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/export.h>
26 #include <linux/input.h>
27 #include <linux/interrupt.h>
28 #include <linux/irq.h>
29 #include <linux/property.h>
30 #include <linux/regmap.h>
31 #include <linux/slab.h>
32 #include <linux/gpio/driver.h>
33
34 #include <linux/input/touchscreen.h>
35 #include <linux/module.h>
36 #include "ad7879.h"
37
38 #define AD7879_REG_ZEROS 0
39 #define AD7879_REG_CTRL1 1
40 #define AD7879_REG_CTRL2 2
41 #define AD7879_REG_CTRL3 3
42 #define AD7879_REG_AUX1HIGH 4
43 #define AD7879_REG_AUX1LOW 5
44 #define AD7879_REG_TEMP1HIGH 6
45 #define AD7879_REG_TEMP1LOW 7
46 #define AD7879_REG_XPLUS 8
47 #define AD7879_REG_YPLUS 9
48 #define AD7879_REG_Z1 10
49 #define AD7879_REG_Z2 11
50 #define AD7879_REG_AUXVBAT 12
51 #define AD7879_REG_TEMP 13
52 #define AD7879_REG_REVID 14
53
54 /* Control REG 1 */
55 #define AD7879_TMR(x) ((x & 0xFF) << 0)
56 #define AD7879_ACQ(x) ((x & 0x3) << 8)
57 #define AD7879_MODE_NOC (0 << 10) /* Do not convert */
58 #define AD7879_MODE_SCC (1 << 10) /* Single channel conversion */
59 #define AD7879_MODE_SEQ0 (2 << 10) /* Sequence 0 in Slave Mode */
60 #define AD7879_MODE_SEQ1 (3 << 10) /* Sequence 1 in Master Mode */
61 #define AD7879_MODE_INT (1 << 15) /* PENIRQ disabled INT enabled */
62
63 /* Control REG 2 */
64 #define AD7879_FCD(x) ((x & 0x3) << 0)
65 #define AD7879_RESET (1 << 4)
66 #define AD7879_MFS(x) ((x & 0x3) << 5)
67 #define AD7879_AVG(x) ((x & 0x3) << 7)
68 #define AD7879_SER (1 << 9) /* non-differential */
69 #define AD7879_DFR (0 << 9) /* differential */
70 #define AD7879_GPIOPOL (1 << 10)
71 #define AD7879_GPIODIR (1 << 11)
72 #define AD7879_GPIO_DATA (1 << 12)
73 #define AD7879_GPIO_EN (1 << 13)
74 #define AD7879_PM(x) ((x & 0x3) << 14)
75 #define AD7879_PM_SHUTDOWN (0)
76 #define AD7879_PM_DYN (1)
77 #define AD7879_PM_FULLON (2)
78
79 /* Control REG 3 */
80 #define AD7879_TEMPMASK_BIT (1<<15)
81 #define AD7879_AUXVBATMASK_BIT (1<<14)
82 #define AD7879_INTMODE_BIT (1<<13)
83 #define AD7879_GPIOALERTMASK_BIT (1<<12)
84 #define AD7879_AUXLOW_BIT (1<<11)
85 #define AD7879_AUXHIGH_BIT (1<<10)
86 #define AD7879_TEMPLOW_BIT (1<<9)
87 #define AD7879_TEMPHIGH_BIT (1<<8)
88 #define AD7879_YPLUS_BIT (1<<7)
89 #define AD7879_XPLUS_BIT (1<<6)
90 #define AD7879_Z1_BIT (1<<5)
91 #define AD7879_Z2_BIT (1<<4)
92 #define AD7879_AUX_BIT (1<<3)
93 #define AD7879_VBAT_BIT (1<<2)
94 #define AD7879_TEMP_BIT (1<<1)
95
96 enum {
97 AD7879_SEQ_YPOS = 0,
98 AD7879_SEQ_XPOS = 1,
99 AD7879_SEQ_Z1 = 2,
100 AD7879_SEQ_Z2 = 3,
101 AD7879_NR_SENSE = 4,
102 };
103
104 #define MAX_12BIT ((1<<12)-1)
105 #define TS_PEN_UP_TIMEOUT msecs_to_jiffies(50)
106
107 struct ad7879 {
108 struct regmap *regmap;
109 struct device *dev;
110 struct input_dev *input;
111 struct timer_list timer;
112 #ifdef CONFIG_GPIOLIB
113 struct gpio_chip gc;
