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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
95enum {
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
106struct 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
135static 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
150static 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
165static 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
229static 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
238static 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
245static 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
261static 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
270static 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
283static 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
294static 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
303static 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
319static 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
335SIMPLE_DEV_PM_OPS(ad7879_pm_ops, ad7879_suspend, ad7879_resume);
336EXPORT_SYMBOL(ad7879_pm_ops);
337
338static 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
358static 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
366static 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
383static DEVICE_ATTR(disable, 0664, ad7879_disable_show, ad7879_disable_store);
384
385static struct attribute *ad7879_attributes[] = {
386 &dev_attr_disable.attr,
387 NULL
388};
389
390static const struct attribute_group ad7879_attr_group = {
391 .attrs = ad7879_attributes,
392};
393
394const struct attribute_group *ad7879_groups[] = {
395 &ad7879_attr_group,
396 NULL
397};
398EXPORT_SYMBOL_GPL(ad7879_groups);
399
400#ifdef CONFIG_GPIOLIB
401static int ad7879_gpio_direction_input(struct gpio_chip *chip,
402 unsigned gpio)
403{
404 struct ad7879 *ts = gpiochip_get_data(chip);
405 int err;
406
407 mutex_lock(&ts->mutex);
408 ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIODIR | AD7879_GPIOPOL;
409 err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
410 mutex_unlock(&ts->mutex);
411
412 return err;
413}
414
415static int ad7879_gpio_direction_output(struct gpio_chip *chip,
416 unsigned gpio, int level)
417{
418 struct ad7879 *ts = gpiochip_get_data(chip);
419 int err;
420
421 mutex_lock(&ts->mutex);
422 ts->cmd_crtl2 &= ~AD7879_GPIODIR;
423 ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIOPOL;
424 if (level)
425 ts->cmd_crtl2 |= AD7879_GPIO_DATA;
426 else
427 ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
428
429 err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
430 mutex_unlock(&ts->mutex);
431
432 return err;
433}
434
435static int ad7879_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
436{
437 struct ad7879 *ts = gpiochip_get_data(chip);
438 u16 val;
439
440 mutex_lock(&ts->mutex);
441 val = ad7879_read(ts, AD7879_REG_CTRL2);
442 mutex_unlock(&ts->mutex);
443
444 return !!(val & AD7879_GPIO_DATA);
445}
446
447static void ad7879_gpio_set_value(struct gpio_chip *chip,
448 unsigned gpio, int value)
449{
450 struct ad7879 *ts = gpiochip_get_data(chip);
451
452 mutex_lock(&ts->mutex);
453 if (value)
454 ts->cmd_crtl2 |= AD7879_GPIO_DATA;
455 else
456 ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
