1/*
2 * TSC2004/TSC2005 touchscreen driver core
3 *
4 * Copyright (C) 2006-2010 Nokia Corporation
5 * Copyright (C) 2015 QWERTY Embedded Design
6 * Copyright (C) 2015 EMAC Inc.
7 *
8 * Author: Lauri Leukkunen <lauri.leukkunen@nokia.com>
9 * based on TSC2301 driver by Klaus K. Pedersen <klaus.k.pedersen@nokia.com>
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
20 */
21
22#include <linux/kernel.h>
23#include <linux/module.h>
24#include <linux/input.h>
25#include <linux/input/touchscreen.h>
26#include <linux/interrupt.h>
27#include <linux/delay.h>
28#include <linux/pm.h>
29#include <linux/of.h>
30#include <linux/regulator/consumer.h>
31#include <linux/regmap.h>
32#include <linux/gpio/consumer.h>
33#include "tsc200x-core.h"
34
35/*
36 * The touchscreen interface operates as follows:
37 *
38 * 1) Pen is pressed against the touchscreen.
39 * 2) TSC200X performs AD conversion.
40 * 3) After the conversion is done TSC200X drives DAV line down.
41 * 4) GPIO IRQ is received and tsc200x_irq_thread() is scheduled.
42 * 5) tsc200x_irq_thread() queues up a transfer to fetch the x, y, z1, z2
43 * values.
44 * 6) tsc200x_irq_thread() reports coordinates to input layer and sets up
45 * tsc200x_penup_timer() to be called after TSC200X_PENUP_TIME_MS (40ms).
46 * 7) When the penup timer expires, there have not been touch or DAV interrupts
47 * during the last 40ms which means the pen has been lifted.
48 *
49 * ESD recovery via a hardware reset is done if the TSC200X doesn't respond
50 * after a configurable period (in ms) of activity. If esd_timeout is 0, the
51 * watchdog is disabled.
52 */
53
54static const struct regmap_range tsc200x_writable_ranges[] = {
55 regmap_reg_range(TSC200X_REG_AUX_HIGH, TSC200X_REG_CFR2),
56};
57
58static const struct regmap_access_table tsc200x_writable_table = {
59 .yes_ranges = tsc200x_writable_ranges,
60 .n_yes_ranges = ARRAY_SIZE(tsc200x_writable_ranges),
61};
62
63const struct regmap_config tsc200x_regmap_config = {
64 .reg_bits = 8,
65 .val_bits = 16,
66 .reg_stride = 0x08,
67 .max_register = 0x78,
68 .read_flag_mask = TSC200X_REG_READ,
69 .write_flag_mask = TSC200X_REG_PND0,
70 .wr_table = &tsc200x_writable_table,
71 .use_single_read = true,
72 .use_single_write = true,
73};
74EXPORT_SYMBOL_GPL(tsc200x_regmap_config);
75
76struct tsc200x_data {
77 u16 x;
78 u16 y;
79 u16 z1;
80 u16 z2;
81} __packed;
82#define TSC200X_DATA_REGS 4
83
84struct tsc200x {
85 struct device *dev;
86 struct regmap *regmap;
87 __u16 bustype;
88
89 struct input_dev *idev;
90 char phys[32];
91
92 struct mutex mutex;
93
94 /* raw copy of previous x,y,z */
95 int in_x;
96 int in_y;
97 int in_z1;
98 int in_z2;
99
100 spinlock_t lock;
101 struct timer_list penup_timer;
102
103 unsigned int esd_timeout;
104 struct delayed_work esd_work;
105 unsigned long last_valid_interrupt;
106
107 unsigned int x_plate_ohm;
108
109 bool opened;
110 bool suspended;
111
112 bool pen_down;
113
114 struct regulator *vio;
115
116 struct gpio_desc *reset_gpio;
117 int (*tsc200x_cmd)(struct device *dev, u8 cmd);
118 int irq;
119};
120
121static void tsc200x_update_pen_state(struct tsc200x *ts,
122 int x, int y, int pressure)
123{
124 if (pressure) {
125 input_report_abs(ts->idev, ABS_X, x);
126 input_report_abs(ts->idev, ABS_Y, y);
127 input_report_abs(ts->idev, ABS_PRESSURE, pressure);
128 if (!ts->pen_down) {
