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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * TSC2004/TSC2005 touchscreen driver core
4 *
5 * Copyright (C) 2006-2010 Nokia Corporation
6 * Copyright (C) 2015 QWERTY Embedded Design
7 * Copyright (C) 2015 EMAC Inc.
8 *
9 * Author: Lauri Leukkunen <lauri.leukkunen@nokia.com>
10 * based on TSC2301 driver by Klaus K. Pedersen <klaus.k.pedersen@nokia.com>
11 */
12
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/input.h>
16#include <linux/input/touchscreen.h>
17#include <linux/interrupt.h>
18#include <linux/delay.h>
19#include <linux/pm.h>
20#include <linux/of.h>
21#include <linux/regulator/consumer.h>
22#include <linux/regmap.h>
23#include <linux/gpio/consumer.h>
24#include "tsc200x-core.h"
25
26/*
27 * The touchscreen interface operates as follows:
28 *
29 * 1) Pen is pressed against the touchscreen.
30 * 2) TSC200X performs AD conversion.
31 * 3) After the conversion is done TSC200X drives DAV line down.
32 * 4) GPIO IRQ is received and tsc200x_irq_thread() is scheduled.
33 * 5) tsc200x_irq_thread() queues up a transfer to fetch the x, y, z1, z2
34 * values.
35 * 6) tsc200x_irq_thread() reports coordinates to input layer and sets up
36 * tsc200x_penup_timer() to be called after TSC200X_PENUP_TIME_MS (40ms).
37 * 7) When the penup timer expires, there have not been touch or DAV interrupts
38 * during the last 40ms which means the pen has been lifted.
39 *
40 * ESD recovery via a hardware reset is done if the TSC200X doesn't respond
41 * after a configurable period (in ms) of activity. If esd_timeout is 0, the
42 * watchdog is disabled.
43 */
44
45static const struct regmap_range tsc200x_writable_ranges[] = {
46 regmap_reg_range(TSC200X_REG_AUX_HIGH, TSC200X_REG_CFR2),
47};
48
49static const struct regmap_access_table tsc200x_writable_table = {
50 .yes_ranges = tsc200x_writable_ranges,
51 .n_yes_ranges = ARRAY_SIZE(tsc200x_writable_ranges),
52};
53
54const struct regmap_config tsc200x_regmap_config = {
55 .reg_bits = 8,
56 .val_bits = 16,
57 .reg_stride = 0x08,
58 .max_register = 0x78,
59 .read_flag_mask = TSC200X_REG_READ,
60 .write_flag_mask = TSC200X_REG_PND0,
61 .wr_table = &tsc200x_writable_table,
62 .use_single_read = true,
63 .use_single_write = true,
64};
65EXPORT_SYMBOL_GPL(tsc200x_regmap_config);
66
67struct tsc200x_data {
68 u16 x;
69 u16 y;
70 u16 z1;
71 u16 z2;
72} __packed;
73#define TSC200X_DATA_REGS 4
74
75struct tsc200x {
76 struct device *dev;
77 struct regmap *regmap;
78 __u16 bustype;
79
80 struct input_dev *idev;
81 char phys[32];
82
83 struct mutex mutex;
84
85 /* raw copy of previous x,y,z */
86 int in_x;
87 int in_y;
88 int in_z1;
89 int in_z2;
90
91 spinlock_t lock;
92 struct timer_list penup_timer;
93
94 unsigned int esd_timeout;
95 struct delayed_work esd_work;
96 unsigned long last_valid_interrupt;
97
98 unsigned int x_plate_ohm;
99
100 bool opened;
101 bool suspended;
102
103 bool pen_down;
104
105 struct regulator *vio;
106
107 struct gpio_desc *reset_gpio;
108 int (*tsc200x_cmd)(struct device *dev, u8 cmd);
109 int irq;
110};
111
112static void tsc200x_update_pen_state(struct tsc200x *ts,
113 int x, int y, int pressure)
114{
115 if (pressure) {
116 input_report_abs(ts->idev, ABS_X, x);
117 input_report_abs(ts->idev, ABS_Y, y);
118 input_report_abs(ts->idev, ABS_PRESSURE, pressure);
119 if (!ts->pen_down) {
