summaryrefslogtreecommitdiffstats
path: root/drivers/iio/adc/at91_adc.c
blob: 17df74908db120a6e33e3f43a51fc4e67784da59 (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
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
/*
 * Driver for the ADC present in the Atmel AT91 evaluation boards.
 *
 * Copyright 2011 Free Electrons
 *
 * Licensed under the GPLv2 or later.
 */

#include <linux/bitmap.h>
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/wait.h>

#include <linux/platform_data/at91_adc.h>

#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>

#include <mach/at91_adc.h>

#define AT91_ADC_CHAN(st, ch) \
	(st->registers->channel_base + (ch * 4))
#define at91_adc_readl(st, reg) \
	(readl_relaxed(st->reg_base + reg))
#define at91_adc_writel(st, reg, val) \
	(writel_relaxed(val, st->reg_base + reg))

#define DRIVER_NAME		"at91_adc"
#define MAX_POS_BITS		12

#define TOUCH_SAMPLE_PERIOD_US		2000	/* 2ms */
#define TOUCH_PEN_DETECT_DEBOUNCE_US	200

struct at91_adc_caps {
	bool	has_ts;		/* Support touch screen */
	bool	has_tsmr;	/* only at91sam9x5, sama5d3 have TSMR reg */
	/*
	 * Numbers of sampling data will be averaged. Can be 0~3.
	 * Hardware can average (2 ^ ts_filter_average) sample data.
	 */
	u8	ts_filter_average;
	/* Pen Detection input pull-up resistor, can be 0~3 */
	u8	ts_pen_detect_sensitivity;

	/* startup time calculate function */
	u32 (*calc_startup_ticks)(u8 startup_time, u32 adc_clk_khz);

	u8	num_channels;
	struct at91_adc_reg_desc registers;
};

enum atmel_adc_ts_type {
	ATMEL_ADC_TOUCHSCREEN_NONE = 0,
	ATMEL_ADC_TOUCHSCREEN_4WIRE = 4,
	ATMEL_ADC_TOUCHSCREEN_5WIRE = 5,
};

struct at91_adc_state {
	struct clk		*adc_clk;
	u16			*buffer;
	unsigned long		channels_mask;
	struct clk		*clk;
	bool			done;
	int			irq;
	u16			last_value;
	struct mutex		lock;
	u8			num_channels;
	void __iomem		*reg_base;
	struct at91_adc_reg_desc *registers;
	u8			startup_time;
	u8			sample_hold_time;
	bool			sleep_mode;
	struct iio_trigger	**trig;
	struct at91_adc_trigger	*trigger_list;
	u32			trigger_number;
	bool			use_external;
	u32			vref_mv;
	u32			res;		/* resolution used for convertions */
	bool			low_res;	/* the resolution corresponds to the lowest one */
	wait_queue_head_t	wq_data_avail;
	struct at91_adc_caps	*caps;

	/*
	 * Following ADC channels are shared by touchscreen:
	 *
	 * CH0 -- Touch screen XP/UL
	 * CH1 -- Touch screen XM/UR
	 * CH2 -- Touch screen YP/LL
	 * CH3 -- Touch screen YM/Sense
	 * CH4 -- Touch screen LR(5-wire only)
	 *
	 * The bitfields below represents the reserved channel in the
	 * touchscreen mode.
	 */
#define CHAN_MASK_TOUCHSCREEN_4WIRE	(0xf << 0)
#define CHAN_MASK_TOUCHSCREEN_5WIRE	(0x1f << 0)
	enum atmel_adc_ts_type	touchscreen_type;
	struct input_dev	*ts_input;

	u16			ts_sample_period_val;
	u32			ts_pressure_threshold;
};

static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
{
	struct iio_poll_func *pf = p;
	struct iio_dev *idev = pf->indio_dev;
	struct at91_adc_state *st = iio_priv(idev);
	int i, j = 0;

	for (i = 0; i < idev->masklength; i++) {
		if (!test_bit(i, idev->active_scan_mask))
			continue;
		st->buffer[j] = at91_adc_readl(st, AT91_ADC_CHAN(st, i));
		j++;
	}

	iio_push_to_buffers_with_timestamp(idev, st->buffer, pf->timestamp);

	iio_trigger_notify_done(idev->trig);

	/* Needed to ACK the DRDY interruption */
	at91_adc_readl(st, AT91_ADC_LCDR);

	enable_irq(st->irq);

	return IRQ_HANDLED;
}

/* Handler for classic adc channel eoc trigger */
void handle_adc_eoc_trigger(int irq, struct iio_dev *idev)
{
	struct at91_adc_state *st = iio_priv(idev);

	if (iio_buffer_enabled(idev)) {
		disable_irq_nosync(irq);
		iio_trigger_poll(idev->trig, iio_get_time_ns());
	} else {
		st->last_value = at91_adc_readl(st, AT91_ADC_LCDR);
		st->done = true;
		wake_up_interruptible(&st->wq_data_avail);
	}
}

static int at91_ts_sample(struct at91_adc_state *st)
{
	unsigned int xscale, yscale, reg, z1, z2;
	unsigned int x, y, pres, xpos, ypos;
	unsigned int rxp = 1;
	unsigned int factor = 1000;
	struct iio_dev *idev = iio_priv_to_dev(st);

	unsigned int xyz_mask_bits = st->res;
	unsigned int xyz_mask = (1 << xyz_mask_bits) - 1;

