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/drivers/mfd/ucb1x00-ts.c

http://github.com/mirrors/linux
C | 445 lines | 292 code | 79 blank | 74 comment | 22 complexity | 0bc34466c3c5353b7e7357893ef184cb MD5 | raw file
  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 *  Touchscreen driver for UCB1x00-based touchscreens
  4 *
  5 *  Copyright (C) 2001 Russell King, All Rights Reserved.
  6 *  Copyright (C) 2005 Pavel Machek
  7 *
  8 * 21-Jan-2002 <jco@ict.es> :
  9 *
 10 * Added support for synchronous A/D mode. This mode is useful to
 11 * avoid noise induced in the touchpanel by the LCD, provided that
 12 * the UCB1x00 has a valid LCD sync signal routed to its ADCSYNC pin.
 13 * It is important to note that the signal connected to the ADCSYNC
 14 * pin should provide pulses even when the LCD is blanked, otherwise
 15 * a pen touch needed to unblank the LCD will never be read.
 16 */
 17#include <linux/module.h>
 18#include <linux/moduleparam.h>
 19#include <linux/init.h>
 20#include <linux/interrupt.h>
 21#include <linux/sched.h>
 22#include <linux/spinlock.h>
 23#include <linux/completion.h>
 24#include <linux/delay.h>
 25#include <linux/string.h>
 26#include <linux/input.h>
 27#include <linux/device.h>
 28#include <linux/freezer.h>
 29#include <linux/slab.h>
 30#include <linux/kthread.h>
 31#include <linux/mfd/ucb1x00.h>
 32
 33#include <mach/collie.h>
 34#include <asm/mach-types.h>
 35
 36
 37
 38struct ucb1x00_ts {
 39	struct input_dev	*idev;
 40	struct ucb1x00		*ucb;
 41
 42	spinlock_t		irq_lock;
 43	unsigned		irq_disabled;
 44	wait_queue_head_t	irq_wait;
 45	struct task_struct	*rtask;
 46	u16			x_res;
 47	u16			y_res;
 48
 49	unsigned int		adcsync:1;
 50};
 51
 52static int adcsync;
 53
 54static inline void ucb1x00_ts_evt_add(struct ucb1x00_ts *ts, u16 pressure, u16 x, u16 y)
 55{
 56	struct input_dev *idev = ts->idev;
 57
 58	input_report_abs(idev, ABS_X, x);
 59	input_report_abs(idev, ABS_Y, y);
 60	input_report_abs(idev, ABS_PRESSURE, pressure);
 61	input_report_key(idev, BTN_TOUCH, 1);
 62	input_sync(idev);
 63}
 64
 65static inline void ucb1x00_ts_event_release(struct ucb1x00_ts *ts)
 66{
 67	struct input_dev *idev = ts->idev;
 68
 69	input_report_abs(idev, ABS_PRESSURE, 0);
 70	input_report_key(idev, BTN_TOUCH, 0);
 71	input_sync(idev);
 72}
 73
 74/*
 75 * Switch to interrupt mode.
 76 */
 77static inline void ucb1x00_ts_mode_int(struct ucb1x00_ts *ts)
 78{
 79	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 80			UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
 81			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
 82			UCB_TS_CR_MODE_INT);
 83}
 84
 85/*
 86 * Switch to pressure mode, and read pressure.  We don't need to wait
 87 * here, since both plates are being driven.
 88 */
 89static inline unsigned int ucb1x00_ts_read_pressure(struct ucb1x00_ts *ts)
 90{
 91	if (machine_is_collie()) {
 92		ucb1x00_io_write(ts->ucb, COLLIE_TC35143_GPIO_TBL_CHK, 0);
 93		ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
 94				  UCB_TS_CR_TSPX_POW | UCB_TS_CR_TSMX_POW |
 95				  UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
 96
 97		udelay(55);
 98
 99		return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_AD2, ts->adcsync);
100	} else {
101		ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
102				  UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
103				  UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
104				  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
105
106		return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPY, ts->adcsync);
107	}
108}
109
110/*
111 * Switch to X position mode and measure Y plate.  We switch the plate
112 * configuration in pressure mode, then switch to position mode.  This
113 * gives a faster response time.  Even so, we need to wait about 55us
114 * for things to stabilise.
