drivers/hwmon/sht3x.c

   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/debugfs.h>
  14 #include <linux/delay.h>
  15 #include <linux/err.h>
  16 #include <linux/hwmon.h>
  17 #include <linux/hwmon-sysfs.h>
  18 #include <linux/i2c.h>
  19 #include <linux/init.h>
  20 #include <linux/kernel.h>
  21 #include <linux/module.h>
  22 #include <linux/slab.h>
  23 #include <linux/jiffies.h>
  24
  25 /* commands (high repeatability mode) */
  26 static const unsigned char sht3x_cmd_measure_single_hpm[] = { 0x24, 0x00 };
  27
  28 /* commands (medium repeatability mode) */
  29 static const unsigned char sht3x_cmd_measure_single_mpm[] = { 0x24, 0x0b };
  30
  31 /* commands (low repeatability mode) */
  32 static const unsigned char sht3x_cmd_measure_single_lpm[] = { 0x24, 0x16 };
  33
  34 /* commands for periodic mode */
  35 static const unsigned char sht3x_cmd_measure_periodic_mode[]   = { 0xe0, 0x00 };
  36 static const unsigned char sht3x_cmd_break[]                   = { 0x30, 0x93 };
  37
  38 /* commands for heater control */
  39 static const unsigned char sht3x_cmd_heater_on[]               = { 0x30, 0x6d };
  40 static const unsigned char sht3x_cmd_heater_off[]              = { 0x30, 0x66 };
  41
  42 /* other commands */
  43 static const unsigned char sht3x_cmd_read_status_reg[]         = { 0xf3, 0x2d };
  44 static const unsigned char sht3x_cmd_clear_status_reg[]        = { 0x30, 0x41 };
  45 static const unsigned char sht3x_cmd_read_serial_number[]      = { 0x37, 0x80 };
  46
  47 static struct dentry *debugfs;
  48
  49 /* delays for single-shot mode i2c commands, both in us */
  50 #define SHT3X_SINGLE_WAIT_TIME_HPM  15000
  51 #define SHT3X_SINGLE_WAIT_TIME_MPM   6000
  52 #define SHT3X_SINGLE_WAIT_TIME_LPM   4000
  53
  54 #define SHT3X_WORD_LEN         2
  55 #define SHT3X_CMD_LENGTH       2
  56 #define SHT3X_CRC8_LEN         1
  57 #define SHT3X_RESPONSE_LENGTH  6
  58 #define SHT3X_CRC8_POLYNOMIAL  0x31
  59 #define SHT3X_CRC8_INIT        0xFF
  60 #define SHT3X_MIN_TEMPERATURE  -45000
  61 #define SHT3X_MAX_TEMPERATURE  130000
  62 #define SHT3X_MIN_HUMIDITY     0
  63 #define SHT3X_MAX_HUMIDITY     100000
  64
  65 enum sht3x_chips {
  66         sht3x,
  67         sts3x,
  68 };
  69
  70 enum sht3x_limits {
  71         limit_max = 0,
  72         limit_max_hyst,
  73         limit_min,
  74         limit_min_hyst,
  75 };
  76
  77 enum sht3x_repeatability {
  78         low_repeatability,
  79         medium_repeatability,
  80         high_repeatability,
  81 };
  82
  83 DECLARE_CRC8_TABLE(sht3x_crc8_table);
  84
  85 /* periodic measure commands (high repeatability mode) */
  86 static const char periodic_measure_commands_hpm[][SHT3X_CMD_LENGTH] = {
  87         /* 0.5 measurements per second */
  88         {0x20, 0x32},
  89         /* 1 measurements per second */
  90         {0x21, 0x30},
  91         /* 2 measurements per second */
  92         {0x22, 0x36},
  93         /* 4 measurements per second */
  94         {0x23, 0x34},
  95         /* 10 measurements per second */
  96         {0x27, 0x37},
  97 };
  98
  99 /* periodic measure commands (medium repeatability) */
 100 static const char periodic_measure_commands_mpm[][SHT3X_CMD_LENGTH] = {
 101         /* 0.5 measurements per second */
 102         {0x20, 0x24},
 103         /* 1 measurements per second */
 104         {0x21, 0x26},
 105         /* 2 measurements per second */
 106         {0x22, 0x20},
 107         /* 4 measurements per second */
 108         {0x23, 0x22},
 109         /* 10 measurements per second */
 110         {0x27, 0x21},
 111 };
 112
 113 /* periodic measure commands (low repeatability mode) */
 114 static const char periodic_measure_commands_lpm[][SHT3X_CMD_LENGTH] = {
 115         /* 0.5 measurements per second */
 116         {0x20, 0x2f},
 117         /* 1 measurements per second */
 118         {0x21, 0x2d},
 119         /* 2 measurements per second */
 120         {0x22, 0x2b},
 121         /* 4 measurements per second */
 122         {0x23, 0x29},
 123         /* 10 measurements per second */
 124         {0x27, 0x2a},
 125 };
 126
 127 struct sht3x_limit_commands {
