drivers/hwmon/lm92.c

   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/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 /* Insmod parameters */
  58 I2C_CLIENT_INSMOD_1(lm92);
  59
  60 /* The LM92 registers */
  61 #define LM92_REG_CONFIG                 0x01 /* 8-bit, RW */
  62 #define LM92_REG_TEMP                   0x00 /* 16-bit, RO */
  63 #define LM92_REG_TEMP_HYST              0x02 /* 16-bit, RW */
  64 #define LM92_REG_TEMP_CRIT              0x03 /* 16-bit, RW */
  65 #define LM92_REG_TEMP_LOW               0x04 /* 16-bit, RW */
  66 #define LM92_REG_TEMP_HIGH              0x05 /* 16-bit, RW */
  67 #define LM92_REG_MAN_ID                 0x07 /* 16-bit, RO, LM92 only */
  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 static inline int TEMP_FROM_REG(s16 reg)
  75 {
  76         return reg / 8 * 625 / 10;
  77 }
  78
  79 static inline s16 TEMP_TO_REG(int val)
  80 {
  81         if (val <= -60000)
  82                 return -60000 * 10 / 625 * 8;
  83         if (val >= 160000)
  84                 return 160000 * 10 / 625 * 8;
  85         return val * 10 / 625 * 8;
  86 }
  87
  88 /* Alarm flags are stored in the 3 LSB of the temperature register */
  89 static inline u8 ALARMS_FROM_REG(s16 reg)
  90 {
  91         return reg & 0x0007;
  92 }
  93
  94 /* Driver data (common to all clients) */
  95 static struct i2c_driver lm92_driver;
  96
  97 /* Client data (each client gets its own) */
  98 struct lm92_data {
  99         struct i2c_client client;
 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 = swab16(i2c_smbus_read_word_data(client,
 125                                     LM92_REG_TEMP));
 126                 data->temp1_hyst = swab16(i2c_smbus_read_word_data(client,
 127                                     LM92_REG_TEMP_HYST));
 128                 data->temp1_crit = swab16(i2c_smbus_read_word_data(client,
 129                                     LM92_REG_TEMP_CRIT));
 130                 data->temp1_min = swab16(i2c_smbus_read_word_data(client,
 131                                     LM92_REG_TEMP_LOW));
 132                 data->temp1_max = swab16(i2c_smbus_read_word_data(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, char *buf) \
 146 { \
 147         struct lm92_data *data = lm92_update_device(dev); \
 148         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->value)); \
 149 }
 150 show_temp(temp1_input);
 151 show_temp(temp1_crit);
 152 show_temp(temp1_min);
 153 show_temp(temp1_max);
 154
 155 #define set_temp(value, reg) \
 156 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, \
 157         size_t count) \
 158 { \
 159         struct i2c_client *client = to_i2c_client(dev); \
 160         struct lm92_data *data = i2c_get_clientdata(client); \
 161         long val = simple_strtol(buf, NULL, 10); \
 162  \
 163         mutex_lock(&data->update_lock); \
 164         data->value = TEMP_TO_REG(val); \
 165         i2c_smbus_write_word_data(client, reg, swab16(data->value)); \
 166         mutex_unlock(&data->update_lock); \
 167         return count; \
 168 }
 169 set_temp(temp1_crit, LM92_REG_TEMP_CRIT);
 170 set_temp(temp1_min, LM92_REG_TEMP_LOW);
 171 set_temp(temp1_max, LM92_REG_TEMP_HIGH);
 172
 173 static ssize_t show_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf)
 174 {
 175         struct lm92_data *data = lm92_update_device(dev);
 176         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_crit)
 177                        - TEMP_FROM_REG(data->temp1_hyst));
 178 }
 179 static ssize_t show_temp1_max_hyst(struct device *dev, 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_max)
 183                        - TEMP_FROM_REG(data->temp1_hyst));
 184 }
 185 static ssize_t show_temp1_min_hyst(struct device *dev, struct device_attribute *attr, char *buf)
 186 {
 187         struct lm92_data *data = lm92_update_device(dev);
 188         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_min)
 189                        + TEMP_FROM_REG(data->temp1_hyst));
 190 }
 191
 192 static ssize_t set_temp1_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf,
 193         size_t count)
 194 {
 195         struct i2c_client *client = to_i2c_client(dev);
 196         struct lm92_data *data = i2c_get_clientdata(client);
 197         long val = simple_strtol(buf, NULL, 10);
 198
 199         mutex_lock(&data->update_lock);
 200         data->temp1_hyst = TEMP_FROM_REG(data->temp1_crit) - val;
 201         i2c_smbus_write_word_data(client, LM92_REG_TEMP_HYST,
 202                                   swab16(TEMP_TO_REG(data->temp1_hyst)));
 203         mutex_unlock(&data->update_lock);
 204         return count;
 205 }
 206
 207 static ssize_t show_alarms(struct device *dev, struct device_attribute *attr, char *buf)
 208 {
 209         struct lm92_data *data = lm92_update_device(dev);
 210         return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp1_input));
