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/slab.h>
30#include <linux/spi/spi.h>
31#include <linux/i2c.h>
32#include <linux/gpio.h>
33
34#include <linux/spi/ad7879.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_XPOS  = 0,
98	AD7879_SEQ_YPOS  = 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	const struct ad7879_bus_ops *bops;
109
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			pressure_max;
130	u16			cmd_crtl1;
131	u16			cmd_crtl2;
132	u16			cmd_crtl3;
133	int			x;
134	int			y;
135	int			Rt;
136};
137
138static int ad7879_read(struct ad7879 *ts, u8 reg)
139{
140	return ts->bops->read(ts->dev, reg);
141}
142
143static int ad7879_multi_read(struct ad7879 *ts, u8 first_reg, u8 count, u16 *buf)
144{
145	return ts->bops->multi_read(ts->dev, first_reg, count, buf);
146}
147
148static int ad7879_write(struct ad7879 *ts, u8 reg, u16 val)
149{
150	return ts->bops->write(ts->dev, reg, val);
151}
152
153static int ad7879_report(struct ad7879 *ts)
154{
155	struct input_dev *input_dev = ts->input;
156	unsigned Rt;
157	u16 x, y, z1, z2;
158
159	x = ts->conversion_data[AD7879_SEQ_XPOS] & MAX_12BIT;
160	y = ts->conversion_data[AD7879_SEQ_YPOS] & MAX_12BIT;
161	z1 = ts->conversion_data[AD7879_SEQ_Z1] & MAX_12BIT;
162	z2 = ts->conversion_data[AD7879_SEQ_Z2] & MAX_12BIT;
163
164	if (ts->swap_xy)
165		swap(x, y);
166
167	/*
168	 * The samples processed here are already preprocessed by the AD7879.
169	 * The preprocessing function consists of a median and an averaging
170	 * filter.  The combination of these two techniques provides a robust
171	 * solution, discarding the spurious noise in the signal and keeping
172	 * only the data of interest.  The size of both filters is
173	 * programmable. (dev.platform_data, see linux/spi/ad7879.h) Other
174	 * user-programmable conversion controls include variable acquisition
175	 * time, and first conversion delay. Up to 16 averages can be taken
176	 * per conversion.
177	 */
178
179	if (likely(x && z1)) {
180		/* compute touch pressure resistance using equation #1 */
181		Rt = (z2 - z1) * x * ts->x_plate_ohms;
182		Rt /= z1;
183		Rt = (Rt + 2047) >> 12;
184
185		/*
186		 * Sample found inconsistent, pressure is beyond
187		 * the maximum. Don't report it to user space.
188		 */
189		if (Rt > ts->pressure_max)
190			return -EINVAL;
191
192		/*
193		 * Note that we delay reporting events by one sample.
194		 * This is done to avoid reporting last sample of the
195		 * touch sequence, which may be incomplete if finger
196		 * leaves the surface before last reading is taken.
197		 */
198		if (timer_pending(&ts->timer)) {
199			/* Touch continues */
200			input_report_key(input_dev, BTN_TOUCH, 1);
201			input_report_abs(input_dev, ABS_X, ts->x);
202			input_report_abs(input_dev, ABS_Y, ts->y);
203			input_report_abs(input_dev, ABS_PRESSURE, ts->Rt);
204			input_sync(input_dev);
205		}
206
207		ts->x = x;
208		ts->y = y;
209		ts->Rt = Rt;
210
211		return 0;
212	}
213
214	return -EINVAL;
215}
216
217static void ad7879_ts_event_release(struct ad7879 *ts)
218{
219	struct input_dev *input_dev = ts->input;
220
221	input_report_abs(input_dev, ABS_PRESSURE, 0);
222	input_report_key(input_dev, BTN_TOUCH, 0);
223	input_sync(input_dev);
224}
225
226static void ad7879_timer(unsigned long handle)
227{
228	struct ad7879 *ts = (void *)handle;
229
230	ad7879_ts_event_release(ts);
231}
232
233static irqreturn_t ad7879_irq(int irq, void *handle)
234{
235	struct ad7879 *ts = handle;
236
