summaryrefslogtreecommitdiffstats
path: root/drivers/iio/adc/twl6030-gpadc.c
blob: df12c57e6ce07a700d211b81c9b5d3c9c15ff2d3 (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
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
/*
 * TWL6030 GPADC module driver
 *
 * Copyright (C) 2009-2013 Texas Instruments Inc.
 * Nishant Kamat <nskamat@ti.com>
 * Balaji T K <balajitk@ti.com>
 * Graeme Gregory <gg@slimlogic.co.uk>
 * Girish S Ghongdemath <girishsg@ti.com>
 * Ambresh K <ambresh@ti.com>
 * Oleksandr Kozaruk <oleksandr.kozaruk@ti.com
 *
 * Based on twl4030-madc.c
 * Copyright (C) 2008 Nokia Corporation
 * Mikko Ylinen <mikko.k.ylinen@nokia.com>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 */
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/of_platform.h>
#include <linux/i2c/twl.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>

#define DRIVER_NAME		"twl6030_gpadc"

/*
 * twl6030 per TRM has 17 channels, and twl6032 has 19 channels
 * 2 test network channels are not used,
 * 2 die temperature channels are not used either, as it is not
 * defined how to convert ADC value to temperature
 */
#define TWL6030_GPADC_USED_CHANNELS		13
#define TWL6030_GPADC_MAX_CHANNELS		15
#define TWL6032_GPADC_USED_CHANNELS		15
#define TWL6032_GPADC_MAX_CHANNELS		19
#define TWL6030_GPADC_NUM_TRIM_REGS		16

#define TWL6030_GPADC_CTRL_P1			0x05

#define TWL6032_GPADC_GPSELECT_ISB		0x07
#define TWL6032_GPADC_CTRL_P1			0x08

#define TWL6032_GPADC_GPCH0_LSB			0x0d
#define TWL6032_GPADC_GPCH0_MSB			0x0e

#define TWL6030_GPADC_CTRL_P1_SP1		BIT(3)

#define TWL6030_GPADC_GPCH0_LSB			(0x29)

#define TWL6030_GPADC_RT_SW1_EOC_MASK		BIT(5)

#define TWL6030_GPADC_TRIM1			0xCD

#define TWL6030_REG_TOGGLE1			0x90
#define TWL6030_GPADCS				BIT(1)
#define TWL6030_GPADCR				BIT(0)

/**
 * struct twl6030_chnl_calib - channel calibration
 * @gain:		slope coefficient for ideal curve
 * @gain_error:		gain error
 * @offset_error:	offset of the real curve
 */
struct twl6030_chnl_calib {
	s32 gain;
	s32 gain_error;
	s32 offset_error;
};

/**
 * struct twl6030_ideal_code - GPADC calibration parameters
 * GPADC is calibrated in two points: close to the beginning and
 * to the and of the measurable input range
 *
 * @channel:	channel number
 * @code1:	ideal code for the input at the beginning
 * @code2:	ideal code for at the end of the range
 * @volt1:	voltage input at the beginning(low voltage)
 * @volt2:	voltage input at the end(high voltage)
 */
struct twl6030_ideal_code {
	int channel;
	u16 code1;
	u16 code2;
	u16 volt1;
	u16 volt2;
};

struct twl6030_gpadc_data;

/**
 * struct twl6030_gpadc_platform_data - platform specific data
 * @nchannels:		number of GPADC channels
 * @iio_channels:	iio channels
 * @twl6030_ideal:	pointer to calibration parameters
 * @start_conversion:	pointer to ADC start conversion function
 * @channel_to_reg	pointer to ADC function to convert channel to
 *			register address for reading conversion result
 * @calibrate:		pointer to calibration function
 */
struct twl6030_gpadc_platform_data {
	const int nchannels;
	const struct iio_chan_spec *iio_channels;
	const struct twl6030_ideal_code *ideal;
	int (*start_conversion)(int channel);
	u8 (*channel_to_reg)(int channel);
	int (*calibrate)(struct twl6030_gpadc_data *gpadc);
};

