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         lm75b,
  48         max6625,
  49         max6626,
  50         mcp980x,
  51         stds75,
  52         tcn75,
  53         tmp100,
  54         tmp101,
  55         tmp105,
  56         tmp112,
  57         tmp175,
  58         tmp275,
  59         tmp75,
  60         tmp75c,
  61 };
  62
  63 /* Addresses scanned */
  64 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  65                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  66
  67
  68 /* The LM75 registers */
  69 #define LM75_REG_CONF           0x01
  70 static const u8 LM75_REG_TEMP[3] = {
  71         0x00,           /* input */
  72         0x03,           /* max */
  73         0x02,           /* hyst */
  74 };
  75
  76 /* Each client has this additional data */
  77 struct lm75_data {
  78         struct i2c_client       *client;
  79         struct device           *hwmon_dev;
  80         struct thermal_zone_device      *tz;
  81         struct mutex            update_lock;
  82         u8                      orig_conf;
  83         u8                      resolution;     /* In bits, between 9 and 12 */
  84         u8                      resolution_limits;
  85         char                    valid;          /* !=0 if registers are valid */
  86         unsigned long           last_updated;   /* In jiffies */
  87         unsigned long           sample_time;    /* In jiffies */
  88         s16                     temp[3];        /* Register values,
  89                                                    0 = input
  90                                                    1 = max
  91                                                    2 = hyst */
  92 };
  93
  94 static int lm75_read_value(struct i2c_client *client, u8 reg);
  95 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
  96 static struct lm75_data *lm75_update_device(struct device *dev);
  97
  98
  99 /*-----------------------------------------------------------------------*/
 100
 101 static inline long lm75_reg_to_mc(s16 temp, u8 resolution)
 102 {
 103         return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
 104 }
 105
 106 /* sysfs attributes for hwmon */
 107
 108 static int lm75_read_temp(void *dev, int *temp)
 109 {
 110         struct lm75_data *data = lm75_update_device(dev);
 111
 112         if (IS_ERR(data))
 113                 return PTR_ERR(data);
 114
 115         *temp = lm75_reg_to_mc(data->temp[0], data->resolution);
 116
 117         return 0;
 118 }
 119
 120 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
 121                          char *buf)
 122 {
 123         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 124         struct lm75_data *data = lm75_update_device(dev);
 125
 126         if (IS_ERR(data))
 127                 return PTR_ERR(data);
 128
 129         return sprintf(buf, "%ld\n", lm75_reg_to_mc(data->temp[attr->index],
 130                                                     data->resolution));
 131 }
 132
 133 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
 134                         const char *buf, size_t count)
 135 {
 136         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 137         struct lm75_data *data = dev_get_drvdata(dev);
 138         struct i2c_client *client = data->client;
 139         int nr = attr->index;
 140         long temp;
 141         int error;
 142         u8 resolution;
 143
 144         error = kstrtol(buf, 10, &temp);
 145         if (error)
 146                 return error;
 147
 148         /*
 149          * Resolution of limit registers is assumed to be the same as the
 150          * temperature input register resolution unless given explicitly.
 151          */
 152         if (attr->index && data->resolution_limits)
 153                 resolution = data->resolution_limits;
 154         else
 155                 resolution = data->resolution;
 156
 157         mutex_lock(&data->update_lock);
 158         temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
 159         data->temp[nr] = DIV_ROUND_CLOSEST(temp  << (resolution - 8),
 160                                            1000) << (16 - resolution);
 161         lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
 162         mutex_unlock(&data->update_lock);
 163         return count;
 164 }
 165
 166 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 167                         show_temp, set_temp, 1);
 168 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
 169                         show_temp, set_temp, 2);
 170 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 171
 172 static struct attribute *lm75_attrs[] = {
 173         &sensor_dev_attr_temp1_input.dev_attr.attr,
 174         &sensor_dev_attr_temp1_max.dev_attr.attr,
 175         &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 176
 177         NULL
 178 };
 179 ATTRIBUTE_GROUPS(lm75);
 180
 181 static const struct thermal_zone_of_device_ops lm75_of_thermal_ops = {
 182         .get_temp = lm75_read_temp,
 183 };
 184
 185 /*-----------------------------------------------------------------------*/
 186
 187 /* device probe and removal */
 188
 189 static int
 190 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 191 {
 192         struct device *dev = &client->dev;
 193         struct lm75_data *data;
 194         int status;
 195         u8 set_mask, clr_mask;
 196         int new;
 197         enum lm75_type kind = id->driver_data;
 198
 199         if (!i2c_check_functionality(client->adapter,
 200                         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
 201                 return -EIO;
 202
 203         data = devm_kzalloc(dev, sizeof(struct lm75_data), GFP_KERNEL);
 204         if (!data)
 205                 return -ENOMEM;
 206
 207         data->client = client;
 208         i2c_set_clientdata(client, data);
 209         mutex_init(&data->update_lock);
 210
 211         /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
 212          * Then tweak to be more precise when appropriate.
