1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * AD7879/AD7889 based touchscreen and GPIO driver
4 *
5 * Copyright (C) 2008-2010 Michael Hennerich, Analog Devices Inc.
6 *
7 * History:
8 * Copyright (c) 2005 David Brownell
9 * Copyright (c) 2006 Nokia Corporation
10 * Various changes: Imre Deak <imre.deak@nokia.com>
11 *
12 * Using code from:
13 * - corgi_ts.c
14 * Copyright (C) 2004-2005 Richard Purdie
15 * - omap_ts.[hc], ads7846.h, ts_osk.c
16 * Copyright (C) 2002 MontaVista Software
17 * Copyright (C) 2004 Texas Instruments
18 * Copyright (C) 2005 Dirk Behme
19 * - ad7877.c
20 * Copyright (C) 2006-2008 Analog Devices Inc.
21 */
22
23 #include <linux/device.h>
24 #include <linux/delay.h>
25 #include <linux/input.h>
26 #include <linux/interrupt.h>
27 #include <linux/irq.h>
28 #include <linux/property.h>
29 #include <linux/regmap.h>
30 #include <linux/slab.h>
31 #include <linux/gpio/driver.h>
32
33 #include <linux/input/touchscreen.h>
34 #include <linux/module.h>
35 #include "ad7879.h"
36
37 #define AD7879_REG_ZEROS 0
38 #define AD7879_REG_CTRL1 1
39 #define AD7879_REG_CTRL2 2
40 #define AD7879_REG_CTRL3 3
41 #define AD7879_REG_AUX1HIGH 4
42 #define AD7879_REG_AUX1LOW 5
43 #define AD7879_REG_TEMP1HIGH 6
44 #define AD7879_REG_TEMP1LOW 7
45 #define AD7879_REG_XPLUS 8
46 #define AD7879_REG_YPLUS 9
47 #define AD7879_REG_Z1 10
48 #define AD7879_REG_Z2 11
49 #define AD7879_REG_AUXVBAT 12
50 #define AD7879_REG_TEMP 13
51 #define AD7879_REG_REVID 14
52
53 /* Control REG 1 */
54 #define AD7879_TMR(x) ((x & 0xFF) << 0)
55 #define AD7879_ACQ(x) ((x & 0x3) << 8)
56 #define AD7879_MODE_NOC (0 << 10) /* Do not convert */
57 #define AD7879_MODE_SCC (1 << 10) /* Single channel conversion */
58 #define AD7879_MODE_SEQ0 (2 << 10) /* Sequence 0 in Slave Mode */
59 #define AD7879_MODE_SEQ1 (3 << 10) /* Sequence 1 in Master Mode */
60 #define AD7879_MODE_INT (1 << 15) /* PENIRQ disabled INT enabled */
61
62 /* Control REG 2 */
63 #define AD7879_FCD(x) ((x & 0x3) << 0)
64 #define AD7879_RESET (1 << 4)
65 #define AD7879_MFS(x) ((x & 0x3) << 5)
66 #define AD7879_AVG(x) ((x & 0x3) << 7)
67 #define AD7879_SER (1 << 9) /* non-differential */
68 #define AD7879_DFR (0 << 9) /* differential */
69 #define AD7879_GPIOPOL (1 << 10)
70 #define AD7879_GPIODIR (1 << 11)
71 #define AD7879_GPIO_DATA (1 << 12)
72 #define AD7879_GPIO_EN (1 << 13)
73 #define AD7879_PM(x) ((x & 0x3) << 14)
74 #define AD7879_PM_SHUTDOWN (0)
75 #define AD7879_PM_DYN (1)
76 #define AD7879_PM_FULLON (2)
77
78 /* Control REG 3 */
79 #define AD7879_TEMPMASK_BIT (1<<15)
80 #define AD7879_AUXVBATMASK_BIT (1<<14)
81 #define AD7879_INTMODE_BIT (1<<13)
82 #define AD7879_GPIOALERTMASK_BIT (1<<12)
83 #define AD7879_AUXLOW_BIT (1<<11)
84 #define AD7879_AUXHIGH_BIT (1<<10)
85 #define AD7879_TEMPLOW_BIT (1<<9)
86 #define AD7879_TEMPHIGH_BIT (1<<8)