457
458 ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
459 mutex_unlock(&ts->mutex);
460}
461
462static int ad7879_gpio_add(struct ad7879 *ts)
463{
464 int ret = 0;
465
466 mutex_init(&ts->mutex);
467
468 /* Do not create a chip unless flagged for it */
469 if (!device_property_read_bool(ts->dev, "gpio-controller"))
470 return 0;
471
472 ts->gc.direction_input = ad7879_gpio_direction_input;
473 ts->gc.direction_output = ad7879_gpio_direction_output;
474 ts->gc.get = ad7879_gpio_get_value;
475 ts->gc.set = ad7879_gpio_set_value;
476 ts->gc.can_sleep = 1;
477 ts->gc.base = -1;
478 ts->gc.ngpio = 1;
479 ts->gc.label = "AD7879-GPIO";
480 ts->gc.owner = THIS_MODULE;
481 ts->gc.parent = ts->dev;
482
483 ret = devm_gpiochip_add_data(ts->dev, &ts->gc, ts);
484 if (ret)
485 dev_err(ts->dev, "failed to register gpio %d\n",
486 ts->gc.base);
487
488 return ret;
489}
490#else
491static int ad7879_gpio_add(struct ad7879 *ts)
492{
493 return 0;
494}
495#endif
496
497static int ad7879_parse_dt(struct device *dev, struct ad7879 *ts)
498{
499 int err;
500 u32 tmp;
501
502 err = device_property_read_u32(dev, "adi,resistance-plate-x", &tmp);
503 if (err) {
504 dev_err(dev, "failed to get resistance-plate-x property\n");
505 return err;
506 }
507 ts->x_plate_ohms = (u16)tmp;
508
509 device_property_read_u8(dev, "adi,first-conversion-delay",
510 &ts->first_conversion_delay);
511 device_property_read_u8(dev, "adi,acquisition-time",
512 &ts->acquisition_time);
513 device_property_read_u8(dev, "adi,median-filter-size", &ts->median);
514 device_property_read_u8(dev, "adi,averaging", &ts->averaging);
515 device_property_read_u8(dev, "adi,conversion-interval",
516 &ts->pen_down_acc_interval);
517
518 ts->swap_xy = device_property_read_bool(dev, "touchscreen-swapped-x-y");
519
520 return 0;
521}
522
523int ad7879_probe(struct device *dev, struct regmap *regmap,
524 int irq, u16 bustype, u8 devid)
525{
526 struct ad7879 *ts;
527 struct input_dev *input_dev;
528 int err;
529 u16 revid;
530
531 if (irq <= 0) {
532 dev_err(dev, "No IRQ specified\n");
533 return -EINVAL;
534 }
535
536 ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
537 if (!ts)
538 return -ENOMEM;
539
540 err = ad7879_parse_dt(dev, ts);
541 if (err)
542 return err;
543
544 input_dev = devm_input_allocate_device(dev);
545 if (!input_dev) {
546 dev_err(dev, "Failed to allocate input device\n");
547 return -ENOMEM;
548 }
549
550 ts->dev = dev;
551 ts->input = input_dev;
552 ts->irq = irq;
553 ts->regmap = regmap;
554
555 timer_setup(&ts->timer, ad7879_timer, 0);
556 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev));
557
558 input_dev->name = "AD7879 Touchscreen";
559 input_dev->phys = ts->phys;
560 input_dev->dev.parent = dev;
561 input_dev->id.bustype = bustype;
562
563 input_dev->open = ad7879_open;
564 input_dev->close = ad7879_close;
565
566 input_set_drvdata(input_dev, ts);
567
568 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
569
570 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
571 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
572 input_set_capability(input_dev, EV_ABS, ABS_PRESSURE);
573 touchscreen_parse_properties(input_dev, false, NULL);
574 if (!input_abs_get_max(input_dev, ABS_PRESSURE)) {