 213          */
 214         set_mask = 0;
 215         clr_mask = LM75_SHUTDOWN;               /* continuous conversions */
 216
 217         switch (kind) {
 218         case adt75:
 219                 clr_mask |= 1 << 5;             /* not one-shot mode */
 220                 data->resolution = 12;
 221                 data->sample_time = HZ / 8;
 222                 break;
 223         case ds1775:
 224         case ds75:
 225         case stds75:
 226                 clr_mask |= 3 << 5;
 227                 set_mask |= 2 << 5;             /* 11-bit mode */
 228                 data->resolution = 11;
 229                 data->sample_time = HZ;
 230                 break;
 231         case ds7505:
 232                 set_mask |= 3 << 5;             /* 12-bit mode */
 233                 data->resolution = 12;
 234                 data->sample_time = HZ / 4;
 235                 break;
 236         case g751:
 237         case lm75:
 238         case lm75a:
 239                 data->resolution = 9;
 240                 data->sample_time = HZ / 2;
 241                 break;
 242         case lm75b:
 243                 data->resolution = 11;
 244                 data->sample_time = HZ / 4;
 245                 break;
 246         case max6625:
 247                 data->resolution = 9;
 248                 data->sample_time = HZ / 4;
 249                 break;
 250         case max6626:
 251                 data->resolution = 12;
 252                 data->resolution_limits = 9;
 253                 data->sample_time = HZ / 4;
 254                 break;
 255         case tcn75:
 256                 data->resolution = 9;
 257                 data->sample_time = HZ / 8;
 258                 break;
 259         case mcp980x:
 260                 data->resolution_limits = 9;
 261                 /* fall through */
 262         case tmp100:
 263         case tmp101:
 264                 set_mask |= 3 << 5;             /* 12-bit mode */
 265                 data->resolution = 12;
 266                 data->sample_time = HZ;
 267                 clr_mask |= 1 << 7;             /* not one-shot mode */
 268                 break;
 269         case tmp112:
 270                 set_mask |= 3 << 5;             /* 12-bit mode */
 271                 clr_mask |= 1 << 7;             /* not one-shot mode */
 272                 data->resolution = 12;
 273                 data->sample_time = HZ / 4;
 274                 break;
 275         case tmp105:
 276         case tmp175:
 277         case tmp275:
 278         case tmp75:
 279                 set_mask |= 3 << 5;             /* 12-bit mode */
 280                 clr_mask |= 1 << 7;             /* not one-shot mode */
 281                 data->resolution = 12;
 282                 data->sample_time = HZ / 2;
 283                 break;
 284         case tmp75c:
 285                 clr_mask |= 1 << 5;             /* not one-shot mode */
 286                 data->resolution = 12;
 287                 data->sample_time = HZ / 4;
 288                 break;
 289         }
 290
 291         /* configure as specified */
 292         status = lm75_read_value(client, LM75_REG_CONF);
 293         if (status < 0) {
 294                 dev_dbg(dev, "Can't read config? %d\n", status);
 295                 return status;
 296         }
 297         data->orig_conf = status;
 298         new = status & ~clr_mask;
 299         new |= set_mask;
 300         if (status != new)
 301                 lm75_write_value(client, LM75_REG_CONF, new);
 302         dev_dbg(dev, "Config %02x\n", new);
 303
 304         data->hwmon_dev = hwmon_device_register_with_groups(dev, client->name,
 305                                                             data, lm75_groups);
 306         if (IS_ERR(data->hwmon_dev))
 307                 return PTR_ERR(data->hwmon_dev);
 308
 309         data->tz = thermal_zone_of_sensor_register(data->hwmon_dev, 0,
 310                                                    data->hwmon_dev,
 311                                                    &lm75_of_thermal_ops);
 312         if (IS_ERR(data->tz))
 313                 data->tz = NULL;
 314
 315         dev_info(dev, "%s: sensor '%s'\n",
 316                  dev_name(data->hwmon_dev), client->name);
 317
 318         return 0;
 319 }
 320
 321 static int lm75_remove(struct i2c_client *client)
 322 {
 323         struct lm75_data *data = i2c_get_clientdata(client);
 324
 325         thermal_zone_of_sensor_unregister(data->hwmon_dev, data->tz);
 326         hwmon_device_unregister(data->hwmon_dev);
 327         lm75_write_value(client, LM75_REG_CONF, data->orig_conf);
 328         return 0;
 329 }
 330
 331 static const struct i2c_device_id lm75_ids[] = {
 332         { "adt75", adt75, },
