root/drivers/hwmon/sht3x.c

DEFINITIONS

1. get_mode_from_update_interval
2. sht3x_read_from_command
3. sht3x_extract_temperature
4. sht3x_extract_humidity
5. sht3x_update_client
6. temp1_input_show
7. humidity1_input_show
8. limits_update
9. temp1_limit_show
10. humidity1_limit_show
11. limit_store
12. temp1_limit_store
13. humidity1_limit_store
14. sht3x_select_command
15. status_register_read
16. temp1_alarm_show
17. humidity1_alarm_show
18. heater_enable_show
19. heater_enable_store
20. update_interval_show
21. update_interval_store
22. sht3x_probe

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* Sensirion SHT3x-DIS humidity and temperature sensor driver.
   3  * The SHT3x comes in many different versions, this driver is for the
   4  * I2C version only.
   5  *
   6  * Copyright (C) 2016 Sensirion AG, Switzerland
   7  * Author: David Frey <david.frey@sensirion.com>
   8  * Author: Pascal Sachs <pascal.sachs@sensirion.com>
   9  */
  10 
  11 #include <asm/page.h>
  12 #include <linux/crc8.h>
  13 #include <linux/delay.h>
  14 #include <linux/err.h>
  15 #include <linux/hwmon.h>
  16 #include <linux/hwmon-sysfs.h>
  17 #include <linux/i2c.h>
  18 #include <linux/init.h>
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/slab.h>
  22 #include <linux/jiffies.h>
  23 #include <linux/platform_data/sht3x.h>
  24 
  25 /* commands (high precision mode) */
  26 static const unsigned char sht3x_cmd_measure_blocking_hpm[]    = { 0x2c, 0x06 };
  27 static const unsigned char sht3x_cmd_measure_nonblocking_hpm[] = { 0x24, 0x00 };
  28 
  29 /* commands (low power mode) */
  30 static const unsigned char sht3x_cmd_measure_blocking_lpm[]    = { 0x2c, 0x10 };
  31 static const unsigned char sht3x_cmd_measure_nonblocking_lpm[] = { 0x24, 0x16 };
  32 
  33 /* commands for periodic mode */
  34 static const unsigned char sht3x_cmd_measure_periodic_mode[]   = { 0xe0, 0x00 };
  35 static const unsigned char sht3x_cmd_break[]                   = { 0x30, 0x93 };
  36 
  37 /* commands for heater control */
  38 static const unsigned char sht3x_cmd_heater_on[]               = { 0x30, 0x6d };
  39 static const unsigned char sht3x_cmd_heater_off[]              = { 0x30, 0x66 };
  40 
  41 /* other commands */
  42 static const unsigned char sht3x_cmd_read_status_reg[]         = { 0xf3, 0x2d };
  43 static const unsigned char sht3x_cmd_clear_status_reg[]        = { 0x30, 0x41 };
  44 
  45 /* delays for non-blocking i2c commands, both in us */
  46 #define SHT3X_NONBLOCKING_WAIT_TIME_HPM  15000
  47 #define SHT3X_NONBLOCKING_WAIT_TIME_LPM   4000
  48 
  49 #define SHT3X_WORD_LEN         2
  50 #define SHT3X_CMD_LENGTH       2
  51 #define SHT3X_CRC8_LEN         1
  52 #define SHT3X_RESPONSE_LENGTH  6
  53 #define SHT3X_CRC8_POLYNOMIAL  0x31
  54 #define SHT3X_CRC8_INIT        0xFF
  55 #define SHT3X_MIN_TEMPERATURE  -45000
  56 #define SHT3X_MAX_TEMPERATURE  130000
  57 #define SHT3X_MIN_HUMIDITY     0
  58 #define SHT3X_MAX_HUMIDITY     100000
  59 
  60 enum sht3x_chips {
  61         sht3x,
  62         sts3x,
  63 };
  64 
  65 enum sht3x_limits {
  66         limit_max = 0,
  67         limit_max_hyst,
  68         limit_min,
  69         limit_min_hyst,
  70 };
  71 
  72 DECLARE_CRC8_TABLE(sht3x_crc8_table);
  73 
  74 /* periodic measure commands (high precision mode) */
  75 static const char periodic_measure_commands_hpm[][SHT3X_CMD_LENGTH] = {
  76         /* 0.5 measurements per second */
