1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Sensirion SCD4X carbon dioxide sensor i2c driver
4 *
5 * Copyright (C) 2021 Protonic Holland
6 * Author: Roan van Dijk <roan@protonic.nl>
7 *
8 * I2C slave address: 0x62
9 *
10 * Datasheets:
11 * https://www.sensirion.com/file/datasheet_scd4x
12 */
13
14 #include <asm/unaligned.h>
15 #include <linux/crc8.h>
16 #include <linux/delay.h>
17 #include <linux/device.h>
18 #include <linux/i2c.h>
19 #include <linux/iio/buffer.h>
20 #include <linux/iio/iio.h>
21 #include <linux/iio/sysfs.h>
22 #include <linux/iio/trigger.h>
23 #include <linux/iio/trigger_consumer.h>
24 #include <linux/iio/triggered_buffer.h>
25 #include <linux/iio/types.h>
26 #include <linux/kernel.h>
27 #include <linux/mutex.h>
28 #include <linux/string.h>
29 #include <linux/sysfs.h>
30 #include <linux/types.h>
31
32 #define SCD4X_CRC8_POLYNOMIAL 0x31
33 #define SCD4X_TIMEOUT_ERR 1000
34 #define SCD4X_READ_BUF_SIZE 9
35 #define SCD4X_COMMAND_BUF_SIZE 2
36 #define SCD4X_WRITE_BUF_SIZE 5
37 #define SCD4X_FRC_MIN_PPM 0
38 #define SCD4X_FRC_MAX_PPM 2000
39 #define SCD4X_PRESSURE_COMP_MIN_MBAR 700
40 #define SCD4X_PRESSURE_COMP_MAX_MBAR 1200
41 #define SCD4X_READY_MASK 0x01
42
43 /*Commands SCD4X*/
44 enum scd4x_cmd {
45 CMD_START_MEAS = 0x21b1,
46 CMD_READ_MEAS = 0xec05,
47 CMD_STOP_MEAS = 0x3f86,
48 CMD_SET_TEMP_OFFSET = 0x241d,
49 CMD_GET_TEMP_OFFSET = 0x2318,
50 CMD_SET_AMB_PRESSURE = 0xe000,
51 CMD_GET_AMB_PRESSURE = 0xe000,
52 CMD_FRC = 0x362f,
53 CMD_SET_ASC = 0x2416,
54 CMD_GET_ASC = 0x2313,
55 CMD_GET_DATA_READY = 0xe4b8,
56 };
57
58 enum scd4x_channel_idx {
59 SCD4X_CO2,
60 SCD4X_TEMP,
61 SCD4X_HR,
62 };
63
64 struct scd4x_state {
65 struct i2c_client *client;
66 /* maintain access to device, to prevent concurrent reads/writes */
67 struct mutex lock;
68 struct regulator *vdd;
69 };
70
71 DECLARE_CRC8_TABLE(scd4x_crc8_table);
72
scd4x_i2c_xfer(struct scd4x_state * state,char * txbuf,int txsize,char * rxbuf,int rxsize)73 static int scd4x_i2c_xfer(struct scd4x_state *state, char *txbuf, int txsize,
74 char *rxbuf, int rxsize)
75 {
76 struct i2c_client *client = state->client;
77 int ret;
78
79 ret = i2c_master_send(client, txbuf, txsize);
80
81 if (ret < 0)
82 return ret;
83 if (ret != txsize)
84 return -EIO;
85
86 if (rxsize == 0)
87 return 0;
88
89 ret = i2c_master_recv(client, rxbuf, rxsize);
90 if (ret < 0)
91 return ret;
92 if (ret != rxsize)
93 return -EIO;
94
95 return 0;
96 }
97
scd4x_send_command(struct scd4x_state * state,enum scd4x_cmd cmd)98 static int scd4x_send_command(struct scd4x_state *state, enum scd4x_cmd cmd)
99 {
100 char buf[SCD4X_COMMAND_BUF_SIZE];
101 int ret;
102
103 /*
104 * Measurement needs to be stopped before sending commands.