 128         const char read_command[SHT3X_CMD_LENGTH];
 129         const char write_command[SHT3X_CMD_LENGTH];
 130 };
 131
 132 static const struct sht3x_limit_commands limit_commands[] = {
 133         /* temp1_max, humidity1_max */
 134         [limit_max] = { {0xe1, 0x1f}, {0x61, 0x1d} },
 135         /* temp_1_max_hyst, humidity1_max_hyst */
 136         [limit_max_hyst] = { {0xe1, 0x14}, {0x61, 0x16} },
 137         /* temp1_min, humidity1_min */
 138         [limit_min] = { {0xe1, 0x02}, {0x61, 0x00} },
 139         /* temp_1_min_hyst, humidity1_min_hyst */
 140         [limit_min_hyst] = { {0xe1, 0x09}, {0x61, 0x0B} },
 141 };
 142
 143 #define SHT3X_NUM_LIMIT_CMD  ARRAY_SIZE(limit_commands)
 144
 145 static const u16 mode_to_update_interval[] = {
 146            0,
 147         2000,
 148         1000,
 149          500,
 150          250,
 151          100,
 152 };
 153
 154 static const struct hwmon_channel_info * const sht3x_channel_info[] = {
 155         HWMON_CHANNEL_INFO(chip, HWMON_C_UPDATE_INTERVAL),
 156         HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_MIN |
 157                                 HWMON_T_MIN_HYST | HWMON_T_MAX |
 158                                 HWMON_T_MAX_HYST | HWMON_T_ALARM),
 159         HWMON_CHANNEL_INFO(humidity, HWMON_H_INPUT | HWMON_H_MIN |
 160                                 HWMON_H_MIN_HYST | HWMON_H_MAX |
 161                                 HWMON_H_MAX_HYST | HWMON_H_ALARM),
 162         NULL,
 163 };
 164
 165 struct sht3x_data {
 166         struct i2c_client *client;
 167         enum sht3x_chips chip_id;
 168         struct mutex i2c_lock; /* lock for sending i2c commands */
 169         struct mutex data_lock; /* lock for updating driver data */
 170         struct dentry *sensor_dir;
 171
 172         u8 mode;
 173         const unsigned char *command;
 174         u32 wait_time;                  /* in us*/
 175         unsigned long last_update;      /* last update in periodic mode*/
 176         enum sht3x_repeatability repeatability;
 177         u32 serial_number;
 178
 179         /*
 180          * cached values for temperature and humidity and limits
 181          * the limits arrays have the following order:
 182          * max, max_hyst, min, min_hyst
 183          */
 184         int temperature;
 185         int temperature_limits[SHT3X_NUM_LIMIT_CMD];
 186         u32 humidity;
 187         u32 humidity_limits[SHT3X_NUM_LIMIT_CMD];
 188 };
 189
 190 static u8 get_mode_from_update_interval(u16 value)
 191 {
 192         size_t index;
 193         u8 number_of_modes = ARRAY_SIZE(mode_to_update_interval);
 194
 195         if (value == 0)
 196                 return 0;
 197
 198         /* find next faster update interval */
 199         for (index = 1; index < number_of_modes; index++) {
 200                 if (mode_to_update_interval[index] <= value)
 201                         return index;
 202         }
 203
 204         return number_of_modes - 1;
 205 }
 206
 207 static int sht3x_read_from_command(struct i2c_client *client,
 208                                    struct sht3x_data *data,
 209                                    const char *command,
 210                                    char *buf, int length, u32 wait_time)
 211 {
 212         int ret;
 213
 214         mutex_lock(&data->i2c_lock);
 215         ret = i2c_master_send(client, command, SHT3X_CMD_LENGTH);
 216
 217         if (ret != SHT3X_CMD_LENGTH) {
 218                 ret = ret < 0 ? ret : -EIO;
 219                 goto out;
 220         }
 221
 222         if (wait_time)
 223                 usleep_range(wait_time, wait_time + 1000);
 224
 225         ret = i2c_master_recv(client, buf, length);
 226         if (ret != length) {
 227                 ret = ret < 0 ? ret : -EIO;
 228                 goto out;
 229         }
 230
 231         ret = 0;
 232 out:
 233         mutex_unlock(&data->i2c_lock);
 234         return ret;
 235 }
 236
 237 static int sht3x_extract_temperature(u16 raw)
 238 {
 239         /*
 240          * From datasheet:
 241          * T = -45 + 175 * ST / 2^16
 242          * Adapted for integer fixed point (3 digit) arithmetic.
