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/err.h>
  49 #include <linux/mutex.h>
  50
  51 /* The LM92 and MAX6635 have 2 two-state pins for address selection,
  52    resulting in 4 possible addresses. */
  53 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
  54                                        I2C_CLIENT_END };
  55
  56 /* Insmod parameters */
  57 I2C_CLIENT_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). */
  73 static inline int TEMP_FROM_REG(s16 reg)
  74 {
  75         return reg / 8 * 625 / 10;
  76 }
  77
  78 static 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 */
  88 static inline u8 ALARMS_FROM_REG(s16 reg)
  89 {
  90         return reg & 0x0007;
  91 }
  92
  93 /* Driver data (common to all clients) */
  94 static struct i2c_driver lm92_driver;
  95
  96 /* Client data (each client gets its own) */
  97 struct lm92_data {
  98         struct i2c_client client;
  99         struct class_device *class_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 DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL);
 213 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit,
 214         set_temp1_crit);
 215 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst,
 216         set_temp1_crit_hyst);
 217 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min,
 218         set_temp1_min);
 219 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL);
 220 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max,
 221         set_temp1_max);
 222 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL);
 223 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
 224
 225
 226 /*
 227  * Detection and registration
 228  */
 229
 230 static void lm92_init_client(struct i2c_client *client)
 231 {
 232         u8 config;
 233
 234         /* Start the conversions if needed */
 235         config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
 236         if (config & 0x01)
 237                 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
 238                                           config & 0xFE);
 239 }
 240
 241 /* The MAX6635 has no identification register, so we have to use tricks
 242    to identify it reliably. This is somewhat slow.
 243    Note that we do NOT rely on the 2 MSB of the configuration register
 244    always reading 0, as suggested by the datasheet, because it was once
 245    reported not to be true. */
 246 static int max6635_check(struct i2c_client *client)
 247 {
 248         u16 temp_low, temp_high, temp_hyst, temp_crit;
 249         u8 conf;
 250         int i;
 251
 252         /* No manufacturer ID register, so a read from this address will
 253            always return the last read value. */
 254         temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW);
 255         if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low)
 256                 return 0;
 257         temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH);
 258         if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high)
 259                 return 0;
 260
 261         /* Limits are stored as integer values (signed, 9-bit). */
 262         if ((temp_low & 0x7f00) || (temp_high & 0x7f00))
 263                 return 0;
 264         temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST);
 265         temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT);
 266         if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00))
 267                 return 0;
 268
 269         /* Registers addresses were found to cycle over 16-byte boundaries.
 270            We don't test all registers with all offsets so as to save some
 271            reads and time, but this should still be sufficient to dismiss
 272            non-MAX6635 chips. */
 273         conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
 274         for (i=16; i<96; i*=2) {
 275                 if (temp_hyst != i2c_smbus_read_word_data(client,
 276                                  LM92_REG_TEMP_HYST + i - 16)
 277                  || temp_crit != i2c_smbus_read_word_data(client,
 278                                  LM92_REG_TEMP_CRIT + i)
 279                  || temp_low != i2c_smbus_read_word_data(client,
 280                                 LM92_REG_TEMP_LOW + i + 16)
 281                  || temp_high != i2c_smbus_read_word_data(client,
 282                                  LM92_REG_TEMP_HIGH + i + 32)
 283                  || conf != i2c_smbus_read_byte_data(client,
 284                             LM92_REG_CONFIG + i))
 285                         return 0;
 286         }
 287
 288         return 1;
 289 }
 290
 291 static struct attribute *lm92_attributes[] = {
 292         &dev_attr_temp1_input.attr,
 293         &dev_attr_temp1_crit.attr,
 294         &dev_attr_temp1_crit_hyst.attr,
 295         &dev_attr_temp1_min.attr,
 296         &dev_attr_temp1_min_hyst.attr,
 297         &dev_attr_temp1_max.attr,
 298         &dev_attr_temp1_max_hyst.attr,
 299         &dev_attr_alarms.attr,
 300
 301         NULL
 302 };
 303
 304 static const struct attribute_group lm92_group = {
