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 /* The LM77 registers */
  43 #define LM77_REG_TEMP           0x00
  44 #define LM77_REG_CONF           0x01
  45 #define LM77_REG_TEMP_HYST      0x02
  46 #define LM77_REG_TEMP_CRIT      0x03
  47 #define LM77_REG_TEMP_MIN       0x04
  48 #define LM77_REG_TEMP_MAX       0x05
  49
  50 /* Each client has this additional data */
  51 struct lm77_data {
  52         struct device           *hwmon_dev;
  53         struct mutex            update_lock;
  54         char                    valid;
  55         unsigned long           last_updated;   /* In jiffies */
  56         int                     temp_input;     /* Temperatures */
  57         int                     temp_crit;
  58         int                     temp_min;
  59         int                     temp_max;
  60         int                     temp_hyst;
  61         u8                      alarms;
  62 };
  63
  64 static int lm77_probe(struct i2c_client *client,
  65                       const struct i2c_device_id *id);
  66 static int lm77_detect(struct i2c_client *client, struct i2c_board_info *info);
  67 static void lm77_init_client(struct i2c_client *client);
  68 static int lm77_remove(struct i2c_client *client);
  69 static u16 lm77_read_value(struct i2c_client *client, u8 reg);
  70 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value);
  71
  72 static struct lm77_data *lm77_update_device(struct device *dev);
  73
  74
  75 static const struct i2c_device_id lm77_id[] = {
  76         { "lm77", 0 },
  77         { }
  78 };
  79 MODULE_DEVICE_TABLE(i2c, lm77_id);
  80
  81 /* This is the driver that will be inserted */
  82 static struct i2c_driver lm77_driver = {
  83         .class          = I2C_CLASS_HWMON,
  84         .driver = {
  85                 .name   = "lm77",
  86         },
  87         .probe          = lm77_probe,
  88         .remove         = lm77_remove,
  89         .id_table       = lm77_id,
  90         .detect         = lm77_detect,
  91         .address_list   = normal_i2c,
  92 };
  93
  94 /* straight from the datasheet */
  95 #define LM77_TEMP_MIN (-55000)
  96 #define LM77_TEMP_MAX 125000
  97
  98 /* In the temperature registers, the low 3 bits are not part of the
  99    temperature values; they are the status bits. */
 100 static inline s16 LM77_TEMP_TO_REG(int temp)
 101 {
 102         int ntemp = SENSORS_LIMIT(temp, LM77_TEMP_MIN, LM77_TEMP_MAX);
 103         return (ntemp / 500) * 8;
 104 }
 105
 106 static inline int LM77_TEMP_FROM_REG(s16 reg)
 107 {
 108         return (reg / 8) * 500;
 109 }
 110
 111 /* sysfs stuff */
 112
 113 /* read routines for temperature limits */
 114 #define show(value)     \
 115 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf)       \
 116 {                                                               \
 117         struct lm77_data *data = lm77_update_device(dev);       \
 118         return sprintf(buf, "%d\n", data->value);               \
 119 }
 120
 121 show(temp_input);
 122 show(temp_crit);
 123 show(temp_min);
 124 show(temp_max);
 125
 126 /* read routines for hysteresis values */
 127 static ssize_t show_temp_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf)
 128 {
 129         struct lm77_data *data = lm77_update_device(dev);
 130         return sprintf(buf, "%d\n", data->temp_crit - data->temp_hyst);
 131 }
 132 static ssize_t show_temp_min_hyst(struct device *dev, struct device_attribute *attr, char *buf)
 133 {
 134         struct lm77_data *data = lm77_update_device(dev);
 135         return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst);
 136 }
 137 static ssize_t show_temp_max_hyst(struct device *dev, struct device_attribute *attr, char *buf)
 138 {
 139         struct lm77_data *data = lm77_update_device(dev);
 140         return sprintf(buf, "%d\n", data->temp_max - data->temp_hyst);
 141 }
 142
 143 /* write routines */
 144 #define set(value, reg) \
 145 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)    \
 146 {                                                                               \
 147         struct i2c_client *client = to_i2c_client(dev);                         \
 148         struct lm77_data *data = i2c_get_clientdata(client);                    \
 149         long val = simple_strtol(buf, NULL, 10);                                \
 150                                                                                 \
