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 <linux/of.h>
  31 #include <linux/thermal.h>
  32 #include "lm75.h"
  33
  34
  35 /*
  36  * This driver handles the LM75 and compatible digital temperature sensors.
  37  */
  38
  39 enum lm75_type {                /* keep sorted in alphabetical order */
  40         adt75,
  41         ds1775,
  42         ds75,
  43         ds7505,
  44         g751,
  45         lm75,
  46         lm75a,
  47         max6625,
  48         max6626,
  49         mcp980x,
  50         stds75,
  51         tcn75,
  52         tmp100,
  53         tmp101,
  54         tmp105,
  55         tmp175,
  56         tmp275,
  57         tmp75,
  58 };
  59
  60 /* Addresses scanned */
  61 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  62                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  63
  64
  65 /* The LM75 registers */
  66 #define LM75_REG_CONF           0x01
  67 static const u8 LM75_REG_TEMP[3] = {
  68         0x00,           /* input */
  69         0x03,           /* max */
  70         0x02,           /* hyst */
  71 };
  72
  73 /* Each client has this additional data */
  74 struct lm75_data {
  75         struct device           *hwmon_dev;
  76         struct thermal_zone_device      *tz;
  77         struct mutex            update_lock;
  78         u8                      orig_conf;
  79         u8                      resolution;     /* In bits, between 9 and 12 */
  80         u8                      resolution_limits;
  81         char                    valid;          /* !=0 if registers are valid */
  82         unsigned long           last_updated;   /* In jiffies */
  83         unsigned long           sample_time;    /* In jiffies */
  84         s16                     temp[3];        /* Register values,
  85                                                    0 = input
  86                                                    1 = max
  87                                                    2 = hyst */
  88 };
  89
  90 static int lm75_read_value(struct i2c_client *client, u8 reg);
  91 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
  92 static struct lm75_data *lm75_update_device(struct device *dev);
  93
  94
  95 /*-----------------------------------------------------------------------*/
  96
  97 static inline long lm75_reg_to_mc(s16 temp, u8 resolution)
  98 {
  99         return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
 100 }
 101
 102 /* sysfs attributes for hwmon */
 103
 104 static int lm75_read_temp(void *dev, long *temp)
 105 {
 106         struct lm75_data *data = lm75_update_device(dev);
 107
 108         if (IS_ERR(data))
 109                 return PTR_ERR(data);
 110
 111         *temp = lm75_reg_to_mc(data->temp[0], data->resolution);
 112
 113         return 0;
 114 }
 115
 116 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
 117                          char *buf)
 118 {
 119         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 120         struct lm75_data *data = lm75_update_device(dev);
 121
 122         if (IS_ERR(data))
 123                 return PTR_ERR(data);
 124
 125         return sprintf(buf, "%ld\n", lm75_reg_to_mc(data->temp[attr->index],
 126                                                     data->resolution));
 127 }
 128
 129 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
 130                         const char *buf, size_t count)
 131 {
 132         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 133         struct i2c_client *client = to_i2c_client(dev);
 134         struct lm75_data *data = i2c_get_clientdata(client);
 135         int nr = attr->index;
 136         long temp;
 137         int error;
 138         u8 resolution;
 139
 140         error = kstrtol(buf, 10, &temp);
 141         if (error)
 142                 return error;
 143
 144         /*
 145          * Resolution of limit registers is assumed to be the same as the
 146          * temperature input register resolution unless given explicitly.
 147          */
 148         if (attr->index && data->resolution_limits)
 149                 resolution = data->resolution_limits;
 150         else
 151                 resolution = data->resolution;
 152
 153         mutex_lock(&data->update_lock);
 154         temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
 155         data->temp[nr] = DIV_ROUND_CLOSEST(temp  << (resolution - 8),
 156                                            1000) << (16 - resolution);
 157         lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
 158         mutex_unlock(&data->update_lock);
 159         return count;
 160 }
 161
 162 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 163                         show_temp, set_temp, 1);
 164 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
 165                         show_temp, set_temp, 2);
 166 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 167
 168 static struct attribute *lm75_attributes[] = {
 169         &sensor_dev_attr_temp1_input.dev_attr.attr,
 170         &sensor_dev_attr_temp1_max.dev_attr.attr,
 171         &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 172
 173         NULL
 174 };
 175
 176 static const struct attribute_group lm75_group = {
 177         .attrs = lm75_attributes,
 178 };
 179
 180 /*-----------------------------------------------------------------------*/
 181
 182 /* device probe and removal */
 183
 184 static int
 185 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 186 {
 187         struct lm75_data *data;
 188         int status;
 189         u8 set_mask, clr_mask;
 190         int new;
 191         enum lm75_type kind = id->driver_data;
 192
 193         if (!i2c_check_functionality(client->adapter,
 194                         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
 195                 return -EIO;
 196
 197         data = devm_kzalloc(&client->dev, sizeof(struct lm75_data), GFP_KERNEL);
 198         if (!data)
 199                 return -ENOMEM;
 200
 201         i2c_set_clientdata(client, data);
 202         mutex_init(&data->update_lock);
 203
 204         /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
 205          * Then tweak to be more precise when appropriate.
