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         adt75,
  39         ds1775,
  40         ds75,
  41         lm75,
  42         lm75a,
  43         max6625,
  44         max6626,
  45         mcp980x,
  46         stds75,
  47         tcn75,
  48         tmp100,
  49         tmp101,
  50         tmp105,
  51         tmp175,
  52         tmp275,
  53         tmp75,
  54 };
  55
  56 /* Addresses scanned */
  57 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  58                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  59
  60
  61 /* The LM75 registers */
  62 #define LM75_REG_CONF           0x01
  63 static const u8 LM75_REG_TEMP[3] = {
  64         0x00,           /* input */
  65         0x03,           /* max */
  66         0x02,           /* hyst */
  67 };
  68
  69 /* Each client has this additional data */
  70 struct lm75_data {
  71         struct device           *hwmon_dev;
  72         struct mutex            update_lock;
  73         u8                      orig_conf;
  74         char                    valid;          /* !=0 if registers are valid */
  75         unsigned long           last_updated;   /* In jiffies */
  76         u16                     temp[3];        /* Register values,
  77                                                    0 = input
  78                                                    1 = max
  79                                                    2 = hyst */
  80 };
  81
  82 static int lm75_read_value(struct i2c_client *client, u8 reg);
  83 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
  84 static struct lm75_data *lm75_update_device(struct device *dev);
  85
  86
  87 /*-----------------------------------------------------------------------*/
  88
  89 /* sysfs attributes for hwmon */
  90
  91 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
  92                          char *buf)
  93 {
  94         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  95         struct lm75_data *data = lm75_update_device(dev);
  96         return sprintf(buf, "%d\n",
  97                        LM75_TEMP_FROM_REG(data->temp[attr->index]));
  98 }
  99
 100 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
 101                         const char *buf, size_t count)
 102 {
 103         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 104         struct i2c_client *client = to_i2c_client(dev);
 105         struct lm75_data *data = i2c_get_clientdata(client);
 106         int nr = attr->index;
 107         long temp;
 108         int error;
 109
 110         error = strict_strtol(buf, 10, &temp);
 111         if (error)
 112                 return error;
 113
 114         mutex_lock(&data->update_lock);
 115         data->temp[nr] = LM75_TEMP_TO_REG(temp);
 116         lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
 117         mutex_unlock(&data->update_lock);
 118         return count;
 119 }
 120
 121 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 122                         show_temp, set_temp, 1);
 123 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
 124                         show_temp, set_temp, 2);
 125 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 126
 127 static struct attribute *lm75_attributes[] = {
 128         &sensor_dev_attr_temp1_input.dev_attr.attr,
 129         &sensor_dev_attr_temp1_max.dev_attr.attr,
 130         &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 131
 132         NULL
 133 };
 134
 135 static const struct attribute_group lm75_group = {
 136         .attrs = lm75_attributes,
 137 };
 138
 139 /*-----------------------------------------------------------------------*/
 140
 141 /* device probe and removal */
 142
 143 static int
 144 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 145 {
 146         struct lm75_data *data;
 147         int status;
 148         u8 set_mask, clr_mask;
 149         int new;
 150
 151         if (!i2c_check_functionality(client->adapter,
 152                         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
 153                 return -EIO;
 154
 155         data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL);
 156         if (!data)
 157                 return -ENOMEM;
 158
 159         i2c_set_clientdata(client, data);
 160         mutex_init(&data->update_lock);
 161
 162         /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
 163          * Then tweak to be more precise when appropriate.