237	ad7879_multi_read(ts, AD7879_REG_XPLUS, AD7879_NR_SENSE, ts->conversion_data);
238
239	if (!ad7879_report(ts))
240		mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
241
242	return IRQ_HANDLED;
243}
244
245static void __ad7879_enable(struct ad7879 *ts)
246{
247	ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
248	ad7879_write(ts, AD7879_REG_CTRL3, ts->cmd_crtl3);
249	ad7879_write(ts, AD7879_REG_CTRL1, ts->cmd_crtl1);
250
251	enable_irq(ts->irq);
252}
253
254static void __ad7879_disable(struct ad7879 *ts)
255{
256	u16 reg = (ts->cmd_crtl2 & ~AD7879_PM(-1)) |
257		AD7879_PM(AD7879_PM_SHUTDOWN);
258	disable_irq(ts->irq);
259
260	if (del_timer_sync(&ts->timer))
261		ad7879_ts_event_release(ts);
262
263	ad7879_write(ts, AD7879_REG_CTRL2, reg);
264}
265
266
267static int ad7879_open(struct input_dev *input)
268{
269	struct ad7879 *ts = input_get_drvdata(input);
270
271	/* protected by input->mutex */
272	if (!ts->disabled && !ts->suspended)
273		__ad7879_enable(ts);
274
275	return 0;
276}
277
278static void ad7879_close(struct input_dev* input)
279{
280	struct ad7879 *ts = input_get_drvdata(input);
281
282	/* protected by input->mutex */
283	if (!ts->disabled && !ts->suspended)
284		__ad7879_disable(ts);
285}
286
287static int __maybe_unused ad7879_suspend(struct device *dev)
288{
289	struct ad7879 *ts = dev_get_drvdata(dev);
290
291	mutex_lock(&ts->input->mutex);
292
293	if (!ts->suspended && !ts->disabled && ts->input->users)
294		__ad7879_disable(ts);
295
296	ts->suspended = true;
297
298	mutex_unlock(&ts->input->mutex);
299
300	return 0;
301}
302
303static int __maybe_unused ad7879_resume(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_enable(ts);
311
312	ts->suspended = false;
313
314	mutex_unlock(&ts->input->mutex);
315
316	return 0;
317}
318
319SIMPLE_DEV_PM_OPS(ad7879_pm_ops, ad7879_suspend, ad7879_resume);
320EXPORT_SYMBOL(ad7879_pm_ops);
321
322static void ad7879_toggle(struct ad7879 *ts, bool disable)
323{
324	mutex_lock(&ts->input->mutex);
325
326	if (!ts->suspended && ts->input->users != 0) {
327
328		if (disable) {
329			if (ts->disabled)
330				__ad7879_enable(ts);
331		} else {
332			if (!ts->disabled)
333				__ad7879_disable(ts);
334		}
335	}
336
337	ts->disabled = disable;
338
339	mutex_unlock(&ts->input->mutex);
340}
341
342static ssize_t ad7879_disable_show(struct device *dev,
343				     struct device_attribute *attr, char *buf)
344{
345	struct ad7879 *ts = dev_get_drvdata(dev);
346
347	return sprintf(buf, "%u\n", ts->disabled);
348}
349
350static ssize_t ad7879_disable_store(struct device *dev,
351				     struct device_attribute *attr,
352				     const char *buf, size_t count)
353{
354	struct ad7879 *ts = dev_get_drvdata(dev);
355	unsigned int val;
356	int error;
357
358	error = kstrtouint(buf, 10, &val);
359	if (error)
360		return error;
361
362	ad7879_toggle(ts, val);
363
364	return count;
365}
366
367static DEVICE_ATTR(disable, 0664, ad7879_disable_show, ad7879_disable_store);
368
369static struct attribute *ad7879_attributes[] = {
370	&dev_attr_disable.attr,
371	NULL
372};
373
374static const struct attribute_group ad7879_attr_group = {
375	.attrs = ad7879_attributes,
376};
377
378#ifdef CONFIG_GPIOLIB
379static int ad7879_gpio_direction_input(struct gpio_chip *chip,
380					unsigned gpio)
381{
382	struct ad7879 *ts = container_of(chip, struct ad7879, gc);
383	int err;
384
385	mutex_lock(&ts->mutex);
386	ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIODIR | AD7879_GPIOPOL;
387	err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