 305         .attrs = lm92_attributes,
 306 };
 307
 308 /* The following function does more than just detection. If detection
 309    succeeds, it also registers the new chip. */
 310 static int lm92_detect(struct i2c_adapter *adapter, int address, int kind)
 311 {
 312         struct i2c_client *new_client;
 313         struct lm92_data *data;
 314         int err = 0;
 315         char *name;
 316
 317         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 318                                             | I2C_FUNC_SMBUS_WORD_DATA))
 319                 goto exit;
 320
 321         if (!(data = kzalloc(sizeof(struct lm92_data), GFP_KERNEL))) {
 322                 err = -ENOMEM;
 323                 goto exit;
 324         }
 325
 326         /* Fill in enough client fields so that we can read from the chip,
 327            which is required for identication */
 328         new_client = &data->client;
 329         i2c_set_clientdata(new_client, data);
 330         new_client->addr = address;
 331         new_client->adapter = adapter;
 332         new_client->driver = &lm92_driver;
 333         new_client->flags = 0;
 334
 335         /* A negative kind means that the driver was loaded with no force
 336            parameter (default), so we must identify the chip. */
 337         if (kind < 0) {
 338                 u8 config = i2c_smbus_read_byte_data(new_client,
 339                              LM92_REG_CONFIG);
 340                 u16 man_id = i2c_smbus_read_word_data(new_client,
 341                              LM92_REG_MAN_ID);
 342
 343                 if ((config & 0xe0) == 0x00
 344                  && man_id == 0x0180) {
 345                         pr_info("lm92: Found National Semiconductor LM92 chip\n");
 346                         kind = lm92;
 347                 } else
 348                 if (max6635_check(new_client)) {
 349                         pr_info("lm92: Found Maxim MAX6635 chip\n");
 350                         kind = lm92; /* No separate prefix */
 351                 }
 352                 else
 353                         goto exit_free;
 354         } else
 355         if (kind == 0) /* Default to an LM92 if forced */
 356                 kind = lm92;
 357
 358         /* Give it the proper name */
 359         if (kind == lm92) {
 360                 name = "lm92";
 361         } else { /* Supposedly cannot happen */
 362                 dev_dbg(&new_client->dev, "Kind out of range?\n");
 363                 goto exit_free;
 364         }
 365
 366         /* Fill in the remaining client fields */
 367         strlcpy(new_client->name, name, I2C_NAME_SIZE);
 368         data->valid = 0;
 369         mutex_init(&data->update_lock);
 370
 371         /* Tell the i2c subsystem a new client has arrived */
 372         if ((err = i2c_attach_client(new_client)))
 373                 goto exit_free;
 374
 375         /* Initialize the chipset */
 376         lm92_init_client(new_client);
 377
 378         /* Register sysfs hooks */
 379         if ((err = sysfs_create_group(&new_client->dev.kobj, &lm92_group)))
 380                 goto exit_detach;
 381
 382         data->class_dev = hwmon_device_register(&new_client->dev);
 383         if (IS_ERR(data->class_dev)) {
 384                 err = PTR_ERR(data->class_dev);
 385                 goto exit_remove;
 386         }
 387
 388         return 0;
 389
 390 exit_remove:
 391         sysfs_remove_group(&new_client->dev.kobj, &lm92_group);
 392 exit_detach:
 393         i2c_detach_client(new_client);
 394 exit_free:
 395         kfree(data);
 396 exit:
 397         return err;
 398 }
 399
 400 static int lm92_attach_adapter(struct i2c_adapter *adapter)
 401 {
 402         if (!(adapter->class & I2C_CLASS_HWMON))
 403                 return 0;
 404         return i2c_probe(adapter, &addr_data, lm92_detect);
 405 }
 406
 407 static int lm92_detach_client(struct i2c_client *client)
 408 {
 409         struct lm92_data *data = i2c_get_clientdata(client);
 410         int err;
 411
 412         hwmon_device_unregister(data->class_dev);
 413         sysfs_remove_group(&client->dev.kobj, &lm92_group);
 414
 415         if ((err = i2c_detach_client(client)))
 416                 return err;
 417
 418         kfree(data);
 419         return 0;
 420 }
 421
 422
 423 /*
 424  * Module and driver stuff
 425  */
 426
 427 static struct i2c_driver lm92_driver = {
 428         .driver = {
 429                 .name   = "lm92",
 430         },
 431         .id             = I2C_DRIVERID_LM92,
 432         .attach_adapter = lm92_attach_adapter,
 433         .detach_client  = lm92_detach_client,
 434 };
 435
 436 static int __init sensors_lm92_init(void)
 437 {
 438         return i2c_add_driver(&lm92_driver);
 439 }
 440
 441 static void __exit sensors_lm92_exit(void)
 442 {
 443         i2c_del_driver(&lm92_driver);
 444 }
 445
 446 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
 447 MODULE_DESCRIPTION("LM92/MAX6635 driver");
 448 MODULE_LICENSE("GPL");
 449
 450 module_init(sensors_lm92_init);
 451 module_exit(sensors_lm92_exit);