105 * Except stop and start command.
106 */
107 if ((cmd != CMD_STOP_MEAS) && (cmd != CMD_START_MEAS)) {
108
109 ret = scd4x_send_command(state, CMD_STOP_MEAS);
110 if (ret)
111 return ret;
112
113 /* execution time for stopping measurement */
114 msleep_interruptible(500);
115 }
116
117 put_unaligned_be16(cmd, buf);
118 ret = scd4x_i2c_xfer(state, buf, 2, buf, 0);
119 if (ret)
120 return ret;
121
122 if ((cmd != CMD_STOP_MEAS) && (cmd != CMD_START_MEAS)) {
123 ret = scd4x_send_command(state, CMD_START_MEAS);
124 if (ret)
125 return ret;
126 }
127
128 return 0;
129 }
130
scd4x_read(struct scd4x_state * state,enum scd4x_cmd cmd,void * response,int response_sz)131 static int scd4x_read(struct scd4x_state *state, enum scd4x_cmd cmd,
132 void *response, int response_sz)
133 {
134 struct i2c_client *client = state->client;
135 char buf[SCD4X_READ_BUF_SIZE];
136 char *rsp = response;
137 int i, ret;
138 char crc;
139
140 /*
141 * Measurement needs to be stopped before sending commands.
142 * Except for reading measurement and data ready command.
143 */
144 if ((cmd != CMD_GET_DATA_READY) && (cmd != CMD_READ_MEAS) &&
145 (cmd != CMD_GET_AMB_PRESSURE)) {
146 ret = scd4x_send_command(state, CMD_STOP_MEAS);
147 if (ret)
148 return ret;
149
150 /* execution time for stopping measurement */
151 msleep_interruptible(500);
152 }
153
154 /* CRC byte for every 2 bytes of data */
155 response_sz += response_sz / 2;
156
157 put_unaligned_be16(cmd, buf);
158 ret = scd4x_i2c_xfer(state, buf, 2, buf, response_sz);
159 if (ret)
160 return ret;
161
162 for (i = 0; i < response_sz; i += 3) {
163 crc = crc8(scd4x_crc8_table, buf + i, 2, CRC8_INIT_VALUE);
164 if (crc != buf[i + 2]) {
165 dev_err(&client->dev, "CRC error\n");
166 return -EIO;
167 }
168
169 *rsp++ = buf[i];
170 *rsp++ = buf[i + 1];
171 }
172
173 /* start measurement */
174 if ((cmd != CMD_GET_DATA_READY) && (cmd != CMD_READ_MEAS) &&
175 (cmd != CMD_GET_AMB_PRESSURE)) {
176 ret = scd4x_send_command(state, CMD_START_MEAS);
177 if (ret)
178 return ret;
179 }
180
181 return 0;
182 }
183
scd4x_write(struct scd4x_state * state,enum scd4x_cmd cmd,uint16_t arg)184 static int scd4x_write(struct scd4x_state *state, enum scd4x_cmd cmd, uint16_t arg)
185 {
186 char buf[SCD4X_WRITE_BUF_SIZE];
187 int ret;
188 char crc;
189
190 put_unaligned_be16(cmd, buf);
191 put_unaligned_be16(arg, buf + 2);
192
193 crc = crc8(scd4x_crc8_table, buf + 2, 2, CRC8_INIT_VALUE);
194 buf[4] = crc;
195
196 /* measurement needs to be stopped before sending commands */
197 if (cmd != CMD_SET_AMB_PRESSURE) {
198 ret = scd4x_send_command(state, CMD_STOP_MEAS);
199 if (ret)
200 return ret;
201 }
202
203 /* execution time */
204 msleep_interruptible(500);
205
206 ret = scd4x_i2c_xfer(state, buf, SCD4X_WRITE_BUF_SIZE, buf, 0);
207 if (ret)
208 return ret;
209
210 /* start measurement, except for forced calibration command */
211 if ((cmd != CMD_FRC) && (cmd != CMD_SET_AMB_PRESSURE)) {
212 ret = scd4x_send_command(state, CMD_START_MEAS);
