1// SPDX-License-Identifier: GPL-2.0 2/* 3 * Sensirion SCD30 carbon dioxide sensor core driver 4 * 5 * Copyright (c) 2020 Tomasz Duszynski <tomasz.duszynski@octakon.com> 6 */ 7#include <linux/bits.h> 8#include <linux/completion.h> 9#include <linux/delay.h> 10#include <linux/device.h> 11#include <linux/errno.h> 12#include <linux/export.h> 13#include <linux/iio/buffer.h> 14#include <linux/iio/iio.h> 15#include <linux/iio/sysfs.h> 16#include <linux/iio/trigger.h> 17#include <linux/iio/trigger_consumer.h> 18#include <linux/iio/triggered_buffer.h> 19#include <linux/iio/types.h> 20#include <linux/interrupt.h> 21#include <linux/irqreturn.h> 22#include <linux/jiffies.h> 23#include <linux/kernel.h> 24#include <linux/module.h> 25#include <linux/mutex.h> 26#include <linux/regulator/consumer.h> 27#include <linux/string.h> 28#include <linux/sysfs.h> 29#include <linux/types.h> 30#include <asm/byteorder.h> 31 32#include "scd30.h" 33 34#define SCD30_PRESSURE_COMP_MIN_MBAR 700 35#define SCD30_PRESSURE_COMP_MAX_MBAR 1400 36#define SCD30_PRESSURE_COMP_DEFAULT 1013 37#define SCD30_MEAS_INTERVAL_MIN_S 2 38#define SCD30_MEAS_INTERVAL_MAX_S 1800 39#define SCD30_MEAS_INTERVAL_DEFAULT SCD30_MEAS_INTERVAL_MIN_S 40#define SCD30_FRC_MIN_PPM 400 41#define SCD30_FRC_MAX_PPM 2000 42#define SCD30_TEMP_OFFSET_MAX 655360 43#define SCD30_EXTRA_TIMEOUT_PER_S 250 44 45enum { 46 SCD30_CONC, 47 SCD30_TEMP, 48 SCD30_HR, 49}; 50 51static int scd30_command_write(struct scd30_state *state, enum scd30_cmd cmd, u16 arg) 52{ 53 return state->command(state, cmd, arg, NULL, 0); 54} 55 56static int scd30_command_read(struct scd30_state *state, enum scd30_cmd cmd, u16 *val) 57{ 58 __be16 tmp; 59 int ret; 60 61 ret = state->command(state, cmd, 0, &tmp, sizeof(tmp)); 62 *val = be16_to_cpup(&tmp); 63 64 return ret; 65} 66 67static int scd30_reset(struct scd30_state *state) 68{ 69 int ret; 70 u16 val; 71 72 ret = scd30_command_write(state, CMD_RESET, 0); 73 if (ret) 74 return ret; 75 76 /* sensor boots up within 2 secs */ 77 msleep(2000); 78 /* 79 * Power-on-reset causes sensor to produce some glitch on i2c bus and 80 * some controllers end up in error state. Try to recover by placing 81 * any data on the bus. 82 */ 83 scd30_command_read(state, CMD_MEAS_READY, &val); 84 85 return 0; 86} 87 88/* simplified float to fixed point conversion with a scaling factor of 0.01 */ 89static int scd30_float_to_fp(int float32) 90{ 91 int fraction, shift, 92 mantissa = float32 & GENMASK(22, 0), 93 sign = (float32 & BIT(31)) ? -1 : 1, 94 exp = (float32 & ~BIT(31)) >> 23; 95 96 /* special case 0 */ 97 if (!exp && !mantissa) 98 return 0; 99 100 exp -= 127; 101 if (exp < 0) { 102 exp = -exp; 103 /* return values ranging from 1 to 99 */ 104 return sign * ((((BIT(23) + mantissa) * 100) >> 23) >> exp); 105 } 106 107 /* return values starting at 100 */ 108 shift = 23 - exp; 109 float32 = BIT(exp) + (mantissa >> shift); 110 fraction = mantissa & GENMASK(shift - 1, 0); 111 112 return sign * (float32 * 100 + ((fraction * 100) >> shift)); 113} 114 115static int scd30_read_meas(struct scd30_state *state) 116{ 117 int i, ret; 118 119 ret = state->command(state, CMD_READ_MEAS, 0, state->meas, sizeof(state->meas)); 120 if (ret) 121 return ret; 122 123 be32_to_cpu_array(state->meas, (__be32 *)state->meas, ARRAY_SIZE(state->meas)); 124 125 for (i = 0; i < ARRAY_SIZE(state->meas); i++) 126 state->meas[i] = scd30_float_to_fp(state->meas[i]); 127 128 /* 129 * co2 is left unprocessed while temperature and humidity are scaled 130 * to milli deg C and milli percent respectively. 