  77         {0x20, 0x32},
  78         /* 1 measurements per second */
  79         {0x21, 0x30},
  80         /* 2 measurements per second */
  81         {0x22, 0x36},
  82         /* 4 measurements per second */
  83         {0x23, 0x34},
  84         /* 10 measurements per second */
  85         {0x27, 0x37},
  86 };
  87 
  88 /* periodic measure commands (low power mode) */
  89 static const char periodic_measure_commands_lpm[][SHT3X_CMD_LENGTH] = {
  90         /* 0.5 measurements per second */
  91         {0x20, 0x2f},
  92         /* 1 measurements per second */
  93         {0x21, 0x2d},
  94         /* 2 measurements per second */
  95         {0x22, 0x2b},
  96         /* 4 measurements per second */
  97         {0x23, 0x29},
  98         /* 10 measurements per second */
  99         {0x27, 0x2a},
 100 };
 101 
 102 struct sht3x_limit_commands {
 103         const char read_command[SHT3X_CMD_LENGTH];
 104         const char write_command[SHT3X_CMD_LENGTH];
 105 };
 106 
 107 static const struct sht3x_limit_commands limit_commands[] = {
 108         /* temp1_max, humidity1_max */
 109         [limit_max] = { {0xe1, 0x1f}, {0x61, 0x1d} },
 110         /* temp_1_max_hyst, humidity1_max_hyst */
 111         [limit_max_hyst] = { {0xe1, 0x14}, {0x61, 0x16} },
 112         /* temp1_min, humidity1_min */
 113         [limit_min] = { {0xe1, 0x02}, {0x61, 0x00} },
 114         /* temp_1_min_hyst, humidity1_min_hyst */
 115         [limit_min_hyst] = { {0xe1, 0x09}, {0x61, 0x0B} },
 116 };
 117 
 118 #define SHT3X_NUM_LIMIT_CMD  ARRAY_SIZE(limit_commands)
 119 
 120 static const u16 mode_to_update_interval[] = {
 121            0,
 122         2000,
 123         1000,
 124          500,
 125          250,
 126          100,
 127 };
 128 
 129 struct sht3x_data {
 130         struct i2c_client *client;
 131         struct mutex i2c_lock; /* lock for sending i2c commands */
 132         struct mutex data_lock; /* lock for updating driver data */
 133 
 134         u8 mode;
 135         const unsigned char *command;
 136         u32 wait_time;                  /* in us*/
 137         unsigned long last_update;      /* last update in periodic mode*/
 138 
 139         struct sht3x_platform_data setup;
 140 
 141         /*
 142          * cached values for temperature and humidity and limits
 143          * the limits arrays have the following order:
 144          * max, max_hyst, min, min_hyst
 145          */
 146         int temperature;
 147         int temperature_limits[SHT3X_NUM_LIMIT_CMD];
 148         u32 humidity;
 149         u32 humidity_limits[SHT3X_NUM_LIMIT_CMD];
 150 };
 151 
 152 static u8 get_mode_from_update_interval(u16 value)
 153 {
 154         size_t index;
 155         u8 number_of_modes = ARRAY_SIZE(mode_to_update_interval);
 156 
 157         if (value == 0)
 158                 return 0;
 159 
 160         /* find next faster update interval */
 161         for (index = 1; index < number_of_modes; index++) {
 162                 if (mode_to_update_interval[index] <= value)
 163                         return index;
 164         }
 165 
 166         return number_of_modes - 1;
 167 }
 168 
 169 static int sht3x_read_from_command(struct i2c_client *client,
 170                                    struct sht3x_data *data,
 171                                    const char *command,
 172                                    char *buf, int length, u32 wait_time)
 173 {
 174         int ret;