213 if (ret)
214 return ret;
215 }
216
217 return 0;
218 }
219
scd4x_write_and_fetch(struct scd4x_state * state,enum scd4x_cmd cmd,uint16_t arg,void * response,int response_sz)220 static int scd4x_write_and_fetch(struct scd4x_state *state, enum scd4x_cmd cmd,
221 uint16_t arg, void *response, int response_sz)
222 {
223 struct i2c_client *client = state->client;
224 char buf[SCD4X_READ_BUF_SIZE];
225 char *rsp = response;
226 int i, ret;
227 char crc;
228
229 ret = scd4x_write(state, CMD_FRC, arg);
230 if (ret)
231 goto err;
232
233 /* execution time */
234 msleep_interruptible(400);
235
236 /* CRC byte for every 2 bytes of data */
237 response_sz += response_sz / 2;
238
239 ret = i2c_master_recv(client, buf, response_sz);
240 if (ret < 0)
241 goto err;
242 if (ret != response_sz) {
243 ret = -EIO;
244 goto err;
245 }
246
247 for (i = 0; i < response_sz; i += 3) {
248 crc = crc8(scd4x_crc8_table, buf + i, 2, CRC8_INIT_VALUE);
249 if (crc != buf[i + 2]) {
250 dev_err(&client->dev, "CRC error\n");
251 ret = -EIO;
252 goto err;
253 }
254
255 *rsp++ = buf[i];
256 *rsp++ = buf[i + 1];
257 }
258
259 return scd4x_send_command(state, CMD_START_MEAS);
260
261 err:
262 /*
263 * on error try to start the measurement,
264 * puts sensor back into continuous measurement
265 */
266 scd4x_send_command(state, CMD_START_MEAS);
267
268 return ret;
269 }
270
scd4x_read_meas(struct scd4x_state * state,uint16_t * meas)271 static int scd4x_read_meas(struct scd4x_state *state, uint16_t *meas)
272 {
273 int i, ret;
274 __be16 buf[3];
275
276 ret = scd4x_read(state, CMD_READ_MEAS, buf, sizeof(buf));
277 if (ret)
278 return ret;
279
280 for (i = 0; i < ARRAY_SIZE(buf); i++)
281 meas[i] = be16_to_cpu(buf[i]);
282
283 return 0;
284 }
285
scd4x_wait_meas_poll(struct scd4x_state * state)286 static int scd4x_wait_meas_poll(struct scd4x_state *state)
287 {
288 struct i2c_client *client = state->client;
289 int tries = 6;
290 int ret;
291
292 do {
293 __be16 bval;
294 uint16_t val;
295
296 ret = scd4x_read(state, CMD_GET_DATA_READY, &bval, sizeof(bval));
297 if (ret)
298 return -EIO;
299 val = be16_to_cpu(bval);
300
301 /* new measurement available */
302 if (val & 0x7FF)
303 return 0;
304
305 msleep_interruptible(1000);
306 } while (--tries);
307
308 /* try to start sensor on timeout */
309 ret = scd4x_send_command(state, CMD_START_MEAS);
310 if (ret)
311 dev_err(&client->dev, "failed to start measurement: %d\n", ret);
312
313 return -ETIMEDOUT;
314 }
315
scd4x_read_poll(struct scd4x_state * state,uint16_t * buf)316 static int scd4x_read_poll(struct scd4x_state *state, uint16_t *buf)
317 {
318 int ret;
319
320 ret = scd4x_wait_meas_poll(state);
321 if (ret)
322 return ret;
323
324 return scd4x_read_meas(state, buf);
325 }
326
scd4x_read_channel(struct scd4x_state * state,int chan)327 static int scd4x_read_channel(struct scd4x_state *state, int chan)
328 {
329 int ret;
330 uint16_t buf[3];
331
332 ret = scd4x_read_poll(state, buf);
333 if (ret)
334 return ret;