131 */ 132 state->meas[SCD30_TEMP] *= 10; 133 state->meas[SCD30_HR] *= 10; 134 135 return 0; 136} 137 138static int scd30_wait_meas_irq(struct scd30_state *state) 139{ 140 int ret, timeout; 141 142 reinit_completion(&state->meas_ready); 143 enable_irq(state->irq); 144 timeout = msecs_to_jiffies(state->meas_interval * (1000 + SCD30_EXTRA_TIMEOUT_PER_S)); 145 ret = wait_for_completion_interruptible_timeout(&state->meas_ready, timeout); 146 if (ret > 0) 147 ret = 0; 148 else if (!ret) 149 ret = -ETIMEDOUT; 150 151 disable_irq(state->irq); 152 153 return ret; 154} 155 156static int scd30_wait_meas_poll(struct scd30_state *state) 157{ 158 int timeout = state->meas_interval * SCD30_EXTRA_TIMEOUT_PER_S, tries = 5; 159 160 do { 161 int ret; 162 u16 val; 163 164 ret = scd30_command_read(state, CMD_MEAS_READY, &val); 165 if (ret) 166 return -EIO; 167 168 /* new measurement available */ 169 if (val) 170 break; 171 172 msleep_interruptible(timeout); 173 } while (--tries); 174 175 return tries ? 0 : -ETIMEDOUT; 176} 177 178static int scd30_read_poll(struct scd30_state *state) 179{ 180 int ret; 181 182 ret = scd30_wait_meas_poll(state); 183 if (ret) 184 return ret; 185 186 return scd30_read_meas(state); 187} 188 189static int scd30_read(struct scd30_state *state) 190{ 191 if (state->irq > 0) 192 return scd30_wait_meas_irq(state); 193 194 return scd30_read_poll(state); 195} 196 197static int scd30_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, 198 int *val, int *val2, long mask) 199{ 200 struct scd30_state *state = iio_priv(indio_dev); 201 int ret = -EINVAL; 202 u16 tmp; 203 204 mutex_lock(&state->lock); 205 switch (mask) { 206 case IIO_CHAN_INFO_RAW: 207 case IIO_CHAN_INFO_PROCESSED: 208 if (chan->output) { 209 *val = state->pressure_comp; 210 ret = IIO_VAL_INT; 211 break; 212 } 213 214 ret = iio_device_claim_direct_mode(indio_dev); 215 if (ret) 216 break; 217 218 ret = scd30_read(state); 219 if (ret) { 220 iio_device_release_direct_mode(indio_dev); 221 break; 222 } 223 224 *val = state->meas[chan->address]; 225 iio_device_release_direct_mode(indio_dev); 226 ret = IIO_VAL_INT; 227 break; 228 case IIO_CHAN_INFO_SCALE: 229 *val = 0; 230 *val2 = 1; 231 ret = IIO_VAL_INT_PLUS_MICRO; 232 break; 233 case IIO_CHAN_INFO_SAMP_FREQ: 234 ret = scd30_command_read(state, CMD_MEAS_INTERVAL, &tmp); 235 if (ret) 236 break; 237 238 *val = 0; 239 *val2 = 1000000000 / tmp; 240 ret = IIO_VAL_INT_PLUS_NANO; 241 break; 242 case IIO_CHAN_INFO_CALIBBIAS: 243 ret = scd30_command_read(state, CMD_TEMP_OFFSET, &tmp); 244 if (ret) 245 break; 246 247 *val = tmp; 248 ret = IIO_VAL_INT; 249 break; 250 } 251 mutex_unlock(&state->lock); 252 253 return ret; 254} 255 256static int scd30_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, 257 int val, int val2, long mask) 258{ 259 struct scd30_state *state = iio_priv(indio_dev); 260 int ret = -EINVAL; 261 262 mutex_lock(&state->lock); 263 switch (mask) { 264 case IIO_CHAN_INFO_SAMP_FREQ: 265 if (val) 266 break; 267 268 val = 1000000000 / val2; 269 if (val < SCD30_MEAS_INTERVAL_MIN_S || val > SCD30_MEAS_INTERVAL_MAX_S) 270 break; 271 272 ret = scd30_command_write(state, CMD_MEAS_INTERVAL, val); 