 151         mutex_lock(&data->update_lock);                                         \
 152         data->value = val;                              \
 153         lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value));           \
 154         mutex_unlock(&data->update_lock);                                       \
 155         return count;                                                           \
 156 }
 157
 158 set(temp_min, LM77_REG_TEMP_MIN);
 159 set(temp_max, LM77_REG_TEMP_MAX);
 160
 161 /* hysteresis is stored as a relative value on the chip, so it has to be
 162    converted first */
 163 static ssize_t set_temp_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 164 {
 165         struct i2c_client *client = to_i2c_client(dev);
 166         struct lm77_data *data = i2c_get_clientdata(client);
 167         unsigned long val = simple_strtoul(buf, NULL, 10);
 168
 169         mutex_lock(&data->update_lock);
 170         data->temp_hyst = data->temp_crit - val;
 171         lm77_write_value(client, LM77_REG_TEMP_HYST,
 172                          LM77_TEMP_TO_REG(data->temp_hyst));
 173         mutex_unlock(&data->update_lock);
 174         return count;
 175 }
 176
 177 /* preserve hysteresis when setting T_crit */
 178 static ssize_t set_temp_crit(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 179 {
 180         struct i2c_client *client = to_i2c_client(dev);
 181         struct lm77_data *data = i2c_get_clientdata(client);
 182         long val = simple_strtoul(buf, NULL, 10);
 183         int oldcrithyst;
 184
 185         mutex_lock(&data->update_lock);
 186         oldcrithyst = data->temp_crit - data->temp_hyst;
 187         data->temp_crit = val;
 188         data->temp_hyst = data->temp_crit - oldcrithyst;
 189         lm77_write_value(client, LM77_REG_TEMP_CRIT,
 190                          LM77_TEMP_TO_REG(data->temp_crit));
 191         lm77_write_value(client, LM77_REG_TEMP_HYST,
 192                          LM77_TEMP_TO_REG(data->temp_hyst));
 193         mutex_unlock(&data->update_lock);
 194         return count;
 195 }
 196
 197 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
 198                           char *buf)
 199 {
 200         int bitnr = to_sensor_dev_attr(attr)->index;
 201         struct lm77_data *data = lm77_update_device(dev);
 202         return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1);
 203 }
 204
 205 static DEVICE_ATTR(temp1_input, S_IRUGO,
 206                    show_temp_input, NULL);
 207 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO,
 208                    show_temp_crit, set_temp_crit);
 209 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
 210                    show_temp_min, set_temp_min);
 211 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 212                    show_temp_max, set_temp_max);
 213
 214 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO,
 215                    show_temp_crit_hyst, set_temp_crit_hyst);
 216 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO,
 217                    show_temp_min_hyst, NULL);
 218 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO,
 219                    show_temp_max_hyst, NULL);
 220
 221 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
 222 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
 223 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);
 224
 225 static struct attribute *lm77_attributes[] = {
 226         &dev_attr_temp1_input.attr,
 227         &dev_attr_temp1_crit.attr,
 228         &dev_attr_temp1_min.attr,
 229         &dev_attr_temp1_max.attr,
 230         &dev_attr_temp1_crit_hyst.attr,
 231         &dev_attr_temp1_min_hyst.attr,
 232         &dev_attr_temp1_max_hyst.attr,
 233         &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
 234         &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 235         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 236         NULL
 237 };
 238
 239 static const struct attribute_group lm77_group = {
 240         .attrs = lm77_attributes,
 241 };
 242
 243 /* Return 0 if detection is successful, -ENODEV otherwise */
 244 static int lm77_detect(struct i2c_client *new_client,
 245                        struct i2c_board_info *info)
 246 {
 247         struct i2c_adapter *adapter = new_client->adapter;
 248         int i, cur, conf, hyst, crit, min, max;
 249
 250         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 251                                      I2C_FUNC_SMBUS_WORD_DATA))
