summaryrefslogtreecommitdiffstats
path: root/drivers/iio/pressure/dps310.c
blob: 0730380ceb692e92d8d109972ff2ccfc097b4adf (plain)
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
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
// SPDX-License-Identifier: GPL-2.0+
// Copyright IBM Corp 2019
/*
 * The DPS310 is a barometric pressure and temperature sensor.
 * Currently only reading a single temperature is supported by
 * this driver.
 *
 * https://www.infineon.com/dgdl/?fileId=5546d462576f34750157750826c42242
 *
 * Temperature calculation:
 *   c0 * 0.5 + c1 * T_raw / kT °C
 *
 * TODO:
 *  - Optionally support the FIFO
 */

#include <linux/i2c.h>
#include <linux/limits.h>
#include <linux/math64.h>
#include <linux/module.h>
#include <linux/regmap.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>

#define DPS310_DEV_NAME		"dps310"

#define DPS310_PRS_B0		0x00
#define DPS310_PRS_B1		0x01
#define DPS310_PRS_B2		0x02
#define DPS310_TMP_B0		0x03
#define DPS310_TMP_B1		0x04
#define DPS310_TMP_B2		0x05
#define DPS310_PRS_CFG		0x06
#define  DPS310_PRS_RATE_BITS	GENMASK(6, 4)
#define  DPS310_PRS_PRC_BITS	GENMASK(3, 0)
#define DPS310_TMP_CFG		0x07
#define  DPS310_TMP_RATE_BITS	GENMASK(6, 4)
#define  DPS310_TMP_PRC_BITS	GENMASK(3, 0)
#define  DPS310_TMP_EXT		BIT(7)
#define DPS310_MEAS_CFG		0x08
#define  DPS310_MEAS_CTRL_BITS	GENMASK(2, 0)
#define   DPS310_PRS_EN		BIT(0)
#define   DPS310_TEMP_EN	BIT(1)
#define   DPS310_BACKGROUND	BIT(2)
#define  DPS310_PRS_RDY		BIT(4)
#define  DPS310_TMP_RDY		BIT(5)
#define  DPS310_SENSOR_RDY	BIT(6)
#define  DPS310_COEF_RDY	BIT(7)
#define DPS310_CFG_REG		0x09
#define  DPS310_INT_HL		BIT(7)
#define  DPS310_TMP_SHIFT_EN	BIT(3)
#define  DPS310_PRS_SHIFT_EN	BIT(4)
#define  DPS310_FIFO_EN		BIT(5)
#define  DPS310_SPI_EN		BIT(6)
#define DPS310_RESET		0x0c
#define  DPS310_RESET_MAGIC	0x09
#define DPS310_COEF_BASE	0x10

/* Make sure sleep time is <= 20ms for usleep_range */
#define DPS310_POLL_SLEEP_US(t)		min(20000, (t) / 8)
/* Silently handle error in rate value here */
#define DPS310_POLL_TIMEOUT_US(rc)	((rc) <= 0 ? 1000000 : 1000000 / (rc))

#define DPS310_PRS_BASE		DPS310_PRS_B0
#define DPS310_TMP_BASE		DPS310_TMP_B0

/*
 * These values (defined in the spec) indicate how to scale the raw register
 * values for each level of precision available.
 */
static const int scale_factors[] = {
	 524288,
	1572864,
	3670016,
	7864320,
	 253952,
	 516096,
	1040384,
	2088960,
};

struct dps310_data {
	struct i2c_client *client;
	struct regmap *regmap;
	struct mutex lock;	/* Lock for sequential HW access functions */

	s32 c0, c1;
	s32 c00, c10, c20, c30, c01, c11, c21;
	s32 pressure_raw;
	s32 temp_raw;
};

static const struct iio_chan_spec dps310_channels[] = {
	{
		.type = IIO_TEMP,
		.info_mask_separate = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) |
			BIT(IIO_CHAN_INFO_SAMP_FREQ) |
			BIT(IIO_CHAN_INFO_PROCESSED),
	},
	{
		.type = IIO_PRESSURE,
		.info_mask_separate = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) |
			BIT(IIO_CHAN_INFO_SAMP_FREQ) |
			BIT(IIO_CHAN_INFO_PROCESSED),
	},
};