120 input_report_key(ts->idev, BTN_TOUCH, !!pressure);
121 ts->pen_down = true;
122 }
123 } else {
124 input_report_abs(ts->idev, ABS_PRESSURE, 0);
125 if (ts->pen_down) {
126 input_report_key(ts->idev, BTN_TOUCH, 0);
127 ts->pen_down = false;
128 }
129 }
130 input_sync(ts->idev);
131 dev_dbg(ts->dev, "point(%4d,%4d), pressure (%4d)\n", x, y,
132 pressure);
133}
134
135static irqreturn_t tsc200x_irq_thread(int irq, void *_ts)
136{
137 struct tsc200x *ts = _ts;
138 unsigned long flags;
139 unsigned int pressure;
140 struct tsc200x_data tsdata;
141 int error;
142
143 /* read the coordinates */
144 error = regmap_bulk_read(ts->regmap, TSC200X_REG_X, &tsdata,
145 TSC200X_DATA_REGS);
146 if (unlikely(error))
147 goto out;
148
149 /* validate position */
150 if (unlikely(tsdata.x > MAX_12BIT || tsdata.y > MAX_12BIT))
151 goto out;
152
153 /* Skip reading if the pressure components are out of range */
154 if (unlikely(tsdata.z1 == 0 || tsdata.z2 > MAX_12BIT))
155 goto out;
156 if (unlikely(tsdata.z1 >= tsdata.z2))
157 goto out;
158
159 /*
160 * Skip point if this is a pen down with the exact same values as
161 * the value before pen-up - that implies SPI fed us stale data
162 */
163 if (!ts->pen_down &&
164 ts->in_x == tsdata.x && ts->in_y == tsdata.y &&
165 ts->in_z1 == tsdata.z1 && ts->in_z2 == tsdata.z2) {
166 goto out;
167 }
168
169 /*
170 * At this point we are happy we have a valid and useful reading.
171 * Remember it for later comparisons. We may now begin downsampling.
172 */
173 ts->in_x = tsdata.x;
174 ts->in_y = tsdata.y;
175 ts->in_z1 = tsdata.z1;
176 ts->in_z2 = tsdata.z2;
177
178 /* Compute touch pressure resistance using equation #1 */
179 pressure = tsdata.x * (tsdata.z2 - tsdata.z1) / tsdata.z1;
180 pressure = pressure * ts->x_plate_ohm / 4096;
181 if (unlikely(pressure > MAX_12BIT))
182 goto out;
183
184 spin_lock_irqsave(&ts->lock, flags);
185
186 tsc200x_update_pen_state(ts, tsdata.x, tsdata.y, pressure);
187 mod_timer(&ts->penup_timer,
188 jiffies + msecs_to_jiffies(TSC200X_PENUP_TIME_MS));
189
190 spin_unlock_irqrestore(&ts->lock, flags);
191
192 ts->last_valid_interrupt = jiffies;
193out:
194 return IRQ_HANDLED;
195}
196
197static void tsc200x_penup_timer(struct timer_list *t)
198{
199 struct tsc200x *ts = from_timer(ts, t, penup_timer);
200 unsigned long flags;
201
202 spin_lock_irqsave(&ts->lock, flags);
203 tsc200x_update_pen_state(ts, 0, 0, 0);
204 spin_unlock_irqrestore(&ts->lock, flags);
205}
206
207static void tsc200x_start_scan(struct tsc200x *ts)
208{
209 regmap_write(ts->regmap, TSC200X_REG_CFR0, TSC200X_CFR0_INITVALUE);
210 regmap_write(ts->regmap, TSC200X_REG_CFR1, TSC200X_CFR1_INITVALUE);
211 regmap_write(ts->regmap, TSC200X_REG_CFR2, TSC200X_CFR2_INITVALUE);
212 ts->tsc200x_cmd(ts->dev, TSC200X_CMD_NORMAL);
213}
214
215static void tsc200x_stop_scan(struct tsc200x *ts)
216{
217 ts->tsc200x_cmd(ts->dev, TSC200X_CMD_STOP);
218}
219
220static void tsc200x_reset(struct tsc200x *ts)
221{
222 if (ts->reset_gpio) {
223 gpiod_set_value_cansleep(ts->reset_gpio, 1);
224 usleep_range(100, 500); /* only 10us required */
225 gpiod_set_value_cansleep(ts->reset_gpio, 0);
226 }
227}
228
229/* must be called with ts->mutex held */
230static void __tsc200x_disable(struct tsc200x *ts)
231{
232 tsc200x_stop_scan(ts);
233
234 disable_irq(ts->irq);
235 del_timer_sync(&ts->penup_timer);
236
237 cancel_delayed_work_sync(&ts->esd_work);
