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, struct i2c_board_info *info);
  70 static void lm77_init_client(struct i2c_client *client);
  71 static int lm77_remove(struct i2c_client *client);
  72 static u16 lm77_read_value(struct i2c_client *client, u8 reg);
  73 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value);
  74
  75 static struct lm77_data *lm77_update_device(struct device *dev);
  76
  77
  78 static const struct i2c_device_id lm77_id[] = {
  79         { "lm77", lm77 },
  80         { }
  81 };
  82 MODULE_DEVICE_TABLE(i2c, lm77_id);
  83
  84 /* This is the driver that will be inserted */
  85 static struct i2c_driver lm77_driver = {
  86         .class          = I2C_CLASS_HWMON,
  87         .driver = {
  88                 .name   = "lm77",
  89         },
  90         .probe          = lm77_probe,
  91         .remove         = lm77_remove,
  92         .id_table       = lm77_id,
  93         .detect         = lm77_detect,
  94         .address_list   = normal_i2c,
  95 };
  96
  97 /* straight from the datasheet */
  98 #define LM77_TEMP_MIN (-55000)
  99 #define LM77_TEMP_MAX 125000
 100
 101 /* In the temperature registers, the low 3 bits are not part of the
 102    temperature values; they are the status bits. */
 103 static inline s16 LM77_TEMP_TO_REG(int temp)
 104 {
 105         int ntemp = SENSORS_LIMIT(temp, LM77_TEMP_MIN, LM77_TEMP_MAX);
 106         return (ntemp / 500) * 8;
 107 }
 108
 109 static inline int LM77_TEMP_FROM_REG(s16 reg)
 110 {
 111         return (reg / 8) * 500;
 112 }
 113
 114 /* sysfs stuff */
 115
 116 /* read routines for temperature limits */
 117 #define show(value)     \
 118 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf)       \
 119 {                                                               \
 120         struct lm77_data *data = lm77_update_device(dev);       \
 121         return sprintf(buf, "%d\n", data->value);               \
 122 }
 123
 124 show(temp_input);
 125 show(temp_crit);
 126 show(temp_min);
 127 show(temp_max);
 128
 129 /* read routines for hysteresis values */
 130 static ssize_t show_temp_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf)
 131 {
 132         struct lm77_data *data = lm77_update_device(dev);
 133         return sprintf(buf, "%d\n", data->temp_crit - data->temp_hyst);
 134 }
 135 static ssize_t show_temp_min_hyst(struct device *dev, struct device_attribute *attr, char *buf)
 136 {
 137         struct lm77_data *data = lm77_update_device(dev);
 138         return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst);
 139 }
 140 static ssize_t show_temp_max_hyst(struct device *dev, struct device_attribute *attr, char *buf)
 141 {
 142         struct lm77_data *data = lm77_update_device(dev);
 143         return sprintf(buf, "%d\n", data->temp_max - data->temp_hyst);
 144 }
 145
 146 /* write routines */
 147 #define set(value, reg) \
 148 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)    \
 149 {                                                                               \
 150         struct i2c_client *client = to_i2c_client(dev);                         \
 151         struct lm77_data *data = i2c_get_clientdata(client);                    \
 152         long val = simple_strtol(buf, NULL, 10);                                \
 153                                                                                 \
 154         mutex_lock(&data->update_lock);                                         \
 155         data->value = val;                              \
 156         lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value));           \
 157         mutex_unlock(&data->update_lock);                                       \
 158         return count;                                                           \
 159 }
 160
 161 set(temp_min, LM77_REG_TEMP_MIN);
 162 set(temp_max, LM77_REG_TEMP_MAX);
 163
 164 /* hysteresis is stored as a relative value on the chip, so it has to be
 165    converted first */
 166 static ssize_t set_temp_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 167 {
 168         struct i2c_client *client = to_i2c_client(dev);
 169         struct lm77_data *data = i2c_get_clientdata(client);
 170         unsigned long val = simple_strtoul(buf, NULL, 10);
 171
 172         mutex_lock(&data->update_lock);
 173         data->temp_hyst = data->temp_crit - val;
 174         lm77_write_value(client, LM77_REG_TEMP_HYST,
 175                          LM77_TEMP_TO_REG(data->temp_hyst));
 176         mutex_unlock(&data->update_lock);
 177         return count;
 178 }
 179
 180 /* preserve hysteresis when setting T_crit */
 181 static ssize_t set_temp_crit(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 182 {
 183         struct i2c_client *client = to_i2c_client(dev);
 184         struct lm77_data *data = i2c_get_clientdata(client);
 185         long val = simple_strtoul(buf, NULL, 10);
 186         int oldcrithyst;
 187
 188         mutex_lock(&data->update_lock);
 189         oldcrithyst = data->temp_crit - data->temp_hyst;
 190         data->temp_crit = val;
 191         data->temp_hyst = data->temp_crit - oldcrithyst;
