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
45 static const struct regmap_range tsc200x_writable_ranges[] = {
46 regmap_reg_range(TSC200X_REG_AUX_HIGH, TSC200X_REG_CFR2),
47 };
48
49 static 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
54 const 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 };
65 EXPORT_SYMBOL_GPL(tsc200x_regmap_config);
66
67 struct tsc200x_data {
68 u16 x;
69 u16 y;
70 u16 z1;
71 u16 z2;
72 } __packed;
73 #define TSC200X_DATA_REGS 4
74
75 struct 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 regulator *vio;
108
109 struct gpio_desc *reset_gpio;
110 int (*tsc200x_cmd)(struct device *dev, u8 cmd);
111 int irq;
112 };
113
tsc200x_update_pen_state(struct tsc200x * ts,int x,int y,int pressure)114 static 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
tsc200x_irq_thread(int irq,void * _ts)136 static irqreturn_t tsc200x_irq_thread(int irq, void *_ts)
137 {
138 struct tsc200x *ts = _ts;
139 unsigned long flags;
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 spin_lock_irqsave(&ts->lock, flags);
186
187 tsc200x_update_pen_state(ts, tsdata.x, tsdata.y, pressure);
188 mod_timer(&ts->penup_timer,
189 jiffies + msecs_to_jiffies(TSC200X_PENUP_TIME_MS));
190
191 spin_unlock_irqrestore(&ts->lock, flags);
192
193 ts->last_valid_interrupt = jiffies;
194 out:
195 return IRQ_HANDLED;
196 }
197
tsc200x_penup_timer(struct timer_list * t)198 static void tsc200x_penup_timer(struct timer_list *t)
199 {
200 struct tsc200x *ts = from_timer(ts, t, penup_timer);
201 unsigned long flags;
202
203 spin_lock_irqsave(&ts->lock, flags);
204 tsc200x_update_pen_state(ts, 0, 0, 0);
205 spin_unlock_irqrestore(&ts->lock, flags);
206 }
207
tsc200x_start_scan(struct tsc200x * ts)208 static void tsc200x_start_scan(struct tsc200x *ts)
209 {
210 regmap_write(ts->regmap, TSC200X_REG_CFR0, TSC200X_CFR0_INITVALUE);
211 regmap_write(ts->regmap, TSC200X_REG_CFR1, TSC200X_CFR1_INITVALUE);
212 regmap_write(ts->regmap, TSC200X_REG_CFR2, TSC200X_CFR2_INITVALUE);
213 ts->tsc200x_cmd(ts->dev, TSC200X_CMD_NORMAL);
214 }
215
tsc200x_stop_scan(struct tsc200x * ts)216 static void tsc200x_stop_scan(struct tsc200x *ts)
217 {
218 ts->tsc200x_cmd(ts->dev, TSC200X_CMD_STOP);
219 }
220
tsc200x_reset(struct tsc200x * ts)221 static void tsc200x_reset(struct tsc200x *ts)
222 {
223 if (ts->reset_gpio) {
224 gpiod_set_value_cansleep(ts->reset_gpio, 1);
225 usleep_range(100, 500); /* only 10us required */
226 gpiod_set_value_cansleep(ts->reset_gpio, 0);
227 }
228 }
229
230 /* must be called with ts->mutex held */
__tsc200x_disable(struct tsc200x * ts)231 static void __tsc200x_disable(struct tsc200x *ts)
232 {
233 tsc200x_stop_scan(ts);
234
235 disable_irq(ts->irq);
236 del_timer_sync(&ts->penup_timer);
237
238 cancel_delayed_work_sync(&ts->esd_work);
239
240 enable_irq(ts->irq);
241 }
242
243 /* must be called with ts->mutex held */
__tsc200x_enable(struct tsc200x * ts)244 static void __tsc200x_enable(struct tsc200x *ts)
245 {
246 tsc200x_start_scan(ts);
247
248 if (ts->esd_timeout && ts->reset_gpio) {
249 ts->last_valid_interrupt = jiffies;
250 schedule_delayed_work(&ts->esd_work,
251 round_jiffies_relative(
252 msecs_to_jiffies(ts->esd_timeout)));
253 }
254 }
255
tsc200x_selftest_show(struct device * dev,struct device_attribute * attr,char * buf)256 static ssize_t tsc200x_selftest_show(struct device *dev,
257 struct device_attribute *attr,
258 char *buf)
259 {
260 struct tsc200x *ts = dev_get_drvdata(dev);
261 unsigned int temp_high;
262 unsigned int temp_high_orig;
263 unsigned int temp_high_test;
264 bool success = true;
265 int error;
266
267 mutex_lock(&ts->mutex);
268
269 /*
270 * Test TSC200X communications via temp high register.
