summaryrefslogtreecommitdiffstats
path: root/drivers/iio/accel/mma8452.c
blob: 13ea1ea23328501f4969c5453e603cf67e5b81b2 (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
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
/*
 * mma8452.c - Support for Freescale MMA8452Q 3-axis 12-bit accelerometer
 *
 * Copyright 2014 Peter Meerwald <pmeerw@pmeerw.net>
 *
 * This file is subject to the terms and conditions of version 2 of
 * the GNU General Public License.  See the file COPYING in the main
 * directory of this archive for more details.
 *
 * 7-bit I2C slave address 0x1c/0x1d (pin selectable)
 *
 * TODO: orientation / freefall events, autosleep
 */

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/events.h>
#include <linux/delay.h>

#define MMA8452_STATUS 0x00
#define MMA8452_OUT_X 0x01 /* MSB first, 12-bit  */
#define MMA8452_OUT_Y 0x03
#define MMA8452_OUT_Z 0x05
#define MMA8452_INT_SRC 0x0c
#define MMA8452_WHO_AM_I 0x0d
#define MMA8452_DATA_CFG 0x0e
#define MMA8452_HP_FILTER_CUTOFF 0x0f
#define MMA8452_HP_FILTER_CUTOFF_SEL_MASK	(BIT(0) | BIT(1))
#define MMA8452_TRANSIENT_CFG 0x1d
#define MMA8452_TRANSIENT_CFG_ELE		BIT(4)
#define MMA8452_TRANSIENT_CFG_CHAN(chan)	BIT(chan + 1)
#define MMA8452_TRANSIENT_CFG_HPF_BYP		BIT(0)
#define MMA8452_TRANSIENT_SRC 0x1e
#define MMA8452_TRANSIENT_SRC_XTRANSE		BIT(1)
#define MMA8452_TRANSIENT_SRC_YTRANSE		BIT(3)
#define MMA8452_TRANSIENT_SRC_ZTRANSE		BIT(5)
#define MMA8452_TRANSIENT_THS 0x1f
#define MMA8452_TRANSIENT_THS_MASK	0x7f
#define MMA8452_TRANSIENT_COUNT 0x20
#define MMA8452_OFF_X 0x2f
#define MMA8452_OFF_Y 0x30
#define MMA8452_OFF_Z 0x31
#define MMA8452_CTRL_REG1 0x2a
#define MMA8452_CTRL_REG2 0x2b
#define MMA8452_CTRL_REG2_RST		BIT(6)
#define MMA8452_CTRL_REG4 0x2d
#define MMA8452_CTRL_REG5 0x2e

#define MMA8452_MAX_REG 0x31

#define MMA8452_STATUS_DRDY (BIT(2) | BIT(1) | BIT(0))

#define MMA8452_CTRL_DR_MASK (BIT(5) | BIT(4) | BIT(3))
#define MMA8452_CTRL_DR_SHIFT 3
#define MMA8452_CTRL_DR_DEFAULT 0x4 /* 50 Hz sample frequency */
#define MMA8452_CTRL_ACTIVE BIT(0)

#define MMA8452_DATA_CFG_FS_MASK (BIT(1) | BIT(0))
#define MMA8452_DATA_CFG_FS_2G 0
#define MMA8452_DATA_CFG_FS_4G 1
#define MMA8452_DATA_CFG_FS_8G 2
#define MMA8452_DATA_CFG_HPF_MASK BIT(4)

#define MMA8452_INT_DRDY	BIT(0)
#define MMA8452_INT_TRANS	BIT(5)

#define MMA8452_DEVICE_ID 0x2a

struct mma8452_data {
	struct i2c_client *client;
	struct mutex lock;
	u8 ctrl_reg1;
	u8 data_cfg;
};

static int mma8452_drdy(struct mma8452_data *data)
{
	int tries = 150;

	while (tries-- > 0) {
		int ret = i2c_smbus_read_byte_data(data->client,
			MMA8452_STATUS);
		if (ret < 0)
			return ret;
		if ((ret & MMA8452_STATUS_DRDY) == MMA8452_STATUS_DRDY)
			return 0;
		msleep(20);
	}