 192         lm77_write_value(client, LM77_REG_TEMP_CRIT,
 193                          LM77_TEMP_TO_REG(data->temp_crit));
 194         lm77_write_value(client, LM77_REG_TEMP_HYST,
 195                          LM77_TEMP_TO_REG(data->temp_hyst));
 196         mutex_unlock(&data->update_lock);
 197         return count;
 198 }
 199
 200 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
 201                           char *buf)
 202 {
 203         int bitnr = to_sensor_dev_attr(attr)->index;
 204         struct lm77_data *data = lm77_update_device(dev);
 205         return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1);
 206 }
 207
 208 static DEVICE_ATTR(temp1_input, S_IRUGO,
 209                    show_temp_input, NULL);
 210 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO,
 211                    show_temp_crit, set_temp_crit);
 212 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
 213                    show_temp_min, set_temp_min);
 214 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 215                    show_temp_max, set_temp_max);
 216
 217 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO,
 218                    show_temp_crit_hyst, set_temp_crit_hyst);
 219 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO,
 220                    show_temp_min_hyst, NULL);
 221 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO,
 222                    show_temp_max_hyst, NULL);
 223
 224 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
 225 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
 226 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);
 227
 228 static struct attribute *lm77_attributes[] = {
 229         &dev_attr_temp1_input.attr,
 230         &dev_attr_temp1_crit.attr,
 231         &dev_attr_temp1_min.attr,
 232         &dev_attr_temp1_max.attr,
 233         &dev_attr_temp1_crit_hyst.attr,
 234         &dev_attr_temp1_min_hyst.attr,
 235         &dev_attr_temp1_max_hyst.attr,
 236         &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
 237         &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 238         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 239         NULL
 240 };
 241
 242 static const struct attribute_group lm77_group = {
 243         .attrs = lm77_attributes,
 244 };
 245
 246 /* Return 0 if detection is successful, -ENODEV otherwise */
 247 static int lm77_detect(struct i2c_client *new_client,
 248                        struct i2c_board_info *info)
 249 {
 250         struct i2c_adapter *adapter = new_client->adapter;
 251         int i, cur, conf, hyst, crit, min, max;
 252
 253         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 254                                      I2C_FUNC_SMBUS_WORD_DATA))
 255                 return -ENODEV;
 256
 257         /* Here comes the remaining detection.  Since the LM77 has no
 258            register dedicated to identification, we have to rely on the
 259            following tricks:
 260
 261            1. the high 4 bits represent the sign and thus they should
 262               always be the same
 263            2. the high 3 bits are unused in the configuration register
 264            3. addresses 0x06 and 0x07 return the last read value
 265            4. registers cycling over 8-address boundaries
 266
 267            Word-sized registers are high-byte first. */
 268
 269         /* addresses cycling */
 270         cur = i2c_smbus_read_word_data(new_client, 0);
 271         conf = i2c_smbus_read_byte_data(new_client, 1);
 272         hyst = i2c_smbus_read_word_data(new_client, 2);
 273         crit = i2c_smbus_read_word_data(new_client, 3);
 274         min = i2c_smbus_read_word_data(new_client, 4);
 275         max = i2c_smbus_read_word_data(new_client, 5);
 276         for (i = 8; i <= 0xff; i += 8) {
 277                 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
 278                  || i2c_smbus_read_word_data(new_client, i + 2) != hyst
 279                  || i2c_smbus_read_word_data(new_client, i + 3) != crit
 280                  || i2c_smbus_read_word_data(new_client, i + 4) != min
 281                  || i2c_smbus_read_word_data(new_client, i + 5) != max)
 282                         return -ENODEV;
 283         }
 284
 285         /* sign bits */
 286         if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0)
 287          || ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0)
 288          || ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0)
 289          || ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0)
 290          || ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0))
 291                 return -ENODEV;
 292
 293         /* unused bits */
 294         if (conf & 0xe0)
 295                 return -ENODEV;
 296
 297         /* 0x06 and 0x07 return the last read value */
 298         cur = i2c_smbus_read_word_data(new_client, 0);
 299         if (i2c_smbus_read_word_data(new_client, 6) != cur
 300          || i2c_smbus_read_word_data(new_client, 7) != cur)
 301                 return -ENODEV;
 302         hyst = i2c_smbus_read_word_data(new_client, 2);