238
239 enable_irq(ts->irq);
240}
241
242/* must be called with ts->mutex held */
243static void __tsc200x_enable(struct tsc200x *ts)
244{
245 tsc200x_start_scan(ts);
246
247 if (ts->esd_timeout && ts->reset_gpio) {
248 ts->last_valid_interrupt = jiffies;
249 schedule_delayed_work(&ts->esd_work,
250 round_jiffies_relative(
251 msecs_to_jiffies(ts->esd_timeout)));
252 }
253}
254
255static ssize_t tsc200x_selftest_show(struct device *dev,
256 struct device_attribute *attr,
257 char *buf)
258{
259 struct tsc200x *ts = dev_get_drvdata(dev);
260 unsigned int temp_high;
261 unsigned int temp_high_orig;
262 unsigned int temp_high_test;
263 bool success = true;
264 int error;
265
266 mutex_lock(&ts->mutex);
267
268 /*
269 * Test TSC200X communications via temp high register.
270 */
271 __tsc200x_disable(ts);
272
273 error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high_orig);
274 if (error) {
275 dev_warn(dev, "selftest failed: read error %d\n", error);
276 success = false;
277 goto out;
278 }
279
280 temp_high_test = (temp_high_orig - 1) & MAX_12BIT;
281
282 error = regmap_write(ts->regmap, TSC200X_REG_TEMP_HIGH, temp_high_test);
283 if (error) {
284 dev_warn(dev, "selftest failed: write error %d\n", error);
285 success = false;
286 goto out;
287 }
288
289 error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high);
290 if (error) {
291 dev_warn(dev, "selftest failed: read error %d after write\n",
292 error);
293 success = false;
294 goto out;
295 }
296
297 if (temp_high != temp_high_test) {
298 dev_warn(dev, "selftest failed: %d != %d\n",
299 temp_high, temp_high_test);
300 success = false;
301 }
302
303 /* hardware reset */
304 tsc200x_reset(ts);
305
306 if (!success)
307 goto out;
308
309 /* test that the reset really happened */
310 error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high);
311 if (error) {
312 dev_warn(dev, "selftest failed: read error %d after reset\n",
313 error);
314 success = false;
315 goto out;
316 }
317
318 if (temp_high != temp_high_orig) {
319 dev_warn(dev, "selftest failed after reset: %d != %d\n",
320 temp_high, temp_high_orig);
321 success = false;
322 }
323
324out:
325 __tsc200x_enable(ts);
326 mutex_unlock(&ts->mutex);
327
328 return sprintf(buf, "%d\n", success);
329}
330
331static DEVICE_ATTR(selftest, S_IRUGO, tsc200x_selftest_show, NULL);
332
333static struct attribute *tsc200x_attrs[] = {
334 &dev_attr_selftest.attr,
335 NULL
336};
337
338static umode_t tsc200x_attr_is_visible(struct kobject *kobj,
339 struct attribute *attr, int n)
340{
341 struct device *dev = container_of(kobj, struct device, kobj);
342 struct tsc200x *ts = dev_get_drvdata(dev);
343 umode_t mode = attr->mode;
344
345 if (attr == &dev_attr_selftest.attr) {
346 if (!ts->reset_gpio)
347 mode = 0;
348 }
349
350 return mode;
351}
352
353static const struct attribute_group tsc200x_attr_group = {
354 .is_visible = tsc200x_attr_is_visible,
355 .attrs = tsc200x_attrs,
356};
357
358static void tsc200x_esd_work(struct work_struct *work)
359{
360 struct tsc200x *ts = container_of(work, struct tsc200x, esd_work.work);
361 int error;
362 unsigned int r;
363
364 if (!mutex_trylock(&ts->mutex)) {
365 /*
366 * If the mutex is taken, it means that disable or enable is in
367 * progress. In that case just reschedule the work. If the work
368 * is not needed, it will be canceled by disable.