575 dev_err(dev, "Touchscreen pressure is not specified\n");
576 return -EINVAL;
577 }
578
579 err = ad7879_write(ts, AD7879_REG_CTRL2, AD7879_RESET);
580 if (err < 0) {
581 dev_err(dev, "Failed to write %s\n", input_dev->name);
582 return err;
583 }
584
585 revid = ad7879_read(ts, AD7879_REG_REVID);
586 input_dev->id.product = (revid & 0xff);
587 input_dev->id.version = revid >> 8;
588 if (input_dev->id.product != devid) {
589 dev_err(dev, "Failed to probe %s (%x vs %x)\n",
590 input_dev->name, devid, revid);
591 return -ENODEV;
592 }
593
594 ts->cmd_crtl3 = AD7879_YPLUS_BIT |
595 AD7879_XPLUS_BIT |
596 AD7879_Z2_BIT |
597 AD7879_Z1_BIT |
598 AD7879_TEMPMASK_BIT |
599 AD7879_AUXVBATMASK_BIT |
600 AD7879_GPIOALERTMASK_BIT;
601
602 ts->cmd_crtl2 = AD7879_PM(AD7879_PM_DYN) | AD7879_DFR |
603 AD7879_AVG(ts->averaging) |
604 AD7879_MFS(ts->median) |
605 AD7879_FCD(ts->first_conversion_delay);
606
607 ts->cmd_crtl1 = AD7879_MODE_INT | AD7879_MODE_SEQ1 |
608 AD7879_ACQ(ts->acquisition_time) |
609 AD7879_TMR(ts->pen_down_acc_interval);
610
611 err = devm_request_threaded_irq(dev, ts->irq, NULL, ad7879_irq,
612 IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
613 dev_name(dev), ts);
614 if (err) {
615 dev_err(dev, "Failed to request IRQ: %d\n", err);
616 return err;
617 }
618
619 __ad7879_disable(ts);
620
621 err = ad7879_gpio_add(ts);
622 if (err)
623 return err;
624
625 err = input_register_device(input_dev);
626 if (err)
627 return err;
628
629 dev_set_drvdata(dev, ts);
630
631 return 0;
632}
633EXPORT_SYMBOL(ad7879_probe);
634
635MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
636MODULE_DESCRIPTION("AD7879(-1) touchscreen Driver");
637MODULE_LICENSE("GPL");
1/*
2 * AD7879/AD7889 based touchscreen and GPIO driver
3 *
4 * Copyright (C) 2008-2010 Michael Hennerich, Analog Devices Inc.
5 *
6 * Licensed under the GPL-2 or later.
7 *
8 * History:
9 * Copyright (c) 2005 David Brownell
10 * Copyright (c) 2006 Nokia Corporation
11 * Various changes: Imre Deak <imre.deak@nokia.com>
12 *
13 * Using code from:
14 * - corgi_ts.c
15 * Copyright (C) 2004-2005 Richard Purdie
16 * - omap_ts.[hc], ads7846.h, ts_osk.c
17 * Copyright (C) 2002 MontaVista Software
18 * Copyright (C) 2004 Texas Instruments
19 * Copyright (C) 2005 Dirk Behme
20 * - ad7877.c
21 * Copyright (C) 2006-2008 Analog Devices Inc.
22 */
23
24#include <linux/device.h>
25#include <linux/delay.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.h>
33
34#include <linux/input/touchscreen.h>
35#include <linux/platform_data/ad7879.h>
36#include <linux/module.h>
37#include "ad7879.h"
38
39#define AD7879_REG_ZEROS 0
40#define AD7879_REG_CTRL1 1
41#define AD7879_REG_CTRL2 2
42#define AD7879_REG_CTRL3 3
43#define AD7879_REG_AUX1HIGH 4
44#define AD7879_REG_AUX1LOW 5
45#define AD7879_REG_TEMP1HIGH 6
46#define AD7879_REG_TEMP1LOW 7
47#define AD7879_REG_XPLUS 8
48#define AD7879_REG_YPLUS 9
49#define AD7879_REG_Z1 10
50#define AD7879_REG_Z2 11
51#define AD7879_REG_AUXVBAT 12
52#define AD7879_REG_TEMP 13
53#define AD7879_REG_REVID 14
54
55/* Control REG 1 */
56#define AD7879_TMR(x) ((x & 0xFF) << 0)
57#define AD7879_ACQ(x) ((x & 0x3) << 8)
58#define AD7879_MODE_NOC (0 << 10) /* Do not convert */
59#define AD7879_MODE_SCC (1 << 10) /* Single channel conversion */