388	mutex_unlock(&ts->mutex);
389
390	return err;
391}
392
393static int ad7879_gpio_direction_output(struct gpio_chip *chip,
394					unsigned gpio, int level)
395{
396	struct ad7879 *ts = container_of(chip, struct ad7879, gc);
397	int err;
398
399	mutex_lock(&ts->mutex);
400	ts->cmd_crtl2 &= ~AD7879_GPIODIR;
401	ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIOPOL;
402	if (level)
403		ts->cmd_crtl2 |= AD7879_GPIO_DATA;
404	else
405		ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
406
407	err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
408	mutex_unlock(&ts->mutex);
409
410	return err;
411}
412
413static int ad7879_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
414{
415	struct ad7879 *ts = container_of(chip, struct ad7879, gc);
416	u16 val;
417
418	mutex_lock(&ts->mutex);
419	val = ad7879_read(ts, AD7879_REG_CTRL2);
420	mutex_unlock(&ts->mutex);
421
422	return !!(val & AD7879_GPIO_DATA);
423}
424
425static void ad7879_gpio_set_value(struct gpio_chip *chip,
426				  unsigned gpio, int value)
427{
428	struct ad7879 *ts = container_of(chip, struct ad7879, gc);
429
430	mutex_lock(&ts->mutex);
431	if (value)
432		ts->cmd_crtl2 |= AD7879_GPIO_DATA;
433	else
434		ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
435
436	ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
437	mutex_unlock(&ts->mutex);
438}
439
440static int ad7879_gpio_add(struct ad7879 *ts,
441			   const struct ad7879_platform_data *pdata)
442{
443	int ret = 0;
444
445	mutex_init(&ts->mutex);
446
447	if (pdata->gpio_export) {
448		ts->gc.direction_input = ad7879_gpio_direction_input;
449		ts->gc.direction_output = ad7879_gpio_direction_output;
450		ts->gc.get = ad7879_gpio_get_value;
451		ts->gc.set = ad7879_gpio_set_value;
452		ts->gc.can_sleep = 1;
453		ts->gc.base = pdata->gpio_base;
454		ts->gc.ngpio = 1;
455		ts->gc.label = "AD7879-GPIO";
456		ts->gc.owner = THIS_MODULE;
457		ts->gc.dev = ts->dev;
458
459		ret = gpiochip_add(&ts->gc);
460		if (ret)
461			dev_err(ts->dev, "failed to register gpio %d\n",
462				ts->gc.base);
463	}
464
465	return ret;
466}
467
468static void ad7879_gpio_remove(struct ad7879 *ts)
469{
470	const struct ad7879_platform_data *pdata = dev_get_platdata(ts->dev);
471
472	if (pdata->gpio_export)
473		gpiochip_remove(&ts->gc);
474
475}
476#else
477static inline int ad7879_gpio_add(struct ad7879 *ts,
478				  const struct ad7879_platform_data *pdata)
479{
480	return 0;
481}
482
483static inline void ad7879_gpio_remove(struct ad7879 *ts)
484{
485}
486#endif
487
488struct ad7879 *ad7879_probe(struct device *dev, u8 devid, unsigned int irq,
489			    const struct ad7879_bus_ops *bops)
490{
491	struct ad7879_platform_data *pdata = dev_get_platdata(dev);
492	struct ad7879 *ts;
493	struct input_dev *input_dev;
494	int err;
495	u16 revid;
496
497	if (!irq) {
498		dev_err(dev, "no IRQ?\n");
499		err = -EINVAL;
500		goto err_out;
501	}
502
503	if (!pdata) {
504		dev_err(dev, "no platform data?\n");
505		err = -EINVAL;
506		goto err_out;
507	}
508
509	ts = kzalloc(sizeof(*ts), GFP_KERNEL);
510	input_dev = input_allocate_device();
511	if (!ts || !input_dev) {
512		err = -ENOMEM;
513		goto err_free_mem;
514	}
515
516	ts->bops = bops;
517	ts->dev = dev;
518	ts->input = input_dev;
519	ts->irq = irq;
520	ts->swap_xy = pdata->swap_xy;
521
522	setup_timer(&ts->timer, ad7879_timer, (unsigned long) ts);
523
524	ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
525	ts->pressure_max = pdata->pressure_max ? : ~0;
526
