summaryrefslogtreecommitdiff
path: root/drivers/input/touchscreen/tsc200x-core.c
blob: e0fde590df8e5f4a7c749ee2b40e5e0b8750edff (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
/*
 * TSC2004/TSC2005 touchscreen driver core
 *
 * Copyright (C) 2006-2010 Nokia Corporation
 * Copyright (C) 2015 QWERTY Embedded Design
 * Copyright (C) 2015 EMAC Inc.
 *
 * Author: Lauri Leukkunen <lauri.leukkunen@nokia.com>
 * based on TSC2301 driver by Klaus K. Pedersen <klaus.k.pedersen@nokia.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/input.h>
#include <linux/input/touchscreen.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/pm.h>
#include <linux/of.h>
#include <linux/regulator/consumer.h>
#include <linux/regmap.h>
#include <linux/gpio/consumer.h>
#include "tsc200x-core.h"

/*
 * The touchscreen interface operates as follows:
 *
 * 1) Pen is pressed against the touchscreen.
 * 2) TSC200X performs AD conversion.
 * 3) After the conversion is done TSC200X drives DAV line down.
 * 4) GPIO IRQ is received and tsc200x_irq_thread() is scheduled.
 * 5) tsc200x_irq_thread() queues up a transfer to fetch the x, y, z1, z2
 *    values.
 * 6) tsc200x_irq_thread() reports coordinates to input layer and sets up
 *    tsc200x_penup_timer() to be called after TSC200X_PENUP_TIME_MS (40ms).
 * 7) When the penup timer expires, there have not been touch or DAV interrupts
 *    during the last 40ms which means the pen has been lifted.
 *
 * ESD recovery via a hardware reset is done if the TSC200X doesn't respond
 * after a configurable period (in ms) of activity. If esd_timeout is 0, the
 * watchdog is disabled.
 */

static const struct regmap_range tsc200x_writable_ranges[] = {
	regmap_reg_range(TSC200X_REG_AUX_HIGH, TSC200X_REG_CFR2),
};

static const struct regmap_access_table tsc200x_writable_table = {
	.yes_ranges = tsc200x_writable_ranges,
	.n_yes_ranges = ARRAY_SIZE(tsc200x_writable_ranges),
};

const struct regmap_config tsc200x_regmap_config = {
	.reg_bits = 8,
	.val_bits = 16,
	.reg_stride = 0x08,
	.max_register = 0x78,
	.read_flag_mask = TSC200X_REG_READ,
	.write_flag_mask = TSC200X_REG_PND0,
	.wr_table = &tsc200x_writable_table,
	.use_single_rw = true,
};
EXPORT_SYMBOL_GPL(tsc200x_regmap_config);

struct tsc200x_data {
	u16 x;
	u16 y;
	u16 z1;
	u16 z2;
} __packed;
#define TSC200X_DATA_REGS 4

struct tsc200x {
	struct device           *dev;
	struct regmap		*regmap;
	__u16                   bustype;

	struct input_dev	*idev;
	char			phys[32];

	struct mutex		mutex;

	/* raw copy of previous x,y,z */
	int			in_x;
	int			in_y;
	int                     in_z1;
	int			in_z2;

	spinlock_t		lock;
	struct timer_list	penup_timer;

	unsigned int		esd_timeout;
	struct delayed_work	esd_work;
	unsigned long		last_valid_interrupt;

	unsigned int		x_plate_ohm;

	bool			opened;
	bool			suspended;

	bool			pen_down;

	struct regulator	*vio;

	struct gpio_desc	*reset_gpio;
	int			(*tsc200x_cmd)(struct device *dev, u8 cmd);
	int			irq;
};