273 if (ret) 274 break; 275 276 state->meas_interval = val; 277 break; 278 case IIO_CHAN_INFO_RAW: 279 switch (chan->type) { 280 case IIO_PRESSURE: 281 if (val < SCD30_PRESSURE_COMP_MIN_MBAR || 282 val > SCD30_PRESSURE_COMP_MAX_MBAR) 283 break; 284 285 ret = scd30_command_write(state, CMD_START_MEAS, val); 286 if (ret) 287 break; 288 289 state->pressure_comp = val; 290 break; 291 default: 292 break; 293 } 294 break; 295 case IIO_CHAN_INFO_CALIBBIAS: 296 if (val < 0 || val > SCD30_TEMP_OFFSET_MAX) 297 break; 298 /* 299 * Manufacturer does not explicitly specify min/max sensible 300 * values hence check is omitted for simplicity. 301 */ 302 ret = scd30_command_write(state, CMD_TEMP_OFFSET / 10, val); 303 } 304 mutex_unlock(&state->lock); 305 306 return ret; 307} 308 309static int scd30_write_raw_get_fmt(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, 310 long mask) 311{ 312 switch (mask) { 313 case IIO_CHAN_INFO_SAMP_FREQ: 314 return IIO_VAL_INT_PLUS_NANO; 315 case IIO_CHAN_INFO_RAW: 316 case IIO_CHAN_INFO_CALIBBIAS: 317 return IIO_VAL_INT; 318 } 319 320 return -EINVAL; 321} 322 323static const int scd30_pressure_raw_available[] = { 324 SCD30_PRESSURE_COMP_MIN_MBAR, 1, SCD30_PRESSURE_COMP_MAX_MBAR, 325}; 326 327static const int scd30_temp_calibbias_available[] = { 328 0, 10, SCD30_TEMP_OFFSET_MAX, 329}; 330 331static int scd30_read_avail(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, 332 const int **vals, int *type, int *length, long mask) 333{ 334 switch (mask) { 335 case IIO_CHAN_INFO_RAW: 336 *vals = scd30_pressure_raw_available; 337 *type = IIO_VAL_INT; 338 339 return IIO_AVAIL_RANGE; 340 case IIO_CHAN_INFO_CALIBBIAS: 341 *vals = scd30_temp_calibbias_available; 342 *type = IIO_VAL_INT; 343 344 return IIO_AVAIL_RANGE; 345 } 346 347 return -EINVAL; 348} 349 350static ssize_t sampling_frequency_available_show(struct device *dev, struct device_attribute *attr, 351 char *buf) 352{ 353 int i = SCD30_MEAS_INTERVAL_MIN_S; 354 ssize_t len = 0; 355 356 do { 357 len += sysfs_emit_at(buf, len, "0.%09u ", 1000000000 / i); 358 /* 359 * Not all values fit PAGE_SIZE buffer hence print every 6th 360 * (each frequency differs by 6s in time domain from the 361 * adjacent). Unlisted but valid ones are still accepted. 362 */ 363 i += 6; 364 } while (i <= SCD30_MEAS_INTERVAL_MAX_S); 365 366 buf[len - 1] = '\n'; 367 368 return len; 369} 370 371static ssize_t calibration_auto_enable_show(struct device *dev, struct device_attribute *attr, 372 char *buf) 373{ 374 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 375 struct scd30_state *state = iio_priv(indio_dev); 376 int ret; 377 u16 val; 378 379 mutex_lock(&state->lock); 380 ret = scd30_command_read(state, CMD_ASC, &val); 381 mutex_unlock(&state->lock); 382 383 return ret ?: sysfs_emit(buf, "%d\n", val); 384} 385 386static ssize_t calibration_auto_enable_store(struct device *dev, struct device_attribute *attr, 387 const char *buf, size_t len) 388{ 389 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 390 struct scd30_state *state = iio_priv(indio_dev); 391 bool val; 392 int ret; 393 394 ret = kstrtobool(buf, &val); 395 if (ret) 396 return ret; 397 398 mutex_lock(&state->lock); 399 ret = scd30_command_write(state, CMD_ASC, val); 400 mutex_unlock(&state->lock); 401 402 return ret ?: len; 403} 404 405static ssize_t