60#define AD7879_MODE_SEQ0 (2 << 10) /* Sequence 0 in Slave Mode */
61#define AD7879_MODE_SEQ1 (3 << 10) /* Sequence 1 in Master Mode */
62#define AD7879_MODE_INT (1 << 15) /* PENIRQ disabled INT enabled */
63
64/* Control REG 2 */
65#define AD7879_FCD(x) ((x & 0x3) << 0)
66#define AD7879_RESET (1 << 4)
67#define AD7879_MFS(x) ((x & 0x3) << 5)
68#define AD7879_AVG(x) ((x & 0x3) << 7)
69#define AD7879_SER (1 << 9) /* non-differential */
70#define AD7879_DFR (0 << 9) /* differential */
71#define AD7879_GPIOPOL (1 << 10)
72#define AD7879_GPIODIR (1 << 11)
73#define AD7879_GPIO_DATA (1 << 12)
74#define AD7879_GPIO_EN (1 << 13)
75#define AD7879_PM(x) ((x & 0x3) << 14)
76#define AD7879_PM_SHUTDOWN (0)
77#define AD7879_PM_DYN (1)
78#define AD7879_PM_FULLON (2)
79
80/* Control REG 3 */
81#define AD7879_TEMPMASK_BIT (1<<15)
82#define AD7879_AUXVBATMASK_BIT (1<<14)
83#define AD7879_INTMODE_BIT (1<<13)
84#define AD7879_GPIOALERTMASK_BIT (1<<12)
85#define AD7879_AUXLOW_BIT (1<<11)
86#define AD7879_AUXHIGH_BIT (1<<10)
87#define AD7879_TEMPLOW_BIT (1<<9)
88#define AD7879_TEMPHIGH_BIT (1<<8)
89#define AD7879_YPLUS_BIT (1<<7)
90#define AD7879_XPLUS_BIT (1<<6)
91#define AD7879_Z1_BIT (1<<5)
92#define AD7879_Z2_BIT (1<<4)
93#define AD7879_AUX_BIT (1<<3)
94#define AD7879_VBAT_BIT (1<<2)
95#define AD7879_TEMP_BIT (1<<1)
96
97enum {
98 AD7879_SEQ_YPOS = 0,
99 AD7879_SEQ_XPOS = 1,
100 AD7879_SEQ_Z1 = 2,
101 AD7879_SEQ_Z2 = 3,
102 AD7879_NR_SENSE = 4,
103};
104
105#define MAX_12BIT ((1<<12)-1)
106#define TS_PEN_UP_TIMEOUT msecs_to_jiffies(50)
107
108struct ad7879 {
109 struct regmap *regmap;
110 struct device *dev;
111 struct input_dev *input;
112 struct timer_list timer;
113#ifdef CONFIG_GPIOLIB
114 struct gpio_chip gc;
115 struct mutex mutex;
116#endif
117 unsigned int irq;
118 bool disabled; /* P: input->mutex */
119 bool suspended; /* P: input->mutex */
120 bool swap_xy;
121 u16 conversion_data[AD7879_NR_SENSE];
122 char phys[32];
123 u8 first_conversion_delay;
124 u8 acquisition_time;
125 u8 averaging;
126 u8 pen_down_acc_interval;
127 u8 median;
128 u16 x_plate_ohms;
129 u16 cmd_crtl1;
130 u16 cmd_crtl2;
131 u16 cmd_crtl3;
132 int x;
133 int y;
134 int Rt;
135};
136
137static int ad7879_read(struct ad7879 *ts, u8 reg)
138{
139 unsigned int val;
140 int error;
141
142 error = regmap_read(ts->regmap, reg, &val);
143 if (error) {
144 dev_err(ts->dev, "failed to read register %#02x: %d\n",
145 reg, error);
146 return error;
147 }
148
149 return val;
150}
151
152static int ad7879_write(struct ad7879 *ts, u8 reg, u16 val)
153{
154 int error;
155
156 error = regmap_write(ts->regmap, reg, val);
157 if (error) {
158 dev_err(ts->dev,
159 "failed to write %#04x to register %#02x: %d\n",
160 val, reg, error);
161 return error;
162 }
163
164 return 0;
165}
166
167static int ad7879_report(struct ad7879 *ts)
168{
169 struct input_dev *input_dev = ts->input;
170 unsigned Rt;
171 u16 x, y, z1, z2;
172
173 x = ts->conversion_data[AD7879_SEQ_XPOS] & MAX_12BIT;
174 y = ts->conversion_data[AD7879_SEQ_YPOS] & MAX_12BIT;
175 z1 = ts->conversion_data[AD7879_SEQ_Z1] & MAX_12BIT;
176 z2 = ts->conversion_data[AD7879_SEQ_Z2] & MAX_12BIT;
177
178 if (ts->swap_xy)
179 swap(x, y);
180
181 /*
182 * The samples processed here are already preprocessed by the AD7879.
