summaryrefslogtreecommitdiffstats
path: root/drivers/input/touchscreen/mxs-lradc-ts.c
blob: 593b8d3e90b5fd2443b8284a6d4cd04b144bdf83 (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
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Freescale MXS LRADC touchscreen driver
 *
 * Copyright (c) 2012 DENX Software Engineering, GmbH.
 * Copyright (c) 2017 Ksenija Stanojevic <ksenija.stanojevic@gmail.com>
 *
 * Authors:
 *  Marek Vasut <marex@denx.de>
 *  Ksenija Stanojevic <ksenija.stanojevic@gmail.com>
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/mfd/core.h>
#include <linux/mfd/mxs-lradc.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>

static const char * const mxs_lradc_ts_irq_names[] = {
	"mxs-lradc-touchscreen",
	"mxs-lradc-channel6",
	"mxs-lradc-channel7",
};

/*
 * Touchscreen handling
 */
enum mxs_lradc_ts_plate {
	LRADC_TOUCH = 0,
	LRADC_SAMPLE_X,
	LRADC_SAMPLE_Y,
	LRADC_SAMPLE_PRESSURE,
	LRADC_SAMPLE_VALID,
};

struct mxs_lradc_ts {
	struct mxs_lradc	*lradc;
	struct device		*dev;

	void __iomem		*base;
	/*
	 * When the touchscreen is enabled, we give it two private virtual
	 * channels: #6 and #7. This means that only 6 virtual channels (instead
	 * of 8) will be available for buffered capture.
	 */
#define TOUCHSCREEN_VCHANNEL1		7
#define TOUCHSCREEN_VCHANNEL2		6

	struct input_dev	*ts_input;

	enum mxs_lradc_ts_plate	cur_plate; /* state machine */
	bool			ts_valid;
	unsigned int		ts_x_pos;
	unsigned int		ts_y_pos;
	unsigned int		ts_pressure;

	/* handle touchscreen's physical behaviour */
	/* samples per coordinate */
	unsigned int		over_sample_cnt;
	/* time clocks between samples */
	unsigned int		over_sample_delay;
	/* time in clocks to wait after the plates where switched */
	unsigned int		settling_delay;
	spinlock_t		lock;
};

struct state_info {
	u32		mask;
	u32		bit;
	u32		x_plate;
	u32		y_plate;
	u32		pressure;
};

static struct state_info info[] = {
	{LRADC_CTRL0_MX23_PLATE_MASK, LRADC_CTRL0_MX23_TOUCH_DETECT_ENABLE,
	 LRADC_CTRL0_MX23_XP | LRADC_CTRL0_MX23_XM,
	 LRADC_CTRL0_MX23_YP | LRADC_CTRL0_MX23_YM,
	 LRADC_CTRL0_MX23_YP | LRADC_CTRL0_MX23_XM},
	{LRADC_CTRL0_MX28_PLATE_MASK, LRADC_CTRL0_MX28_TOUCH_DETECT_ENABLE,
	 LRADC_CTRL0_MX28_XPPSW | LRADC_CTRL0_MX28_XNNSW,
	 LRADC_CTRL0_MX28_YPPSW | LRADC_CTRL0_MX28_YNNSW,
	 LRADC_CTRL0_MX28_YPPSW | LRADC_CTRL0_MX28_XNNSW}
};

static bool mxs_lradc_check_touch_event(struct mxs_lradc_ts *ts)
{
	return !!(readl(ts->base + LRADC_STATUS) &
					LRADC_STATUS_TOUCH_DETECT_RAW);
}

static void mxs_lradc_map_ts_channel(struct mxs_lradc_ts *ts, unsigned int vch,
				     unsigned int ch)
{
	writel(LRADC_CTRL4_LRADCSELECT_MASK(vch),
	       ts->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
	writel(LRADC_CTRL4_LRADCSELECT(vch, ch),
	       ts->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
}

static void mxs_lradc_setup_ts_channel(struct mxs_lradc_ts *ts, unsigned int ch)
{
	/*
	 * prepare for oversampling conversion
	 *
	 * from the datasheet:
	 * "The ACCUMULATE bit in the appropriate channel register
	 * HW_LRADC_CHn must be set to 1 if NUM_SAMPLES is greater then 0;
	 * otherwise, the IRQs will not fire."
	 */
	writel(LRADC_CH_ACCUMULATE |
	       LRADC_CH_NUM_SAMPLES(ts->over_sample_cnt - 1),
	       ts->base + LRADC_CH(ch));