calibration_forced_value_show(struct device *dev, struct device_attribute *attr, 406 char *buf) 407{ 408 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 409 struct scd30_state *state = iio_priv(indio_dev); 410 int ret; 411 u16 val; 412 413 mutex_lock(&state->lock); 414 ret = scd30_command_read(state, CMD_FRC, &val); 415 mutex_unlock(&state->lock); 416 417 return ret ?: sysfs_emit(buf, "%d\n", val); 418} 419 420static ssize_t calibration_forced_value_store(struct device *dev, struct device_attribute *attr, 421 const char *buf, size_t len) 422{ 423 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 424 struct scd30_state *state = iio_priv(indio_dev); 425 int ret; 426 u16 val; 427 428 ret = kstrtou16(buf, 0, &val); 429 if (ret) 430 return ret; 431 432 if (val < SCD30_FRC_MIN_PPM || val > SCD30_FRC_MAX_PPM) 433 return -EINVAL; 434 435 mutex_lock(&state->lock); 436 ret = scd30_command_write(state, CMD_FRC, val); 437 mutex_unlock(&state->lock); 438 439 return ret ?: len; 440} 441 442static IIO_DEVICE_ATTR_RO(sampling_frequency_available, 0); 443static IIO_DEVICE_ATTR_RW(calibration_auto_enable, 0); 444static IIO_DEVICE_ATTR_RW(calibration_forced_value, 0); 445 446static struct attribute *scd30_attrs[] = { 447 &iio_dev_attr_sampling_frequency_available.dev_attr.attr, 448 &iio_dev_attr_calibration_auto_enable.dev_attr.attr, 449 &iio_dev_attr_calibration_forced_value.dev_attr.attr, 450 NULL 451}; 452 453static const struct attribute_group scd30_attr_group = { 454 .attrs = scd30_attrs, 455}; 456 457static const struct iio_info scd30_info = { 458 .attrs = &scd30_attr_group, 459 .read_raw = scd30_read_raw, 460 .write_raw = scd30_write_raw, 461 .write_raw_get_fmt = scd30_write_raw_get_fmt, 462 .read_avail = scd30_read_avail, 463}; 464 465#define SCD30_CHAN_SCAN_TYPE(_sign, _realbits) .scan_type = { \ 466 .sign = _sign, \ 467 .realbits = _realbits, \ 468 .storagebits = 32, \ 469 .endianness = IIO_CPU, \ 470} 471 472static const struct iio_chan_spec scd30_channels[] = { 473 { 474 /* 475 * this channel is special in a sense we are pretending that 476 * sensor is able to change measurement chamber pressure but in 477 * fact we're just setting pressure compensation value 478 */ 479 .type = IIO_PRESSURE, 480 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), 481 .info_mask_separate_available = BIT(IIO_CHAN_INFO_RAW), 482 .output = 1, 483 .scan_index = -1, 484 }, 485 { 486 .type = IIO_CONCENTRATION, 487 .channel2 = IIO_MOD_CO2, 488 .address = SCD30_CONC, 489 .scan_index = SCD30_CONC, 490 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | 491 BIT(IIO_CHAN_INFO_SCALE), 492 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), 493 .modified = 1, 494 495 SCD30_CHAN_SCAN_TYPE('u', 20), 496 }, 497 { 498 .type = IIO_TEMP, 499 .address = SCD30_TEMP, 500 .scan_index = SCD30_TEMP, 501 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) | 502 BIT(IIO_CHAN_INFO_CALIBBIAS), 503 .info_mask_separate_available = BIT(IIO_CHAN_INFO_CALIBBIAS), 504 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), 505 506 SCD30_CHAN_SCAN_TYPE('s', 18), 507 }, 508 { 509 .type = IIO_HUMIDITYRELATIVE, 510 .address = SCD30_HR, 511 .scan_index = SCD30_HR, 512 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), 513 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), 514 515 SCD30_CHAN_SCAN_TYPE('u', 17), 516 }, 517 