271 */
272 __tsc200x_disable(ts);
273
274 error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high_orig);
275 if (error) {
276 dev_warn(dev, "selftest failed: read error %d\n", error);
277 success = false;
278 goto out;
279 }
280
281 temp_high_test = (temp_high_orig - 1) & MAX_12BIT;
282
283 error = regmap_write(ts->regmap, TSC200X_REG_TEMP_HIGH, temp_high_test);
284 if (error) {
285 dev_warn(dev, "selftest failed: write error %d\n", error);
286 success = false;
287 goto out;
288 }
289
290 error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high);
291 if (error) {
292 dev_warn(dev, "selftest failed: read error %d after write\n",
293 error);
294 success = false;
295 goto out;
296 }
297
298 if (temp_high != temp_high_test) {
299 dev_warn(dev, "selftest failed: %d != %d\n",
300 temp_high, temp_high_test);
301 success = false;
302 }
303
304 /* hardware reset */
305 tsc200x_reset(ts);
306
307 if (!success)
308 goto out;
309
310 /* test that the reset really happened */
311 error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high);
312 if (error) {
313 dev_warn(dev, "selftest failed: read error %d after reset\n",
314 error);
315 success = false;
316 goto out;
317 }
318
319 if (temp_high != temp_high_orig) {
320 dev_warn(dev, "selftest failed after reset: %d != %d\n",
321 temp_high, temp_high_orig);
322 success = false;
323 }
324
325 out:
326 __tsc200x_enable(ts);
327 mutex_unlock(&ts->mutex);
328
329 return sprintf(buf, "%d\n", success);
330 }
331
332 static DEVICE_ATTR(selftest, S_IRUGO, tsc200x_selftest_show, NULL);
333
334 static struct attribute *tsc200x_attrs[] = {
335 &dev_attr_selftest.attr,
336 NULL
337 };
338
tsc200x_attr_is_visible(struct kobject * kobj,struct attribute * attr,int n)339 static umode_t tsc200x_attr_is_visible(struct kobject *kobj,
340 struct attribute *attr, int n)
341 {
342 struct device *dev = kobj_to_dev(kobj);
343 struct tsc200x *ts = dev_get_drvdata(dev);
344 umode_t mode = attr->mode;
345
346 if (attr == &dev_attr_selftest.attr) {
347 if (!ts->reset_gpio)
348 mode = 0;
349 }
350
351 return mode;
352 }
353
354 static const struct attribute_group tsc200x_attr_group = {
355 .is_visible = tsc200x_attr_is_visible,
356 .attrs = tsc200x_attrs,
357 };
358
tsc200x_esd_work(struct work_struct * work)359 static void tsc200x_esd_work(struct work_struct *work)
360 {
361 struct tsc200x *ts = container_of(work, struct tsc200x, esd_work.work);
362 int error;
363 unsigned int r;
364
365 if (!mutex_trylock(&ts->mutex)) {
366 /*
367 * If the mutex is taken, it means that disable or enable is in
368 * progress. In that case just reschedule the work. If the work
369 * is not needed, it will be canceled by disable.
370 */
371 goto reschedule;
372 }
373
374 if (time_is_after_jiffies(ts->last_valid_interrupt +
375 msecs_to_jiffies(ts->esd_timeout)))
376 goto out;
377
378 /* We should be able to read register without disabling interrupts. */
379 error = regmap_read(ts->regmap, TSC200X_REG_CFR0, &r);
380 if (!error &&
381 !((r ^ TSC200X_CFR0_INITVALUE) & TSC200X_CFR0_RW_MASK)) {
382 goto out;
383 }
384
385 /*
386 * If we could not read our known value from configuration register 0
387 * then we should reset the controller as if from power-up and start
388 * scanning again.