 243          */
 244         return ((21875 * (int)raw) >> 13) - 45000;
 245 }
 246
 247 static u32 sht3x_extract_humidity(u16 raw)
 248 {
 249         /*
 250          * From datasheet:
 251          * RH = 100 * SRH / 2^16
 252          * Adapted for integer fixed point (3 digit) arithmetic.
 253          */
 254         return (12500 * (u32)raw) >> 13;
 255 }
 256
 257 static struct sht3x_data *sht3x_update_client(struct device *dev)
 258 {
 259         struct sht3x_data *data = dev_get_drvdata(dev);
 260         struct i2c_client *client = data->client;
 261         u16 interval_ms = mode_to_update_interval[data->mode];
 262         unsigned long interval_jiffies = msecs_to_jiffies(interval_ms);
 263         unsigned char buf[SHT3X_RESPONSE_LENGTH];
 264         u16 val;
 265         int ret = 0;
 266
 267         mutex_lock(&data->data_lock);
 268         /*
 269          * Only update cached readings once per update interval in periodic
 270          * mode. In single shot mode the sensor measures values on demand, so
 271          * every time the sysfs interface is called, a measurement is triggered.
 272          * In periodic mode however, the measurement process is handled
 273          * internally by the sensor and reading out sensor values only makes
 274          * sense if a new reading is available.
 275          */
 276         if (time_after(jiffies, data->last_update + interval_jiffies)) {
 277                 ret = sht3x_read_from_command(client, data, data->command, buf,
 278                                               sizeof(buf), data->wait_time);
 279                 if (ret)
 280                         goto out;
 281
 282                 val = be16_to_cpup((__be16 *)buf);
 283                 data->temperature = sht3x_extract_temperature(val);
 284                 val = be16_to_cpup((__be16 *)(buf + 3));
 285                 data->humidity = sht3x_extract_humidity(val);
 286                 data->last_update = jiffies;
 287         }
 288
 289 out:
 290         mutex_unlock(&data->data_lock);
 291         if (ret)
 292                 return ERR_PTR(ret);
 293
 294         return data;
 295 }
 296
 297 static int temp1_input_read(struct device *dev)
 298 {
 299         struct sht3x_data *data = sht3x_update_client(dev);
 300
 301         if (IS_ERR(data))
 302                 return PTR_ERR(data);
 303
 304         return data->temperature;
 305 }
 306
 307 static int humidity1_input_read(struct device *dev)
 308 {
 309         struct sht3x_data *data = sht3x_update_client(dev);
 310
 311         if (IS_ERR(data))
 312                 return PTR_ERR(data);
 313
 314         return data->humidity;
 315 }
 316
 317 /*
 318  * limits_update must only be called from probe or with data_lock held
 319  */
 320 static int limits_update(struct sht3x_data *data)
 321 {
 322         int ret;
 323         u8 index;
 324         int temperature;
 325         u32 humidity;
 326         u16 raw;
 327         char buffer[SHT3X_RESPONSE_LENGTH];
 328         const struct sht3x_limit_commands *commands;
 329         struct i2c_client *client = data->client;
 330
 331         for (index = 0; index < SHT3X_NUM_LIMIT_CMD; index++) {
 332                 commands = &limit_commands[index];
 333                 ret = sht3x_read_from_command(client, data,
 334                                               commands->read_command, buffer,
 335                                               SHT3X_RESPONSE_LENGTH, 0);
 336
 337                 if (ret)
 338                         return ret;
 339
 340                 raw = be16_to_cpup((__be16 *)buffer);
 341                 temperature = sht3x_extract_temperature((raw & 0x01ff) << 7);
 342                 humidity = sht3x_extract_humidity(raw & 0xfe00);
