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/init.h>
26#include <linux/delay.h>
27#include <linux/input.h>
28#include <linux/interrupt.h>
29#include <linux/irq.h>
30#include <linux/slab.h>
31#include <linux/spi/spi.h>
32#include <linux/i2c.h>
33#include <linux/gpio.h>
34
35#include <linux/spi/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_XPOS  = 0,
99	AD7879_SEQ_YPOS  = 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	const struct ad7879_bus_ops *bops;
110
111	struct device		*dev;
112	struct input_dev	*input;
113	struct timer_list	timer;
114#ifdef CONFIG_GPIOLIB
115	struct gpio_chip	gc;
116	struct mutex		mutex;
117#endif
118	unsigned int		irq;
119	bool			disabled;	/* P: input->mutex */
120	bool			suspended;	/* P: input->mutex */
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	/*
165	 * The samples processed here are already preprocessed by the AD7879.
166	 * The preprocessing function consists of a median and an averaging
167	 * filter.  The combination of these two techniques provides a robust
168	 * solution, discarding the spurious noise in the signal and keeping
169	 * only the data of interest.  The size of both filters is
170	 * programmable. (dev.platform_data, see linux/spi/ad7879.h) Other
171	 * user-programmable conversion controls include variable acquisition
172	 * time, and first conversion delay. Up to 16 averages can be taken
173	 * per conversion.
174	 */
175
176	if (likely(x && z1)) {
177		/* compute touch pressure resistance using equation #1 */
178		Rt = (z2 - z1) * x * ts->x_plate_ohms;
179		Rt /= z1;
180		Rt = (Rt + 2047) >> 12;
181
182		/*
183		 * Sample found inconsistent, pressure is beyond
184		 * the maximum. Don't report it to user space.
185		 */
186		if (Rt > ts->pressure_max)
187			return -EINVAL;
188
189		/*
190		 * Note that we delay reporting events by one sample.
191		 * This is done to avoid reporting last sample of the
192		 * touch sequence, which may be incomplete if finger
193		 * leaves the surface before last reading is taken.
194		 */
195		if (timer_pending(&ts->timer)) {
196			/* Touch continues */
197			input_report_key(input_dev, BTN_TOUCH, 1);
198			input_report_abs(input_dev, ABS_X, ts->x);
199			input_report_abs(input_dev, ABS_Y, ts->y);
200			input_report_abs(input_dev, ABS_PRESSURE, ts->Rt);
201			input_sync(input_dev);
202		}
203
204		ts->x = x;
205		ts->y = y;
206		ts->Rt = Rt;
207
208		return 0;
209	}
210
211	return -EINVAL;
212}
213
214static void ad7879_ts_event_release(struct ad7879 *ts)
215{
216	struct input_dev *input_dev = ts->input;
217
218	input_report_abs(input_dev, ABS_PRESSURE, 0);
219	input_report_key(input_dev, BTN_TOUCH, 0);
220	input_sync(input_dev);
221}
222
223static void ad7879_timer(unsigned long handle)
224{
225	struct ad7879 *ts = (void *)handle;
226
227	ad7879_ts_event_release(ts);
228}
229
230static irqreturn_t ad7879_irq(int irq, void *handle)
231{
232	struct ad7879 *ts = handle;
233
234	ad7879_multi_read(ts, AD7879_REG_XPLUS, AD7879_NR_SENSE, ts->conversion_data);
235
236	if (!ad7879_report(ts))
237		mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
238
239	return IRQ_HANDLED;
240}
241
242static void __ad7879_enable(struct ad7879 *ts)
243{
244	ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
245	ad7879_write(ts, AD7879_REG_CTRL3, ts->cmd_crtl3);
246	ad7879_write(ts, AD7879_REG_CTRL1, ts->cmd_crtl1);
247
248	enable_irq(ts->irq);
249}