 164          */
 165         set_mask = 0;
 166         clr_mask = (1 << 0)                     /* continuous conversions */
 167                 | (1 << 6) | (1 << 5);          /* 9-bit mode */
 168
 169         /* configure as specified */
 170         status = lm75_read_value(client, LM75_REG_CONF);
 171         if (status < 0) {
 172                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 173                 goto exit_free;
 174         }
 175         data->orig_conf = status;
 176         new = status & ~clr_mask;
 177         new |= set_mask;
 178         if (status != new)
 179                 lm75_write_value(client, LM75_REG_CONF, new);
 180         dev_dbg(&client->dev, "Config %02x\n", new);
 181
 182         /* Register sysfs hooks */
 183         status = sysfs_create_group(&client->dev.kobj, &lm75_group);
 184         if (status)
 185                 goto exit_free;
 186
 187         data->hwmon_dev = hwmon_device_register(&client->dev);
 188         if (IS_ERR(data->hwmon_dev)) {
 189                 status = PTR_ERR(data->hwmon_dev);
 190                 goto exit_remove;
 191         }
 192
 193         dev_info(&client->dev, "%s: sensor '%s'\n",
 194                  dev_name(data->hwmon_dev), client->name);
 195
 196         return 0;
 197
 198 exit_remove:
 199         sysfs_remove_group(&client->dev.kobj, &lm75_group);
 200 exit_free:
 201         kfree(data);
 202         return status;
 203 }
 204
 205 static int lm75_remove(struct i2c_client *client)
 206 {
 207         struct lm75_data *data = i2c_get_clientdata(client);
 208
 209         hwmon_device_unregister(data->hwmon_dev);
 210         sysfs_remove_group(&client->dev.kobj, &lm75_group);
 211         lm75_write_value(client, LM75_REG_CONF, data->orig_conf);
 212         kfree(data);
 213         return 0;
 214 }
 215
 216 static const struct i2c_device_id lm75_ids[] = {
 217         { "adt75", adt75, },
 218         { "ds1775", ds1775, },
 219         { "ds75", ds75, },
 220         { "lm75", lm75, },
 221         { "lm75a", lm75a, },
 222         { "max6625", max6625, },
 223         { "max6626", max6626, },
 224         { "mcp980x", mcp980x, },
 225         { "stds75", stds75, },
 226         { "tcn75", tcn75, },
 227         { "tmp100", tmp100, },
 228         { "tmp101", tmp101, },
 229         { "tmp105", tmp105, },
 230         { "tmp175", tmp175, },
 231         { "tmp275", tmp275, },
 232         { "tmp75", tmp75, },
 233         { /* LIST END */ }
 234 };
 235 MODULE_DEVICE_TABLE(i2c, lm75_ids);
 236
 237 #define LM75A_ID 0xA1
 238
 239 /* Return 0 if detection is successful, -ENODEV otherwise */
 240 static int lm75_detect(struct i2c_client *new_client,
 241                        struct i2c_board_info *info)
 242 {
 243         struct i2c_adapter *adapter = new_client->adapter;
 244         int i;
 245         int conf, hyst, os;
 246         bool is_lm75a = 0;
 247
 248         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 249                                      I2C_FUNC_SMBUS_WORD_DATA))
 250                 return -ENODEV;
 251
 252         /*
 253          * Now, we do the remaining detection. There is no identification-
 254          * dedicated register so we have to rely on several tricks:
 255          * unused bits, registers cycling over 8-address boundaries,
 256          * addresses 0x04-0x07 returning the last read value.
 257          * The cycling+unused addresses combination is not tested,
 258          * since it would significantly slow the detection down and would
 259          * hardly add any value.
 260          *
 261          * The National Semiconductor LM75A is different than earlier
 262          * LM75s.  It has an ID byte of 0xaX (where X is the chip
 263          * revision, with 1 being the only revision in existence) in
 264          * register 7, and unused registers return 0xff rather than the
 265          * last read value.
 266          *
 267          * Note that this function only detects the original National
 268          * Semiconductor LM75 and the LM75A. Clones from other vendors
 269          * aren't detected, on purpose, because they are typically never
 270          * found on PC hardware. They are found on embedded designs where
 271          * they can be instantiated explicitly so detection is not needed.
 272          * The absence of identification registers on all these clones
 273          * would make their exhaustive detection very difficult and weak,
 274          * and odds are that the driver would bind to unsupported devices.
 275          */
 276
 277         /* Unused bits */
 278         conf = i2c_smbus_read_byte_data(new_client, 1);
 279         if (conf & 0xe0)
 280                 return -ENODEV;
 281
 282         /* First check for LM75A */
 283         if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
 284                 /* LM75A returns 0xff on unused registers so
 285                    just to be sure we check for that too. */
 286                 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
 287                  || i2c_smbus_read_byte_data(new_client, 5) != 0xff
 288                  || i2c_smbus_read_byte_data(new_client, 6) != 0xff)
 289                         return -ENODEV;
 290                 is_lm75a = 1;
 291                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 292                 os = i2c_smbus_read_byte_data(new_client, 3);
 293         } else { /* Traditional style LM75 detection */
 294                 /* Unused addresses */
 295                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 296                 if (i2c_smbus_read_byte_data(new_client, 4) != hyst