87 #define AD7879_YPLUS_BIT (1<<7)
88 #define AD7879_XPLUS_BIT (1<<6)
89 #define AD7879_Z1_BIT (1<<5)
90 #define AD7879_Z2_BIT (1<<4)
91 #define AD7879_AUX_BIT (1<<3)
92 #define AD7879_VBAT_BIT (1<<2)
93 #define AD7879_TEMP_BIT (1<<1)
94
95 enum {
96 AD7879_SEQ_YPOS = 0,
97 AD7879_SEQ_XPOS = 1,
98 AD7879_SEQ_Z1 = 2,
99 AD7879_SEQ_Z2 = 3,
100 AD7879_NR_SENSE = 4,
101 };
102
103 #define MAX_12BIT ((1<<12)-1)
104 #define TS_PEN_UP_TIMEOUT msecs_to_jiffies(50)
105
106 struct ad7879 {
107 struct regmap *regmap;
108 struct device *dev;
109 struct input_dev *input;
110 struct timer_list timer;
111 #ifdef CONFIG_GPIOLIB
112 struct gpio_chip gc;
113 struct mutex mutex;
114 #endif
115 unsigned int irq;
116 bool disabled; /* P: input->mutex */
117 bool suspended; /* P: input->mutex */
118 bool swap_xy;
119 u16 conversion_data[AD7879_NR_SENSE];
120 char phys[32];
121 u8 first_conversion_delay;
122 u8 acquisition_time;
123 u8 averaging;
124 u8 pen_down_acc_interval;
125 u8 median;
126 u16 x_plate_ohms;
127 u16 cmd_crtl1;
128 u16 cmd_crtl2;
129 u16 cmd_crtl3;
130 int x;
131 int y;
132 int Rt;
133 };
134
ad7879_read(struct ad7879 * ts,u8 reg)135 static int ad7879_read(struct ad7879 *ts, u8 reg)
136 {
137 unsigned int val;
138 int error;
139
140 error = regmap_read(ts->regmap, reg, &val);
141 if (error) {
142 dev_err(ts->dev, "failed to read register %#02x: %d\n",
143 reg, error);
144 return error;
145 }
146
147 return val;
148 }
149
ad7879_write(struct ad7879 * ts,u8 reg,u16 val)150 static int ad7879_write(struct ad7879 *ts, u8 reg, u16 val)
151 {
152 int error;
153
154 error = regmap_write(ts->regmap, reg, val);
155 if (error) {
156 dev_err(ts->dev,
157 "failed to write %#04x to register %#02x: %d\n",
158 val, reg, error);
159 return error;
160 }
161
162 return 0;
163 }
164
ad7879_report(struct ad7879 * ts)165 static int ad7879_report(struct ad7879 *ts)
166 {
167 struct input_dev *input_dev = ts->input;
168 unsigned Rt;
169 u16 x, y, z1, z2;
170
171 x = ts->conversion_data[AD7879_SEQ_XPOS] & MAX_12BIT;
172 y = ts->conversion_data[AD7879_SEQ_YPOS] & MAX_12BIT;
173 z1 = ts->conversion_data[AD7879_SEQ_Z1] & MAX_12BIT;
174 z2 = ts->conversion_data[AD7879_SEQ_Z2] & MAX_12BIT;
175
176 if (ts->swap_xy)
177 swap(x, y);
178
179 /*
180 * The samples processed here are already preprocessed by the AD7879.
181 * The preprocessing function consists of a median and an averaging
182 * filter. The combination of these two techniques provides a robust
183 * solution, discarding the spurious noise in the signal and keeping
184 * only the data of interest. The size of both filters is
185 * programmable. (dev.platform_data, see linux/platform_data/ad7879.h)
186 * Other user-programmable conversion controls include variable
187 * acquisition time, and first conversion delay. Up to 16 averages can
188 * be taken per conversion.
