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 #include <linux/jiffies.h>
  52
  53 /*
  54  * The LM92 and MAX6635 have 2 two-state pins for address selection,
  55  * resulting in 4 possible addresses.
  56  */
  57 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
  58                                                 I2C_CLIENT_END };
  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 /*
  70  * The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
  71  * left-justified in 16-bit registers. No rounding is done, with such
  72  * a resolution it's just not worth it. Note that the MAX6635 doesn't
  73  * make use of the 4 lower bits for limits (i.e. effective resolution
  74  * for limits is 1 degree Celsius).
  75  */
  76 static inline int TEMP_FROM_REG(s16 reg)
  77 {
  78         return reg / 8 * 625 / 10;
  79 }
  80
  81 static inline s16 TEMP_TO_REG(int val)
  82 {
  83         if (val <= -60000)
  84                 return -60000 * 10 / 625 * 8;
  85         if (val >= 160000)
  86                 return 160000 * 10 / 625 * 8;
  87         return val * 10 / 625 * 8;
  88 }
  89
  90 /* Alarm flags are stored in the 3 LSB of the temperature register */
  91 static inline u8 ALARMS_FROM_REG(s16 reg)
  92 {
  93         return reg & 0x0007;
  94 }
  95
  96 /* Driver data (common to all clients) */
  97 static struct i2c_driver lm92_driver;
  98
  99 /* Client data (each client gets its own) */
 100 struct lm92_data {
 101         struct device *hwmon_dev;
 102         struct mutex update_lock;
 103         char valid; /* zero until following fields are valid */
 104         unsigned long last_updated; /* in jiffies */
 105
 106         /* registers values */
 107         s16 temp1_input, temp1_crit, temp1_min, temp1_max, temp1_hyst;
 108 };
 109
 110
 111 /*
 112  * Sysfs attributes and callback functions
 113  */
 114
 115 static struct lm92_data *lm92_update_device(struct device *dev)
 116 {
 117         struct i2c_client *client = to_i2c_client(dev);
 118         struct lm92_data *data = i2c_get_clientdata(client);
 119
 120         mutex_lock(&data->update_lock);
 121
 122         if (time_after(jiffies, data->last_updated + HZ)
 123          || !data->valid) {
 124                 dev_dbg(&client->dev, "Updating lm92 data\n");
 125                 data->temp1_input = i2c_smbus_read_word_swapped(client,
 126                                     LM92_REG_TEMP);
 127                 data->temp1_hyst = i2c_smbus_read_word_swapped(client,
 128                                     LM92_REG_TEMP_HYST);
 129                 data->temp1_crit = i2c_smbus_read_word_swapped(client,
 130                                     LM92_REG_TEMP_CRIT);
 131                 data->temp1_min = i2c_smbus_read_word_swapped(client,
 132                                     LM92_REG_TEMP_LOW);
 133                 data->temp1_max = i2c_smbus_read_word_swapped(client,
 134                                     LM92_REG_TEMP_HIGH);
 135
 136                 data->last_updated = jiffies;
 137                 data->valid = 1;
 138         }
 139
 140         mutex_unlock(&data->update_lock);
 141
 142         return data;
 143 }
 144
 145 #define show_temp(value) \
 146 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, \
 147                             char *buf) \
 148 { \
 149         struct lm92_data *data = lm92_update_device(dev); \
 150         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->value)); \
 151 }
 152 show_temp(temp1_input);
 153 show_temp(temp1_crit);
 154 show_temp(temp1_min);
 155 show_temp(temp1_max);
 156
 157 #define set_temp(value, reg) \
 158 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, \
 159                            const char *buf, \
 160         size_t count) \
 161 { \
 162         struct i2c_client *client = to_i2c_client(dev); \
 163         struct lm92_data *data = i2c_get_clientdata(client); \
 164         long val; \
 165         int err = kstrtol(buf, 10, &val); \
 166         if (err) \
 167                 return err; \
 168 \
 169         mutex_lock(&data->update_lock); \
 170         data->value = TEMP_TO_REG(val); \
 171         i2c_smbus_write_word_swapped(client, reg, data->value); \
 172         mutex_unlock(&data->update_lock); \
 173         return count; \
 174 }
 175 set_temp(temp1_crit, LM92_REG_TEMP_CRIT);
 176 set_temp(temp1_min, LM92_REG_TEMP_LOW);
 177 set_temp(temp1_max, LM92_REG_TEMP_HIGH);
 178
 179 static ssize_t show_temp1_crit_hyst(struct device *dev,
 180                                     struct device_attribute *attr, char *buf)
 181 {
 182         struct lm92_data *data = lm92_update_device(dev);
 183         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_crit)
 184                        - TEMP_FROM_REG(data->temp1_hyst));
 185 }
 186 static ssize_t show_temp1_max_hyst(struct device *dev,
 187                                    struct device_attribute *attr, char *buf)
 188 {
