Free Electrons

Embedded Linux Experts

   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
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
/*
 * sca3000_core.c -- support VTI sca3000 series accelerometers via SPI
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * Copyright (c) 2009 Jonathan Cameron <jic23@kernel.org>
 *
 * See industrialio/accels/sca3000.h for comments.
 */

#include <linux/interrupt.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/spi/spi.h>
#include <linux/sysfs.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/events.h>
#include <linux/iio/buffer.h>

#include "sca3000.h"

enum sca3000_variant {
	d01,
	e02,
	e04,
	e05,
};

/*
 * Note where option modes are not defined, the chip simply does not
 * support any.
 * Other chips in the sca3000 series use i2c and are not included here.
 *
 * Some of these devices are only listed in the family data sheet and
 * do not actually appear to be available.
 */
static const struct sca3000_chip_info sca3000_spi_chip_info_tbl[] = {
	[d01] = {
		.scale = 7357,
		.temp_output = true,
		.measurement_mode_freq = 250,
		.option_mode_1 = SCA3000_OP_MODE_BYPASS,
		.option_mode_1_freq = 250,
		.mot_det_mult_xz = {50, 100, 200, 350, 650, 1300},
		.mot_det_mult_y = {50, 100, 150, 250, 450, 850, 1750},
	},
	[e02] = {
		.scale = 9810,
		.measurement_mode_freq = 125,
		.option_mode_1 = SCA3000_OP_MODE_NARROW,
		.option_mode_1_freq = 63,
		.mot_det_mult_xz = {100, 150, 300, 550, 1050, 2050},
		.mot_det_mult_y = {50, 100, 200, 350, 700, 1350, 2700},
	},
	[e04] = {
		.scale = 19620,
		.measurement_mode_freq = 100,
		.option_mode_1 = SCA3000_OP_MODE_NARROW,
		.option_mode_1_freq = 50,
		.option_mode_2 = SCA3000_OP_MODE_WIDE,
		.option_mode_2_freq = 400,
		.mot_det_mult_xz = {200, 300, 600, 1100, 2100, 4100},
		.mot_det_mult_y = {100, 200, 400, 7000, 1400, 2700, 54000},
	},
	[e05] = {
		.scale = 61313,
		.measurement_mode_freq = 200,
		.option_mode_1 = SCA3000_OP_MODE_NARROW,
		.option_mode_1_freq = 50,
		.option_mode_2 = SCA3000_OP_MODE_WIDE,
		.option_mode_2_freq = 400,
		.mot_det_mult_xz = {600, 900, 1700, 3200, 6100, 11900},
		.mot_det_mult_y = {300, 600, 1200, 2000, 4100, 7800, 15600},
	},
};

int sca3000_write_reg(struct sca3000_state *st, u8 address, u8 val)
{
	st->tx[0] = SCA3000_WRITE_REG(address);
	st->tx[1] = val;
	return spi_write(st->us, st->tx, 2);
}

int sca3000_read_data_short(struct sca3000_state *st,
			    u8 reg_address_high,
			    int len)
{
	struct spi_transfer xfer[2] = {
		{
			.len = 1,
			.tx_buf = st->tx,
		}, {
			.len = len,
			.rx_buf = st->rx,
		}
	};
	st->tx[0] = SCA3000_READ_REG(reg_address_high);

	return spi_sync_transfer(st->us, xfer, ARRAY_SIZE(xfer));
}

/**
 * sca3000_reg_lock_on() test if the ctrl register lock is on
 *
 * Lock must be held.
 **/
static int sca3000_reg_lock_on(struct sca3000_state *st)
{
	int ret;

	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_STATUS, 1);
	if (ret < 0)
		return ret;

	return !(st->rx[0] & SCA3000_LOCKED);
}

/**
 * __sca3000_unlock_reg_lock() unlock the control registers
 *
 * Note the device does not appear to support doing this in a single transfer.
 * This should only ever be used as part of ctrl reg read.
 * Lock must be held before calling this
 **/
static int __sca3000_unlock_reg_lock(struct sca3000_state *st)
{
	struct spi_transfer xfer[3] = {
		{
			.len = 2,
			.cs_change = 1,
			.tx_buf = st->tx,
		}, {
			.len = 2,
			.cs_change = 1,
			.tx_buf = st->tx + 2,
		}, {
			.len = 2,
			.tx_buf = st->tx + 4,
		},
	};
	st->tx[0] = SCA3000_WRITE_REG(SCA3000_REG_ADDR_UNLOCK);
	st->tx[1] = 0x00;
	st->tx[2] = SCA3000_WRITE_REG(SCA3000_REG_ADDR_UNLOCK);
	st->tx[3] = 0x50;
	st->tx[4] = SCA3000_WRITE_REG(SCA3000_REG_ADDR_UNLOCK);
	st->tx[5] = 0xA0;