 297                  || i2c_smbus_read_byte_data(new_client, 5) != hyst
 298                  || i2c_smbus_read_byte_data(new_client, 6) != hyst
 299                  || i2c_smbus_read_byte_data(new_client, 7) != hyst)
 300                         return -ENODEV;
 301                 os = i2c_smbus_read_byte_data(new_client, 3);
 302                 if (i2c_smbus_read_byte_data(new_client, 4) != os
 303                  || i2c_smbus_read_byte_data(new_client, 5) != os
 304                  || i2c_smbus_read_byte_data(new_client, 6) != os
 305                  || i2c_smbus_read_byte_data(new_client, 7) != os)
 306                         return -ENODEV;
 307         }
 308
 309         /* Addresses cycling */
 310         for (i = 8; i <= 248; i += 40) {
 311                 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
 312                  || i2c_smbus_read_byte_data(new_client, i + 2) != hyst
 313                  || i2c_smbus_read_byte_data(new_client, i + 3) != os)
 314                         return -ENODEV;
 315                 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
 316                                 != LM75A_ID)
 317                         return -ENODEV;
 318         }
 319
 320         strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
 321
 322         return 0;
 323 }
 324
 325 #ifdef CONFIG_PM
 326 static int lm75_suspend(struct device *dev)
 327 {
 328         int status;
 329         struct i2c_client *client = to_i2c_client(dev);
 330         status = lm75_read_value(client, LM75_REG_CONF);
 331         if (status < 0) {
 332                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 333                 return status;
 334         }
 335         status = status | LM75_SHUTDOWN;
 336         lm75_write_value(client, LM75_REG_CONF, status);
 337         return 0;
 338 }
 339
 340 static int lm75_resume(struct device *dev)
 341 {
 342         int status;
 343         struct i2c_client *client = to_i2c_client(dev);
 344         status = lm75_read_value(client, LM75_REG_CONF);
 345         if (status < 0) {
 346                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 347                 return status;
 348         }
 349         status = status & ~LM75_SHUTDOWN;
 350         lm75_write_value(client, LM75_REG_CONF, status);
 351         return 0;
 352 }
 353
 354 static const struct dev_pm_ops lm75_dev_pm_ops = {
 355         .suspend        = lm75_suspend,
 356         .resume         = lm75_resume,
 357 };
 358 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
 359 #else
 360 #define LM75_DEV_PM_OPS NULL
 361 #endif /* CONFIG_PM */
 362
 363 static struct i2c_driver lm75_driver = {
 364         .class          = I2C_CLASS_HWMON,
 365         .driver = {
 366                 .name   = "lm75",
 367                 .pm     = LM75_DEV_PM_OPS,
 368         },
 369         .probe          = lm75_probe,
 370         .remove         = lm75_remove,
 371         .id_table       = lm75_ids,
 372         .detect         = lm75_detect,
 373         .address_list   = normal_i2c,
 374 };
 375
 376 /*-----------------------------------------------------------------------*/
 377
 378 /* register access */
 379
 380 /*
 381  * All registers are word-sized, except for the configuration register.
 382  * LM75 uses a high-byte first convention, which is exactly opposite to
 383  * the SMBus standard.
 384  */
 385 static int lm75_read_value(struct i2c_client *client, u8 reg)
 386 {
 387         if (reg == LM75_REG_CONF)
 388                 return i2c_smbus_read_byte_data(client, reg);
 389         else
 390                 return i2c_smbus_read_word_swapped(client, reg);
 391 }
 392
 393 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
 394 {
 395         if (reg == LM75_REG_CONF)
 396                 return i2c_smbus_write_byte_data(client, reg, value);
 397         else
 398                 return i2c_smbus_write_word_swapped(client, reg, value);
 399 }
 400
 401 static struct lm75_data *lm75_update_device(struct device *dev)
 402 {
 403         struct i2c_client *client = to_i2c_client(dev);
 404         struct lm75_data *data = i2c_get_clientdata(client);
 405
 406         mutex_lock(&data->update_lock);
 407
 408         if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
 409             || !data->valid) {
 410                 int i;
 411                 dev_dbg(&client->dev, "Starting lm75 update\n");
 412
 413                 for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
 414                         int status;
 415
 416                         status = lm75_read_value(client, LM75_REG_TEMP[i]);
 417                         if (status < 0)
 418                                 dev_dbg(&client->dev, "reg %d, err %d\n",
 419                                                 LM75_REG_TEMP[i], status);
 420                         else
 421                                 data->temp[i] = status;
 422                 }
 423                 data->last_updated = jiffies;
 424                 data->valid = 1;
 425         }
 426
 427         mutex_unlock(&data->update_lock);
 428
 429         return data;
 430 }
 431
 432 /*-----------------------------------------------------------------------*/
 433
 434 /* module glue */
 435
 436 static int __init sensors_lm75_init(void)
 437 {
 438         return i2c_add_driver(&lm75_driver);
 439 }
 440
 441 static void __exit sensors_lm75_exit(void)
 442 {
 443         i2c_del_driver(&lm75_driver);
 444 }
 445
 446 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
 447 MODULE_DESCRIPTION("LM75 driver");
 448 MODULE_LICENSE("GPL");
 449
 450 module_init(sensors_lm75_init);
 451 module_exit(sensors_lm75_exit);