	/* calculate position */
	/* x position = (x / xscale) * max, max = 2^MAX_POS_BITS - 1 */
	reg = at91_adc_readl(st, AT91_ADC_TSXPOSR);
	xpos = reg & xyz_mask;
	x = (xpos << MAX_POS_BITS) - xpos;
	xscale = (reg >> 16) & xyz_mask;
	if (xscale == 0) {
		dev_err(&idev->dev, "Error: xscale == 0!\n");
		return -1;
	}
	x /= xscale;

	/* y position = (y / yscale) * max, max = 2^MAX_POS_BITS - 1 */
	reg = at91_adc_readl(st, AT91_ADC_TSYPOSR);
	ypos = reg & xyz_mask;
	y = (ypos << MAX_POS_BITS) - ypos;
	yscale = (reg >> 16) & xyz_mask;
	if (yscale == 0) {
		dev_err(&idev->dev, "Error: yscale == 0!\n");
		return -1;
	}
	y /= yscale;

	/* calculate the pressure */
	reg = at91_adc_readl(st, AT91_ADC_TSPRESSR);
	z1 = reg & xyz_mask;
	z2 = (reg >> 16) & xyz_mask;

	if (z1 != 0)
		pres = rxp * (x * factor / 1024) * (z2 * factor / z1 - factor)
			/ factor;
	else
		pres = st->ts_pressure_threshold;	/* no pen contacted */

	dev_dbg(&idev->dev, "xpos = %d, xscale = %d, ypos = %d, yscale = %d, z1 = %d, z2 = %d, press = %d\n",
				xpos, xscale, ypos, yscale, z1, z2, pres);

	if (pres < st->ts_pressure_threshold) {
		dev_dbg(&idev->dev, "x = %d, y = %d, pressure = %d\n",
					x, y, pres / factor);
		input_report_abs(st->ts_input, ABS_X, x);
		input_report_abs(st->ts_input, ABS_Y, y);
		input_report_abs(st->ts_input, ABS_PRESSURE, pres);
		input_report_key(st->ts_input, BTN_TOUCH, 1);
		input_sync(st->ts_input);
	} else {
		dev_dbg(&idev->dev, "pressure too low: not reporting\n");
	}

	return 0;
}

static irqreturn_t at91_adc_interrupt(int irq, void *private)
{
	struct iio_dev *idev = private;
	struct at91_adc_state *st = iio_priv(idev);
	u32 status = at91_adc_readl(st, st->registers->status_register);
	const uint32_t ts_data_irq_mask =
		AT91_ADC_IER_XRDY |
		AT91_ADC_IER_YRDY |
		AT91_ADC_IER_PRDY;

	if (status & st->registers->drdy_mask)
		handle_adc_eoc_trigger(irq, idev);

	if (status & AT91_ADC_IER_PEN) {
		at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
		at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_NOPEN |
			ts_data_irq_mask);
		/* Set up period trigger for sampling */
		at91_adc_writel(st, st->registers->trigger_register,
			AT91_ADC_TRGR_MOD_PERIOD_TRIG |
			AT91_ADC_TRGR_TRGPER_(st->ts_sample_period_val));
	} else if (status & AT91_ADC_IER_NOPEN) {
		at91_adc_writel(st, st->registers->trigger_register, 0);
		at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_NOPEN |
			ts_data_irq_mask);
		at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);

		input_report_key(st->ts_input, BTN_TOUCH, 0);
		input_sync(st->ts_input);
	} else if ((status & ts_data_irq_mask) == ts_data_irq_mask) {
		/* Now all touchscreen data is ready */

		if (status & AT91_ADC_ISR_PENS) {
			/* validate data by pen contact */
			at91_ts_sample(st);
		} else {
			/* triggered by event that is no pen contact, just read
			 * them to clean the interrupt and discard all.
			 */
			at91_adc_readl(st, AT91_ADC_TSXPOSR);
			at91_adc_readl(st, AT91_ADC_TSYPOSR);
			at91_adc_readl(st, AT91_ADC_TSPRESSR);
		}
	}

	return IRQ_HANDLED;
}

static int at91_adc_channel_init(struct iio_dev *idev)
{
	struct at91_adc_state *st = iio_priv(idev);
	struct iio_chan_spec *chan_array, *timestamp;
	int bit, idx = 0;
	unsigned long rsvd_mask = 0;

