ad7879.c

  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
 96enum {
 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
107struct 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
136static 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
151static 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
166static 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
230static 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
239static 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
246static 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
262static 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
271static 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
284static 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
295static 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
304static 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
320static 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
336SIMPLE_DEV_PM_OPS(ad7879_pm_ops, ad7879_suspend, ad7879_resume);
337EXPORT_SYMBOL(ad7879_pm_ops);
338
339static 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
359static 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
367static 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
384static DEVICE_ATTR(disable, 0664, ad7879_disable_show, ad7879_disable_store);
385
386static struct attribute *ad7879_attributes[] = {
387	&dev_attr_disable.attr,
388	NULL
389};
390
391static const struct attribute_group ad7879_attr_group = {
392	.attrs = ad7879_attributes,
393};
394
395const struct attribute_group *ad7879_groups[] = {
396	&ad7879_attr_group,
397	NULL
398};
399EXPORT_SYMBOL_GPL(ad7879_groups);
400
401#ifdef CONFIG_GPIOLIB
402static 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
416static 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
436static 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
448static 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
466static 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
495static int ad7879_gpio_add(struct ad7879 *ts)
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 *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}
637EXPORT_SYMBOL(ad7879_probe);
638
639MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
640MODULE_DESCRIPTION("AD7879(-1) touchscreen Driver");
641MODULE_LICENSE("GPL");