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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 | // SPDX-License-Identifier: GPL-2.0 /* * Sensirion SCD4X carbon dioxide sensor i2c driver * * Copyright (C) 2021 Protonic Holland * Author: Roan van Dijk <roan@protonic.nl> * * I2C slave address: 0x62 * * Datasheets: * https://www.sensirion.com/file/datasheet_scd4x */ #include <asm/unaligned.h> #include <linux/crc8.h> #include <linux/delay.h> #include <linux/device.h> #include <linux/i2c.h> #include <linux/iio/buffer.h> #include <linux/iio/iio.h> #include <linux/iio/sysfs.h> #include <linux/iio/trigger.h> #include <linux/iio/trigger_consumer.h> #include <linux/iio/triggered_buffer.h> #include <linux/iio/types.h> #include <linux/kernel.h> #include <linux/mutex.h> #include <linux/string.h> #include <linux/sysfs.h> #include <linux/types.h> #define SCD4X_CRC8_POLYNOMIAL 0x31 #define SCD4X_TIMEOUT_ERR 1000 #define SCD4X_READ_BUF_SIZE 9 #define SCD4X_COMMAND_BUF_SIZE 2 #define SCD4X_WRITE_BUF_SIZE 5 #define SCD4X_FRC_MIN_PPM 0 #define SCD4X_FRC_MAX_PPM 2000 #define SCD4X_READY_MASK 0x01 /*Commands SCD4X*/ enum scd4x_cmd { CMD_START_MEAS = 0x21b1, CMD_READ_MEAS = 0xec05, CMD_STOP_MEAS = 0x3f86, CMD_SET_TEMP_OFFSET = 0x241d, CMD_GET_TEMP_OFFSET = 0x2318, CMD_FRC = 0x362f, CMD_SET_ASC = 0x2416, CMD_GET_ASC = 0x2313, CMD_GET_DATA_READY = 0xe4b8, }; enum scd4x_channel_idx { SCD4X_CO2, SCD4X_TEMP, SCD4X_HR, }; struct scd4x_state { struct i2c_client *client; /* maintain access to device, to prevent concurrent reads/writes */ struct mutex lock; struct regulator *vdd; }; DECLARE_CRC8_TABLE(scd4x_crc8_table); static int scd4x_i2c_xfer(struct scd4x_state *state, char *txbuf, int txsize, char *rxbuf, int rxsize) { struct i2c_client *client = state->client; int ret; ret = i2c_master_send(client, txbuf, txsize); if (ret < 0) return ret; if (ret != txsize) return -EIO; if (rxsize == 0) return 0; ret = i2c_master_recv(client, rxbuf, rxsize); if (ret < 0) return ret; if (ret != rxsize) return -EIO; return 0; } static int scd4x_send_command(struct scd4x_state *state, enum scd4x_cmd cmd) { char buf[SCD4X_COMMAND_BUF_SIZE]; int ret; /* * Measurement needs to be stopped before sending commands. * Except stop and start command. */ if ((cmd != CMD_STOP_MEAS) && (cmd != CMD_START_MEAS)) { ret = scd4x_send_command(state, CMD_STOP_MEAS); if (ret) return ret; /* execution time for stopping measurement */ msleep_interruptible(500); } put_unaligned_be16(cmd, buf); ret = scd4x_i2c_xfer(state, buf, 2, buf, 0); if (ret) return ret; if ((cmd != CMD_STOP_MEAS) && (cmd != CMD_START_MEAS)) { ret = scd4x_send_command(state, CMD_START_MEAS); if (ret) return ret; } return 0; } static int scd4x_read(struct scd4x_state *state, enum scd4x_cmd cmd, void *response, int response_sz) { struct i2c_client *client = state->client; char buf[SCD4X_READ_BUF_SIZE]; char *rsp = response; int i, ret; char crc; /* * Measurement needs to be stopped before sending commands. * Except for reading measurement and data ready command. */ if ((cmd != CMD_GET_DATA_READY) && (cmd != CMD_READ_MEAS)) { ret = scd4x_send_command(state, CMD_STOP_MEAS); if (ret) return ret; /* execution time for stopping measurement */ msleep_interruptible(500); } /* CRC byte for every 2 bytes of data */ response_sz += response_sz / 2; put_unaligned_be16(cmd, buf); ret = scd4x_i2c_xfer(state, buf, 2, buf, response_sz); if (ret) return ret; for (i = 0; i < response_sz; i += 3) { crc = crc8(scd4x_crc8_table, buf + i, 2, CRC8_INIT_VALUE); if (crc != buf[i + 2]) { dev_err(&client->dev, "CRC error\n"); return -EIO; } *rsp++ = buf[i]; *rsp++ = buf[i + 1]; } /* start measurement */ if ((cmd != CMD_GET_DATA_READY) && (cmd != CMD_READ_MEAS)) { ret = scd4x_send_command(state, CMD_START_MEAS); if (ret) return ret; } return 0; } static int scd4x_write(struct scd4x_state *state, enum scd4x_cmd cmd, uint16_t arg) { char buf[SCD4X_WRITE_BUF_SIZE]; int ret; char crc; put_unaligned_be16(cmd, buf); put_unaligned_be16(arg, buf + 2); crc = crc8(scd4x_crc8_table, buf + 2, 2, CRC8_INIT_VALUE); buf[4] = crc; /* measurement needs to be stopped before sending commands */ ret = scd4x_send_command(state, CMD_STOP_MEAS); if (ret) return ret; /* execution time */ msleep_interruptible(500); ret = scd4x_i2c_xfer(state, buf, SCD4X_WRITE_BUF_SIZE, buf, 0); if (ret) return ret; /* start measurement, except for forced calibration command */ if (cmd != CMD_FRC) { ret = scd4x_send_command(state, CMD_START_MEAS); if (ret) return ret; } return 0; } static int scd4x_write_and_fetch(struct scd4x_state *state, enum scd4x_cmd cmd, uint16_t arg, void *response, int response_sz) { struct i2c_client *client = state->client; char buf[SCD4X_READ_BUF_SIZE]; char *rsp = response; int i, ret; char crc; ret = scd4x_write(state, CMD_FRC, arg); if (ret) goto err; /* execution time */ msleep_interruptible(400); /* CRC byte for every 2 bytes of data */ response_sz += response_sz / 2; ret = i2c_master_recv(client, buf, response_sz); if (ret < 0) goto err; if (ret != response_sz) { ret = -EIO; goto err; } for (i = 0; i < response_sz; i += 3) { crc = crc8(scd4x_crc8_table, buf + i, 2, CRC8_INIT_VALUE); if (crc != buf[i + 2]) { dev_err(&client->dev, "CRC error\n"); ret = -EIO; goto err; } *rsp++ = buf[i]; *rsp++ = buf[i + 1]; } return scd4x_send_command(state, CMD_START_MEAS); err: /* * on error try to start the measurement, * puts sensor back into continuous measurement */ scd4x_send_command(state, CMD_START_MEAS); return ret; } static int scd4x_read_meas(struct scd4x_state *state, uint16_t *meas) { int i, ret; __be16 buf[3]; ret = scd4x_read(state, CMD_READ_MEAS, buf, sizeof(buf)); if (ret) return ret; for (i = 0; i < ARRAY_SIZE(buf); i++) meas[i] = be16_to_cpu(buf[i]); return 0; } static int scd4x_wait_meas_poll(struct scd4x_state *state) { struct i2c_client *client = state->client; int tries = 6; int ret; do { __be16 bval; uint16_t val; ret = scd4x_read(state, CMD_GET_DATA_READY, &bval, sizeof(bval)); if (ret) return -EIO; val = be16_to_cpu(bval); /* new measurement available */ if (val & 0x7FF) return 0; msleep_interruptible(1000); } while (--tries); /* try to start sensor on timeout */ ret = scd4x_send_command(state, CMD_START_MEAS); if (ret) dev_err(&client->dev, "failed to start measurement: %d\n", ret); return -ETIMEDOUT; } static int scd4x_read_poll(struct scd4x_state *state, uint16_t *buf) { int ret; ret = scd4x_wait_meas_poll(state); if (ret) return ret; return scd4x_read_meas(state, buf); } static int scd4x_read_channel(struct scd4x_state *state, int chan) { int ret; uint16_t buf[3]; ret = scd4x_read_poll(state, buf); if (ret) return ret; return buf[chan]; } static int scd4x_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long mask) { struct scd4x_state *state = iio_priv(indio_dev); int ret; __be16 tmp; switch (mask) { case IIO_CHAN_INFO_RAW: ret = iio_device_claim_direct_mode(indio_dev); if (ret) return ret; mutex_lock(&state->lock); ret = scd4x_read_channel(state, chan->address); mutex_unlock(&state->lock); iio_device_release_direct_mode(indio_dev); if (ret < 0) return ret; *val = ret; return IIO_VAL_INT; case IIO_CHAN_INFO_SCALE: if (chan->type == IIO_CONCENTRATION) { *val = 0; *val2 = 100; return IIO_VAL_INT_PLUS_MICRO; } else if (chan->type == IIO_TEMP) { *val = 175000; *val2 = 65536; return