	/* from the datasheet:
	 * "Software must clear this register in preparation for a
	 * multi-cycle accumulation.
	 */
	writel(LRADC_CH_VALUE_MASK,
	       ts->base + LRADC_CH(ch) + STMP_OFFSET_REG_CLR);

	/*
	 * prepare the delay/loop unit according to the oversampling count
	 *
	 * from the datasheet:
	 * "The DELAY fields in HW_LRADC_DELAY0, HW_LRADC_DELAY1,
	 * HW_LRADC_DELAY2, and HW_LRADC_DELAY3 must be non-zero; otherwise,
	 * the LRADC will not trigger the delay group."
	 */
	writel(LRADC_DELAY_TRIGGER(1 << ch) | LRADC_DELAY_TRIGGER_DELAYS(0) |
	       LRADC_DELAY_LOOP(ts->over_sample_cnt - 1) |
	       LRADC_DELAY_DELAY(ts->over_sample_delay - 1),
	       ts->base + LRADC_DELAY(3));

	writel(LRADC_CTRL1_LRADC_IRQ(ch),
	       ts->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);

	/*
	 * after changing the touchscreen plates setting
	 * the signals need some initial time to settle. Start the
	 * SoC's delay unit and start the conversion later
	 * and automatically.
	 */
	writel(LRADC_DELAY_TRIGGER(0) | LRADC_DELAY_TRIGGER_DELAYS(BIT(3)) |
	       LRADC_DELAY_KICK | LRADC_DELAY_DELAY(ts->settling_delay),
	       ts->base + LRADC_DELAY(2));
}

/*
 * Pressure detection is special:
 * We want to do both required measurements for the pressure detection in
 * one turn. Use the hardware features to chain both conversions and let the
 * hardware report one interrupt if both conversions are done
 */
static void mxs_lradc_setup_ts_pressure(struct mxs_lradc_ts *ts,
					unsigned int ch1, unsigned int ch2)
{
	u32 reg;

	/*
	 * prepare for oversampling conversion
	 *
	 * from the datasheet:
	 * "The ACCUMULATE bit in the appropriate channel register
	 * HW_LRADC_CHn must be set to 1 if NUM_SAMPLES is greater then 0;
	 * otherwise, the IRQs will not fire."
	 */
	reg = LRADC_CH_ACCUMULATE |
		LRADC_CH_NUM_SAMPLES(ts->over_sample_cnt - 1);
	writel(reg, ts->base + LRADC_CH(ch1));
	writel(reg, ts->base + LRADC_CH(ch2));

	/* from the datasheet:
	 * "Software must clear this register in preparation for a
	 * multi-cycle accumulation.
	 */
	writel(LRADC_CH_VALUE_MASK,
	       ts->base + LRADC_CH(ch1) + STMP_OFFSET_REG_CLR);
	writel(LRADC_CH_VALUE_MASK,
	       ts->base + LRADC_CH(ch2) + STMP_OFFSET_REG_CLR);

	/* prepare the delay/loop unit according to the oversampling count */
	writel(LRADC_DELAY_TRIGGER(1 << ch1) | LRADC_DELAY_TRIGGER(1 << ch2) |
	       LRADC_DELAY_TRIGGER_DELAYS(0) |
	       LRADC_DELAY_LOOP(ts->over_sample_cnt - 1) |
	       LRADC_DELAY_DELAY(ts->over_sample_delay - 1),
	       ts->base + LRADC_DELAY(3));

	writel(LRADC_CTRL1_LRADC_IRQ(ch2),
	       ts->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);

