1/*
2 *  Touchscreen driver for UCB1x00-based touchscreens
3 *
4 *  Copyright (C) 2001 Russell King, All Rights Reserved.
5 *  Copyright (C) 2005 Pavel Machek
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * 21-Jan-2002 <jco@ict.es> :
12 *
13 * Added support for synchronous A/D mode. This mode is useful to
14 * avoid noise induced in the touchpanel by the LCD, provided that
15 * the UCB1x00 has a valid LCD sync signal routed to its ADCSYNC pin.
16 * It is important to note that the signal connected to the ADCSYNC
17 * pin should provide pulses even when the LCD is blanked, otherwise
18 * a pen touch needed to unblank the LCD will never be read.
19 */
20#include <linux/module.h>
21#include <linux/moduleparam.h>
22#include <linux/init.h>
23#include <linux/interrupt.h>
24#include <linux/sched.h>
25#include <linux/spinlock.h>
26#include <linux/completion.h>
27#include <linux/delay.h>
28#include <linux/string.h>
29#include <linux/input.h>
30#include <linux/device.h>
31#include <linux/freezer.h>
32#include <linux/slab.h>
33#include <linux/kthread.h>
34#include <linux/mfd/ucb1x00.h>
35
36#include <mach/collie.h>
37#include <asm/mach-types.h>
38
39
40
41struct ucb1x00_ts {
42	struct input_dev	*idev;
43	struct ucb1x00		*ucb;
44
45	spinlock_t		irq_lock;
46	unsigned		irq_disabled;
47	wait_queue_head_t	irq_wait;
48	struct task_struct	*rtask;
49	u16			x_res;
50	u16			y_res;
51
52	unsigned int		adcsync:1;
53};
54
55static int adcsync;
56
57static inline void ucb1x00_ts_evt_add(struct ucb1x00_ts *ts, u16 pressure, u16 x, u16 y)
58{
59	struct input_dev *idev = ts->idev;
60
61	input_report_abs(idev, ABS_X, x);
62	input_report_abs(idev, ABS_Y, y);
63	input_report_abs(idev, ABS_PRESSURE, pressure);
64	input_report_key(idev, BTN_TOUCH, 1);
65	input_sync(idev);
66}
67
68static inline void ucb1x00_ts_event_release(struct ucb1x00_ts *ts)
69{
70	struct input_dev *idev = ts->idev;
71
72	input_report_abs(idev, ABS_PRESSURE, 0);
73	input_report_key(idev, BTN_TOUCH, 0);
74	input_sync(idev);
75}
76
77/*
78 * Switch to interrupt mode.
79 */
80static inline void ucb1x00_ts_mode_int(struct ucb1x00_ts *ts)
81{
82	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
83			UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
84			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
85			UCB_TS_CR_MODE_INT);
86}
87
88/*
89 * Switch to pressure mode, and read pressure.  We don't need to wait
90 * here, since both plates are being driven.
91 */
92static inline unsigned int ucb1x00_ts_read_pressure(struct ucb1x00_ts *ts)
93{
94	if (machine_is_collie()) {
95		ucb1x00_io_write(ts->ucb, COLLIE_TC35143_GPIO_TBL_CHK, 0);
96		ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
97				  UCB_TS_CR_TSPX_POW | UCB_TS_CR_TSMX_POW |
98				  UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
99
100		udelay(55);
101
102		return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_AD2, ts->adcsync);
103	} else {
104		ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
105				  UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
106				  UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
107				  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
108
109		return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPY, ts->adcsync);
110	}
111}
112
113/*
114 * Switch to X position mode and measure Y plate.  We switch the plate
115 * configuration in pressure mode, then switch to position mode.  This
116 * gives a faster response time.  Even so, we need to wait about 55us
117 * for things to stabilise.
118 */
119static inline unsigned int ucb1x00_ts_read_xpos(struct ucb1x00_ts *ts)
120{
121	if (machine_is_collie())
122		ucb1x00_io_write(ts->ucb, 0, COLLIE_TC35143_GPIO_TBL_CHK);
123	else {
124		ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
125				  UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
126				  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
127		ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
128				  UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
129				  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
130	}
131	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
132			UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
133			UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
134
135	udelay(55);
136
137	return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPY, ts->adcsync);
138}
139
140/*
141 * Switch to Y position mode and measure X plate.  We switch the plate
142 * configuration in pressure mode, then switch to position mode.  This
143 * gives a faster response time.  Even so, we need to wait about 55us
144 * for things to stabilise.
145 */
146static inline unsigned int ucb1x00_ts_read_ypos(struct ucb1x00_ts *ts)
147{
148	if (machine_is_collie())
149		ucb1x00_io_write(ts->ucb, 0, COLLIE_TC35143_GPIO_TBL_CHK);
150	else {
151		ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
152				  UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
153				  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
154		ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
155				  UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
156				  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
157	}
158
159	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
160			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
161			UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
162
163	udelay(55);
164
165	return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPX, ts->adcsync);
166}
167
168/*
169 * Switch to X plate resistance mode.  Set MX to ground, PX to
170 * supply.  Measure current.
