drivers/hwmon/lm75.c

   1 /*
   2  * lm75.c - Part of lm_sensors, Linux kernel modules for hardware
   3  *       monitoring
   4  * Copyright (c) 1998, 1999  Frodo Looijaard <frodol@dds.nl>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/init.h>
  23 #include <linux/slab.h>
  24 #include <linux/jiffies.h>
  25 #include <linux/i2c.h>
  26 #include <linux/hwmon.h>
  27 #include <linux/hwmon-sysfs.h>
  28 #include <linux/err.h>
  29 #include <linux/mutex.h>
  30 #include "lm75.h"
  31
  32
  33 /*
  34  * This driver handles the LM75 and compatible digital temperature sensors.
  35  */
  36
  37 enum lm75_type {                /* keep sorted in alphabetical order */
  38         ds1775,
  39         ds75,
  40         lm75,
  41         lm75a,
  42         max6625,
  43         max6626,
  44         mcp980x,
  45         stds75,
  46         tcn75,
  47         tmp100,
  48         tmp101,
  49         tmp105,
  50         tmp175,
  51         tmp275,
  52         tmp75,
  53 };
  54
  55 /* Addresses scanned */
  56 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  57                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  58
  59
  60 /* The LM75 registers */
  61 #define LM75_REG_CONF           0x01
  62 static const u8 LM75_REG_TEMP[3] = {
  63         0x00,           /* input */
  64         0x03,           /* max */
  65         0x02,           /* hyst */
  66 };
  67
  68 /* Each client has this additional data */
  69 struct lm75_data {
  70         struct device           *hwmon_dev;
  71         struct mutex            update_lock;
  72         u8                      orig_conf;
  73         char                    valid;          /* !=0 if registers are valid */
  74         unsigned long           last_updated;   /* In jiffies */
  75         u16                     temp[3];        /* Register values,
  76                                                    0 = input
  77                                                    1 = max
  78                                                    2 = hyst */
  79 };
  80
  81 static int lm75_read_value(struct i2c_client *client, u8 reg);
  82 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
  83 static struct lm75_data *lm75_update_device(struct device *dev);
  84
  85
  86 /*-----------------------------------------------------------------------*/
  87
  88 /* sysfs attributes for hwmon */
  89
  90 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
  91                          char *buf)
  92 {
  93         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  94         struct lm75_data *data = lm75_update_device(dev);
  95         return sprintf(buf, "%d\n",
  96                        LM75_TEMP_FROM_REG(data->temp[attr->index]));
  97 }
  98
  99 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
 100                         const char *buf, size_t count)
 101 {
 102         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 103         struct i2c_client *client = to_i2c_client(dev);
 104         struct lm75_data *data = i2c_get_clientdata(client);
 105         int nr = attr->index;
 106         long temp;
 107         int error;
 108
 109         error = strict_strtol(buf, 10, &temp);
 110         if (error)
 111                 return error;
 112
 113         mutex_lock(&data->update_lock);
 114         data->temp[nr] = LM75_TEMP_TO_REG(temp);
 115         lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
 116         mutex_unlock(&data->update_lock);
 117         return count;
 118 }
 119
 120 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 121                         show_temp, set_temp, 1);
 122 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
 123                         show_temp, set_temp, 2);
 124 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 125
 126 static struct attribute *lm75_attributes[] = {
 127         &sensor_dev_attr_temp1_input.dev_attr.attr,
 128         &sensor_dev_attr_temp1_max.dev_attr.attr,
 129         &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 130
 131         NULL
 132 };
 133
 134 static const struct attribute_group lm75_group = {
 135         .attrs = lm75_attributes,
 136 };
 137
 138 /*-----------------------------------------------------------------------*/
 139
 140 /* device probe and removal */
 141
 142 static int
 143 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 144 {
 145         struct lm75_data *data;
 146         int status;
 147         u8 set_mask, clr_mask;
 148         int new;
 149
 150         if (!i2c_check_functionality(client->adapter,
 151                         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
 152                 return -EIO;
 153
 154         data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL);
 155         if (!data)
 156                 return -ENOMEM;
 157
 158         i2c_set_clientdata(client, data);
 159         mutex_init(&data->update_lock);
 160
 161         /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
 162          * Then tweak to be more precise when appropriate.