 343                 data->temperature_limits[index] = temperature;
 344                 data->humidity_limits[index] = humidity;
 345         }
 346
 347         return ret;
 348 }
 349
 350 static int temp1_limit_read(struct device *dev, int index)
 351 {
 352         struct sht3x_data *data = dev_get_drvdata(dev);
 353
 354         return data->temperature_limits[index];
 355 }
 356
 357 static int humidity1_limit_read(struct device *dev, int index)
 358 {
 359         struct sht3x_data *data = dev_get_drvdata(dev);
 360
 361         return data->humidity_limits[index];
 362 }
 363
 364 /*
 365  * limit_write must only be called with data_lock held
 366  */
 367 static size_t limit_write(struct device *dev,
 368                           u8 index,
 369                           int temperature,
 370                           u32 humidity)
 371 {
 372         char buffer[SHT3X_CMD_LENGTH + SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
 373         char *position = buffer;
 374         int ret;
 375         u16 raw;
 376         struct sht3x_data *data = dev_get_drvdata(dev);
 377         struct i2c_client *client = data->client;
 378         const struct sht3x_limit_commands *commands;
 379
 380         commands = &limit_commands[index];
 381
 382         memcpy(position, commands->write_command, SHT3X_CMD_LENGTH);
 383         position += SHT3X_CMD_LENGTH;
 384         /*
 385          * ST = (T + 45) / 175 * 2^16
 386          * SRH = RH / 100 * 2^16
 387          * adapted for fixed point arithmetic and packed the same as
 388          * in limit_read()
 389          */
 390         raw = ((u32)(temperature + 45000) * 24543) >> (16 + 7);
 391         raw |= ((humidity * 42950) >> 16) & 0xfe00;
 392
 393         *((__be16 *)position) = cpu_to_be16(raw);
 394         position += SHT3X_WORD_LEN;
 395         *position = crc8(sht3x_crc8_table,
 396                          position - SHT3X_WORD_LEN,
 397                          SHT3X_WORD_LEN,
 398                          SHT3X_CRC8_INIT);
 399
 400         mutex_lock(&data->i2c_lock);
 401         ret = i2c_master_send(client, buffer, sizeof(buffer));
 402         mutex_unlock(&data->i2c_lock);
 403
 404         if (ret != sizeof(buffer))
 405                 return ret < 0 ? ret : -EIO;
 406
 407         data->temperature_limits[index] = temperature;
 408         data->humidity_limits[index] = humidity;
 409
 410         return 0;
 411 }
 412
 413 static int temp1_limit_write(struct device *dev, int index, int val)
 414 {
 415         int temperature;
 416         int ret;
 417         struct sht3x_data *data = dev_get_drvdata(dev);
 418
 419         temperature = clamp_val(val, SHT3X_MIN_TEMPERATURE,
 420                                 SHT3X_MAX_TEMPERATURE);
 421         mutex_lock(&data->data_lock);
 422         ret = limit_write(dev, index, temperature,
 423                           data->humidity_limits[index]);
 424         mutex_unlock(&data->data_lock);
 425
 426         return ret;
 427 }
 428
 429 static int humidity1_limit_write(struct device *dev, int index, int val)
 430 {
 431         u32 humidity;
 432         int ret;
 433         struct sht3x_data *data = dev_get_drvdata(dev);
 434
 435         humidity = clamp_val(val, SHT3X_MIN_HUMIDITY, SHT3X_MAX_HUMIDITY);
 436         mutex_lock(&data->data_lock);
 437         ret = limit_write(dev, index, data->temperature_limits[index],
 438                           humidity);
 439         mutex_unlock(&data->data_lock);
 440
 441         return ret;
 442 }
 443
 444 static void sht3x_select_command(struct sht3x_data *data)
 445 {
 446         /*
 447          * For single-shot mode, only non blocking mode is support,
 448          * we have to wait ourselves for result.