	return spi_sync_transfer(st->us, xfer, ARRAY_SIZE(xfer));
}

/**
 * sca3000_write_ctrl_reg() write to a lock protect ctrl register
 * @sel: selects which registers we wish to write to
 * @val: the value to be written
 *
 * Certain control registers are protected against overwriting by the lock
 * register and use a shared write address. This function allows writing of
 * these registers.
 * Lock must be held.
 **/
static int sca3000_write_ctrl_reg(struct sca3000_state *st,
				  u8 sel,
				  uint8_t val)
{
	int ret;

	ret = sca3000_reg_lock_on(st);
	if (ret < 0)
		goto error_ret;
	if (ret) {
		ret = __sca3000_unlock_reg_lock(st);
		if (ret)
			goto error_ret;
	}

	/* Set the control select register */
	ret = sca3000_write_reg(st, SCA3000_REG_ADDR_CTRL_SEL, sel);
	if (ret)
		goto error_ret;

	/* Write the actual value into the register */
	ret = sca3000_write_reg(st, SCA3000_REG_ADDR_CTRL_DATA, val);

error_ret:
	return ret;
}

/**
 * sca3000_read_ctrl_reg() read from lock protected control register.
 *
 * Lock must be held.
 **/
static int sca3000_read_ctrl_reg(struct sca3000_state *st,
				 u8 ctrl_reg)
{
	int ret;

	ret = sca3000_reg_lock_on(st);
	if (ret < 0)
		goto error_ret;
	if (ret) {
		ret = __sca3000_unlock_reg_lock(st);
		if (ret)
			goto error_ret;
	}
	/* Set the control select register */
	ret = sca3000_write_reg(st, SCA3000_REG_ADDR_CTRL_SEL, ctrl_reg);
	if (ret)
		goto error_ret;
	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_CTRL_DATA, 1);
	if (ret)
		goto error_ret;
	else
		return st->rx[0];
error_ret:
	return ret;
}

/**
 * sca3000_show_rev() - sysfs interface to read the chip revision number
 **/
static ssize_t sca3000_show_rev(struct device *dev,
				struct device_attribute *attr,
				char *buf)
{
	int len = 0, ret;
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct sca3000_state *st = iio_priv(indio_dev);

	mutex_lock(&st->lock);
	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_REVID, 1);
	if (ret < 0)
		goto error_ret;
	len += sprintf(buf + len,
		       "major=%d, minor=%d\n",
		       st->rx[0] & SCA3000_REVID_MAJOR_MASK,
		       st->rx[0] & SCA3000_REVID_MINOR_MASK);
error_ret:
	mutex_unlock(&st->lock);

	return ret ? ret : len;
}

/**
 * sca3000_show_available_measurement_modes() display available modes
 *
 * This is all read from chip specific data in the driver. Not all
 * of the sca3000 series support modes other than normal.
 **/
static ssize_t
sca3000_show_available_measurement_modes(struct device *dev,
					 struct device_attribute *attr,
					 char *buf)
{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct sca3000_state *st = iio_priv(indio_dev);
	int len = 0;

	len += sprintf(buf + len, "0 - normal mode");
	switch (st->info->option_mode_1) {
	case SCA3000_OP_MODE_NARROW:
		len += sprintf(buf + len, ", 1 - narrow mode");
		break;
	case SCA3000_OP_MODE_BYPASS:
		len += sprintf(buf + len, ", 1 - bypass mode");
		break;
	}
	switch (st->info->option_mode_2) {
	case SCA3000_OP_MODE_WIDE:
		len += sprintf(buf + len, ", 2 - wide mode");
		break;
	}
	/* always supported */
	len += sprintf(buf + len, " 3 - motion detection\n");

	return len;
}

/**
 * sca3000_show_measurement_mode() sysfs read of current mode
 **/
static ssize_t
sca3000_show_measurement_mode(struct device *dev,
			      struct device_attribute *attr,
			      char *buf)
{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct sca3000_state *st = iio_priv(indio_dev);
	int len = 0, ret;

	mutex_lock(&st->lock);
	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
	if (ret)
		goto error_ret;
	/* mask bottom 2 bits - only ones that are relevant */
	st->rx[0] &= 0x03;
	switch (st->rx[0]) {
	case SCA3000_MEAS_MODE_NORMAL:
		len += sprintf(buf + len, "0 - normal mode\n");
		break;
	case SCA3000_MEAS_MODE_MOT_DET:
		len += sprintf(buf + len, "3 - motion detection\n");
		break;
	case SCA3000_MEAS_MODE_OP_1:
		switch (st->info->option_mode_1) {
		case SCA3000_OP_MODE_NARROW:
			len += sprintf(buf + len, "1 - narrow mode\n");
			break;
		case SCA3000_OP_MODE_BYPASS:
			len += sprintf(buf + len, "1 - bypass mode\n");
			break;
		}
		break;
	case SCA3000_MEAS_MODE_OP_2:
		switch (st->info->option_mode_2) {
		case SCA3000_OP_MODE_WIDE:
			len += sprintf(buf + len, "2 - wide mode\n");
			break;
		}
		break;
	}