335
336 return buf[chan];
337 }
338
scd4x_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)339 static int scd4x_read_raw(struct iio_dev *indio_dev,
340 struct iio_chan_spec const *chan, int *val,
341 int *val2, long mask)
342 {
343 struct scd4x_state *state = iio_priv(indio_dev);
344 int ret;
345 __be16 tmp;
346
347 switch (mask) {
348 case IIO_CHAN_INFO_RAW:
349 if (chan->output) {
350 mutex_lock(&state->lock);
351 ret = scd4x_read(state, CMD_GET_AMB_PRESSURE, &tmp, sizeof(tmp));
352 mutex_unlock(&state->lock);
353
354 if (ret)
355 return ret;
356
357 *val = be16_to_cpu(tmp);
358 return IIO_VAL_INT;
359 }
360
361 ret = iio_device_claim_direct_mode(indio_dev);
362 if (ret)
363 return ret;
364
365 mutex_lock(&state->lock);
366 ret = scd4x_read_channel(state, chan->address);
367 mutex_unlock(&state->lock);
368
369 iio_device_release_direct_mode(indio_dev);
370 if (ret < 0)
371 return ret;
372
373 *val = ret;
374 return IIO_VAL_INT;
375 case IIO_CHAN_INFO_SCALE:
376 if (chan->type == IIO_CONCENTRATION) {
377 *val = 0;
378 *val2 = 100;
379 return IIO_VAL_INT_PLUS_MICRO;
380 } else if (chan->type == IIO_TEMP) {
381 *val = 175000;
382 *val2 = 65536;
383 return IIO_VAL_FRACTIONAL;
384 } else if (chan->type == IIO_HUMIDITYRELATIVE) {
385 *val = 100000;
386 *val2 = 65536;
387 return IIO_VAL_FRACTIONAL;
388 }
389 return -EINVAL;
390 case IIO_CHAN_INFO_OFFSET:
391 *val = -16852;
392 *val2 = 114286;
393 return IIO_VAL_INT_PLUS_MICRO;
394 case IIO_CHAN_INFO_CALIBBIAS:
395 mutex_lock(&state->lock);
396 ret = scd4x_read(state, CMD_GET_TEMP_OFFSET, &tmp, sizeof(tmp));
397 mutex_unlock(&state->lock);
398 if (ret)
399 return ret;
400
401 *val = be16_to_cpu(tmp);
402
403 return IIO_VAL_INT;
404 default:
405 return -EINVAL;
406 }
407 }
408
409 static const int scd4x_pressure_calibbias_available[] = {
410 SCD4X_PRESSURE_COMP_MIN_MBAR, 1, SCD4X_PRESSURE_COMP_MAX_MBAR,
411 };
412
scd4x_read_avail(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,const int ** vals,int * type,int * length,long mask)413 static int scd4x_read_avail(struct iio_dev *indio_dev, struct iio_chan_spec const *chan,
414 const int **vals, int *type, int *length, long mask)
415 {
416 switch (mask) {
417 case IIO_CHAN_INFO_RAW:
418 *vals = scd4x_pressure_calibbias_available;
419 *type = IIO_VAL_INT;
420
421 return IIO_AVAIL_RANGE;
422 }
423
424 return -EINVAL;
425 }
426
427
scd4x_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)428 static int scd4x_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan,
429 int val, int val2, long mask)
430 {
431 struct scd4x_state *state = iio_priv(indio_dev);
432 int ret = 0;
433
434 switch (mask) {
435 case IIO_CHAN_INFO_CALIBBIAS:
436 mutex_lock(&state->lock);
437 ret = scd4x_write(state, CMD_SET_TEMP_OFFSET, val);
438 mutex_unlock(&state->lock);
439
440 return ret;
441 case IIO_CHAN_INFO_RAW:
442 switch (chan->type) {
443 case IIO_PRESSURE:
444 if (val < SCD4X_PRESSURE_COMP_MIN_MBAR ||
445 val > SCD4X_PRESSURE_COMP_MAX_MBAR)