 211 }
 212
 213 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
 214                           char *buf)
 215 {
 216         int bitnr = to_sensor_dev_attr(attr)->index;
 217         struct lm92_data *data = lm92_update_device(dev);
 218         return sprintf(buf, "%d\n", (data->temp1_input >> bitnr) & 1);
 219 }
 220
 221 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL);
 222 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit,
 223         set_temp1_crit);
 224 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst,
 225         set_temp1_crit_hyst);
 226 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min,
 227         set_temp1_min);
 228 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL);
 229 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max,
 230         set_temp1_max);
 231 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL);
 232 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
 233 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
 234 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
 235 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);
 236
 237
 238 /*
 239  * Detection and registration
 240  */
 241
 242 static void lm92_init_client(struct i2c_client *client)
 243 {
 244         u8 config;
 245
 246         /* Start the conversions if needed */
 247         config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
 248         if (config & 0x01)
 249                 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
 250                                           config & 0xFE);
 251 }
 252
 253 /* The MAX6635 has no identification register, so we have to use tricks
 254    to identify it reliably. This is somewhat slow.
 255    Note that we do NOT rely on the 2 MSB of the configuration register
 256    always reading 0, as suggested by the datasheet, because it was once
 257    reported not to be true. */
 258 static int max6635_check(struct i2c_client *client)
 259 {
 260         u16 temp_low, temp_high, temp_hyst, temp_crit;
 261         u8 conf;
 262         int i;
 263
 264         /* No manufacturer ID register, so a read from this address will
 265            always return the last read value. */
 266         temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW);
 267         if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low)
 268                 return 0;
 269         temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH);
 270         if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high)
 271                 return 0;
 272
 273         /* Limits are stored as integer values (signed, 9-bit). */
 274         if ((temp_low & 0x7f00) || (temp_high & 0x7f00))
 275                 return 0;
 276         temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST);
 277         temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT);
 278         if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00))
 279                 return 0;
 280
 281         /* Registers addresses were found to cycle over 16-byte boundaries.
 282            We don't test all registers with all offsets so as to save some
 283            reads and time, but this should still be sufficient to dismiss
 284            non-MAX6635 chips. */
 285         conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
 286         for (i=16; i<96; i*=2) {
 287                 if (temp_hyst != i2c_smbus_read_word_data(client,
 288                                  LM92_REG_TEMP_HYST + i - 16)
 289                  || temp_crit != i2c_smbus_read_word_data(client,
 290                                  LM92_REG_TEMP_CRIT + i)
 291                  || temp_low != i2c_smbus_read_word_data(client,
 292                                 LM92_REG_TEMP_LOW + i + 16)
 293                  || temp_high != i2c_smbus_read_word_data(client,
 294                                  LM92_REG_TEMP_HIGH + i + 32)
 295                  || conf != i2c_smbus_read_byte_data(client,
 296                             LM92_REG_CONFIG + i))
 297                         return 0;
 298         }
 299
 300         return 1;
 301 }
 302
 303 static struct attribute *lm92_attributes[] = {
 304         &dev_attr_temp1_input.attr,
 305         &dev_attr_temp1_crit.attr,
 306         &dev_attr_temp1_crit_hyst.attr,
 307         &dev_attr_temp1_min.attr,
 308         &dev_attr_temp1_min_hyst.attr,
 309         &dev_attr_temp1_max.attr,
 310         &dev_attr_temp1_max_hyst.attr,
 311         &dev_attr_alarms.attr,
 312         &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
 313         &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 314         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 315         NULL
 316 };
 317
 318 static const struct attribute_group lm92_group = {
 319         .attrs = lm92_attributes,
 320 };
 321
 322 /* The following function does more than just detection. If detection