 175 
 176         mutex_lock(&data->i2c_lock);
 177         ret = i2c_master_send(client, command, SHT3X_CMD_LENGTH);
 178 
 179         if (ret != SHT3X_CMD_LENGTH) {
 180                 ret = ret < 0 ? ret : -EIO;
 181                 goto out;
 182         }
 183 
 184         if (wait_time)
 185                 usleep_range(wait_time, wait_time + 1000);
 186 
 187         ret = i2c_master_recv(client, buf, length);
 188         if (ret != length) {
 189                 ret = ret < 0 ? ret : -EIO;
 190                 goto out;
 191         }
 192 
 193         ret = 0;
 194 out:
 195         mutex_unlock(&data->i2c_lock);
 196         return ret;
 197 }
 198 
 199 static int sht3x_extract_temperature(u16 raw)
 200 {
 201         /*
 202          * From datasheet:
 203          * T = -45 + 175 * ST / 2^16
 204          * Adapted for integer fixed point (3 digit) arithmetic.
 205          */
 206         return ((21875 * (int)raw) >> 13) - 45000;
 207 }
 208 
 209 static u32 sht3x_extract_humidity(u16 raw)
 210 {
 211         /*
 212          * From datasheet:
 213          * RH = 100 * SRH / 2^16
 214          * Adapted for integer fixed point (3 digit) arithmetic.
 215          */
 216         return (12500 * (u32)raw) >> 13;
 217 }
 218 
 219 static struct sht3x_data *sht3x_update_client(struct device *dev)
 220 {
 221         struct sht3x_data *data = dev_get_drvdata(dev);
 222         struct i2c_client *client = data->client;
 223         u16 interval_ms = mode_to_update_interval[data->mode];
 224         unsigned long interval_jiffies = msecs_to_jiffies(interval_ms);
 225         unsigned char buf[SHT3X_RESPONSE_LENGTH];
 226         u16 val;
 227         int ret = 0;
 228 
 229         mutex_lock(&data->data_lock);
 230         /*
 231          * Only update cached readings once per update interval in periodic
 232          * mode. In single shot mode the sensor measures values on demand, so
 233          * every time the sysfs interface is called, a measurement is triggered.
 234          * In periodic mode however, the measurement process is handled
 235          * internally by the sensor and reading out sensor values only makes
 236          * sense if a new reading is available.
 237          */
 238         if (time_after(jiffies, data->last_update + interval_jiffies)) {
 239                 ret = sht3x_read_from_command(client, data, data->command, buf,
 240                                               sizeof(buf), data->wait_time);
 241                 if (ret)
 242                         goto out;
 243 
 244                 val = be16_to_cpup((__be16 *)buf);
 245                 data->temperature = sht3x_extract_temperature(val);
 246                 val = be16_to_cpup((__be16 *)(buf + 3));
 247                 data->humidity = sht3x_extract_humidity(val);
 248                 data->last_update = jiffies;
 249         }
 250 
 251 out:
 252         mutex_unlock(&data->data_lock);
 253         if (ret)
 254                 return ERR_PTR(ret);
 255 
 256         return data;
 257 }
 258 
 259 /* sysfs attributes */
 260 static ssize_t temp1_input_show(struct device *dev,
 261                                 struct device_attribute *attr, char *buf)
 262 {
 263         struct sht3x_data *data = sht3x_update_client(dev);
 264 
 265         if (IS_ERR(data))
 266                 return PTR_ERR(data);
 267 
 268         return sprintf(buf, "%d\n", data->temperature);
 269 }
 270 
