drivers/i2c/chips/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/i2c-sensor.h>
  48
  49
  50 /* The LM92 and MAX6635 have 2 two-state pins for address selection,
  51    resulting in 4 possible addresses. */
  52 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
  53                                        I2C_CLIENT_END };
  54 static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END };
  55
  56 /* Insmod parameters */
  57 SENSORS_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 semaphore update_lock;
 100         char valid; /* zero until following fields are valid */
 101         unsigned long last_updated; /* in jiffies */
 102
 103         /* registers values */
 104         s16 temp1_input, temp1_crit, temp1_min, temp1_max, temp1_hyst;
 105 };
 106
 107
 108 /*
 109  * Sysfs attributes and callback functions
 110  */
 111
 112 static struct lm92_data *lm92_update_device(struct device *dev)
 113 {
 114         struct i2c_client *client = to_i2c_client(dev);
 115         struct lm92_data *data = i2c_get_clientdata(client);
 116
 117         down(&data->update_lock);
 118
 119         if (time_after(jiffies, data->last_updated + HZ)
 120          || !data->valid) {
 121                 dev_dbg(&client->dev, "Updating lm92 data\n");
 122                 data->temp1_input = swab16(i2c_smbus_read_word_data(client,
 123                                     LM92_REG_TEMP));
 124                 data->temp1_hyst = swab16(i2c_smbus_read_word_data(client,
 125                                     LM92_REG_TEMP_HYST));
 126                 data->temp1_crit = swab16(i2c_smbus_read_word_data(client,
 127                                     LM92_REG_TEMP_CRIT));
 128                 data->temp1_min = swab16(i2c_smbus_read_word_data(client,
 129                                     LM92_REG_TEMP_LOW));
 130                 data->temp1_max = swab16(i2c_smbus_read_word_data(client,
 131                                     LM92_REG_TEMP_HIGH));
 132
 133                 data->last_updated = jiffies;
 134                 data->valid = 1;
 135         }
 136
 137         up(&data->update_lock);
 138
 139         return data;
 140 }
 141
 142 #define show_temp(value) \
 143 static ssize_t show_##value(struct device *dev, char *buf) \
 144 { \
 145         struct lm92_data *data = lm92_update_device(dev); \
 146         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->value)); \
 147 }
 148 show_temp(temp1_input);
 149 show_temp(temp1_crit);
 150 show_temp(temp1_min);
 151 show_temp(temp1_max);
 152
 153 #define set_temp(value, reg) \
 154 static ssize_t set_##value(struct device *dev, const char *buf, \
 155         size_t count) \
 156 { \
 157         struct i2c_client *client = to_i2c_client(dev); \
 158         struct lm92_data *data = i2c_get_clientdata(client); \
 159         long val = simple_strtol(buf, NULL, 10); \
 160  \
 161         down(&data->update_lock); \
 162         data->value = TEMP_TO_REG(val); \
 163         i2c_smbus_write_word_data(client, reg, swab16(data->value)); \
 164         up(&data->update_lock); \
 165         return count; \
 166 }
 167 set_temp(temp1_crit, LM92_REG_TEMP_CRIT);
 168 set_temp(temp1_min, LM92_REG_TEMP_LOW);
 169 set_temp(temp1_max, LM92_REG_TEMP_HIGH);
 170
 171 static ssize_t show_temp1_crit_hyst(struct device *dev, char *buf)
 172 {
 173         struct lm92_data *data = lm92_update_device(dev);
 174         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_crit)
 175                        - TEMP_FROM_REG(data->temp1_hyst));
 176 }
 177 static ssize_t show_temp1_max_hyst(struct device *dev, char *buf)
 178 {
 179         struct lm92_data *data = lm92_update_device(dev);
 180         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_max)
 181                        - TEMP_FROM_REG(data->temp1_hyst));
 182 }
 183 static ssize_t show_temp1_min_hyst(struct device *dev, char *buf)
 184 {
 185         struct lm92_data *data = lm92_update_device(dev);
 186         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_min)
 187                        + TEMP_FROM_REG(data->temp1_hyst));
 188 }
 189
 190 static ssize_t set_temp1_crit_hyst(struct device *dev, const char *buf,
 191         size_t count)
 192 {
 193         struct i2c_client *client = to_i2c_client(dev);
 194         struct lm92_data *data = i2c_get_clientdata(client);
 195         long val = simple_strtol(buf, NULL, 10);
 196
 197         down(&data->update_lock);
 198         data->temp1_hyst = TEMP_FROM_REG(data->temp1_crit) - val;
 199         i2c_smbus_write_word_data(client, LM92_REG_TEMP_HYST,