389 */
390 dev_info(ts->dev, "TSC200X not responding - resetting\n");
391
392 disable_irq(ts->irq);
393 del_timer_sync(&ts->penup_timer);
394
395 tsc200x_update_pen_state(ts, 0, 0, 0);
396
397 tsc200x_reset(ts);
398
399 enable_irq(ts->irq);
400 tsc200x_start_scan(ts);
401
402 out:
403 mutex_unlock(&ts->mutex);
404 reschedule:
405 /* re-arm the watchdog */
406 schedule_delayed_work(&ts->esd_work,
407 round_jiffies_relative(
408 msecs_to_jiffies(ts->esd_timeout)));
409 }
410
tsc200x_open(struct input_dev * input)411 static int tsc200x_open(struct input_dev *input)
412 {
413 struct tsc200x *ts = input_get_drvdata(input);
414
415 mutex_lock(&ts->mutex);
416
417 if (!ts->suspended)
418 __tsc200x_enable(ts);
419
420 ts->opened = true;
421
422 mutex_unlock(&ts->mutex);
423
424 return 0;
425 }
426
tsc200x_close(struct input_dev * input)427 static void tsc200x_close(struct input_dev *input)
428 {
429 struct tsc200x *ts = input_get_drvdata(input);
430
431 mutex_lock(&ts->mutex);
432
433 if (!ts->suspended)
434 __tsc200x_disable(ts);
435
436 ts->opened = false;
437
438 mutex_unlock(&ts->mutex);
439 }
440
tsc200x_probe(struct device * dev,int irq,const struct input_id * tsc_id,struct regmap * regmap,int (* tsc200x_cmd)(struct device * dev,u8 cmd))441 int tsc200x_probe(struct device *dev, int irq, const struct input_id *tsc_id,
442 struct regmap *regmap,
443 int (*tsc200x_cmd)(struct device *dev, u8 cmd))
444 {
445 struct tsc200x *ts;
446 struct input_dev *input_dev;
447 u32 x_plate_ohm;
448 u32 esd_timeout;
449 int error;
450
451 if (irq <= 0) {
452 dev_err(dev, "no irq\n");
453 return -ENODEV;
454 }
455
456 if (IS_ERR(regmap))
457 return PTR_ERR(regmap);
458
459 if (!tsc200x_cmd) {
460 dev_err(dev, "no cmd function\n");
461 return -ENODEV;
462 }
463
464 ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
465 if (!ts)
466 return -ENOMEM;
467
468 input_dev = devm_input_allocate_device(dev);
469 if (!input_dev)
470 return -ENOMEM;
471
472 ts->irq = irq;
473 ts->dev = dev;
474 ts->idev = input_dev;
475 ts->regmap = regmap;
476 ts->tsc200x_cmd = tsc200x_cmd;
477
478 error = device_property_read_u32(dev, "ti,x-plate-ohms", &x_plate_ohm);
479 ts->x_plate_ohm = error ? TSC200X_DEF_RESISTOR : x_plate_ohm;
480
481 error = device_property_read_u32(dev, "ti,esd-recovery-timeout-ms",
482 &esd_timeout);
483 ts->esd_timeout = error ? 0 : esd_timeout;
484
485 ts->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
486 if (IS_ERR(ts->reset_gpio)) {
487 error = PTR_ERR(ts->reset_gpio);
488 dev_err(dev, "error acquiring reset gpio: %d\n", error);
489 return error;
490 }
491
492 ts->vio = devm_regulator_get(dev, "vio");
493 if (IS_ERR(ts->vio)) {
494 error = PTR_ERR(ts->vio);
495 dev_err(dev, "error acquiring vio regulator: %d", error);
496 return error;
497 }
498
499 mutex_init(&ts->mutex);
500
501 spin_lock_init(&ts->lock);
502 timer_setup(&ts->penup_timer, tsc200x_penup_timer, 0);
503
504 INIT_DELAYED_WORK(&ts->esd_work, tsc200x_esd_work);
505
506 snprintf(ts->phys, sizeof(ts->phys),
507 "%s/input-ts", dev_name(dev));
508
509 if (tsc_id->product == 2004) {
510 input_dev->name = "TSC200X touchscreen";