	/* If touchscreen is enable, then reserve the adc channels */
	if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
		rsvd_mask = CHAN_MASK_TOUCHSCREEN_4WIRE;
	else if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_5WIRE)
		rsvd_mask = CHAN_MASK_TOUCHSCREEN_5WIRE;

	/* set up the channel mask to reserve touchscreen channels */
	st->channels_mask &= ~rsvd_mask;

	idev->num_channels = bitmap_weight(&st->channels_mask,
					   st->num_channels) + 1;

	chan_array = devm_kzalloc(&idev->dev,
				  ((idev->num_channels + 1) *
					sizeof(struct iio_chan_spec)),
				  GFP_KERNEL);

	if (!chan_array)
		return -ENOMEM;

	for_each_set_bit(bit, &st->channels_mask, st->num_channels) {
		struct iio_chan_spec *chan = chan_array + idx;

		chan->type = IIO_VOLTAGE;
		chan->indexed = 1;
		chan->channel = bit;
		chan->scan_index = idx;
		chan->scan_type.sign = 'u';
		chan->scan_type.realbits = st->res;
		chan->scan_type.storagebits = 16;
		chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
		chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
		idx++;
	}
	timestamp = chan_array + idx;

	timestamp->type = IIO_TIMESTAMP;
	timestamp->channel = -1;
	timestamp->scan_index = idx;
	timestamp->scan_type.sign = 's';
	timestamp->scan_type.realbits = 64;
	timestamp->scan_type.storagebits = 64;

	idev->channels = chan_array;
	return idev->num_channels;
}

static u8 at91_adc_get_trigger_value_by_name(struct iio_dev *idev,
					     struct at91_adc_trigger *triggers,
					     const char *trigger_name)
{
	struct at91_adc_state *st = iio_priv(idev);
	u8 value = 0;
	int i;

	for (i = 0; i < st->trigger_number; i++) {
		char *name = kasprintf(GFP_KERNEL,
				"%s-dev%d-%s",
				idev->name,
				idev->id,
				triggers[i].name);
		if (!name)
			return -ENOMEM;

		if (strcmp(trigger_name, name) == 0) {
			value = triggers[i].value;
			kfree(name);
			break;
		}

		kfree(name);
	}

	return value;
}

static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
{
	struct iio_dev *idev = iio_trigger_get_drvdata(trig);
	struct at91_adc_state *st = iio_priv(idev);
	struct iio_buffer *buffer = idev->buffer;
	struct at91_adc_reg_desc *reg = st->registers;
	u32 status = at91_adc_readl(st, reg->trigger_register);
	u8 value;
	u8 bit;

	value = at91_adc_get_trigger_value_by_name(idev,
						   st->trigger_list,
						   idev->trig->name);
	if (value == 0)
		return -EINVAL;

	if (state) {
		st->buffer = kmalloc(idev->scan_bytes, GFP_KERNEL);
		if (st->buffer == NULL)
			return -ENOMEM;

		at91_adc_writel(st, reg->trigger_register,
				status | value);

		for_each_set_bit(bit, buffer->scan_mask,
				 st->num_channels) {
			struct iio_chan_spec const *chan = idev->channels + bit;
			at91_adc_writel(st, AT91_ADC_CHER,
					AT91_ADC_CH(chan->channel));
		}

		at91_adc_writel(st, AT91_ADC_IER, reg->drdy_mask);

	} else {
		at91_adc_writel(st, AT91_ADC_IDR, reg->drdy_mask);

		at91_adc_writel(st, reg->trigger_register,
				status & ~value);

		for_each_set_bit(bit, buffer->scan_mask,
				 st->num_channels) {
			struct iio_chan_spec const *chan = idev->channels + bit;
			at91_adc_writel(st, AT91_ADC_CHDR,
					AT91_ADC_CH(chan->channel));
		}
		kfree(st->buffer);
	}

	return 0;
}

static const struct iio_trigger_ops at91_adc_trigger_ops = {
	.owner = THIS_MODULE,
	.set_trigger_state = &at91_adc_configure_trigger,
};

static struct iio_trigger *at91_adc_allocate_trigger(struct iio_dev *idev,
						     struct at91_adc_trigger *trigger)
{
	struct iio_trigger *trig;
	int ret;

	trig = iio_trigger_alloc("%s-dev%d-%s", idev->name,
				 idev->id, trigger->name);
	if (trig == NULL)
		return NULL;

	trig->dev.parent = idev->dev.parent;
	iio_trigger_set_drvdata(trig, idev);
	trig->ops = &at91_adc_trigger_ops;