 200                                   swab16(TEMP_TO_REG(data->temp1_hyst)));
 201         up(&data->update_lock);
 202         return count;
 203 }
 204
 205 static ssize_t show_alarms(struct device *dev, char *buf)
 206 {
 207         struct lm92_data *data = lm92_update_device(dev);
 208         return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp1_input));
 209 }
 210
 211 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL);
 212 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit,
 213         set_temp1_crit);
 214 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst,
 215         set_temp1_crit_hyst);
 216 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min,
 217         set_temp1_min);
 218 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL);
 219 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max,
 220         set_temp1_max);
 221 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL);
 222 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
 223
 224
 225 /*
 226  * Detection and registration
 227  */
 228
 229 static void lm92_init_client(struct i2c_client *client)
 230 {
 231         u8 config;
 232
 233         /* Start the conversions if needed */
 234         config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
 235         if (config & 0x01)
 236                 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
 237                                           config & 0xFE);
 238 }
 239
 240 /* The MAX6635 has no identification register, so we have to use tricks
 241    to identify it reliably. This is somewhat slow.
 242    Note that we do NOT rely on the 2 MSB of the configuration register
 243    always reading 0, as suggested by the datasheet, because it was once
 244    reported not to be true. */
 245 static int max6635_check(struct i2c_client *client)
 246 {
 247         u16 temp_low, temp_high, temp_hyst, temp_crit;
 248         u8 conf;
 249         int i;
 250
 251         /* No manufacturer ID register, so a read from this address will
 252            always return the last read value. */
 253         temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW);
 254         if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low)
 255                 return 0;
 256         temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH);
 257         if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high)
 258                 return 0;
 259
 260         /* Limits are stored as integer values (signed, 9-bit). */
 261         if ((temp_low & 0x7f00) || (temp_high & 0x7f00))
 262                 return 0;
 263         temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST);
 264         temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT);
 265         if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00))
 266                 return 0;
 267
 268         /* Registers addresses were found to cycle over 16-byte boundaries.
 269            We don't test all registers with all offsets so as to save some
 270            reads and time, but this should still be sufficient to dismiss
 271            non-MAX6635 chips. */
 272         conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
 273         for (i=16; i<96; i*=2) {
 274                 if (temp_hyst != i2c_smbus_read_word_data(client,
 275                                  LM92_REG_TEMP_HYST + i - 16)
 276                  || temp_crit != i2c_smbus_read_word_data(client,
 277                                  LM92_REG_TEMP_CRIT + i)
 278                  || temp_low != i2c_smbus_read_word_data(client,
 279                                 LM92_REG_TEMP_LOW + i + 16)
 280                  || temp_high != i2c_smbus_read_word_data(client,
 281                                  LM92_REG_TEMP_HIGH + i + 32)
 282                  || conf != i2c_smbus_read_byte_data(client,
 283                             LM92_REG_CONFIG + i))
 284                         return 0;
 285         }
 286
 287         return 1;
 288 }
 289
 290 /* The following function does more than just detection. If detection
 291    succeeds, it also registers the new chip. */
 292 static int lm92_detect(struct i2c_adapter *adapter, int address, int kind)
 293 {
 294         struct i2c_client *new_client;
 295         struct lm92_data *data;
 296         int err = 0;
 297         char *name;
 298
 299         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 300                                             | I2C_FUNC_SMBUS_WORD_DATA))
 301                 goto exit;
 302
 303         if (!(data = kmalloc(sizeof(struct lm92_data), GFP_KERNEL))) {