/* To be called after checking the COEF_RDY bit in MEAS_CFG */
static int dps310_get_coefs(struct dps310_data *data)
{
	int rc;
	u8 coef[18];
	u32 c0, c1;
	u32 c00, c10, c20, c30, c01, c11, c21;

	/* Read all sensor calibration coefficients from the COEF registers. */
	rc = regmap_bulk_read(data->regmap, DPS310_COEF_BASE, coef,
			      sizeof(coef));
	if (rc < 0)
		return rc;

	/*
	 * Calculate temperature calibration coefficients c0 and c1. The
	 * numbers are 12-bit 2's complement numbers.
	 */
	c0 = (coef[0] << 4) | (coef[1] >> 4);
	data->c0 = sign_extend32(c0, 11);

	c1 = ((coef[1] & GENMASK(3, 0)) << 8) | coef[2];
	data->c1 = sign_extend32(c1, 11);

	/*
	 * Calculate pressure calibration coefficients. c00 and c10 are 20 bit
	 * 2's complement numbers, while the rest are 16 bit 2's complement
	 * numbers.
	 */
	c00 = (coef[3] << 12) | (coef[4] << 4) | (coef[5] >> 4);
	data->c00 = sign_extend32(c00, 19);

	c10 = ((coef[5] & GENMASK(3, 0)) << 16) | (coef[6] << 8) | coef[7];
	data->c10 = sign_extend32(c10, 19);

	c01 = (coef[8] << 8) | coef[9];
	data->c01 = sign_extend32(c01, 15);

	c11 = (coef[10] << 8) | coef[11];
	data->c11 = sign_extend32(c11, 15);

	c20 = (coef[12] << 8) | coef[13];
	data->c20 = sign_extend32(c20, 15);

	c21 = (coef[14] << 8) | coef[15];
	data->c21 = sign_extend32(c21, 15);

	c30 = (coef[16] << 8) | coef[17];
	data->c30 = sign_extend32(c30, 15);

	return 0;
}

static int dps310_get_pres_precision(struct dps310_data *data)
{
	int rc;
	int val;

	rc = regmap_read(data->regmap, DPS310_PRS_CFG, &val);
	if (rc < 0)
		return rc;

	return BIT(val & GENMASK(2, 0));
}

static int dps310_get_temp_precision(struct dps310_data *data)
{
	int rc;
	int val;

	rc = regmap_read(data->regmap, DPS310_TMP_CFG, &val);
	if (rc < 0)
		return rc;

	/*
	 * Scale factor is bottom 4 bits of the register, but 1111 is
	 * reserved so just grab bottom three
	 */
	return BIT(val & GENMASK(2, 0));
}

/* Called with lock held */
static int dps310_set_pres_precision(struct dps310_data *data, int val)
{
	int rc;
	u8 shift_en;

	if (val < 0 || val > 128)
		return -EINVAL;

	shift_en = val >= 16 ? DPS310_PRS_SHIFT_EN : 0;
	rc = regmap_write_bits(data->regmap, DPS310_CFG_REG,
			       DPS310_PRS_SHIFT_EN, shift_en);
	if (rc)
		return rc;

	return regmap_update_bits(data->regmap, DPS310_PRS_CFG,
				  DPS310_PRS_PRC_BITS, ilog2(val));
}

/* Called with lock held */
static int dps310_set_temp_precision(struct dps310_data *data, int val)
{
	int rc;
	u8 shift_en;

	if (val < 0 || val > 128)
		return -EINVAL;

	shift_en = val >= 16 ? DPS310_TMP_SHIFT_EN : 0;
	rc = regmap_write_bits(data->regmap, DPS310_CFG_REG,
			       DPS310_TMP_SHIFT_EN, shift_en);
	if (rc)
		return rc;

	return regmap_update_bits(data->regmap, DPS310_TMP_CFG,
				  DPS310_TMP_PRC_BITS, ilog2(val));
}

