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         ds7505,
  42         lm75,
  43         lm75a,
  44         max6625,
  45         max6626,
  46         mcp980x,
  47         stds75,
  48         tcn75,
  49         tmp100,
  50         tmp101,
  51         tmp105,
  52         tmp175,
  53         tmp275,
  54         tmp75,
  55 };
  56
  57 /* Addresses scanned */
  58 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  59                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  60
  61
  62 /* The LM75 registers */
  63 #define LM75_REG_CONF           0x01
  64 static const u8 LM75_REG_TEMP[3] = {
  65         0x00,           /* input */
  66         0x03,           /* max */
  67         0x02,           /* hyst */
  68 };
  69
  70 /* Each client has this additional data */
  71 struct lm75_data {
  72         struct device           *hwmon_dev;
  73         struct mutex            update_lock;
  74         u8                      orig_conf;
  75         u8                      resolution;     /* In bits, between 9 and 12 */
  76         u8                      resolution_limits;
  77         char                    valid;          /* !=0 if registers are valid */
  78         unsigned long           last_updated;   /* In jiffies */
  79         unsigned long           sample_time;    /* In jiffies */
  80         s16                     temp[3];        /* Register values,
  81                                                    0 = input
  82                                                    1 = max
  83                                                    2 = hyst */
  84 };
  85
  86 static int lm75_read_value(struct i2c_client *client, u8 reg);
  87 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
  88 static struct lm75_data *lm75_update_device(struct device *dev);
  89
  90
  91 /*-----------------------------------------------------------------------*/
  92
  93 /* sysfs attributes for hwmon */
  94
  95 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
  96                          char *buf)
  97 {
  98         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  99         struct lm75_data *data = lm75_update_device(dev);
 100         long temp;
 101
 102         if (IS_ERR(data))
 103                 return PTR_ERR(data);
 104
 105         temp = ((data->temp[attr->index] >> (16 - data->resolution)) * 1000)
 106                >> (data->resolution - 8);
 107
 108         return sprintf(buf, "%ld\n", temp);
 109 }
 110
 111 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
 112                         const char *buf, size_t count)
 113 {
 114         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 115         struct i2c_client *client = to_i2c_client(dev);
 116         struct lm75_data *data = i2c_get_clientdata(client);
 117         int nr = attr->index;
 118         long temp;
 119         int error;
 120         u8 resolution;
 121
 122         error = kstrtol(buf, 10, &temp);
 123         if (error)
 124                 return error;
 125
 126         /*
 127          * Resolution of limit registers is assumed to be the same as the
 128          * temperature input register resolution unless given explicitly.
 129          */
 130         if (attr->index && data->resolution_limits)
 131                 resolution = data->resolution_limits;
 132         else
 133                 resolution = data->resolution;
 134
 135         mutex_lock(&data->update_lock);
 136         temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
 137         data->temp[nr] = DIV_ROUND_CLOSEST(temp  << (resolution - 8),
 138                                            1000) << (16 - resolution);
 139         lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
 140         mutex_unlock(&data->update_lock);
 141         return count;
 142 }
 143
 144 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 145                         show_temp, set_temp, 1);
 146 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
 147                         show_temp, set_temp, 2);
 148 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 149
 150 static struct attribute *lm75_attributes[] = {
 151         &sensor_dev_attr_temp1_input.dev_attr.attr,
 152         &sensor_dev_attr_temp1_max.dev_attr.attr,
 153         &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 154
 155         NULL
 156 };
 157
 158 static const struct attribute_group lm75_group = {
 159         .attrs = lm75_attributes,
 160 };
 161
 162 /*-----------------------------------------------------------------------*/
 163
 164 /* device probe and removal */
 165
 166 static int
 167 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 168 {
 169         struct lm75_data *data;
 170         int status;
 171         u8 set_mask, clr_mask;
 172         int new;
 173         enum lm75_type kind = id->driver_data;
 174
 175         if (!i2c_check_functionality(client->adapter,
 176                         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
 177                 return -EIO;
 178
 179         data = devm_kzalloc(&client->dev, sizeof(struct lm75_data), GFP_KERNEL);
 180         if (!data)
 181                 return -ENOMEM;
 182
 183         i2c_set_clientdata(client, data);
 184         mutex_init(&data->update_lock);
 185
 186         /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
 187          * Then tweak to be more precise when appropriate.