	/*
	 * after changing the touchscreen plates setting
	 * the signals need some initial time to settle. Start the
	 * SoC's delay unit and start the conversion later
	 * and automatically.
	 */
	writel(LRADC_DELAY_TRIGGER(0) | LRADC_DELAY_TRIGGER_DELAYS(BIT(3)) |
	       LRADC_DELAY_KICK | LRADC_DELAY_DELAY(ts->settling_delay),
	       ts->base + LRADC_DELAY(2));
}

static unsigned int mxs_lradc_ts_read_raw_channel(struct mxs_lradc_ts *ts,
						  unsigned int channel)
{
	u32 reg;
	unsigned int num_samples, val;

	reg = readl(ts->base + LRADC_CH(channel));
	if (reg & LRADC_CH_ACCUMULATE)
		num_samples = ts->over_sample_cnt;
	else
		num_samples = 1;

	val = (reg & LRADC_CH_VALUE_MASK) >> LRADC_CH_VALUE_OFFSET;
	return val / num_samples;
}

static unsigned int mxs_lradc_read_ts_pressure(struct mxs_lradc_ts *ts,
					unsigned int ch1, unsigned int ch2)
{
	u32 reg, mask;
	unsigned int pressure, m1, m2;

	mask = LRADC_CTRL1_LRADC_IRQ(ch1) | LRADC_CTRL1_LRADC_IRQ(ch2);
	reg = readl(ts->base + LRADC_CTRL1) & mask;

	while (reg != mask) {
		reg = readl(ts->base + LRADC_CTRL1) & mask;
		dev_dbg(ts->dev, "One channel is still busy: %X\n", reg);
	}

	m1 = mxs_lradc_ts_read_raw_channel(ts, ch1);
	m2 = mxs_lradc_ts_read_raw_channel(ts, ch2);

	if (m2 == 0) {
		dev_warn(ts->dev, "Cannot calculate pressure\n");
		return 1 << (LRADC_RESOLUTION - 1);
	}

	/* simply scale the value from 0 ... max ADC resolution */
	pressure = m1;
	pressure *= (1 << LRADC_RESOLUTION);
	pressure /= m2;

	dev_dbg(ts->dev, "Pressure = %u\n", pressure);
	return pressure;
}

#define TS_CH_XP 2
#define TS_CH_YP 3
#define TS_CH_XM 4
#define TS_CH_YM 5

/*
 * YP(open)--+-------------+
 *	     |		   |--+
 *	     |		   |  |
 *    YM(-)--+-------------+  |
 *	       +--------------+
 *	       |	      |
 *	   XP(weak+)	    XM(open)
 *
 * "weak+" means 200k Ohm VDDIO
 * (-) means GND
 */
static void mxs_lradc_setup_touch_detection(struct mxs_lradc_ts *ts)
{
	struct mxs_lradc *lradc = ts->lradc;

	/*
	 * In order to detect a touch event the 'touch detect enable' bit
	 * enables:
	 *  - a weak pullup to the X+ connector
	 *  - a strong ground at the Y- connector
	 */
	writel(info[lradc->soc].mask,
	       ts->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
	writel(info[lradc->soc].bit,
	       ts->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
}

/*
 * YP(meas)--+-------------+
 *	     |		   |--+
 *	     |		   |  |
 * YM(open)--+-------------+  |
 *	       +--------------+
 *	       |	      |
 *	     XP(+)	    XM(-)
 *
 * (+) means here 1.85 V
 * (-) means here GND
 */
static void mxs_lradc_prepare_x_pos(struct mxs_lradc_ts *ts)
{
	struct mxs_lradc *lradc = ts->lradc;

	writel(info[lradc->soc].mask,
	       ts->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
	writel(info[lradc->soc].x_plate,
	       ts->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);

	ts->cur_plate = LRADC_SAMPLE_X;
	mxs_lradc_map_ts_channel(ts, TOUCHSCREEN_VCHANNEL1, TS_CH_YP);
	mxs_lradc_setup_ts_channel(ts, TOUCHSCREEN_VCHANNEL1);
}

/*
 *   YP(+)--+-------------+
 *	    |		  |--+
 *	    |		  |  |
 *   YM(-)--+-------------+  |
 *	      +--------------+
 *	      |		     |
 *	   XP(open)	   XM(meas)
 *
 * (+) means here 1.85 V
 * (-) means here GND
 */
static void mxs_lradc_prepare_y_pos(struct mxs_lradc_ts *ts)
{
	struct mxs_lradc *lradc = ts->lradc;

	writel(info[lradc->soc].mask,
	       ts->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
	writel(info[lradc->soc].y_plate,
	       ts->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);

	ts->cur_plate = LRADC_SAMPLE_Y;
	mxs_lradc_map_ts_channel(ts, TOUCHSCREEN_VCHANNEL1, TS_CH_XM);
	mxs_lradc_setup_ts_channel(ts, TOUCHSCREEN_VCHANNEL1);
}

