /* LM89/LM99 */
 430                                         kind = lm99;
 431                                 } else
 432                                 if (address == 0x4C
 433                                  && (chip_id & 0xF0) == 0x10) { /* LM86 */
 434                                         kind = lm86;
 435                                 }
 436                         }
 437                 } else
 438                 if (man_id == 0x41) { /* Analog Devices */
 439                         if (address == 0x4C
 440                          && (chip_id & 0xF0) == 0x40 /* ADM1032 */
 441                          && (reg_config1 & 0x3F) == 0x00
 442                          && reg_convrate <= 0x0A) {
 443                                 kind = adm1032;
 444                         } else
 445                         if (address == 0x4c
 446                          && chip_id == 0x51 /* ADT7461 */
 447                          && (reg_config1 & 0x1F) == 0x00 /* check compat mode */
 448                          && reg_convrate <= 0x0A) {
 449                                 kind = adt7461;
 450                         }
 451                 } else
 452                 if (man_id == 0x4D) { /* Maxim */
 453                         /*
 454                          * The Maxim variants do NOT have a chip_id register.
 455                          * Reading from that address will return the last read
 456                          * value, which in our case is those of the man_id
 457                          * register. Likewise, the config1 register seems to
 458                          * lack a low nibble, so the value will be those of the
 459                          * previous read, so in our case those of the man_id
 460                          * register.
 461                          */
 462                         if (chip_id == man_id
 463                          && (reg_config1 & 0x1F) == (man_id & 0x0F)
 464                          && reg_convrate <= 0x09) {
 465                                 kind = max6657;
 466                         }
 467                 }
 468
 469                 if (kind <= 0) { /* identification failed */
 470                         dev_info(&adapter->dev,
 471                             "Unsupported chip (man_id=0x%02X, "
 472                             "chip_id=0x%02X).\n", man_id, chip_id);
 473                         goto exit_free;
 474                 }
 475         }
 476
 477         if (kind == lm90) {
 478                 name = "lm90";
 479         } else if (kind == adm1032) {
 480                 name = "adm1032";
 481         } else if (kind == lm99) {
 482                 name = "lm99";
 483         } else if (kind == lm86) {
 484                 name = "lm86";
 485         } else if (kind == max6657) {
 486                 name = "max6657";
 487         } else if (kind == adt7461) {
 488                 name = "adt7461";
 489         }
 490
 491         /* We can fill in the remaining client fields */
 492         strlcpy(new_client->name, name, I2C_NAME_SIZE);
 493         data->valid = 0;
 494         data->kind = kind;
 495         init_MUTEX(&data->update_lock);
 496
 497         /* Tell the I2C layer a new client has arrived */
 498         if ((err = i2c_attach_client(new_client)))
 499                 goto exit_free;
 500
 501         /* Initialize the LM90 chip */
 502         lm90_init_client(new_client);
 503
 504         /* Register sysfs hooks */
 505         data->class_dev = hwmon_device_register(&new_client->dev);
 506         if (IS_ERR(data->class_dev)) {
 507                 err = PTR_ERR(data->class_dev);
 508                 goto exit_detach;
 509         }
 510
 511         device_create_file(&new_client->dev,
 512                            &sensor_dev_attr_temp1_input.dev_attr);
 513         device_create_file(&new_client->dev,
 514                            &sensor_dev_attr_temp2_input.dev_attr);
 515         device_create_file(&new_client->dev,
 516                            &sensor_dev_attr_temp1_min.dev_attr);
 517         device_create_file(&new_client->dev,
 518                            &sensor_dev_attr_temp2_min.dev_attr);
 519         device_create_file(&new_client->dev,
 520                            &sensor_dev_attr_temp1_max.dev_attr);
 521         device_create_file(&new_client->dev,
 522                            &sensor_dev_attr_temp2_max.dev_attr);
 523         device_create_file(&new_client->dev,
 524                            &sensor_dev_attr_temp1_crit.dev_attr);
 525         device_create_file(&new_client->dev,
 526                            &sensor_dev_attr_temp2_crit.dev_attr);
 527         device_create_file(&new_client->dev,
 528                            &sensor_dev_attr_temp1_crit_hyst.dev_attr);
 529         device_create_file(&new_client->dev,
 530                            &sensor_dev_attr_temp2_crit_hyst.dev_attr);
 531         device_create_file(&new_client->dev, &dev_attr_alarms);
 532
 533         return 0;
 534
 535 exit_detach:
 536         i2c_detach_client(new_client);
 537 exit_free:
 538         kfree(data);
 539 exit:
 540         return err;
 541 }
 542
 543 static void lm90_init_client(struct i2c_client *client)
 544 {
 545         u8 config;
 546
 547         /*
 548          * Start the conversions.