/**
 * struct twl6030_gpadc_data - GPADC data
 * @dev:		device pointer
 * @lock:		mutual exclusion lock for the structure
 * @irq_complete:	completion to signal end of conversion
 * @twl6030_cal_tbl:	pointer to calibration data for each
 *			channel with gain error and offset
 * @pdata:		pointer to device specific data
 */
struct twl6030_gpadc_data {
	struct device	*dev;
	struct mutex	lock;
	struct completion	irq_complete;
	struct twl6030_chnl_calib	*twl6030_cal_tbl;
	const struct twl6030_gpadc_platform_data *pdata;
};

/*
 * channels 11, 12, 13, 15 and 16 have no calibration data
 * calibration offset is same for channels 1, 3, 4, 5
 *
 * The data is taken from GPADC_TRIM registers description.
 * GPADC_TRIM registers keep difference between the code measured
 * at volt1 and volt2 input voltages and corresponding code1 and code2
 */
static const struct twl6030_ideal_code
	twl6030_ideal[TWL6030_GPADC_USED_CHANNELS] = {
	[0] = { /* ch 0, external, battery type, resistor value */
		.channel = 0,
		.code1 = 116,
		.code2 = 745,
		.volt1 = 141,
		.volt2 = 910,
	},
	[1] = { /* ch 1, external, battery temperature, NTC resistor value */
		.channel = 1,
		.code1 = 82,
		.code2 = 900,
		.volt1 = 100,
		.volt2 = 1100,
	},
	[2] = { /* ch 2, external, audio accessory/general purpose */
		.channel = 2,
		.code1 = 55,
		.code2 = 818,
		.volt1 = 101,
		.volt2 = 1499,
	},
	[3] = { /* ch 3, external, general purpose */
		.channel = 3,
		.code1 = 82,
		.code2 = 900,
		.volt1 = 100,
		.volt2 = 1100,
	},
	[4] = { /* ch 4, external, temperature measurement/general purpose */
		.channel = 4,
		.code1 = 82,
		.code2 = 900,
		.volt1 = 100,
		.volt2 = 1100,
	},
	[5] = { /* ch 5, external, general purpose */
		.channel = 5,
		.code1 = 82,
		.code2 = 900,
		.volt1 = 100,
		.volt2 = 1100,
	},
	[6] = { /* ch 6, external, general purpose */
		.channel = 6,
		.code1 = 82,
		.code2 = 900,
		.volt1 = 100,
		.volt2 = 1100,
	},
	[7] = { /* ch 7, internal, main battery */
		.channel = 7,
		.code1 = 614,
		.code2 = 941,
		.volt1 = 3001,
		.volt2 = 4599,
	},
	[8] = { /* ch 8, internal, backup battery */
		.channel = 8,
		.code1 = 82,
		.code2 = 688,
		.volt1 = 501,
		.volt2 = 4203,
	},
	[9] = { /* ch 9, internal, external charger input */
		.channel = 9,
		.code1 = 182,
		.code2 = 818,
		.volt1 = 2001,
		.volt2 = 8996,
	},
	[10] = { /* ch 10, internal, VBUS */
		.channel = 10,
		.code1 = 149,
		.code2 = 818,
		.volt1 = 1001,
		.volt2 = 5497,
	},
	[11] = { /* ch 11, internal, VBUS charging current */
		.channel = 11,
	},
		/* ch 12, internal, Die temperature */
		/* ch 13, internal, Die temperature */
	[12] = { /* ch 14, internal, USB ID line */
		.channel = 14,
		.code1 = 48,
		.code2 = 714,
		.volt1 = 323,
		.volt2 = 4800,
	},
};

