drivers/hwmon/lm77.c

   1 /*
   2     lm77.c - Part of lm_sensors, Linux kernel modules for hardware
   3              monitoring
   4
   5     Copyright (c) 2004  Andras BALI <drewie@freemail.hu>
   6
   7     Heavily based on lm75.c by Frodo Looijaard <frodol@dds.nl>.  The LM77
   8     is a temperature sensor and thermal window comparator with 0.5 deg
   9     resolution made by National Semiconductor.  Complete datasheet can be
  10     obtained at their site:
  11        http://www.national.com/pf/LM/LM77.html
  12
  13     This program is free software; you can redistribute it and/or modify
  14     it under the terms of the GNU General Public License as published by
  15     the Free Software Foundation; either version 2 of the License, or
  16     (at your option) any later version.
  17
  18     This program is distributed in the hope that it will be useful,
  19     but WITHOUT ANY WARRANTY; without even the implied warranty of
  20     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21     GNU General Public License for more details.
  22
  23     You should have received a copy of the GNU General Public License
  24     along with this program; if not, write to the Free Software
  25     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  26 */
  27
  28 #include <linux/module.h>
  29 #include <linux/init.h>
  30 #include <linux/slab.h>
  31 #include <linux/jiffies.h>
  32 #include <linux/i2c.h>
  33 #include <linux/hwmon.h>
  34 #include <linux/hwmon-sysfs.h>
  35 #include <linux/err.h>
  36 #include <linux/mutex.h>
  37
  38 /* Addresses to scan */
  39 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
  40                                                 I2C_CLIENT_END };
  41
  42 /* Insmod parameters */
  43 I2C_CLIENT_INSMOD_1(lm77);
  44
  45 /* The LM77 registers */
  46 #define LM77_REG_TEMP           0x00
  47 #define LM77_REG_CONF           0x01
  48 #define LM77_REG_TEMP_HYST      0x02
  49 #define LM77_REG_TEMP_CRIT      0x03
  50 #define LM77_REG_TEMP_MIN       0x04
  51 #define LM77_REG_TEMP_MAX       0x05
  52
  53 /* Each client has this additional data */
  54 struct lm77_data {
  55         struct device           *hwmon_dev;
  56         struct mutex            update_lock;
  57         char                    valid;
  58         unsigned long           last_updated;   /* In jiffies */
  59         int                     temp_input;     /* Temperatures */
  60         int                     temp_crit;
  61         int                     temp_min;
  62         int                     temp_max;
  63         int                     temp_hyst;
  64         u8                      alarms;
  65 };
  66
  67 static int lm77_probe(struct i2c_client *client,
  68                       const struct i2c_device_id *id);
  69 static int lm77_detect(struct i2c_client *client, int kind,
  70                        struct i2c_board_info *info);
  71 static void lm77_init_client(struct i2c_client *client);
  72 static int lm77_remove(struct i2c_client *client);
  73 static u16 lm77_read_value(struct i2c_client *client, u8 reg);
  74 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value);
  75
  76 static struct lm77_data *lm77_update_device(struct device *dev);
  77
  78
  79 static const struct i2c_device_id lm77_id[] = {
  80         { "lm77", lm77 },
  81         { }
  82 };
  83 MODULE_DEVICE_TABLE(i2c, lm77_id);
  84
  85 /* This is the driver that will be inserted */
  86 static struct i2c_driver lm77_driver = {
  87         .class          = I2C_CLASS_HWMON,
  88         .driver = {
  89                 .name   = "lm77",
  90         },
  91         .probe          = lm77_probe,
  92         .remove         = lm77_remove,
  93         .id_table       = lm77_id,
  94         .detect         = lm77_detect,
  95         .address_data   = &addr_data,
  96 };
  97
  98 /* straight from the datasheet */
  99 #define LM77_TEMP_MIN (-55000)
 100 #define LM77_TEMP_MAX 125000
 101
 102 /* In the temperature registers, the low 3 bits are not part of the
 103    temperature values; they are the status bits. */
 104 static inline s16 LM77_TEMP_TO_REG(int temp)
 105 {
 106         int ntemp = SENSORS_LIMIT(temp, LM77_TEMP_MIN, LM77_TEMP_MAX);
 107         return (ntemp / 500) * 8;
 108 }
 109
 110 static inline int LM77_TEMP_FROM_REG(s16 reg)
 111 {
 112         return (reg / 8) * 500;
 113 }
 114
 115 /* sysfs stuff */
 116
 117 /* read routines for temperature limits */
 118 #define show(value)     \
 119 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf)       \
 120 {                                                               \
 121         struct lm77_data *data = lm77_update_device(dev);       \
 122         return sprintf(buf, "%d\n", data->value);               \
 123 }
 124
 125 show(temp_input);
 126 show(temp_crit);
 127 show(temp_min);
 128 show(temp_max);
 129
 130 /* read routines for hysteresis values */
 131 static ssize_t show_temp_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf)
 132 {
 133         struct lm77_data *data = lm77_update_device(dev);