189 */
190
191 if (likely(x && z1)) {
192 /* compute touch pressure resistance using equation #1 */
193 Rt = (z2 - z1) * x * ts->x_plate_ohms;
194 Rt /= z1;
195 Rt = (Rt + 2047) >> 12;
196
197 /*
198 * Sample found inconsistent, pressure is beyond
199 * the maximum. Don't report it to user space.
200 */
201 if (Rt > input_abs_get_max(input_dev, ABS_PRESSURE))
202 return -EINVAL;
203
204 /*
205 * Note that we delay reporting events by one sample.
206 * This is done to avoid reporting last sample of the
207 * touch sequence, which may be incomplete if finger
208 * leaves the surface before last reading is taken.
209 */
210 if (timer_pending(&ts->timer)) {
211 /* Touch continues */
212 input_report_key(input_dev, BTN_TOUCH, 1);
213 input_report_abs(input_dev, ABS_X, ts->x);
214 input_report_abs(input_dev, ABS_Y, ts->y);
215 input_report_abs(input_dev, ABS_PRESSURE, ts->Rt);
216 input_sync(input_dev);
217 }
218
219 ts->x = x;
220 ts->y = y;
221 ts->Rt = Rt;
222
223 return 0;
224 }
225
226 return -EINVAL;
227 }
228
ad7879_ts_event_release(struct ad7879 * ts)229 static void ad7879_ts_event_release(struct ad7879 *ts)
230 {
231 struct input_dev *input_dev = ts->input;
232
233 input_report_abs(input_dev, ABS_PRESSURE, 0);
234 input_report_key(input_dev, BTN_TOUCH, 0);
235 input_sync(input_dev);
236 }
237
ad7879_timer(struct timer_list * t)238 static void ad7879_timer(struct timer_list *t)
239 {
240 struct ad7879 *ts = from_timer(ts, t, timer);
241
242 ad7879_ts_event_release(ts);
243 }
244
ad7879_irq(int irq,void * handle)245 static irqreturn_t ad7879_irq(int irq, void *handle)
246 {
247 struct ad7879 *ts = handle;
248 int error;
249
250 error = regmap_bulk_read(ts->regmap, AD7879_REG_XPLUS,
251 ts->conversion_data, AD7879_NR_SENSE);
252 if (error)
253 dev_err_ratelimited(ts->dev, "failed to read %#02x: %d\n",
254 AD7879_REG_XPLUS, error);
255 else if (!ad7879_report(ts))
256 mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
257
258 return IRQ_HANDLED;
259 }
260
__ad7879_enable(struct ad7879 * ts)261 static void __ad7879_enable(struct ad7879 *ts)
262 {
263 ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
264 ad7879_write(ts, AD7879_REG_CTRL3, ts->cmd_crtl3);
265 ad7879_write(ts, AD7879_REG_CTRL1, ts->cmd_crtl1);
266
267 enable_irq(ts->irq);
268 }
269
__ad7879_disable(struct ad7879 * ts)270 static void __ad7879_disable(struct ad7879 *ts)
271 {
272 u16 reg = (ts->cmd_crtl2 & ~AD7879_PM(-1)) |
273 AD7879_PM(AD7879_PM_SHUTDOWN);
274 disable_irq(ts->irq);
275
276 if (del_timer_sync(&ts->timer))
277 ad7879_ts_event_release(ts);
278
279 ad7879_write(ts, AD7879_REG_CTRL2, reg);
280 }
281
282
ad7879_open(struct input_dev * input)283 static int ad7879_open(struct input_dev *input)
284 {
285 struct ad7879 *ts = input_get_drvdata(input);
286
287 /* protected by input->mutex */
288 if (!ts->disabled && !ts->suspended)
289 __ad7879_enable(ts);
290
291 return 0;
292 }
293
ad7879_close(struct input_dev * input)294 static void ad7879_close(struct input_dev *input)
295 {
296 struct ad7879 *ts = input_get_drvdata(input);
297
298 /* protected by input->mutex */
299 if (!ts->disabled && !ts->suspended)
300 __ad7879_disable(ts);