114 struct mutex mutex;
115 #endif
116 unsigned int irq;
117 bool disabled; /* P: input->mutex */
118 bool suspended; /* P: input->mutex */
119 bool swap_xy;
120 u16 conversion_data[AD7879_NR_SENSE];
121 char phys[32];
122 u8 first_conversion_delay;
123 u8 acquisition_time;
124 u8 averaging;
125 u8 pen_down_acc_interval;
126 u8 median;
127 u16 x_plate_ohms;
128 u16 cmd_crtl1;
129 u16 cmd_crtl2;
130 u16 cmd_crtl3;
131 int x;
132 int y;
133 int Rt;
134 };
135
ad7879_read(struct ad7879 * ts,u8 reg)136 static int ad7879_read(struct ad7879 *ts, u8 reg)
137 {
138 unsigned int val;
139 int error;
140
141 error = regmap_read(ts->regmap, reg, &val);
142 if (error) {
143 dev_err(ts->dev, "failed to read register %#02x: %d\n",
144 reg, error);
145 return error;
146 }
147
148 return val;
149 }
150
ad7879_write(struct ad7879 * ts,u8 reg,u16 val)151 static int ad7879_write(struct ad7879 *ts, u8 reg, u16 val)
152 {
153 int error;
154
155 error = regmap_write(ts->regmap, reg, val);
156 if (error) {
157 dev_err(ts->dev,
158 "failed to write %#04x to register %#02x: %d\n",
159 val, reg, error);
160 return error;
161 }
162
163 return 0;
164 }
165
ad7879_report(struct ad7879 * ts)166 static int ad7879_report(struct ad7879 *ts)
167 {
168 struct input_dev *input_dev = ts->input;
169 unsigned Rt;
170 u16 x, y, z1, z2;
171
172 x = ts->conversion_data[AD7879_SEQ_XPOS] & MAX_12BIT;
173 y = ts->conversion_data[AD7879_SEQ_YPOS] & MAX_12BIT;
174 z1 = ts->conversion_data[AD7879_SEQ_Z1] & MAX_12BIT;
175 z2 = ts->conversion_data[AD7879_SEQ_Z2] & MAX_12BIT;
176
177 if (ts->swap_xy)
178 swap(x, y);
179
180 /*
181 * The samples processed here are already preprocessed by the AD7879.
182 * The preprocessing function consists of a median and an averaging
183 * filter. The combination of these two techniques provides a robust
184 * solution, discarding the spurious noise in the signal and keeping
185 * only the data of interest. The size of both filters is
186 * programmable. (dev.platform_data, see linux/platform_data/ad7879.h)
187 * Other user-programmable conversion controls include variable
188 * acquisition time, and first conversion delay. Up to 16 averages can
189 * be taken per conversion.
190 */
191
192 if (likely(x && z1)) {
193 /* compute touch pressure resistance using equation #1 */
194 Rt = (z2 - z1) * x * ts->x_plate_ohms;
195 Rt /= z1;
196 Rt = (Rt + 2047) >> 12;
197
198 /*
199 * Sample found inconsistent, pressure is beyond
200 * the maximum. Don't report it to user space.
201 */
202 if (Rt > input_abs_get_max(input_dev, ABS_PRESSURE))
203 return -EINVAL;
204
205 /*
206 * Note that we delay reporting events by one sample.
207 * This is done to avoid reporting last sample of the
208 * touch sequence, which may be incomplete if finger
209 * leaves the surface before last reading is taken.