static void tsc200x_update_pen_state(struct tsc200x *ts,
				     int x, int y, int pressure)
{
	if (pressure) {
		input_report_abs(ts->idev, ABS_X, x);
		input_report_abs(ts->idev, ABS_Y, y);
		input_report_abs(ts->idev, ABS_PRESSURE, pressure);
		if (!ts->pen_down) {
			input_report_key(ts->idev, BTN_TOUCH, !!pressure);
			ts->pen_down = true;
		}
	} else {
		input_report_abs(ts->idev, ABS_PRESSURE, 0);
		if (ts->pen_down) {
			input_report_key(ts->idev, BTN_TOUCH, 0);
			ts->pen_down = false;
		}
	}
	input_sync(ts->idev);
	dev_dbg(ts->dev, "point(%4d,%4d), pressure (%4d)\n", x, y,
		pressure);
}

static irqreturn_t tsc200x_irq_thread(int irq, void *_ts)
{
	struct tsc200x *ts = _ts;
	unsigned long flags;
	unsigned int pressure;
	struct tsc200x_data tsdata;
	int error;

	/* read the coordinates */
	error = regmap_bulk_read(ts->regmap, TSC200X_REG_X, &tsdata,
				 TSC200X_DATA_REGS);
	if (unlikely(error))
		goto out;

	/* validate position */
	if (unlikely(tsdata.x > MAX_12BIT || tsdata.y > MAX_12BIT))
		goto out;

	/* Skip reading if the pressure components are out of range */
	if (unlikely(tsdata.z1 == 0 || tsdata.z2 > MAX_12BIT))
		goto out;
	if (unlikely(tsdata.z1 >= tsdata.z2))
		goto out;

       /*
	* Skip point if this is a pen down with the exact same values as
	* the value before pen-up - that implies SPI fed us stale data
	*/
	if (!ts->pen_down &&
	    ts->in_x == tsdata.x && ts->in_y == tsdata.y &&
	    ts->in_z1 == tsdata.z1 && ts->in_z2 == tsdata.z2) {
		goto out;
	}

	/*
	 * At this point we are happy we have a valid and useful reading.
	 * Remember it for later comparisons. We may now begin downsampling.
	 */
	ts->in_x = tsdata.x;
	ts->in_y = tsdata.y;
	ts->in_z1 = tsdata.z1;
	ts->in_z2 = tsdata.z2;

	/* Compute touch pressure resistance using equation #1 */
	pressure = tsdata.x * (tsdata.z2 - tsdata.z1) / tsdata.z1;
	pressure = pressure * ts->x_plate_ohm / 4096;
	if (unlikely(pressure > MAX_12BIT))
		goto out;

	spin_lock_irqsave(&ts->lock, flags);

	tsc200x_update_pen_state(ts, tsdata.x, tsdata.y, pressure);
	mod_timer(&ts->penup_timer,
		  jiffies + msecs_to_jiffies(TSC200X_PENUP_TIME_MS));

	spin_unlock_irqrestore(&ts->lock, flags);

	ts->last_valid_interrupt = jiffies;
out:
	return IRQ_HANDLED;
}

static void tsc200x_penup_timer(struct timer_list *t)
{
	struct tsc200x *ts = from_timer(ts, t, penup_timer);
	unsigned long flags;

	spin_lock_irqsave(&ts->lock, flags);
	tsc200x_update_pen_state(ts, 0, 0, 0);
	spin_unlock_irqrestore(&ts->lock, flags);
}

static void tsc200x_start_scan(struct tsc200x *ts)
{
	regmap_write(ts->regmap, TSC200X_REG_CFR0, TSC200X_CFR0_INITVALUE);
	regmap_write(ts->regmap, TSC200X_REG_CFR1, TSC200X_CFR1_INITVALUE);
	regmap_write(ts->regmap, TSC200X_REG_CFR2, TSC200X_CFR2_INITVALUE);
	ts->tsc200x_cmd(ts->dev, TSC200X_CMD_NORMAL);
}

static void tsc200x_stop_scan(struct tsc200x *ts)
{
	ts->tsc200x_cmd(ts->dev, TSC200X_CMD_STOP);
}

static void tsc200x_reset(struct tsc200x *ts)
{
	if (ts->reset_gpio) {
		gpiod_set_value_cansleep(ts->reset_gpio, 1);
		usleep_range(100, 500); /* only 10us required */
		gpiod_set_value_cansleep(ts->reset_gpio, 0);
	}
}