446 return -EINVAL;
447
448 mutex_lock(&state->lock);
449 ret = scd4x_write(state, CMD_SET_AMB_PRESSURE, val);
450 mutex_unlock(&state->lock);
451
452 return ret;
453 default:
454 return -EINVAL;
455 }
456 default:
457 return -EINVAL;
458 }
459 }
460
calibration_auto_enable_show(struct device * dev,struct device_attribute * attr,char * buf)461 static ssize_t calibration_auto_enable_show(struct device *dev,
462 struct device_attribute *attr, char *buf)
463 {
464 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
465 struct scd4x_state *state = iio_priv(indio_dev);
466 int ret;
467 __be16 bval;
468 u16 val;
469
470 mutex_lock(&state->lock);
471 ret = scd4x_read(state, CMD_GET_ASC, &bval, sizeof(bval));
472 mutex_unlock(&state->lock);
473 if (ret) {
474 dev_err(dev, "failed to read automatic calibration");
475 return ret;
476 }
477
478 val = (be16_to_cpu(bval) & SCD4X_READY_MASK) ? 1 : 0;
479
480 return sysfs_emit(buf, "%d\n", val);
481 }
482
calibration_auto_enable_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)483 static ssize_t calibration_auto_enable_store(struct device *dev,
484 struct device_attribute *attr,
485 const char *buf, size_t len)
486 {
487 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
488 struct scd4x_state *state = iio_priv(indio_dev);
489 bool val;
490 int ret;
491 uint16_t value;
492
493 ret = kstrtobool(buf, &val);
494 if (ret)
495 return ret;
496
497 value = val;
498
499 mutex_lock(&state->lock);
500 ret = scd4x_write(state, CMD_SET_ASC, value);
501 mutex_unlock(&state->lock);
502 if (ret)
503 dev_err(dev, "failed to set automatic calibration");
504
505 return ret ?: len;
506 }
507
calibration_forced_value_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)508 static ssize_t calibration_forced_value_store(struct device *dev,
509 struct device_attribute *attr,
510 const char *buf, size_t len)
511 {
512 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
513 struct scd4x_state *state = iio_priv(indio_dev);
514 uint16_t val, arg;
515 int ret;
516
517 ret = kstrtou16(buf, 0, &arg);
518 if (ret)
519 return ret;
520
521 if (arg < SCD4X_FRC_MIN_PPM || arg > SCD4X_FRC_MAX_PPM)
522 return -EINVAL;
523
524 mutex_lock(&state->lock);
525 ret = scd4x_write_and_fetch(state, CMD_FRC, arg, &val, sizeof(val));
526 mutex_unlock(&state->lock);
527
528 if (ret)
529 return ret;
530
531 if (val == 0xff) {
532 dev_err(dev, "forced calibration has failed");
533 return -EINVAL;
534 }
535
536 return len;
537 }
538
539 static IIO_DEVICE_ATTR_RW(calibration_auto_enable, 0);
540 static IIO_DEVICE_ATTR_WO(calibration_forced_value, 0);
541
542 static IIO_CONST_ATTR(calibration_forced_value_available,
543 __stringify([SCD4X_FRC_MIN_PPM 1 SCD4X_FRC_MAX_PPM]));
544
545 static struct attribute *scd4x_attrs[] = {
546 &iio_dev_attr_calibration_auto_enable.dev_attr.attr,
547 &iio_dev_attr_calibration_forced_value.dev_attr.attr,
548 &iio_const_attr_calibration_forced_value_available.dev_attr.attr,
549 NULL
550 };
551