527	ts->first_conversion_delay = pdata->first_conversion_delay;
528	ts->acquisition_time = pdata->acquisition_time;
529	ts->averaging = pdata->averaging;
530	ts->pen_down_acc_interval = pdata->pen_down_acc_interval;
531	ts->median = pdata->median;
532
533	snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev));
534
535	input_dev->name = "AD7879 Touchscreen";
536	input_dev->phys = ts->phys;
537	input_dev->dev.parent = dev;
538	input_dev->id.bustype = bops->bustype;
539
540	input_dev->open = ad7879_open;
541	input_dev->close = ad7879_close;
542
543	input_set_drvdata(input_dev, ts);
544
545	__set_bit(EV_ABS, input_dev->evbit);
546	__set_bit(ABS_X, input_dev->absbit);
547	__set_bit(ABS_Y, input_dev->absbit);
548	__set_bit(ABS_PRESSURE, input_dev->absbit);
549
550	__set_bit(EV_KEY, input_dev->evbit);
551	__set_bit(BTN_TOUCH, input_dev->keybit);
552
553	input_set_abs_params(input_dev, ABS_X,
554			pdata->x_min ? : 0,
555			pdata->x_max ? : MAX_12BIT,
556			0, 0);
557	input_set_abs_params(input_dev, ABS_Y,
558			pdata->y_min ? : 0,
559			pdata->y_max ? : MAX_12BIT,
560			0, 0);
561	input_set_abs_params(input_dev, ABS_PRESSURE,
562			pdata->pressure_min, pdata->pressure_max, 0, 0);
563
564	err = ad7879_write(ts, AD7879_REG_CTRL2, AD7879_RESET);
565	if (err < 0) {
566		dev_err(dev, "Failed to write %s\n", input_dev->name);
567		goto err_free_mem;
568	}
569
570	revid = ad7879_read(ts, AD7879_REG_REVID);
571	input_dev->id.product = (revid & 0xff);
572	input_dev->id.version = revid >> 8;
573	if (input_dev->id.product != devid) {
574		dev_err(dev, "Failed to probe %s (%x vs %x)\n",
575			input_dev->name, devid, revid);
576		err = -ENODEV;
577		goto err_free_mem;
578	}
579
580	ts->cmd_crtl3 = AD7879_YPLUS_BIT |
581			AD7879_XPLUS_BIT |
582			AD7879_Z2_BIT |
583			AD7879_Z1_BIT |
584			AD7879_TEMPMASK_BIT |
585			AD7879_AUXVBATMASK_BIT |
586			AD7879_GPIOALERTMASK_BIT;
587
588	ts->cmd_crtl2 = AD7879_PM(AD7879_PM_DYN) | AD7879_DFR |
589			AD7879_AVG(ts->averaging) |
590			AD7879_MFS(ts->median) |
591			AD7879_FCD(ts->first_conversion_delay);
592
593	ts->cmd_crtl1 = AD7879_MODE_INT | AD7879_MODE_SEQ1 |
594			AD7879_ACQ(ts->acquisition_time) |
595			AD7879_TMR(ts->pen_down_acc_interval);
596
597	err = request_threaded_irq(ts->irq, NULL, ad7879_irq,
598				   IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
599				   dev_name(dev), ts);
600	if (err) {
601		dev_err(dev, "irq %d busy?\n", ts->irq);
602		goto err_free_mem;
603	}
604
605	__ad7879_disable(ts);
606
607	err = sysfs_create_group(&dev->kobj, &ad7879_attr_group);
608	if (err)
609		goto err_free_irq;
610
611	err = ad7879_gpio_add(ts, pdata);
612	if (err)
613		goto err_remove_attr;
614
615	err = input_register_device(input_dev);
616	if (err)
617		goto err_remove_gpio;
618
619	return ts;
620
621err_remove_gpio:
622	ad7879_gpio_remove(ts);
623err_remove_attr:
624	sysfs_remove_group(&dev->kobj, &ad7879_attr_group);
625err_free_irq:
626	free_irq(ts->irq, ts);
627err_free_mem:
628	input_free_device(input_dev);
629	kfree(ts);
630err_out:
631	return ERR_PTR(err);
632}
633EXPORT_SYMBOL(ad7879_probe);
634
635void ad7879_remove(struct ad7879 *ts)
636{
637	ad7879_gpio_remove(ts);
638	sysfs_remove_group(&ts->dev->kobj, &ad7879_attr_group);
639	free_irq(ts->irq, ts);
640	input_unregister_device(ts->input);
641	kfree(ts);
642}
643EXPORT_SYMBOL(ad7879_remove);
644
645MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
646MODULE_DESCRIPTION("AD7879(-1) touchscreen Driver");
647MODULE_LICENSE("GPL");
648