301 }
302
ad7879_suspend(struct device * dev)303 static int __maybe_unused ad7879_suspend(struct device *dev)
304 {
305 struct ad7879 *ts = dev_get_drvdata(dev);
306
307 mutex_lock(&ts->input->mutex);
308
309 if (!ts->suspended && !ts->disabled && input_device_enabled(ts->input))
310 __ad7879_disable(ts);
311
312 ts->suspended = true;
313
314 mutex_unlock(&ts->input->mutex);
315
316 return 0;
317 }
318
ad7879_resume(struct device * dev)319 static int __maybe_unused ad7879_resume(struct device *dev)
320 {
321 struct ad7879 *ts = dev_get_drvdata(dev);
322
323 mutex_lock(&ts->input->mutex);
324
325 if (ts->suspended && !ts->disabled && input_device_enabled(ts->input))
326 __ad7879_enable(ts);
327
328 ts->suspended = false;
329
330 mutex_unlock(&ts->input->mutex);
331
332 return 0;
333 }
334
335 SIMPLE_DEV_PM_OPS(ad7879_pm_ops, ad7879_suspend, ad7879_resume);
336 EXPORT_SYMBOL(ad7879_pm_ops);
337
ad7879_toggle(struct ad7879 * ts,bool disable)338 static void ad7879_toggle(struct ad7879 *ts, bool disable)
339 {
340 mutex_lock(&ts->input->mutex);
341
342 if (!ts->suspended && input_device_enabled(ts->input)) {
343
344 if (disable) {
345 if (ts->disabled)
346 __ad7879_enable(ts);
347 } else {
348 if (!ts->disabled)
349 __ad7879_disable(ts);
350 }
351 }
352
353 ts->disabled = disable;
354
355 mutex_unlock(&ts->input->mutex);
356 }
357
ad7879_disable_show(struct device * dev,struct device_attribute * attr,char * buf)358 static ssize_t ad7879_disable_show(struct device *dev,
359 struct device_attribute *attr, char *buf)
360 {
361 struct ad7879 *ts = dev_get_drvdata(dev);
362
363 return sprintf(buf, "%u\n", ts->disabled);
364 }
365
ad7879_disable_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)366 static ssize_t ad7879_disable_store(struct device *dev,
367 struct device_attribute *attr,
368 const char *buf, size_t count)
369 {
370 struct ad7879 *ts = dev_get_drvdata(dev);
371 unsigned int val;
372 int error;
373
374 error = kstrtouint(buf, 10, &val);
375 if (error)
376 return error;
377
378 ad7879_toggle(ts, val);
379
380 return count;
381 }
382
383 static DEVICE_ATTR(disable, 0664, ad7879_disable_show, ad7879_disable_store);
384
385 static struct attribute *ad7879_attributes[] = {
386 &dev_attr_disable.attr,
387 NULL
388 };
389
390 static const struct attribute_group ad7879_attr_group = {
391 .attrs = ad7879_attributes,
392 };
393
394 #ifdef CONFIG_GPIOLIB
ad7879_gpio_direction_input(struct gpio_chip * chip,unsigned gpio)395 static int ad7879_gpio_direction_input(struct gpio_chip *chip,
396 unsigned gpio)
397 {
398 struct ad7879 *ts = gpiochip_get_data(chip);
399 int err;
400
401 mutex_lock(&ts->mutex);
402 ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIODIR | AD7879_GPIOPOL;
403 err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
404 mutex_unlock(&ts->mutex);
405
406 return err;
407 }
408
ad7879_gpio_direction_output(struct gpio_chip * chip,unsigned gpio,int level)409 static int ad7879_gpio_direction_output(struct gpio_chip *chip,
410 unsigned gpio, int level)
411 {
412 struct ad7879 *ts = gpiochip_get_data(chip);
413 int err;
414
415 mutex_lock(&ts->mutex);
416 ts->cmd_crtl2 &= ~AD7879_GPIODIR;