183 * The preprocessing function consists of a median and an averaging
184 * filter. The combination of these two techniques provides a robust
185 * solution, discarding the spurious noise in the signal and keeping
186 * only the data of interest. The size of both filters is
187 * programmable. (dev.platform_data, see linux/platform_data/ad7879.h)
188 * Other user-programmable conversion controls include variable
189 * acquisition time, and first conversion delay. Up to 16 averages can
190 * be taken per conversion.
191 */
192
193 if (likely(x && z1)) {
194 /* compute touch pressure resistance using equation #1 */
195 Rt = (z2 - z1) * x * ts->x_plate_ohms;
196 Rt /= z1;
197 Rt = (Rt + 2047) >> 12;
198
199 /*
200 * Sample found inconsistent, pressure is beyond
201 * the maximum. Don't report it to user space.
202 */
203 if (Rt > input_abs_get_max(input_dev, ABS_PRESSURE))
204 return -EINVAL;
205
206 /*
207 * Note that we delay reporting events by one sample.
208 * This is done to avoid reporting last sample of the
209 * touch sequence, which may be incomplete if finger
210 * leaves the surface before last reading is taken.
211 */
212 if (timer_pending(&ts->timer)) {
213 /* Touch continues */
214 input_report_key(input_dev, BTN_TOUCH, 1);
215 input_report_abs(input_dev, ABS_X, ts->x);
216 input_report_abs(input_dev, ABS_Y, ts->y);
217 input_report_abs(input_dev, ABS_PRESSURE, ts->Rt);
218 input_sync(input_dev);
219 }
220
221 ts->x = x;
222 ts->y = y;
223 ts->Rt = Rt;
224
225 return 0;
226 }
227
228 return -EINVAL;
229}
230
231static void ad7879_ts_event_release(struct ad7879 *ts)
232{
233 struct input_dev *input_dev = ts->input;
234
235 input_report_abs(input_dev, ABS_PRESSURE, 0);
236 input_report_key(input_dev, BTN_TOUCH, 0);
237 input_sync(input_dev);
238}
239
240static void ad7879_timer(struct timer_list *t)
241{
242 struct ad7879 *ts = from_timer(ts, t, timer);
243
244 ad7879_ts_event_release(ts);
245}
246
247static irqreturn_t ad7879_irq(int irq, void *handle)
248{
249 struct ad7879 *ts = handle;
250
251 regmap_bulk_read(ts->regmap, AD7879_REG_XPLUS,
252 ts->conversion_data, AD7879_NR_SENSE);
253
254 if (!ad7879_report(ts))
255 mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
256
257 return IRQ_HANDLED;
258}
259
260static void __ad7879_enable(struct ad7879 *ts)
261{
262 ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
263 ad7879_write(ts, AD7879_REG_CTRL3, ts->cmd_crtl3);
264 ad7879_write(ts, AD7879_REG_CTRL1, ts->cmd_crtl1);
265
266 enable_irq(ts->irq);
267}
268
269static void __ad7879_disable(struct ad7879 *ts)
270{
271 u16 reg = (ts->cmd_crtl2 & ~AD7879_PM(-1)) |
272 AD7879_PM(AD7879_PM_SHUTDOWN);
273 disable_irq(ts->irq);
274
275 if (del_timer_sync(&ts->timer))
276 ad7879_ts_event_release(ts);
277
278 ad7879_write(ts, AD7879_REG_CTRL2, reg);
279}
280
281
282static int ad7879_open(struct input_dev *input)
283{
284 struct ad7879 *ts = input_get_drvdata(input);
285
286 /* protected by input->mutex */
287 if (!ts->disabled && !ts->suspended)
288 __ad7879_enable(ts);
289
290 return 0;
291}
292