369 */
370 goto reschedule;
371 }
372
373 if (time_is_after_jiffies(ts->last_valid_interrupt +
374 msecs_to_jiffies(ts->esd_timeout)))
375 goto out;
376
377 /* We should be able to read register without disabling interrupts. */
378 error = regmap_read(ts->regmap, TSC200X_REG_CFR0, &r);
379 if (!error &&
380 !((r ^ TSC200X_CFR0_INITVALUE) & TSC200X_CFR0_RW_MASK)) {
381 goto out;
382 }
383
384 /*
385 * If we could not read our known value from configuration register 0
386 * then we should reset the controller as if from power-up and start
387 * scanning again.
388 */
389 dev_info(ts->dev, "TSC200X not responding - resetting\n");
390
391 disable_irq(ts->irq);
392 del_timer_sync(&ts->penup_timer);
393
394 tsc200x_update_pen_state(ts, 0, 0, 0);
395
396 tsc200x_reset(ts);
397
398 enable_irq(ts->irq);
399 tsc200x_start_scan(ts);
400
401out:
402 mutex_unlock(&ts->mutex);
403reschedule:
404 /* re-arm the watchdog */
405 schedule_delayed_work(&ts->esd_work,
406 round_jiffies_relative(
407 msecs_to_jiffies(ts->esd_timeout)));
408}
409
410static int tsc200x_open(struct input_dev *input)
411{
412 struct tsc200x *ts = input_get_drvdata(input);
413
414 mutex_lock(&ts->mutex);
415
416 if (!ts->suspended)
417 __tsc200x_enable(ts);
418
419 ts->opened = true;
420
421 mutex_unlock(&ts->mutex);
422
423 return 0;
424}
425
426static void tsc200x_close(struct input_dev *input)
427{
428 struct tsc200x *ts = input_get_drvdata(input);
429
430 mutex_lock(&ts->mutex);
431
432 if (!ts->suspended)
433 __tsc200x_disable(ts);
434
435 ts->opened = false;
436
437 mutex_unlock(&ts->mutex);
438}
439
440int tsc200x_probe(struct device *dev, int irq, const struct input_id *tsc_id,
441 struct regmap *regmap,
442 int (*tsc200x_cmd)(struct device *dev, u8 cmd))
443{
444 struct tsc200x *ts;
445 struct input_dev *input_dev;
446 u32 x_plate_ohm;
447 u32 esd_timeout;
448 int error;
449
450 if (irq <= 0) {
451 dev_err(dev, "no irq\n");
452 return -ENODEV;
453 }
454
455 if (IS_ERR(regmap))
456 return PTR_ERR(regmap);
457
458 if (!tsc200x_cmd) {
459 dev_err(dev, "no cmd function\n");
460 return -ENODEV;
461 }
462
463 ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
464 if (!ts)
465 return -ENOMEM;
466
467 input_dev = devm_input_allocate_device(dev);
468 if (!input_dev)
469 return -ENOMEM;
470
471 ts->irq = irq;
472 ts->dev = dev;
473 ts->idev = input_dev;
474 ts->regmap = regmap;
475 ts->tsc200x_cmd = tsc200x_cmd;
476
477 error = device_property_read_u32(dev, "ti,x-plate-ohms", &x_plate_ohm);
478 ts->x_plate_ohm = error ? TSC200X_DEF_RESISTOR : x_plate_ohm;
479
480 error = device_property_read_u32(dev, "ti,esd-recovery-timeout-ms",
481 &esd_timeout);
482 ts->esd_timeout = error ? 0 : esd_timeout;
483
484 ts->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
485 if (IS_ERR(ts->reset_gpio)) {
486 error = PTR_ERR(ts->reset_gpio);
487 dev_err(dev, "error acquiring reset gpio: %d\n", error);
488 return error;
489 }
490
491 ts->vio = devm_regulator_get(dev, "vio");
492 if (IS_ERR(ts->vio)) {
493 error = PTR_ERR(ts->vio);
494 dev_err(dev, "error acquiring vio regulator: %d", error);
495 return error;
496 }
497
498 mutex_init(&ts->mutex);
499
500 spin_lock_init(&ts->lock);
501 timer_setup(&ts->penup_timer, tsc200x_penup_timer, 0);