/* must be called with ts->mutex held */
static void __tsc200x_disable(struct tsc200x *ts)
{
	tsc200x_stop_scan(ts);

	disable_irq(ts->irq);
	del_timer_sync(&ts->penup_timer);

	cancel_delayed_work_sync(&ts->esd_work);

	enable_irq(ts->irq);
}

/* must be called with ts->mutex held */
static void __tsc200x_enable(struct tsc200x *ts)
{
	tsc200x_start_scan(ts);

	if (ts->esd_timeout && ts->reset_gpio) {
		ts->last_valid_interrupt = jiffies;
		schedule_delayed_work(&ts->esd_work,
				round_jiffies_relative(
					msecs_to_jiffies(ts->esd_timeout)));
	}
}

static ssize_t tsc200x_selftest_show(struct device *dev,
				     struct device_attribute *attr,
				     char *buf)
{
	struct tsc200x *ts = dev_get_drvdata(dev);
	unsigned int temp_high;
	unsigned int temp_high_orig;
	unsigned int temp_high_test;
	bool success = true;
	int error;

	mutex_lock(&ts->mutex);

	/*
	 * Test TSC200X communications via temp high register.
	 */
	__tsc200x_disable(ts);

	error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high_orig);
	if (error) {
		dev_warn(dev, "selftest failed: read error %d\n", error);
		success = false;
		goto out;
	}

	temp_high_test = (temp_high_orig - 1) & MAX_12BIT;

	error = regmap_write(ts->regmap, TSC200X_REG_TEMP_HIGH, temp_high_test);
	if (error) {
		dev_warn(dev, "selftest failed: write error %d\n", error);
		success = false;
		goto out;
	}

	error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high);
	if (error) {
		dev_warn(dev, "selftest failed: read error %d after write\n",
			 error);
		success = false;
		goto out;
	}

	if (temp_high != temp_high_test) {
		dev_warn(dev, "selftest failed: %d != %d\n",
			 temp_high, temp_high_test);
		success = false;
	}

	/* hardware reset */
	tsc200x_reset(ts);

	if (!success)
		goto out;

	/* test that the reset really happened */
	error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high);
	if (error) {
		dev_warn(dev, "selftest failed: read error %d after reset\n",
			 error);
		success = false;
		goto out;
	}

	if (temp_high != temp_high_orig) {
		dev_warn(dev, "selftest failed after reset: %d != %d\n",
			 temp_high, temp_high_orig);
		success = false;
	}

out:
	__tsc200x_enable(ts);
	mutex_unlock(&ts->mutex);

	return sprintf(buf, "%d\n", success);
}

static DEVICE_ATTR(selftest, S_IRUGO, tsc200x_selftest_show, NULL);

static struct attribute *tsc200x_attrs[] = {
	&dev_attr_selftest.attr,
	NULL
};

static umode_t tsc200x_attr_is_visible(struct kobject *kobj,
				      struct attribute *attr, int n)
{
	struct device *dev = container_of(kobj, struct device, kobj);
	struct tsc200x *ts = dev_get_drvdata(dev);
	umode_t mode = attr->mode;

	if (attr == &dev_attr_selftest.attr) {
		if (!ts->reset_gpio)
			mode = 0;
	}

	return mode;
}

static const struct attribute_group tsc200x_attr_group = {
	.is_visible	= tsc200x_attr_is_visible,
	.attrs		= tsc200x_attrs,
};

static void tsc200x_esd_work(struct work_struct *work)
{
	struct tsc200x *ts = container_of(work, struct tsc200x, esd_work.work);
	int error;
	unsigned int r;

	if (!mutex_trylock(&ts->mutex)) {
		/*
		 * If the mutex is taken, it means that disable or enable is in
		 * progress. In that case just reschedule the work. If the work
		 * is not needed, it will be canceled by disable.
		 */
		goto reschedule;
	}

	if (time_is_after_jiffies(ts->last_valid_interrupt +
				  msecs_to_jiffies(ts->esd_timeout)))
		goto out;