129 input_report_key(ts->idev, BTN_TOUCH, !!pressure);
130 ts->pen_down = true;
131 }
132 } else {
133 input_report_abs(ts->idev, ABS_PRESSURE, 0);
134 if (ts->pen_down) {
135 input_report_key(ts->idev, BTN_TOUCH, 0);
136 ts->pen_down = false;
137 }
138 }
139 input_sync(ts->idev);
140 dev_dbg(ts->dev, "point(%4d,%4d), pressure (%4d)\n", x, y,
141 pressure);
142}
143
144static irqreturn_t tsc200x_irq_thread(int irq, void *_ts)
145{
146 struct tsc200x *ts = _ts;
147 unsigned long flags;
148 unsigned int pressure;
149 struct tsc200x_data tsdata;
150 int error;
151
152 /* read the coordinates */
153 error = regmap_bulk_read(ts->regmap, TSC200X_REG_X, &tsdata,
154 TSC200X_DATA_REGS);
155 if (unlikely(error))
156 goto out;
157
158 /* validate position */
159 if (unlikely(tsdata.x > MAX_12BIT || tsdata.y > MAX_12BIT))
160 goto out;
161
162 /* Skip reading if the pressure components are out of range */
163 if (unlikely(tsdata.z1 == 0 || tsdata.z2 > MAX_12BIT))
164 goto out;
165 if (unlikely(tsdata.z1 >= tsdata.z2))
166 goto out;
167
168 /*
169 * Skip point if this is a pen down with the exact same values as
170 * the value before pen-up - that implies SPI fed us stale data
171 */
172 if (!ts->pen_down &&
173 ts->in_x == tsdata.x && ts->in_y == tsdata.y &&
174 ts->in_z1 == tsdata.z1 && ts->in_z2 == tsdata.z2) {
175 goto out;
176 }
177
178 /*
179 * At this point we are happy we have a valid and useful reading.
180 * Remember it for later comparisons. We may now begin downsampling.
181 */
182 ts->in_x = tsdata.x;
183 ts->in_y = tsdata.y;
184 ts->in_z1 = tsdata.z1;
185 ts->in_z2 = tsdata.z2;
186
187 /* Compute touch pressure resistance using equation #1 */
188 pressure = tsdata.x * (tsdata.z2 - tsdata.z1) / tsdata.z1;
189 pressure = pressure * ts->x_plate_ohm / 4096;
190 if (unlikely(pressure > MAX_12BIT))
191 goto out;
192
193 spin_lock_irqsave(&ts->lock, flags);
194
195 tsc200x_update_pen_state(ts, tsdata.x, tsdata.y, pressure);
196 mod_timer(&ts->penup_timer,
197 jiffies + msecs_to_jiffies(TSC200X_PENUP_TIME_MS));
198
199 spin_unlock_irqrestore(&ts->lock, flags);
200
201 ts->last_valid_interrupt = jiffies;
202out:
203 return IRQ_HANDLED;
204}
205
206static void tsc200x_penup_timer(struct timer_list *t)
207{
208 struct tsc200x *ts = from_timer(ts, t, penup_timer);
209 unsigned long flags;
210
211 spin_lock_irqsave(&ts->lock, flags);
212 tsc200x_update_pen_state(ts, 0, 0, 0);
213 spin_unlock_irqrestore(&ts->lock, flags);
214}
215
216static void tsc200x_start_scan(struct tsc200x *ts)
217{
218 regmap_write(ts->regmap, TSC200X_REG_CFR0, TSC200X_CFR0_INITVALUE);
219 regmap_write(ts->regmap, TSC200X_REG_CFR1, TSC200X_CFR1_INITVALUE);
220 regmap_write(ts->regmap, TSC200X_REG_CFR2, TSC200X_CFR2_INITVALUE);
221 ts->tsc200x_cmd(ts->dev, TSC200X_CMD_NORMAL);
222}
223
224static void tsc200x_stop_scan(struct tsc200x *ts)
225{
226 ts->tsc200x_cmd(ts->dev, TSC200X_CMD_STOP);
227}
228
229static void tsc200x_reset(struct tsc200x *ts)
230{
231 if (ts->reset_gpio) {
232 gpiod_set_value_cansleep(ts->reset_gpio, 1);
233 usleep_range(100, 500); /* only 10us required */
234 gpiod_set_value_cansleep(ts->reset_gpio, 0);
235 }
236}
237
238/* must be called with ts->mutex held */
239static void __tsc200x_disable(struct tsc200x *ts)
240{
241 tsc200x_stop_scan(ts);
242
243 disable_irq(ts->irq);
244 del_timer_sync(&ts->penup_timer);
245
246 cancel_delayed_work_sync(&ts->esd_work);