417 ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIOPOL;
418 if (level)
419 ts->cmd_crtl2 |= AD7879_GPIO_DATA;
420 else
421 ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
422
423 err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
424 mutex_unlock(&ts->mutex);
425
426 return err;
427 }
428
ad7879_gpio_get_value(struct gpio_chip * chip,unsigned gpio)429 static int ad7879_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
430 {
431 struct ad7879 *ts = gpiochip_get_data(chip);
432 u16 val;
433
434 mutex_lock(&ts->mutex);
435 val = ad7879_read(ts, AD7879_REG_CTRL2);
436 mutex_unlock(&ts->mutex);
437
438 return !!(val & AD7879_GPIO_DATA);
439 }
440
ad7879_gpio_set_value(struct gpio_chip * chip,unsigned gpio,int value)441 static void ad7879_gpio_set_value(struct gpio_chip *chip,
442 unsigned gpio, int value)
443 {
444 struct ad7879 *ts = gpiochip_get_data(chip);
445
446 mutex_lock(&ts->mutex);
447 if (value)
448 ts->cmd_crtl2 |= AD7879_GPIO_DATA;
449 else
450 ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
451
452 ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
453 mutex_unlock(&ts->mutex);
454 }
455
ad7879_gpio_add(struct ad7879 * ts)456 static int ad7879_gpio_add(struct ad7879 *ts)
457 {
458 int ret = 0;
459
460 mutex_init(&ts->mutex);
461
462 /* Do not create a chip unless flagged for it */
463 if (!device_property_read_bool(ts->dev, "gpio-controller"))
464 return 0;
465
466 ts->gc.direction_input = ad7879_gpio_direction_input;
467 ts->gc.direction_output = ad7879_gpio_direction_output;
468 ts->gc.get = ad7879_gpio_get_value;
469 ts->gc.set = ad7879_gpio_set_value;
470 ts->gc.can_sleep = 1;
471 ts->gc.base = -1;
472 ts->gc.ngpio = 1;
473 ts->gc.label = "AD7879-GPIO";
474 ts->gc.owner = THIS_MODULE;
475 ts->gc.parent = ts->dev;
476
477 ret = devm_gpiochip_add_data(ts->dev, &ts->gc, ts);
478 if (ret)
479 dev_err(ts->dev, "failed to register gpio %d\n",
480 ts->gc.base);
481
482 return ret;
483 }
484 #else
ad7879_gpio_add(struct ad7879 * ts)485 static int ad7879_gpio_add(struct ad7879 *ts)
486 {
487 return 0;
488 }
489 #endif
490
ad7879_parse_dt(struct device * dev,struct ad7879 * ts)491 static int ad7879_parse_dt(struct device *dev, struct ad7879 *ts)
492 {
493 int err;
494 u32 tmp;
495
496 err = device_property_read_u32(dev, "adi,resistance-plate-x", &tmp);
497 if (err) {
498 dev_err(dev, "failed to get resistance-plate-x property\n");
499 return err;
500 }
501 ts->x_plate_ohms = (u16)tmp;
502
503 device_property_read_u8(dev, "adi,first-conversion-delay",
504 &ts->first_conversion_delay);
505 device_property_read_u8(dev, "adi,acquisition-time",
506 &ts->acquisition_time);
507 device_property_read_u8(dev, "adi,median-filter-size", &ts->median);
508 device_property_read_u8(dev, "adi,averaging", &ts->averaging);
509 device_property_read_u8(dev, "adi,conversion-interval",
510 &ts->pen_down_acc_interval);
511
512 ts->swap_xy = device_property_read_bool(dev, "touchscreen-swapped-x-y");
513
514 return 0;
515 }
516
ad7879_probe(struct device * dev,struct regmap * regmap,int irq,u16 bustype,u8 devid)517 int ad7879_probe(struct device *dev, struct regmap *regmap,