/*
 *    YP(+)--+-------------+
 *	     |		   |--+
 *	     |		   |  |
 * YM(meas)--+-------------+  |
 *	       +--------------+
 *	       |	      |
 *	    XP(meas)	    XM(-)
 *
 * (+) means here 1.85 V
 * (-) means here GND
 */
static void mxs_lradc_prepare_pressure(struct mxs_lradc_ts *ts)
{
	struct mxs_lradc *lradc = ts->lradc;

	writel(info[lradc->soc].mask,
	       ts->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
	writel(info[lradc->soc].pressure,
	       ts->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);

	ts->cur_plate = LRADC_SAMPLE_PRESSURE;
	mxs_lradc_map_ts_channel(ts, TOUCHSCREEN_VCHANNEL1, TS_CH_YM);
	mxs_lradc_map_ts_channel(ts, TOUCHSCREEN_VCHANNEL2, TS_CH_XP);
	mxs_lradc_setup_ts_pressure(ts, TOUCHSCREEN_VCHANNEL2,
				    TOUCHSCREEN_VCHANNEL1);
}

static void mxs_lradc_enable_touch_detection(struct mxs_lradc_ts *ts)
{
	mxs_lradc_setup_touch_detection(ts);

	ts->cur_plate = LRADC_TOUCH;
	writel(LRADC_CTRL1_TOUCH_DETECT_IRQ | LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
	       ts->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
	writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
	       ts->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
}

static void mxs_lradc_start_touch_event(struct mxs_lradc_ts *ts)
{
	writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
	       ts->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
	writel(LRADC_CTRL1_LRADC_IRQ_EN(TOUCHSCREEN_VCHANNEL1),
	       ts->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
	/*
	 * start with the Y-pos, because it uses nearly the same plate
	 * settings like the touch detection
	 */
	mxs_lradc_prepare_y_pos(ts);
}

static void mxs_lradc_report_ts_event(struct mxs_lradc_ts *ts)
{
	input_report_abs(ts->ts_input, ABS_X, ts->ts_x_pos);
	input_report_abs(ts->ts_input, ABS_Y, ts->ts_y_pos);
	input_report_abs(ts->ts_input, ABS_PRESSURE, ts->ts_pressure);
	input_report_key(ts->ts_input, BTN_TOUCH, 1);
	input_sync(ts->ts_input);
}

static void mxs_lradc_complete_touch_event(struct mxs_lradc_ts *ts)
{
	mxs_lradc_setup_touch_detection(ts);
	ts->cur_plate = LRADC_SAMPLE_VALID;
	/*
	 * start a dummy conversion to burn time to settle the signals
	 * note: we are not interested in the conversion's value
	 */
	writel(0, ts->base + LRADC_CH(TOUCHSCREEN_VCHANNEL1));
	writel(LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL1) |
	       LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL2),
	       ts->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
	writel(LRADC_DELAY_TRIGGER(1 << TOUCHSCREEN_VCHANNEL1) |
	       LRADC_DELAY_KICK | LRADC_DELAY_DELAY(10),
	       ts->base + LRADC_DELAY(2));
}

/*
 * in order to avoid false measurements, report only samples where
 * the surface is still touched after the position measurement
 */
static void mxs_lradc_finish_touch_event(struct mxs_lradc_ts *ts, bool valid)
{
	/* if it is still touched, report the sample */
	if (valid && mxs_lradc_check_touch_event(ts)) {
		ts->ts_valid = true;
		mxs_lradc_report_ts_event(ts);
	}

	/* if it is even still touched, continue with the next measurement */
	if (mxs_lradc_check_touch_event(ts)) {
		mxs_lradc_prepare_y_pos(ts);
		return;
	}

	if (ts->ts_valid) {
		/* signal the release */
		ts->ts_valid = false;
		input_report_key(ts->ts_input, BTN_TOUCH, 0);
		input_sync(ts->ts_input);
	}

	/* if it is released, wait for the next touch via IRQ */
	ts->cur_plate = LRADC_TOUCH;
	writel(0, ts->base + LRADC_DELAY(2));
	writel(0, ts->base + LRADC_DELAY(3));
	writel(LRADC_CTRL1_TOUCH_DETECT_IRQ |
	       LRADC_CTRL1_LRADC_IRQ_EN(TOUCHSCREEN_VCHANNEL1) |
	       LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL1),
	       ts->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
	writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
	       ts->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
}