/* Called with lock held */
static int dps310_set_pres_samp_freq(struct dps310_data *data, int freq)
{
	u8 val;

	if (freq < 0 || freq > 128)
		return -EINVAL;

	val = ilog2(freq) << 4;

	return regmap_update_bits(data->regmap, DPS310_PRS_CFG,
				  DPS310_PRS_RATE_BITS, val);
}

/* Called with lock held */
static int dps310_set_temp_samp_freq(struct dps310_data *data, int freq)
{
	u8 val;

	if (freq < 0 || freq > 128)
		return -EINVAL;

	val = ilog2(freq) << 4;

	return regmap_update_bits(data->regmap, DPS310_TMP_CFG,
				  DPS310_TMP_RATE_BITS, val);
}

static int dps310_get_pres_samp_freq(struct dps310_data *data)
{
	int rc;
	int val;

	rc = regmap_read(data->regmap, DPS310_PRS_CFG, &val);
	if (rc < 0)
		return rc;

	return BIT((val & DPS310_PRS_RATE_BITS) >> 4);
}

static int dps310_get_temp_samp_freq(struct dps310_data *data)
{
	int rc;
	int val;

	rc = regmap_read(data->regmap, DPS310_TMP_CFG, &val);
	if (rc < 0)
		return rc;

	return BIT((val & DPS310_TMP_RATE_BITS) >> 4);
}

static int dps310_get_pres_k(struct dps310_data *data)
{
	int rc = dps310_get_pres_precision(data);

	if (rc < 0)
		return rc;

	return scale_factors[ilog2(rc)];
}

static int dps310_get_temp_k(struct dps310_data *data)
{
	int rc = dps310_get_temp_precision(data);

	if (rc < 0)
		return rc;

	return scale_factors[ilog2(rc)];
}

static int dps310_read_pres_raw(struct dps310_data *data)
{
	int rc;
	int rate;
	int ready;
	int timeout;
	s32 raw;
	u8 val[3];

	if (mutex_lock_interruptible(&data->lock))
		return -EINTR;

	rate = dps310_get_pres_samp_freq(data);
	timeout = DPS310_POLL_TIMEOUT_US(rate);

	/* Poll for sensor readiness; base the timeout upon the sample rate. */
	rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready,
				      ready & DPS310_PRS_RDY,
				      DPS310_POLL_SLEEP_US(timeout), timeout);
	if (rc)
		goto done;

	rc = regmap_bulk_read(data->regmap, DPS310_PRS_BASE, val, sizeof(val));
	if (rc < 0)
		goto done;

	raw = (val[0] << 16) | (val[1] << 8) | val[2];
	data->pressure_raw = sign_extend32(raw, 23);

done:
	mutex_unlock(&data->lock);
	return rc;
}

/* Called with lock held */
static int dps310_read_temp_ready(struct dps310_data *data)
{
	int rc;
	u8 val[3];
	s32 raw;

	rc = regmap_bulk_read(data->regmap, DPS310_TMP_BASE, val, sizeof(val));
	if (rc < 0)
		return rc;

	raw = (val[0] << 16) | (val[1] << 8) | val[2];
	data->temp_raw = sign_extend32(raw, 23);

	return 0;
}

static int dps310_read_temp_raw(struct dps310_data *data)
{
	int rc;
	int rate;
	int ready;
	int timeout;

	if (mutex_lock_interruptible(&data->lock))
		return -EINTR;

	rate = dps310_get_temp_samp_freq(data);
	timeout = DPS310_POLL_TIMEOUT_US(rate);