 252                 return -ENODEV;
 253
 254         /* Here comes the remaining detection.  Since the LM77 has no
 255            register dedicated to identification, we have to rely on the
 256            following tricks:
 257
 258            1. the high 4 bits represent the sign and thus they should
 259               always be the same
 260            2. the high 3 bits are unused in the configuration register
 261            3. addresses 0x06 and 0x07 return the last read value
 262            4. registers cycling over 8-address boundaries
 263
 264            Word-sized registers are high-byte first. */
 265
 266         /* addresses cycling */
 267         cur = i2c_smbus_read_word_data(new_client, 0);
 268         conf = i2c_smbus_read_byte_data(new_client, 1);
 269         hyst = i2c_smbus_read_word_data(new_client, 2);
 270         crit = i2c_smbus_read_word_data(new_client, 3);
 271         min = i2c_smbus_read_word_data(new_client, 4);
 272         max = i2c_smbus_read_word_data(new_client, 5);
 273         for (i = 8; i <= 0xff; i += 8) {
 274                 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
 275                  || i2c_smbus_read_word_data(new_client, i + 2) != hyst
 276                  || i2c_smbus_read_word_data(new_client, i + 3) != crit
 277                  || i2c_smbus_read_word_data(new_client, i + 4) != min
 278                  || i2c_smbus_read_word_data(new_client, i + 5) != max)
 279                         return -ENODEV;
 280         }
 281
 282         /* sign bits */
 283         if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0)
 284          || ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0)
 285          || ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0)
 286          || ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0)
 287          || ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0))
 288                 return -ENODEV;
 289
 290         /* unused bits */
 291         if (conf & 0xe0)
 292                 return -ENODEV;
 293
 294         /* 0x06 and 0x07 return the last read value */
 295         cur = i2c_smbus_read_word_data(new_client, 0);
 296         if (i2c_smbus_read_word_data(new_client, 6) != cur
 297          || i2c_smbus_read_word_data(new_client, 7) != cur)
 298                 return -ENODEV;
 299         hyst = i2c_smbus_read_word_data(new_client, 2);
 300         if (i2c_smbus_read_word_data(new_client, 6) != hyst
 301          || i2c_smbus_read_word_data(new_client, 7) != hyst)
 302                 return -ENODEV;
 303         min = i2c_smbus_read_word_data(new_client, 4);
 304         if (i2c_smbus_read_word_data(new_client, 6) != min
 305          || i2c_smbus_read_word_data(new_client, 7) != min)
 306                 return -ENODEV;
 307
 308         strlcpy(info->type, "lm77", I2C_NAME_SIZE);
 309
 310         return 0;
 311 }
 312
 313 static int lm77_probe(struct i2c_client *new_client,
 314                       const struct i2c_device_id *id)
 315 {
 316         struct lm77_data *data;
 317         int err;
 318
 319         data = kzalloc(sizeof(struct lm77_data), GFP_KERNEL);
 320         if (!data) {
 321                 err = -ENOMEM;
 322                 goto exit;
 323         }
 324
 325         i2c_set_clientdata(new_client, data);
 326         data->valid = 0;
 327         mutex_init(&data->update_lock);
 328
 329         /* Initialize the LM77 chip */
 330         lm77_init_client(new_client);
 331
 332         /* Register sysfs hooks */
 333         if ((err = sysfs_create_group(&new_client->dev.kobj, &lm77_group)))
 334                 goto exit_free;
 335
 336         data->hwmon_dev = hwmon_device_register(&new_client->dev);
 337         if (IS_ERR(data->hwmon_dev)) {
 338                 err = PTR_ERR(data->hwmon_dev);
 339                 goto exit_remove;
 340         }
 341
 342         return 0;
 343
 344 exit_remove:
 345         sysfs_remove_group(&new_client->dev.kobj, &lm77_group);
 346 exit_free:
 347         kfree(data);
 348 exit:
 349         return err;
 350 }
 351
 352 static int lm77_remove(struct i2c_client *client)
 353 {
 354         struct lm77_data *data = i2c_get_clientdata(client);
 355         hwmon_device_unregister(data->hwmon_dev);
 356         sysfs_remove_group(&client->dev.kobj, &lm77_group);
 357         kfree(data);
 358         return 0;
 359 }
 360
 361 /* All registers are word-sized, except for the configuration register.