static const struct twl6030_ideal_code
			twl6032_ideal[TWL6032_GPADC_USED_CHANNELS] = {
	[0] = { /* ch 0, external, battery type, resistor value */
		.channel = 0,
		.code1 = 1441,
		.code2 = 3276,
		.volt1 = 440,
		.volt2 = 1000,
	},
	[1] = { /* ch 1, external, battery temperature, NTC resistor value */
		.channel = 1,
		.code1 = 1441,
		.code2 = 3276,
		.volt1 = 440,
		.volt2 = 1000,
	},
	[2] = { /* ch 2, external, audio accessory/general purpose */
		.channel = 2,
		.code1 = 1441,
		.code2 = 3276,
		.volt1 = 660,
		.volt2 = 1500,
	},
	[3] = { /* ch 3, external, temperature with external diode/general
								purpose */
		.channel = 3,
		.code1 = 1441,
		.code2 = 3276,
		.volt1 = 440,
		.volt2 = 1000,
	},
	[4] = { /* ch 4, external, temperature measurement/general purpose */
		.channel = 4,
		.code1 = 1441,
		.code2 = 3276,
		.volt1 = 440,
		.volt2 = 1000,
	},
	[5] = { /* ch 5, external, general purpose */
		.channel = 5,
		.code1 = 1441,
		.code2 = 3276,
		.volt1 = 440,
		.volt2 = 1000,
	},
	[6] = { /* ch 6, external, general purpose */
		.channel = 6,
		.code1 = 1441,
		.code2 = 3276,
		.volt1 = 440,
		.volt2 = 1000,
	},
	[7] = { /* ch7, internal, system supply */
		.channel = 7,
		.code1 = 1441,
		.code2 = 3276,
		.volt1 = 2200,
		.volt2 = 5000,
	},
	[8] = { /* ch8, internal, backup battery */
		.channel = 8,
		.code1 = 1441,
		.code2 = 3276,
		.volt1 = 2200,
		.volt2 = 5000,
	},
	[9] = { /* ch 9, internal, external charger input */
		.channel = 9,
		.code1 = 1441,
		.code2 = 3276,
		.volt1 = 3960,
		.volt2 = 9000,
	},
	[10] = { /* ch10, internal, VBUS */
		.channel = 10,
		.code1 = 150,
		.code2 = 751,
		.volt1 = 1000,
		.volt2 = 5000,
	},
	[11] = { /* ch 11, internal, VBUS DC-DC output current */
		.channel = 11,
		.code1 = 1441,
		.code2 = 3276,
		.volt1 = 660,
		.volt2 = 1500,
	},
		/* ch 12, internal, Die temperature */
		/* ch 13, internal, Die temperature */
	[12] = { /* ch 14, internal, USB ID line */
		.channel = 14,
		.code1 = 1441,
		.code2 = 3276,
		.volt1 = 2420,
		.volt2 = 5500,
	},
		/* ch 15, internal, test network */
		/* ch 16, internal, test network */
	[13] = { /* ch 17, internal, battery charging current */
		.channel = 17,
	},
	[14] = { /* ch 18, internal, battery voltage */
		.channel = 18,
		.code1 = 1441,
		.code2 = 3276,
		.volt1 = 2200,
		.volt2 = 5000,
	},
};

static inline int twl6030_gpadc_write(u8 reg, u8 val)
{
	return twl_i2c_write_u8(TWL6030_MODULE_GPADC, val, reg);
}

static inline int twl6030_gpadc_read(u8 reg, u8 *val)
{

	return twl_i2c_read(TWL6030_MODULE_GPADC, val, reg, 2);
}

static int twl6030_gpadc_enable_irq(u8 mask)
{
	int ret;

	ret = twl6030_interrupt_unmask(mask, REG_INT_MSK_LINE_B);
	if (ret < 0)
		return ret;

	ret = twl6030_interrupt_unmask(mask, REG_INT_MSK_STS_B);

	return ret;
}

static void twl6030_gpadc_disable_irq(u8 mask)
{
	twl6030_interrupt_mask(mask, REG_INT_MSK_LINE_B);
	twl6030_interrupt_mask(mask, REG_INT_MSK_STS_B);
}

static irqreturn_t twl6030_gpadc_irq_handler(int irq, void *indio_dev)
{
	struct twl6030_gpadc_data *gpadc = iio_priv(indio_dev);

	complete(&gpadc->irq_complete);

	return IRQ_HANDLED;
}

static int twl6030_start_conversion(int channel)
{
	return twl6030_gpadc_write(TWL6030_GPADC_CTRL_P1,
					TWL6030_GPADC_CTRL_P1_SP1);
}

static int twl6032_start_conversion(int channel)
{
	int ret;

	ret = twl6030_gpadc_write(TWL6032_GPADC_GPSELECT_ISB, channel);
	if (ret)
		return ret;