 188          */
 189         set_mask = 0;
 190         clr_mask = LM75_SHUTDOWN;               /* continuous conversions */
 191
 192         switch (kind) {
 193         case adt75:
 194                 clr_mask |= 1 << 5;             /* not one-shot mode */
 195                 data->resolution = 12;
 196                 data->sample_time = HZ / 8;
 197                 break;
 198         case ds1775:
 199         case ds75:
 200         case stds75:
 201                 clr_mask |= 3 << 5;
 202                 set_mask |= 2 << 5;             /* 11-bit mode */
 203                 data->resolution = 11;
 204                 data->sample_time = HZ;
 205                 break;
 206         case ds7505:
 207                 set_mask |= 3 << 5;             /* 12-bit mode */
 208                 data->resolution = 12;
 209                 data->sample_time = HZ / 4;
 210                 break;
 211         case lm75:
 212         case lm75a:
 213                 data->resolution = 9;
 214                 data->sample_time = HZ / 2;
 215                 break;
 216         case max6625:
 217                 data->resolution = 9;
 218                 data->sample_time = HZ / 4;
 219                 break;
 220         case max6626:
 221                 data->resolution = 12;
 222                 data->resolution_limits = 9;
 223                 data->sample_time = HZ / 4;
 224                 break;
 225         case tcn75:
 226                 data->resolution = 9;
 227                 data->sample_time = HZ / 8;
 228                 break;
 229         case mcp980x:
 230                 data->resolution_limits = 9;
 231                 /* fall through */
 232         case tmp100:
 233         case tmp101:
 234                 set_mask |= 3 << 5;             /* 12-bit mode */
 235                 data->resolution = 12;
 236                 data->sample_time = HZ;
 237                 clr_mask |= 1 << 7;             /* not one-shot mode */
 238                 break;
 239         case tmp105:
 240         case tmp175:
 241         case tmp275:
 242         case tmp75:
 243                 set_mask |= 3 << 5;             /* 12-bit mode */
 244                 clr_mask |= 1 << 7;             /* not one-shot mode */
 245                 data->resolution = 12;
 246                 data->sample_time = HZ / 2;
 247                 break;
 248         }
 249
 250         /* configure as specified */
 251         status = lm75_read_value(client, LM75_REG_CONF);
 252         if (status < 0) {
 253                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 254                 return status;
 255         }
 256         data->orig_conf = status;
 257         new = status & ~clr_mask;
 258         new |= set_mask;
 259         if (status != new)
 260                 lm75_write_value(client, LM75_REG_CONF, new);
 261         dev_dbg(&client->dev, "Config %02x\n", new);
 262
 263         /* Register sysfs hooks */
 264         status = sysfs_create_group(&client->dev.kobj, &lm75_group);
 265         if (status)
 266                 return status;
 267
 268         data->hwmon_dev = hwmon_device_register(&client->dev);
 269         if (IS_ERR(data->hwmon_dev)) {
 270                 status = PTR_ERR(data->hwmon_dev);
 271                 goto exit_remove;
 272         }
 273
 274         dev_info(&client->dev, "%s: sensor '%s'\n",
 275                  dev_name(data->hwmon_dev), client->name);
 276
 277         return 0;
 278
 279 exit_remove:
 280         sysfs_remove_group(&client->dev.kobj, &lm75_group);
 281         return status;
 282 }
 283
 284 static int lm75_remove(struct i2c_client *client)
 285 {
 286         struct lm75_data *data = i2c_get_clientdata(client);
 287
 288         hwmon_device_unregister(data->hwmon_dev);
 289         sysfs_remove_group(&client->dev.kobj, &lm75_group);
 290         lm75_write_value(client, LM75_REG_CONF, data->orig_conf);
 291         return 0;
 292 }
 293
 294 static const struct i2c_device_id lm75_ids[] = {
 295         { "adt75", adt75, },
 296         { "ds1775", ds1775, },
 297         { "ds75", ds75, },
 298         { "ds7505", ds7505, },
 299         { "lm75", lm75, },
 300         { "lm75a", lm75a, },
 301         { "max6625", max6625, },
 302         { "max6626", max6626, },
 303         { "mcp980x", mcp980x, },
 304         { "stds75", stds75, },
 305         { "tcn75", tcn75, },
 306         { "tmp100", tmp100, },
 307         { "tmp101", tmp101, },
 308         { "tmp105", tmp105, },