 134         return sprintf(buf, "%d\n", data->temp_crit - data->temp_hyst);
 135 }
 136 static ssize_t show_temp_min_hyst(struct device *dev, struct device_attribute *attr, char *buf)
 137 {
 138         struct lm77_data *data = lm77_update_device(dev);
 139         return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst);
 140 }
 141 static ssize_t show_temp_max_hyst(struct device *dev, struct device_attribute *attr, char *buf)
 142 {
 143         struct lm77_data *data = lm77_update_device(dev);
 144         return sprintf(buf, "%d\n", data->temp_max - data->temp_hyst);
 145 }
 146
 147 /* write routines */
 148 #define set(value, reg) \
 149 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)    \
 150 {                                                                               \
 151         struct i2c_client *client = to_i2c_client(dev);                         \
 152         struct lm77_data *data = i2c_get_clientdata(client);                    \
 153         long val = simple_strtol(buf, NULL, 10);                                \
 154                                                                                 \
 155         mutex_lock(&data->update_lock);                                         \
 156         data->value = val;                              \
 157         lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value));           \
 158         mutex_unlock(&data->update_lock);                                       \
 159         return count;                                                           \
 160 }
 161
 162 set(temp_min, LM77_REG_TEMP_MIN);
 163 set(temp_max, LM77_REG_TEMP_MAX);
 164
 165 /* hysteresis is stored as a relative value on the chip, so it has to be
 166    converted first */
 167 static ssize_t set_temp_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 168 {
 169         struct i2c_client *client = to_i2c_client(dev);
 170         struct lm77_data *data = i2c_get_clientdata(client);
 171         unsigned long val = simple_strtoul(buf, NULL, 10);
 172
 173         mutex_lock(&data->update_lock);
 174         data->temp_hyst = data->temp_crit - val;
 175         lm77_write_value(client, LM77_REG_TEMP_HYST,
 176                          LM77_TEMP_TO_REG(data->temp_hyst));
 177         mutex_unlock(&data->update_lock);
 178         return count;
 179 }
 180
 181 /* preserve hysteresis when setting T_crit */
 182 static ssize_t set_temp_crit(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 183 {
 184         struct i2c_client *client = to_i2c_client(dev);
 185         struct lm77_data *data = i2c_get_clientdata(client);
 186         long val = simple_strtoul(buf, NULL, 10);
 187         int oldcrithyst;
 188
 189         mutex_lock(&data->update_lock);
 190         oldcrithyst = data->temp_crit - data->temp_hyst;
 191         data->temp_crit = val;
 192         data->temp_hyst = data->temp_crit - oldcrithyst;
 193         lm77_write_value(client, LM77_REG_TEMP_CRIT,
 194                          LM77_TEMP_TO_REG(data->temp_crit));
 195         lm77_write_value(client, LM77_REG_TEMP_HYST,
 196                          LM77_TEMP_TO_REG(data->temp_hyst));
 197         mutex_unlock(&data->update_lock);
 198         return count;
 199 }
 200
 201 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
 202                           char *buf)
 203 {
 204         int bitnr = to_sensor_dev_attr(attr)->index;
 205         struct lm77_data *data = lm77_update_device(dev);
 206         return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1);
 207 }
 208
 209 static DEVICE_ATTR(temp1_input, S_IRUGO,
 210                    show_temp_input, NULL);
 211 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO,
 212                    show_temp_crit, set_temp_crit);
 213 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
 214                    show_temp_min, set_temp_min);
 215 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 216                    show_temp_max, set_temp_max);
 217
 218 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO,
 219                    show_temp_crit_hyst, set_temp_crit_hyst);
 220 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO,
 221                    show_temp_min_hyst, NULL);
 222 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO,
 223                    show_temp_max_hyst, NULL);
 224
 225 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
 226 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
 227 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);
 228
 229 static struct attribute *lm77_attributes[] = {
 230         &dev_attr_temp1_input.attr,
 231         &dev_attr_temp1_crit.attr,
 232         &dev_attr_temp1_min.attr,
 233         &dev_attr_temp1_max.attr,
 234         &dev_attr_temp1_crit_hyst.attr,
 235         &dev_attr_temp1_min_hyst.attr,
 236         &dev_attr_temp1_max_hyst.attr,
 237         &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
 238         &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 239         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 240         NULL