	return twl6030_gpadc_write(TWL6032_GPADC_CTRL_P1,
						TWL6030_GPADC_CTRL_P1_SP1);
}

static u8 twl6030_channel_to_reg(int channel)
{
	return TWL6030_GPADC_GPCH0_LSB + 2 * channel;
}

static u8 twl6032_channel_to_reg(int channel)
{
	/*
	 * for any prior chosen channel, when the conversion is ready
	 * the result is avalable in GPCH0_LSB, GPCH0_MSB.
	 */

	return TWL6032_GPADC_GPCH0_LSB;
}

static int twl6030_gpadc_lookup(const struct twl6030_ideal_code *ideal,
		int channel, int size)
{
	int i;

	for (i = 0; i < size; i++)
		if (ideal[i].channel == channel)
			break;

	return i;
}

static int twl6030_channel_calibrated(const struct twl6030_gpadc_platform_data
		*pdata, int channel)
{
	const struct twl6030_ideal_code *ideal = pdata->ideal;
	int i;

	i = twl6030_gpadc_lookup(ideal, channel, pdata->nchannels);
	/* not calibrated channels have 0 in all structure members */
	return pdata->ideal[i].code2;
}

static int twl6030_gpadc_make_correction(struct twl6030_gpadc_data *gpadc,
		int channel, int raw_code)
{
	const struct twl6030_ideal_code *ideal = gpadc->pdata->ideal;
	int corrected_code;
	int i;

	i = twl6030_gpadc_lookup(ideal, channel, gpadc->pdata->nchannels);
	corrected_code = ((raw_code * 1000) -
		gpadc->twl6030_cal_tbl[i].offset_error) /
		gpadc->twl6030_cal_tbl[i].gain_error;

	return corrected_code;
}

static int twl6030_gpadc_get_raw(struct twl6030_gpadc_data *gpadc,
		int channel, int *res)
{
	u8 reg = gpadc->pdata->channel_to_reg(channel);
	__le16 val;
	int raw_code;
	int ret;

	ret = twl6030_gpadc_read(reg, (u8 *)&val);
	if (ret) {
		dev_dbg(gpadc->dev, "unable to read register 0x%X\n", reg);
		return ret;
	}

	raw_code = le16_to_cpu(val);
	dev_dbg(gpadc->dev, "GPADC raw code: %d", raw_code);

	if (twl6030_channel_calibrated(gpadc->pdata, channel))
		*res = twl6030_gpadc_make_correction(gpadc, channel, raw_code);
	else
		*res = raw_code;

	return ret;
}

static int twl6030_gpadc_get_processed(struct twl6030_gpadc_data *gpadc,
		int channel, int *val)
{
	const struct twl6030_ideal_code *ideal = gpadc->pdata->ideal;
	int corrected_code;
	int channel_value;
	int i;
	int ret;

	ret = twl6030_gpadc_get_raw(gpadc, channel, &corrected_code);
	if (ret)
		return ret;

	i = twl6030_gpadc_lookup(ideal, channel, gpadc->pdata->nchannels);
	channel_value = corrected_code *
			gpadc->twl6030_cal_tbl[i].gain;

	/* Shift back into mV range */
	channel_value /= 1000;

	dev_dbg(gpadc->dev, "GPADC corrected code: %d", corrected_code);
	dev_dbg(gpadc->dev, "GPADC value: %d", channel_value);

	*val = channel_value;

	return ret;
}

static int twl6030_gpadc_read_raw(struct iio_dev *indio_dev,
			     const struct iio_chan_spec *chan,
			     int *val, int *val2, long mask)
{
	struct twl6030_gpadc_data *gpadc = iio_priv(indio_dev);
	int ret;
	long timeout;

	mutex_lock(&gpadc->lock);

	ret = gpadc->pdata->start_conversion(chan->channel);
	if (ret) {
		dev_err(gpadc->dev, "failed to start conversion\n");
		goto err;
	}
	/* wait for conversion to complete */
	timeout = wait_for_completion_interruptible_timeout(
				&gpadc->irq_complete, msecs_to_jiffies(5000));
	if (timeout == 0) {
		ret = -ETIMEDOUT;
		goto err;
	} else if (timeout < 0) {
		ret = -EINTR;
		goto err;
	}

