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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 <[email protected]>
10 * based on TSC2301 driver by Klaus K. Pedersen <[email protected]>
11 */
12
13#include <linux/export.h>
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/input.h>
17#include <linux/input/touchscreen.h>
18#include <linux/interrupt.h>
19#include <linux/delay.h>
20#include <linux/pm.h>
21#include <linux/of.h>
22#include <linux/regulator/consumer.h>
23#include <linux/regmap.h>
24#include <linux/gpio/consumer.h>
25#include "tsc200x-core.h"
26
27/*
28 * The touchscreen interface operates as follows:
29 *
30 * 1) Pen is pressed against the touchscreen.
31 * 2) TSC200X performs AD conversion.
32 * 3) After the conversion is done TSC200X drives DAV line down.
33 * 4) GPIO IRQ is received and tsc200x_irq_thread() is scheduled.
34 * 5) tsc200x_irq_thread() queues up a transfer to fetch the x, y, z1, z2
35 * values.
36 * 6) tsc200x_irq_thread() reports coordinates to input layer and sets up
37 * tsc200x_penup_timer() to be called after TSC200X_PENUP_TIME_MS (40ms).
38 * 7) When the penup timer expires, there have not been touch or DAV interrupts
39 * during the last 40ms which means the pen has been lifted.
40 *
41 * ESD recovery via a hardware reset is done if the TSC200X doesn't respond
42 * after a configurable period (in ms) of activity. If esd_timeout is 0, the
43 * watchdog is disabled.
44 */
45
46static const struct regmap_range tsc200x_writable_ranges[] = {
47 regmap_reg_range(TSC200X_REG_AUX_HIGH, TSC200X_REG_CFR2),
48};
49
50static const struct regmap_access_table tsc200x_writable_table = {
51 .yes_ranges = tsc200x_writable_ranges,
52 .n_yes_ranges = ARRAY_SIZE(tsc200x_writable_ranges),
53};
54
55const struct regmap_config tsc200x_regmap_config = {
56 .reg_bits = 8,
57 .val_bits = 16,
58 .reg_stride = 0x08,
59 .max_register = 0x78,
60 .read_flag_mask = TSC200X_REG_READ,
61 .write_flag_mask = TSC200X_REG_PND0,
62 .wr_table = &tsc200x_writable_table,
63 .use_single_read = true,
64 .use_single_write = true,
65};
66EXPORT_SYMBOL_GPL(tsc200x_regmap_config);
67
68struct tsc200x_data {
69 u16 x;
70 u16 y;
71 u16 z1;
72 u16 z2;
73} __packed;
74#define TSC200X_DATA_REGS 4
75
76struct tsc200x {
77 struct device *dev;
78 struct regmap *regmap;
79 __u16 bustype;
80
81 struct input_dev *idev;
82 char phys[32];
83
84 struct mutex mutex;
85
86 /* raw copy of previous x,y,z */
87 int in_x;
88 int in_y;
89 int in_z1;
90 int in_z2;
91
92 struct touchscreen_properties prop;
93
94 spinlock_t lock;
95 struct timer_list penup_timer;
96
97 unsigned int esd_timeout;
98 struct delayed_work esd_work;
99 unsigned long last_valid_interrupt;
100
101 unsigned int x_plate_ohm;
102
103 bool opened;
104 bool suspended;
105
106 bool pen_down;
107
108 struct gpio_desc *reset_gpio;
109 int (*tsc200x_cmd)(struct device *dev, u8 cmd);
110
111 int irq;
112 bool wake_irq_enabled;
113};
114
115static void tsc200x_update_pen_state(struct tsc200x *ts,
116 int x, int y, int pressure)
117{
118 if (pressure) {
119 touchscreen_report_pos(ts->idev, &ts->prop, x, y, false);
120 input_report_abs(ts->idev, ABS_PRESSURE, pressure);
121 if (!ts->pen_down) {
122 input_report_key(ts->idev, BTN_TOUCH, !!pressure);
123 ts->pen_down = true;
124 }
125 } else {
126 input_report_abs(ts->idev, ABS_PRESSURE, 0);
127 if (ts->pen_down) {
128 input_report_key(ts->idev, BTN_TOUCH, 0);