 304                 err = -ENOMEM;
 305                 goto exit;
 306         }
 307         memset(data, 0, sizeof(struct lm92_data));
 308
 309         /* Fill in enough client fields so that we can read from the chip,
 310            which is required for identication */
 311         new_client = &data->client;
 312         i2c_set_clientdata(new_client, data);
 313         new_client->addr = address;
 314         new_client->adapter = adapter;
 315         new_client->driver = &lm92_driver;
 316         new_client->flags = 0;
 317
 318         /* A negative kind means that the driver was loaded with no force
 319            parameter (default), so we must identify the chip. */
 320         if (kind < 0) {
 321                 u8 config = i2c_smbus_read_byte_data(new_client,
 322                              LM92_REG_CONFIG);
 323                 u16 man_id = i2c_smbus_read_word_data(new_client,
 324                              LM92_REG_MAN_ID);
 325
 326                 if ((config & 0xe0) == 0x00
 327                  && man_id == 0x0180) {
 328                         pr_info("lm92: Found National Semiconductor LM92 chip\n");
 329                         kind = lm92;
 330                 } else
 331                 if (max6635_check(new_client)) {
 332                         pr_info("lm92: Found Maxim MAX6635 chip\n");
 333                         kind = lm92; /* No separate prefix */
 334                 }
 335                 else
 336                         goto exit_free;
 337         } else
 338         if (kind == 0) /* Default to an LM92 if forced */
 339                 kind = lm92;
 340
 341         /* Give it the proper name */
 342         if (kind == lm92) {
 343                 name = "lm92";
 344         } else { /* Supposedly cannot happen */
 345                 dev_dbg(&new_client->dev, "Kind out of range?\n");
 346                 goto exit_free;
 347         }
 348
 349         /* Fill in the remaining client fields */
 350         strlcpy(new_client->name, name, I2C_NAME_SIZE);
 351         data->valid = 0;
 352         init_MUTEX(&data->update_lock);
 353
 354         /* Tell the i2c subsystem a new client has arrived */
 355         if ((err = i2c_attach_client(new_client)))
 356                 goto exit_free;
 357
 358         /* Initialize the chipset */
 359         lm92_init_client(new_client);
 360
 361         /* Register sysfs hooks */
 362         device_create_file(&new_client->dev, &dev_attr_temp1_input);
 363         device_create_file(&new_client->dev, &dev_attr_temp1_crit);
 364         device_create_file(&new_client->dev, &dev_attr_temp1_crit_hyst);
 365         device_create_file(&new_client->dev, &dev_attr_temp1_min);
 366         device_create_file(&new_client->dev, &dev_attr_temp1_min_hyst);
 367         device_create_file(&new_client->dev, &dev_attr_temp1_max);
 368         device_create_file(&new_client->dev, &dev_attr_temp1_max_hyst);
 369         device_create_file(&new_client->dev, &dev_attr_alarms);
 370
 371         return 0;
 372
 373 exit_free:
 374         kfree(data);
 375 exit:
 376         return err;
 377 }
 378
 379 static int lm92_attach_adapter(struct i2c_adapter *adapter)
 380 {
 381         if (!(adapter->class & I2C_CLASS_HWMON))
 382                 return 0;
 383         return i2c_detect(adapter, &addr_data, lm92_detect);
 384 }
 385
 386 static int lm92_detach_client(struct i2c_client *client)
 387 {
 388         int err;
 389
 390         if ((err = i2c_detach_client(client))) {
 391                 dev_err(&client->dev, "Client deregistration failed, "
 392                         "client not detached.\n");
 393                 return err;
 394         }
 395
 396         kfree(i2c_get_clientdata(client));
 397         return 0;
 398 }
 399
 400
 401 /*
 402  * Module and driver stuff
 403  */
 404
 405 static struct i2c_driver lm92_driver = {
 406         .owner          = THIS_MODULE,
 407         .name           = "lm92",
 408         .id             = I2C_DRIVERID_LM92,
 409         .flags          = I2C_DF_NOTIFY,
 410         .attach_adapter = lm92_attach_adapter,
 411         .detach_client  = lm92_detach_client,
 412 };
 413
 414 static int __init sensors_lm92_init(void)
 415 {
 416         return i2c_add_driver(&lm92_driver);
 417 }
 418
 419 static void __exit sensors_lm92_exit(void)
 420 {
 421         i2c_del_driver(&lm92_driver);
 422 }
 423
 424 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
 425 MODULE_DESCRIPTION("LM92/MAX6635 driver");
 426 MODULE_LICENSE("GPL");
 427
 428 module_init(sensors_lm92_init);
 429 module_exit(sensors_lm92_exit);