 206          */
 207         set_mask = 0;
 208         clr_mask = LM75_SHUTDOWN;               /* continuous conversions */
 209
 210         switch (kind) {
 211         case adt75:
 212                 clr_mask |= 1 << 5;             /* not one-shot mode */
 213                 data->resolution = 12;
 214                 data->sample_time = HZ / 8;
 215                 break;
 216         case ds1775:
 217         case ds75:
 218         case stds75:
 219                 clr_mask |= 3 << 5;
 220                 set_mask |= 2 << 5;             /* 11-bit mode */
 221                 data->resolution = 11;
 222                 data->sample_time = HZ;
 223                 break;
 224         case ds7505:
 225                 set_mask |= 3 << 5;             /* 12-bit mode */
 226                 data->resolution = 12;
 227                 data->sample_time = HZ / 4;
 228                 break;
 229         case g751:
 230         case lm75:
 231         case lm75a:
 232                 data->resolution = 9;
 233                 data->sample_time = HZ / 2;
 234                 break;
 235         case max6625:
 236                 data->resolution = 9;
 237                 data->sample_time = HZ / 4;
 238                 break;
 239         case max6626:
 240                 data->resolution = 12;
 241                 data->resolution_limits = 9;
 242                 data->sample_time = HZ / 4;
 243                 break;
 244         case tcn75:
 245                 data->resolution = 9;
 246                 data->sample_time = HZ / 8;
 247                 break;
 248         case mcp980x:
 249                 data->resolution_limits = 9;
 250                 /* fall through */
 251         case tmp100:
 252         case tmp101:
 253                 set_mask |= 3 << 5;             /* 12-bit mode */
 254                 data->resolution = 12;
 255                 data->sample_time = HZ;
 256                 clr_mask |= 1 << 7;             /* not one-shot mode */
 257                 break;
 258         case tmp105:
 259         case tmp175:
 260         case tmp275:
 261         case tmp75:
 262                 set_mask |= 3 << 5;             /* 12-bit mode */
 263                 clr_mask |= 1 << 7;             /* not one-shot mode */
 264                 data->resolution = 12;
 265                 data->sample_time = HZ / 2;
 266                 break;
 267         }
 268
 269         /* configure as specified */
 270         status = lm75_read_value(client, LM75_REG_CONF);
 271         if (status < 0) {
 272                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 273                 return status;
 274         }
 275         data->orig_conf = status;
 276         new = status & ~clr_mask;
 277         new |= set_mask;
 278         if (status != new)
 279                 lm75_write_value(client, LM75_REG_CONF, new);
 280         dev_dbg(&client->dev, "Config %02x\n", new);
 281
 282         /* Register sysfs hooks */
 283         status = sysfs_create_group(&client->dev.kobj, &lm75_group);
 284         if (status)
 285                 return status;
 286
 287         data->hwmon_dev = hwmon_device_register(&client->dev);
 288         if (IS_ERR(data->hwmon_dev)) {
 289                 status = PTR_ERR(data->hwmon_dev);
 290                 goto exit_remove;
 291         }
 292
 293         data->tz = thermal_zone_of_sensor_register(&client->dev,
 294                                                    0,
 295                                                    &client->dev,
 296                                                    lm75_read_temp, NULL);
 297         if (IS_ERR(data->tz))
 298                 data->tz = NULL;
 299
 300         dev_info(&client->dev, "%s: sensor '%s'\n",
 301                  dev_name(data->hwmon_dev), client->name);
 302
 303         return 0;
 304
 305 exit_remove:
 306         sysfs_remove_group(&client->dev.kobj, &lm75_group);
 307         return status;
 308 }
 309
 310 static int lm75_remove(struct i2c_client *client)
 311 {
 312         struct lm75_data *data = i2c_get_clientdata(client);
 313
 314         thermal_zone_of_sensor_unregister(&client->dev, data->tz);
 315         hwmon_device_unregister(data->hwmon_dev);
 316         sysfs_remove_group(&client->dev.kobj, &lm75_group);
 317         lm75_write_value(client, LM75_REG_CONF, data->orig_conf);
 318         return 0;
 319 }
 320
 321 static const struct i2c_device_id lm75_ids[] = {
 322         { "adt75", adt75, },
 323         { "ds1775", ds1775, },
 324         { "ds75", ds75, },
 325         { "ds7505", ds7505, },
 326         { "g751", g751, },
 327         { "lm75", lm75, },