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

	return trig;
}

static int at91_adc_trigger_init(struct iio_dev *idev)
{
	struct at91_adc_state *st = iio_priv(idev);
	int i, ret;

	st->trig = devm_kzalloc(&idev->dev,
				st->trigger_number * sizeof(*st->trig),
				GFP_KERNEL);

	if (st->trig == NULL) {
		ret = -ENOMEM;
		goto error_ret;
	}

	for (i = 0; i < st->trigger_number; i++) {
		if (st->trigger_list[i].is_external && !(st->use_external))
			continue;

		st->trig[i] = at91_adc_allocate_trigger(idev,
							st->trigger_list + i);
		if (st->trig[i] == NULL) {
			dev_err(&idev->dev,
				"Could not allocate trigger %d\n", i);
			ret = -ENOMEM;
			goto error_trigger;
		}
	}

	return 0;

error_trigger:
	for (i--; i >= 0; i--) {
		iio_trigger_unregister(st->trig[i]);
		iio_trigger_free(st->trig[i]);
	}
error_ret:
	return ret;
}

static void at91_adc_trigger_remove(struct iio_dev *idev)
{
	struct at91_adc_state *st = iio_priv(idev);
	int i;

	for (i = 0; i < st->trigger_number; i++) {
		iio_trigger_unregister(st->trig[i]);
		iio_trigger_free(st->trig[i]);
	}
}

static int at91_adc_buffer_init(struct iio_dev *idev)
{
	return iio_triggered_buffer_setup(idev, &iio_pollfunc_store_time,
		&at91_adc_trigger_handler, NULL);
}

static void at91_adc_buffer_remove(struct iio_dev *idev)
{
	iio_triggered_buffer_cleanup(idev);
}

static int at91_adc_read_raw(struct iio_dev *idev,
			     struct iio_chan_spec const *chan,
			     int *val, int *val2, long mask)
{
	struct at91_adc_state *st = iio_priv(idev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		mutex_lock(&st->lock);

		at91_adc_writel(st, AT91_ADC_CHER,
				AT91_ADC_CH(chan->channel));
		at91_adc_writel(st, AT91_ADC_IER, st->registers->drdy_mask);
		at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_START);

		ret = wait_event_interruptible_timeout(st->wq_data_avail,
						       st->done,
						       msecs_to_jiffies(1000));
		if (ret == 0)
			ret = -ETIMEDOUT;
		if (ret < 0) {
			mutex_unlock(&st->lock);
			return ret;
		}

		*val = st->last_value;

		at91_adc_writel(st, AT91_ADC_CHDR,
				AT91_ADC_CH(chan->channel));
		at91_adc_writel(st, AT91_ADC_IDR, st->registers->drdy_mask);

		st->last_value = 0;
		st->done = false;
		mutex_unlock(&st->lock);
		return IIO_VAL_INT;

	case IIO_CHAN_INFO_SCALE:
		*val = st->vref_mv;
		*val2 = chan->scan_type.realbits;
		return IIO_VAL_FRACTIONAL_LOG2;
	default:
		break;
	}
	return -EINVAL;
}

static int at91_adc_of_get_resolution(struct at91_adc_state *st,
				      struct platform_device *pdev)
{
	struct iio_dev *idev = iio_priv_to_dev(st);
	struct device_node *np = pdev->dev.of_node;
	int count, i, ret = 0;
	char *res_name, *s;
	u32 *resolutions;

	count = of_property_count_strings(np, "atmel,adc-res-names");
	if (count < 2) {
		dev_err(&idev->dev, "You must specified at least two resolution names for "
				    "adc-res-names property in the DT\n");
		return count;
	}

	resolutions = kmalloc(count * sizeof(*resolutions), GFP_KERNEL);
	if (!resolutions)
		return -ENOMEM;

	if (of_property_read_u32_array(np, "atmel,adc-res", resolutions, count)) {
		dev_err(&idev->dev, "Missing adc-res property in the DT.\n");
		ret = -ENODEV;
		goto ret;
	}

	if (of_property_read_string(np, "atmel,adc-use-res", (const char **)&res_name))
		res_name = "highres";

	for (i = 0; i < count; i++) {
		if (of_property_read_string_index(np, "atmel,adc-res-names", i, (const char **)&s))
			continue;

		if (strcmp(res_name, s))
			continue;

		st->res = resolutions[i];
		if (!strcmp(res_name, "lowres"))
			st->low_res = true;
		else
			st->low_res = false;

		dev_info(&idev->dev, "Resolution used: %u bits\n", st->res);
		goto ret;
	}

	dev_err(&idev->dev, "There is no resolution for %s\n", res_name);

ret:
	kfree(resolutions);
	return ret;
}

static u32 calc_startup_ticks_9260(u8 startup_time, u32 adc_clk_khz)
{
	/*
	 * Number of ticks needed to cover the startup time of the ADC
	 * as defined in the electrical characteristics of the board,
	 * divided by 8. The formula thus is :
	 *   Startup Time = (ticks + 1) * 8 / ADC Clock
	 */
	return round_up((startup_time * adc_clk_khz / 1000) - 1, 8) / 8;
}