 309         { "tmp175", tmp175, },
 310         { "tmp275", tmp275, },
 311         { "tmp75", tmp75, },
 312         { /* LIST END */ }
 313 };
 314 MODULE_DEVICE_TABLE(i2c, lm75_ids);
 315
 316 #define LM75A_ID 0xA1
 317
 318 /* Return 0 if detection is successful, -ENODEV otherwise */
 319 static int lm75_detect(struct i2c_client *new_client,
 320                        struct i2c_board_info *info)
 321 {
 322         struct i2c_adapter *adapter = new_client->adapter;
 323         int i;
 324         int conf, hyst, os;
 325         bool is_lm75a = 0;
 326
 327         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 328                                      I2C_FUNC_SMBUS_WORD_DATA))
 329                 return -ENODEV;
 330
 331         /*
 332          * Now, we do the remaining detection. There is no identification-
 333          * dedicated register so we have to rely on several tricks:
 334          * unused bits, registers cycling over 8-address boundaries,
 335          * addresses 0x04-0x07 returning the last read value.
 336          * The cycling+unused addresses combination is not tested,
 337          * since it would significantly slow the detection down and would
 338          * hardly add any value.
 339          *
 340          * The National Semiconductor LM75A is different than earlier
 341          * LM75s.  It has an ID byte of 0xaX (where X is the chip
 342          * revision, with 1 being the only revision in existence) in
 343          * register 7, and unused registers return 0xff rather than the
 344          * last read value.
 345          *
 346          * Note that this function only detects the original National
 347          * Semiconductor LM75 and the LM75A. Clones from other vendors
 348          * aren't detected, on purpose, because they are typically never
 349          * found on PC hardware. They are found on embedded designs where
 350          * they can be instantiated explicitly so detection is not needed.
 351          * The absence of identification registers on all these clones
 352          * would make their exhaustive detection very difficult and weak,
 353          * and odds are that the driver would bind to unsupported devices.
 354          */
 355
 356         /* Unused bits */
 357         conf = i2c_smbus_read_byte_data(new_client, 1);
 358         if (conf & 0xe0)
 359                 return -ENODEV;
 360
 361         /* First check for LM75A */
 362         if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
 363                 /* LM75A returns 0xff on unused registers so
 364                    just to be sure we check for that too. */
 365                 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
 366                  || i2c_smbus_read_byte_data(new_client, 5) != 0xff
 367                  || i2c_smbus_read_byte_data(new_client, 6) != 0xff)
 368                         return -ENODEV;
 369                 is_lm75a = 1;
 370                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 371                 os = i2c_smbus_read_byte_data(new_client, 3);
 372         } else { /* Traditional style LM75 detection */
 373                 /* Unused addresses */
 374                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 375                 if (i2c_smbus_read_byte_data(new_client, 4) != hyst
 376                  || i2c_smbus_read_byte_data(new_client, 5) != hyst
 377                  || i2c_smbus_read_byte_data(new_client, 6) != hyst
 378                  || i2c_smbus_read_byte_data(new_client, 7) != hyst)
 379                         return -ENODEV;
 380                 os = i2c_smbus_read_byte_data(new_client, 3);
 381                 if (i2c_smbus_read_byte_data(new_client, 4) != os
 382                  || i2c_smbus_read_byte_data(new_client, 5) != os
 383                  || i2c_smbus_read_byte_data(new_client, 6) != os
 384                  || i2c_smbus_read_byte_data(new_client, 7) != os)
 385                         return -ENODEV;
 386         }
 387
 388         /* Addresses cycling */
 389         for (i = 8; i <= 248; i += 40) {
 390                 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
 391                  || i2c_smbus_read_byte_data(new_client, i + 2) != hyst
 392                  || i2c_smbus_read_byte_data(new_client, i + 3) != os)
 393                         return -ENODEV;
 394                 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