 271 static ssize_t humidity1_input_show(struct device *dev,
 272                                     struct device_attribute *attr, char *buf)
 273 {
 274         struct sht3x_data *data = sht3x_update_client(dev);
 275 
 276         if (IS_ERR(data))
 277                 return PTR_ERR(data);
 278 
 279         return sprintf(buf, "%u\n", data->humidity);
 280 }
 281 
 282 /*
 283  * limits_update must only be called from probe or with data_lock held
 284  */
 285 static int limits_update(struct sht3x_data *data)
 286 {
 287         int ret;
 288         u8 index;
 289         int temperature;
 290         u32 humidity;
 291         u16 raw;
 292         char buffer[SHT3X_RESPONSE_LENGTH];
 293         const struct sht3x_limit_commands *commands;
 294         struct i2c_client *client = data->client;
 295 
 296         for (index = 0; index < SHT3X_NUM_LIMIT_CMD; index++) {
 297                 commands = &limit_commands[index];
 298                 ret = sht3x_read_from_command(client, data,
 299                                               commands->read_command, buffer,
 300                                               SHT3X_RESPONSE_LENGTH, 0);
 301 
 302                 if (ret)
 303                         return ret;
 304 
 305                 raw = be16_to_cpup((__be16 *)buffer);
 306                 temperature = sht3x_extract_temperature((raw & 0x01ff) << 7);
 307                 humidity = sht3x_extract_humidity(raw & 0xfe00);
 308                 data->temperature_limits[index] = temperature;
 309                 data->humidity_limits[index] = humidity;
 310         }
 311 
 312         return ret;
 313 }
 314 
 315 static ssize_t temp1_limit_show(struct device *dev,
 316                                 struct device_attribute *attr,
 317                                 char *buf)
 318 {
 319         struct sht3x_data *data = dev_get_drvdata(dev);
 320         u8 index = to_sensor_dev_attr(attr)->index;
 321         int temperature_limit = data->temperature_limits[index];
 322 
 323         return scnprintf(buf, PAGE_SIZE, "%d\n", temperature_limit);
 324 }
 325 
 326 static ssize_t humidity1_limit_show(struct device *dev,
 327                                     struct device_attribute *attr,
 328                                     char *buf)
 329 {
 330         struct sht3x_data *data = dev_get_drvdata(dev);
 331         u8 index = to_sensor_dev_attr(attr)->index;
 332         u32 humidity_limit = data->humidity_limits[index];
 333 
 334         return scnprintf(buf, PAGE_SIZE, "%u\n", humidity_limit);
 335 }
 336 
 337 /*
 338  * limit_store must only be called with data_lock held
 339  */
 340 static size_t limit_store(struct device *dev,
 341                           size_t count,
 342                           u8 index,
 343                           int temperature,
 344                           u32 humidity)
 345 {
 346         char buffer[SHT3X_CMD_LENGTH + SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
 347         char *position = buffer;
 348         int ret;
 349         u16 raw;
 350         struct sht3x_data *data = dev_get_drvdata(dev);
 351         struct i2c_client *client = data->client;
 352         const struct sht3x_limit_commands *commands;
 353 
 354         commands = &limit_commands[index];
 355 
 356         memcpy(position, commands->write_command, SHT3X_CMD_LENGTH);
 357         position += SHT3X_CMD_LENGTH;
 358         /*
 359          * ST = (T + 45) / 175 * 2^16