IIO_CHAN_SOFT_TIMESTAMP(3), 518}; 519 520static int scd30_suspend(struct device *dev) 521{ 522 struct iio_dev *indio_dev = dev_get_drvdata(dev); 523 struct scd30_state *state = iio_priv(indio_dev); 524 int ret; 525 526 ret = scd30_command_write(state, CMD_STOP_MEAS, 0); 527 if (ret) 528 return ret; 529 530 return regulator_disable(state->vdd); 531} 532 533static int scd30_resume(struct device *dev) 534{ 535 struct iio_dev *indio_dev = dev_get_drvdata(dev); 536 struct scd30_state *state = iio_priv(indio_dev); 537 int ret; 538 539 ret = regulator_enable(state->vdd); 540 if (ret) 541 return ret; 542 543 return scd30_command_write(state, CMD_START_MEAS, state->pressure_comp); 544} 545 546EXPORT_NS_SIMPLE_DEV_PM_OPS(scd30_pm_ops, scd30_suspend, scd30_resume, IIO_SCD30); 547 548static void scd30_stop_meas(void *data) 549{ 550 struct scd30_state *state = data; 551 552 scd30_command_write(state, CMD_STOP_MEAS, 0); 553} 554 555static void scd30_disable_regulator(void *data) 556{ 557 struct scd30_state *state = data; 558 559 regulator_disable(state->vdd); 560} 561 562static irqreturn_t scd30_irq_handler(int irq, void *priv) 563{ 564 struct iio_dev *indio_dev = priv; 565 566 if (iio_buffer_enabled(indio_dev)) { 567 iio_trigger_poll(indio_dev->trig); 568 569 return IRQ_HANDLED; 570 } 571 572 return IRQ_WAKE_THREAD; 573} 574 575static irqreturn_t scd30_irq_thread_handler(int irq, void *priv) 576{ 577 struct iio_dev *indio_dev = priv; 578 struct scd30_state *state = iio_priv(indio_dev); 579 int ret; 580 581 ret = scd30_read_meas(state); 582 if (ret) 583 goto out; 584 585 complete_all(&state->meas_ready); 586out: 587 return IRQ_HANDLED; 588} 589 590static irqreturn_t scd30_trigger_handler(int irq, void *p) 591{ 592 struct iio_poll_func *pf = p; 593 struct iio_dev *indio_dev = pf->indio_dev; 594 struct scd30_state *state = iio_priv(indio_dev); 595 struct { 596 int data[SCD30_MEAS_COUNT]; 597 s64 ts __aligned(8); 598 } scan; 599 int ret; 600 601 mutex_lock(&state->lock); 602 if (!iio_trigger_using_own(indio_dev)) 603 ret = scd30_read_poll(state); 604 else 605 ret = scd30_read_meas(state); 606 memset(&scan, 0, sizeof(scan)); 607 memcpy(scan.data, state->meas, sizeof(state->meas)); 608 mutex_unlock(&state->lock); 609 if (ret) 610 goto out; 611 612 iio_push_to_buffers_with_timestamp(indio_dev, &scan, iio_get_time_ns(indio_dev)); 613out: 614 iio_trigger_notify_done(indio_dev->trig); 615 return IRQ_HANDLED; 616} 617 618static int scd30_set_trigger_state(struct iio_trigger *trig, bool state) 619{ 620 struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig); 621 struct scd30_state *st = iio_priv(indio_dev); 622 623 if (state) 624 enable_irq(st->irq); 625 else 626 disable_irq(st->irq); 627 628 return 0; 629} 630 631static const struct iio_trigger_ops scd30_trigger_ops = { 632 .set_trigger_state = scd30_set_trigger_state, 633 .validate_device = iio_trigger_validate_own_device, 634}; 635 636static int scd30_setup_trigger(struct iio_dev *indio_dev) 637{ 638 struct scd30_state *state = iio_priv(indio_dev); 639 struct device *dev = indio_dev->dev.parent; 640 struct iio_trigger *trig; 641 int ret; 642 643 trig = devm_iio_trigger_alloc(dev, "%s-dev%d", indio_dev->name, 644 iio_device_id(indio_dev)); 645 if (!trig) 646 return dev_err_probe(dev, -ENOMEM, "failed to allocate trigger\n"); 647 648 trig->ops = &scd30_trigger_ops; 649 iio_trigger_set_drvdata(trig, indio_dev); 650 651 ret = devm_iio_trigger_register(dev, trig); 652 if (ret) 653 return ret; 654 655 indio_dev->trig = iio_trigger_get(trig); 656 657 /* 658 * Interrupt is enabled just before taking a fresh measurement 659 * and disabled afterwards. This means we need to ensure it is not 660 * enabled here to keep calls to enable/disable balanced. 