	/* Poll for sensor readiness; base the timeout upon the sample rate. */
	rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready,
				      ready & DPS310_TMP_RDY,
				      DPS310_POLL_SLEEP_US(timeout), timeout);
	if (rc < 0)
		goto done;

	rc = dps310_read_temp_ready(data);

done:
	mutex_unlock(&data->lock);
	return rc;
}

static bool dps310_is_writeable_reg(struct device *dev, unsigned int reg)
{
	switch (reg) {
	case DPS310_PRS_CFG:
	case DPS310_TMP_CFG:
	case DPS310_MEAS_CFG:
	case DPS310_CFG_REG:
	case DPS310_RESET:
	/* No documentation available on the registers below */
	case 0x0e:
	case 0x0f:
	case 0x62:
		return true;
	default:
		return false;
	}
}

static bool dps310_is_volatile_reg(struct device *dev, unsigned int reg)
{
	switch (reg) {
	case DPS310_PRS_B0:
	case DPS310_PRS_B1:
	case DPS310_PRS_B2:
	case DPS310_TMP_B0:
	case DPS310_TMP_B1:
	case DPS310_TMP_B2:
	case DPS310_MEAS_CFG:
	case 0x32:	/* No documentation available on this register */
		return true;
	default:
		return false;
	}
}

static int dps310_write_raw(struct iio_dev *iio,
			    struct iio_chan_spec const *chan, int val,
			    int val2, long mask)
{
	int rc;
	struct dps310_data *data = iio_priv(iio);

	if (mutex_lock_interruptible(&data->lock))
		return -EINTR;

	switch (mask) {
	case IIO_CHAN_INFO_SAMP_FREQ:
		switch (chan->type) {
		case IIO_PRESSURE:
			rc = dps310_set_pres_samp_freq(data, val);
			break;

		case IIO_TEMP:
			rc = dps310_set_temp_samp_freq(data, val);
			break;

		default:
			rc = -EINVAL;
			break;
		}
		break;

	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
		switch (chan->type) {
		case IIO_PRESSURE:
			rc = dps310_set_pres_precision(data, val);
			break;

		case IIO_TEMP:
			rc = dps310_set_temp_precision(data, val);
			break;

		default:
			rc = -EINVAL;
			break;
		}
		break;

	default:
		rc = -EINVAL;
		break;
	}

	mutex_unlock(&data->lock);
	return rc;
}

static int dps310_calculate_pressure(struct dps310_data *data)
{
	int i;
	int rc;
	int t_ready;
	int kpi = dps310_get_pres_k(data);
	int kti = dps310_get_temp_k(data);
	s64 rem = 0ULL;
	s64 pressure = 0ULL;
	s64 p;
	s64 t;
	s64 denoms[7];
	s64 nums[7];
	s64 rems[7];
	s64 kp;
	s64 kt;

	if (kpi < 0)
		return kpi;

	if (kti < 0)
		return kti;

	kp = (s64)kpi;
	kt = (s64)kti;

	/* Refresh temp if it's ready, otherwise just use the latest value */
	if (mutex_trylock(&data->lock)) {
		rc = regmap_read(data->regmap, DPS310_MEAS_CFG, &t_ready);
		if (rc >= 0 && t_ready & DPS310_TMP_RDY)
			dps310_read_temp_ready(data);

		mutex_unlock(&data->lock);
	}

	p = (s64)data->pressure_raw;
	t = (s64)data->temp_raw;

	/* Section 4.9.1 of the DPS310 spec; algebra'd to avoid underflow */
	nums[0] = (s64)data->c00;
	denoms[0] = 1LL;
	nums[1] = p * (s64)data->c10;
	denoms[1] = kp;
	nums[2] = p * p * (s64)data->c20;
	denoms[2] = kp * kp;
	nums[3] = p * p * p * (s64)data->c30;
	denoms[3] = kp * kp * kp;
	nums[4] = t * (s64)data->c01;
	denoms[4] = kt;
	nums[5] = t * p * (s64)data->c11;
	denoms[5] = kp * kt;
	nums[6] = t * p * p * (s64)data->c21;
	denoms[6] = kp * kp * kt;

	/* Kernel lacks a div64_s64_rem function; denoms are all positive */
	for (i = 0; i < 7; ++i) {
		u64 irem;

		if (nums[i] < 0LL) {
			pressure -= div64_u64_rem(-nums[i], denoms[i], &irem);
			rems[i] = -irem;
		} else {
			pressure += div64_u64_rem(nums[i], denoms[i], &irem);
			rems[i] = (s64)irem;
		}
	}