511 } else {
512 input_dev->name = devm_kasprintf(dev, GFP_KERNEL,
513 "TSC%04d touchscreen",
514 tsc_id->product);
515 if (!input_dev->name)
516 return -ENOMEM;
517 }
518
519 input_dev->phys = ts->phys;
520 input_dev->id = *tsc_id;
521
522 input_dev->open = tsc200x_open;
523 input_dev->close = tsc200x_close;
524
525 input_set_drvdata(input_dev, ts);
526
527 __set_bit(INPUT_PROP_DIRECT, input_dev->propbit);
528 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
529
530 input_set_abs_params(input_dev, ABS_X,
531 0, MAX_12BIT, TSC200X_DEF_X_FUZZ, 0);
532 input_set_abs_params(input_dev, ABS_Y,
533 0, MAX_12BIT, TSC200X_DEF_Y_FUZZ, 0);
534 input_set_abs_params(input_dev, ABS_PRESSURE,
535 0, MAX_12BIT, TSC200X_DEF_P_FUZZ, 0);
536
537 touchscreen_parse_properties(input_dev, false, &ts->prop);
538
539 /* Ensure the touchscreen is off */
540 tsc200x_stop_scan(ts);
541
542 error = devm_request_threaded_irq(dev, irq, NULL,
543 tsc200x_irq_thread,
544 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
545 "tsc200x", ts);
546 if (error) {
547 dev_err(dev, "Failed to request irq, err: %d\n", error);
548 return error;
549 }
550
551 error = regulator_enable(ts->vio);
552 if (error)
553 return error;
554
555 dev_set_drvdata(dev, ts);
556 error = sysfs_create_group(&dev->kobj, &tsc200x_attr_group);
557 if (error) {
558 dev_err(dev,
559 "Failed to create sysfs attributes, err: %d\n", error);
560 goto disable_regulator;
561 }
562
563 error = input_register_device(ts->idev);
564 if (error) {
565 dev_err(dev,
566 "Failed to register input device, err: %d\n", error);
567 goto err_remove_sysfs;
568 }
569
570 irq_set_irq_wake(irq, 1);
571 return 0;
572
573 err_remove_sysfs:
574 sysfs_remove_group(&dev->kobj, &tsc200x_attr_group);
575 disable_regulator:
576 regulator_disable(ts->vio);
577 return error;
578 }
579 EXPORT_SYMBOL_GPL(tsc200x_probe);
580
tsc200x_remove(struct device * dev)581 void tsc200x_remove(struct device *dev)
582 {
583 struct tsc200x *ts = dev_get_drvdata(dev);
584
585 sysfs_remove_group(&dev->kobj, &tsc200x_attr_group);
586
587 regulator_disable(ts->vio);
588 }
589 EXPORT_SYMBOL_GPL(tsc200x_remove);
590
tsc200x_suspend(struct device * dev)591 static int __maybe_unused tsc200x_suspend(struct device *dev)
592 {
593 struct tsc200x *ts = dev_get_drvdata(dev);
594
595 mutex_lock(&ts->mutex);
596
597 if (!ts->suspended && ts->opened)
598 __tsc200x_disable(ts);
599
600 ts->suspended = true;
601
602 mutex_unlock(&ts->mutex);
603
604 return 0;
605 }
606
tsc200x_resume(struct device * dev)607 static int __maybe_unused tsc200x_resume(struct device *dev)
608 {
609 struct tsc200x *ts = dev_get_drvdata(dev);
610
611 mutex_lock(&ts->mutex);
612
613 if (ts->suspended && ts->opened)
614 __tsc200x_enable(ts);
615
616 ts->suspended = false;
617
618 mutex_unlock(&ts->mutex);
619
620 return 0;
621 }
622
623 SIMPLE_DEV_PM_OPS(tsc200x_pm_ops, tsc200x_suspend, tsc200x_resume);
624 EXPORT_SYMBOL_GPL(tsc200x_pm_ops);
625
626 MODULE_AUTHOR("Lauri Leukkunen <lauri.leukkunen@nokia.com>");
627 MODULE_DESCRIPTION("TSC200x Touchscreen Driver Core");
628 MODULE_LICENSE("GPL");
629