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		ret = twl6030_gpadc_get_raw(gpadc, chan->channel, val);
		ret = ret ? -EIO : IIO_VAL_INT;
		break;

	case IIO_CHAN_INFO_PROCESSED:
		ret = twl6030_gpadc_get_processed(gpadc, chan->channel, val);
		ret = ret ? -EIO : IIO_VAL_INT;
		break;

	default:
		break;
	}
err:
	mutex_unlock(&gpadc->lock);

	return ret;
}

/*
 * The GPADC channels are calibrated using a two point calibration method.
 * The channels measured with two known values: volt1 and volt2, and
 * ideal corresponding output codes are known: code1, code2.
 * The difference(d1, d2) between ideal and measured codes stored in trim
 * registers.
 * The goal is to find offset and gain of the real curve for each calibrated
 * channel.
 * gain: k = 1 + ((d2 - d1) / (x2 - x1))
 * offset: b = d1 + (k - 1) * x1
 */
static void twl6030_calibrate_channel(struct twl6030_gpadc_data *gpadc,
		int channel, int d1, int d2)
{
	int b, k, gain, x1, x2, i;
	const struct twl6030_ideal_code *ideal = gpadc->pdata->ideal;

	i = twl6030_gpadc_lookup(ideal, channel, gpadc->pdata->nchannels);

	/* Gain */
	gain = ((ideal[i].volt2 - ideal[i].volt1) * 1000) /
		(ideal[i].code2 - ideal[i].code1);

	x1 = ideal[i].code1;
	x2 = ideal[i].code2;

	/* k - real curve gain */
	k = 1000 + (((d2 - d1) * 1000) / (x2 - x1));

	/* b - offset of the real curve gain */
	b = (d1 * 1000) - (k - 1000) * x1;

	gpadc->twl6030_cal_tbl[i].gain = gain;
	gpadc->twl6030_cal_tbl[i].gain_error = k;
	gpadc->twl6030_cal_tbl[i].offset_error = b;

	dev_dbg(gpadc->dev, "GPADC d1   for Chn: %d = %d\n", channel, d1);
	dev_dbg(gpadc->dev, "GPADC d2   for Chn: %d = %d\n", channel, d2);
	dev_dbg(gpadc->dev, "GPADC x1   for Chn: %d = %d\n", channel, x1);
	dev_dbg(gpadc->dev, "GPADC x2   for Chn: %d = %d\n", channel, x2);
	dev_dbg(gpadc->dev, "GPADC Gain for Chn: %d = %d\n", channel, gain);
	dev_dbg(gpadc->dev, "GPADC k    for Chn: %d = %d\n", channel, k);
	dev_dbg(gpadc->dev, "GPADC b    for Chn: %d = %d\n", channel, b);
}

static inline int twl6030_gpadc_get_trim_offset(s8 d)
{
	/*
	 * XXX NOTE!
	 * bit 0 - sign, bit 7 - reserved, 6..1 - trim value
	 * though, the documentation states that trim value
	 * is absolute value, the correct conversion results are
	 * obtained if the value is interpreted as 2's complement.
	 */
	__u32 temp = ((d & 0x7f) >> 1) | ((d & 1) << 6);

	return sign_extend32(temp, 6);
}

static int twl6030_calibration(struct twl6030_gpadc_data *gpadc)
{
	int ret;
	int chn;
	u8 trim_regs[TWL6030_GPADC_NUM_TRIM_REGS];
	s8 d1, d2;