293static void ad7879_close(struct input_dev* input)
294{
295 struct ad7879 *ts = input_get_drvdata(input);
296
297 /* protected by input->mutex */
298 if (!ts->disabled && !ts->suspended)
299 __ad7879_disable(ts);
300}
301
302static int __maybe_unused ad7879_suspend(struct device *dev)
303{
304 struct ad7879 *ts = dev_get_drvdata(dev);
305
306 mutex_lock(&ts->input->mutex);
307
308 if (!ts->suspended && !ts->disabled && ts->input->users)
309 __ad7879_disable(ts);
310
311 ts->suspended = true;
312
313 mutex_unlock(&ts->input->mutex);
314
315 return 0;
316}
317
318static int __maybe_unused ad7879_resume(struct device *dev)
319{
320 struct ad7879 *ts = dev_get_drvdata(dev);
321
322 mutex_lock(&ts->input->mutex);
323
324 if (ts->suspended && !ts->disabled && ts->input->users)
325 __ad7879_enable(ts);
326
327 ts->suspended = false;
328
329 mutex_unlock(&ts->input->mutex);
330
331 return 0;
332}
333
334SIMPLE_DEV_PM_OPS(ad7879_pm_ops, ad7879_suspend, ad7879_resume);
335EXPORT_SYMBOL(ad7879_pm_ops);
336
337static void ad7879_toggle(struct ad7879 *ts, bool disable)
338{
339 mutex_lock(&ts->input->mutex);
340
341 if (!ts->suspended && ts->input->users != 0) {
342
343 if (disable) {
344 if (ts->disabled)
345 __ad7879_enable(ts);
346 } else {
347 if (!ts->disabled)
348 __ad7879_disable(ts);
349 }
350 }
351
352 ts->disabled = disable;
353
354 mutex_unlock(&ts->input->mutex);
355}
356
357static ssize_t ad7879_disable_show(struct device *dev,
358 struct device_attribute *attr, char *buf)
359{
360 struct ad7879 *ts = dev_get_drvdata(dev);
361
362 return sprintf(buf, "%u\n", ts->disabled);
363}
364
365static ssize_t ad7879_disable_store(struct device *dev,
366 struct device_attribute *attr,
367 const char *buf, size_t count)
368{
369 struct ad7879 *ts = dev_get_drvdata(dev);
370 unsigned int val;
371 int error;
372
373 error = kstrtouint(buf, 10, &val);
374 if (error)
375 return error;
376
377 ad7879_toggle(ts, val);
378
379 return count;
380}
381
382static DEVICE_ATTR(disable, 0664, ad7879_disable_show, ad7879_disable_store);
383
384static struct attribute *ad7879_attributes[] = {
385 &dev_attr_disable.attr,
386 NULL
387};
388
389static const struct attribute_group ad7879_attr_group = {
390 .attrs = ad7879_attributes,
391};
392
393#ifdef CONFIG_GPIOLIB
394static int ad7879_gpio_direction_input(struct gpio_chip *chip,
395 unsigned gpio)
396{
397 struct ad7879 *ts = gpiochip_get_data(chip);
398 int err;
399
400 mutex_lock(&ts->mutex);
401 ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIODIR | AD7879_GPIOPOL;
402 err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
403 mutex_unlock(&ts->mutex);
404
405 return err;
406}
407
408static int ad7879_gpio_direction_output(struct gpio_chip *chip,
409 unsigned gpio, int level)
410{
411 struct ad7879 *ts = gpiochip_get_data(chip);
412 int err;
413
414 mutex_lock(&ts->mutex);
415 ts->cmd_crtl2 &= ~AD7879_GPIODIR;
416 ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIOPOL;
417 if (level)
418 ts->cmd_crtl2 |= AD7879_GPIO_DATA;
419 else
420 ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