129 ts->pen_down = false;
130 }
131 }
132 input_sync(ts->idev);
133 dev_dbg(ts->dev, "point(%4d,%4d), pressure (%4d)\n", x, y,
134 pressure);
135}
136
137static irqreturn_t tsc200x_irq_thread(int irq, void *_ts)
138{
139 struct tsc200x *ts = _ts;
140 unsigned int pressure;
141 struct tsc200x_data tsdata;
142 int error;
143
144 /* read the coordinates */
145 error = regmap_bulk_read(ts->regmap, TSC200X_REG_X, &tsdata,
146 TSC200X_DATA_REGS);
147 if (unlikely(error))
148 goto out;
149
150 /* validate position */
151 if (unlikely(tsdata.x > MAX_12BIT || tsdata.y > MAX_12BIT))
152 goto out;
153
154 /* Skip reading if the pressure components are out of range */
155 if (unlikely(tsdata.z1 == 0 || tsdata.z2 > MAX_12BIT))
156 goto out;
157 if (unlikely(tsdata.z1 >= tsdata.z2))
158 goto out;
159
160 /*
161 * Skip point if this is a pen down with the exact same values as
162 * the value before pen-up - that implies SPI fed us stale data
163 */
164 if (!ts->pen_down &&
165 ts->in_x == tsdata.x && ts->in_y == tsdata.y &&
166 ts->in_z1 == tsdata.z1 && ts->in_z2 == tsdata.z2) {
167 goto out;
168 }
169
170 /*
171 * At this point we are happy we have a valid and useful reading.
172 * Remember it for later comparisons. We may now begin downsampling.
173 */
174 ts->in_x = tsdata.x;
175 ts->in_y = tsdata.y;
176 ts->in_z1 = tsdata.z1;
177 ts->in_z2 = tsdata.z2;
178
179 /* Compute touch pressure resistance using equation #1 */
180 pressure = tsdata.x * (tsdata.z2 - tsdata.z1) / tsdata.z1;
181 pressure = pressure * ts->x_plate_ohm / 4096;
182 if (unlikely(pressure > MAX_12BIT))
183 goto out;
184
185 scoped_guard(spinlock_irqsave, &ts->lock) {
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
191 ts->last_valid_interrupt = jiffies;
192out:
193 return IRQ_HANDLED;
194}
195
196static void tsc200x_penup_timer(struct timer_list *t)
197{
198 struct tsc200x *ts = timer_container_of(ts, t, penup_timer);
199
200 guard(spinlock_irqsave)(&ts->lock);
201 tsc200x_update_pen_state(ts, 0, 0, 0);
202}
203
204static void tsc200x_start_scan(struct tsc200x *ts)
205{
206 regmap_write(ts->regmap, TSC200X_REG_CFR0, TSC200X_CFR0_INITVALUE);
207 regmap_write(ts->regmap, TSC200X_REG_CFR1, TSC200X_CFR1_INITVALUE);
208 regmap_write(ts->regmap, TSC200X_REG_CFR2, TSC200X_CFR2_INITVALUE);
209 ts->tsc200x_cmd(ts->dev, TSC200X_CMD_NORMAL);
210}
211
212static void tsc200x_stop_scan(struct tsc200x *ts)
213{
214 ts->tsc200x_cmd(ts->dev, TSC200X_CMD_STOP);
215}
216
217static void tsc200x_reset(struct tsc200x *ts)
218{
219 if (ts->reset_gpio) {
220 gpiod_set_value_cansleep(ts->reset_gpio, 1);
221 usleep_range(100, 500); /* only 10us required */
222 gpiod_set_value_cansleep(ts->reset_gpio, 0);
223 }
224}
225
226/* must be called with ts->mutex held */
227static void __tsc200x_disable(struct tsc200x *ts)
228{
229 tsc200x_stop_scan(ts);
230
231 guard(disable_irq)(&ts->irq);
232
233 timer_delete_sync(&ts->penup_timer);
234 cancel_delayed_work_sync(&ts->esd_work);
235}
236
237/* must be called with ts->mutex held */
238static void __tsc200x_enable(struct tsc200x *ts)
239{
240 tsc200x_start_scan(ts);
241
242 if (ts->esd_timeout && ts->reset_gpio) {
243 ts->last_valid_interrupt = jiffies;
244 schedule_delayed_work(&ts->esd_work,
245 round_jiffies_relative(
246 msecs_to_jiffies(ts->esd_timeout)));
247 }
248}
249
250/*
251 * Test TSC200X communications via temp high register.