171 */
172static inline unsigned int ucb1x00_ts_read_xres(struct ucb1x00_ts *ts)
173{
174	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
175			UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
176			UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
177	return ucb1x00_adc_read(ts->ucb, 0, ts->adcsync);
178}
179
180/*
181 * Switch to Y plate resistance mode.  Set MY to ground, PY to
182 * supply.  Measure current.
183 */
184static inline unsigned int ucb1x00_ts_read_yres(struct ucb1x00_ts *ts)
185{
186	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
187			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
188			UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
189	return ucb1x00_adc_read(ts->ucb, 0, ts->adcsync);
190}
191
192static inline int ucb1x00_ts_pen_down(struct ucb1x00_ts *ts)
193{
194	unsigned int val = ucb1x00_reg_read(ts->ucb, UCB_TS_CR);
195
196	if (machine_is_collie())
197		return (!(val & (UCB_TS_CR_TSPX_LOW)));
198	else
199		return (val & (UCB_TS_CR_TSPX_LOW | UCB_TS_CR_TSMX_LOW));
200}
201
202/*
203 * This is a RT kernel thread that handles the ADC accesses
204 * (mainly so we can use semaphores in the UCB1200 core code
205 * to serialise accesses to the ADC).
206 */
207static int ucb1x00_thread(void *_ts)
208{
209	struct ucb1x00_ts *ts = _ts;
210	DECLARE_WAITQUEUE(wait, current);
211	bool frozen, ignore = false;
212	int valid = 0;
213
214	set_freezable();
215	add_wait_queue(&ts->irq_wait, &wait);
216	while (!kthread_freezable_should_stop(&frozen)) {
217		unsigned int x, y, p;
218		signed long timeout;
219
220		if (frozen)
221			ignore = true;
222
223		ucb1x00_adc_enable(ts->ucb);
224
225		x = ucb1x00_ts_read_xpos(ts);
226		y = ucb1x00_ts_read_ypos(ts);
227		p = ucb1x00_ts_read_pressure(ts);
228
229		/*
230		 * Switch back to interrupt mode.
231		 */
232		ucb1x00_ts_mode_int(ts);
233		ucb1x00_adc_disable(ts->ucb);
234
235		msleep(10);
236
237		ucb1x00_enable(ts->ucb);
238
239
240		if (ucb1x00_ts_pen_down(ts)) {
241			set_current_state(TASK_INTERRUPTIBLE);
242
243			spin_lock_irq(&ts->irq_lock);
244			if (ts->irq_disabled) {
245				ts->irq_disabled = 0;
246				enable_irq(ts->ucb->irq_base + UCB_IRQ_TSPX);
247			}
248			spin_unlock_irq(&ts->irq_lock);
249			ucb1x00_disable(ts->ucb);
250
251			/*
252			 * If we spat out a valid sample set last time,
253			 * spit out a "pen off" sample here.
254			 */
255			if (valid) {
256				ucb1x00_ts_event_release(ts);
257				valid = 0;
258			}
259
260			timeout = MAX_SCHEDULE_TIMEOUT;
261		} else {
262			ucb1x00_disable(ts->ucb);
263
264			/*
265			 * Filtering is policy.  Policy belongs in user
266			 * space.  We therefore leave it to user space
267			 * to do any filtering they please.
268			 */
269			if (!ignore) {
270				ucb1x00_ts_evt_add(ts, p, x, y);
271				valid = 1;
272			}
273
274			set_current_state(TASK_INTERRUPTIBLE);
275			timeout = HZ / 100;
276		}
277
278		schedule_timeout(timeout);
279	}
280
281	remove_wait_queue(&ts->irq_wait, &wait);
282
283	ts->rtask = NULL;
284	return 0;
285}
286
287/*
288 * We only detect touch screen _touches_ with this interrupt
289 * handler, and even then we just schedule our task.
290 */
291static irqreturn_t ucb1x00_ts_irq(int irq, void *id)
292{
293	struct ucb1x00_ts *ts = id;
294
295	spin_lock(&ts->irq_lock);
296	ts->irq_disabled = 1;
297	disable_irq_nosync(ts->ucb->irq_base + UCB_IRQ_TSPX);
298	spin_unlock(&ts->irq_lock);
299	wake_up(&ts->irq_wait);
300
301	return IRQ_HANDLED;
302}
303
304static int ucb1x00_ts_open(struct input_dev *idev)
305{
306	struct ucb1x00_ts *ts = input_get_drvdata(idev);
307	unsigned long flags = 0;
308	int ret = 0;
309
310	BUG_ON(ts->rtask);
311
312	if (machine_is_collie())
313		flags = IRQF_TRIGGER_RISING;
314	else
315		flags = IRQF_TRIGGER_FALLING;
316
317	ts->irq_disabled = 0;
318
319	init_waitqueue_head(&ts->irq_wait);
320	ret = request_irq(ts->ucb->irq_base + UCB_IRQ_TSPX, ucb1x00_ts_irq,
321			  flags, "ucb1x00-ts", ts);
322	if (ret < 0)
323		goto out;
324
325	/*
326	 * If we do this at all, we should allow the user to
327	 * measure and read the X and Y resistance at any time.