250
251static void __ad7879_disable(struct ad7879 *ts)
252{
253	u16 reg = (ts->cmd_crtl2 & ~AD7879_PM(-1)) |
254		AD7879_PM(AD7879_PM_SHUTDOWN);
255	disable_irq(ts->irq);
256
257	if (del_timer_sync(&ts->timer))
258		ad7879_ts_event_release(ts);
259
260	ad7879_write(ts, AD7879_REG_CTRL2, reg);
261}
262
263
264static int ad7879_open(struct input_dev *input)
265{
266	struct ad7879 *ts = input_get_drvdata(input);
267
268	/* protected by input->mutex */
269	if (!ts->disabled && !ts->suspended)
270		__ad7879_enable(ts);
271
272	return 0;
273}
274
275static void ad7879_close(struct input_dev* input)
276{
277	struct ad7879 *ts = input_get_drvdata(input);
278
279	/* protected by input->mutex */
280	if (!ts->disabled && !ts->suspended)
281		__ad7879_disable(ts);
282}
283
284#ifdef CONFIG_PM_SLEEP
285static int ad7879_suspend(struct device *dev)
286{
287	struct ad7879 *ts = dev_get_drvdata(dev);
288
289	mutex_lock(&ts->input->mutex);
290
291	if (!ts->suspended && !ts->disabled && ts->input->users)
292		__ad7879_disable(ts);
293
294	ts->suspended = true;
295
296	mutex_unlock(&ts->input->mutex);
297
298	return 0;
299}
300
301static int ad7879_resume(struct device *dev)
302{
303	struct ad7879 *ts = dev_get_drvdata(dev);
304
305	mutex_lock(&ts->input->mutex);
306
307	if (ts->suspended && !ts->disabled && ts->input->users)
308		__ad7879_enable(ts);
309
310	ts->suspended = false;
311
312	mutex_unlock(&ts->input->mutex);
313
314	return 0;
315}
316#endif
317
318SIMPLE_DEV_PM_OPS(ad7879_pm_ops, ad7879_suspend, ad7879_resume);
319EXPORT_SYMBOL(ad7879_pm_ops);
320
321static void ad7879_toggle(struct ad7879 *ts, bool disable)
322{
323	mutex_lock(&ts->input->mutex);
324
325	if (!ts->suspended && ts->input->users != 0) {
326
327		if (disable) {
328			if (ts->disabled)
329				__ad7879_enable(ts);
330		} else {
331			if (!ts->disabled)
332				__ad7879_disable(ts);
333		}
334	}
335
336	ts->disabled = disable;
337
338	mutex_unlock(&ts->input->mutex);
339}
340
341static ssize_t ad7879_disable_show(struct device *dev,
342				     struct device_attribute *attr, char *buf)
343{
344	struct ad7879 *ts = dev_get_drvdata(dev);
345
346	return sprintf(buf, "%u\n", ts->disabled);
347}
348
349static ssize_t ad7879_disable_store(struct device *dev,
350				     struct device_attribute *attr,
351				     const char *buf, size_t count)
352{
353	struct ad7879 *ts = dev_get_drvdata(dev);
354	unsigned int val;
355	int error;
356
357	error = kstrtouint(buf, 10, &val);
358	if (error)
359		return error;
360
361	ad7879_toggle(ts, val);
362
363	return count;
364}
365
366static DEVICE_ATTR(disable, 0664, ad7879_disable_show, ad7879_disable_store);
367
368static struct attribute *ad7879_attributes[] = {
369	&dev_attr_disable.attr,
370	NULL
371};
372
373static const struct attribute_group ad7879_attr_group = {
374	.attrs = ad7879_attributes,
375};
376
377#ifdef CONFIG_GPIOLIB
378static int ad7879_gpio_direction_input(struct gpio_chip *chip,
379					unsigned gpio)
380{
381	struct ad7879 *ts = container_of(chip, struct ad7879, gc);
382	int err;
383
384	mutex_lock(&ts->mutex);
385	ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIODIR | AD7879_GPIOPOL;
386	err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
387	mutex_unlock(&ts->mutex);
388
389	return err;
390}
391
392static int ad7879_gpio_direction_output(struct gpio_chip *chip,
393					unsigned gpio, int level)
394{