	dev_err(&data->client->dev, "data not ready\n");
	return -EIO;
}

static int mma8452_read(struct mma8452_data *data, __be16 buf[3])
{
	int ret = mma8452_drdy(data);
	if (ret < 0)
		return ret;
	return i2c_smbus_read_i2c_block_data(data->client,
		MMA8452_OUT_X, 3 * sizeof(__be16), (u8 *) buf);
}

static ssize_t mma8452_show_int_plus_micros(char *buf,
	const int (*vals)[2], int n)
{
	size_t len = 0;

	while (n-- > 0)
		len += scnprintf(buf + len, PAGE_SIZE - len,
			"%d.%06d ", vals[n][0], vals[n][1]);

	/* replace trailing space by newline */
	buf[len - 1] = '\n';

	return len;
}

static int mma8452_get_int_plus_micros_index(const int (*vals)[2], int n,
					int val, int val2)
{
	while (n-- > 0)
		if (val == vals[n][0] && val2 == vals[n][1])
			return n;

	return -EINVAL;
}

static int mma8452_get_odr_index(struct mma8452_data *data)
{
	return (data->ctrl_reg1 & MMA8452_CTRL_DR_MASK) >>
			MMA8452_CTRL_DR_SHIFT;
}

static const int mma8452_samp_freq[8][2] = {
	{800, 0}, {400, 0}, {200, 0}, {100, 0}, {50, 0}, {12, 500000},
	{6, 250000}, {1, 560000}
};

/*
 * Hardware has fullscale of -2G, -4G, -8G corresponding to raw value -2048
 * The userspace interface uses m/s^2 and we declare micro units
 * So scale factor is given by:
 * 	g * N * 1000000 / 2048 for N = 2, 4, 8 and g=9.80665
 */
static const int mma8452_scales[3][2] = {
	{0, 9577}, {0, 19154}, {0, 38307}
};

/* Datasheet table 35  (step time vs sample frequency) */
static const int mma8452_transient_time_step_us[8] = {
	1250,
	2500,
	5000,
	10000,
	20000,
	20000,
	20000,
	20000
};

/* Datasheet table 18 (normal mode) */
static const int mma8452_hp_filter_cutoff[8][4][2] = {
	{ {16, 0}, {8, 0}, {4, 0}, {2, 0} },		/* 800 Hz sample */
	{ {16, 0}, {8, 0}, {4, 0}, {2, 0} },		/* 400 Hz sample */
	{ {8, 0}, {4, 0}, {2, 0}, {1, 0} },		/* 200 Hz sample */
	{ {4, 0}, {2, 0}, {1, 0}, {0, 500000} },	/* 100 Hz sample */
	{ {2, 0}, {1, 0}, {0, 500000}, {0, 250000} },	/* 50 Hz sample */
	{ {2, 0}, {1, 0}, {0, 500000}, {0, 250000} },	/* 12.5 Hz sample */
	{ {2, 0}, {1, 0}, {0, 500000}, {0, 250000} },	/* 6.25 Hz sample */
	{ {2, 0}, {1, 0}, {0, 500000}, {0, 250000} }	/* 1.56 Hz sample */
};

static ssize_t mma8452_show_samp_freq_avail(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	return mma8452_show_int_plus_micros(buf, mma8452_samp_freq,
		ARRAY_SIZE(mma8452_samp_freq));
}

static ssize_t mma8452_show_scale_avail(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	return mma8452_show_int_plus_micros(buf, mma8452_scales,
		ARRAY_SIZE(mma8452_scales));
}

static ssize_t mma8452_show_hp_cutoff_avail(struct device *dev,
					    struct device_attribute *attr,
					    char *buf)
{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct mma8452_data *data = iio_priv(indio_dev);
	int i = mma8452_get_odr_index(data);

	return mma8452_show_int_plus_micros(buf, mma8452_hp_filter_cutoff[i],
		ARRAY_SIZE(mma8452_hp_filter_cutoff[0]));
}

static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mma8452_show_samp_freq_avail);
static IIO_DEVICE_ATTR(in_accel_scale_available, S_IRUGO,
	mma8452_show_scale_avail, NULL, 0);
static IIO_DEVICE_ATTR(in_accel_filter_high_pass_3db_frequency_available,
			S_IRUGO, mma8452_show_hp_cutoff_avail, NULL, 0);