 360          * SRH = RH / 100 * 2^16
 361          * adapted for fixed point arithmetic and packed the same as
 362          * in limit_show()
 363          */
 364         raw = ((u32)(temperature + 45000) * 24543) >> (16 + 7);
 365         raw |= ((humidity * 42950) >> 16) & 0xfe00;
 366 
 367         *((__be16 *)position) = cpu_to_be16(raw);
 368         position += SHT3X_WORD_LEN;
 369         *position = crc8(sht3x_crc8_table,
 370                          position - SHT3X_WORD_LEN,
 371                          SHT3X_WORD_LEN,
 372                          SHT3X_CRC8_INIT);
 373 
 374         mutex_lock(&data->i2c_lock);
 375         ret = i2c_master_send(client, buffer, sizeof(buffer));
 376         mutex_unlock(&data->i2c_lock);
 377 
 378         if (ret != sizeof(buffer))
 379                 return ret < 0 ? ret : -EIO;
 380 
 381         data->temperature_limits[index] = temperature;
 382         data->humidity_limits[index] = humidity;
 383         return count;
 384 }
 385 
 386 static ssize_t temp1_limit_store(struct device *dev,
 387                                  struct device_attribute *attr,
 388                                  const char *buf,
 389                                  size_t count)
 390 {
 391         int temperature;
 392         int ret;
 393         struct sht3x_data *data = dev_get_drvdata(dev);
 394         u8 index = to_sensor_dev_attr(attr)->index;
 395 
 396         ret = kstrtoint(buf, 0, &temperature);
 397         if (ret)
 398                 return ret;
 399 
 400         temperature = clamp_val(temperature, SHT3X_MIN_TEMPERATURE,
 401                                 SHT3X_MAX_TEMPERATURE);
 402         mutex_lock(&data->data_lock);
 403         ret = limit_store(dev, count, index, temperature,
 404                           data->humidity_limits[index]);
 405         mutex_unlock(&data->data_lock);
 406 
 407         return ret;
 408 }
 409 
 410 static ssize_t humidity1_limit_store(struct device *dev,
 411                                      struct device_attribute *attr,
 412                                      const char *buf,
 413                                      size_t count)
 414 {
 415         u32 humidity;
 416         int ret;
 417         struct sht3x_data *data = dev_get_drvdata(dev);
 418         u8 index = to_sensor_dev_attr(attr)->index;
 419 
 420         ret = kstrtou32(buf, 0, &humidity);
 421         if (ret)
 422                 return ret;
 423 
 424         humidity = clamp_val(humidity, SHT3X_MIN_HUMIDITY, SHT3X_MAX_HUMIDITY);
 425         mutex_lock(&data->data_lock);
 426         ret = limit_store(dev, count, index, data->temperature_limits[index],
 427                           humidity);
 428         mutex_unlock(&data->data_lock);
 429 
 430         return ret;
 431 }
 432 
 433 static void sht3x_select_command(struct sht3x_data *data)
 434 {
 435         /*
 436          * In blocking mode (clock stretching mode) the I2C bus
 437          * is blocked for other traffic, thus the call to i2c_master_recv()
 438          * will wait until the data is ready. For non blocking mode, we
 439          * have to wait ourselves.
 440          */
 441         if (data->mode > 0) {
 442                 data->command = sht3x_cmd_measure_periodic_mode;
 443                 data->wait_time = 0;
 444         } else if (data->setup.blocking_io) {
 445                 data->command = data->setup.high_precision ?