 241 };
 242
 243 static const struct attribute_group lm77_group = {
 244         .attrs = lm77_attributes,
 245 };
 246
 247 /* Return 0 if detection is successful, -ENODEV otherwise */
 248 static int lm77_detect(struct i2c_client *new_client, int kind,
 249                        struct i2c_board_info *info)
 250 {
 251         struct i2c_adapter *adapter = new_client->adapter;
 252         int i, cur, conf, hyst, crit, min, max;
 253
 254         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 255                                      I2C_FUNC_SMBUS_WORD_DATA))
 256                 return -ENODEV;
 257
 258         /* Here comes the remaining detection.  Since the LM77 has no
 259            register dedicated to identification, we have to rely on the
 260            following tricks:
 261
 262            1. the high 4 bits represent the sign and thus they should
 263               always be the same
 264            2. the high 3 bits are unused in the configuration register
 265            3. addresses 0x06 and 0x07 return the last read value
 266            4. registers cycling over 8-address boundaries
 267
 268            Word-sized registers are high-byte first. */
 269
 270         /* addresses cycling */
 271         cur = i2c_smbus_read_word_data(new_client, 0);
 272         conf = i2c_smbus_read_byte_data(new_client, 1);
 273         hyst = i2c_smbus_read_word_data(new_client, 2);
 274         crit = i2c_smbus_read_word_data(new_client, 3);
 275         min = i2c_smbus_read_word_data(new_client, 4);
 276         max = i2c_smbus_read_word_data(new_client, 5);
 277         for (i = 8; i <= 0xff; i += 8) {
 278                 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
 279                  || i2c_smbus_read_word_data(new_client, i + 2) != hyst
 280                  || i2c_smbus_read_word_data(new_client, i + 3) != crit
 281                  || i2c_smbus_read_word_data(new_client, i + 4) != min
 282                  || i2c_smbus_read_word_data(new_client, i + 5) != max)
 283                         return -ENODEV;
 284         }
 285
 286         /* sign bits */
 287         if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0)
 288          || ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0)
 289          || ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0)
 290          || ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0)
 291          || ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0))
 292                 return -ENODEV;
 293
 294         /* unused bits */
 295         if (conf & 0xe0)
 296                 return -ENODEV;
 297
 298         /* 0x06 and 0x07 return the last read value */
 299         cur = i2c_smbus_read_word_data(new_client, 0);
 300         if (i2c_smbus_read_word_data(new_client, 6) != cur
 301          || i2c_smbus_read_word_data(new_client, 7) != cur)
 302                 return -ENODEV;
 303         hyst = i2c_smbus_read_word_data(new_client, 2);
 304         if (i2c_smbus_read_word_data(new_client, 6) != hyst
 305          || i2c_smbus_read_word_data(new_client, 7) != hyst)
 306                 return -ENODEV;
 307         min = i2c_smbus_read_word_data(new_client, 4);
 308         if (i2c_smbus_read_word_data(new_client, 6) != min
 309          || i2c_smbus_read_word_data(new_client, 7) != min)
 310                 return -ENODEV;
 311
 312         strlcpy(info->type, "lm77", I2C_NAME_SIZE);
 313
 314         return 0;
 315 }
 316
 317 static int lm77_probe(struct i2c_client *new_client,
 318                       const struct i2c_device_id *id)
 319 {
 320         struct lm77_data *data;
 321         int err;
 322
 323         data = kzalloc(sizeof(struct lm77_data), GFP_KERNEL);
 324         if (!data) {
 325                 err = -ENOMEM;
 326                 goto exit;
 327         }
 328
 329         i2c_set_clientdata(new_client, data);
 330         data->valid = 0;
 331         mutex_init(&data->update_lock);
 332
 333         /* Initialize the LM77 chip */
 334         lm77_init_client(new_client);
 335
 336         /* Register sysfs hooks */
 337         if ((err = sysfs_create_group(&new_client->dev.kobj, &lm77_group)))
 338                 goto exit_free;
 339
 340         data->hwmon_dev = hwmon_device_register(&new_client->dev);
 341         if (IS_ERR(data->hwmon_dev)) {
 342                 err = PTR_ERR(data->hwmon_dev);
 343                 goto exit_remove;
 344         }
 345
 346         return 0;
 347
 348 exit_remove:
 349         sysfs_remove_group(&new_client->dev.kobj, &lm77_group);
 350 exit_free:
 351         kfree(data);
 352 exit:
 353         return err;
 354 }
 355
 356 static int lm77_remove(struct i2c_client *client)
 357 {
 358         struct lm77_data *data = i2c_get_clientdata(client);
 359         hwmon_device_unregister(data->hwmon_dev);
 360         sysfs_remove_group(&client->dev.kobj, &lm77_group);
 361         kfree(data);
 362         return 0;
 363 }
 364
 365 /* All registers are word-sized, except for the configuration register.