static int mma8452_get_samp_freq_index(struct mma8452_data *data,
	int val, int val2)
{
	return mma8452_get_int_plus_micros_index(mma8452_samp_freq,
		ARRAY_SIZE(mma8452_samp_freq), val, val2);
}

static int mma8452_get_scale_index(struct mma8452_data *data,
	int val, int val2)
{
	return mma8452_get_int_plus_micros_index(mma8452_scales,
		ARRAY_SIZE(mma8452_scales), val, val2);
}

static int mma8452_get_hp_filter_index(struct mma8452_data *data,
				       int val, int val2)
{
	int i = mma8452_get_odr_index(data);

	return mma8452_get_int_plus_micros_index(mma8452_hp_filter_cutoff[i],
		ARRAY_SIZE(mma8452_scales[0]), val, val2);
}

static int mma8452_read_hp_filter(struct mma8452_data *data, int *hz, int *uHz)
{
	int i, ret;

	ret = i2c_smbus_read_byte_data(data->client, MMA8452_HP_FILTER_CUTOFF);
	if (ret < 0)
		return ret;

	i = mma8452_get_odr_index(data);
	ret &= MMA8452_HP_FILTER_CUTOFF_SEL_MASK;
	*hz = mma8452_hp_filter_cutoff[i][ret][0];
	*uHz = mma8452_hp_filter_cutoff[i][ret][1];

	return 0;
}

static int mma8452_read_raw(struct iio_dev *indio_dev,
			    struct iio_chan_spec const *chan,
			    int *val, int *val2, long mask)
{
	struct mma8452_data *data = iio_priv(indio_dev);
	__be16 buffer[3];
	int i, ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		if (iio_buffer_enabled(indio_dev))
			return -EBUSY;

		mutex_lock(&data->lock);
		ret = mma8452_read(data, buffer);
		mutex_unlock(&data->lock);
		if (ret < 0)
			return ret;
		*val = sign_extend32(
			be16_to_cpu(buffer[chan->scan_index]) >> 4, 11);
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
		i = data->data_cfg & MMA8452_DATA_CFG_FS_MASK;
		*val = mma8452_scales[i][0];
		*val2 = mma8452_scales[i][1];
		return IIO_VAL_INT_PLUS_MICRO;
	case IIO_CHAN_INFO_SAMP_FREQ:
		i = mma8452_get_odr_index(data);
		*val = mma8452_samp_freq[i][0];
		*val2 = mma8452_samp_freq[i][1];
		return IIO_VAL_INT_PLUS_MICRO;
	case IIO_CHAN_INFO_CALIBBIAS:
		ret = i2c_smbus_read_byte_data(data->client, MMA8452_OFF_X +
			chan->scan_index);
		if (ret < 0)
			return ret;
		*val = sign_extend32(ret, 7);
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
		if (data->data_cfg & MMA8452_DATA_CFG_HPF_MASK) {
			ret = mma8452_read_hp_filter(data, val, val2);
			if (ret < 0)
				return ret;
		} else {
			*val = 0;
			*val2 = 0;
		}
		return IIO_VAL_INT_PLUS_MICRO;
	}
	return -EINVAL;
}

static int mma8452_standby(struct mma8452_data *data)
{
	return i2c_smbus_write_byte_data(data->client, MMA8452_CTRL_REG1,
		data->ctrl_reg1 & ~MMA8452_CTRL_ACTIVE);
}

static int mma8452_active(struct mma8452_data *data)
{
	return i2c_smbus_write_byte_data(data->client, MMA8452_CTRL_REG1,
		data->ctrl_reg1);
}

static int mma8452_change_config(struct mma8452_data *data, u8 reg, u8 val)
{
	int ret;

	mutex_lock(&data->lock);