 362    The LM77 uses the high-byte first convention. */
 363 static u16 lm77_read_value(struct i2c_client *client, u8 reg)
 364 {
 365         if (reg == LM77_REG_CONF)
 366                 return i2c_smbus_read_byte_data(client, reg);
 367         else
 368                 return i2c_smbus_read_word_swapped(client, reg);
 369 }
 370
 371 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value)
 372 {
 373         if (reg == LM77_REG_CONF)
 374                 return i2c_smbus_write_byte_data(client, reg, value);
 375         else
 376                 return i2c_smbus_write_word_swapped(client, reg, value);
 377 }
 378
 379 static void lm77_init_client(struct i2c_client *client)
 380 {
 381         /* Initialize the LM77 chip - turn off shutdown mode */
 382         int conf = lm77_read_value(client, LM77_REG_CONF);
 383         if (conf & 1)
 384                 lm77_write_value(client, LM77_REG_CONF, conf & 0xfe);
 385 }
 386
 387 static struct lm77_data *lm77_update_device(struct device *dev)
 388 {
 389         struct i2c_client *client = to_i2c_client(dev);
 390         struct lm77_data *data = i2c_get_clientdata(client);
 391
 392         mutex_lock(&data->update_lock);
 393
 394         if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
 395             || !data->valid) {
 396                 dev_dbg(&client->dev, "Starting lm77 update\n");
 397                 data->temp_input =
 398                         LM77_TEMP_FROM_REG(lm77_read_value(client,
 399                                                            LM77_REG_TEMP));
 400                 data->temp_hyst =
 401                         LM77_TEMP_FROM_REG(lm77_read_value(client,
 402                                                            LM77_REG_TEMP_HYST));
 403                 data->temp_crit =
 404                         LM77_TEMP_FROM_REG(lm77_read_value(client,
 405                                                            LM77_REG_TEMP_CRIT));
 406                 data->temp_min =
 407                         LM77_TEMP_FROM_REG(lm77_read_value(client,
 408                                                            LM77_REG_TEMP_MIN));
 409                 data->temp_max =
 410                         LM77_TEMP_FROM_REG(lm77_read_value(client,
 411                                                            LM77_REG_TEMP_MAX));
 412                 data->alarms =
 413                         lm77_read_value(client, LM77_REG_TEMP) & 0x0007;
 414                 data->last_updated = jiffies;
 415                 data->valid = 1;
 416         }
 417
 418         mutex_unlock(&data->update_lock);
 419
 420         return data;
 421 }
 422
 423 static int __init sensors_lm77_init(void)
 424 {
 425         return i2c_add_driver(&lm77_driver);
 426 }
 427
 428 static void __exit sensors_lm77_exit(void)
 429 {
 430         i2c_del_driver(&lm77_driver);
 431 }
 432
 433 MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>");
 434 MODULE_DESCRIPTION("LM77 driver");
 435 MODULE_LICENSE("GPL");
 436
 437 module_init(sensors_lm77_init);
 438 module_exit(sensors_lm77_exit);