/* touchscreen's state machine */
static void mxs_lradc_handle_touch(struct mxs_lradc_ts *ts)
{
	switch (ts->cur_plate) {
	case LRADC_TOUCH:
		if (mxs_lradc_check_touch_event(ts))
			mxs_lradc_start_touch_event(ts);
		writel(LRADC_CTRL1_TOUCH_DETECT_IRQ,
		       ts->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
		return;

	case LRADC_SAMPLE_Y:
		ts->ts_y_pos =
		    mxs_lradc_ts_read_raw_channel(ts, TOUCHSCREEN_VCHANNEL1);
		mxs_lradc_prepare_x_pos(ts);
		return;

	case LRADC_SAMPLE_X:
		ts->ts_x_pos =
		    mxs_lradc_ts_read_raw_channel(ts, TOUCHSCREEN_VCHANNEL1);
		mxs_lradc_prepare_pressure(ts);
		return;

	case LRADC_SAMPLE_PRESSURE:
		ts->ts_pressure =
		    mxs_lradc_read_ts_pressure(ts,
					       TOUCHSCREEN_VCHANNEL2,
					       TOUCHSCREEN_VCHANNEL1);
		mxs_lradc_complete_touch_event(ts);
		return;

	case LRADC_SAMPLE_VALID:
		mxs_lradc_finish_touch_event(ts, 1);
		break;
	}
}

/* IRQ Handling */
static irqreturn_t mxs_lradc_ts_handle_irq(int irq, void *data)
{
	struct mxs_lradc_ts *ts = data;
	struct mxs_lradc *lradc = ts->lradc;
	unsigned long reg = readl(ts->base + LRADC_CTRL1);
	u32 clr_irq = mxs_lradc_irq_mask(lradc);
	const u32 ts_irq_mask =
		LRADC_CTRL1_TOUCH_DETECT_IRQ |
		LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL1) |
		LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL2);
	unsigned long flags;

	if (!(reg & mxs_lradc_irq_mask(lradc)))
		return IRQ_NONE;

	if (reg & ts_irq_mask) {
		spin_lock_irqsave(&ts->lock, flags);
		mxs_lradc_handle_touch(ts);
		spin_unlock_irqrestore(&ts->lock, flags);
		/* Make sure we don't clear the next conversion's interrupt. */
		clr_irq &= ~(LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL1) |
				LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL2));
		writel(reg & clr_irq,
		       ts->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
	}

	return IRQ_HANDLED;
}

static int mxs_lradc_ts_open(struct input_dev *dev)
{
	struct mxs_lradc_ts *ts = input_get_drvdata(dev);

	/* Enable the touch-detect circuitry. */
	mxs_lradc_enable_touch_detection(ts);

	return 0;
}

static void mxs_lradc_ts_stop(struct mxs_lradc_ts *ts)
{
	int i;
	struct mxs_lradc *lradc = ts->lradc;

	/* stop all interrupts from firing */
	writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN |
	       LRADC_CTRL1_LRADC_IRQ_EN(TOUCHSCREEN_VCHANNEL1) |
	       LRADC_CTRL1_LRADC_IRQ_EN(TOUCHSCREEN_VCHANNEL2),
	       ts->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);

	/* Power-down touchscreen touch-detect circuitry. */
	writel(info[lradc->soc].mask,
	       ts->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);

	writel(lradc->buffer_vchans << LRADC_CTRL1_LRADC_IRQ_EN_OFFSET,
	       ts->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);

	for (i = 1; i < LRADC_MAX_DELAY_CHANS; i++)
		writel(0, ts->base + LRADC_DELAY(i));
}

static void mxs_lradc_ts_close(struct input_dev *dev)
{
	struct mxs_lradc_ts *ts = input_get_drvdata(dev);

	mxs_lradc_ts_stop(ts);
}

static void mxs_lradc_ts_hw_init(struct mxs_lradc_ts *ts)
{
	struct mxs_lradc *lradc = ts->lradc;