 446                                 sht3x_cmd_measure_blocking_hpm :
 447                                 sht3x_cmd_measure_blocking_lpm;
 448                 data->wait_time = 0;
 449         } else {
 450                 if (data->setup.high_precision) {
 451                         data->command = sht3x_cmd_measure_nonblocking_hpm;
 452                         data->wait_time = SHT3X_NONBLOCKING_WAIT_TIME_HPM;
 453                 } else {
 454                         data->command = sht3x_cmd_measure_nonblocking_lpm;
 455                         data->wait_time = SHT3X_NONBLOCKING_WAIT_TIME_LPM;
 456                 }
 457         }
 458 }
 459 
 460 static int status_register_read(struct device *dev,
 461                                 struct device_attribute *attr,
 462                                 char *buffer, int length)
 463 {
 464         int ret;
 465         struct sht3x_data *data = dev_get_drvdata(dev);
 466         struct i2c_client *client = data->client;
 467 
 468         ret = sht3x_read_from_command(client, data, sht3x_cmd_read_status_reg,
 469                                       buffer, length, 0);
 470 
 471         return ret;
 472 }
 473 
 474 static ssize_t temp1_alarm_show(struct device *dev,
 475                                 struct device_attribute *attr,
 476                                 char *buf)
 477 {
 478         char buffer[SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
 479         int ret;
 480 
 481         ret = status_register_read(dev, attr, buffer,
 482                                    SHT3X_WORD_LEN + SHT3X_CRC8_LEN);
 483         if (ret)
 484                 return ret;
 485 
 486         return scnprintf(buf, PAGE_SIZE, "%d\n", !!(buffer[0] & 0x04));
 487 }
 488 
 489 static ssize_t humidity1_alarm_show(struct device *dev,
 490                                     struct device_attribute *attr,
 491                                     char *buf)
 492 {
 493         char buffer[SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
 494         int ret;
 495 
 496         ret = status_register_read(dev, attr, buffer,
 497                                    SHT3X_WORD_LEN + SHT3X_CRC8_LEN);
 498         if (ret)
 499                 return ret;
 500 
 501         return scnprintf(buf, PAGE_SIZE, "%d\n", !!(buffer[0] & 0x08));
 502 }
 503 
 504 static ssize_t heater_enable_show(struct device *dev,
 505                                   struct device_attribute *attr,
 506                                   char *buf)
 507 {
 508         char buffer[SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
 509         int ret;
 510 
 511         ret = status_register_read(dev, attr, buffer,
 512                                    SHT3X_WORD_LEN + SHT3X_CRC8_LEN);
 513         if (ret)
 514                 return ret;
 515 
 516         return scnprintf(buf, PAGE_SIZE, "%d\n", !!(buffer[0] & 0x20));
 517 }
 518 
 519 static ssize_t heater_enable_store(struct device *dev,
 520                                    struct device_attribute *attr,
 521                                    const char *buf,
 522                                    size_t count)
 523 {
 524         struct sht3x_data *data = dev_get_drvdata(dev);
 525         struct i2c_client *client = data->client;
 526         int ret;
 527         bool status;
 528 
 529         ret = kstrtobool(buf, &status);
 530         if (ret)
 531                 return ret;
 532 
 533         mutex_lock(&data->i2c_lock);
 534 
 535         if (status)
 536                 ret = i2c_master_send(client, (char *)&sht3x_cmd_heater_on,
 537                                       SHT3X_CMD_LENGTH);
 538         else
 539                 ret = i2c_master_send(client, (char *)&sht3x_cmd_heater_off,
 540                                       SHT3X_CMD_LENGTH);
 541 
 542         mutex_unlock(&data->i2c_lock);
 543 
 544         return ret;
 545 }
 546 
 547 static ssize_t update_interval_show(struct device *dev,
 548                                     struct device_attribute *attr,
 549                                     char *buf)
 550 {
 551         struct sht3x_data *data = dev_get_drvdata(dev);
 552 
 553         return scnprintf(buf, PAGE_SIZE, "%u\n",
 554                          mode_to_update_interval[data->mode]);
 555 }
 556 
 557 static ssize_t update_interval_store(struct device *dev,
 558                                      struct device_attribute *attr,
 559                                      const char *buf,
 560                                      size_t count)
 561 {
 562         u16 update_interval;
 563         u8 mode;
 564         int ret;
 565         const char *command;
 566         struct sht3x_data *data = dev_get_drvdata(dev);
 567         struct i2c_client *client = data->client;
 568 
 569         ret = kstrtou16(buf, 0, &update_interval);
 570         if (ret)
 571                 return ret;
 572 
 573         mode = get_mode_from_update_interval(update_interval);
 574 
 575         mutex_lock(&data->data_lock);
 576         /* mode did not change */
 577         if (mode == data->mode) {
 578                 mutex_unlock(&data->data_lock);
 579                 return count;
 580         }
 581 
 582         mutex_lock(&data->i2c_lock);
 583         /*
 584          * Abort periodic measure mode.