error_ret:
	mutex_unlock(&st->lock);

	return ret ? ret : len;
}

/**
 * sca3000_store_measurement_mode() set the current mode
 **/
static ssize_t
sca3000_store_measurement_mode(struct device *dev,
			       struct device_attribute *attr,
			       const char *buf,
			       size_t len)
{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct sca3000_state *st = iio_priv(indio_dev);
	int ret;
	u8 mask = 0x03;
	u8 val;

	mutex_lock(&st->lock);
	ret = kstrtou8(buf, 10, &val);
	if (ret)
		goto error_ret;
	if (val > 3) {
		ret = -EINVAL;
		goto error_ret;
	}
	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
	if (ret)
		goto error_ret;
	st->rx[0] &= ~mask;
	st->rx[0] |= (val & mask);
	ret = sca3000_write_reg(st, SCA3000_REG_ADDR_MODE, st->rx[0]);
	if (ret)
		goto error_ret;
	mutex_unlock(&st->lock);

	return len;

error_ret:
	mutex_unlock(&st->lock);

	return ret;
}

/*
 * Not even vaguely standard attributes so defined here rather than
 * in the relevant IIO core headers
 */
static IIO_DEVICE_ATTR(measurement_mode_available, S_IRUGO,
		       sca3000_show_available_measurement_modes,
		       NULL, 0);

static IIO_DEVICE_ATTR(measurement_mode, S_IRUGO | S_IWUSR,
		       sca3000_show_measurement_mode,
		       sca3000_store_measurement_mode,
		       0);

/* More standard attributes */

static IIO_DEVICE_ATTR(revision, S_IRUGO, sca3000_show_rev, NULL, 0);

static const struct iio_event_spec sca3000_event = {
	.type = IIO_EV_TYPE_MAG,
	.dir = IIO_EV_DIR_RISING,
	.mask_separate = BIT(IIO_EV_INFO_VALUE) | BIT(IIO_EV_INFO_ENABLE),
};

#define SCA3000_CHAN(index, mod)				\
	{							\
		.type = IIO_ACCEL,				\
		.modified = 1,					\
		.channel2 = mod,				\
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\
		.address = index,				\
		.scan_index = index,				\
		.scan_type = {					\
			.sign = 's',				\
			.realbits = 11,				\
			.storagebits = 16,			\
			.shift = 5,				\
		},						\
		.event_spec = &sca3000_event,			\
		.num_event_specs = 1,				\
	 }

static const struct iio_chan_spec sca3000_channels[] = {
	SCA3000_CHAN(0, IIO_MOD_X),
	SCA3000_CHAN(1, IIO_MOD_Y),
	SCA3000_CHAN(2, IIO_MOD_Z),
};

static const struct iio_chan_spec sca3000_channels_with_temp[] = {
	SCA3000_CHAN(0, IIO_MOD_X),
	SCA3000_CHAN(1, IIO_MOD_Y),
	SCA3000_CHAN(2, IIO_MOD_Z),
	{
		.type = IIO_TEMP,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |
			BIT(IIO_CHAN_INFO_OFFSET),
		/* No buffer support */
		.scan_index = -1,
	},
};

static u8 sca3000_addresses[3][3] = {
	[0] = {SCA3000_REG_ADDR_X_MSB, SCA3000_REG_CTRL_SEL_MD_X_TH,
	       SCA3000_MD_CTRL_OR_X},
	[1] = {SCA3000_REG_ADDR_Y_MSB, SCA3000_REG_CTRL_SEL_MD_Y_TH,
	       SCA3000_MD_CTRL_OR_Y},
	[2] = {SCA3000_REG_ADDR_Z_MSB, SCA3000_REG_CTRL_SEL_MD_Z_TH,
	       SCA3000_MD_CTRL_OR_Z},
};