	/*
	 * for calibration two measurements have been performed at
	 * factory, for some channels, during the production test and
	 * have been stored in registers. This two stored values are
	 * used to correct the measurements. The values represent
	 * offsets for the given input from the output on ideal curve.
	 */
	ret = twl_i2c_read(TWL6030_MODULE_ID2, trim_regs,
			TWL6030_GPADC_TRIM1, TWL6030_GPADC_NUM_TRIM_REGS);
	if (ret < 0) {
		dev_err(gpadc->dev, "calibration failed\n");
		return ret;
	}

	for (chn = 0; chn < TWL6030_GPADC_MAX_CHANNELS; chn++) {

		switch (chn) {
		case 0:
			d1 = trim_regs[0];
			d2 = trim_regs[1];
			break;
		case 1:
		case 3:
		case 4:
		case 5:
		case 6:
			d1 = trim_regs[4];
			d2 = trim_regs[5];
			break;
		case 2:
			d1 = trim_regs[12];
			d2 = trim_regs[13];
			break;
		case 7:
			d1 = trim_regs[6];
			d2 = trim_regs[7];
			break;
		case 8:
			d1 = trim_regs[2];
			d2 = trim_regs[3];
			break;
		case 9:
			d1 = trim_regs[8];
			d2 = trim_regs[9];
			break;
		case 10:
			d1 = trim_regs[10];
			d2 = trim_regs[11];
			break;
		case 14:
			d1 = trim_regs[14];
			d2 = trim_regs[15];
			break;
		default:
			continue;
		}

		d1 = twl6030_gpadc_get_trim_offset(d1);
		d2 = twl6030_gpadc_get_trim_offset(d2);

		twl6030_calibrate_channel(gpadc, chn, d1, d2);
	}

	return 0;
}

static int twl6032_get_trim_value(u8 *trim_regs, unsigned int reg0,
		unsigned int reg1, unsigned int mask0, unsigned int mask1,
		unsigned int shift0)
{
	int val;

	val = (trim_regs[reg0] & mask0) << shift0;
	val |= (trim_regs[reg1] & mask1) >> 1;
	if (trim_regs[reg1] & 0x01)
		val = -val;

	return val;
}

static int twl6032_calibration(struct twl6030_gpadc_data *gpadc)
{
	int chn, d1 = 0, d2 = 0, temp;
	u8 trim_regs[TWL6030_GPADC_NUM_TRIM_REGS];
	int ret;

	ret = twl_i2c_read(TWL6030_MODULE_ID2, trim_regs,
			TWL6030_GPADC_TRIM1, TWL6030_GPADC_NUM_TRIM_REGS);
	if (ret < 0) {
		dev_err(gpadc->dev, "calibration failed\n");
		return ret;
	}

	/*
	 * Loop to calculate the value needed for returning voltages from
	 * GPADC not values.
	 *
	 * gain is calculated to 3 decimal places fixed point.
	 */
	for (chn = 0; chn < TWL6032_GPADC_MAX_CHANNELS; chn++) {

		switch (chn) {
		case 0:
		case 1:
		case 2:
		case 3:
		case 4:
		case 5:
		case 6:
		case 11:
		case 14:
			d1 = twl6032_get_trim_value(trim_regs, 2, 0, 0x1f,
								0x06, 2);
			d2 = twl6032_get_trim_value(trim_regs, 3, 1, 0x3f,
								0x06, 2);
			break;
		case 8:
			temp = twl6032_get_trim_value(trim_regs, 2, 0, 0x1f,
								0x06, 2);
			d1 = temp + twl6032_get_trim_value(trim_regs, 7, 6,
								0x18, 0x1E, 1);

			temp = twl6032_get_trim_value(trim_regs, 3, 1, 0x3F,
								0x06, 2);
			d2 = temp + twl6032_get_trim_value(trim_regs, 9, 7,
								0x1F, 0x06, 2);
			break;
		case 9:
			temp = twl6032_get_trim_value(trim_regs, 2, 0, 0x1f,
								0x06, 2);
			d1 = temp + twl6032_get_trim_value(trim_regs, 13, 11,
								0x18, 0x1E, 1);

			temp = twl6032_get_trim_value(trim_regs, 3, 1, 0x3f,
								0x06, 2);
			d2 = temp + twl6032_get_trim_value(trim_regs, 15, 13,
								0x1F, 0x06, 1);
			break;
		case 10:
			d1 = twl6032_get_trim_value(trim_regs, 10, 8, 0x0f,
								0x0E, 3);
			d2 = twl6032_get_trim_value(trim_regs, 14, 12, 0x0f,
								0x0E, 3);
			break;
		case 7:
		case 18:
			temp = twl6032_get_trim_value(trim_regs, 2, 0, 0x1f,
								0x06, 2);