210 */
211 if (timer_pending(&ts->timer)) {
212 /* Touch continues */
213 input_report_key(input_dev, BTN_TOUCH, 1);
214 input_report_abs(input_dev, ABS_X, ts->x);
215 input_report_abs(input_dev, ABS_Y, ts->y);
216 input_report_abs(input_dev, ABS_PRESSURE, ts->Rt);
217 input_sync(input_dev);
218 }
219
220 ts->x = x;
221 ts->y = y;
222 ts->Rt = Rt;
223
224 return 0;
225 }
226
227 return -EINVAL;
228 }
229
ad7879_ts_event_release(struct ad7879 * ts)230 static void ad7879_ts_event_release(struct ad7879 *ts)
231 {
232 struct input_dev *input_dev = ts->input;
233
234 input_report_abs(input_dev, ABS_PRESSURE, 0);
235 input_report_key(input_dev, BTN_TOUCH, 0);
236 input_sync(input_dev);
237 }
238
ad7879_timer(struct timer_list * t)239 static void ad7879_timer(struct timer_list *t)
240 {
241 struct ad7879 *ts = timer_container_of(ts, t, timer);
242
243 ad7879_ts_event_release(ts);
244 }
245
ad7879_irq(int irq,void * handle)246 static irqreturn_t ad7879_irq(int irq, void *handle)
247 {
248 struct ad7879 *ts = handle;
249 int error;
250
251 error = regmap_bulk_read(ts->regmap, AD7879_REG_XPLUS,
252 ts->conversion_data, AD7879_NR_SENSE);
253 if (error)
254 dev_err_ratelimited(ts->dev, "failed to read %#02x: %d\n",
255 AD7879_REG_XPLUS, error);
256 else if (!ad7879_report(ts))
257 mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
258
259 return IRQ_HANDLED;
260 }
261
__ad7879_enable(struct ad7879 * ts)262 static void __ad7879_enable(struct ad7879 *ts)
263 {
264 ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
265 ad7879_write(ts, AD7879_REG_CTRL3, ts->cmd_crtl3);
266 ad7879_write(ts, AD7879_REG_CTRL1, ts->cmd_crtl1);
267
268 enable_irq(ts->irq);
269 }
270
__ad7879_disable(struct ad7879 * ts)271 static void __ad7879_disable(struct ad7879 *ts)
272 {
273 u16 reg = (ts->cmd_crtl2 & ~AD7879_PM(-1)) |
274 AD7879_PM(AD7879_PM_SHUTDOWN);
275 disable_irq(ts->irq);
276
277 if (timer_delete_sync(&ts->timer))
278 ad7879_ts_event_release(ts);
279
280 ad7879_write(ts, AD7879_REG_CTRL2, reg);
281 }
282
283
ad7879_open(struct input_dev * input)284 static int ad7879_open(struct input_dev *input)
285 {
286 struct ad7879 *ts = input_get_drvdata(input);
287
288 /* protected by input->mutex */
289 if (!ts->disabled && !ts->suspended)
290 __ad7879_enable(ts);
291
292 return 0;
293 }
294
ad7879_close(struct input_dev * input)295 static void ad7879_close(struct input_dev *input)
296 {
297 struct ad7879 *ts = input_get_drvdata(input);
298
299 /* protected by input->mutex */
300 if (!ts->disabled && !ts->suspended)
301 __ad7879_disable(ts);
302 }
303
ad7879_suspend(struct device * dev)304 static int __maybe_unused ad7879_suspend(struct device *dev)
305 {
306 struct ad7879 *ts = dev_get_drvdata(dev);
307
308 mutex_lock(&ts->input->mutex);
309
310 if (!ts->suspended && !ts->disabled && input_device_enabled(ts->input))
311 __ad7879_disable(ts);
312
313 ts->suspended = true;
314
315 mutex_unlock(&ts->input->mutex);
316
317 return 0;
318 }
319
ad7879_resume(struct device * dev)320 static int __maybe_unused ad7879_resume(struct device *dev)
321 {
322 struct ad7879 *ts = dev_get_drvdata(dev);
323
324 mutex_lock(&ts->input->mutex);
325
326 if (ts->suspended && !ts->disabled && input_device_enabled(ts->input))
327 __ad7879_enable(ts);
328
329 ts->suspended = false;
330
331 mutex_unlock(&ts->input->mutex);
332
333 return 0;
334 }
335
336 SIMPLE_DEV_PM_OPS(ad7879_pm_ops, ad7879_suspend, ad7879_resume);
337 EXPORT_SYMBOL(ad7879_pm_ops);
338
ad7879_toggle(struct ad7879 * ts,bool disable)339 static void ad7879_toggle(struct ad7879 *ts, bool disable)
340 {
341 mutex_lock(&ts->input->mutex);
342
343 if (!ts->suspended && input_device_enabled(ts->input)) {
344
345 if (disable) {
346 if (ts->disabled)
347 __ad7879_enable(ts);
348 } else {
349 if (!ts->disabled)
350 __ad7879_disable(ts);
351 }
352 }
353
354 ts->disabled = disable;
355
356 mutex_unlock(&ts->input->mutex);
357 }
358
ad7879_disable_show(struct device * dev,struct device_attribute * attr,char * buf)359 static ssize_t ad7879_disable_show(struct device *dev,