IIO_VAL_FRACTIONAL; } else if (chan->type == IIO_HUMIDITYRELATIVE) { *val = 100000; *val2 = 65536; return IIO_VAL_FRACTIONAL; } return -EINVAL; case IIO_CHAN_INFO_OFFSET: *val = -16852; *val2 = 114286; return IIO_VAL_INT_PLUS_MICRO; case IIO_CHAN_INFO_CALIBBIAS: mutex_lock(&state->lock); ret = scd4x_read(state, CMD_GET_TEMP_OFFSET, &tmp, sizeof(tmp)); mutex_unlock(&state->lock); if (ret) return ret; *val = be16_to_cpu(tmp); return IIO_VAL_INT; default: return -EINVAL; } } static int scd4x_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int val, int val2, long mask) { struct scd4x_state *state = iio_priv(indio_dev); int ret = 0; switch (mask) { case IIO_CHAN_INFO_CALIBBIAS: mutex_lock(&state->lock); ret = scd4x_write(state, CMD_SET_TEMP_OFFSET, val); mutex_unlock(&state->lock); return ret; default: return -EINVAL; } } static ssize_t calibration_auto_enable_show(struct device *dev, struct device_attribute *attr, char *buf) { struct iio_dev *indio_dev = dev_to_iio_dev(dev); struct scd4x_state *state = iio_priv(indio_dev); int ret; __be16 bval; u16 val; mutex_lock(&state->lock); ret = scd4x_read(state, CMD_GET_ASC, &bval, sizeof(bval)); mutex_unlock(&state->lock); if (ret) { dev_err(dev, "failed to read automatic calibration"); return ret; } val = (be16_to_cpu(bval) & SCD4X_READY_MASK) ? 1 : 0; return sysfs_emit(buf, "%d\n", val); } static ssize_t calibration_auto_enable_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t len) { struct iio_dev *indio_dev = dev_to_iio_dev(dev); struct scd4x_state *state = iio_priv(indio_dev); bool val; int ret; uint16_t value; ret = kstrtobool(buf, &val); if (ret) return ret; value = val; mutex_lock(&state->lock); ret = scd4x_write(state, CMD_SET_ASC, value); mutex_unlock(&state->lock); if (ret) dev_err(dev, "failed to set automatic calibration"); return ret ?: len; } static ssize_t calibration_forced_value_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t len) { struct iio_dev *indio_dev = dev_to_iio_dev(dev); struct scd4x_state *state = iio_priv(indio_dev); uint16_t val, arg; int ret; ret = kstrtou16(buf, 0, &arg); if (ret) return ret; if (arg < SCD4X_FRC_MIN_PPM || arg > SCD4X_FRC_MAX_PPM) return -EINVAL; mutex_lock(&state->lock); ret = scd4x_write_and_fetch(state, CMD_FRC, arg, &val, sizeof(val)); mutex_unlock(&state->lock); if (ret) return ret; if (val == 0xff) { dev_err(dev, "forced calibration has failed"); return -EINVAL; } return len; } static IIO_DEVICE_ATTR_RW(calibration_auto_enable, 0); static IIO_DEVICE_ATTR_WO(calibration_forced_value, 0); static IIO_CONST_ATTR(calibration_forced_value_available, __stringify([SCD4X_FRC_MIN_PPM 1 SCD4X_FRC_MAX_PPM])); static struct attribute *scd4x_attrs[] = { &iio_dev_attr_calibration_auto_enable.dev_attr.attr, &iio_dev_attr_calibration_forced_value.dev_attr.attr, &iio_const_attr_calibration_forced_value_available.dev_attr.attr, NULL }; static const struct attribute_group scd4x_attr_group = { .attrs = scd4x_attrs, }; static const struct iio_info scd4x_info = { .attrs = &scd4x_attr_group, .read_raw = scd4x_read_raw, .write_raw = scd4x_write_raw, }; static const struct iio_chan_spec scd4x_channels[] = { { .type = IIO_CONCENTRATION, .channel2 = IIO_MOD_CO2, .modified = 1, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), .address = SCD4X_CO2, .scan_index = SCD4X_CO2, .scan_type = { .sign = 'u', .realbits = 16, .storagebits = 16, .endianness = IIO_BE, }, }, { .type = IIO_TEMP, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_CALIBBIAS), .address = SCD4X_TEMP, .scan_index = SCD4X_TEMP, .scan_type = { .sign = 'u', .realbits = 16, .storagebits = 16, .endianness = IIO_BE, }, }, { .type = IIO_HUMIDITYRELATIVE, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), .address = SCD4X_HR, .scan_index = SCD4X_HR, .scan_type = { .sign = 'u', .realbits = 16, .storagebits = 16, .endianness = IIO_BE, }, }, }; static int scd4x_suspend(struct device *dev) { struct iio_dev *indio_dev = dev_get_drvdata(dev); struct scd4x_state *state = iio_priv(indio_dev); int ret; ret = scd4x_send_command(state, CMD_STOP_MEAS); if (ret) return ret; return regulator_disable(state->vdd); } static int scd4x_resume(struct device *dev) { struct iio_dev *indio_dev = dev_get_drvdata(dev); struct scd4x_state *state = iio_priv(indio_dev); int ret; ret = regulator_enable(state->vdd); if (ret) return ret; return scd4x_send_command(state, CMD_START_MEAS); } static DEFINE_SIMPLE_DEV_PM_OPS(scd4x_pm_ops, scd4x_suspend, scd4x_resume); static void scd4x_stop_meas(void *state) { scd4x_send_command(state, CMD_STOP_MEAS); } static void scd4x_disable_regulator(void *data) { struct scd4x_state *state = data; regulator_disable(state->vdd); } static irqreturn_t scd4x_trigger_handler(int irq, void *p) { struct iio_poll_func *pf = p; struct iio_dev *indio_dev = pf->indio_dev; struct scd4x_state *state = iio_priv(indio_dev); struct { uint16_t data[3]; int64_t ts __aligned(8); } scan; int ret; memset(&scan, 0, sizeof(scan)); mutex_lock(&state->lock); ret = scd4x_read_poll(state, scan.data); mutex_unlock(&state->lock); if (ret) goto out; iio_push_to_buffers_with_timestamp(indio_dev, &scan, iio_get_time_ns(indio_dev)); out: iio_trigger_notify_done(indio_dev->trig); return IRQ_HANDLED; } static int scd4x_probe(struct i2c_client *client, const struct i2c_device_id *id) { static const unsigned long scd4x_scan_masks[] = { 0x07, 0x00 }; struct device *dev = &client->dev; struct iio_dev *indio_dev; struct scd4x_state *state; int ret; indio_dev = devm_iio_device_alloc(dev, sizeof(*state)); if (!indio_dev) return -ENOMEM; state = iio_priv(indio_dev); mutex_init(&state->lock); state->client = client; crc8_populate_msb(scd4x_crc8_table, SCD4X_CRC8_POLYNOMIAL); indio_dev->info = &scd4x_info; indio_dev->name = client->name; indio_dev->channels = scd4x_channels; indio_dev->num_channels = ARRAY_SIZE(scd4x_channels); indio_dev->modes = INDIO_DIRECT_MODE; indio_dev->available_scan_masks = scd4x_scan_masks; state->vdd = devm_regulator_get(dev, "vdd"); if (IS_ERR(state->vdd)) return dev_err_probe(dev, PTR_ERR(state->vdd), "failed to get regulator\n"); ret = regulator_enable(state->vdd); if (ret) return ret; ret = devm_add_action_or_reset(dev, scd4x_disable_regulator, state); if (ret) return ret; ret = scd4x_send_command(state, CMD_STOP_MEAS); if (ret) { dev_err(dev, "failed to stop measurement: %d\n", ret); return ret; } /* execution time */ msleep_interruptible(500); ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL, scd4x_trigger_handler, NULL); if (ret) return ret; ret = scd4x_send_command(state, CMD_START_MEAS); if (ret) { dev_err(dev, "failed to start measurement: %d\n", ret); return ret; } ret = devm_add_action_or_reset(dev, scd4x_stop_meas, state); if (ret) return ret; return devm_iio_device_register(dev, indio_dev); } static const struct of_device_id scd4x_dt_ids[] = { { .compatible = "sensirion,scd40" }, { .compatible = "sensirion,scd41" }, { } }; MODULE_DEVICE_TABLE(of, scd4x_dt_ids); static struct i2c_driver scd4x_i2c_driver = { .driver = { .name = KBUILD_MODNAME, .of_match_table = scd4x_dt_ids, .pm = pm_sleep_ptr(&scd4x_pm_ops), }, .probe = scd4x_probe, }; module_i2c_driver(scd4x_i2c_driver); MODULE_AUTHOR("Roan van Dijk <roan@protonic.nl>"); MODULE_DESCRIPTION("Sensirion SCD4X carbon dioxide sensor core driver"); MODULE_LICENSE("GPL v2"); |