395	struct ad7879 *ts = container_of(chip, struct ad7879, gc);
396	int err;
397
398	mutex_lock(&ts->mutex);
399	ts->cmd_crtl2 &= ~AD7879_GPIODIR;
400	ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIOPOL;
401	if (level)
402		ts->cmd_crtl2 |= AD7879_GPIO_DATA;
403	else
404		ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
405
406	err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
407	mutex_unlock(&ts->mutex);
408
409	return err;
410}
411
412static int ad7879_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
413{
414	struct ad7879 *ts = container_of(chip, struct ad7879, gc);
415	u16 val;
416
417	mutex_lock(&ts->mutex);
418	val = ad7879_read(ts, AD7879_REG_CTRL2);
419	mutex_unlock(&ts->mutex);
420
421	return !!(val & AD7879_GPIO_DATA);
422}
423
424static void ad7879_gpio_set_value(struct gpio_chip *chip,
425				  unsigned gpio, int value)
426{
427	struct ad7879 *ts = container_of(chip, struct ad7879, gc);
428
429	mutex_lock(&ts->mutex);
430	if (value)
431		ts->cmd_crtl2 |= AD7879_GPIO_DATA;
432	else
433		ts->cmd_crtl2 &= ~AD7879_GPIO_DATA;
434
435	ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2);
436	mutex_unlock(&ts->mutex);
437}
438
439static int ad7879_gpio_add(struct ad7879 *ts,
440			   const struct ad7879_platform_data *pdata)
441{
442	int ret = 0;
443
444	mutex_init(&ts->mutex);
445
446	if (pdata->gpio_export) {
447		ts->gc.direction_input = ad7879_gpio_direction_input;
448		ts->gc.direction_output = ad7879_gpio_direction_output;
449		ts->gc.get = ad7879_gpio_get_value;
450		ts->gc.set = ad7879_gpio_set_value;
451		ts->gc.can_sleep = 1;
452		ts->gc.base = pdata->gpio_base;
453		ts->gc.ngpio = 1;
454		ts->gc.label = "AD7879-GPIO";
455		ts->gc.owner = THIS_MODULE;
456		ts->gc.dev = ts->dev;
457
458		ret = gpiochip_add(&ts->gc);
459		if (ret)
460			dev_err(ts->dev, "failed to register gpio %d\n",
461				ts->gc.base);
462	}
463
464	return ret;
465}
466
467static void ad7879_gpio_remove(struct ad7879 *ts)
468{
469	const struct ad7879_platform_data *pdata = ts->dev->platform_data;
470	int ret;
471
472	if (pdata->gpio_export) {
473		ret = gpiochip_remove(&ts->gc);
474		if (ret)
475			dev_err(ts->dev, "failed to remove gpio %d\n",
476				ts->gc.base);
477	}
478}
479#else
480static inline int ad7879_gpio_add(struct ad7879 *ts,
481				  const struct ad7879_platform_data *pdata)
482{
483	return 0;
484}
485
486static inline void ad7879_gpio_remove(struct ad7879 *ts)
487{
488}
489#endif
490
491struct ad7879 *ad7879_probe(struct device *dev, u8 devid, unsigned int irq,
492			    const struct ad7879_bus_ops *bops)
493{
494	struct ad7879_platform_data *pdata = dev->platform_data;
495	struct ad7879 *ts;
496	struct input_dev *input_dev;
497	int err;
498	u16 revid;
499
500	if (!irq) {
501		dev_err(dev, "no IRQ?\n");
502		err = -EINVAL;
503		goto err_out;
504	}
505
506	if (!pdata) {
507		dev_err(dev, "no platform data?\n");
508		err = -EINVAL;
509		goto err_out;
510	}
511
512	ts = kzalloc(sizeof(*ts), GFP_KERNEL);
513	input_dev = input_allocate_device();
514	if (!ts || !input_dev) {
515		err = -ENOMEM;
516		goto err_free_mem;
517	}
518
519	ts->bops = bops;
520	ts->dev = dev;
521	ts->input = input_dev;
522	ts->irq = irq;
523
524	setup_timer(&ts->timer, ad7879_timer, (unsigned long) ts);
525
526	ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
527	ts->pressure_max = pdata->pressure_max ? : ~0;
528
529	ts->first_conversion_delay = pdata->first_conversion_delay;