	/* config can only be changed when in standby */
	ret = mma8452_standby(data);
	if (ret < 0)
		goto fail;

	ret = i2c_smbus_write_byte_data(data->client, reg, val);
	if (ret < 0)
		goto fail;

	ret = mma8452_active(data);
	if (ret < 0)
		goto fail;

	ret = 0;
fail:
	mutex_unlock(&data->lock);
	return ret;
}

static int mma8452_set_hp_filter_frequency(struct mma8452_data *data,
					   int val, int val2)
{
	int i, reg;

	i = mma8452_get_hp_filter_index(data, val, val2);
	if (i < 0)
		return -EINVAL;

	reg = i2c_smbus_read_byte_data(data->client,
				       MMA8452_HP_FILTER_CUTOFF);
	if (reg < 0)
		return reg;
	reg &= ~MMA8452_HP_FILTER_CUTOFF_SEL_MASK;
	reg |= i;

	return mma8452_change_config(data, MMA8452_HP_FILTER_CUTOFF, reg);
}

static int mma8452_write_raw(struct iio_dev *indio_dev,
			     struct iio_chan_spec const *chan,
			     int val, int val2, long mask)
{
	struct mma8452_data *data = iio_priv(indio_dev);
	int i, ret;

	if (iio_buffer_enabled(indio_dev))
		return -EBUSY;

	switch (mask) {
	case IIO_CHAN_INFO_SAMP_FREQ:
		i = mma8452_get_samp_freq_index(data, val, val2);
		if (i < 0)
			return -EINVAL;

		data->ctrl_reg1 &= ~MMA8452_CTRL_DR_MASK;
		data->ctrl_reg1 |= i << MMA8452_CTRL_DR_SHIFT;
		return mma8452_change_config(data, MMA8452_CTRL_REG1,
			data->ctrl_reg1);
	case IIO_CHAN_INFO_SCALE:
		i = mma8452_get_scale_index(data, val, val2);
		if (i < 0)
			return -EINVAL;
		data->data_cfg &= ~MMA8452_DATA_CFG_FS_MASK;
		data->data_cfg |= i;
		return mma8452_change_config(data, MMA8452_DATA_CFG,
			data->data_cfg);
	case IIO_CHAN_INFO_CALIBBIAS:
		if (val < -128 || val > 127)
			return -EINVAL;
		return mma8452_change_config(data, MMA8452_OFF_X +
			chan->scan_index, val);

	case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
		if (val == 0 && val2 == 0) {
			data->data_cfg &= ~MMA8452_DATA_CFG_HPF_MASK;
		} else {
			data->data_cfg |= MMA8452_DATA_CFG_HPF_MASK;
			ret = mma8452_set_hp_filter_frequency(data, val, val2);
			if (ret < 0)
				return ret;
		}
		return mma8452_change_config(data, MMA8452_DATA_CFG,
						data->data_cfg);

	default:
		return -EINVAL;
	}
}

static int mma8452_read_thresh(struct iio_dev *indio_dev,
			       const struct iio_chan_spec *chan,
			       enum iio_event_type type,
			       enum iio_event_direction dir,
			       enum iio_event_info info,
			       int *val, int *val2)
{
	struct mma8452_data *data = iio_priv(indio_dev);
	int ret, us;

	switch (info) {
	case IIO_EV_INFO_VALUE:
		ret = i2c_smbus_read_byte_data(data->client,
					       MMA8452_TRANSIENT_THS);
		if (ret < 0)
			return ret;

		*val = ret & MMA8452_TRANSIENT_THS_MASK;
		return IIO_VAL_INT;

	case IIO_EV_INFO_PERIOD:
		ret = i2c_smbus_read_byte_data(data->client,
					       MMA8452_TRANSIENT_COUNT);
		if (ret < 0)
			return ret;

		us = ret * mma8452_transient_time_step_us[
				mma8452_get_odr_index(data)];
		*val = us / USEC_PER_SEC;
		*val2 = us % USEC_PER_SEC;
		return IIO_VAL_INT_PLUS_MICRO;

	case IIO_EV_INFO_HIGH_PASS_FILTER_3DB:
		ret = i2c_smbus_read_byte_data(data->client,
					       MMA8452_TRANSIENT_CFG);
		if (ret < 0)
			return ret;

		if (ret & MMA8452_TRANSIENT_CFG_HPF_BYP) {
			*val = 0;
			*val2 = 0;
		} else {
			ret = mma8452_read_hp_filter(data, val, val2);
			if (ret < 0)
				return ret;
		}
		return IIO_VAL_INT_PLUS_MICRO;