661 */ 662 ret = devm_request_threaded_irq(dev, state->irq, scd30_irq_handler, 663 scd30_irq_thread_handler, 664 IRQF_TRIGGER_HIGH | IRQF_ONESHOT | 665 IRQF_NO_AUTOEN, 666 indio_dev->name, indio_dev); 667 if (ret) 668 return dev_err_probe(dev, ret, "failed to request irq\n"); 669 670 return 0; 671} 672 673int scd30_probe(struct device *dev, int irq, const char *name, void *priv, 674 scd30_command_t command) 675{ 676 static const unsigned long scd30_scan_masks[] = { 0x07, 0x00 }; 677 struct scd30_state *state; 678 struct iio_dev *indio_dev; 679 int ret; 680 u16 val; 681 682 indio_dev = devm_iio_device_alloc(dev, sizeof(*state)); 683 if (!indio_dev) 684 return -ENOMEM; 685 686 state = iio_priv(indio_dev); 687 state->dev = dev; 688 state->priv = priv; 689 state->irq = irq; 690 state->pressure_comp = SCD30_PRESSURE_COMP_DEFAULT; 691 state->meas_interval = SCD30_MEAS_INTERVAL_DEFAULT; 692 state->command = command; 693 mutex_init(&state->lock); 694 init_completion(&state->meas_ready); 695 696 dev_set_drvdata(dev, indio_dev); 697 698 indio_dev->info = &scd30_info; 699 indio_dev->name = name; 700 indio_dev->channels = scd30_channels; 701 indio_dev->num_channels = ARRAY_SIZE(scd30_channels); 702 indio_dev->modes = INDIO_DIRECT_MODE; 703 indio_dev->available_scan_masks = scd30_scan_masks; 704 705 state->vdd = devm_regulator_get(dev, "vdd"); 706 if (IS_ERR(state->vdd)) 707 return dev_err_probe(dev, PTR_ERR(state->vdd), "failed to get regulator\n"); 708 709 ret = regulator_enable(state->vdd); 710 if (ret) 711 return ret; 712 713 ret = devm_add_action_or_reset(dev, scd30_disable_regulator, state); 714 if (ret) 715 return ret; 716 717 ret = scd30_reset(state); 718 if (ret) 719 return dev_err_probe(dev, ret, "failed to reset device\n"); 720 721 if (state->irq > 0) { 722 ret = scd30_setup_trigger(indio_dev); 723 if (ret) 724 return dev_err_probe(dev, ret, "failed to setup trigger\n"); 725 } 726 727 ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL, scd30_trigger_handler, NULL); 728 if (ret) 729 return ret; 730 731 ret = scd30_command_read(state, CMD_FW_VERSION, &val); 732 if (ret) 733 return dev_err_probe(dev, ret, "failed to read firmware version\n"); 734 dev_info(dev, "firmware version: %d.%d\n", val >> 8, (char)val); 735 736 ret = scd30_command_write(state, CMD_MEAS_INTERVAL, state->meas_interval); 737 if (ret) 738 return dev_err_probe(dev, ret, "failed to set measurement interval\n"); 739 740 ret = scd30_command_write(state, CMD_START_MEAS, state->pressure_comp); 741 if (ret) 742 return dev_err_probe(dev, ret, "failed to start measurement\n"); 743 744 ret = devm_add_action_or_reset(dev, scd30_stop_meas, state); 745 if (ret) 746 return ret; 747 748 return devm_iio_device_register(dev, indio_dev); 749} 750EXPORT_SYMBOL_NS(scd30_probe, IIO_SCD30); 751 752MODULE_AUTHOR("Tomasz Duszynski <tomasz.duszynski@octakon.com>"); 753MODULE_DESCRIPTION("Sensirion SCD30 carbon dioxide sensor core driver"); 754MODULE_LICENSE("GPL v2"); 755