 585          * To do any changes to the configuration while in periodic mode, we
 586          * have to send a break command to the sensor, which then falls back
 587          * to single shot (mode = 0).
 588          */
 589         if (data->mode > 0) {
 590                 ret = i2c_master_send(client, sht3x_cmd_break,
 591                                       SHT3X_CMD_LENGTH);
 592                 if (ret != SHT3X_CMD_LENGTH)
 593                         goto out;
 594                 data->mode = 0;
 595         }
 596 
 597         if (mode > 0) {
 598                 if (data->setup.high_precision)
 599                         command = periodic_measure_commands_hpm[mode - 1];
 600                 else
 601                         command = periodic_measure_commands_lpm[mode - 1];
 602 
 603                 /* select mode */
 604                 ret = i2c_master_send(client, command, SHT3X_CMD_LENGTH);
 605                 if (ret != SHT3X_CMD_LENGTH)
 606                         goto out;
 607         }
 608 
 609         /* select mode and command */
 610         data->mode = mode;
 611         sht3x_select_command(data);
 612 
 613 out:
 614         mutex_unlock(&data->i2c_lock);
 615         mutex_unlock(&data->data_lock);
 616         if (ret != SHT3X_CMD_LENGTH)
 617                 return ret < 0 ? ret : -EIO;
 618 
 619         return count;
 620 }
 621 
 622 static SENSOR_DEVICE_ATTR_RO(temp1_input, temp1_input, 0);
 623 static SENSOR_DEVICE_ATTR_RO(humidity1_input, humidity1_input, 0);
 624 static SENSOR_DEVICE_ATTR_RW(temp1_max, temp1_limit, limit_max);
 625 static SENSOR_DEVICE_ATTR_RW(humidity1_max, humidity1_limit, limit_max);
 626 static SENSOR_DEVICE_ATTR_RW(temp1_max_hyst, temp1_limit, limit_max_hyst);
 627 static SENSOR_DEVICE_ATTR_RW(humidity1_max_hyst, humidity1_limit,
 628                              limit_max_hyst);
 629 static SENSOR_DEVICE_ATTR_RW(temp1_min, temp1_limit, limit_min);
 630 static SENSOR_DEVICE_ATTR_RW(humidity1_min, humidity1_limit, limit_min);
 631 static SENSOR_DEVICE_ATTR_RW(temp1_min_hyst, temp1_limit, limit_min_hyst);
 632 static SENSOR_DEVICE_ATTR_RW(humidity1_min_hyst, humidity1_limit,
 633                              limit_min_hyst);
 634 static SENSOR_DEVICE_ATTR_RO(temp1_alarm, temp1_alarm, 0);
 635 static SENSOR_DEVICE_ATTR_RO(humidity1_alarm, humidity1_alarm, 0);
 636 static SENSOR_DEVICE_ATTR_RW(heater_enable, heater_enable, 0);
 637 static SENSOR_DEVICE_ATTR_RW(update_interval, update_interval, 0);
 638 
 639 static struct attribute *sht3x_attrs[] = {
 640         &sensor_dev_attr_temp1_input.dev_attr.attr,
 641         &sensor_dev_attr_humidity1_input.dev_attr.attr,
 642         &sensor_dev_attr_temp1_max.dev_attr.attr,
 643         &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 644         &sensor_dev_attr_humidity1_max.dev_attr.attr,
 645         &sensor_dev_attr_humidity1_max_hyst.dev_attr.attr,
 646         &sensor_dev_attr_temp1_min.dev_attr.attr,
 647         &sensor_dev_attr_temp1_min_hyst.dev_attr.attr,
 648         &sensor_dev_attr_humidity1_min.dev_attr.attr,
 649         &sensor_dev_attr_humidity1_min_hyst.dev_attr.attr,
 650         &sensor_dev_attr_temp1_alarm.dev_attr.attr,
 651         &sensor_dev_attr_humidity1_alarm.dev_attr.attr,
 652         &sensor_dev_attr_heater_enable.dev_attr.attr,
 653         &sensor_dev_attr_update_interval.dev_attr.attr,
 654         NULL
 655 };
 656 
 657 static struct attribute *sts3x_attrs[] = {