	default:
		return -EINVAL;
	}
}

static int mma8452_write_thresh(struct iio_dev *indio_dev,
				const struct iio_chan_spec *chan,
				enum iio_event_type type,
				enum iio_event_direction dir,
				enum iio_event_info info,
				int val, int val2)
{
	struct mma8452_data *data = iio_priv(indio_dev);
	int ret, reg, steps;

	switch (info) {
	case IIO_EV_INFO_VALUE:
		return mma8452_change_config(data, MMA8452_TRANSIENT_THS,
					     val & MMA8452_TRANSIENT_THS_MASK);

	case IIO_EV_INFO_PERIOD:
		steps = (val * USEC_PER_SEC + val2) /
				mma8452_transient_time_step_us[
					mma8452_get_odr_index(data)];

		if (steps > 0xff)
			return -EINVAL;

		return mma8452_change_config(data, MMA8452_TRANSIENT_COUNT,
					     steps);
	case IIO_EV_INFO_HIGH_PASS_FILTER_3DB:
		reg = i2c_smbus_read_byte_data(data->client,
					       MMA8452_TRANSIENT_CFG);
		if (reg < 0)
			return reg;

		if (val == 0 && val2 == 0) {
			reg |= MMA8452_TRANSIENT_CFG_HPF_BYP;
		} else {
			reg &= ~MMA8452_TRANSIENT_CFG_HPF_BYP;
			ret = mma8452_set_hp_filter_frequency(data, val, val2);
			if (ret < 0)
				return ret;
		}
		return mma8452_change_config(data, MMA8452_TRANSIENT_CFG, reg);

	default:
		return -EINVAL;
	}
}

static int mma8452_read_event_config(struct iio_dev *indio_dev,
				     const struct iio_chan_spec *chan,
				     enum iio_event_type type,
				     enum iio_event_direction dir)
{
	struct mma8452_data *data = iio_priv(indio_dev);
	int ret;

	ret = i2c_smbus_read_byte_data(data->client, MMA8452_TRANSIENT_CFG);
	if (ret < 0)
		return ret;

	return ret & MMA8452_TRANSIENT_CFG_CHAN(chan->scan_index) ? 1 : 0;
}

static int mma8452_write_event_config(struct iio_dev *indio_dev,
				      const struct iio_chan_spec *chan,
				      enum iio_event_type type,
				      enum iio_event_direction dir,
				      int state)
{
	struct mma8452_data *data = iio_priv(indio_dev);
	int val;

	val = i2c_smbus_read_byte_data(data->client, MMA8452_TRANSIENT_CFG);
	if (val < 0)
		return val;

	if (state)
		val |= MMA8452_TRANSIENT_CFG_CHAN(chan->scan_index);
	else
		val &= ~MMA8452_TRANSIENT_CFG_CHAN(chan->scan_index);

	val |= MMA8452_TRANSIENT_CFG_ELE;

	return mma8452_change_config(data, MMA8452_TRANSIENT_CFG, val);
}

static void mma8452_transient_interrupt(struct iio_dev *indio_dev)
{
	struct mma8452_data *data = iio_priv(indio_dev);
	s64 ts = iio_get_time_ns();
	int src;

	src = i2c_smbus_read_byte_data(data->client, MMA8452_TRANSIENT_SRC);
	if (src < 0)
		return;

	if (src & MMA8452_TRANSIENT_SRC_XTRANSE)
		iio_push_event(indio_dev,
			       IIO_MOD_EVENT_CODE(IIO_ACCEL, 0, IIO_MOD_X,
						  IIO_EV_TYPE_MAG,
						  IIO_EV_DIR_RISING),
			       ts);

	if (src & MMA8452_TRANSIENT_SRC_YTRANSE)
		iio_push_event(indio_dev,
			       IIO_MOD_EVENT_CODE(IIO_ACCEL, 0, IIO_MOD_Y,
						  IIO_EV_TYPE_MAG,
						  IIO_EV_DIR_RISING),
			       ts);