static u32 calc_startup_ticks_9x5(u8 startup_time, u32 adc_clk_khz)
{
	/*
	 * For sama5d3x and at91sam9x5, the formula changes to:
	 * Startup Time = <lookup_table_value> / ADC Clock
	 */
	const int startup_lookup[] = {
		0  , 8  , 16 , 24 ,
		64 , 80 , 96 , 112,
		512, 576, 640, 704,
		768, 832, 896, 960
		};
	int i, size = ARRAY_SIZE(startup_lookup);
	unsigned int ticks;

	ticks = startup_time * adc_clk_khz / 1000;
	for (i = 0; i < size; i++)
		if (ticks < startup_lookup[i])
			break;

	ticks = i;
	if (ticks == size)
		/* Reach the end of lookup table */
		ticks = size - 1;

	return ticks;
}

static const struct of_device_id at91_adc_dt_ids[];

static int at91_adc_probe_dt_ts(struct device_node *node,
	struct at91_adc_state *st, struct device *dev)
{
	int ret;
	u32 prop;

	ret = of_property_read_u32(node, "atmel,adc-ts-wires", &prop);
	if (ret) {
		dev_info(dev, "ADC Touch screen is disabled.\n");
		return 0;
	}

	switch (prop) {
	case 4:
	case 5:
		st->touchscreen_type = prop;
		break;
	default:
		dev_err(dev, "Unsupported number of touchscreen wires (%d). Should be 4 or 5.\n", prop);
		return -EINVAL;
	}

	prop = 0;
	of_property_read_u32(node, "atmel,adc-ts-pressure-threshold", &prop);
	st->ts_pressure_threshold = prop;
	if (st->ts_pressure_threshold) {
		return 0;
	} else {
		dev_err(dev, "Invalid pressure threshold for the touchscreen\n");
		return -EINVAL;
	}
}

static int at91_adc_probe_dt(struct at91_adc_state *st,
			     struct platform_device *pdev)
{
	struct iio_dev *idev = iio_priv_to_dev(st);
	struct device_node *node = pdev->dev.of_node;
	struct device_node *trig_node;
	int i = 0, ret;
	u32 prop;

	if (!node)
		return -EINVAL;

	st->caps = (struct at91_adc_caps *)
		of_match_device(at91_adc_dt_ids, &pdev->dev)->data;

	st->use_external = of_property_read_bool(node, "atmel,adc-use-external-triggers");

	if (of_property_read_u32(node, "atmel,adc-channels-used", &prop)) {
		dev_err(&idev->dev, "Missing adc-channels-used property in the DT.\n");
		ret = -EINVAL;
		goto error_ret;
	}
	st->channels_mask = prop;

	st->sleep_mode = of_property_read_bool(node, "atmel,adc-sleep-mode");

	if (of_property_read_u32(node, "atmel,adc-startup-time", &prop)) {
		dev_err(&idev->dev, "Missing adc-startup-time property in the DT.\n");
		ret = -EINVAL;
		goto error_ret;
	}
	st->startup_time = prop;

	prop = 0;
	of_property_read_u32(node, "atmel,adc-sample-hold-time", &prop);
	st->sample_hold_time = prop;

	if (of_property_read_u32(node, "atmel,adc-vref", &prop)) {
		dev_err(&idev->dev, "Missing adc-vref property in the DT.\n");
		ret = -EINVAL;
		goto error_ret;
	}
	st->vref_mv = prop;

	ret = at91_adc_of_get_resolution(st, pdev);
	if (ret)
		goto error_ret;

	st->registers = &st->caps->registers;
	st->num_channels = st->caps->num_channels;
	st->trigger_number = of_get_child_count(node);
	st->trigger_list = devm_kzalloc(&idev->dev, st->trigger_number *
					sizeof(struct at91_adc_trigger),
					GFP_KERNEL);
	if (!st->trigger_list) {
		dev_err(&idev->dev, "Could not allocate trigger list memory.\n");
		ret = -ENOMEM;
		goto error_ret;
	}

	for_each_child_of_node(node, trig_node) {
		struct at91_adc_trigger *trig = st->trigger_list + i;
		const char *name;

		if (of_property_read_string(trig_node, "trigger-name", &name)) {
			dev_err(&idev->dev, "Missing trigger-name property in the DT.\n");
			ret = -EINVAL;
			goto error_ret;
		}
	        trig->name = name;

		if (of_property_read_u32(trig_node, "trigger-value", &prop)) {
			dev_err(&idev->dev, "Missing trigger-value property in the DT.\n");
			ret = -EINVAL;
			goto error_ret;
		}
	        trig->value = prop;
		trig->is_external = of_property_read_bool(trig_node, "trigger-external");
		i++;
	}