 449          */
 450         if (data->mode > 0) {
 451                 data->command = sht3x_cmd_measure_periodic_mode;
 452                 data->wait_time = 0;
 453         } else {
 454                 if (data->repeatability == high_repeatability) {
 455                         data->command = sht3x_cmd_measure_single_hpm;
 456                         data->wait_time = SHT3X_SINGLE_WAIT_TIME_HPM;
 457                 } else if (data->repeatability ==  medium_repeatability) {
 458                         data->command = sht3x_cmd_measure_single_mpm;
 459                         data->wait_time = SHT3X_SINGLE_WAIT_TIME_MPM;
 460                 } else {
 461                         data->command = sht3x_cmd_measure_single_lpm;
 462                         data->wait_time = SHT3X_SINGLE_WAIT_TIME_LPM;
 463                 }
 464         }
 465 }
 466
 467 static int status_register_read(struct device *dev,
 468                                 char *buffer, int length)
 469 {
 470         int ret;
 471         struct sht3x_data *data = dev_get_drvdata(dev);
 472         struct i2c_client *client = data->client;
 473
 474         ret = sht3x_read_from_command(client, data, sht3x_cmd_read_status_reg,
 475                                       buffer, length, 0);
 476
 477         return ret;
 478 }
 479
 480 static int temp1_alarm_read(struct device *dev)
 481 {
 482         char buffer[SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
 483         int ret;
 484
 485         ret = status_register_read(dev, buffer,
 486                                    SHT3X_WORD_LEN + SHT3X_CRC8_LEN);
 487         if (ret)
 488                 return ret;
 489
 490         return !!(buffer[0] & 0x04);
 491 }
 492
 493 static int humidity1_alarm_read(struct device *dev)
 494 {
 495         char buffer[SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
 496         int ret;
 497
 498         ret = status_register_read(dev, buffer,
 499                                    SHT3X_WORD_LEN + SHT3X_CRC8_LEN);
 500         if (ret)
 501                 return ret;
 502
 503         return !!(buffer[0] & 0x08);
 504 }
 505
 506 static ssize_t heater_enable_show(struct device *dev,
 507                                   struct device_attribute *attr,
 508                                   char *buf)
 509 {
 510         char buffer[SHT3X_WORD_LEN + SHT3X_CRC8_LEN];
 511         int ret;
 512
 513         ret = status_register_read(dev, buffer,
 514                                    SHT3X_WORD_LEN + SHT3X_CRC8_LEN);
 515         if (ret)
 516                 return ret;
 517
 518         return sysfs_emit(buf, "%d\n", !!(buffer[0] & 0x20));
 519 }
 520
 521 static ssize_t heater_enable_store(struct device *dev,
 522                                    struct device_attribute *attr,
 523                                    const char *buf,
 524                                    size_t count)
 525 {
 526         struct sht3x_data *data = dev_get_drvdata(dev);
 527         struct i2c_client *client = data->client;
 528         int ret;
 529         bool status;
 530
 531         ret = kstrtobool(buf, &status);
 532         if (ret)
 533                 return ret;
 534
 535         mutex_lock(&data->i2c_lock);
 536
 537         if (status)
 538                 ret = i2c_master_send(client, (char *)&sht3x_cmd_heater_on,
 539                                       SHT3X_CMD_LENGTH);
 540         else
 541                 ret = i2c_master_send(client, (char *)&sht3x_cmd_heater_off,
 542                                       SHT3X_CMD_LENGTH);
 543
 544         mutex_unlock(&data->i2c_lock);
 545
 546         return ret;
 547 }
 548
 549 static int update_interval_read(struct device *dev)
 550 {
 551         struct sht3x_data *data = dev_get_drvdata(dev);
 552
 553         return mode_to_update_interval[data->mode];
 554 }
 555
 556 static int update_interval_write(struct device *dev, int val)
 557 {
 558         u8 mode;
 559         int ret;
 560         const char *command;
 561         struct sht3x_data *data = dev_get_drvdata(dev);
 562         struct i2c_client *client = data->client;
 563
 564         mode = get_mode_from_update_interval(val);
 565
 566         mutex_lock(&data->data_lock);
 567         /* mode did not change */
 568         if (mode == data->mode) {
 569                 mutex_unlock(&data->data_lock);
 570                 return 0;
 571         }
 572
 573         mutex_lock(&data->i2c_lock);
 574         /*
 575          * Abort periodic measure mode.
 576          * To do any changes to the configuration while in periodic mode, we
 577          * have to send a break command to the sensor, which then falls back
 578          * to single shot (mode = 0).