 303         if (i2c_smbus_read_word_data(new_client, 6) != hyst
 304          || i2c_smbus_read_word_data(new_client, 7) != hyst)
 305                 return -ENODEV;
 306         min = i2c_smbus_read_word_data(new_client, 4);
 307         if (i2c_smbus_read_word_data(new_client, 6) != min
 308          || i2c_smbus_read_word_data(new_client, 7) != min)
 309                 return -ENODEV;
 310
 311         strlcpy(info->type, "lm77", I2C_NAME_SIZE);
 312
 313         return 0;
 314 }
 315
 316 static int lm77_probe(struct i2c_client *new_client,
 317                       const struct i2c_device_id *id)
 318 {
 319         struct lm77_data *data;
 320         int err;
 321
 322         data = kzalloc(sizeof(struct lm77_data), GFP_KERNEL);
 323         if (!data) {
 324                 err = -ENOMEM;
 325                 goto exit;
 326         }
 327
 328         i2c_set_clientdata(new_client, data);
 329         data->valid = 0;
 330         mutex_init(&data->update_lock);
 331
 332         /* Initialize the LM77 chip */
 333         lm77_init_client(new_client);
 334
 335         /* Register sysfs hooks */
 336         if ((err = sysfs_create_group(&new_client->dev.kobj, &lm77_group)))
 337                 goto exit_free;
 338
 339         data->hwmon_dev = hwmon_device_register(&new_client->dev);
 340         if (IS_ERR(data->hwmon_dev)) {
 341                 err = PTR_ERR(data->hwmon_dev);
 342                 goto exit_remove;
 343         }
 344
 345         return 0;
 346
 347 exit_remove:
 348         sysfs_remove_group(&new_client->dev.kobj, &lm77_group);
 349 exit_free:
 350         kfree(data);
 351 exit:
 352         return err;
 353 }
 354
 355 static int lm77_remove(struct i2c_client *client)
 356 {
 357         struct lm77_data *data = i2c_get_clientdata(client);
 358         hwmon_device_unregister(data->hwmon_dev);
 359         sysfs_remove_group(&client->dev.kobj, &lm77_group);
 360         kfree(data);
 361         return 0;
 362 }
 363
 364 /* All registers are word-sized, except for the configuration register.
 365    The LM77 uses the high-byte first convention. */
 366 static u16 lm77_read_value(struct i2c_client *client, u8 reg)
 367 {
 368         if (reg == LM77_REG_CONF)
 369                 return i2c_smbus_read_byte_data(client, reg);
 370         else
 371                 return swab16(i2c_smbus_read_word_data(client, reg));
 372 }
 373
 374 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value)
 375 {
 376         if (reg == LM77_REG_CONF)
 377                 return i2c_smbus_write_byte_data(client, reg, value);
 378         else
 379                 return i2c_smbus_write_word_data(client, reg, swab16(value));
 380 }
 381
 382 static void lm77_init_client(struct i2c_client *client)
 383 {
 384         /* Initialize the LM77 chip - turn off shutdown mode */
 385         int conf = lm77_read_value(client, LM77_REG_CONF);
 386         if (conf & 1)
 387                 lm77_write_value(client, LM77_REG_CONF, conf & 0xfe);
 388 }
 389
 390 static struct lm77_data *lm77_update_device(struct device *dev)
 391 {
 392         struct i2c_client *client = to_i2c_client(dev);
 393         struct lm77_data *data = i2c_get_clientdata(client);
 394
 395         mutex_lock(&data->update_lock);
 396
 397         if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
 398             || !data->valid) {
 399                 dev_dbg(&client->dev, "Starting lm77 update\n");
 400                 data->temp_input =
 401                         LM77_TEMP_FROM_REG(lm77_read_value(client,
 402                                                            LM77_REG_TEMP));
 403                 data->temp_hyst =
 404                         LM77_TEMP_FROM_REG(lm77_read_value(client,
 405                                                            LM77_REG_TEMP_HYST));
 406                 data->temp_crit =
 407                         LM77_TEMP_FROM_REG(lm77_read_value(client,
 408                                                            LM77_REG_TEMP_CRIT));
 409                 data->temp_min =
 410                         LM77_TEMP_FROM_REG(lm77_read_value(client,
 411                                                            LM77_REG_TEMP_MIN));
 412                 data->temp_max =
 413                         LM77_TEMP_FROM_REG(lm77_read_value(client,
 414                                                            LM77_REG_TEMP_MAX));
 415                 data->alarms =
 416                         lm77_read_value(client, LM77_REG_TEMP) & 0x0007;
 417                 data->last_updated = jiffies;
 418                 data->valid = 1;
 419         }
 420
 421         mutex_unlock(&data->update_lock);
 422
 423         return data;
 424 }
 425
 426 static int __init sensors_lm77_init(void)
 427 {
 428         return i2c_add_driver(&lm77_driver);
 429 }
 430
 431 static void __exit sensors_lm77_exit(void)
 432 {
 433         i2c_del_driver(&lm77_driver);
 434 }
 435
 436 MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>");
 437 MODULE_DESCRIPTION("LM77 driver");
 438 MODULE_LICENSE("GPL");
 439
 440 module_init(sensors_lm77_init);
 441 module_exit(sensors_lm77_exit);