static int sca3000_read_raw(struct iio_dev *indio_dev,
			    struct iio_chan_spec const *chan,
			    int *val,
			    int *val2,
			    long mask)
{
	struct sca3000_state *st = iio_priv(indio_dev);
	int ret;
	u8 address;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		mutex_lock(&st->lock);
		if (chan->type == IIO_ACCEL) {
			if (st->mo_det_use_count) {
				mutex_unlock(&st->lock);
				return -EBUSY;
			}
			address = sca3000_addresses[chan->address][0];
			ret = sca3000_read_data_short(st, address, 2);
			if (ret < 0) {
				mutex_unlock(&st->lock);
				return ret;
			}
			*val = (be16_to_cpup((__be16 *)st->rx) >> 3) & 0x1FFF;
			*val = ((*val) << (sizeof(*val) * 8 - 13)) >>
				(sizeof(*val) * 8 - 13);
		} else {
			/* get the temperature when available */
			ret = sca3000_read_data_short(st,
						      SCA3000_REG_ADDR_TEMP_MSB,
						      2);
			if (ret < 0) {
				mutex_unlock(&st->lock);
				return ret;
			}
			*val = ((st->rx[0] & 0x3F) << 3) |
			       ((st->rx[1] & 0xE0) >> 5);
		}
		mutex_unlock(&st->lock);
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
		*val = 0;
		if (chan->type == IIO_ACCEL)
			*val2 = st->info->scale;
		else /* temperature */
			*val2 = 555556;
		return IIO_VAL_INT_PLUS_MICRO;
	case IIO_CHAN_INFO_OFFSET:
		*val = -214;
		*val2 = 600000;
		return IIO_VAL_INT_PLUS_MICRO;
	default:
		return -EINVAL;
	}
}

/**
 * sca3000_read_av_freq() sysfs function to get available frequencies
 *
 * The later modes are only relevant to the ring buffer - and depend on current
 * mode. Note that data sheet gives rather wide tolerances for these so integer
 * division will give good enough answer and not all chips have them specified
 * at all.
 **/
static ssize_t sca3000_read_av_freq(struct device *dev,
				    struct device_attribute *attr,
				    char *buf)
{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct sca3000_state *st = iio_priv(indio_dev);
	int len = 0, ret, val;

	mutex_lock(&st->lock);
	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
	val = st->rx[0];
	mutex_unlock(&st->lock);
	if (ret)
		goto error_ret;

	switch (val & 0x03) {
	case SCA3000_MEAS_MODE_NORMAL:
		len += sprintf(buf + len, "%d %d %d\n",
			       st->info->measurement_mode_freq,
			       st->info->measurement_mode_freq / 2,
			       st->info->measurement_mode_freq / 4);
		break;
	case SCA3000_MEAS_MODE_OP_1:
		len += sprintf(buf + len, "%d %d %d\n",
			       st->info->option_mode_1_freq,
			       st->info->option_mode_1_freq / 2,
			       st->info->option_mode_1_freq / 4);
		break;
	case SCA3000_MEAS_MODE_OP_2:
		len += sprintf(buf + len, "%d %d %d\n",
			       st->info->option_mode_2_freq,
			       st->info->option_mode_2_freq / 2,
			       st->info->option_mode_2_freq / 4);
		break;
	}
	return len;
error_ret:
	return ret;
}

/**
 * __sca3000_get_base_freq() obtain mode specific base frequency
 *
 * lock must be held
 **/
static inline int __sca3000_get_base_freq(struct sca3000_state *st,
					  const struct sca3000_chip_info *info,
					  int *base_freq)
{
	int ret;

	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
	if (ret)
		goto error_ret;
	switch (0x03 & st->rx[0]) {
	case SCA3000_MEAS_MODE_NORMAL:
		*base_freq = info->measurement_mode_freq;
		break;
	case SCA3000_MEAS_MODE_OP_1:
		*base_freq = info->option_mode_1_freq;
		break;
	case SCA3000_MEAS_MODE_OP_2:
		*base_freq = info->option_mode_2_freq;
		break;
	}
error_ret:
	return ret;
}

/**
 * sca3000_read_frequency() sysfs interface to get the current frequency
 **/
static ssize_t sca3000_read_frequency(struct device *dev,
				      struct device_attribute *attr,
				      char *buf)
{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct sca3000_state *st = iio_priv(indio_dev);
	int ret, len = 0, base_freq = 0, val;

	mutex_lock(&st->lock);
	ret = __sca3000_get_base_freq(st, st->info, &base_freq);
	if (ret)
		goto error_ret_mut;
	ret = sca3000_read_ctrl_reg(st, SCA3000_REG_CTRL_SEL_OUT_CTRL);
	mutex_unlock(&st->lock);
	if (ret)
		goto error_ret;
	val = ret;
	if (base_freq > 0)
		switch (val & 0x03) {
		case 0x00:
		case 0x03:
			len = sprintf(buf, "%d\n", base_freq);
			break;
		case 0x01:
			len = sprintf(buf, "%d\n", base_freq / 2);
			break;
		case 0x02:
			len = sprintf(buf, "%d\n", base_freq / 4);
			break;
	}