 395                                 != LM75A_ID)
 396                         return -ENODEV;
 397         }
 398
 399         strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
 400
 401         return 0;
 402 }
 403
 404 #ifdef CONFIG_PM
 405 static int lm75_suspend(struct device *dev)
 406 {
 407         int status;
 408         struct i2c_client *client = to_i2c_client(dev);
 409         status = lm75_read_value(client, LM75_REG_CONF);
 410         if (status < 0) {
 411                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 412                 return status;
 413         }
 414         status = status | LM75_SHUTDOWN;
 415         lm75_write_value(client, LM75_REG_CONF, status);
 416         return 0;
 417 }
 418
 419 static int lm75_resume(struct device *dev)
 420 {
 421         int status;
 422         struct i2c_client *client = to_i2c_client(dev);
 423         status = lm75_read_value(client, LM75_REG_CONF);
 424         if (status < 0) {
 425                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 426                 return status;
 427         }
 428         status = status & ~LM75_SHUTDOWN;
 429         lm75_write_value(client, LM75_REG_CONF, status);
 430         return 0;
 431 }
 432
 433 static const struct dev_pm_ops lm75_dev_pm_ops = {
 434         .suspend        = lm75_suspend,
 435         .resume         = lm75_resume,
 436 };
 437 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
 438 #else
 439 #define LM75_DEV_PM_OPS NULL
 440 #endif /* CONFIG_PM */
 441
 442 static struct i2c_driver lm75_driver = {
 443         .class          = I2C_CLASS_HWMON,
 444         .driver = {
 445                 .name   = "lm75",
 446                 .pm     = LM75_DEV_PM_OPS,
 447         },
 448         .probe          = lm75_probe,
 449         .remove         = lm75_remove,
 450         .id_table       = lm75_ids,
 451         .detect         = lm75_detect,
 452         .address_list   = normal_i2c,
 453 };
 454
 455 /*-----------------------------------------------------------------------*/
 456
 457 /* register access */
 458
 459 /*
 460  * All registers are word-sized, except for the configuration register.
 461  * LM75 uses a high-byte first convention, which is exactly opposite to
 462  * the SMBus standard.
 463  */
 464 static int lm75_read_value(struct i2c_client *client, u8 reg)
 465 {
 466         if (reg == LM75_REG_CONF)
 467                 return i2c_smbus_read_byte_data(client, reg);
 468         else
 469                 return i2c_smbus_read_word_swapped(client, reg);
 470 }
 471
 472 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
 473 {
 474         if (reg == LM75_REG_CONF)
 475                 return i2c_smbus_write_byte_data(client, reg, value);
 476         else
 477                 return i2c_smbus_write_word_swapped(client, reg, value);
 478 }
 479
 480 static struct lm75_data *lm75_update_device(struct device *dev)
 481 {
 482         struct i2c_client *client = to_i2c_client(dev);
 483         struct lm75_data *data = i2c_get_clientdata(client);
 484         struct lm75_data *ret = data;
 485
 486         mutex_lock(&data->update_lock);
 487
 488         if (time_after(jiffies, data->last_updated + data->sample_time)
 489             || !data->valid) {
 490                 int i;
 491                 dev_dbg(&client->dev, "Starting lm75 update\n");
 492
 493                 for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
 494                         int status;
 495
 496                         status = lm75_read_value(client, LM75_REG_TEMP[i]);
 497                         if (unlikely(status < 0)) {
 498                                 dev_dbg(dev,
 499                                         "LM75: Failed to read value: reg %d, error %d\n",
 500                                         LM75_REG_TEMP[i], status);
 501                                 ret = ERR_PTR(status);
 502                                 data->valid = 0;
 503                                 goto abort;
 504                         }
 505                         data->temp[i] = status;
 506                 }
 507                 data->last_updated = jiffies;
 508                 data->valid = 1;
 509         }
 510
 511 abort:
 512         mutex_unlock(&data->update_lock);
 513         return ret;
 514 }
 515
 516 module_i2c_driver(lm75_driver);
 517
 518 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
 519 MODULE_DESCRIPTION("LM75 driver");
 520 MODULE_LICENSE("GPL");