	/* Increase precision and calculate the remainder sum */
	for (i = 0; i < 7; ++i)
		rem += div64_s64((s64)rems[i] * 1000000000LL, denoms[i]);

	pressure += div_s64(rem, 1000000000LL);
	if (pressure < 0LL)
		return -ERANGE;

	return (int)min_t(s64, pressure, INT_MAX);
}

static int dps310_read_pressure(struct dps310_data *data, int *val, int *val2,
				long mask)
{
	int rc;

	switch (mask) {
	case IIO_CHAN_INFO_SAMP_FREQ:
		rc = dps310_get_pres_samp_freq(data);
		if (rc < 0)
			return rc;

		*val = rc;
		return IIO_VAL_INT;

	case IIO_CHAN_INFO_PROCESSED:
		rc = dps310_read_pres_raw(data);
		if (rc)
			return rc;

		rc = dps310_calculate_pressure(data);
		if (rc < 0)
			return rc;

		*val = rc;
		*val2 = 1000; /* Convert Pa to KPa per IIO ABI */
		return IIO_VAL_FRACTIONAL;

	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
		rc = dps310_get_pres_precision(data);
		if (rc < 0)
			return rc;

		*val = rc;
		return IIO_VAL_INT;

	default:
		return -EINVAL;
	}
}

static int dps310_calculate_temp(struct dps310_data *data)
{
	s64 c0;
	s64 t;
	int kt = dps310_get_temp_k(data);

	if (kt < 0)
		return kt;

	/* Obtain inverse-scaled offset */
	c0 = div_s64((s64)kt * (s64)data->c0, 2);

	/* Add the offset to the unscaled temperature */
	t = c0 + ((s64)data->temp_raw * (s64)data->c1);

	/* Convert to milliCelsius and scale the temperature */
	return (int)div_s64(t * 1000LL, kt);
}

static int dps310_read_temp(struct dps310_data *data, int *val, int *val2,
			    long mask)
{
	int rc;

	switch (mask) {
	case IIO_CHAN_INFO_SAMP_FREQ:
		rc = dps310_get_temp_samp_freq(data);
		if (rc < 0)
			return rc;

		*val = rc;
		return IIO_VAL_INT;

	case IIO_CHAN_INFO_PROCESSED:
		rc = dps310_read_temp_raw(data);
		if (rc)
			return rc;

		rc = dps310_calculate_temp(data);
		if (rc < 0)
			return rc;

		*val = rc;
		return IIO_VAL_INT;

	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
		rc = dps310_get_temp_precision(data);
		if (rc < 0)
			return rc;

		*val = rc;
		return IIO_VAL_INT;

	default:
		return -EINVAL;
	}
}

static int dps310_read_raw(struct iio_dev *iio,
			   struct iio_chan_spec const *chan,
			   int *val, int *val2, long mask)
{
	struct dps310_data *data = iio_priv(iio);

	switch (chan->type) {
	case IIO_PRESSURE:
		return dps310_read_pressure(data, val, val2, mask);

	case IIO_TEMP:
		return dps310_read_temp(data, val, val2, mask);

	default:
		return -EINVAL;
	}
}

static void dps310_reset(void *action_data)
{
	struct dps310_data *data = action_data;

	regmap_write(data->regmap, DPS310_RESET, DPS310_RESET_MAGIC);
}

static const struct regmap_config dps310_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.writeable_reg = dps310_is_writeable_reg,
	.volatile_reg = dps310_is_volatile_reg,
	.cache_type = REGCACHE_RBTREE,
	.max_register = 0x62, /* No documentation available on this register */
};

static const struct iio_info dps310_info = {
	.read_raw = dps310_read_raw,
	.write_raw = dps310_write_raw,
};

/*
 * Some verions of chip will read temperatures in the ~60C range when
 * its actually ~20C. This is the manufacturer recommended workaround
 * to correct the issue. The registers used below are undocumented.
 */
static int dps310_temp_workaround(struct dps310_data *data)
{
	int rc;
	int reg;

	rc = regmap_read(data->regmap, 0x32, &reg);
	if (rc < 0)
		return rc;