502
503 INIT_DELAYED_WORK(&ts->esd_work, tsc200x_esd_work);
504
505 snprintf(ts->phys, sizeof(ts->phys),
506 "%s/input-ts", dev_name(dev));
507
508 if (tsc_id->product == 2004) {
509 input_dev->name = "TSC200X touchscreen";
510 } else {
511 input_dev->name = devm_kasprintf(dev, GFP_KERNEL,
512 "TSC%04d touchscreen",
513 tsc_id->product);
514 if (!input_dev->name)
515 return -ENOMEM;
516 }
517
518 input_dev->phys = ts->phys;
519 input_dev->id = *tsc_id;
520
521 input_dev->open = tsc200x_open;
522 input_dev->close = tsc200x_close;
523
524 input_set_drvdata(input_dev, ts);
525
526 __set_bit(INPUT_PROP_DIRECT, input_dev->propbit);
527 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
528
529 input_set_abs_params(input_dev, ABS_X,
530 0, MAX_12BIT, TSC200X_DEF_X_FUZZ, 0);
531 input_set_abs_params(input_dev, ABS_Y,
532 0, MAX_12BIT, TSC200X_DEF_Y_FUZZ, 0);
533 input_set_abs_params(input_dev, ABS_PRESSURE,
534 0, MAX_12BIT, TSC200X_DEF_P_FUZZ, 0);
535
536 touchscreen_parse_properties(input_dev, false, NULL);
537
538 /* Ensure the touchscreen is off */
539 tsc200x_stop_scan(ts);
540
541 error = devm_request_threaded_irq(dev, irq, NULL,
542 tsc200x_irq_thread,
543 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
544 "tsc200x", ts);
545 if (error) {
546 dev_err(dev, "Failed to request irq, err: %d\n", error);
547 return error;
548 }
549
550 error = regulator_enable(ts->vio);
551 if (error)
552 return error;
553
554 dev_set_drvdata(dev, ts);
555 error = sysfs_create_group(&dev->kobj, &tsc200x_attr_group);
556 if (error) {
557 dev_err(dev,
558 "Failed to create sysfs attributes, err: %d\n", error);
559 goto disable_regulator;
560 }
561
562 error = input_register_device(ts->idev);
563 if (error) {
564 dev_err(dev,
565 "Failed to register input device, err: %d\n", error);
566 goto err_remove_sysfs;
567 }
568
569 irq_set_irq_wake(irq, 1);
570 return 0;
571
572err_remove_sysfs:
573 sysfs_remove_group(&dev->kobj, &tsc200x_attr_group);
574disable_regulator:
575 regulator_disable(ts->vio);
576 return error;
577}
578EXPORT_SYMBOL_GPL(tsc200x_probe);
579
580int tsc200x_remove(struct device *dev)
581{
582 struct tsc200x *ts = dev_get_drvdata(dev);
583
584 sysfs_remove_group(&dev->kobj, &tsc200x_attr_group);
585
586 regulator_disable(ts->vio);
587
588 return 0;
589}
590EXPORT_SYMBOL_GPL(tsc200x_remove);
591
592static int __maybe_unused tsc200x_suspend(struct device *dev)
593{
594 struct tsc200x *ts = dev_get_drvdata(dev);
595
596 mutex_lock(&ts->mutex);
597
598 if (!ts->suspended && ts->opened)
599 __tsc200x_disable(ts);
600
601 ts->suspended = true;
602
603 mutex_unlock(&ts->mutex);
604
605 return 0;
606}
607
608static int __maybe_unused tsc200x_resume(struct device *dev)
609{
610 struct tsc200x *ts = dev_get_drvdata(dev);
611
612 mutex_lock(&ts->mutex);
613
614 if (ts->suspended && ts->opened)
615 __tsc200x_enable(ts);
616
617 ts->suspended = false;
618
619 mutex_unlock(&ts->mutex);
620
621 return 0;
622}
623
624SIMPLE_DEV_PM_OPS(tsc200x_pm_ops, tsc200x_suspend, tsc200x_resume);
625EXPORT_SYMBOL_GPL(tsc200x_pm_ops);
626
627MODULE_AUTHOR("Lauri Leukkunen <lauri.leukkunen@nokia.com>");
628MODULE_DESCRIPTION("TSC200x Touchscreen Driver Core");
629MODULE_LICENSE("GPL");