421
422 err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
423 mutex_unlock(&ts->mutex);
424
425 return err;
426}
427
428static int ad7879_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
429{
430 struct ad7879 *ts = gpiochip_get_data(chip);
431 u16 val;
432
433 mutex_lock(&ts->mutex);
434 val = ad7879_read(ts, AD7879_REG_CTRL2);
435 mutex_unlock(&ts->mutex);
436
437 return !!(val & AD7879_GPIO_DATA);
438}
439
440static void ad7879_gpio_set_value(struct gpio_chip *chip,
441 unsigned gpio, int value)
442{
443 struct ad7879 *ts = gpiochip_get_data(chip);
444
445 mutex_lock(&ts->mutex);
446 if (value)
447 ts->cmd_crtl2 |= AD7879_GPIO_DATA;
448 else
449 ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
450
451 ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
452 mutex_unlock(&ts->mutex);
453}
454
455static int ad7879_gpio_add(struct ad7879 *ts,
456 const struct ad7879_platform_data *pdata)
457{
458 bool gpio_export;
459 int gpio_base;
460 int ret = 0;
461
462 if (pdata) {
463 gpio_export = pdata->gpio_export;
464 gpio_base = pdata->gpio_base;
465 } else {
466 gpio_export = device_property_read_bool(ts->dev,
467 "gpio-controller");
468 gpio_base = -1;
469 }
470
471 mutex_init(&ts->mutex);
472
473 if (gpio_export) {
474 ts->gc.direction_input = ad7879_gpio_direction_input;
475 ts->gc.direction_output = ad7879_gpio_direction_output;
476 ts->gc.get = ad7879_gpio_get_value;
477 ts->gc.set = ad7879_gpio_set_value;
478 ts->gc.can_sleep = 1;
479 ts->gc.base = gpio_base;
480 ts->gc.ngpio = 1;
481 ts->gc.label = "AD7879-GPIO";
482 ts->gc.owner = THIS_MODULE;
483 ts->gc.parent = ts->dev;
484
485 ret = devm_gpiochip_add_data(ts->dev, &ts->gc, ts);
486 if (ret)
487 dev_err(ts->dev, "failed to register gpio %d\n",
488 ts->gc.base);
489 }
490
491 return ret;
492}
493#else
494static int ad7879_gpio_add(struct ad7879 *ts,
495 const struct ad7879_platform_data *pdata)
496{
497 return 0;
498}
499#endif
500
501static 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
527int ad7879_probe(struct device *dev, struct regmap *regmap,
528 int irq, u16 bustype, u8 devid)
529{
530 struct ad7879_platform_data *pdata = dev_get_platdata(dev);
531 struct ad7879 *ts;
532 struct input_dev *input_dev;
533 int err;
534 u16 revid;
535
536 if (irq <= 0) {
537 dev_err(dev, "No IRQ specified\n");
538 return -EINVAL;
539 }
540
541 ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
542 if (!ts)
543 return -ENOMEM;
544
545 if (pdata) {
546 /* Platform data use swapped axis (backward compatibility) */
547 ts->swap_xy = !pdata->swap_xy;
548
549 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
550
551 ts->first_conversion_delay = pdata->first_conversion_delay;
552 ts->acquisition_time = pdata->acquisition_time;
553 ts->averaging = pdata->averaging;
554 ts->pen_down_acc_interval = pdata->pen_down_acc_interval;
555 ts->median = pdata->median;
556 } else {
557 err = ad7879_parse_dt(dev, ts);
558 if (err)
559 return err;
560 }
561
562 input_dev = devm_input_allocate_device(dev);
563 if (!input_dev) {