247
248 enable_irq(ts->irq);
249}
250
251/* must be called with ts->mutex held */
252static void __tsc200x_enable(struct tsc200x *ts)
253{
254 tsc200x_start_scan(ts);
255
256 if (ts->esd_timeout && ts->reset_gpio) {
257 ts->last_valid_interrupt = jiffies;
258 schedule_delayed_work(&ts->esd_work,
259 round_jiffies_relative(
260 msecs_to_jiffies(ts->esd_timeout)));
261 }
262}
263
264static ssize_t tsc200x_selftest_show(struct device *dev,
265 struct device_attribute *attr,
266 char *buf)
267{
268 struct tsc200x *ts = dev_get_drvdata(dev);
269 unsigned int temp_high;
270 unsigned int temp_high_orig;
271 unsigned int temp_high_test;
272 bool success = true;
273 int error;
274
275 mutex_lock(&ts->mutex);
276
277 /*
278 * Test TSC200X communications via temp high register.
279 */
280 __tsc200x_disable(ts);
281
282 error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high_orig);
283 if (error) {
284 dev_warn(dev, "selftest failed: read error %d\n", error);
285 success = false;
286 goto out;
287 }
288
289 temp_high_test = (temp_high_orig - 1) & MAX_12BIT;
290
291 error = regmap_write(ts->regmap, TSC200X_REG_TEMP_HIGH, temp_high_test);
292 if (error) {
293 dev_warn(dev, "selftest failed: write error %d\n", error);
294 success = false;
295 goto out;
296 }
297
298 error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high);
299 if (error) {
300 dev_warn(dev, "selftest failed: read error %d after write\n",
301 error);
302 success = false;
303 goto out;
304 }
305
306 if (temp_high != temp_high_test) {
307 dev_warn(dev, "selftest failed: %d != %d\n",
308 temp_high, temp_high_test);
309 success = false;
310 }
311
312 /* hardware reset */
313 tsc200x_reset(ts);
314
315 if (!success)
316 goto out;
317
318 /* test that the reset really happened */
319 error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high);
320 if (error) {
321 dev_warn(dev, "selftest failed: read error %d after reset\n",
322 error);
323 success = false;
324 goto out;
325 }
326
327 if (temp_high != temp_high_orig) {
328 dev_warn(dev, "selftest failed after reset: %d != %d\n",
329 temp_high, temp_high_orig);
330 success = false;
331 }
332
333out:
334 __tsc200x_enable(ts);
335 mutex_unlock(&ts->mutex);
336
337 return sprintf(buf, "%d\n", success);
338}
339
340static DEVICE_ATTR(selftest, S_IRUGO, tsc200x_selftest_show, NULL);
341
342static struct attribute *tsc200x_attrs[] = {
343 &dev_attr_selftest.attr,
344 NULL
345};
346
347static umode_t tsc200x_attr_is_visible(struct kobject *kobj,
348 struct attribute *attr, int n)
349{
350 struct device *dev = container_of(kobj, struct device, kobj);
351 struct tsc200x *ts = dev_get_drvdata(dev);
352 umode_t mode = attr->mode;
353
354 if (attr == &dev_attr_selftest.attr) {
355 if (!ts->reset_gpio)
356 mode = 0;
357 }
358
359 return mode;
360}
361
362static const struct attribute_group tsc200x_attr_group = {
363 .is_visible = tsc200x_attr_is_visible,
364 .attrs = tsc200x_attrs,
365};
366
367static void tsc200x_esd_work(struct work_struct *work)
368{
369 struct tsc200x *ts = container_of(work, struct tsc200x, esd_work.work);
370 int error;
371 unsigned int r;
372
373 if (!mutex_trylock(&ts->mutex)) {
374 /*
375 * If the mutex is taken, it means that disable or enable is in
376 * progress. In that case just reschedule the work. If the work
377 * is not needed, it will be canceled by disable.