 549          */
 550         i2c_smbus_write_byte_data(client, LM90_REG_W_CONVRATE,
 551                                   5); /* 2 Hz */
 552         config = i2c_smbus_read_byte_data(client, LM90_REG_R_CONFIG1);
 553         if (config & 0x40)
 554                 i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
 555                                           config & 0xBF); /* run */
 556 }
 557
 558 static int lm90_detach_client(struct i2c_client *client)
 559 {
 560         struct lm90_data *data = i2c_get_clientdata(client);
 561         int err;
 562
 563         hwmon_device_unregister(data->class_dev);
 564
 565         if ((err = i2c_detach_client(client)))
 566                 return err;
 567
 568         kfree(data);
 569         return 0;
 570 }
 571
 572 static struct lm90_data *lm90_update_device(struct device *dev)
 573 {
 574         struct i2c_client *client = to_i2c_client(dev);
 575         struct lm90_data *data = i2c_get_clientdata(client);
 576
 577         down(&data->update_lock);
 578
 579         if (time_after(jiffies, data->last_updated + HZ * 2) || !data->valid) {
 580                 u8 oldh, newh;
 581
 582                 dev_dbg(&client->dev, "Updating lm90 data.\n");
 583                 data->temp8[0] = i2c_smbus_read_byte_data(client,
 584                                  LM90_REG_R_LOCAL_TEMP);
 585                 data->temp8[1] = i2c_smbus_read_byte_data(client,
 586                                  LM90_REG_R_LOCAL_LOW);
 587                 data->temp8[2] = i2c_smbus_read_byte_data(client,
 588                                  LM90_REG_R_LOCAL_HIGH);
 589                 data->temp8[3] = i2c_smbus_read_byte_data(client,
 590                                  LM90_REG_R_LOCAL_CRIT);
 591                 data->temp8[4] = i2c_smbus_read_byte_data(client,
 592                                  LM90_REG_R_REMOTE_CRIT);
 593                 data->temp_hyst = i2c_smbus_read_byte_data(client,
 594                                   LM90_REG_R_TCRIT_HYST);
 595
 596                 /*
 597                  * There is a trick here. We have to read two registers to
 598                  * have the remote sensor temperature, but we have to beware
 599                  * a conversion could occur inbetween the readings. The
 600                  * datasheet says we should either use the one-shot
 601                  * conversion register, which we don't want to do (disables
 602                  * hardware monitoring) or monitor the busy bit, which is
 603                  * impossible (we can't read the values and monitor that bit
 604                  * at the exact same time). So the solution used here is to
 605                  * read the high byte once, then the low byte, then the high
 606                  * byte again. If the new high byte matches the old one,
 607                  * then we have a valid reading. Else we have to read the low
 608                  * byte again, and now we believe we have a correct reading.
 609                  */
 610                 oldh = i2c_smbus_read_byte_data(client,
 611                        LM90_REG_R_REMOTE_TEMPH);
 612                 data->temp11[0] = i2c_smbus_read_byte_data(client,
 613                                   LM90_REG_R_REMOTE_TEMPL);
 614                 newh = i2c_smbus_read_byte_data(client,
 615                        LM90_REG_R_REMOTE_TEMPH);
 616                 if (newh != oldh) {
 617                         data->temp11[0] = i2c_smbus_read_byte_data(client,
 618                                           LM90_REG_R_REMOTE_TEMPL);
 619 #ifdef DEBUG
 620                         oldh = i2c_smbus_read_byte_data(client,
 621                                LM90_REG_R_REMOTE_TEMPH);
 622                         /* oldh is actually newer */
 623                         if (newh != oldh)
 624                                 dev_warn(&client->dev, "Remote temperature may be "
 625                                          "wrong.\n");
 626 #endif
 627                 }
 628                 data->temp11[0] |= (newh << 8);
 629
 630                 data->temp11[1] = (i2c_smbus_read_byte_data(client,
 631                                    LM90_REG_R_REMOTE_LOWH) << 8) +
 632                                    i2c_smbus_read_byte_data(client,
 633                                    LM90_REG_R_REMOTE_LOWL);
 634                 data->temp11[2] = (i2c_smbus_read_byte_data(client,
 635                                    LM90_REG_R_REMOTE_HIGHH) << 8) +
 636                                    i2c_smbus_read_byte_data(client,
 637                                    LM90_REG_R_REMOTE_HIGHL);
 638                 data->alarms = i2c_smbus_read_byte_data(client,
 639                                LM90_REG_R_STATUS);
 640
 641                 data->last_updated = jiffies;
 642                 data->valid = 1;
 643         }
 644
 645         up(&data->update_lock);
 646
 647         return data;
 648 }
 649
 650 static int __init sensors_lm90_init(void)
 651 {
 652         return i2c_add_driver(&lm90_driver);
 653 }
 654
 655 static void __exit sensors_lm90_exit(void)
 656 {
 657         i2c_del_driver(&lm90_driver);
 658 }
 659
 660 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
 661 MODULE_DESCRIPTION("LM90/ADM1032 driver");
 662 MODULE_LICENSE("GPL");
 663
 664 module_init(sensors_lm90_init);
 665 module_exit(sensors_lm90_exit);