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 
97 enum {
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 
108 struct 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 
ad7879_read(struct ad7879 * ts,u8 reg)137 static 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 
ad7879_write(struct ad7879 * ts,u8 reg,u16 val)152 static 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 
ad7879_report(struct ad7879 * ts)167 static 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 
ad7879_ts_event_release(struct ad7879 * ts)231 static 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 
ad7879_timer(struct timer_list * t)240 static 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 
ad7879_irq(int irq,void * handle)247 static 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 
__ad7879_enable(struct ad7879 * ts)260 static 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 
__ad7879_disable(struct ad7879 * ts)269 static 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 
ad7879_open(struct input_dev * input)282 static 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 
ad7879_close(struct input_dev * input)293 static 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 
ad7879_suspend(struct device * dev)302 static 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 
ad7879_resume(struct device * dev)318 static 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 
334 SIMPLE_DEV_PM_OPS(ad7879_pm_ops, ad7879_suspend, ad7879_resume);
335 EXPORT_SYMBOL(ad7879_pm_ops);
336 
ad7879_toggle(struct ad7879 * ts,bool disable)337 static 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 
ad7879_disable_show(struct device * dev,struct device_attribute * attr,char * buf)357 static 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 
ad7879_disable_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)365 static 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 
382 static DEVICE_ATTR(disable, 0664, ad7879_disable_show, ad7879_disable_store);
383 
384 static struct attribute *ad7879_attributes[] = {
385 	&dev_attr_disable.attr,
386 	NULL
387 };
388 
389 static const struct attribute_group ad7879_attr_group = {
390 	.attrs = ad7879_attributes,
391 };
392 
393 #ifdef CONFIG_GPIOLIB
ad7879_gpio_direction_input(struct gpio_chip * chip,unsigned gpio)394 static 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 
ad7879_gpio_direction_output(struct gpio_chip * chip,unsigned gpio,int level)408 static 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 
ad7879_gpio_get_value(struct gpio_chip * chip,unsigned gpio)428 static 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 
ad7879_gpio_set_value(struct gpio_chip * chip,unsigned gpio,int value)440 static 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 
ad7879_gpio_add(struct ad7879 * ts,const struct ad7879_platform_data * pdata)455 static 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
ad7879_gpio_add(struct ad7879 * ts,const struct ad7879_platform_data * pdata)494 static int ad7879_gpio_add(struct ad7879 *ts,
495 			   const struct ad7879_platform_data *pdata)
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_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 }
670 EXPORT_SYMBOL(ad7879_probe);
671 
672 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
673 MODULE_DESCRIPTION("AD7879(-1) touchscreen Driver");
674 MODULE_LICENSE("GPL");
675