	/* Check if touchscreen is supported. */
	if (st->caps->has_ts)
		return at91_adc_probe_dt_ts(node, st, &idev->dev);
	else
		dev_info(&idev->dev, "not support touchscreen in the adc compatible string.\n");

	return 0;

error_ret:
	return ret;
}

static int at91_adc_probe_pdata(struct at91_adc_state *st,
				struct platform_device *pdev)
{
	struct at91_adc_data *pdata = pdev->dev.platform_data;

	if (!pdata)
		return -EINVAL;

	st->use_external = pdata->use_external_triggers;
	st->vref_mv = pdata->vref;
	st->channels_mask = pdata->channels_used;
	st->num_channels = pdata->num_channels;
	st->startup_time = pdata->startup_time;
	st->trigger_number = pdata->trigger_number;
	st->trigger_list = pdata->trigger_list;
	st->registers = pdata->registers;

	return 0;
}

static const struct iio_info at91_adc_info = {
	.driver_module = THIS_MODULE,
	.read_raw = &at91_adc_read_raw,
};

/* Touchscreen related functions */
static int atmel_ts_open(struct input_dev *dev)
{
	struct at91_adc_state *st = input_get_drvdata(dev);

	at91_adc_writel(st, AT91_ADC_IER, AT91_ADC_IER_PEN);
	return 0;
}

static void atmel_ts_close(struct input_dev *dev)
{
	struct at91_adc_state *st = input_get_drvdata(dev);

	at91_adc_writel(st, AT91_ADC_IDR, AT91_ADC_IER_PEN);
}

static int at91_ts_hw_init(struct at91_adc_state *st, u32 adc_clk_khz)
{
	u32 reg = 0, pendbc;
	int i = 0;

	if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE)
		reg = AT91_ADC_TSMR_TSMODE_4WIRE_PRESS;
	else
		reg = AT91_ADC_TSMR_TSMODE_5WIRE;

	/* a Pen Detect Debounce Time is necessary for the ADC Touch to avoid
	 * pen detect noise.
	 * The formula is : Pen Detect Debounce Time = (2 ^ pendbc) / ADCClock
	 */
	pendbc = round_up(TOUCH_PEN_DETECT_DEBOUNCE_US * adc_clk_khz / 1000, 1);

	while (pendbc >> ++i)
		;	/* Empty! Find the shift offset */
	if (abs(pendbc - (1 << i)) < abs(pendbc - (1 << (i - 1))))
		pendbc = i;
	else
		pendbc = i - 1;

	if (st->caps->has_tsmr) {
		reg |= AT91_ADC_TSMR_TSAV_(st->caps->ts_filter_average)
				& AT91_ADC_TSMR_TSAV;
		reg |= AT91_ADC_TSMR_PENDBC_(pendbc) & AT91_ADC_TSMR_PENDBC;
		reg |= AT91_ADC_TSMR_NOTSDMA;
		reg |= AT91_ADC_TSMR_PENDET_ENA;
		reg |= 0x03 << 8;	/* TSFREQ, need bigger than TSAV */

		at91_adc_writel(st, AT91_ADC_TSMR, reg);
	} else {
		/* TODO: for 9g45 which has no TSMR */
	}

	/* Change adc internal resistor value for better pen detection,
	 * default value is 100 kOhm.
	 * 0 = 200 kOhm, 1 = 150 kOhm, 2 = 100 kOhm, 3 = 50 kOhm
	 * option only available on ES2 and higher
	 */
	at91_adc_writel(st, AT91_ADC_ACR, st->caps->ts_pen_detect_sensitivity
			& AT91_ADC_ACR_PENDETSENS);

	/* Sample Peroid Time = (TRGPER + 1) / ADCClock */
	st->ts_sample_period_val = round_up((TOUCH_SAMPLE_PERIOD_US *
			adc_clk_khz / 1000) - 1, 1);

	return 0;
}

static int at91_ts_register(struct at91_adc_state *st,
		struct platform_device *pdev)
{
	struct input_dev *input;
	struct iio_dev *idev = iio_priv_to_dev(st);
	int ret;

	input = input_allocate_device();
	if (!input) {
		dev_err(&idev->dev, "Failed to allocate TS device!\n");
		return -ENOMEM;
	}

	input->name = DRIVER_NAME;
	input->id.bustype = BUS_HOST;
	input->dev.parent = &pdev->dev;
	input->open = atmel_ts_open;
	input->close = atmel_ts_close;