			d1 = (trim_regs[4] & 0x7E) >> 1;
			if (trim_regs[4] & 0x01)
				d1 = -d1;
			d1 += temp;

			temp = twl6032_get_trim_value(trim_regs, 3, 1, 0x3f,
								0x06, 2);

			d2 = (trim_regs[5] & 0xFE) >> 1;
			if (trim_regs[5] & 0x01)
				d2 = -d2;

			d2 += temp;
			break;
		default:
			/* No data for other channels */
			continue;
		}

		twl6030_calibrate_channel(gpadc, chn, d1, d2);
	}

	return 0;
}

#define TWL6030_GPADC_CHAN(chn, _type, chan_info) {	\
	.type = _type,					\
	.channel = chn,					\
	.info_mask_separate = BIT(chan_info),		\
	.indexed = 1,					\
}

static const struct iio_chan_spec twl6030_gpadc_iio_channels[] = {
	TWL6030_GPADC_CHAN(0, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
	TWL6030_GPADC_CHAN(1, IIO_TEMP, IIO_CHAN_INFO_RAW),
	TWL6030_GPADC_CHAN(2, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
	TWL6030_GPADC_CHAN(3, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
	TWL6030_GPADC_CHAN(4, IIO_TEMP, IIO_CHAN_INFO_RAW),
	TWL6030_GPADC_CHAN(5, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
	TWL6030_GPADC_CHAN(6, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
	TWL6030_GPADC_CHAN(7, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
	TWL6030_GPADC_CHAN(8, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
	TWL6030_GPADC_CHAN(9, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
	TWL6030_GPADC_CHAN(10, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
	TWL6030_GPADC_CHAN(11, IIO_VOLTAGE, IIO_CHAN_INFO_RAW),
	TWL6030_GPADC_CHAN(14, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
};

static const struct iio_chan_spec twl6032_gpadc_iio_channels[] = {
	TWL6030_GPADC_CHAN(0, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
	TWL6030_GPADC_CHAN(1, IIO_TEMP, IIO_CHAN_INFO_RAW),
	TWL6030_GPADC_CHAN(2, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
	TWL6030_GPADC_CHAN(3, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
	TWL6030_GPADC_CHAN(4, IIO_TEMP, IIO_CHAN_INFO_RAW),
	TWL6030_GPADC_CHAN(5, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
	TWL6030_GPADC_CHAN(6, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
	TWL6030_GPADC_CHAN(7, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
	TWL6030_GPADC_CHAN(8, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
	TWL6030_GPADC_CHAN(9, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
	TWL6030_GPADC_CHAN(10, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
	TWL6030_GPADC_CHAN(11, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
	TWL6030_GPADC_CHAN(14, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
	TWL6030_GPADC_CHAN(17, IIO_VOLTAGE, IIO_CHAN_INFO_RAW),
	TWL6030_GPADC_CHAN(18, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
};

static const struct iio_info twl6030_gpadc_iio_info = {
	.read_raw = &twl6030_gpadc_read_raw,
	.driver_module = THIS_MODULE,
};

static const struct twl6030_gpadc_platform_data twl6030_pdata = {
	.iio_channels = twl6030_gpadc_iio_channels,
	.nchannels = TWL6030_GPADC_USED_CHANNELS,
	.ideal = twl6030_ideal,
	.start_conversion = twl6030_start_conversion,
	.channel_to_reg = twl6030_channel_to_reg,
	.calibrate = twl6030_calibration,
};

static const struct twl6030_gpadc_platform_data twl6032_pdata = {
	.iio_channels = twl6032_gpadc_iio_channels,
	.nchannels = TWL6032_GPADC_USED_CHANNELS,
	.ideal = twl6032_ideal,
	.start_conversion = twl6032_start_conversion,
	.channel_to_reg = twl6032_channel_to_reg,
	.calibrate = twl6032_calibration,
};

static const struct of_device_id of_twl6030_match_tbl[] = {
	{
		.compatible = "ti,twl6030-gpadc",
		.data = &twl6030_pdata,
	},
	{
		.compatible = "ti,twl6032-gpadc",
		.data = &twl6032_pdata,
	},
	{ /* end */ }
};