	return len;
error_ret_mut:
	mutex_unlock(&st->lock);
error_ret:
	return ret;
}

/**
 * sca3000_set_frequency() sysfs interface to set the current frequency
 **/
static ssize_t sca3000_set_frequency(struct device *dev,
				     struct device_attribute *attr,
				     const char *buf,
				     size_t len)
{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct sca3000_state *st = iio_priv(indio_dev);
	int ret, base_freq = 0;
	int ctrlval;
	int val;

	ret = kstrtoint(buf, 10, &val);
	if (ret)
		return ret;

	mutex_lock(&st->lock);
	/* What mode are we in? */
	ret = __sca3000_get_base_freq(st, st->info, &base_freq);
	if (ret)
		goto error_free_lock;

	ret = sca3000_read_ctrl_reg(st, SCA3000_REG_CTRL_SEL_OUT_CTRL);
	if (ret < 0)
		goto error_free_lock;
	ctrlval = ret;
	/* clear the bits */
	ctrlval &= ~0x03;

	if (val == base_freq / 2) {
		ctrlval |= SCA3000_OUT_CTRL_BUF_DIV_2;
	} else if (val == base_freq / 4) {
		ctrlval |= SCA3000_OUT_CTRL_BUF_DIV_4;
	} else if (val != base_freq) {
		ret = -EINVAL;
		goto error_free_lock;
	}
	ret = sca3000_write_ctrl_reg(st, SCA3000_REG_CTRL_SEL_OUT_CTRL,
				     ctrlval);
error_free_lock:
	mutex_unlock(&st->lock);

	return ret ? ret : len;
}

/*
 * Should only really be registered if ring buffer support is compiled in.
 * Does no harm however and doing it right would add a fair bit of complexity
 */
static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(sca3000_read_av_freq);

static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
			      sca3000_read_frequency,
			      sca3000_set_frequency);

/**
 * sca3000_read_thresh() - query of a threshold
 **/
static int sca3000_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)
{
	int ret, i;
	struct sca3000_state *st = iio_priv(indio_dev);
	int num = chan->channel2;

	mutex_lock(&st->lock);
	ret = sca3000_read_ctrl_reg(st, sca3000_addresses[num][1]);
	mutex_unlock(&st->lock);
	if (ret < 0)
		return ret;
	*val = 0;
	if (num == 1)
		for_each_set_bit(i, (unsigned long *)&ret,
				 ARRAY_SIZE(st->info->mot_det_mult_y))
			*val += st->info->mot_det_mult_y[i];
	else
		for_each_set_bit(i, (unsigned long *)&ret,
				 ARRAY_SIZE(st->info->mot_det_mult_xz))
			*val += st->info->mot_det_mult_xz[i];

	return IIO_VAL_INT;
}

/**
 * sca3000_write_thresh() control of threshold
 **/
static int sca3000_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 sca3000_state *st = iio_priv(indio_dev);
	int num = chan->channel2;
	int ret;
	int i;
	u8 nonlinear = 0;

	if (num == 1) {
		i = ARRAY_SIZE(st->info->mot_det_mult_y);
		while (i > 0)
			if (val >= st->info->mot_det_mult_y[--i]) {
				nonlinear |= (1 << i);
				val -= st->info->mot_det_mult_y[i];
			}
	} else {
		i = ARRAY_SIZE(st->info->mot_det_mult_xz);
		while (i > 0)
			if (val >= st->info->mot_det_mult_xz[--i]) {
				nonlinear |= (1 << i);
				val -= st->info->mot_det_mult_xz[i];
			}
	}

	mutex_lock(&st->lock);
	ret = sca3000_write_ctrl_reg(st, sca3000_addresses[num][1], nonlinear);
	mutex_unlock(&st->lock);

	return ret;
}

static struct attribute *sca3000_attributes[] = {
	&iio_dev_attr_revision.dev_attr.attr,
	&iio_dev_attr_measurement_mode_available.dev_attr.attr,
	&iio_dev_attr_measurement_mode.dev_attr.attr,
	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
	&iio_dev_attr_sampling_frequency.dev_attr.attr,
	NULL,
};

static const struct attribute_group sca3000_attribute_group = {
	.attrs = sca3000_attributes,
};

/**
 * sca3000_event_handler() - handling ring and non ring events
 *
 * Ring related interrupt handler. Depending on event, push to
 * the ring buffer event chrdev or the event one.
 *
 * This function is complicated by the fact that the devices can signify ring
 * and non ring events via the same interrupt line and they can only
 * be distinguished via a read of the relevant status register.
 **/
static irqreturn_t sca3000_event_handler(int irq, void *private)
{
	struct iio_dev *indio_dev = private;
	struct sca3000_state *st = iio_priv(indio_dev);
	int ret, val;
	s64 last_timestamp = iio_get_time_ns();