 579          */
 580         if (data->mode > 0) {
 581                 ret = i2c_master_send(client, sht3x_cmd_break,
 582                                       SHT3X_CMD_LENGTH);
 583                 if (ret != SHT3X_CMD_LENGTH)
 584                         goto out;
 585                 data->mode = 0;
 586         }
 587
 588         if (mode > 0) {
 589                 if (data->repeatability == high_repeatability)
 590                         command = periodic_measure_commands_hpm[mode - 1];
 591                 else if (data->repeatability == medium_repeatability)
 592                         command = periodic_measure_commands_mpm[mode - 1];
 593                 else
 594                         command = periodic_measure_commands_lpm[mode - 1];
 595
 596                 /* select mode */
 597                 ret = i2c_master_send(client, command, SHT3X_CMD_LENGTH);
 598                 if (ret != SHT3X_CMD_LENGTH)
 599                         goto out;
 600         }
 601
 602         /* select mode and command */
 603         data->mode = mode;
 604         sht3x_select_command(data);
 605
 606 out:
 607         mutex_unlock(&data->i2c_lock);
 608         mutex_unlock(&data->data_lock);
 609         if (ret != SHT3X_CMD_LENGTH)
 610                 return ret < 0 ? ret : -EIO;
 611
 612         return 0;
 613 }
 614
 615 static ssize_t repeatability_show(struct device *dev,
 616                                   struct device_attribute *attr,
 617                                   char *buf)
 618 {
 619         struct sht3x_data *data = dev_get_drvdata(dev);
 620
 621         return sysfs_emit(buf, "%d\n", data->repeatability);
 622 }
 623
 624 static ssize_t repeatability_store(struct device *dev,
 625                                    struct device_attribute *attr,
 626                                    const char *buf,
 627                                    size_t count)
 628 {
 629         int ret;
 630         u8 val;
 631
 632         struct sht3x_data *data = dev_get_drvdata(dev);
 633
 634         ret = kstrtou8(buf, 0, &val);
 635         if (ret)
 636                 return ret;
 637
 638         if (val > 2)
 639                 return -EINVAL;
 640
 641         data->repeatability = val;
 642
 643         return count;
 644 }
 645
 646 static SENSOR_DEVICE_ATTR_RW(heater_enable, heater_enable, 0);
 647 static SENSOR_DEVICE_ATTR_RW(repeatability, repeatability, 0);
 648
 649 static struct attribute *sht3x_attrs[] = {
 650         &sensor_dev_attr_heater_enable.dev_attr.attr,
 651         &sensor_dev_attr_repeatability.dev_attr.attr,
 652         NULL
 653 };
 654
 655 ATTRIBUTE_GROUPS(sht3x);
 656
 657 static umode_t sht3x_is_visible(const void *data, enum hwmon_sensor_types type,
 658                                 u32 attr, int channel)
 659 {
 660         const struct sht3x_data *chip_data = data;
 661
 662         switch (type) {
 663         case hwmon_chip:
 664                 switch (attr) {
 665                 case hwmon_chip_update_interval:
 666                         return 0644;
 667                 default:
 668                         break;
 669                 }
 670                 break;
 671         case hwmon_temp:
 672                 switch (attr) {
 673                 case hwmon_temp_input:
 674                 case hwmon_temp_alarm:
 675                         return 0444;
 676                 case hwmon_temp_max:
 677                 case hwmon_temp_max_hyst:
 678                 case hwmon_temp_min:
 679                 case hwmon_temp_min_hyst:
 680                         return 0644;
 681                 default:
 682                         break;
 683                 }
 684                 break;
 685         case hwmon_humidity:
 686                 if (chip_data->chip_id == sts3x)
 687                         break;
 688                 switch (attr) {
 689                 case hwmon_humidity_input:
 690                 case hwmon_humidity_alarm:
 691                         return 0444;
 692                 case hwmon_humidity_max:
 693                 case hwmon_humidity_max_hyst:
 694                 case hwmon_humidity_min:
 695                 case hwmon_humidity_min_hyst:
 696                         return 0644;
 697                 default:
 698                         break;
 699                 }
 700                 break;
 701         default:
 702                 break;
 703         }
 704
 705         return 0;
 706 }
 707
 708 static int sht3x_read(struct device *dev, enum hwmon_sensor_types type,
 709                       u32 attr, int channel, long *val)
 710 {
 711         enum sht3x_limits index;
 712
 713         switch (type) {
 714         case hwmon_chip:
 715                 switch (attr) {
 716                 case hwmon_chip_update_interval:
 717                         *val = update_interval_read(dev);
 718                         break;
 719                 default:
 720                         return -EOPNOTSUPP;
 721                 }
 722                 break;
 723         case hwmon_temp:
 724                 switch (attr) {