115 */
116static inline unsigned int ucb1x00_ts_read_xpos(struct ucb1x00_ts *ts)
117{
118	if (machine_is_collie())
119		ucb1x00_io_write(ts->ucb, 0, COLLIE_TC35143_GPIO_TBL_CHK);
120	else {
121		ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
122				  UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
123				  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
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	}
128	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
129			UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
130			UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
131
132	udelay(55);
133
134	return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPY, ts->adcsync);
135}
136
137/*
138 * Switch to Y position mode and measure X plate.  We switch the plate
139 * configuration in pressure mode, then switch to position mode.  This
140 * gives a faster response time.  Even so, we need to wait about 55us
141 * for things to stabilise.
142 */
143static inline unsigned int ucb1x00_ts_read_ypos(struct ucb1x00_ts *ts)
144{
145	if (machine_is_collie())
146		ucb1x00_io_write(ts->ucb, 0, COLLIE_TC35143_GPIO_TBL_CHK);
147	else {
148		ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
149				  UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
150				  UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
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	}
155
156	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
157			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
158			UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
159
160	udelay(55);
161
162	return ucb1x00_adc_read(ts->ucb, UCB_ADC_INP_TSPX, ts->adcsync);
163}
164
165/*
166 * Switch to X plate resistance mode.  Set MX to ground, PX to
167 * supply.  Measure current.
168 */
169static inline unsigned int ucb1x00_ts_read_xres(struct ucb1x00_ts *ts)
170{
171	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
172			UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
173			UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
174	return ucb1x00_adc_read(ts->ucb, 0, ts->adcsync);
175}
176
177/*
178 * Switch to Y plate resistance mode.  Set MY to ground, PY to
179 * supply.  Measure current.
180 */
181static inline unsigned int ucb1x00_ts_read_yres(struct ucb1x00_ts *ts)
182{
183	ucb1x00_reg_write(ts->ucb, UCB_TS_CR,
184			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
185			UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
186	return ucb1x00_adc_read(ts->ucb, 0, ts->adcsync);
187}
188
189static inline int ucb1x00_ts_pen_down(struct ucb1x00_ts *ts)
190{
191	unsigned int val = ucb1x00_reg_read(ts->ucb, UCB_TS_CR);
192
193	if (machine_is_collie())
194		return (!(val & (UCB_TS_CR_TSPX_LOW)));
195	else
196		return (val & (UCB_TS_CR_TSPX_LOW | UCB_TS_CR_TSMX_LOW));
197}
198
199/*
200 * This is a RT kernel thread that handles the ADC accesses
201 * (mainly so we can use semaphores in the UCB1200 core code
202 * to serialise accesses to the ADC).
203 */
204static int ucb1x00_thread(void *_ts)
205{
206	struct ucb1x00_ts *ts = _ts;
207	DECLARE_WAITQUEUE(wait, current);
208	bool frozen, ignore = false;
209	int valid = 0;
210
211	set_freezable();
212	add_wait_queue(&ts->irq_wait, &wait);
213	while (!kthread_freezable_should_stop(&frozen)) {
214		unsigned int x, y, p;
215		signed long timeout;
216
217		if (frozen)
218			ignore = true;
219
220		ucb1x00_adc_enable(ts->ucb);
221
222		x = ucb1x00_ts_read_xpos(ts);
223		y = ucb1x00_ts_read_ypos(ts);
224		p = ucb1x00_ts_read_pressure(ts);
225
226		/*
227		 * Switch back to interrupt mode.
228		 */
229		ucb1x00_ts_mode_int(ts);
230		ucb1x00_adc_disable(ts->ucb);
231
232		msleep(10);
233
234		ucb1x00_enable(ts->ucb);
235
236
237		if (ucb1x00_ts_pen_down(ts)) {
238			set_current_state(TASK_INTERRUPTIBLE);
239
240			spin_lock_irq(&ts->irq_lock);
241			if (ts->irq_disabled) {
242				ts->irq_disabled = 0;
243				enable_irq(ts->ucb->irq_base + UCB_IRQ_TSPX);
244			}
245			spin_unlock_irq(&ts->irq_lock);
246			ucb1x00_disable(ts->ucb);
247
248			/*
249			 * If we spat out a valid sample set last time,
250			 * spit out a "pen off" sample here.
251			 */
252			if (valid) {
253				ucb1x00_ts_event_release(ts);
254				valid = 0;
255			}
256
257			timeout = MAX_SCHEDULE_TIMEOUT;
258		} else {
259			ucb1x00_disable(ts->ucb);
260
261			/*
262			 * Filtering is policy.  Policy belongs in user
263			 * space.  We therefore leave it to user space
264			 * to do any filtering they please.
