drivers/hwmon/lm92.c

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