328	 */
329	ucb1x00_adc_enable(ts->ucb);
330	ts->x_res = ucb1x00_ts_read_xres(ts);
331	ts->y_res = ucb1x00_ts_read_yres(ts);
332	ucb1x00_adc_disable(ts->ucb);
333
334	ts->rtask = kthread_run(ucb1x00_thread, ts, "ktsd");
335	if (!IS_ERR(ts->rtask)) {
336		ret = 0;
337	} else {
338		free_irq(ts->ucb->irq_base + UCB_IRQ_TSPX, ts);
339		ts->rtask = NULL;
340		ret = -EFAULT;
341	}
342
343 out:
344	return ret;
345}
346
347/*
348 * Release touchscreen resources.  Disable IRQs.
349 */
350static void ucb1x00_ts_close(struct input_dev *idev)
351{
352	struct ucb1x00_ts *ts = input_get_drvdata(idev);
353
354	if (ts->rtask)
355		kthread_stop(ts->rtask);
356
357	ucb1x00_enable(ts->ucb);
358	free_irq(ts->ucb->irq_base + UCB_IRQ_TSPX, ts);
359	ucb1x00_reg_write(ts->ucb, UCB_TS_CR, 0);
360	ucb1x00_disable(ts->ucb);
361}
362
363
364/*
365 * Initialisation.
366 */
367static int ucb1x00_ts_add(struct ucb1x00_dev *dev)
368{
369	struct ucb1x00_ts *ts;
370	struct input_dev *idev;
371	int err;
372
373	ts = kzalloc(sizeof(struct ucb1x00_ts), GFP_KERNEL);
374	idev = input_allocate_device();
375	if (!ts || !idev) {
376		err = -ENOMEM;
377		goto fail;
378	}
379
380	ts->ucb = dev->ucb;
381	ts->idev = idev;
382	ts->adcsync = adcsync ? UCB_SYNC : UCB_NOSYNC;
383	spin_lock_init(&ts->irq_lock);
384
385	idev->name       = "Touchscreen panel";
386	idev->id.product = ts->ucb->id;
387	idev->open       = ucb1x00_ts_open;
388	idev->close      = ucb1x00_ts_close;
389	idev->dev.parent = &ts->ucb->dev;
390
391	idev->evbit[0]   = BIT_MASK(EV_ABS) | BIT_MASK(EV_KEY);
392	idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
393
394	input_set_drvdata(idev, ts);
395
396	ucb1x00_adc_enable(ts->ucb);
397	ts->x_res = ucb1x00_ts_read_xres(ts);
398	ts->y_res = ucb1x00_ts_read_yres(ts);
399	ucb1x00_adc_disable(ts->ucb);
400
401	input_set_abs_params(idev, ABS_X, 0, ts->x_res, 0, 0);
402	input_set_abs_params(idev, ABS_Y, 0, ts->y_res, 0, 0);
403	input_set_abs_params(idev, ABS_PRESSURE, 0, 0, 0, 0);
404
405	err = input_register_device(idev);
406	if (err)
407		goto fail;
408
409	dev->priv = ts;
410
411	return 0;
412
413 fail:
414	input_free_device(idev);
415	kfree(ts);
416	return err;
417}
418
419static void ucb1x00_ts_remove(struct ucb1x00_dev *dev)
420{
421	struct ucb1x00_ts *ts = dev->priv;
422
423	input_unregister_device(ts->idev);
424	kfree(ts);
425}
426
427static struct ucb1x00_driver ucb1x00_ts_driver = {
428	.add		= ucb1x00_ts_add,
429	.remove		= ucb1x00_ts_remove,
430};
431
432static int __init ucb1x00_ts_init(void)
433{
434	return ucb1x00_register_driver(&ucb1x00_ts_driver);
435}
436
437static void __exit ucb1x00_ts_exit(void)
438{
439	ucb1x00_unregister_driver(&ucb1x00_ts_driver);
440}
441
442module_param(adcsync, int, 0444);
443module_init(ucb1x00_ts_init);
444module_exit(ucb1x00_ts_exit);
445
446MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
447MODULE_DESCRIPTION("UCB1x00 touchscreen driver");
448MODULE_LICENSE("GPL");
449