360 struct device_attribute *attr, char *buf)
361 {
362 struct ad7879 *ts = dev_get_drvdata(dev);
363
364 return sprintf(buf, "%u\n", ts->disabled);
365 }
366
ad7879_disable_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)367 static ssize_t ad7879_disable_store(struct device *dev,
368 struct device_attribute *attr,
369 const char *buf, size_t count)
370 {
371 struct ad7879 *ts = dev_get_drvdata(dev);
372 unsigned int val;
373 int error;
374
375 error = kstrtouint(buf, 10, &val);
376 if (error)
377 return error;
378
379 ad7879_toggle(ts, val);
380
381 return count;
382 }
383
384 static DEVICE_ATTR(disable, 0664, ad7879_disable_show, ad7879_disable_store);
385
386 static struct attribute *ad7879_attributes[] = {
387 &dev_attr_disable.attr,
388 NULL
389 };
390
391 static const struct attribute_group ad7879_attr_group = {
392 .attrs = ad7879_attributes,
393 };
394
395 const struct attribute_group *ad7879_groups[] = {
396 &ad7879_attr_group,
397 NULL
398 };
399 EXPORT_SYMBOL_GPL(ad7879_groups);
400
401 #ifdef CONFIG_GPIOLIB
ad7879_gpio_direction_input(struct gpio_chip * chip,unsigned gpio)402 static int ad7879_gpio_direction_input(struct gpio_chip *chip,
403 unsigned gpio)
404 {
405 struct ad7879 *ts = gpiochip_get_data(chip);
406 int err;
407
408 mutex_lock(&ts->mutex);
409 ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIODIR | AD7879_GPIOPOL;
410 err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
411 mutex_unlock(&ts->mutex);
412
413 return err;
414 }
415
ad7879_gpio_direction_output(struct gpio_chip * chip,unsigned gpio,int level)416 static int ad7879_gpio_direction_output(struct gpio_chip *chip,
417 unsigned gpio, int level)
418 {
419 struct ad7879 *ts = gpiochip_get_data(chip);
420 int err;
421
422 mutex_lock(&ts->mutex);
423 ts->cmd_crtl2 &= ~AD7879_GPIODIR;
424 ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIOPOL;
425 if (level)
426 ts->cmd_crtl2 |= AD7879_GPIO_DATA;
427 else
428 ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
429
430 err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
431 mutex_unlock(&ts->mutex);
432
433 return err;
434 }
435
ad7879_gpio_get_value(struct gpio_chip * chip,unsigned gpio)436 static int ad7879_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
437 {
438 struct ad7879 *ts = gpiochip_get_data(chip);
439 u16 val;
440
441 mutex_lock(&ts->mutex);
442 val = ad7879_read(ts, AD7879_REG_CTRL2);
443 mutex_unlock(&ts->mutex);
444
445 return !!(val & AD7879_GPIO_DATA);
446 }
447
ad7879_gpio_set_value(struct gpio_chip * chip,unsigned int gpio,int value)448 static int ad7879_gpio_set_value(struct gpio_chip *chip, unsigned int gpio,
449 int value)
450 {
451 struct ad7879 *ts = gpiochip_get_data(chip);
452 int ret;
453
454 mutex_lock(&ts->mutex);
455 if (value)
456 ts->cmd_crtl2 |= AD7879_GPIO_DATA;
457 else
458 ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
459
460 ret = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
461 mutex_unlock(&ts->mutex);
462
463 return ret;
464 }
465
ad7879_gpio_add(struct ad7879 * ts)466 static int ad7879_gpio_add(struct ad7879 *ts)
467 {
468 int ret = 0;
469
470 mutex_init(&ts->mutex);
471
472 /* Do not create a chip unless flagged for it */
473 if (!device_property_read_bool(ts->dev, "gpio-controller"))
474 return 0;
475
476 ts->gc.direction_input = ad7879_gpio_direction_input;
477 ts->gc.direction_output = ad7879_gpio_direction_output;
478 ts->gc.get = ad7879_gpio_get_value;
479 ts->gc.set = ad7879_gpio_set_value;
480 ts->gc.can_sleep = 1;
481 ts->gc.base = -1;
482 ts->gc.ngpio = 1;
483 ts->gc.label = "AD7879-GPIO";
484 ts->gc.owner = THIS_MODULE;
485 ts->gc.parent = ts->dev;
486
487 ret = devm_gpiochip_add_data(ts->dev, &ts->gc, ts);
488 if (ret)
489 dev_err(ts->dev, "failed to register gpio %d\n",
490 ts->gc.base);
491
492 return ret;
493 }
494 #else
ad7879_gpio_add(struct ad7879 * ts)495 static int ad7879_gpio_add(struct ad7879 *ts)
496 {
497 return 0;
498 }
499 #endif
500
ad7879_parse_dt(struct device * dev,struct ad7879 * ts)501 static int ad7879_parse_dt(struct device *dev, struct ad7879 *ts)