 163          */
 164         set_mask = 0;
 165         clr_mask = (1 << 0)                     /* continuous conversions */
 166                 | (1 << 6) | (1 << 5);          /* 9-bit mode */
 167
 168         /* configure as specified */
 169         status = lm75_read_value(client, LM75_REG_CONF);
 170         if (status < 0) {
 171                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 172                 goto exit_free;
 173         }
 174         data->orig_conf = status;
 175         new = status & ~clr_mask;
 176         new |= set_mask;
 177         if (status != new)
 178                 lm75_write_value(client, LM75_REG_CONF, new);
 179         dev_dbg(&client->dev, "Config %02x\n", new);
 180
 181         /* Register sysfs hooks */
 182         status = sysfs_create_group(&client->dev.kobj, &lm75_group);
 183         if (status)
 184                 goto exit_free;
 185
 186         data->hwmon_dev = hwmon_device_register(&client->dev);
 187         if (IS_ERR(data->hwmon_dev)) {
 188                 status = PTR_ERR(data->hwmon_dev);
 189                 goto exit_remove;
 190         }
 191
 192         dev_info(&client->dev, "%s: sensor '%s'\n",
 193                  dev_name(data->hwmon_dev), client->name);
 194
 195         return 0;
 196
 197 exit_remove:
 198         sysfs_remove_group(&client->dev.kobj, &lm75_group);
 199 exit_free:
 200         kfree(data);
 201         return status;
 202 }
 203
 204 static int lm75_remove(struct i2c_client *client)
 205 {
 206         struct lm75_data *data = i2c_get_clientdata(client);
 207
 208         hwmon_device_unregister(data->hwmon_dev);
 209         sysfs_remove_group(&client->dev.kobj, &lm75_group);
 210         lm75_write_value(client, LM75_REG_CONF, data->orig_conf);
 211         kfree(data);
 212         return 0;
 213 }
 214
 215 static const struct i2c_device_id lm75_ids[] = {
 216         { "ds1775", ds1775, },
 217         { "ds75", ds75, },
 218         { "lm75", lm75, },
 219         { "lm75a", lm75a, },
 220         { "max6625", max6625, },
 221         { "max6626", max6626, },
 222         { "mcp980x", mcp980x, },
 223         { "stds75", stds75, },
 224         { "tcn75", tcn75, },
 225         { "tmp100", tmp100, },
 226         { "tmp101", tmp101, },
 227         { "tmp105", tmp105, },
 228         { "tmp175", tmp175, },
 229         { "tmp275", tmp275, },
 230         { "tmp75", tmp75, },
 231         { /* LIST END */ }
 232 };
 233 MODULE_DEVICE_TABLE(i2c, lm75_ids);
 234
 235 /* Return 0 if detection is successful, -ENODEV otherwise */
 236 static int lm75_detect(struct i2c_client *new_client,
 237                        struct i2c_board_info *info)
 238 {
 239         struct i2c_adapter *adapter = new_client->adapter;
 240         int i;
 241         int cur, conf, hyst, os;
 242
 243         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 244                                      I2C_FUNC_SMBUS_WORD_DATA))
 245                 return -ENODEV;
 246
 247         /* Now, we do the remaining detection. There is no identification-
 248            dedicated register so we have to rely on several tricks:
 249            unused bits, registers cycling over 8-address boundaries,
 250            addresses 0x04-0x07 returning the last read value.