	if (src & MMA8452_TRANSIENT_SRC_ZTRANSE)
		iio_push_event(indio_dev,
			       IIO_MOD_EVENT_CODE(IIO_ACCEL, 0, IIO_MOD_Z,
						  IIO_EV_TYPE_MAG,
						  IIO_EV_DIR_RISING),
			       ts);
}

static irqreturn_t mma8452_interrupt(int irq, void *p)
{
	struct iio_dev *indio_dev = p;
	struct mma8452_data *data = iio_priv(indio_dev);
	int ret = IRQ_NONE;
	int src;

	src = i2c_smbus_read_byte_data(data->client, MMA8452_INT_SRC);
	if (src < 0)
		return IRQ_NONE;

	if (src & MMA8452_INT_DRDY) {
		iio_trigger_poll_chained(indio_dev->trig);
		ret = IRQ_HANDLED;
	}

	if (src & MMA8452_INT_TRANS) {
		mma8452_transient_interrupt(indio_dev);
		ret = IRQ_HANDLED;
	}

	return ret;
}

static irqreturn_t mma8452_trigger_handler(int irq, void *p)
{
	struct iio_poll_func *pf = p;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct mma8452_data *data = iio_priv(indio_dev);
	u8 buffer[16]; /* 3 16-bit channels + padding + ts */
	int ret;

	ret = mma8452_read(data, (__be16 *) buffer);
	if (ret < 0)
		goto done;

	iio_push_to_buffers_with_timestamp(indio_dev, buffer,
		iio_get_time_ns());

done:
	iio_trigger_notify_done(indio_dev->trig);
	return IRQ_HANDLED;
}

static int mma8452_reg_access_dbg(struct iio_dev *indio_dev,
				  unsigned reg, unsigned writeval,
				  unsigned *readval)
{
	int ret;
	struct mma8452_data *data = iio_priv(indio_dev);

	if (reg > MMA8452_MAX_REG)
		return -EINVAL;

	if (!readval)
		return mma8452_change_config(data, reg, writeval);

	ret = i2c_smbus_read_byte_data(data->client, reg);
	if (ret < 0)
		return ret;

	*readval = ret;

	return 0;
}

static const struct iio_event_spec mma8452_transient_event[] = {
	{
		.type = IIO_EV_TYPE_MAG,
		.dir = IIO_EV_DIR_RISING,
		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
		.mask_shared_by_type = BIT(IIO_EV_INFO_VALUE) |
					BIT(IIO_EV_INFO_PERIOD) |
					BIT(IIO_EV_INFO_HIGH_PASS_FILTER_3DB)
	},
};

/*
 * Threshold is configured in fixed 8G/127 steps regardless of
 * currently selected scale for measurement.
 */
static IIO_CONST_ATTR_NAMED(accel_transient_scale, in_accel_scale, "0.617742");

static struct attribute *mma8452_event_attributes[] = {
	&iio_const_attr_accel_transient_scale.dev_attr.attr,
	NULL,
};

static struct attribute_group mma8452_event_attribute_group = {
	.attrs = mma8452_event_attributes,
	.name = "events",
};

#define MMA8452_CHANNEL(axis, idx) { \
	.type = IIO_ACCEL, \
	.modified = 1, \
	.channel2 = IIO_MOD_##axis, \
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
		BIT(IIO_CHAN_INFO_CALIBBIAS), \
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
		BIT(IIO_CHAN_INFO_SCALE) | \
		BIT(IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY), \
	.scan_index = idx, \
	.scan_type = { \
		.sign = 's', \
		.realbits = 12, \
		.storagebits = 16, \
		.shift = 4, \
		.endianness = IIO_BE, \
	}, \
	.event_spec = mma8452_transient_event, \
	.num_event_specs = ARRAY_SIZE(mma8452_transient_event), \
}

static const struct iio_chan_spec mma8452_channels[] = {
	MMA8452_CHANNEL(X, 0),
	MMA8452_CHANNEL(Y, 1),
	MMA8452_CHANNEL(Z, 2),
	IIO_CHAN_SOFT_TIMESTAMP(3),
};

static struct attribute *mma8452_attributes[] = {
	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
	&iio_dev_attr_in_accel_scale_available.dev_attr.attr,
	&iio_dev_attr_in_accel_filter_high_pass_3db_frequency_available.dev_attr.attr,
	NULL
};