502 {
503 int err;
504 u32 tmp;
505
506 err = device_property_read_u32(dev, "adi,resistance-plate-x", &tmp);
507 if (err) {
508 dev_err(dev, "failed to get resistance-plate-x property\n");
509 return err;
510 }
511 ts->x_plate_ohms = (u16)tmp;
512
513 device_property_read_u8(dev, "adi,first-conversion-delay",
514 &ts->first_conversion_delay);
515 device_property_read_u8(dev, "adi,acquisition-time",
516 &ts->acquisition_time);
517 device_property_read_u8(dev, "adi,median-filter-size", &ts->median);
518 device_property_read_u8(dev, "adi,averaging", &ts->averaging);
519 device_property_read_u8(dev, "adi,conversion-interval",
520 &ts->pen_down_acc_interval);
521
522 ts->swap_xy = device_property_read_bool(dev, "touchscreen-swapped-x-y");
523
524 return 0;
525 }
526
ad7879_probe(struct device * dev,struct regmap * regmap,int irq,u16 bustype,u8 devid)527 int ad7879_probe(struct device *dev, struct regmap *regmap,
528 int irq, u16 bustype, u8 devid)
529 {
530 struct ad7879 *ts;
531 struct input_dev *input_dev;
532 int err;
533 u16 revid;
534
535 if (irq <= 0) {
536 dev_err(dev, "No IRQ specified\n");
537 return -EINVAL;
538 }
539
540 ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
541 if (!ts)
542 return -ENOMEM;
543
544 err = ad7879_parse_dt(dev, ts);
545 if (err)
546 return err;
547
548 input_dev = devm_input_allocate_device(dev);
549 if (!input_dev) {
550 dev_err(dev, "Failed to allocate input device\n");
551 return -ENOMEM;
552 }
553
554 ts->dev = dev;
555 ts->input = input_dev;
556 ts->irq = irq;
557 ts->regmap = regmap;
558
559 timer_setup(&ts->timer, ad7879_timer, 0);
560 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev));
561
562 input_dev->name = "AD7879 Touchscreen";
563 input_dev->phys = ts->phys;
564 input_dev->dev.parent = dev;
565 input_dev->id.bustype = bustype;
566
567 input_dev->open = ad7879_open;
568 input_dev->close = ad7879_close;
569
570 input_set_drvdata(input_dev, ts);
571
572 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
573
574 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
575 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
576 input_set_capability(input_dev, EV_ABS, ABS_PRESSURE);
577 touchscreen_parse_properties(input_dev, false, NULL);
578 if (!input_abs_get_max(input_dev, ABS_PRESSURE)) {
579 dev_err(dev, "Touchscreen pressure is not specified\n");
580 return -EINVAL;
581 }
582
583 err = ad7879_write(ts, AD7879_REG_CTRL2, AD7879_RESET);
584 if (err < 0) {
585 dev_err(dev, "Failed to write %s\n", input_dev->name);
586 return err;
587 }
588
589 revid = ad7879_read(ts, AD7879_REG_REVID);
590 input_dev->id.product = (revid & 0xff);
591 input_dev->id.version = revid >> 8;
592 if (input_dev->id.product != devid) {
593 dev_err(dev, "Failed to probe %s (%x vs %x)\n",
594 input_dev->name, devid, revid);
595 return -ENODEV;
596 }
597
598 ts->cmd_crtl3 = AD7879_YPLUS_BIT |
599 AD7879_XPLUS_BIT |
600 AD7879_Z2_BIT |
601 AD7879_Z1_BIT |
602 AD7879_TEMPMASK_BIT |
603 AD7879_AUXVBATMASK_BIT |
604 AD7879_GPIOALERTMASK_BIT;
605
606 ts->cmd_crtl2 = AD7879_PM(AD7879_PM_DYN) | AD7879_DFR |
607 AD7879_AVG(ts->averaging) |
608 AD7879_MFS(ts->median) |
609 AD7879_FCD(ts->first_conversion_delay);
610
611 ts->cmd_crtl1 = AD7879_MODE_INT | AD7879_MODE_SEQ1 |
612 AD7879_ACQ(ts->acquisition_time) |
613 AD7879_TMR(ts->pen_down_acc_interval);
614
615 err = devm_request_threaded_irq(dev, ts->irq, NULL, ad7879_irq,
616 IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
617 dev_name(dev), ts);
618 if (err) {
619 dev_err(dev, "Failed to request IRQ: %d\n", err);
620 return err;
621 }
622
623 __ad7879_disable(ts);
624
625 err = ad7879_gpio_add(ts);
626 if (err)
627 return err;
628
629 err = input_register_device(input_dev);
630 if (err)
631 return err;
632
633 dev_set_drvdata(dev, ts);
634
635 return 0;
636 }
637 EXPORT_SYMBOL(ad7879_probe);
638
639 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
640 MODULE_DESCRIPTION("AD7879(-1) touchscreen Driver");
641 MODULE_LICENSE("GPL");
642