 251            The cycling+unused addresses combination is not tested,
 252            since it would significantly slow the detection down and would
 253            hardly add any value. */
 254
 255         /* Unused addresses */
 256         cur = i2c_smbus_read_word_data(new_client, 0);
 257         conf = i2c_smbus_read_byte_data(new_client, 1);
 258         hyst = i2c_smbus_read_word_data(new_client, 2);
 259         if (i2c_smbus_read_word_data(new_client, 4) != hyst
 260          || i2c_smbus_read_word_data(new_client, 5) != hyst
 261          || i2c_smbus_read_word_data(new_client, 6) != hyst
 262          || i2c_smbus_read_word_data(new_client, 7) != hyst)
 263                 return -ENODEV;
 264         os = i2c_smbus_read_word_data(new_client, 3);
 265         if (i2c_smbus_read_word_data(new_client, 4) != os
 266          || i2c_smbus_read_word_data(new_client, 5) != os
 267          || i2c_smbus_read_word_data(new_client, 6) != os
 268          || i2c_smbus_read_word_data(new_client, 7) != os)
 269                 return -ENODEV;
 270
 271         /* Unused bits */
 272         if (conf & 0xe0)
 273                 return -ENODEV;
 274
 275         /* Addresses cycling */
 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) != os)
 280                         return -ENODEV;
 281         }
 282
 283         strlcpy(info->type, "lm75", I2C_NAME_SIZE);
 284
 285         return 0;
 286 }
 287
 288 #ifdef CONFIG_PM
 289 static int lm75_suspend(struct device *dev)
 290 {
 291         int status;
 292         struct i2c_client *client = to_i2c_client(dev);
 293         status = lm75_read_value(client, LM75_REG_CONF);
 294         if (status < 0) {
 295                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 296                 return status;
 297         }
 298         status = status | LM75_SHUTDOWN;
 299         lm75_write_value(client, LM75_REG_CONF, status);
 300         return 0;
 301 }
 302
 303 static int lm75_resume(struct device *dev)
 304 {
 305         int status;
 306         struct i2c_client *client = to_i2c_client(dev);
 307         status = lm75_read_value(client, LM75_REG_CONF);
 308         if (status < 0) {
 309                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 310                 return status;
 311         }
 312         status = status & ~LM75_SHUTDOWN;
 313         lm75_write_value(client, LM75_REG_CONF, status);
 314         return 0;
 315 }
 316
 317 static const struct dev_pm_ops lm75_dev_pm_ops = {
 318         .suspend        = lm75_suspend,
 319         .resume         = lm75_resume,
 320 };
 321 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
 322 #else
 323 #define LM75_DEV_PM_OPS NULL
 324 #endif /* CONFIG_PM */
 325
 326 static struct i2c_driver lm75_driver = {
 327         .class          = I2C_CLASS_HWMON,
 328         .driver = {
 329                 .name   = "lm75",
 330                 .pm     = LM75_DEV_PM_OPS,
 331         },
 332         .probe          = lm75_probe,
 333         .remove         = lm75_remove,
 334         .id_table       = lm75_ids,
 335         .detect         = lm75_detect,
 336         .address_list   = normal_i2c,
 337 };
 338
 339 /*-----------------------------------------------------------------------*/
 340
 341 /* register access */
 342
 343 /*
 344  * All registers are word-sized, except for the configuration register.
 345  * LM75 uses a high-byte first convention, which is exactly opposite to
 346  * the SMBus standard.
 347  */
 348 static int lm75_read_value(struct i2c_client *client, u8 reg)
 349 {
 350         int value;
 351
 352         if (reg == LM75_REG_CONF)
 353                 return i2c_smbus_read_byte_data(client, reg);
 354
 355         value = i2c_smbus_read_word_data(client, reg);
 356         return (value < 0) ? value : swab16(value);
 357 }
 358
 359 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
 360 {
 361         if (reg == LM75_REG_CONF)
 362                 return i2c_smbus_write_byte_data(client, reg, value);
 363         else
 364                 return i2c_smbus_write_word_data(client, reg, swab16(value));
 365 }
 366
 367 static struct lm75_data *lm75_update_device(struct device *dev)
 368 {
 369         struct i2c_client *client = to_i2c_client(dev);
 370         struct lm75_data *data = i2c_get_clientdata(client);
 371
 372         mutex_lock(&data->update_lock);
 373
 374         if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
 375             || !data->valid) {
 376                 int i;
 377                 dev_dbg(&client->dev, "Starting lm75 update\n");
 378
 379                 for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
 380                         int status;
 381
 382                         status = lm75_read_value(client, LM75_REG_TEMP[i]);
 383                         if (status < 0)
 384                                 dev_dbg(&client->dev, "reg %d, err %d\n",
 385                                                 LM75_REG_TEMP[i], status);
 386                         else
 387                                 data->temp[i] = status;
 388                 }
 389                 data->last_updated = jiffies;
 390                 data->valid = 1;
 391         }
 392
 393         mutex_unlock(&data->update_lock);
 394
 395         return data;
 396 }
 397
 398 /*-----------------------------------------------------------------------*/
 399
 400 /* module glue */
 401
 402 static int __init sensors_lm75_init(void)
 403 {
 404         return i2c_add_driver(&lm75_driver);
 405 }
 406
 407 static void __exit sensors_lm75_exit(void)
 408 {
 409         i2c_del_driver(&lm75_driver);
 410 }
 411
 412 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
 413 MODULE_DESCRIPTION("LM75 driver");
 414 MODULE_LICENSE("GPL");
 415
 416 module_init(sensors_lm75_init);
 417 module_exit(sensors_lm75_exit);