518 int irq, u16 bustype, u8 devid)
519 {
520 struct ad7879 *ts;
521 struct input_dev *input_dev;
522 int err;
523 u16 revid;
524
525 if (irq <= 0) {
526 dev_err(dev, "No IRQ specified\n");
527 return -EINVAL;
528 }
529
530 ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
531 if (!ts)
532 return -ENOMEM;
533
534 err = ad7879_parse_dt(dev, ts);
535 if (err)
536 return err;
537
538 input_dev = devm_input_allocate_device(dev);
539 if (!input_dev) {
540 dev_err(dev, "Failed to allocate input device\n");
541 return -ENOMEM;
542 }
543
544 ts->dev = dev;
545 ts->input = input_dev;
546 ts->irq = irq;
547 ts->regmap = regmap;
548
549 timer_setup(&ts->timer, ad7879_timer, 0);
550 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev));
551
552 input_dev->name = "AD7879 Touchscreen";
553 input_dev->phys = ts->phys;
554 input_dev->dev.parent = dev;
555 input_dev->id.bustype = bustype;
556
557 input_dev->open = ad7879_open;
558 input_dev->close = ad7879_close;
559
560 input_set_drvdata(input_dev, ts);
561
562 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
563
564 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
565 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
566 input_set_capability(input_dev, EV_ABS, ABS_PRESSURE);
567 touchscreen_parse_properties(input_dev, false, NULL);
568 if (!input_abs_get_max(input_dev, ABS_PRESSURE)) {
569 dev_err(dev, "Touchscreen pressure is not specified\n");
570 return -EINVAL;
571 }
572
573 err = ad7879_write(ts, AD7879_REG_CTRL2, AD7879_RESET);
574 if (err < 0) {
575 dev_err(dev, "Failed to write %s\n", input_dev->name);
576 return err;
577 }
578
579 revid = ad7879_read(ts, AD7879_REG_REVID);
580 input_dev->id.product = (revid & 0xff);
581 input_dev->id.version = revid >> 8;
582 if (input_dev->id.product != devid) {
583 dev_err(dev, "Failed to probe %s (%x vs %x)\n",
584 input_dev->name, devid, revid);
585 return -ENODEV;
586 }
587
588 ts->cmd_crtl3 = AD7879_YPLUS_BIT |
589 AD7879_XPLUS_BIT |
590 AD7879_Z2_BIT |
591 AD7879_Z1_BIT |
592 AD7879_TEMPMASK_BIT |
593 AD7879_AUXVBATMASK_BIT |
594 AD7879_GPIOALERTMASK_BIT;
595
596 ts->cmd_crtl2 = AD7879_PM(AD7879_PM_DYN) | AD7879_DFR |
597 AD7879_AVG(ts->averaging) |
598 AD7879_MFS(ts->median) |
599 AD7879_FCD(ts->first_conversion_delay);
600
601 ts->cmd_crtl1 = AD7879_MODE_INT | AD7879_MODE_SEQ1 |
602 AD7879_ACQ(ts->acquisition_time) |
603 AD7879_TMR(ts->pen_down_acc_interval);
604
605 err = devm_request_threaded_irq(dev, ts->irq, NULL, ad7879_irq,
606 IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
607 dev_name(dev), ts);
608 if (err) {
609 dev_err(dev, "Failed to request IRQ: %d\n", err);
610 return err;
611 }
612
613 __ad7879_disable(ts);
614
615 err = devm_device_add_group(dev, &ad7879_attr_group);
616 if (err)
617 return err;
618
619 err = ad7879_gpio_add(ts);
620 if (err)
621 return err;
622
623 err = input_register_device(input_dev);
624 if (err)
625 return err;
626
627 dev_set_drvdata(dev, ts);
628
629 return 0;
630 }
631 EXPORT_SYMBOL(ad7879_probe);
632
633 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
634 MODULE_DESCRIPTION("AD7879(-1) touchscreen Driver");
635 MODULE_LICENSE("GPL");
636