	/*
	 * Could lead if badly timed to an extra read of status reg,
	 * but ensures no interrupt is missed.
	 */
	mutex_lock(&st->lock);
	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_INT_STATUS, 1);
	val = st->rx[0];
	mutex_unlock(&st->lock);
	if (ret)
		goto done;

	sca3000_ring_int_process(val, indio_dev->buffer);

	if (val & SCA3000_INT_STATUS_FREE_FALL)
		iio_push_event(indio_dev,
			       IIO_MOD_EVENT_CODE(IIO_ACCEL,
						  0,
						  IIO_MOD_X_AND_Y_AND_Z,
						  IIO_EV_TYPE_MAG,
						  IIO_EV_DIR_FALLING),
			       last_timestamp);

	if (val & SCA3000_INT_STATUS_Y_TRIGGER)
		iio_push_event(indio_dev,
			       IIO_MOD_EVENT_CODE(IIO_ACCEL,
						  0,
						  IIO_MOD_Y,
						  IIO_EV_TYPE_MAG,
						  IIO_EV_DIR_RISING),
			       last_timestamp);

	if (val & SCA3000_INT_STATUS_X_TRIGGER)
		iio_push_event(indio_dev,
			       IIO_MOD_EVENT_CODE(IIO_ACCEL,
						  0,
						  IIO_MOD_X,
						  IIO_EV_TYPE_MAG,
						  IIO_EV_DIR_RISING),
			       last_timestamp);

	if (val & SCA3000_INT_STATUS_Z_TRIGGER)
		iio_push_event(indio_dev,
			       IIO_MOD_EVENT_CODE(IIO_ACCEL,
						  0,
						  IIO_MOD_Z,
						  IIO_EV_TYPE_MAG,
						  IIO_EV_DIR_RISING),
			       last_timestamp);

done:
	return IRQ_HANDLED;
}

/**
 * sca3000_read_event_config() what events are enabled
 **/
static int sca3000_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 sca3000_state *st = iio_priv(indio_dev);
	int ret;
	u8 protect_mask = 0x03;
	int num = chan->channel2;

	/* read current value of mode register */
	mutex_lock(&st->lock);
	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
	if (ret)
		goto error_ret;

	if ((st->rx[0] & protect_mask) != SCA3000_MEAS_MODE_MOT_DET) {
		ret = 0;
	} else {
		ret = sca3000_read_ctrl_reg(st, SCA3000_REG_CTRL_SEL_MD_CTRL);
		if (ret < 0)
			goto error_ret;
		/* only supporting logical or's for now */
		ret = !!(ret & sca3000_addresses[num][2]);
	}
error_ret:
	mutex_unlock(&st->lock);

	return ret;
}

/**
 * sca3000_query_free_fall_mode() is free fall mode enabled
 **/
static ssize_t sca3000_query_free_fall_mode(struct device *dev,
					    struct device_attribute *attr,
					    char *buf)
{
	int ret;
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct sca3000_state *st = iio_priv(indio_dev);
	int val;

	mutex_lock(&st->lock);
	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
	val = st->rx[0];
	mutex_unlock(&st->lock);
	if (ret < 0)
		return ret;
	return sprintf(buf, "%d\n", !!(val & SCA3000_FREE_FALL_DETECT));
}

/**
 * sca3000_set_free_fall_mode() simple on off control for free fall int
 *
 * In these chips the free fall detector should send an interrupt if
 * the device falls more than 25cm.  This has not been tested due
 * to fragile wiring.
 **/
static ssize_t sca3000_set_free_fall_mode(struct device *dev,
					  struct device_attribute *attr,
					  const char *buf,
					  size_t len)
{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct sca3000_state *st = iio_priv(indio_dev);
	u8 val;
	int ret;
	u8 protect_mask = SCA3000_FREE_FALL_DETECT;

	mutex_lock(&st->lock);
	ret = kstrtou8(buf, 10, &val);
	if (ret)
		goto error_ret;

	/* read current value of mode register */
	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
	if (ret)
		goto error_ret;

	/* if off and should be on */
	if (val && !(st->rx[0] & protect_mask))
		ret = sca3000_write_reg(st, SCA3000_REG_ADDR_MODE,
					(st->rx[0] | SCA3000_FREE_FALL_DETECT));
	/* if on and should be off */
	else if (!val && (st->rx[0] & protect_mask))
		ret = sca3000_write_reg(st, SCA3000_REG_ADDR_MODE,
					(st->rx[0] & ~protect_mask));
error_ret:
	mutex_unlock(&st->lock);

	return ret ? ret : len;
}

/**
 * sca3000_write_event_config() simple on off control for motion detector
 *
 * This is a per axis control, but enabling any will result in the
 * motion detector unit being enabled.
 * N.B. enabling motion detector stops normal data acquisition.
 * There is a complexity in knowing which mode to return to when
 * this mode is disabled.  Currently normal mode is assumed.
 **/
static int sca3000_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 sca3000_state *st = iio_priv(indio_dev);
	int ret, ctrlval;
	u8 protect_mask = 0x03;
	int num = chan->channel2;