 189         struct lm92_data *data = lm92_update_device(dev);
 190         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_max)
 191                        - TEMP_FROM_REG(data->temp1_hyst));
 192 }
 193 static ssize_t show_temp1_min_hyst(struct device *dev,
 194                                    struct device_attribute *attr, char *buf)
 195 {
 196         struct lm92_data *data = lm92_update_device(dev);
 197         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_min)
 198                        + TEMP_FROM_REG(data->temp1_hyst));
 199 }
 200
 201 static ssize_t set_temp1_crit_hyst(struct device *dev,
 202                                    struct device_attribute *attr,
 203                                    const char *buf, size_t count)
 204 {
 205         struct i2c_client *client = to_i2c_client(dev);
 206         struct lm92_data *data = i2c_get_clientdata(client);
 207         long val;
 208         int err;
 209
 210         err = kstrtol(buf, 10, &val);
 211         if (err)
 212                 return err;
 213
 214         mutex_lock(&data->update_lock);
 215         data->temp1_hyst = TEMP_FROM_REG(data->temp1_crit) - val;
 216         i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST,
 217                                      TEMP_TO_REG(data->temp1_hyst));
 218         mutex_unlock(&data->update_lock);
 219         return count;
 220 }
 221
 222 static ssize_t show_alarms(struct device *dev, struct device_attribute *attr,
 223                            char *buf)
 224 {
 225         struct lm92_data *data = lm92_update_device(dev);
 226         return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp1_input));
 227 }
 228
 229 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
 230                           char *buf)
 231 {
 232         int bitnr = to_sensor_dev_attr(attr)->index;
 233         struct lm92_data *data = lm92_update_device(dev);
 234         return sprintf(buf, "%d\n", (data->temp1_input >> bitnr) & 1);
 235 }
 236
 237 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL);
 238 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit,
 239         set_temp1_crit);
 240 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst,
 241         set_temp1_crit_hyst);
 242 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min,
 243         set_temp1_min);
 244 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL);
 245 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max,
 246         set_temp1_max);
 247 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL);
 248 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
 249 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
 250 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
 251 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);
 252
 253
 254 /*
 255  * Detection and registration
 256  */
 257
 258 static void lm92_init_client(struct i2c_client *client)
 259 {
 260         u8 config;
 261
 262         /* Start the conversions if needed */
 263         config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
 264         if (config & 0x01)
 265                 i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
 266                                           config & 0xFE);
 267 }
 268
 269 /*
 270  * The MAX6635 has no identification register, so we have to use tricks
 271  * to identify it reliably. This is somewhat slow.
 272  * Note that we do NOT rely on the 2 MSB of the configuration register
 273  * always reading 0, as suggested by the datasheet, because it was once
 274  * reported not to be true.
 275  */
 276 static int max6635_check(struct i2c_client *client)
 277 {
 278         u16 temp_low, temp_high, temp_hyst, temp_crit;
 279         u8 conf;
 280         int i;
 281
 282         /*
 283          * No manufacturer ID register, so a read from this address will
 284          * always return the last read value.
 285          */
 286         temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW);
 287         if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low)
 288                 return 0;
 289         temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH);
 290         if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high)
 291                 return 0;
 292
 293         /* Limits are stored as integer values (signed, 9-bit). */
 294         if ((temp_low & 0x7f00) || (temp_high & 0x7f00))
 295                 return 0;
 296         temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST);
 297         temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT);
 298         if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00))
 299                 return 0;
 300
 301         /*
 302          * Registers addresses were found to cycle over 16-byte boundaries.
 303          * We don't test all registers with all offsets so as to save some
 304          * reads and time, but this should still be sufficient to dismiss
 305          * non-MAX6635 chips.