	/* Configure the touchscreen type */
	if (lradc->soc == IMX28_LRADC) {
		writel(LRADC_CTRL0_MX28_TOUCH_SCREEN_TYPE,
		       ts->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);

		if (lradc->touchscreen_wire == MXS_LRADC_TOUCHSCREEN_5WIRE)
			writel(LRADC_CTRL0_MX28_TOUCH_SCREEN_TYPE,
			       ts->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
	}
}

static int mxs_lradc_ts_register(struct mxs_lradc_ts *ts)
{
	struct input_dev *input;
	struct device *dev = ts->dev;

	input = devm_input_allocate_device(dev);
	if (!input)
		return -ENOMEM;

	input->name = "mxs-lradc-ts";
	input->id.bustype = BUS_HOST;
	input->open = mxs_lradc_ts_open;
	input->close = mxs_lradc_ts_close;

	__set_bit(INPUT_PROP_DIRECT, input->propbit);
	input_set_capability(input, EV_KEY, BTN_TOUCH);
	input_set_abs_params(input, ABS_X, 0, LRADC_SINGLE_SAMPLE_MASK, 0, 0);
	input_set_abs_params(input, ABS_Y, 0, LRADC_SINGLE_SAMPLE_MASK, 0, 0);
	input_set_abs_params(input, ABS_PRESSURE, 0, LRADC_SINGLE_SAMPLE_MASK,
			     0, 0);

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

	return input_register_device(input);
}

static int mxs_lradc_ts_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct device_node *node = dev->parent->of_node;
	struct mxs_lradc *lradc = dev_get_drvdata(dev->parent);
	struct mxs_lradc_ts *ts;
	struct resource *iores;
	int ret, irq, virq, i;
	u32 ts_wires = 0, adapt;

	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
	if (!ts)
		return -ENOMEM;

	platform_set_drvdata(pdev, ts);

	ts->lradc = lradc;
	ts->dev = dev;
	spin_lock_init(&ts->lock);

	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!iores)
		return -EINVAL;
	ts->base = devm_ioremap(dev, iores->start, resource_size(iores));
	if (!ts->base)
		return -ENOMEM;

	ret = of_property_read_u32(node, "fsl,lradc-touchscreen-wires",
				   &ts_wires);
	if (ret)
		return ret;

	if (of_property_read_u32(node, "fsl,ave-ctrl", &adapt)) {
		ts->over_sample_cnt = 4;
	} else {
		if (adapt >= 1 && adapt <= 32) {
			ts->over_sample_cnt = adapt;
		} else {
			dev_err(ts->dev, "Invalid sample count (%u)\n",
				adapt);
			return -EINVAL;
		}
	}

	if (of_property_read_u32(node, "fsl,ave-delay", &adapt)) {
		ts->over_sample_delay = 2;
	} else {
		if (adapt >= 2 && adapt <= LRADC_DELAY_DELAY_MASK + 1) {
			ts->over_sample_delay = adapt;
		} else {
			dev_err(ts->dev, "Invalid sample delay (%u)\n",
				adapt);
			return -EINVAL;
		}
	}

	if (of_property_read_u32(node, "fsl,settling", &adapt)) {
		ts->settling_delay = 10;
	} else {
		if (adapt >= 1 && adapt <= LRADC_DELAY_DELAY_MASK) {
			ts->settling_delay = adapt;
		} else {
			dev_err(ts->dev, "Invalid settling delay (%u)\n",
				adapt);
			return -EINVAL;
		}
	}

	ret = stmp_reset_block(ts->base);
	if (ret)
		return ret;

	mxs_lradc_ts_hw_init(ts);

	for (i = 0; i < 3; i++) {
		irq = platform_get_irq_byname(pdev, mxs_lradc_ts_irq_names[i]);
		if (irq < 0)
			return irq;

		virq = irq_of_parse_and_map(node, irq);

		mxs_lradc_ts_stop(ts);

		ret = devm_request_irq(dev, virq,
				       mxs_lradc_ts_handle_irq,
				       0, mxs_lradc_ts_irq_names[i], ts);
		if (ret)
			return ret;
	}

	return mxs_lradc_ts_register(ts);
}

static struct platform_driver mxs_lradc_ts_driver = {
	.driver	= {
		.name = "mxs-lradc-ts",
	},
	.probe	= mxs_lradc_ts_probe,
};
module_platform_driver(mxs_lradc_ts_driver);

MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
MODULE_DESCRIPTION("Freescale MXS LRADC touchscreen driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:mxs-lradc-ts");