530	ts->acquisition_time = pdata->acquisition_time;
531	ts->averaging = pdata->averaging;
532	ts->pen_down_acc_interval = pdata->pen_down_acc_interval;
533	ts->median = pdata->median;
534
535	snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev));
536
537	input_dev->name = "AD7879 Touchscreen";
538	input_dev->phys = ts->phys;
539	input_dev->dev.parent = dev;
540	input_dev->id.bustype = bops->bustype;
541
542	input_dev->open = ad7879_open;
543	input_dev->close = ad7879_close;
544
545	input_set_drvdata(input_dev, ts);
546
547	__set_bit(EV_ABS, input_dev->evbit);
548	__set_bit(ABS_X, input_dev->absbit);
549	__set_bit(ABS_Y, input_dev->absbit);
550	__set_bit(ABS_PRESSURE, input_dev->absbit);
551
552	__set_bit(EV_KEY, input_dev->evbit);
553	__set_bit(BTN_TOUCH, input_dev->keybit);
554
555	input_set_abs_params(input_dev, ABS_X,
556			pdata->x_min ? : 0,
557			pdata->x_max ? : MAX_12BIT,
558			0, 0);
559	input_set_abs_params(input_dev, ABS_Y,
560			pdata->y_min ? : 0,
561			pdata->y_max ? : MAX_12BIT,
562			0, 0);
563	input_set_abs_params(input_dev, ABS_PRESSURE,
564			pdata->pressure_min, pdata->pressure_max, 0, 0);
565
566	err = ad7879_write(ts, AD7879_REG_CTRL2, AD7879_RESET);
567	if (err < 0) {
568		dev_err(dev, "Failed to write %s\n", input_dev->name);
569		goto err_free_mem;
570	}
571
572	revid = ad7879_read(ts, AD7879_REG_REVID);
573	input_dev->id.product = (revid & 0xff);
574	input_dev->id.version = revid >> 8;
575	if (input_dev->id.product != devid) {
576		dev_err(dev, "Failed to probe %s (%x vs %x)\n",
577			input_dev->name, devid, revid);
578		err = -ENODEV;
579		goto err_free_mem;
580	}
581
582	ts->cmd_crtl3 = AD7879_YPLUS_BIT |
583			AD7879_XPLUS_BIT |
584			AD7879_Z2_BIT |
585			AD7879_Z1_BIT |
586			AD7879_TEMPMASK_BIT |
587			AD7879_AUXVBATMASK_BIT |
588			AD7879_GPIOALERTMASK_BIT;
589
590	ts->cmd_crtl2 = AD7879_PM(AD7879_PM_DYN) | AD7879_DFR |
591			AD7879_AVG(ts->averaging) |
592			AD7879_MFS(ts->median) |
593			AD7879_FCD(ts->first_conversion_delay);
594
595	ts->cmd_crtl1 = AD7879_MODE_INT | AD7879_MODE_SEQ1 |
596			AD7879_ACQ(ts->acquisition_time) |
597			AD7879_TMR(ts->pen_down_acc_interval);
598
599	err = request_threaded_irq(ts->irq, NULL, ad7879_irq,
600				   IRQF_TRIGGER_FALLING,
601				   dev_name(dev), ts);
602	if (err) {
603		dev_err(dev, "irq %d busy?\n", ts->irq);
604		goto err_free_mem;
605	}
606
607	__ad7879_disable(ts);
608
609	err = sysfs_create_group(&dev->kobj, &ad7879_attr_group);
610	if (err)
611		goto err_free_irq;
612
613	err = ad7879_gpio_add(ts, pdata);
614	if (err)
615		goto err_remove_attr;
616
617	err = input_register_device(input_dev);
618	if (err)
619		goto err_remove_gpio;
620
621	return ts;
622
623err_remove_gpio:
624	ad7879_gpio_remove(ts);
625err_remove_attr:
626	sysfs_remove_group(&dev->kobj, &ad7879_attr_group);
627err_free_irq:
628	free_irq(ts->irq, ts);
629err_free_mem:
630	input_free_device(input_dev);
631	kfree(ts);
632err_out:
633	return ERR_PTR(err);
634}
635EXPORT_SYMBOL(ad7879_probe);
636
637void ad7879_remove(struct ad7879 *ts)
638{
639	ad7879_gpio_remove(ts);
640	sysfs_remove_group(&ts->dev->kobj, &ad7879_attr_group);
641	free_irq(ts->irq, ts);
642	input_unregister_device(ts->input);
643	kfree(ts);
644}
645EXPORT_SYMBOL(ad7879_remove);
646
647MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
648MODULE_DESCRIPTION("AD7879(-1) touchscreen Driver");
649MODULE_LICENSE("GPL");
650