252 */
253static int tsc200x_do_selftest(struct tsc200x *ts)
254{
255 unsigned int temp_high_orig;
256 unsigned int temp_high_test;
257 unsigned int temp_high;
258 int error;
259
260 error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high_orig);
261 if (error) {
262 dev_warn(ts->dev, "selftest failed: read error %d\n", error);
263 return error;
264 }
265
266 temp_high_test = (temp_high_orig - 1) & MAX_12BIT;
267
268 error = regmap_write(ts->regmap, TSC200X_REG_TEMP_HIGH, temp_high_test);
269 if (error) {
270 dev_warn(ts->dev, "selftest failed: write error %d\n", error);
271 return error;
272 }
273
274 error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high);
275 if (error) {
276 dev_warn(ts->dev,
277 "selftest failed: read error %d after write\n", error);
278 return error;
279 }
280
281 /* hardware reset */
282 tsc200x_reset(ts);
283
284 if (temp_high != temp_high_test) {
285 dev_warn(ts->dev, "selftest failed: %d != %d\n",
286 temp_high, temp_high_test);
287 return -EINVAL;
288 }
289
290 /* test that the reset really happened */
291 error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high);
292 if (error) {
293 dev_warn(ts->dev,
294 "selftest failed: read error %d after reset\n", error);
295 return error;
296 }
297
298 if (temp_high != temp_high_orig) {
299 dev_warn(ts->dev, "selftest failed after reset: %d != %d\n",
300 temp_high, temp_high_orig);
301 return -EINVAL;
302 }
303
304 return 0;
305}
306
307static ssize_t tsc200x_selftest_show(struct device *dev,
308 struct device_attribute *attr,
309 char *buf)
310{
311 struct tsc200x *ts = dev_get_drvdata(dev);
312 int error;
313
314 scoped_guard(mutex, &ts->mutex) {
315 __tsc200x_disable(ts);
316
317 error = tsc200x_do_selftest(ts);
318
319 __tsc200x_enable(ts);
320 }
321
322 return sprintf(buf, "%d\n", !error);
323}
324
325static DEVICE_ATTR(selftest, S_IRUGO, tsc200x_selftest_show, NULL);
326
327static struct attribute *tsc200x_attrs[] = {
328 &dev_attr_selftest.attr,
329 NULL
330};
331
332static umode_t tsc200x_attr_is_visible(struct kobject *kobj,
333 struct attribute *attr, int n)
334{
335 struct device *dev = kobj_to_dev(kobj);
336 struct tsc200x *ts = dev_get_drvdata(dev);
337 umode_t mode = attr->mode;
338
339 if (attr == &dev_attr_selftest.attr) {
340 if (!ts->reset_gpio)
341 mode = 0;
342 }
343
344 return mode;
345}
346
347static const struct attribute_group tsc200x_attr_group = {
348 .is_visible = tsc200x_attr_is_visible,
349 .attrs = tsc200x_attrs,
350};
351
352const struct attribute_group *tsc200x_groups[] = {
353 &tsc200x_attr_group,
354 NULL
355};
356EXPORT_SYMBOL_GPL(tsc200x_groups);
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 /*
365 * If the mutex is taken, it means that disable or enable is in
366 * progress. In that case just reschedule the work. If the work
367 * is not needed, it will be canceled by disable.