	mutex_lock(&st->lock);
	/*
	 * First read the motion detector config to find out if
	 * this axis is on
	 */
	ret = sca3000_read_ctrl_reg(st, SCA3000_REG_CTRL_SEL_MD_CTRL);
	if (ret < 0)
		goto exit_point;
	ctrlval = ret;
	/* if off and should be on */
	if (state && !(ctrlval & sca3000_addresses[num][2])) {
		ret = sca3000_write_ctrl_reg(st,
					     SCA3000_REG_CTRL_SEL_MD_CTRL,
					     ctrlval |
					     sca3000_addresses[num][2]);
		if (ret)
			goto exit_point;
		st->mo_det_use_count++;
	} else if (!state && (ctrlval & sca3000_addresses[num][2])) {
		ret = sca3000_write_ctrl_reg(st,
					     SCA3000_REG_CTRL_SEL_MD_CTRL,
					     ctrlval &
					     ~(sca3000_addresses[num][2]));
		if (ret)
			goto exit_point;
		st->mo_det_use_count--;
	}

	/* read current value of mode register */
	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
	if (ret)
		goto exit_point;
	/* if off and should be on */
	if ((st->mo_det_use_count) &&
	    ((st->rx[0] & protect_mask) != SCA3000_MEAS_MODE_MOT_DET))
		ret = sca3000_write_reg(st, SCA3000_REG_ADDR_MODE,
					(st->rx[0] & ~protect_mask)
					| SCA3000_MEAS_MODE_MOT_DET);
	/* if on and should be off */
	else if (!(st->mo_det_use_count) &&
		 ((st->rx[0] & protect_mask) == SCA3000_MEAS_MODE_MOT_DET))
		ret = sca3000_write_reg(st, SCA3000_REG_ADDR_MODE,
					(st->rx[0] & ~protect_mask));
exit_point:
	mutex_unlock(&st->lock);

	return ret;
}

/* Free fall detector related event attribute */
static IIO_DEVICE_ATTR_NAMED(accel_xayaz_mag_falling_en,
			     in_accel_x & y & z_mag_falling_en,
			     S_IRUGO | S_IWUSR,
			     sca3000_query_free_fall_mode,
			     sca3000_set_free_fall_mode,
			     0);

static IIO_CONST_ATTR_NAMED(accel_xayaz_mag_falling_period,
			    in_accel_x & y & z_mag_falling_period,
			    "0.226");

static struct attribute *sca3000_event_attributes[] = {
	&iio_dev_attr_accel_xayaz_mag_falling_en.dev_attr.attr,
	&iio_const_attr_accel_xayaz_mag_falling_period.dev_attr.attr,
	NULL,
};

static struct attribute_group sca3000_event_attribute_group = {
	.attrs = sca3000_event_attributes,
	.name = "events",
};

/**
 * sca3000_clean_setup() get the device into a predictable state
 *
 * Devices use flash memory to store many of the register values
 * and hence can come up in somewhat unpredictable states.
 * Hence reset everything on driver load.
 **/
static int sca3000_clean_setup(struct sca3000_state *st)
{
	int ret;

	mutex_lock(&st->lock);
	/* Ensure all interrupts have been acknowledged */
	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_INT_STATUS, 1);
	if (ret)
		goto error_ret;

	/* Turn off all motion detection channels */
	ret = sca3000_read_ctrl_reg(st, SCA3000_REG_CTRL_SEL_MD_CTRL);
	if (ret < 0)
		goto error_ret;
	ret = sca3000_write_ctrl_reg(st, SCA3000_REG_CTRL_SEL_MD_CTRL,
				     ret & SCA3000_MD_CTRL_PROT_MASK);
	if (ret)
		goto error_ret;

	/* Disable ring buffer */
	ret = sca3000_read_ctrl_reg(st, SCA3000_REG_CTRL_SEL_OUT_CTRL);
	ret = sca3000_write_ctrl_reg(st, SCA3000_REG_CTRL_SEL_OUT_CTRL,
				     (ret & SCA3000_OUT_CTRL_PROT_MASK)
				     | SCA3000_OUT_CTRL_BUF_X_EN
				     | SCA3000_OUT_CTRL_BUF_Y_EN
				     | SCA3000_OUT_CTRL_BUF_Z_EN
				     | SCA3000_OUT_CTRL_BUF_DIV_4);
	if (ret)
		goto error_ret;
	/* Enable interrupts, relevant to mode and set up as active low */
	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_INT_MASK, 1);
	if (ret)
		goto error_ret;
	ret = sca3000_write_reg(st,
				SCA3000_REG_ADDR_INT_MASK,
				(ret & SCA3000_INT_MASK_PROT_MASK)
				| SCA3000_INT_MASK_ACTIVE_LOW);
	if (ret)
		goto error_ret;
	/*
	 * Select normal measurement mode, free fall off, ring off
	 * Ring in 12 bit mode - it is fine to overwrite reserved bits 3,5
	 * as that occurs in one of the example on the datasheet
	 */
	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_MODE, 1);
	if (ret)
		goto error_ret;
	ret = sca3000_write_reg(st, SCA3000_REG_ADDR_MODE,
				(st->rx[0] & SCA3000_MODE_PROT_MASK));
	st->bpse = 11;