	/*
	 * If bit 1 is set then the device is okay, and the workaround does not
	 * need to be applied
	 */
	if (reg & BIT(1))
		return 0;

	rc = regmap_write(data->regmap, 0x0e, 0xA5);
	if (rc < 0)
		return rc;

	rc = regmap_write(data->regmap, 0x0f, 0x96);
	if (rc < 0)
		return rc;

	rc = regmap_write(data->regmap, 0x62, 0x02);
	if (rc < 0)
		return rc;

	rc = regmap_write(data->regmap, 0x0e, 0x00);
	if (rc < 0)
		return rc;

	return regmap_write(data->regmap, 0x0f, 0x00);
}

static int dps310_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct dps310_data *data;
	struct iio_dev *iio;
	int rc, ready;

	iio = devm_iio_device_alloc(&client->dev,  sizeof(*data));
	if (!iio)
		return -ENOMEM;

	data = iio_priv(iio);
	data->client = client;
	mutex_init(&data->lock);

	iio->name = id->name;
	iio->channels = dps310_channels;
	iio->num_channels = ARRAY_SIZE(dps310_channels);
	iio->info = &dps310_info;
	iio->modes = INDIO_DIRECT_MODE;

	data->regmap = devm_regmap_init_i2c(client, &dps310_regmap_config);
	if (IS_ERR(data->regmap))
		return PTR_ERR(data->regmap);

	/* Register to run the device reset when the device is removed */
	rc = devm_add_action_or_reset(&client->dev, dps310_reset, data);
	if (rc)
		return rc;

	/*
	 * Set up pressure sensor in single sample, one measurement per second
	 * mode
	 */
	rc = regmap_write(data->regmap, DPS310_PRS_CFG, 0);

	/*
	 * Set up external (MEMS) temperature sensor in single sample, one
	 * measurement per second mode
	 */
	rc = regmap_write(data->regmap, DPS310_TMP_CFG, DPS310_TMP_EXT);
	if (rc < 0)
		return rc;

	/* Temp and pressure shifts are disabled when PRC <= 8 */
	rc = regmap_write_bits(data->regmap, DPS310_CFG_REG,
			       DPS310_PRS_SHIFT_EN | DPS310_TMP_SHIFT_EN, 0);
	if (rc < 0)
		return rc;

	/* MEAS_CFG doesn't update correctly unless first written with 0 */
	rc = regmap_write_bits(data->regmap, DPS310_MEAS_CFG,
			       DPS310_MEAS_CTRL_BITS, 0);
	if (rc < 0)
		return rc;

	/* Turn on temperature and pressure measurement in the background */
	rc = regmap_write_bits(data->regmap, DPS310_MEAS_CFG,
			       DPS310_MEAS_CTRL_BITS, DPS310_PRS_EN |
			       DPS310_TEMP_EN | DPS310_BACKGROUND);
	if (rc < 0)
		return rc;

	/*
	 * Calibration coefficients required for reporting temperature.
	 * They are available 40ms after the device has started
	 */
	rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready,
				      ready & DPS310_COEF_RDY, 10000, 40000);
	if (rc < 0)
		return rc;

	rc = dps310_get_coefs(data);
	if (rc < 0)
		return rc;

	rc = dps310_temp_workaround(data);
	if (rc < 0)
		return rc;

	rc = devm_iio_device_register(&client->dev, iio);
	if (rc)
		return rc;

	i2c_set_clientdata(client, iio);

	return 0;
}

static const struct i2c_device_id dps310_id[] = {
	{ DPS310_DEV_NAME, 0 },
	{}
};
MODULE_DEVICE_TABLE(i2c, dps310_id);

static struct i2c_driver dps310_driver = {
	.driver = {
		.name = DPS310_DEV_NAME,
	},
	.probe = dps310_probe,
	.id_table = dps310_id,
};
module_i2c_driver(dps310_driver);

MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>");
MODULE_DESCRIPTION("Infineon DPS310 pressure and temperature sensor");
MODULE_LICENSE("GPL v2");