368 */
369 scoped_guard(mutex_try, &ts->mutex) {
370 if (time_is_after_jiffies(ts->last_valid_interrupt +
371 msecs_to_jiffies(ts->esd_timeout)))
372 break;
373
374 /*
375 * We should be able to read register without disabling
376 * interrupts.
377 */
378 error = regmap_read(ts->regmap, TSC200X_REG_CFR0, &r);
379 if (!error &&
380 !((r ^ TSC200X_CFR0_INITVALUE) & TSC200X_CFR0_RW_MASK)) {
381 break;
382 }
383
384 /*
385 * If we could not read our known value from configuration
386 * register 0 then we should reset the controller as if from
387 * power-up and start scanning again.
388 */
389 dev_info(ts->dev, "TSC200X not responding - resetting\n");
390
391 scoped_guard(disable_irq, &ts->irq) {
392 timer_delete_sync(&ts->penup_timer);
393 tsc200x_update_pen_state(ts, 0, 0, 0);
394 tsc200x_reset(ts);
395 }
396
397 tsc200x_start_scan(ts);
398 }
399
400 /* re-arm the watchdog */
401 schedule_delayed_work(&ts->esd_work,
402 round_jiffies_relative(
403 msecs_to_jiffies(ts->esd_timeout)));
404}
405
406static int tsc200x_open(struct input_dev *input)
407{
408 struct tsc200x *ts = input_get_drvdata(input);
409
410 guard(mutex)(&ts->mutex);
411
412 if (!ts->suspended)
413 __tsc200x_enable(ts);
414
415 ts->opened = true;
416
417 return 0;
418}
419
420static void tsc200x_close(struct input_dev *input)
421{
422 struct tsc200x *ts = input_get_drvdata(input);
423
424 guard(mutex)(&ts->mutex);
425
426 if (!ts->suspended)
427 __tsc200x_disable(ts);
428
429 ts->opened = false;
430}
431
432int tsc200x_probe(struct device *dev, int irq, const struct input_id *tsc_id,
433 struct regmap *regmap,
434 int (*tsc200x_cmd)(struct device *dev, u8 cmd))
435{
436 struct tsc200x *ts;
437 struct input_dev *input_dev;
438 u32 x_plate_ohm;
439 u32 esd_timeout;
440 int error;
441
442 if (irq <= 0) {
443 dev_err(dev, "no irq\n");
444 return -ENODEV;
445 }
446
447 if (IS_ERR(regmap))
448 return PTR_ERR(regmap);
449
450 if (!tsc200x_cmd) {
451 dev_err(dev, "no cmd function\n");
452 return -ENODEV;
453 }
454
455 ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
456 if (!ts)
457 return -ENOMEM;
458
459 input_dev = devm_input_allocate_device(dev);
460 if (!input_dev)
461 return -ENOMEM;
462
463 ts->irq = irq;
464 ts->dev = dev;
465 ts->idev = input_dev;
466 ts->regmap = regmap;
467 ts->tsc200x_cmd = tsc200x_cmd;
468
469 error = device_property_read_u32(dev, "ti,x-plate-ohms", &x_plate_ohm);
470 ts->x_plate_ohm = error ? TSC200X_DEF_RESISTOR : x_plate_ohm;
471
472 error = device_property_read_u32(dev, "ti,esd-recovery-timeout-ms",
473 &esd_timeout);
474 ts->esd_timeout = error ? 0 : esd_timeout;
475
476 mutex_init(&ts->mutex);
477
478 spin_lock_init(&ts->lock);
479 timer_setup(&ts->penup_timer, tsc200x_penup_timer, 0);
480
481 INIT_DELAYED_WORK(&ts->esd_work, tsc200x_esd_work);
482
483 snprintf(ts->phys, sizeof(ts->phys),
484 "%s/input-ts", dev_name(dev));
