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/drivers/input/touchscreen/ad7879.c

http://github.com/mirrors/linux
C | 635 lines | 466 code | 119 blank | 50 comment | 46 complexity | 888d942e034bc3add42a21da9061bc6a MD5 | raw file
  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 && ts->input->users)
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 && ts->input->users)
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 && ts->input->users != 0) {
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
394#ifdef CONFIG_GPIOLIB
395static 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
409static 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
429static 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
441static 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
456static 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
485static int ad7879_gpio_add(struct ad7879 *ts)
486{
487	return 0;
488}
489#endif
490
491static 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
517int 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}
631EXPORT_SYMBOL(ad7879_probe);
632
633MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
634MODULE_DESCRIPTION("AD7879(-1) touchscreen Driver");
635MODULE_LICENSE("GPL");