552 static const struct attribute_group scd4x_attr_group = {
553 .attrs = scd4x_attrs,
554 };
555
556 static const struct iio_info scd4x_info = {
557 .attrs = &scd4x_attr_group,
558 .read_raw = scd4x_read_raw,
559 .write_raw = scd4x_write_raw,
560 .read_avail = scd4x_read_avail,
561 };
562
563 static const struct iio_chan_spec scd4x_channels[] = {
564 {
565 /*
566 * this channel is special in a sense we are pretending that
567 * sensor is able to change measurement chamber pressure but in
568 * fact we're just setting pressure compensation value
569 */
570 .type = IIO_PRESSURE,
571 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
572 .info_mask_separate_available = BIT(IIO_CHAN_INFO_RAW),
573 .output = 1,
574 .scan_index = -1,
575 },
576 {
577 .type = IIO_CONCENTRATION,
578 .channel2 = IIO_MOD_CO2,
579 .modified = 1,
580 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
581 BIT(IIO_CHAN_INFO_SCALE),
582 .address = SCD4X_CO2,
583 .scan_index = SCD4X_CO2,
584 .scan_type = {
585 .sign = 'u',
586 .realbits = 16,
587 .storagebits = 16,
588 .endianness = IIO_BE,
589 },
590 },
591 {
592 .type = IIO_TEMP,
593 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
594 BIT(IIO_CHAN_INFO_SCALE) |
595 BIT(IIO_CHAN_INFO_OFFSET) |
596 BIT(IIO_CHAN_INFO_CALIBBIAS),
597 .address = SCD4X_TEMP,
598 .scan_index = SCD4X_TEMP,
599 .scan_type = {
600 .sign = 'u',
601 .realbits = 16,
602 .storagebits = 16,
603 .endianness = IIO_BE,
604 },
605 },
606 {
607 .type = IIO_HUMIDITYRELATIVE,
608 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
609 BIT(IIO_CHAN_INFO_SCALE),
610 .address = SCD4X_HR,
611 .scan_index = SCD4X_HR,
612 .scan_type = {
613 .sign = 'u',
614 .realbits = 16,
615 .storagebits = 16,
616 .endianness = IIO_BE,
617 },
618 },
619 };
620
scd4x_suspend(struct device * dev)621 static int scd4x_suspend(struct device *dev)
622 {
623 struct iio_dev *indio_dev = dev_get_drvdata(dev);
624 struct scd4x_state *state = iio_priv(indio_dev);
625 int ret;
626
627 ret = scd4x_send_command(state, CMD_STOP_MEAS);
628 if (ret)
629 return ret;
630
631 return regulator_disable(state->vdd);
632 }
633
scd4x_resume(struct device * dev)634 static int scd4x_resume(struct device *dev)
635 {
636 struct iio_dev *indio_dev = dev_get_drvdata(dev);
637 struct scd4x_state *state = iio_priv(indio_dev);
638 int ret;
639
640 ret = regulator_enable(state->vdd);
641 if (ret)
642 return ret;
643
644 return scd4x_send_command(state, CMD_START_MEAS);
645 }
646
647 static DEFINE_SIMPLE_DEV_PM_OPS(scd4x_pm_ops, scd4x_suspend, scd4x_resume);
648
scd4x_stop_meas(void * state)649 static void scd4x_stop_meas(void *state)
650 {
651 scd4x_send_command(state, CMD_STOP_MEAS);
652 }
653
scd4x_disable_regulator(void * data)654 static void scd4x_disable_regulator(void *data)
655 {
656 struct scd4x_state *state = data;
657
658 regulator_disable(state->vdd);
659 }
660
scd4x_trigger_handler(int irq,void * p)661 static irqreturn_t scd4x_trigger_handler(int irq, void *p)
662 {
663 struct iio_poll_func *pf = p;