static const struct attribute_group mma8452_group = {
	.attrs = mma8452_attributes,
};

static const struct iio_info mma8452_info = {
	.attrs = &mma8452_group,
	.read_raw = &mma8452_read_raw,
	.write_raw = &mma8452_write_raw,
	.event_attrs = &mma8452_event_attribute_group,
	.read_event_value = &mma8452_read_thresh,
	.write_event_value = &mma8452_write_thresh,
	.read_event_config = &mma8452_read_event_config,
	.write_event_config = &mma8452_write_event_config,
	.debugfs_reg_access = &mma8452_reg_access_dbg,
	.driver_module = THIS_MODULE,
};

static const unsigned long mma8452_scan_masks[] = {0x7, 0};

static int mma8452_data_rdy_trigger_set_state(struct iio_trigger *trig,
					      bool state)
{
	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
	struct mma8452_data *data = iio_priv(indio_dev);
	int reg;

	reg = i2c_smbus_read_byte_data(data->client, MMA8452_CTRL_REG4);
	if (reg < 0)
		return reg;

	if (state)
		reg |= MMA8452_INT_DRDY;
	else
		reg &= ~MMA8452_INT_DRDY;

	return mma8452_change_config(data, MMA8452_CTRL_REG4, reg);
}

static int mma8452_validate_device(struct iio_trigger *trig,
				   struct iio_dev *indio_dev)
{
	struct iio_dev *indio = iio_trigger_get_drvdata(trig);

	if (indio != indio_dev)
		return -EINVAL;

	return 0;
}

static const struct iio_trigger_ops mma8452_trigger_ops = {
	.set_trigger_state = mma8452_data_rdy_trigger_set_state,
	.validate_device = mma8452_validate_device,
	.owner = THIS_MODULE,
};

static int mma8452_trigger_setup(struct iio_dev *indio_dev)
{
	struct mma8452_data *data = iio_priv(indio_dev);
	struct iio_trigger *trig;
	int ret;

	trig = devm_iio_trigger_alloc(&data->client->dev, "%s-dev%d",
				      indio_dev->name,
				      indio_dev->id);
	if (!trig)
		return -ENOMEM;

	trig->dev.parent = &data->client->dev;
	trig->ops = &mma8452_trigger_ops;
	iio_trigger_set_drvdata(trig, indio_dev);

	ret = iio_trigger_register(trig);
	if (ret)
		return ret;

	indio_dev->trig = trig;
	return 0;
}

static void mma8452_trigger_cleanup(struct iio_dev *indio_dev)
{
	if (indio_dev->trig)
		iio_trigger_unregister(indio_dev->trig);
}

static int mma8452_reset(struct i2c_client *client)
{
	int i;
	int ret;

	ret = i2c_smbus_write_byte_data(client,	MMA8452_CTRL_REG2,
					MMA8452_CTRL_REG2_RST);
	if (ret < 0)
		return ret;

	for (i = 0; i < 10; i++) {
		usleep_range(100, 200);
		ret = i2c_smbus_read_byte_data(client, MMA8452_CTRL_REG2);
		if (ret == -EIO)
			continue; /* I2C comm reset */
		if (ret < 0)
			return ret;
		if (!(ret & MMA8452_CTRL_REG2_RST))
			return 0;
	}

	return -ETIMEDOUT;
}

static int mma8452_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct mma8452_data *data;
	struct iio_dev *indio_dev;
	int ret;

	ret = i2c_smbus_read_byte_data(client, MMA8452_WHO_AM_I);
	if (ret < 0)
		return ret;
	if (ret != MMA8452_DEVICE_ID)
		return -ENODEV;

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

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

	i2c_set_clientdata(client, indio_dev);
	indio_dev->info = &mma8452_info;
	indio_dev->name = id->name;
	indio_dev->dev.parent = &client->dev;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels = mma8452_channels;
	indio_dev->num_channels = ARRAY_SIZE(mma8452_channels);
	indio_dev->available_scan_masks = mma8452_scan_masks;

	ret = mma8452_reset(client);
	if (ret < 0)
		return ret;

	data->data_cfg = MMA8452_DATA_CFG_FS_2G;
	ret = i2c_smbus_write_byte_data(client, MMA8452_DATA_CFG,
		data->data_cfg);
	if (ret < 0)
		return ret;