	/* We should be able to read register without disabling interrupts. */
	error = regmap_read(ts->regmap, TSC200X_REG_CFR0, &r);
	if (!error &&
	    !((r ^ TSC200X_CFR0_INITVALUE) & TSC200X_CFR0_RW_MASK)) {
		goto out;
	}

	/*
	 * If we could not read our known value from configuration register 0
	 * then we should reset the controller as if from power-up and start
	 * scanning again.
	 */
	dev_info(ts->dev, "TSC200X not responding - resetting\n");

	disable_irq(ts->irq);
	del_timer_sync(&ts->penup_timer);

	tsc200x_update_pen_state(ts, 0, 0, 0);

	tsc200x_reset(ts);

	enable_irq(ts->irq);
	tsc200x_start_scan(ts);

out:
	mutex_unlock(&ts->mutex);
reschedule:
	/* re-arm the watchdog */
	schedule_delayed_work(&ts->esd_work,
			      round_jiffies_relative(
					msecs_to_jiffies(ts->esd_timeout)));
}

static int tsc200x_open(struct input_dev *input)
{
	struct tsc200x *ts = input_get_drvdata(input);

	mutex_lock(&ts->mutex);

	if (!ts->suspended)
		__tsc200x_enable(ts);

	ts->opened = true;

	mutex_unlock(&ts->mutex);

	return 0;
}

static void tsc200x_close(struct input_dev *input)
{
	struct tsc200x *ts = input_get_drvdata(input);

	mutex_lock(&ts->mutex);

	if (!ts->suspended)
		__tsc200x_disable(ts);

	ts->opened = false;

	mutex_unlock(&ts->mutex);
}

int tsc200x_probe(struct device *dev, int irq, const struct input_id *tsc_id,
		  struct regmap *regmap,
		  int (*tsc200x_cmd)(struct device *dev, u8 cmd))
{
	struct tsc200x *ts;
	struct input_dev *input_dev;
	u32 x_plate_ohm;
	u32 esd_timeout;
	int error;

	if (irq <= 0) {
		dev_err(dev, "no irq\n");
		return -ENODEV;
	}

	if (IS_ERR(regmap))
		return PTR_ERR(regmap);

	if (!tsc200x_cmd) {
		dev_err(dev, "no cmd function\n");
		return -ENODEV;
	}

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

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

	ts->irq = irq;
	ts->dev = dev;
	ts->idev = input_dev;
	ts->regmap = regmap;
	ts->tsc200x_cmd = tsc200x_cmd;

	error = device_property_read_u32(dev, "ti,x-plate-ohms", &x_plate_ohm);
	ts->x_plate_ohm = error ? TSC200X_DEF_RESISTOR : x_plate_ohm;

	error = device_property_read_u32(dev, "ti,esd-recovery-timeout-ms",
					 &esd_timeout);
	ts->esd_timeout = error ? 0 : esd_timeout;

	ts->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
	if (IS_ERR(ts->reset_gpio)) {
		error = PTR_ERR(ts->reset_gpio);
		dev_err(dev, "error acquiring reset gpio: %d\n", error);
		return error;
	}

	ts->vio = devm_regulator_get(dev, "vio");
	if (IS_ERR(ts->vio)) {
		error = PTR_ERR(ts->vio);
		dev_err(dev, "error acquiring vio regulator: %d", error);
		return error;
	}

	mutex_init(&ts->mutex);

	spin_lock_init(&ts->lock);
	timer_setup(&ts->penup_timer, tsc200x_penup_timer, 0);