664 struct iio_dev *indio_dev = pf->indio_dev;
665 struct scd4x_state *state = iio_priv(indio_dev);
666 struct {
667 uint16_t data[3];
668 int64_t ts __aligned(8);
669 } scan;
670 int ret;
671
672 memset(&scan, 0, sizeof(scan));
673 mutex_lock(&state->lock);
674 ret = scd4x_read_poll(state, scan.data);
675 mutex_unlock(&state->lock);
676 if (ret)
677 goto out;
678
679 iio_push_to_buffers_with_timestamp(indio_dev, &scan, iio_get_time_ns(indio_dev));
680 out:
681 iio_trigger_notify_done(indio_dev->trig);
682 return IRQ_HANDLED;
683 }
684
scd4x_probe(struct i2c_client * client)685 static int scd4x_probe(struct i2c_client *client)
686 {
687 static const unsigned long scd4x_scan_masks[] = { 0x07, 0x00 };
688 struct device *dev = &client->dev;
689 struct iio_dev *indio_dev;
690 struct scd4x_state *state;
691 int ret;
692
693 indio_dev = devm_iio_device_alloc(dev, sizeof(*state));
694 if (!indio_dev)
695 return -ENOMEM;
696
697 state = iio_priv(indio_dev);
698 mutex_init(&state->lock);
699 state->client = client;
700 crc8_populate_msb(scd4x_crc8_table, SCD4X_CRC8_POLYNOMIAL);
701
702 indio_dev->info = &scd4x_info;
703 indio_dev->name = client->name;
704 indio_dev->channels = scd4x_channels;
705 indio_dev->num_channels = ARRAY_SIZE(scd4x_channels);
706 indio_dev->modes = INDIO_DIRECT_MODE;
707 indio_dev->available_scan_masks = scd4x_scan_masks;
708
709 state->vdd = devm_regulator_get(dev, "vdd");
710 if (IS_ERR(state->vdd))
711 return dev_err_probe(dev, PTR_ERR(state->vdd), "failed to get regulator\n");
712
713 ret = regulator_enable(state->vdd);
714 if (ret)
715 return ret;
716
717 ret = devm_add_action_or_reset(dev, scd4x_disable_regulator, state);
718 if (ret)
719 return ret;
720
721 ret = scd4x_send_command(state, CMD_STOP_MEAS);
722 if (ret) {
723 dev_err(dev, "failed to stop measurement: %d\n", ret);
724 return ret;
725 }
726
727 /* execution time */
728 msleep_interruptible(500);
729
730 ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL, scd4x_trigger_handler, NULL);
731 if (ret)
732 return ret;
733
734 ret = scd4x_send_command(state, CMD_START_MEAS);
735 if (ret) {
736 dev_err(dev, "failed to start measurement: %d\n", ret);
737 return ret;
738 }
739
740 ret = devm_add_action_or_reset(dev, scd4x_stop_meas, state);
741 if (ret)
742 return ret;
743
744 return devm_iio_device_register(dev, indio_dev);
745 }
746
747 static const struct of_device_id scd4x_dt_ids[] = {
748 { .compatible = "sensirion,scd40" },
749 { .compatible = "sensirion,scd41" },
750 { }
751 };
752 MODULE_DEVICE_TABLE(of, scd4x_dt_ids);
753
754 static struct i2c_driver scd4x_i2c_driver = {
755 .driver = {
756 .name = KBUILD_MODNAME,
757 .of_match_table = scd4x_dt_ids,
758 .pm = pm_sleep_ptr(&scd4x_pm_ops),
759 },
760 .probe = scd4x_probe,
761 };
762 module_i2c_driver(scd4x_i2c_driver);
763
764 MODULE_AUTHOR("Roan van Dijk <roan@protonic.nl>");
765 MODULE_DESCRIPTION("Sensirion SCD4X carbon dioxide sensor core driver");
766 MODULE_LICENSE("GPL v2");
767