 725                 case hwmon_temp_input:
 726                         *val = temp1_input_read(dev);
 727                         break;
 728                 case hwmon_temp_alarm:
 729                         *val = temp1_alarm_read(dev);
 730                         break;
 731                 case hwmon_temp_max:
 732                         index = limit_max;
 733                         *val = temp1_limit_read(dev, index);
 734                         break;
 735                 case hwmon_temp_max_hyst:
 736                         index = limit_max_hyst;
 737                         *val = temp1_limit_read(dev, index);
 738                         break;
 739                 case hwmon_temp_min:
 740                         index = limit_min;
 741                         *val = temp1_limit_read(dev, index);
 742                         break;
 743                 case hwmon_temp_min_hyst:
 744                         index = limit_min_hyst;
 745                         *val = temp1_limit_read(dev, index);
 746                         break;
 747                 default:
 748                         return -EOPNOTSUPP;
 749                 }
 750                 break;
 751         case hwmon_humidity:
 752                 switch (attr) {
 753                 case hwmon_humidity_input:
 754                         *val = humidity1_input_read(dev);
 755                         break;
 756                 case hwmon_humidity_alarm:
 757                         *val = humidity1_alarm_read(dev);
 758                         break;
 759                 case hwmon_humidity_max:
 760                         index = limit_max;
 761                         *val = humidity1_limit_read(dev, index);
 762                         break;
 763                 case hwmon_humidity_max_hyst:
 764                         index = limit_max_hyst;
 765                         *val = humidity1_limit_read(dev, index);
 766                         break;
 767                 case hwmon_humidity_min:
 768                         index = limit_min;
 769                         *val = humidity1_limit_read(dev, index);
 770                         break;
 771                 case hwmon_humidity_min_hyst:
 772                         index = limit_min_hyst;
 773                         *val = humidity1_limit_read(dev, index);
 774                         break;
 775                 default:
 776                         return -EOPNOTSUPP;
 777                 }
 778                 break;
 779         default:
 780                 return -EOPNOTSUPP;
 781         }
 782
 783         return 0;
 784 }
 785
 786 static int sht3x_write(struct device *dev, enum hwmon_sensor_types type,
 787                        u32 attr, int channel, long val)
 788 {
 789         enum sht3x_limits index;
 790
 791         switch (type) {
 792         case hwmon_chip:
 793                 switch (attr) {
 794                 case hwmon_chip_update_interval:
 795                         return update_interval_write(dev, val);
 796                 default:
 797                         return -EOPNOTSUPP;
 798                 }
 799         case hwmon_temp:
 800                 switch (attr) {
 801                 case hwmon_temp_max:
 802                         index = limit_max;
 803                         break;
 804                 case hwmon_temp_max_hyst:
 805                         index = limit_max_hyst;
 806                         break;
 807                 case hwmon_temp_min:
 808                         index = limit_min;
 809                         break;
 810                 case hwmon_temp_min_hyst:
 811                         index = limit_min_hyst;
 812                         break;
 813                 default:
 814                         return -EOPNOTSUPP;
 815                 }
 816                 return temp1_limit_write(dev, index, val);
 817         case hwmon_humidity:
 818                 switch (attr) {
 819                 case hwmon_humidity_max:
 820                         index = limit_max;
 821                         break;
 822                 case hwmon_humidity_max_hyst:
 823                         index = limit_max_hyst;
 824                         break;
 825                 case hwmon_humidity_min:
 826                         index = limit_min;
 827                         break;
 828                 case hwmon_humidity_min_hyst:
 829                         index = limit_min_hyst;
 830                         break;
 831                 default:
 832                         return -EOPNOTSUPP;
 833                 }
 834                 return humidity1_limit_write(dev, index, val);
 835         default:
 836                 return -EOPNOTSUPP;
 837         }
 838 }
 839
 840 static void sht3x_debugfs_init(struct sht3x_data *data)
 841 {
 842         char name[32];
 843
 844         snprintf(name, sizeof(name), "i2c%u-%02x",
 845                  data->client->adapter->nr, data->client->addr);
 846         data->sensor_dir = debugfs_create_dir(name, debugfs);
 847         debugfs_create_u32("serial_number", 0444,
