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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 struct touchscreen_properties prop;
92
93 spinlock_t lock;
94 struct timer_list penup_timer;
95
96 unsigned int esd_timeout;
97 struct delayed_work esd_work;
98 unsigned long last_valid_interrupt;
99
100 unsigned int x_plate_ohm;
101
102 bool opened;
103 bool suspended;
104
105 bool pen_down;
106
107 struct gpio_desc *reset_gpio;
108 int (*tsc200x_cmd)(struct device *dev, u8 cmd);
109
110 int irq;
111 bool wake_irq_enabled;
112};
113
114static void tsc200x_update_pen_state(struct tsc200x *ts,
115 int x, int y, int pressure)
116{
117 if (pressure) {
118 touchscreen_report_pos(ts->idev, &ts->prop, x, y, false);
119 input_report_abs(ts->idev, ABS_PRESSURE, pressure);
120 if (!ts->pen_down) {
121 input_report_key(ts->idev, BTN_TOUCH, !!pressure);
122 ts->pen_down = true;
123 }
124 } else {
125 input_report_abs(ts->idev, ABS_PRESSURE, 0);
126 if (ts->pen_down) {
127 input_report_key(ts->idev, BTN_TOUCH, 0);
128 ts->pen_down = false;
129 }
130 }
131 input_sync(ts->idev);
132 dev_dbg(ts->dev, "point(%4d,%4d), pressure (%4d)\n", x, y,
133 pressure);
134}
135
136static irqreturn_t tsc200x_irq_thread(int irq, void *_ts)
137{
138 struct tsc200x *ts = _ts;
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 scoped_guard(spinlock_irqsave, &ts->lock) {
185 tsc200x_update_pen_state(ts, tsdata.x, tsdata.y, pressure);
186 mod_timer(&ts->penup_timer,
187 jiffies + msecs_to_jiffies(TSC200X_PENUP_TIME_MS));
188 }
189
190 ts->last_valid_interrupt = jiffies;
191out:
192 return IRQ_HANDLED;
193}
194
195static void tsc200x_penup_timer(struct timer_list *t)
196{
197 struct tsc200x *ts = from_timer(ts, t, penup_timer);
198
199 guard(spinlock_irqsave)(&ts->lock);
200 tsc200x_update_pen_state(ts, 0, 0, 0);
201}
202
203static void tsc200x_start_scan(struct tsc200x *ts)
204{
205 regmap_write(ts->regmap, TSC200X_REG_CFR0, TSC200X_CFR0_INITVALUE);
206 regmap_write(ts->regmap, TSC200X_REG_CFR1, TSC200X_CFR1_INITVALUE);
207 regmap_write(ts->regmap, TSC200X_REG_CFR2, TSC200X_CFR2_INITVALUE);
208 ts->tsc200x_cmd(ts->dev, TSC200X_CMD_NORMAL);
209}
210
211static void tsc200x_stop_scan(struct tsc200x *ts)
212{
213 ts->tsc200x_cmd(ts->dev, TSC200X_CMD_STOP);
214}
215
216static void tsc200x_reset(struct tsc200x *ts)
217{
218 if (ts->reset_gpio) {
219 gpiod_set_value_cansleep(ts->reset_gpio, 1);
220 usleep_range(100, 500); /* only 10us required */
221 gpiod_set_value_cansleep(ts->reset_gpio, 0);
222 }
223}
224
225/* must be called with ts->mutex held */
226static void __tsc200x_disable(struct tsc200x *ts)
227{
228 tsc200x_stop_scan(ts);
229
230 guard(disable_irq)(&ts->irq);
231
232 del_timer_sync(&ts->penup_timer);
233 cancel_delayed_work_sync(&ts->esd_work);
234}
235
236/* must be called with ts->mutex held */
237static void __tsc200x_enable(struct tsc200x *ts)
238{
239 tsc200x_start_scan(ts);
240
241 if (ts->esd_timeout && ts->reset_gpio) {
242 ts->last_valid_interrupt = jiffies;
243 schedule_delayed_work(&ts->esd_work,
244 round_jiffies_relative(
245 msecs_to_jiffies(ts->esd_timeout)));
246 }
247}
248
249/*
250 * Test TSC200X communications via temp high register.