 366    The LM77 uses the high-byte first convention. */
 367 static u16 lm77_read_value(struct i2c_client *client, u8 reg)
 368 {
 369         if (reg == LM77_REG_CONF)
 370                 return i2c_smbus_read_byte_data(client, reg);
 371         else
 372                 return swab16(i2c_smbus_read_word_data(client, reg));
 373 }
 374
 375 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value)
 376 {
 377         if (reg == LM77_REG_CONF)
 378                 return i2c_smbus_write_byte_data(client, reg, value);
 379         else
 380                 return i2c_smbus_write_word_data(client, reg, swab16(value));
 381 }
 382
 383 static void lm77_init_client(struct i2c_client *client)
 384 {
 385         /* Initialize the LM77 chip - turn off shutdown mode */
 386         int conf = lm77_read_value(client, LM77_REG_CONF);
 387         if (conf & 1)
 388                 lm77_write_value(client, LM77_REG_CONF, conf & 0xfe);
 389 }
 390
 391 static struct lm77_data *lm77_update_device(struct device *dev)
 392 {
 393         struct i2c_client *client = to_i2c_client(dev);
 394         struct lm77_data *data = i2c_get_clientdata(client);
 395
 396         mutex_lock(&data->update_lock);
 397
 398         if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
 399             || !data->valid) {
 400                 dev_dbg(&client->dev, "Starting lm77 update\n");
 401                 data->temp_input =
 402                         LM77_TEMP_FROM_REG(lm77_read_value(client,
 403                                                            LM77_REG_TEMP));
 404                 data->temp_hyst =
 405                         LM77_TEMP_FROM_REG(lm77_read_value(client,
 406                                                            LM77_REG_TEMP_HYST));
 407                 data->temp_crit =
 408                         LM77_TEMP_FROM_REG(lm77_read_value(client,
 409                                                            LM77_REG_TEMP_CRIT));
 410                 data->temp_min =
 411                         LM77_TEMP_FROM_REG(lm77_read_value(client,
 412                                                            LM77_REG_TEMP_MIN));
 413                 data->temp_max =
 414                         LM77_TEMP_FROM_REG(lm77_read_value(client,
 415                                                            LM77_REG_TEMP_MAX));
 416                 data->alarms =
 417                         lm77_read_value(client, LM77_REG_TEMP) & 0x0007;
 418                 data->last_updated = jiffies;
 419                 data->valid = 1;
 420         }
 421
 422         mutex_unlock(&data->update_lock);
 423
 424         return data;
 425 }
 426
 427 static int __init sensors_lm77_init(void)
 428 {
 429         return i2c_add_driver(&lm77_driver);
 430 }
 431
 432 static void __exit sensors_lm77_exit(void)
 433 {
 434         i2c_del_driver(&lm77_driver);
 435 }
 436
 437 MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>");
 438 MODULE_DESCRIPTION("LM77 driver");
 439 MODULE_LICENSE("GPL");
 440
 441 module_init(sensors_lm77_init);
 442 module_exit(sensors_lm77_exit);