 848                            data->sensor_dir, &data->serial_number);
 849 }
 850
 851 static void sht3x_debugfs_remove(void *sensor_dir)
 852 {
 853         debugfs_remove_recursive(sensor_dir);
 854 }
 855
 856 static int sht3x_serial_number_read(struct sht3x_data *data)
 857 {
 858         int ret;
 859         char buffer[SHT3X_RESPONSE_LENGTH];
 860         struct i2c_client *client = data->client;
 861
 862         ret = sht3x_read_from_command(client, data,
 863                                       sht3x_cmd_read_serial_number,
 864                                       buffer,
 865                                       SHT3X_RESPONSE_LENGTH, 0);
 866         if (ret)
 867                 return ret;
 868
 869         data->serial_number = (buffer[0] << 24) | (buffer[1] << 16) |
 870                               (buffer[3] << 8) | buffer[4];
 871         return ret;
 872 }
 873
 874 static const struct hwmon_ops sht3x_ops = {
 875         .is_visible = sht3x_is_visible,
 876         .read = sht3x_read,
 877         .write = sht3x_write,
 878 };
 879
 880 static const struct hwmon_chip_info sht3x_chip_info = {
 881         .ops = &sht3x_ops,
 882         .info = sht3x_channel_info,
 883 };
 884
 885 static int sht3x_probe(struct i2c_client *client)
 886 {
 887         int ret;
 888         struct sht3x_data *data;
 889         struct device *hwmon_dev;
 890         struct i2c_adapter *adap = client->adapter;
 891         struct device *dev = &client->dev;
 892
 893         /*
 894          * we require full i2c support since the sht3x uses multi-byte read and
 895          * writes as well as multi-byte commands which are not supported by
 896          * the smbus protocol
 897          */
 898         if (!i2c_check_functionality(adap, I2C_FUNC_I2C))
 899                 return -ENODEV;
 900
 901         ret = i2c_master_send(client, sht3x_cmd_clear_status_reg,
 902                               SHT3X_CMD_LENGTH);
 903         if (ret != SHT3X_CMD_LENGTH)
 904                 return ret < 0 ? ret : -ENODEV;
 905
 906         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 907         if (!data)
 908                 return -ENOMEM;
 909
 910         data->repeatability = high_repeatability;
 911         data->mode = 0;
 912         data->last_update = jiffies - msecs_to_jiffies(3000);
 913         data->client = client;
 914         data->chip_id = (uintptr_t)i2c_get_match_data(client);
 915         crc8_populate_msb(sht3x_crc8_table, SHT3X_CRC8_POLYNOMIAL);
 916
 917         sht3x_select_command(data);
 918
 919         mutex_init(&data->i2c_lock);
 920         mutex_init(&data->data_lock);
 921
 922         /*
 923          * An attempt to read limits register too early
 924          * causes a NACK response from the chip.
 925          * Waiting for an empirical delay of 500 us solves the issue.
 926          */
 927         usleep_range(500, 600);
 928
 929         ret = limits_update(data);
 930         if (ret)
 931                 return ret;
 932
 933         ret = sht3x_serial_number_read(data);
 934         if (ret) {
 935                 dev_dbg(dev, "unable to read serial number\n");
 936         } else {
 937                 sht3x_debugfs_init(data);
 938                 ret = devm_add_action_or_reset(dev,
 939                                                sht3x_debugfs_remove,
 940                                                data->sensor_dir);
 941                 if (ret)
 942                         return ret;
 943         }
 944
 945         hwmon_dev = devm_hwmon_device_register_with_info(dev,
 946                                                          client->name,
 947                                                          data,
 948                                                          &sht3x_chip_info,
 949                                                          sht3x_groups);
 950
 951         if (IS_ERR(hwmon_dev))
 952                 dev_dbg(dev, "unable to register hwmon device\n");
 953
 954         return PTR_ERR_OR_ZERO(hwmon_dev);
 955 }
 956
 957 /* device ID table */
 958 static const struct i2c_device_id sht3x_ids[] = {
 959         {"sht3x", sht3x},
 960         {"sts3x", sts3x},
 961         {}
 962 };
 963
 964 MODULE_DEVICE_TABLE(i2c, sht3x_ids);
 965
 966 static struct i2c_driver sht3x_i2c_driver = {
 967         .driver.name = "sht3x",
 968         .probe       = sht3x_probe,
 969         .id_table    = sht3x_ids,
 970 };
 971
 972 static int __init sht3x_init(void)
 973 {
 974         debugfs = debugfs_create_dir("sht3x", NULL);
 975         return i2c_add_driver(&sht3x_i2c_driver);
 976 }
 977 module_init(sht3x_init);
 978
 979 static void __exit sht3x_cleanup(void)
 980 {
 981         debugfs_remove_recursive(debugfs);
 982         i2c_del_driver(&sht3x_i2c_driver);
 983 }
 984 module_exit(sht3x_cleanup);
 985
 986 MODULE_AUTHOR("David Frey <david.frey@sensirion.com>");
 987 MODULE_AUTHOR("Pascal Sachs <pascal.sachs@sensirion.com>");
 988 MODULE_DESCRIPTION("Sensirion SHT3x humidity and temperature sensor driver");
 989 MODULE_LICENSE("GPL");