564 dev_err(dev, "Failed to allocate input device\n");
565 return -ENOMEM;
566 }
567
568 ts->dev = dev;
569 ts->input = input_dev;
570 ts->irq = irq;
571 ts->regmap = regmap;
572
573 timer_setup(&ts->timer, ad7879_timer, 0);
574 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev));
575
576 input_dev->name = "AD7879 Touchscreen";
577 input_dev->phys = ts->phys;
578 input_dev->dev.parent = dev;
579 input_dev->id.bustype = bustype;
580
581 input_dev->open = ad7879_open;
582 input_dev->close = ad7879_close;
583
584 input_set_drvdata(input_dev, ts);
585
586 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
587
588 if (pdata) {
589 input_set_abs_params(input_dev, ABS_X,
590 pdata->x_min ? : 0,
591 pdata->x_max ? : MAX_12BIT,
592 0, 0);
593 input_set_abs_params(input_dev, ABS_Y,
594 pdata->y_min ? : 0,
595 pdata->y_max ? : MAX_12BIT,
596 0, 0);
597 input_set_abs_params(input_dev, ABS_PRESSURE,
598 pdata->pressure_min,
599 pdata->pressure_max ? : ~0,
600 0, 0);
601 } else {
602 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
603 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
604 input_set_capability(input_dev, EV_ABS, ABS_PRESSURE);
605 touchscreen_parse_properties(input_dev, false, NULL);
606 if (!input_abs_get_max(input_dev, ABS_PRESSURE)) {
607 dev_err(dev, "Touchscreen pressure is not specified\n");
608 return -EINVAL;
609 }
610 }
611
612 err = ad7879_write(ts, AD7879_REG_CTRL2, AD7879_RESET);
613 if (err < 0) {
614 dev_err(dev, "Failed to write %s\n", input_dev->name);
615 return err;
616 }
617
618 revid = ad7879_read(ts, AD7879_REG_REVID);
619 input_dev->id.product = (revid & 0xff);
620 input_dev->id.version = revid >> 8;
621 if (input_dev->id.product != devid) {
622 dev_err(dev, "Failed to probe %s (%x vs %x)\n",
623 input_dev->name, devid, revid);
624 return -ENODEV;
625 }
626
627 ts->cmd_crtl3 = AD7879_YPLUS_BIT |
628 AD7879_XPLUS_BIT |
629 AD7879_Z2_BIT |
630 AD7879_Z1_BIT |
631 AD7879_TEMPMASK_BIT |
632 AD7879_AUXVBATMASK_BIT |
633 AD7879_GPIOALERTMASK_BIT;
634
635 ts->cmd_crtl2 = AD7879_PM(AD7879_PM_DYN) | AD7879_DFR |
636 AD7879_AVG(ts->averaging) |
637 AD7879_MFS(ts->median) |
638 AD7879_FCD(ts->first_conversion_delay);
639
640 ts->cmd_crtl1 = AD7879_MODE_INT | AD7879_MODE_SEQ1 |
641 AD7879_ACQ(ts->acquisition_time) |
642 AD7879_TMR(ts->pen_down_acc_interval);
643
644 err = devm_request_threaded_irq(dev, ts->irq, NULL, ad7879_irq,
645 IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
646 dev_name(dev), ts);
647 if (err) {
648 dev_err(dev, "Failed to request IRQ: %d\n", err);
649 return err;
650 }
651
652 __ad7879_disable(ts);
653
654 err = devm_device_add_group(dev, &ad7879_attr_group);
655 if (err)
656 return err;
657
658 err = ad7879_gpio_add(ts, pdata);
659 if (err)
660 return err;
661
662 err = input_register_device(input_dev);
663 if (err)
664 return err;
665
666 dev_set_drvdata(dev, ts);
667
668 return 0;
669}
670EXPORT_SYMBOL(ad7879_probe);
671
672MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
673MODULE_DESCRIPTION("AD7879(-1) touchscreen Driver");
674MODULE_LICENSE("GPL");