 323    succeeds, it also registers the new chip. */
 324 static int lm92_detect(struct i2c_adapter *adapter, int address, int kind)
 325 {
 326         struct i2c_client *new_client;
 327         struct lm92_data *data;
 328         int err = 0;
 329         char *name;
 330
 331         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 332                                             | I2C_FUNC_SMBUS_WORD_DATA))
 333                 goto exit;
 334
 335         if (!(data = kzalloc(sizeof(struct lm92_data), GFP_KERNEL))) {
 336                 err = -ENOMEM;
 337                 goto exit;
 338         }
 339
 340         /* Fill in enough client fields so that we can read from the chip,
 341            which is required for identication */
 342         new_client = &data->client;
 343         i2c_set_clientdata(new_client, data);
 344         new_client->addr = address;
 345         new_client->adapter = adapter;
 346         new_client->driver = &lm92_driver;
 347         new_client->flags = 0;
 348
 349         /* A negative kind means that the driver was loaded with no force
 350            parameter (default), so we must identify the chip. */
 351         if (kind < 0) {
 352                 u8 config = i2c_smbus_read_byte_data(new_client,
 353                              LM92_REG_CONFIG);
 354                 u16 man_id = i2c_smbus_read_word_data(new_client,
 355                              LM92_REG_MAN_ID);
 356
 357                 if ((config & 0xe0) == 0x00
 358                  && man_id == 0x0180) {
 359                         pr_info("lm92: Found National Semiconductor LM92 chip\n");
 360                         kind = lm92;
 361                 } else
 362                 if (max6635_check(new_client)) {
 363                         pr_info("lm92: Found Maxim MAX6635 chip\n");
 364                         kind = lm92; /* No separate prefix */
 365                 }
 366                 else
 367                         goto exit_free;
 368         } else
 369         if (kind == 0) /* Default to an LM92 if forced */
 370                 kind = lm92;
 371
 372         /* Give it the proper name */
 373         if (kind == lm92) {
 374                 name = "lm92";
 375         } else { /* Supposedly cannot happen */
 376                 dev_dbg(&new_client->dev, "Kind out of range?\n");
 377                 goto exit_free;
 378         }
 379
 380         /* Fill in the remaining client fields */
 381         strlcpy(new_client->name, name, I2C_NAME_SIZE);
 382         data->valid = 0;
 383         mutex_init(&data->update_lock);
 384
 385         /* Tell the i2c subsystem a new client has arrived */
 386         if ((err = i2c_attach_client(new_client)))
 387                 goto exit_free;
 388
 389         /* Initialize the chipset */
 390         lm92_init_client(new_client);
 391
 392         /* Register sysfs hooks */
 393         if ((err = sysfs_create_group(&new_client->dev.kobj, &lm92_group)))
 394                 goto exit_detach;
 395
 396         data->hwmon_dev = hwmon_device_register(&new_client->dev);
 397         if (IS_ERR(data->hwmon_dev)) {
 398                 err = PTR_ERR(data->hwmon_dev);
 399                 goto exit_remove;
 400         }
 401
 402         return 0;
 403
 404 exit_remove:
 405         sysfs_remove_group(&new_client->dev.kobj, &lm92_group);
 406 exit_detach:
 407         i2c_detach_client(new_client);
 408 exit_free:
 409         kfree(data);
 410 exit:
 411         return err;
 412 }
 413
 414 static int lm92_attach_adapter(struct i2c_adapter *adapter)
 415 {
 416         if (!(adapter->class & I2C_CLASS_HWMON))
 417                 return 0;
 418         return i2c_probe(adapter, &addr_data, lm92_detect);
 419 }
 420
 421 static int lm92_detach_client(struct i2c_client *client)
 422 {
 423         struct lm92_data *data = i2c_get_clientdata(client);
 424         int err;
 425
 426         hwmon_device_unregister(data->hwmon_dev);
 427         sysfs_remove_group(&client->dev.kobj, &lm92_group);
 428
 429         if ((err = i2c_detach_client(client)))
 430                 return err;
 431
 432         kfree(data);
 433         return 0;
 434 }
 435
 436
 437 /*
 438  * Module and driver stuff
 439  */
 440
 441 static struct i2c_driver lm92_driver = {
 442         .driver = {
 443                 .name   = "lm92",
 444         },
 445         .attach_adapter = lm92_attach_adapter,
 446         .detach_client  = lm92_detach_client,
 447 };
 448
 449 static int __init sensors_lm92_init(void)
 450 {
 451         return i2c_add_driver(&lm92_driver);
 452 }
 453
 454 static void __exit sensors_lm92_exit(void)
 455 {
 456         i2c_del_driver(&lm92_driver);
 457 }
 458
 459 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
 460 MODULE_DESCRIPTION("LM92/MAX6635 driver");
 461 MODULE_LICENSE("GPL");
 462
 463 module_init(sensors_lm92_init);
 464 module_exit(sensors_lm92_exit);