485
486 if (tsc_id->product == 2004) {
487 input_dev->name = "TSC200X touchscreen";
488 } else {
489 input_dev->name = devm_kasprintf(dev, GFP_KERNEL,
490 "TSC%04d touchscreen",
491 tsc_id->product);
492 if (!input_dev->name)
493 return -ENOMEM;
494 }
495
496 input_dev->phys = ts->phys;
497 input_dev->id = *tsc_id;
498
499 input_dev->open = tsc200x_open;
500 input_dev->close = tsc200x_close;
501
502 input_set_drvdata(input_dev, ts);
503
504 __set_bit(INPUT_PROP_DIRECT, input_dev->propbit);
505 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
506
507 input_set_abs_params(input_dev, ABS_X,
508 0, MAX_12BIT, TSC200X_DEF_X_FUZZ, 0);
509 input_set_abs_params(input_dev, ABS_Y,
510 0, MAX_12BIT, TSC200X_DEF_Y_FUZZ, 0);
511 input_set_abs_params(input_dev, ABS_PRESSURE,
512 0, MAX_12BIT, TSC200X_DEF_P_FUZZ, 0);
513
514 touchscreen_parse_properties(input_dev, false, &ts->prop);
515
516 ts->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
517 error = PTR_ERR_OR_ZERO(ts->reset_gpio);
518 if (error) {
519 dev_err(dev, "error acquiring reset gpio: %d\n", error);
520 return error;
521 }
522
523 error = devm_regulator_get_enable(dev, "vio");
524 if (error) {
525 dev_err(dev, "error acquiring vio regulator: %d\n", error);
526 return error;
527 }
528
529 tsc200x_reset(ts);
530
531 /* Ensure the touchscreen is off */
532 tsc200x_stop_scan(ts);
533
534 error = devm_request_threaded_irq(dev, irq, NULL, tsc200x_irq_thread,
535 IRQF_ONESHOT, "tsc200x", ts);
536 if (error) {
537 dev_err(dev, "Failed to request irq, err: %d\n", error);
538 return error;
539 }
540
541 dev_set_drvdata(dev, ts);
542
543 error = input_register_device(ts->idev);
544 if (error) {
545 dev_err(dev,
546 "Failed to register input device, err: %d\n", error);
547 return error;
548 }
549
550 device_init_wakeup(dev,
551 device_property_read_bool(dev, "wakeup-source"));
552
553 return 0;
554}
555EXPORT_SYMBOL_GPL(tsc200x_probe);
556
557static int tsc200x_suspend(struct device *dev)
558{
559 struct tsc200x *ts = dev_get_drvdata(dev);
560
561 guard(mutex)(&ts->mutex);
562
563 if (!ts->suspended && ts->opened)
564 __tsc200x_disable(ts);
565
566 ts->suspended = true;
567
568 if (device_may_wakeup(dev))
569 ts->wake_irq_enabled = enable_irq_wake(ts->irq) == 0;
570
571 return 0;
572}
573
574static int tsc200x_resume(struct device *dev)
575{
576 struct tsc200x *ts = dev_get_drvdata(dev);
577
578 guard(mutex)(&ts->mutex);
579
580 if (ts->wake_irq_enabled) {
581 disable_irq_wake(ts->irq);
582 ts->wake_irq_enabled = false;
583 }
584
585 if (ts->suspended && ts->opened)
586 __tsc200x_enable(ts);
587
588 ts->suspended = false;
589
590 return 0;
591}
592
593EXPORT_GPL_SIMPLE_DEV_PM_OPS(tsc200x_pm_ops, tsc200x_suspend, tsc200x_resume);
594
595MODULE_AUTHOR("Lauri Leukkunen <[email protected]>");
596MODULE_DESCRIPTION("TSC200x Touchscreen Driver Core");
597MODULE_LICENSE("GPL");