error_ret:
	mutex_unlock(&st->lock);
	return ret;
}

static const struct iio_info sca3000_info = {
	.attrs = &sca3000_attribute_group,
	.read_raw = &sca3000_read_raw,
	.event_attrs = &sca3000_event_attribute_group,
	.read_event_value = &sca3000_read_thresh,
	.write_event_value = &sca3000_write_thresh,
	.read_event_config = &sca3000_read_event_config,
	.write_event_config = &sca3000_write_event_config,
	.driver_module = THIS_MODULE,
};

static int sca3000_probe(struct spi_device *spi)
{
	int ret;
	struct sca3000_state *st;
	struct iio_dev *indio_dev;

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

	st = iio_priv(indio_dev);
	spi_set_drvdata(spi, indio_dev);
	st->us = spi;
	mutex_init(&st->lock);
	st->info = &sca3000_spi_chip_info_tbl[spi_get_device_id(spi)
					      ->driver_data];

	indio_dev->dev.parent = &spi->dev;
	indio_dev->name = spi_get_device_id(spi)->name;
	indio_dev->info = &sca3000_info;
	if (st->info->temp_output) {
		indio_dev->channels = sca3000_channels_with_temp;
		indio_dev->num_channels =
			ARRAY_SIZE(sca3000_channels_with_temp);
	} else {
		indio_dev->channels = sca3000_channels;
		indio_dev->num_channels = ARRAY_SIZE(sca3000_channels);
	}
	indio_dev->modes = INDIO_DIRECT_MODE;

	sca3000_configure_ring(indio_dev);
	ret = iio_device_register(indio_dev);
	if (ret < 0)
		return ret;

	if (spi->irq) {
		ret = request_threaded_irq(spi->irq,
					   NULL,
					   &sca3000_event_handler,
					   IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
					   "sca3000",
					   indio_dev);
		if (ret)
			goto error_unregister_dev;
	}
	sca3000_register_ring_funcs(indio_dev);
	ret = sca3000_clean_setup(st);
	if (ret)
		goto error_free_irq;
	return 0;

error_free_irq:
	if (spi->irq)
		free_irq(spi->irq, indio_dev);
error_unregister_dev:
	iio_device_unregister(indio_dev);
	return ret;
}

static int sca3000_stop_all_interrupts(struct sca3000_state *st)
{
	int ret;

	mutex_lock(&st->lock);
	ret = sca3000_read_data_short(st, SCA3000_REG_ADDR_INT_MASK, 1);
	if (ret)
		goto error_ret;
	ret = sca3000_write_reg(st, SCA3000_REG_ADDR_INT_MASK,
				(st->rx[0] &
				 ~(SCA3000_INT_MASK_RING_THREE_QUARTER |
				   SCA3000_INT_MASK_RING_HALF |
				   SCA3000_INT_MASK_ALL_INTS)));
error_ret:
	mutex_unlock(&st->lock);
	return ret;
}

static int sca3000_remove(struct spi_device *spi)
{
	struct iio_dev *indio_dev = spi_get_drvdata(spi);
	struct sca3000_state *st = iio_priv(indio_dev);

	/* Must ensure no interrupts can be generated after this! */
	sca3000_stop_all_interrupts(st);
	if (spi->irq)
		free_irq(spi->irq, indio_dev);
	iio_device_unregister(indio_dev);
	sca3000_unconfigure_ring(indio_dev);

	return 0;
}

static const struct spi_device_id sca3000_id[] = {
	{"sca3000_d01", d01},
	{"sca3000_e02", e02},
	{"sca3000_e04", e04},
	{"sca3000_e05", e05},
	{}
};
MODULE_DEVICE_TABLE(spi, sca3000_id);

static struct spi_driver sca3000_driver = {
	.driver = {
		.name = "sca3000",
	},
	.probe = sca3000_probe,
	.remove = sca3000_remove,
	.id_table = sca3000_id,
};
module_spi_driver(sca3000_driver);

MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
MODULE_DESCRIPTION("VTI SCA3000 Series Accelerometers SPI driver");
MODULE_LICENSE("GPL v2");