 333         { "ds1775", ds1775, },
 334         { "ds75", ds75, },
 335         { "ds7505", ds7505, },
 336         { "g751", g751, },
 337         { "lm75", lm75, },
 338         { "lm75a", lm75a, },
 339         { "lm75b", lm75b, },
 340         { "max6625", max6625, },
 341         { "max6626", max6626, },
 342         { "mcp980x", mcp980x, },
 343         { "stds75", stds75, },
 344         { "tcn75", tcn75, },
 345         { "tmp100", tmp100, },
 346         { "tmp101", tmp101, },
 347         { "tmp105", tmp105, },
 348         { "tmp112", tmp112, },
 349         { "tmp175", tmp175, },
 350         { "tmp275", tmp275, },
 351         { "tmp75", tmp75, },
 352         { "tmp75c", tmp75c, },
 353         { /* LIST END */ }
 354 };
 355 MODULE_DEVICE_TABLE(i2c, lm75_ids);
 356
 357 #define LM75A_ID 0xA1
 358
 359 /* Return 0 if detection is successful, -ENODEV otherwise */
 360 static int lm75_detect(struct i2c_client *new_client,
 361                        struct i2c_board_info *info)
 362 {
 363         struct i2c_adapter *adapter = new_client->adapter;
 364         int i;
 365         int conf, hyst, os;
 366         bool is_lm75a = 0;
 367
 368         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 369                                      I2C_FUNC_SMBUS_WORD_DATA))
 370                 return -ENODEV;
 371
 372         /*
 373          * Now, we do the remaining detection. There is no identification-
 374          * dedicated register so we have to rely on several tricks:
 375          * unused bits, registers cycling over 8-address boundaries,
 376          * addresses 0x04-0x07 returning the last read value.
 377          * The cycling+unused addresses combination is not tested,
 378          * since it would significantly slow the detection down and would
 379          * hardly add any value.
 380          *
 381          * The National Semiconductor LM75A is different than earlier
 382          * LM75s.  It has an ID byte of 0xaX (where X is the chip
 383          * revision, with 1 being the only revision in existence) in
 384          * register 7, and unused registers return 0xff rather than the
 385          * last read value.
 386          *
 387          * Note that this function only detects the original National
 388          * Semiconductor LM75 and the LM75A. Clones from other vendors
 389          * aren't detected, on purpose, because they are typically never
 390          * found on PC hardware. They are found on embedded designs where
 391          * they can be instantiated explicitly so detection is not needed.
 392          * The absence of identification registers on all these clones
 393          * would make their exhaustive detection very difficult and weak,
 394          * and odds are that the driver would bind to unsupported devices.
 395          */
 396
 397         /* Unused bits */
 398         conf = i2c_smbus_read_byte_data(new_client, 1);
 399         if (conf & 0xe0)
 400                 return -ENODEV;
 401
 402         /* First check for LM75A */
 403         if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
 404                 /* LM75A returns 0xff on unused registers so
 405                    just to be sure we check for that too. */
 406                 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
 407                  || i2c_smbus_read_byte_data(new_client, 5) != 0xff
 408                  || i2c_smbus_read_byte_data(new_client, 6) != 0xff)
 409                         return -ENODEV;
 410                 is_lm75a = 1;
 411                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 412                 os = i2c_smbus_read_byte_data(new_client, 3);
 413         } else { /* Traditional style LM75 detection */
 414                 /* Unused addresses */
 415                 hyst = i2c_smbus_read_byte_data(new_client, 2);
 416                 if (i2c_smbus_read_byte_data(new_client, 4) != hyst
 417                  || i2c_smbus_read_byte_data(new_client, 5) != hyst
 418                  || i2c_smbus_read_byte_data(new_client, 6) != hyst
 419                  || i2c_smbus_read_byte_data(new_client, 7) != hyst)
 420                         return -ENODEV;
 421                 os = i2c_smbus_read_byte_data(new_client, 3);
 422                 if (i2c_smbus_read_byte_data(new_client, 4) != os
 423                  || i2c_smbus_read_byte_data(new_client, 5) != os
 424                  || i2c_smbus_read_byte_data(new_client, 6) != os
 425                  || i2c_smbus_read_byte_data(new_client, 7) != os)
 426                         return -ENODEV;
 427         }
 428         /*
 429          * It is very unlikely that this is a LM75 if both
 430          * hysteresis and temperature limit registers are 0.