	__set_bit(EV_ABS, input->evbit);
	__set_bit(EV_KEY, input->evbit);
	__set_bit(BTN_TOUCH, input->keybit);
	input_set_abs_params(input, ABS_X, 0, (1 << MAX_POS_BITS) - 1, 0, 0);
	input_set_abs_params(input, ABS_Y, 0, (1 << MAX_POS_BITS) - 1, 0, 0);
	input_set_abs_params(input, ABS_PRESSURE, 0, 0xffffff, 0, 0);

	st->ts_input = input;
	input_set_drvdata(input, st);

	ret = input_register_device(input);
	if (ret)
		input_free_device(st->ts_input);

	return ret;
}

static void at91_ts_unregister(struct at91_adc_state *st)
{
	input_unregister_device(st->ts_input);
}

static int at91_adc_probe(struct platform_device *pdev)
{
	unsigned int prsc, mstrclk, ticks, adc_clk, adc_clk_khz, shtim;
	int ret;
	struct iio_dev *idev;
	struct at91_adc_state *st;
	struct resource *res;
	u32 reg;

	idev = devm_iio_device_alloc(&pdev->dev, sizeof(struct at91_adc_state));
	if (!idev)
		return -ENOMEM;

	st = iio_priv(idev);

	if (pdev->dev.of_node)
		ret = at91_adc_probe_dt(st, pdev);
	else
		ret = at91_adc_probe_pdata(st, pdev);

	if (ret) {
		dev_err(&pdev->dev, "No platform data available.\n");
		return -EINVAL;
	}

	platform_set_drvdata(pdev, idev);

	idev->dev.parent = &pdev->dev;
	idev->name = dev_name(&pdev->dev);
	idev->modes = INDIO_DIRECT_MODE;
	idev->info = &at91_adc_info;

	st->irq = platform_get_irq(pdev, 0);
	if (st->irq < 0) {
		dev_err(&pdev->dev, "No IRQ ID is designated\n");
		return -ENODEV;
	}

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	st->reg_base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(st->reg_base)) {
		return PTR_ERR(st->reg_base);
	}

	/*
	 * Disable all IRQs before setting up the handler
	 */
	at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_SWRST);
	at91_adc_writel(st, AT91_ADC_IDR, 0xFFFFFFFF);
	ret = request_irq(st->irq,
			  at91_adc_interrupt,
			  0,
			  pdev->dev.driver->name,
			  idev);
	if (ret) {
		dev_err(&pdev->dev, "Failed to allocate IRQ.\n");
		return ret;
	}

	st->clk = devm_clk_get(&pdev->dev, "adc_clk");
	if (IS_ERR(st->clk)) {
		dev_err(&pdev->dev, "Failed to get the clock.\n");
		ret = PTR_ERR(st->clk);
		goto error_free_irq;
	}

	ret = clk_prepare_enable(st->clk);
	if (ret) {
		dev_err(&pdev->dev,
			"Could not prepare or enable the clock.\n");
		goto error_free_irq;
	}

	st->adc_clk = devm_clk_get(&pdev->dev, "adc_op_clk");
	if (IS_ERR(st->adc_clk)) {
		dev_err(&pdev->dev, "Failed to get the ADC clock.\n");
		ret = PTR_ERR(st->adc_clk);
		goto error_disable_clk;
	}

	ret = clk_prepare_enable(st->adc_clk);
	if (ret) {
		dev_err(&pdev->dev,
			"Could not prepare or enable the ADC clock.\n");
		goto error_disable_clk;
	}

	/*
	 * Prescaler rate computation using the formula from the Atmel's
	 * datasheet : ADC Clock = MCK / ((Prescaler + 1) * 2), ADC Clock being
	 * specified by the electrical characteristics of the board.
	 */
	mstrclk = clk_get_rate(st->clk);
	adc_clk = clk_get_rate(st->adc_clk);
	adc_clk_khz = adc_clk / 1000;

	dev_dbg(&pdev->dev, "Master clock is set as: %d Hz, adc_clk should set as: %d Hz\n",
		mstrclk, adc_clk);

	prsc = (mstrclk / (2 * adc_clk)) - 1;

	if (!st->startup_time) {
		dev_err(&pdev->dev, "No startup time available.\n");
		ret = -EINVAL;
		goto error_disable_adc_clk;
	}
	ticks = (*st->caps->calc_startup_ticks)(st->startup_time, adc_clk_khz);

	/*
	 * a minimal Sample and Hold Time is necessary for the ADC to guarantee
	 * the best converted final value between two channels selection
	 * The formula thus is : Sample and Hold Time = (shtim + 1) / ADCClock
	 */
	shtim = round_up((st->sample_hold_time * adc_clk_khz /
			  1000) - 1, 1);

	reg = AT91_ADC_PRESCAL_(prsc) & st->registers->mr_prescal_mask;
	reg |= AT91_ADC_STARTUP_(ticks) & st->registers->mr_startup_mask;
	if (st->low_res)
		reg |= AT91_ADC_LOWRES;
	if (st->sleep_mode)
		reg |= AT91_ADC_SLEEP;
	reg |= AT91_ADC_SHTIM_(shtim) & AT91_ADC_SHTIM;
	at91_adc_writel(st, AT91_ADC_MR, reg);

	/* Setup the ADC channels available on the board */
	ret = at91_adc_channel_init(idev);
	if (ret < 0) {
		dev_err(&pdev->dev, "Couldn't initialize the channels.\n");
		goto error_disable_adc_clk;
	}

	init_waitqueue_head(&st->wq_data_avail);
	mutex_init(&st->lock);