 658         &sensor_dev_attr_temp1_input.dev_attr.attr,
 659         NULL
 660 };
 661 
 662 ATTRIBUTE_GROUPS(sht3x);
 663 ATTRIBUTE_GROUPS(sts3x);
 664 
 665 static int sht3x_probe(struct i2c_client *client,
 666                        const struct i2c_device_id *id)
 667 {
 668         int ret;
 669         struct sht3x_data *data;
 670         struct device *hwmon_dev;
 671         struct i2c_adapter *adap = client->adapter;
 672         struct device *dev = &client->dev;
 673         const struct attribute_group **attribute_groups;
 674 
 675         /*
 676          * we require full i2c support since the sht3x uses multi-byte read and
 677          * writes as well as multi-byte commands which are not supported by
 678          * the smbus protocol
 679          */
 680         if (!i2c_check_functionality(adap, I2C_FUNC_I2C))
 681                 return -ENODEV;
 682 
 683         ret = i2c_master_send(client, sht3x_cmd_clear_status_reg,
 684                               SHT3X_CMD_LENGTH);
 685         if (ret != SHT3X_CMD_LENGTH)
 686                 return ret < 0 ? ret : -ENODEV;
 687 
 688         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 689         if (!data)
 690                 return -ENOMEM;
 691 
 692         data->setup.blocking_io = false;
 693         data->setup.high_precision = true;
 694         data->mode = 0;
 695         data->last_update = jiffies - msecs_to_jiffies(3000);
 696         data->client = client;
 697         crc8_populate_msb(sht3x_crc8_table, SHT3X_CRC8_POLYNOMIAL);
 698 
 699         if (client->dev.platform_data)
 700                 data->setup = *(struct sht3x_platform_data *)dev->platform_data;
 701 
 702         sht3x_select_command(data);
 703 
 704         mutex_init(&data->i2c_lock);
 705         mutex_init(&data->data_lock);
 706 
 707         /*
 708          * An attempt to read limits register too early
 709          * causes a NACK response from the chip.
 710          * Waiting for an empirical delay of 500 us solves the issue.
 711          */
 712         usleep_range(500, 600);
 713 
 714         ret = limits_update(data);
 715         if (ret)
 716                 return ret;
 717 
 718         if (id->driver_data == sts3x)
 719                 attribute_groups = sts3x_groups;
 720         else
 721                 attribute_groups = sht3x_groups;
 722 
 723         hwmon_dev = devm_hwmon_device_register_with_groups(dev,
 724                                                            client->name,
 725                                                            data,
 726                                                            attribute_groups);
 727 
 728         if (IS_ERR(hwmon_dev))
 729                 dev_dbg(dev, "unable to register hwmon device\n");
 730 
 731         return PTR_ERR_OR_ZERO(hwmon_dev);
 732 }
 733 
 734 /* device ID table */
 735 static const struct i2c_device_id sht3x_ids[] = {
 736         {"sht3x", sht3x},
 737         {"sts3x", sts3x},
 738         {}
 739 };
 740 
 741 MODULE_DEVICE_TABLE(i2c, sht3x_ids);
 742 
 743 static struct i2c_driver sht3x_i2c_driver = {
 744         .driver.name = "sht3x",
 745         .probe       = sht3x_probe,
 746         .id_table    = sht3x_ids,
 747 };
 748 
 749 module_i2c_driver(sht3x_i2c_driver);
 750 
 751 MODULE_AUTHOR("David Frey <david.frey@sensirion.com>");
 752 MODULE_AUTHOR("Pascal Sachs <pascal.sachs@sensirion.com>");
 753 MODULE_DESCRIPTION("Sensirion SHT3x humidity and temperature sensor driver");
 754 MODULE_LICENSE("GPL");