 431          */
 432         if (hyst == 0 && os == 0)
 433                 return -ENODEV;
 434
 435         /* Addresses cycling */
 436         for (i = 8; i <= 248; i += 40) {
 437                 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
 438                  || i2c_smbus_read_byte_data(new_client, i + 2) != hyst
 439                  || i2c_smbus_read_byte_data(new_client, i + 3) != os)
 440                         return -ENODEV;
 441                 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
 442                                 != LM75A_ID)
 443                         return -ENODEV;
 444         }
 445
 446         strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
 447
 448         return 0;
 449 }
 450
 451 #ifdef CONFIG_PM
 452 static int lm75_suspend(struct device *dev)
 453 {
 454         int status;
 455         struct i2c_client *client = to_i2c_client(dev);
 456         status = lm75_read_value(client, LM75_REG_CONF);
 457         if (status < 0) {
 458                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 459                 return status;
 460         }
 461         status = status | LM75_SHUTDOWN;
 462         lm75_write_value(client, LM75_REG_CONF, status);
 463         return 0;
 464 }
 465
 466 static int lm75_resume(struct device *dev)
 467 {
 468         int status;
 469         struct i2c_client *client = to_i2c_client(dev);
 470         status = lm75_read_value(client, LM75_REG_CONF);
 471         if (status < 0) {
 472                 dev_dbg(&client->dev, "Can't read config? %d\n", status);
 473                 return status;
 474         }
 475         status = status & ~LM75_SHUTDOWN;
 476         lm75_write_value(client, LM75_REG_CONF, status);
 477         return 0;
 478 }
 479
 480 static const struct dev_pm_ops lm75_dev_pm_ops = {
 481         .suspend        = lm75_suspend,
 482         .resume         = lm75_resume,
 483 };
 484 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
 485 #else
 486 #define LM75_DEV_PM_OPS NULL
 487 #endif /* CONFIG_PM */
 488
 489 static struct i2c_driver lm75_driver = {
 490         .class          = I2C_CLASS_HWMON,
 491         .driver = {
 492                 .name   = "lm75",
 493                 .pm     = LM75_DEV_PM_OPS,
 494         },
 495         .probe          = lm75_probe,
 496         .remove         = lm75_remove,
 497         .id_table       = lm75_ids,
 498         .detect         = lm75_detect,
 499         .address_list   = normal_i2c,
 500 };
 501
 502 /*-----------------------------------------------------------------------*/
 503
 504 /* register access */
 505
 506 /*
 507  * All registers are word-sized, except for the configuration register.
 508  * LM75 uses a high-byte first convention, which is exactly opposite to
 509  * the SMBus standard.
 510  */
 511 static int lm75_read_value(struct i2c_client *client, u8 reg)
 512 {
 513         if (reg == LM75_REG_CONF)
 514                 return i2c_smbus_read_byte_data(client, reg);
 515         else
 516                 return i2c_smbus_read_word_swapped(client, reg);
 517 }
 518
 519 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
 520 {
 521         if (reg == LM75_REG_CONF)
 522                 return i2c_smbus_write_byte_data(client, reg, value);
 523         else
 524                 return i2c_smbus_write_word_swapped(client, reg, value);
 525 }
 526
 527 static struct lm75_data *lm75_update_device(struct device *dev)
 528 {
 529         struct lm75_data *data = dev_get_drvdata(dev);
 530         struct i2c_client *client = data->client;
 531         struct lm75_data *ret = data;
 532
 533         mutex_lock(&data->update_lock);
 534
 535         if (time_after(jiffies, data->last_updated + data->sample_time)
 536             || !data->valid) {
 537                 int i;
 538                 dev_dbg(&client->dev, "Starting lm75 update\n");
 539
 540                 for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
 541                         int status;
 542
 543                         status = lm75_read_value(client, LM75_REG_TEMP[i]);
 544                         if (unlikely(status < 0)) {
 545                                 dev_dbg(dev,
 546                                         "LM75: Failed to read value: reg %d, error %d\n",
 547                                         LM75_REG_TEMP[i], status);
 548                                 ret = ERR_PTR(status);
 549                                 data->valid = 0;
 550                                 goto abort;
 551                         }
 552                         data->temp[i] = status;
 553                 }
 554                 data->last_updated = jiffies;
 555                 data->valid = 1;
 556         }
 557
 558 abort:
 559         mutex_unlock(&data->update_lock);
 560         return ret;
 561 }
 562
 563 module_i2c_driver(lm75_driver);
 564
 565 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
 566 MODULE_DESCRIPTION("LM75 driver");
 567 MODULE_LICENSE("GPL");