251 */
252static int tsc200x_do_selftest(struct tsc200x *ts)
253{
254 unsigned int temp_high_orig;
255 unsigned int temp_high_test;
256 unsigned int temp_high;
257 int error;
258
259 error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high_orig);
260 if (error) {
261 dev_warn(ts->dev, "selftest failed: read error %d\n", error);
262 return error;
263 }
264
265 temp_high_test = (temp_high_orig - 1) & MAX_12BIT;
266
267 error = regmap_write(ts->regmap, TSC200X_REG_TEMP_HIGH, temp_high_test);
268 if (error) {
269 dev_warn(ts->dev, "selftest failed: write error %d\n", error);
270 return error;
271 }
272
273 error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high);
274 if (error) {
275 dev_warn(ts->dev,
276 "selftest failed: read error %d after write\n", error);
277 return error;
278 }
279
280 /* hardware reset */
281 tsc200x_reset(ts);
282
283 if (temp_high != temp_high_test) {
284 dev_warn(ts->dev, "selftest failed: %d != %d\n",
285 temp_high, temp_high_test);
286 return -EINVAL;
287 }
288
289 /* test that the reset really happened */
290 error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high);
291 if (error) {
292 dev_warn(ts->dev,
293 "selftest failed: read error %d after reset\n", error);
294 return error;
295 }
296
297 if (temp_high != temp_high_orig) {
298 dev_warn(ts->dev, "selftest failed after reset: %d != %d\n",
299 temp_high, temp_high_orig);
300 return -EINVAL;
301 }
302
303 return 0;
304}
305
306static ssize_t tsc200x_selftest_show(struct device *dev,
307 struct device_attribute *attr,
308 char *buf)
309{
310 struct tsc200x *ts = dev_get_drvdata(dev);
311 int error;
312
313 scoped_guard(mutex, &ts->mutex) {
314 __tsc200x_disable(ts);
315
316 error = tsc200x_do_selftest(ts);
317
318 __tsc200x_enable(ts);
319 }
320
321 return sprintf(buf, "%d\n", !error);
322}
323
324static DEVICE_ATTR(selftest, S_IRUGO, tsc200x_selftest_show, NULL);
325
326static struct attribute *tsc200x_attrs[] = {
327 &dev_attr_selftest.attr,
328 NULL
329};
330
331static umode_t tsc200x_attr_is_visible(struct kobject *kobj,
332 struct attribute *attr, int n)
333{
334 struct device *dev = kobj_to_dev(kobj);
335 struct tsc200x *ts = dev_get_drvdata(dev);
336 umode_t mode = attr->mode;
337
338 if (attr == &dev_attr_selftest.attr) {
339 if (!ts->reset_gpio)
340 mode = 0;
341 }
342
343 return mode;
344}
345
346static const struct attribute_group tsc200x_attr_group = {
347 .is_visible = tsc200x_attr_is_visible,
348 .attrs = tsc200x_attrs,
349};
350
351const struct attribute_group *tsc200x_groups[] = {
352 &tsc200x_attr_group,
353 NULL
354};
355EXPORT_SYMBOL_GPL(tsc200x_groups);
356
357static void tsc200x_esd_work(struct work_struct *work)
358{
359 struct tsc200x *ts = container_of(work, struct tsc200x, esd_work.work);
360 int error;
361 unsigned int r;
362
363 /*
364 * If the mutex is taken, it means that disable or enable is in
365 * progress. In that case just reschedule the work. If the work
366 * is not needed, it will be canceled by disable.
367 */
368 scoped_guard(mutex_try, &ts->mutex) {
369 if (time_is_after_jiffies(ts->last_valid_interrupt +
370 msecs_to_jiffies(ts->esd_timeout)))
371 break;
372
373 /*
374 * We should be able to read register without disabling
375 * interrupts.
376 */
377 error = regmap_read(ts->regmap, TSC200X_REG_CFR0, &r);
378 if (!error &&
379 !((r ^ TSC200X_CFR0_INITVALUE) & TSC200X_CFR0_RW_MASK)) {
380 break;
381 }
382
383 /*
384 * If we could not read our known value from configuration
385 * register 0 then we should reset the controller as if from
386 * power-up and start scanning again.
387 */
388 dev_info(ts->dev, "TSC200X not responding - resetting\n");
389
390 scoped_guard(disable_irq, &ts->irq) {
391 del_timer_sync(&ts->penup_timer);
392 tsc200x_update_pen_state(ts, 0, 0, 0);
393 tsc200x_reset(ts);
394 }
395
396 tsc200x_start_scan(ts);
397 }
398
399 /* re-arm the watchdog */
400 schedule_delayed_work(&ts->esd_work,
401 round_jiffies_relative(
402 msecs_to_jiffies(ts->esd_timeout)));
403}
404
405static int tsc200x_open(struct input_dev *input)
406{
407 struct tsc200x *ts = input_get_drvdata(input);
408
409 guard(mutex)(&ts->mutex);
410
411 if (!ts->suspended)
412 __tsc200x_enable(ts);
413
414 ts->opened = true;
415
416 return 0;
417}
418
419static void tsc200x_close(struct input_dev *input)
420{
421 struct tsc200x *ts = input_get_drvdata(input);
422