 328         { "lm75a", lm75a, },
 329         { "max6625", max6625, },
 330         { "max6626", max6626, },
 331         { "mcp980x", mcp980x, },
 332         { "stds75", stds75, },
 333         { "tcn75", tcn75, },
 334         { "tmp100", tmp100, },
 335         { "tmp101", tmp101, },
 336         { "tmp105", tmp105, },
 337         { "tmp175", tmp175, },
 338         { "tmp275", tmp275, },
 339         { "tmp75", tmp75, },
 340         { /* LIST END */ }
 341 };
 342 MODULE_DEVICE_TABLE(i2c, lm75_ids);
 343
 344 #define LM75A_ID 0xA1
 345
 346 /* Return 0 if detection is successful, -ENODEV otherwise */
 347 static int lm75_detect(struct i2c_client *new_client,
 348                        struct i2c_board_info *info)
 349 {
 350         struct i2c_adapter *adapter = new_client->adapter;
 351         int i;
 352         int conf, hyst, os;
 353         bool is_lm75a = 0;
 354
 355         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 356                                      I2C_FUNC_SMBUS_WORD_DATA))
 357                 return -ENODEV;
 358
 359         /*
 360          * Now, we do the remaining detection. There is no identification-
 361          * dedicated register so we have to rely on several tricks:
 362          * unused bits, registers cycling over 8-address boundaries,
 363          * addresses 0x04-0x07 returning the last read value.
 364          * The cycling+unused addresses combination is not tested,
 365          * since it would significantly slow the detection down and would
 366          * hardly add any value.
 367          *
 368          * The National Semiconductor LM75A is different than earlier
 369          * LM75s.  It has an ID byte of 0xaX (where X is the chip
 370          * revision, with 1 being the only revision in existence) in
 371          * register 7, and unused registers return 0xff rather than the
 372          * last read value.
 373          *
 374          * Note that this function only detects the original National
 375          * Semiconductor LM75 and the LM75A. Clones from other vendors
 376          * aren't detected, on purpose, because they are typically never
 377          * found on PC hardware. They are found on embedded designs where
 378          * they can be instantiated explicitly so detection is not needed.
 379          * The absence of identification registers on all these clones
 380          * would make their exhaustive detection very difficult and weak,
 381          * and odds are that the driver would bind to unsupported devices.
 382          */
 383
 384         /* Unused bits */
 385         conf = i2c_smbus_read_byte_data(new_client, 1);
 386         if (conf & 0xe0)
 387                 return -ENODEV;
 388
 389         /* First check for LM75A */
 390         if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
 391                 /* LM75A returns 0xff on unused registers so
 392                    just to be sure we check for that too. */
 393                 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
 394                  || i2c_smbus_read_byte_data(new_client, 5) != 0xff
 395                  || i2c_smbus_read_byte_data(new_client, 6) != 0xff)
 396                         return -ENODEV;
 397                 is_lm75a = 1;
 398                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 399                 os = i2c_smbus_read_byte_data(new_client, 3);
 400         } else { /* Traditional style LM75 detection */
 401                 /* Unused addresses */
 402                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 403                 if (i2c_smbus_read_byte_data(new_client, 4) != hyst
 404                  || i2c_smbus_read_byte_data(new_client, 5) != hyst
 405                  || i2c_smbus_read_byte_data(new_client, 6) != hyst
 406                  || i2c_smbus_read_byte_data(new_client, 7) != hyst)
 407                         return -ENODEV;
 408                 os = i2c_smbus_read_byte_data(new_client, 3);
 409                 if (i2c_smbus_read_byte_data(new_client, 4) != os
 410                  || i2c_smbus_read_byte_data(new_client, 5) != os
 411                  || i2c_smbus_read_byte_data(new_client, 6) != os
 412                  || i2c_smbus_read_byte_data(new_client, 7) != os)
 413                         return -ENODEV;
 414         }
 415
 416         /* Addresses cycling */
 417         for (i = 8; i <= 248; i += 40) {
 418                 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
 419                  || i2c_smbus_read_byte_data(new_client, i + 2) != hyst
 420                  || i2c_smbus_read_byte_data(new_client, i + 3) != os)