378 */
379 goto reschedule;
380 }
381
382 if (time_is_after_jiffies(ts->last_valid_interrupt +
383 msecs_to_jiffies(ts->esd_timeout)))
384 goto out;
385
386 /* We should be able to read register without disabling interrupts. */
387 error = regmap_read(ts->regmap, TSC200X_REG_CFR0, &r);
388 if (!error &&
389 !((r ^ TSC200X_CFR0_INITVALUE) & TSC200X_CFR0_RW_MASK)) {
390 goto out;
391 }
392
393 /*
394 * If we could not read our known value from configuration register 0
395 * then we should reset the controller as if from power-up and start
396 * scanning again.
397 */
398 dev_info(ts->dev, "TSC200X not responding - resetting\n");
399
400 disable_irq(ts->irq);
401 del_timer_sync(&ts->penup_timer);
402
403 tsc200x_update_pen_state(ts, 0, 0, 0);
404
405 tsc200x_reset(ts);
406
407 enable_irq(ts->irq);
408 tsc200x_start_scan(ts);
409
410out:
411 mutex_unlock(&ts->mutex);
412reschedule:
413 /* re-arm the watchdog */
414 schedule_delayed_work(&ts->esd_work,
415 round_jiffies_relative(
416 msecs_to_jiffies(ts->esd_timeout)));
417}
418
419static int tsc200x_open(struct input_dev *input)
420{
421 struct tsc200x *ts = input_get_drvdata(input);
422
423 mutex_lock(&ts->mutex);
424
425 if (!ts->suspended)
426 __tsc200x_enable(ts);
427
428 ts->opened = true;
429
430 mutex_unlock(&ts->mutex);
431
432 return 0;
433}
434
435static void tsc200x_close(struct input_dev *input)
436{
437 struct tsc200x *ts = input_get_drvdata(input);
438
439 mutex_lock(&ts->mutex);
440
441 if (!ts->suspended)
442 __tsc200x_disable(ts);
443
444 ts->opened = false;
445
446 mutex_unlock(&ts->mutex);
447}
448
449int tsc200x_probe(struct device *dev, int irq, const struct input_id *tsc_id,
450 struct regmap *regmap,
451 int (*tsc200x_cmd)(struct device *dev, u8 cmd))
452{
453 struct tsc200x *ts;
454 struct input_dev *input_dev;
455 u32 x_plate_ohm;
456 u32 esd_timeout;
457 int error;
458
459 if (irq <= 0) {
460 dev_err(dev, "no irq\n");
461 return -ENODEV;
462 }
463
464 if (IS_ERR(regmap))
465 return PTR_ERR(regmap);
466
467 if (!tsc200x_cmd) {
468 dev_err(dev, "no cmd function\n");
469 return -ENODEV;
470 }
471
472 ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
473 if (!ts)
474 return -ENOMEM;
475
476 input_dev = devm_input_allocate_device(dev);
477 if (!input_dev)
478 return -ENOMEM;
479
480 ts->irq = irq;
481 ts->dev = dev;
482 ts->idev = input_dev;
483 ts->regmap = regmap;
484 ts->tsc200x_cmd = tsc200x_cmd;
485
486 error = device_property_read_u32(dev, "ti,x-plate-ohms", &x_plate_ohm);
487 ts->x_plate_ohm = error ? TSC200X_DEF_RESISTOR : x_plate_ohm;
488
489 error = device_property_read_u32(dev, "ti,esd-recovery-timeout-ms",
490 &esd_timeout);
491 ts->esd_timeout = error ? 0 : esd_timeout;
492
493 ts->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
494 if (IS_ERR(ts->reset_gpio)) {
495 error = PTR_ERR(ts->reset_gpio);
496 dev_err(dev, "error acquiring reset gpio: %d\n", error);
497 return error;
498 }
499
500 ts->vio = devm_regulator_get(dev, "vio");
501 if (IS_ERR(ts->vio)) {
502 error = PTR_ERR(ts->vio);
503 dev_err(dev, "error acquiring vio regulator: %d", error);
504 return error;
505 }
506
507 mutex_init(&ts->mutex);
508
509 spin_lock_init(&ts->lock);
510 timer_setup(&ts->penup_timer, tsc200x_penup_timer, 0);