	INIT_DELAYED_WORK(&ts->esd_work, tsc200x_esd_work);

	snprintf(ts->phys, sizeof(ts->phys),
		 "%s/input-ts", dev_name(dev));

	if (tsc_id->product == 2004) {
		input_dev->name = "TSC200X touchscreen";
	} else {
		input_dev->name = devm_kasprintf(dev, GFP_KERNEL,
						 "TSC%04d touchscreen",
						 tsc_id->product);
		if (!input_dev->name)
			return -ENOMEM;
	}

	input_dev->phys = ts->phys;
	input_dev->id = *tsc_id;

	input_dev->open = tsc200x_open;
	input_dev->close = tsc200x_close;

	input_set_drvdata(input_dev, ts);

	__set_bit(INPUT_PROP_DIRECT, input_dev->propbit);
	input_set_capability(input_dev, EV_KEY, BTN_TOUCH);

	input_set_abs_params(input_dev, ABS_X,
			     0, MAX_12BIT, TSC200X_DEF_X_FUZZ, 0);
	input_set_abs_params(input_dev, ABS_Y,
			     0, MAX_12BIT, TSC200X_DEF_Y_FUZZ, 0);
	input_set_abs_params(input_dev, ABS_PRESSURE,
			     0, MAX_12BIT, TSC200X_DEF_P_FUZZ, 0);

	touchscreen_parse_properties(input_dev, false, NULL);

	/* Ensure the touchscreen is off */
	tsc200x_stop_scan(ts);

	error = devm_request_threaded_irq(dev, irq, NULL,
					  tsc200x_irq_thread,
					  IRQF_TRIGGER_RISING | IRQF_ONESHOT,
					  "tsc200x", ts);
	if (error) {
		dev_err(dev, "Failed to request irq, err: %d\n", error);
		return error;
	}

	error = regulator_enable(ts->vio);
	if (error)
		return error;

	dev_set_drvdata(dev, ts);
	error = sysfs_create_group(&dev->kobj, &tsc200x_attr_group);
	if (error) {
		dev_err(dev,
			"Failed to create sysfs attributes, err: %d\n", error);
		goto disable_regulator;
	}

	error = input_register_device(ts->idev);
	if (error) {
		dev_err(dev,
			"Failed to register input device, err: %d\n", error);
		goto err_remove_sysfs;
	}

	irq_set_irq_wake(irq, 1);
	return 0;

err_remove_sysfs:
	sysfs_remove_group(&dev->kobj, &tsc200x_attr_group);
disable_regulator:
	regulator_disable(ts->vio);
	return error;
}
EXPORT_SYMBOL_GPL(tsc200x_probe);

int tsc200x_remove(struct device *dev)
{
	struct tsc200x *ts = dev_get_drvdata(dev);

	sysfs_remove_group(&dev->kobj, &tsc200x_attr_group);

	regulator_disable(ts->vio);

	return 0;
}
EXPORT_SYMBOL_GPL(tsc200x_remove);

static int __maybe_unused tsc200x_suspend(struct device *dev)
{
	struct tsc200x *ts = dev_get_drvdata(dev);

	mutex_lock(&ts->mutex);

	if (!ts->suspended && ts->opened)
		__tsc200x_disable(ts);

	ts->suspended = true;

	mutex_unlock(&ts->mutex);

	return 0;
}

static int __maybe_unused tsc200x_resume(struct device *dev)
{
	struct tsc200x *ts = dev_get_drvdata(dev);

	mutex_lock(&ts->mutex);

	if (ts->suspended && ts->opened)
		__tsc200x_enable(ts);

	ts->suspended = false;

	mutex_unlock(&ts->mutex);

	return 0;
}

SIMPLE_DEV_PM_OPS(tsc200x_pm_ops, tsc200x_suspend, tsc200x_resume);
EXPORT_SYMBOL_GPL(tsc200x_pm_ops);

MODULE_AUTHOR("Lauri Leukkunen <lauri.leukkunen@nokia.com>");
MODULE_DESCRIPTION("TSC200x Touchscreen Driver Core");
MODULE_LICENSE("GPL");