423 guard(mutex)(&ts->mutex);
424
425 if (!ts->suspended)
426 __tsc200x_disable(ts);
427
428 ts->opened = false;
429}
430
431int tsc200x_probe(struct device *dev, int irq, const struct input_id *tsc_id,
432 struct regmap *regmap,
433 int (*tsc200x_cmd)(struct device *dev, u8 cmd))
434{
435 struct tsc200x *ts;
436 struct input_dev *input_dev;
437 u32 x_plate_ohm;
438 u32 esd_timeout;
439 int error;
440
441 if (irq <= 0) {
442 dev_err(dev, "no irq\n");
443 return -ENODEV;
444 }
445
446 if (IS_ERR(regmap))
447 return PTR_ERR(regmap);
448
449 if (!tsc200x_cmd) {
450 dev_err(dev, "no cmd function\n");
451 return -ENODEV;
452 }
453
454 ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
455 if (!ts)
456 return -ENOMEM;
457
458 input_dev = devm_input_allocate_device(dev);
459 if (!input_dev)
460 return -ENOMEM;
461
462 ts->irq = irq;
463 ts->dev = dev;
464 ts->idev = input_dev;
465 ts->regmap = regmap;
466 ts->tsc200x_cmd = tsc200x_cmd;
467
468 error = device_property_read_u32(dev, "ti,x-plate-ohms", &x_plate_ohm);
469 ts->x_plate_ohm = error ? TSC200X_DEF_RESISTOR : x_plate_ohm;
470
471 error = device_property_read_u32(dev, "ti,esd-recovery-timeout-ms",
472 &esd_timeout);
473 ts->esd_timeout = error ? 0 : esd_timeout;
474
475 mutex_init(&ts->mutex);
476
477 spin_lock_init(&ts->lock);
478 timer_setup(&ts->penup_timer, tsc200x_penup_timer, 0);
479
480 INIT_DELAYED_WORK(&ts->esd_work, tsc200x_esd_work);
481
482 snprintf(ts->phys, sizeof(ts->phys),
483 "%s/input-ts", dev_name(dev));
484
485 if (tsc_id->product == 2004) {
486 input_dev->name = "TSC200X touchscreen";
487 } else {
488 input_dev->name = devm_kasprintf(dev, GFP_KERNEL,
489 "TSC%04d touchscreen",
490 tsc_id->product);
491 if (!input_dev->name)
492 return -ENOMEM;
493 }
494
495 input_dev->phys = ts->phys;
496 input_dev->id = *tsc_id;
497
498 input_dev->open = tsc200x_open;
499 input_dev->close = tsc200x_close;
500
501 input_set_drvdata(input_dev, ts);
502
503 __set_bit(INPUT_PROP_DIRECT, input_dev->propbit);
504 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
505
506 input_set_abs_params(input_dev, ABS_X,
507 0, MAX_12BIT, TSC200X_DEF_X_FUZZ, 0);
508 input_set_abs_params(input_dev, ABS_Y,
509 0, MAX_12BIT, TSC200X_DEF_Y_FUZZ, 0);
510 input_set_abs_params(input_dev, ABS_PRESSURE,
511 0, MAX_12BIT, TSC200X_DEF_P_FUZZ, 0);
512
513 touchscreen_parse_properties(input_dev, false, &ts->prop);
514
515 ts->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
516 error = PTR_ERR_OR_ZERO(ts->reset_gpio);
517 if (error) {
518 dev_err(dev, "error acquiring reset gpio: %d\n", error);
519 return error;
520 }
521
522 error = devm_regulator_get_enable(dev, "vio");
523 if (error) {
524 dev_err(dev, "error acquiring vio regulator: %d\n", error);
525 return error;
526 }
527
528 tsc200x_reset(ts);
529
530 /* Ensure the touchscreen is off */
531 tsc200x_stop_scan(ts);
532
533 error = devm_request_threaded_irq(dev, irq, NULL, tsc200x_irq_thread,
534 IRQF_ONESHOT, "tsc200x", ts);
535 if (error) {
536 dev_err(dev, "Failed to request irq, err: %d\n", error);
537 return error;
538 }
539
540 dev_set_drvdata(dev, ts);
541
542 error = input_register_device(ts->idev);
543 if (error) {
544 dev_err(dev,
545 "Failed to register input device, err: %d\n", error);
546 return error;
547 }
548
549 device_init_wakeup(dev,
550 device_property_read_bool(dev, "wakeup-source"));
551
552 return 0;
553}
554EXPORT_SYMBOL_GPL(tsc200x_probe);
555
556static int tsc200x_suspend(struct device *dev)
557{
558 struct tsc200x *ts = dev_get_drvdata(dev);
559
560 guard(mutex)(&ts->mutex);
561
562 if (!ts->suspended && ts->opened)
563 __tsc200x_disable(ts);
564
565 ts->suspended = true;
566
567 if (device_may_wakeup(dev))
568 ts->wake_irq_enabled = enable_irq_wake(ts->irq) == 0;
569
570 return 0;
571}
572
573static int tsc200x_resume(struct device *dev)
574{
575 struct tsc200x *ts = dev_get_drvdata(dev);
576
577 guard(mutex)(&ts->mutex);
578
579 if (ts->wake_irq_enabled) {
580 disable_irq_wake(ts->irq);
581 ts->wake_irq_enabled = false;
582 }
583
584 if (ts->suspended && ts->opened)
585 __tsc200x_enable(ts);
586
587 ts->suspended = false;
588
589 return 0;
590}
591
592EXPORT_GPL_SIMPLE_DEV_PM_OPS(tsc200x_pm_ops, tsc200x_suspend, tsc200x_resume);
593
594MODULE_AUTHOR("Lauri Leukkunen <lauri.leukkunen@nokia.com>");
595MODULE_DESCRIPTION("TSC200x Touchscreen Driver Core");
596MODULE_LICENSE("GPL");