 306          */
 307         conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
 308         for (i = 16; i < 96; i *= 2) {
 309                 if (temp_hyst != i2c_smbus_read_word_data(client,
 310                                  LM92_REG_TEMP_HYST + i - 16)
 311                  || temp_crit != i2c_smbus_read_word_data(client,
 312                                  LM92_REG_TEMP_CRIT + i)
 313                  || temp_low != i2c_smbus_read_word_data(client,
 314                                 LM92_REG_TEMP_LOW + i + 16)
 315                  || temp_high != i2c_smbus_read_word_data(client,
 316                                  LM92_REG_TEMP_HIGH + i + 32)
 317                  || conf != i2c_smbus_read_byte_data(client,
 318                             LM92_REG_CONFIG + i))
 319                         return 0;
 320         }
 321
 322         return 1;
 323 }
 324
 325 static struct attribute *lm92_attributes[] = {
 326         &dev_attr_temp1_input.attr,
 327         &dev_attr_temp1_crit.attr,
 328         &dev_attr_temp1_crit_hyst.attr,
 329         &dev_attr_temp1_min.attr,
 330         &dev_attr_temp1_min_hyst.attr,
 331         &dev_attr_temp1_max.attr,
 332         &dev_attr_temp1_max_hyst.attr,
 333         &dev_attr_alarms.attr,
 334         &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
 335         &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 336         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 337         NULL
 338 };
 339
 340 static const struct attribute_group lm92_group = {
 341         .attrs = lm92_attributes,
 342 };
 343
 344 /* Return 0 if detection is successful, -ENODEV otherwise */
 345 static int lm92_detect(struct i2c_client *new_client,
 346                        struct i2c_board_info *info)
 347 {
 348         struct i2c_adapter *adapter = new_client->adapter;
 349         u8 config;
 350         u16 man_id;
 351
 352         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 353                                             | I2C_FUNC_SMBUS_WORD_DATA))
 354                 return -ENODEV;
 355
 356         config = i2c_smbus_read_byte_data(new_client, LM92_REG_CONFIG);
 357         man_id = i2c_smbus_read_word_data(new_client, LM92_REG_MAN_ID);
 358
 359         if ((config & 0xe0) == 0x00 && man_id == 0x0180)
 360                 pr_info("lm92: Found National Semiconductor LM92 chip\n");
 361         else if (max6635_check(new_client))
 362                 pr_info("lm92: Found Maxim MAX6635 chip\n");
 363         else
 364                 return -ENODEV;
 365
 366         strlcpy(info->type, "lm92", I2C_NAME_SIZE);
 367
 368         return 0;
 369 }
 370
 371 static int lm92_probe(struct i2c_client *new_client,
 372                       const struct i2c_device_id *id)
 373 {
 374         struct lm92_data *data;
 375         int err;
 376
 377         data = devm_kzalloc(&new_client->dev, sizeof(struct lm92_data),
 378                             GFP_KERNEL);
 379         if (!data)
 380                 return -ENOMEM;
 381
 382         i2c_set_clientdata(new_client, data);
 383         data->valid = 0;
 384         mutex_init(&data->update_lock);
 385
 386         /* Initialize the chipset */
 387         lm92_init_client(new_client);
 388
 389         /* Register sysfs hooks */
 390         err = sysfs_create_group(&new_client->dev.kobj, &lm92_group);
 391         if (err)
 392                 return err;
 393
 394         data->hwmon_dev = hwmon_device_register(&new_client->dev);
 395         if (IS_ERR(data->hwmon_dev)) {
 396                 err = PTR_ERR(data->hwmon_dev);
 397                 goto exit_remove;
 398         }
 399
 400         return 0;
 401
 402 exit_remove:
 403         sysfs_remove_group(&new_client->dev.kobj, &lm92_group);
 404         return err;
 405 }
 406
 407 static int lm92_remove(struct i2c_client *client)
 408 {
 409         struct lm92_data *data = i2c_get_clientdata(client);
 410
 411         hwmon_device_unregister(data->hwmon_dev);
 412         sysfs_remove_group(&client->dev.kobj, &lm92_group);
 413
 414         return 0;
 415 }
 416
 417
 418 /*
 419  * Module and driver stuff
 420  */
 421
 422 static const struct i2c_device_id lm92_id[] = {
 423         { "lm92", 0 },
 424         /* max6635 could be added here */
 425         { }
 426 };
 427 MODULE_DEVICE_TABLE(i2c, lm92_id);
 428
 429 static struct i2c_driver lm92_driver = {
 430         .class          = I2C_CLASS_HWMON,
 431         .driver = {
 432                 .name   = "lm92",
 433         },
 434         .probe          = lm92_probe,
 435         .remove         = lm92_remove,
 436         .id_table       = lm92_id,
 437         .detect         = lm92_detect,
 438         .address_list   = normal_i2c,
 439 };
 440
 441 module_i2c_driver(lm92_driver);
 442
 443 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
 444 MODULE_DESCRIPTION("LM92/MAX6635 driver");
 445 MODULE_LICENSE("GPL");