static int twl6030_gpadc_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct twl6030_gpadc_data *gpadc;
	const struct twl6030_gpadc_platform_data *pdata;
	const struct of_device_id *match;
	struct iio_dev *indio_dev;
	int irq;
	int ret;

	match = of_match_device(of_twl6030_match_tbl, dev);
	if (!match)
		return -EINVAL;

	pdata = match->data;

	indio_dev = devm_iio_device_alloc(dev, sizeof(*gpadc));
	if (!indio_dev)
		return -ENOMEM;

	gpadc = iio_priv(indio_dev);

	gpadc->twl6030_cal_tbl = devm_kzalloc(dev,
					sizeof(*gpadc->twl6030_cal_tbl) *
					pdata->nchannels, GFP_KERNEL);
	if (!gpadc->twl6030_cal_tbl)
		return -ENOMEM;

	gpadc->dev = dev;
	gpadc->pdata = pdata;

	platform_set_drvdata(pdev, indio_dev);
	mutex_init(&gpadc->lock);
	init_completion(&gpadc->irq_complete);

	ret = pdata->calibrate(gpadc);
	if (ret < 0) {
		dev_err(&pdev->dev, "failed to read calibration registers\n");
		return ret;
	}

	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		dev_err(&pdev->dev, "failed to get irq\n");
		return irq;
	}

	ret = devm_request_threaded_irq(dev, irq, NULL,
				twl6030_gpadc_irq_handler,
				IRQF_ONESHOT, "twl6030_gpadc", indio_dev);

	ret = twl6030_gpadc_enable_irq(TWL6030_GPADC_RT_SW1_EOC_MASK);
	if (ret < 0) {
		dev_err(&pdev->dev, "failed to enable GPADC interrupt\n");
		return ret;
	}

	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, TWL6030_GPADCS,
					TWL6030_REG_TOGGLE1);
	if (ret < 0) {
		dev_err(&pdev->dev, "failed to enable GPADC module\n");
		return ret;
	}

	indio_dev->name = DRIVER_NAME;
	indio_dev->dev.parent = dev;
	indio_dev->info = &twl6030_gpadc_iio_info;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels = pdata->iio_channels;
	indio_dev->num_channels = pdata->nchannels;

	return iio_device_register(indio_dev);
}

static int twl6030_gpadc_remove(struct platform_device *pdev)
{
	struct iio_dev *indio_dev = platform_get_drvdata(pdev);

	twl6030_gpadc_disable_irq(TWL6030_GPADC_RT_SW1_EOC_MASK);
	iio_device_unregister(indio_dev);

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int twl6030_gpadc_suspend(struct device *pdev)
{
	int ret;

	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, TWL6030_GPADCR,
				TWL6030_REG_TOGGLE1);
	if (ret)
		dev_err(pdev, "error resetting GPADC (%d)!\n", ret);

	return 0;
};

static int twl6030_gpadc_resume(struct device *pdev)
{
	int ret;

	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, TWL6030_GPADCS,
				TWL6030_REG_TOGGLE1);
	if (ret)
		dev_err(pdev, "error setting GPADC (%d)!\n", ret);

	return 0;
};
#endif

static SIMPLE_DEV_PM_OPS(twl6030_gpadc_pm_ops, twl6030_gpadc_suspend,
					twl6030_gpadc_resume);

static struct platform_driver twl6030_gpadc_driver = {
	.probe		= twl6030_gpadc_probe,
	.remove		= twl6030_gpadc_remove,
	.driver		= {
		.name	= DRIVER_NAME,
		.pm	= &twl6030_gpadc_pm_ops,
		.of_match_table = of_twl6030_match_tbl,
	},
};

module_platform_driver(twl6030_gpadc_driver);

MODULE_ALIAS("platform:" DRIVER_NAME);
MODULE_AUTHOR("Balaji T K <balajitk@ti.com>");
MODULE_AUTHOR("Graeme Gregory <gg@slimlogic.co.uk>");
MODULE_AUTHOR("Oleksandr Kozaruk <oleksandr.kozaruk@ti.com");
MODULE_DESCRIPTION("twl6030 ADC driver");
MODULE_LICENSE("GPL");