	/*
	 * By default set transient threshold to max to avoid events if
	 * enabling without configuring threshold.
	 */
	ret = i2c_smbus_write_byte_data(client, MMA8452_TRANSIENT_THS,
					MMA8452_TRANSIENT_THS_MASK);
	if (ret < 0)
		return ret;

	if (client->irq) {
		/*
		 * Although we enable the transient interrupt source once and
		 * for all here the transient event detection itself is not
		 * enabled until userspace asks for it by
		 * mma8452_write_event_config()
		 */
		int supported_interrupts = MMA8452_INT_DRDY | MMA8452_INT_TRANS;
		int enabled_interrupts = MMA8452_INT_TRANS;

		/* Assume wired to INT1 pin */
		ret = i2c_smbus_write_byte_data(client,
						MMA8452_CTRL_REG5,
						supported_interrupts);
		if (ret < 0)
			return ret;

		ret = i2c_smbus_write_byte_data(client,
						MMA8452_CTRL_REG4,
						enabled_interrupts);
		if (ret < 0)
			return ret;

		ret = mma8452_trigger_setup(indio_dev);
		if (ret < 0)
			return ret;
	}

	data->ctrl_reg1 = MMA8452_CTRL_ACTIVE |
		(MMA8452_CTRL_DR_DEFAULT << MMA8452_CTRL_DR_SHIFT);
	ret = i2c_smbus_write_byte_data(client, MMA8452_CTRL_REG1,
					data->ctrl_reg1);
	if (ret < 0)
		goto trigger_cleanup;

	ret = iio_triggered_buffer_setup(indio_dev, NULL,
		mma8452_trigger_handler, NULL);
	if (ret < 0)
		goto trigger_cleanup;

	if (client->irq) {
		ret = devm_request_threaded_irq(&client->dev,
						client->irq,
						NULL, mma8452_interrupt,
						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
						client->name, indio_dev);
		if (ret)
			goto buffer_cleanup;
	}

	ret = iio_device_register(indio_dev);
	if (ret < 0)
		goto buffer_cleanup;

	return 0;

buffer_cleanup:
	iio_triggered_buffer_cleanup(indio_dev);

trigger_cleanup:
	mma8452_trigger_cleanup(indio_dev);

	return ret;
}

static int mma8452_remove(struct i2c_client *client)
{
	struct iio_dev *indio_dev = i2c_get_clientdata(client);

	iio_device_unregister(indio_dev);
	iio_triggered_buffer_cleanup(indio_dev);
	mma8452_trigger_cleanup(indio_dev);
	mma8452_standby(iio_priv(indio_dev));

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int mma8452_suspend(struct device *dev)
{
	return mma8452_standby(iio_priv(i2c_get_clientdata(
		to_i2c_client(dev))));
}

static int mma8452_resume(struct device *dev)
{
	return mma8452_active(iio_priv(i2c_get_clientdata(
		to_i2c_client(dev))));
}

static SIMPLE_DEV_PM_OPS(mma8452_pm_ops, mma8452_suspend, mma8452_resume);
#define MMA8452_PM_OPS (&mma8452_pm_ops)
#else
#define MMA8452_PM_OPS NULL
#endif

static const struct i2c_device_id mma8452_id[] = {
	{ "mma8452", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, mma8452_id);

static const struct of_device_id mma8452_dt_ids[] = {
	{ .compatible = "fsl,mma8452" },
	{ }
};

static struct i2c_driver mma8452_driver = {
	.driver = {
		.name	= "mma8452",
		.of_match_table = of_match_ptr(mma8452_dt_ids),
		.pm	= MMA8452_PM_OPS,
	},
	.probe = mma8452_probe,
	.remove = mma8452_remove,
	.id_table = mma8452_id,
};
module_i2c_driver(mma8452_driver);

MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
MODULE_DESCRIPTION("Freescale MMA8452 accelerometer driver");
MODULE_LICENSE("GPL");