	/*
	 * Since touch screen will set trigger register as period trigger. So
	 * when touch screen is enabled, then we have to disable hardware
	 * trigger for classic adc.
	 */
	if (!st->touchscreen_type) {
		ret = at91_adc_buffer_init(idev);
		if (ret < 0) {
			dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
			goto error_disable_adc_clk;
		}

		ret = at91_adc_trigger_init(idev);
		if (ret < 0) {
			dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
			at91_adc_buffer_remove(idev);
			goto error_disable_adc_clk;
		}
	} else {
		if (!st->caps->has_tsmr) {
			dev_err(&pdev->dev, "We don't support non-TSMR adc\n");
			goto error_disable_adc_clk;
		}

		ret = at91_ts_register(st, pdev);
		if (ret)
			goto error_disable_adc_clk;

		at91_ts_hw_init(st, adc_clk_khz);
	}

	ret = iio_device_register(idev);
	if (ret < 0) {
		dev_err(&pdev->dev, "Couldn't register the device.\n");
		goto error_iio_device_register;
	}

	return 0;

error_iio_device_register:
	if (!st->touchscreen_type) {
		at91_adc_trigger_remove(idev);
		at91_adc_buffer_remove(idev);
	} else {
		at91_ts_unregister(st);
	}
error_disable_adc_clk:
	clk_disable_unprepare(st->adc_clk);
error_disable_clk:
	clk_disable_unprepare(st->clk);
error_free_irq:
	free_irq(st->irq, idev);
	return ret;
}

static int at91_adc_remove(struct platform_device *pdev)
{
	struct iio_dev *idev = platform_get_drvdata(pdev);
	struct at91_adc_state *st = iio_priv(idev);

	iio_device_unregister(idev);
	if (!st->touchscreen_type) {
		at91_adc_trigger_remove(idev);
		at91_adc_buffer_remove(idev);
	} else {
		at91_ts_unregister(st);
	}
	clk_disable_unprepare(st->adc_clk);
	clk_disable_unprepare(st->clk);
	free_irq(st->irq, idev);

	return 0;
}

#ifdef CONFIG_OF
static struct at91_adc_caps at91sam9260_caps = {
	.calc_startup_ticks = calc_startup_ticks_9260,
	.num_channels = 4,
	.registers = {
		.channel_base = AT91_ADC_CHR(0),
		.drdy_mask = AT91_ADC_DRDY,
		.status_register = AT91_ADC_SR,
		.trigger_register = AT91_ADC_TRGR_9260,
		.mr_prescal_mask = AT91_ADC_PRESCAL_9260,
		.mr_startup_mask = AT91_ADC_STARTUP_9260,
	},
};

static struct at91_adc_caps at91sam9g45_caps = {
	.has_ts = true,
	.calc_startup_ticks = calc_startup_ticks_9260,	/* same as 9260 */
	.num_channels = 8,
	.registers = {
		.channel_base = AT91_ADC_CHR(0),
		.drdy_mask = AT91_ADC_DRDY,
		.status_register = AT91_ADC_SR,
		.trigger_register = AT91_ADC_TRGR_9G45,
		.mr_prescal_mask = AT91_ADC_PRESCAL_9G45,
		.mr_startup_mask = AT91_ADC_STARTUP_9G45,
	},
};

static struct at91_adc_caps at91sam9x5_caps = {
	.has_ts = true,
	.has_tsmr = true,
	.ts_filter_average = 3,
	.ts_pen_detect_sensitivity = 2,
	.calc_startup_ticks = calc_startup_ticks_9x5,
	.num_channels = 12,
	.registers = {
		.channel_base = AT91_ADC_CDR0_9X5,
		.drdy_mask = AT91_ADC_SR_DRDY_9X5,
		.status_register = AT91_ADC_SR_9X5,
		.trigger_register = AT91_ADC_TRGR_9X5,
		/* prescal mask is same as 9G45 */
		.mr_prescal_mask = AT91_ADC_PRESCAL_9G45,
		.mr_startup_mask = AT91_ADC_STARTUP_9X5,
	},
};

static const struct of_device_id at91_adc_dt_ids[] = {
	{ .compatible = "atmel,at91sam9260-adc", .data = &at91sam9260_caps },
	{ .compatible = "atmel,at91sam9g45-adc", .data = &at91sam9g45_caps },
	{ .compatible = "atmel,at91sam9x5-adc", .data = &at91sam9x5_caps },
	{},
};
MODULE_DEVICE_TABLE(of, at91_adc_dt_ids);
#endif

static struct platform_driver at91_adc_driver = {
	.probe = at91_adc_probe,
	.remove = at91_adc_remove,
	.driver = {
		   .name = DRIVER_NAME,
		   .of_match_table = of_match_ptr(at91_adc_dt_ids),
	},
};

module_platform_driver(at91_adc_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Atmel AT91 ADC Driver");
MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
OpenPOWER on IntegriCloud