511
512 INIT_DELAYED_WORK(&ts->esd_work, tsc200x_esd_work);
513
514 snprintf(ts->phys, sizeof(ts->phys),
515 "%s/input-ts", dev_name(dev));
516
517 if (tsc_id->product == 2004) {
518 input_dev->name = "TSC200X touchscreen";
519 } else {
520 input_dev->name = devm_kasprintf(dev, GFP_KERNEL,
521 "TSC%04d touchscreen",
522 tsc_id->product);
523 if (!input_dev->name)
524 return -ENOMEM;
525 }
526
527 input_dev->phys = ts->phys;
528 input_dev->id = *tsc_id;
529
530 input_dev->open = tsc200x_open;
531 input_dev->close = tsc200x_close;
532
533 input_set_drvdata(input_dev, ts);
534
535 __set_bit(INPUT_PROP_DIRECT, input_dev->propbit);
536 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
537
538 input_set_abs_params(input_dev, ABS_X,
539 0, MAX_12BIT, TSC200X_DEF_X_FUZZ, 0);
540 input_set_abs_params(input_dev, ABS_Y,
541 0, MAX_12BIT, TSC200X_DEF_Y_FUZZ, 0);
542 input_set_abs_params(input_dev, ABS_PRESSURE,
543 0, MAX_12BIT, TSC200X_DEF_P_FUZZ, 0);
544
545 touchscreen_parse_properties(input_dev, false, NULL);
546
547 /* Ensure the touchscreen is off */
548 tsc200x_stop_scan(ts);
549
550 error = devm_request_threaded_irq(dev, irq, NULL,
551 tsc200x_irq_thread,
552 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
553 "tsc200x", ts);
554 if (error) {
555 dev_err(dev, "Failed to request irq, err: %d\n", error);
556 return error;
557 }
558
559 error = regulator_enable(ts->vio);
560 if (error)
561 return error;
562
563 dev_set_drvdata(dev, ts);
564 error = sysfs_create_group(&dev->kobj, &tsc200x_attr_group);
565 if (error) {
566 dev_err(dev,
567 "Failed to create sysfs attributes, err: %d\n", error);
568 goto disable_regulator;
569 }
570
571 error = input_register_device(ts->idev);
572 if (error) {
573 dev_err(dev,
574 "Failed to register input device, err: %d\n", error);
575 goto err_remove_sysfs;
576 }
577
578 irq_set_irq_wake(irq, 1);
579 return 0;
580
581err_remove_sysfs:
582 sysfs_remove_group(&dev->kobj, &tsc200x_attr_group);
583disable_regulator:
584 regulator_disable(ts->vio);
585 return error;
586}
587EXPORT_SYMBOL_GPL(tsc200x_probe);
588
589int tsc200x_remove(struct device *dev)
590{
591 struct tsc200x *ts = dev_get_drvdata(dev);
592
593 sysfs_remove_group(&dev->kobj, &tsc200x_attr_group);
594
595 regulator_disable(ts->vio);
596
597 return 0;
598}
599EXPORT_SYMBOL_GPL(tsc200x_remove);
600
601static int __maybe_unused tsc200x_suspend(struct device *dev)
602{
603 struct tsc200x *ts = dev_get_drvdata(dev);
604
605 mutex_lock(&ts->mutex);
606
607 if (!ts->suspended && ts->opened)
608 __tsc200x_disable(ts);
609
610 ts->suspended = true;
611
612 mutex_unlock(&ts->mutex);
613
614 return 0;
615}
616
617static int __maybe_unused tsc200x_resume(struct device *dev)
618{
619 struct tsc200x *ts = dev_get_drvdata(dev);
620
621 mutex_lock(&ts->mutex);
622
623 if (ts->suspended && ts->opened)
624 __tsc200x_enable(ts);
625
626 ts->suspended = false;
627
628 mutex_unlock(&ts->mutex);
629
630 return 0;
631}
632
633SIMPLE_DEV_PM_OPS(tsc200x_pm_ops, tsc200x_suspend, tsc200x_resume);
634EXPORT_SYMBOL_GPL(tsc200x_pm_ops);
635
636MODULE_AUTHOR("Lauri Leukkunen <lauri.leukkunen@nokia.com>");
637MODULE_DESCRIPTION("TSC200x Touchscreen Driver Core");
638MODULE_LICENSE("GPL");
639