 421                         return -ENODEV;
 422                 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
 423                                 != LM75A_ID)
 424                         return -ENODEV;
 425         }
 426
 427         strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
 428
 429         return 0;
 430 }
 431
 432 #ifdef CONFIG_PM
 433 static int lm75_suspend(struct device *dev)
 434 {
 435         int status;
 436         struct i2c_client *client = to_i2c_client(dev);
 437         status = lm75_read_value(client, LM75_REG_CONF);
 438         if (status < 0) {
 439                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 440                 return status;
 441         }
 442         status = status | LM75_SHUTDOWN;
 443         lm75_write_value(client, LM75_REG_CONF, status);
 444         return 0;
 445 }
 446
 447 static int lm75_resume(struct device *dev)
 448 {
 449         int status;
 450         struct i2c_client *client = to_i2c_client(dev);
 451         status = lm75_read_value(client, LM75_REG_CONF);
 452         if (status < 0) {
 453                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 454                 return status;
 455         }
 456         status = status & ~LM75_SHUTDOWN;
 457         lm75_write_value(client, LM75_REG_CONF, status);
 458         return 0;
 459 }
 460
 461 static const struct dev_pm_ops lm75_dev_pm_ops = {
 462         .suspend        = lm75_suspend,
 463         .resume         = lm75_resume,
 464 };
 465 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
 466 #else
 467 #define LM75_DEV_PM_OPS NULL
 468 #endif /* CONFIG_PM */
 469
 470 static struct i2c_driver lm75_driver = {
 471         .class          = I2C_CLASS_HWMON,
 472         .driver = {
 473                 .name   = "lm75",
 474                 .pm     = LM75_DEV_PM_OPS,
 475         },
 476         .probe          = lm75_probe,
 477         .remove         = lm75_remove,
 478         .id_table       = lm75_ids,
 479         .detect         = lm75_detect,
 480         .address_list   = normal_i2c,
 481 };
 482
 483 /*-----------------------------------------------------------------------*/
 484
 485 /* register access */
 486
 487 /*
 488  * All registers are word-sized, except for the configuration register.
 489  * LM75 uses a high-byte first convention, which is exactly opposite to
 490  * the SMBus standard.
 491  */
 492 static int lm75_read_value(struct i2c_client *client, u8 reg)
 493 {
 494         if (reg == LM75_REG_CONF)
 495                 return i2c_smbus_read_byte_data(client, reg);
 496         else
 497                 return i2c_smbus_read_word_swapped(client, reg);
 498 }
 499
 500 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
 501 {
 502         if (reg == LM75_REG_CONF)
 503                 return i2c_smbus_write_byte_data(client, reg, value);
 504         else
 505                 return i2c_smbus_write_word_swapped(client, reg, value);
 506 }
 507
 508 static struct lm75_data *lm75_update_device(struct device *dev)
 509 {
 510         struct i2c_client *client = to_i2c_client(dev);
 511         struct lm75_data *data = i2c_get_clientdata(client);
 512         struct lm75_data *ret = data;
 513
 514         mutex_lock(&data->update_lock);
 515
 516         if (time_after(jiffies, data->last_updated + data->sample_time)
 517             || !data->valid) {
 518                 int i;
 519                 dev_dbg(&client->dev, "Starting lm75 update\n");
 520
 521                 for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
 522                         int status;
 523
 524                         status = lm75_read_value(client, LM75_REG_TEMP[i]);
 525                         if (unlikely(status < 0)) {
 526                                 dev_dbg(dev,
 527                                         "LM75: Failed to read value: reg %d, error %d\n",
 528                                         LM75_REG_TEMP[i], status);
 529                                 ret = ERR_PTR(status);
 530                                 data->valid = 0;
 531                                 goto abort;
 532                         }
 533                         data->temp[i] = status;
 534                 }
 535                 data->last_updated = jiffies;
 536                 data->valid = 1;
 537         }
 538
 539 abort:
 540         mutex_unlock(&data->update_lock);
 541         return ret;
 542 }
 543
 544 module_i2c_driver(lm75_driver);
 545
 546 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
 547 MODULE_DESCRIPTION("LM75 driver");
 548 MODULE_LICENSE("GPL");