265			 */
266			if (!ignore) {
267				ucb1x00_ts_evt_add(ts, p, x, y);
268				valid = 1;
269			}
270
271			set_current_state(TASK_INTERRUPTIBLE);
272			timeout = HZ / 100;
273		}
274
275		schedule_timeout(timeout);
276	}
277
278	remove_wait_queue(&ts->irq_wait, &wait);
279
280	ts->rtask = NULL;
281	return 0;
282}
283
284/*
285 * We only detect touch screen _touches_ with this interrupt
286 * handler, and even then we just schedule our task.
287 */
288static irqreturn_t ucb1x00_ts_irq(int irq, void *id)
289{
290	struct ucb1x00_ts *ts = id;
291
292	spin_lock(&ts->irq_lock);
293	ts->irq_disabled = 1;
294	disable_irq_nosync(ts->ucb->irq_base + UCB_IRQ_TSPX);
295	spin_unlock(&ts->irq_lock);
296	wake_up(&ts->irq_wait);
297
298	return IRQ_HANDLED;
299}
300
301static int ucb1x00_ts_open(struct input_dev *idev)
302{
303	struct ucb1x00_ts *ts = input_get_drvdata(idev);
304	unsigned long flags = 0;
305	int ret = 0;
306
307	BUG_ON(ts->rtask);
308
309	if (machine_is_collie())
310		flags = IRQF_TRIGGER_RISING;
311	else
312		flags = IRQF_TRIGGER_FALLING;
313
314	ts->irq_disabled = 0;
315
316	init_waitqueue_head(&ts->irq_wait);
317	ret = request_irq(ts->ucb->irq_base + UCB_IRQ_TSPX, ucb1x00_ts_irq,
318			  flags, "ucb1x00-ts", ts);
319	if (ret < 0)
320		goto out;
321
322	/*
323	 * If we do this at all, we should allow the user to
324	 * measure and read the X and Y resistance at any time.
325	 */
326	ucb1x00_adc_enable(ts->ucb);
327	ts->x_res = ucb1x00_ts_read_xres(ts);
328	ts->y_res = ucb1x00_ts_read_yres(ts);
329	ucb1x00_adc_disable(ts->ucb);
330
331	ts->rtask = kthread_run(ucb1x00_thread, ts, "ktsd");
332	if (!IS_ERR(ts->rtask)) {
333		ret = 0;
334	} else {
335		free_irq(ts->ucb->irq_base + UCB_IRQ_TSPX, ts);
336		ts->rtask = NULL;
337		ret = -EFAULT;
338	}
339
340 out:
341	return ret;
342}
343
344/*
345 * Release touchscreen resources.  Disable IRQs.
346 */
347static void ucb1x00_ts_close(struct input_dev *idev)
348{
349	struct ucb1x00_ts *ts = input_get_drvdata(idev);
350
351	if (ts->rtask)
352		kthread_stop(ts->rtask);
353
354	ucb1x00_enable(ts->ucb);
355	free_irq(ts->ucb->irq_base + UCB_IRQ_TSPX, ts);
356	ucb1x00_reg_write(ts->ucb, UCB_TS_CR, 0);
357	ucb1x00_disable(ts->ucb);
358}
359
360
361/*
362 * Initialisation.
363 */
364static int ucb1x00_ts_add(struct ucb1x00_dev *dev)
365{
366	struct ucb1x00_ts *ts;
367	struct input_dev *idev;
368	int err;
369
370	ts = kzalloc(sizeof(struct ucb1x00_ts), GFP_KERNEL);
371	idev = input_allocate_device();
372	if (!ts || !idev) {
373		err = -ENOMEM;
374		goto fail;
375	}
376
377	ts->ucb = dev->ucb;
378	ts->idev = idev;
379	ts->adcsync = adcsync ? UCB_SYNC : UCB_NOSYNC;
380	spin_lock_init(&ts->irq_lock);
381
382	idev->name       = "Touchscreen panel";
383	idev->id.product = ts->ucb->id;
384	idev->open       = ucb1x00_ts_open;
385	idev->close      = ucb1x00_ts_close;
386	idev->dev.parent = &ts->ucb->dev;
387
388	idev->evbit[0]   = BIT_MASK(EV_ABS) | BIT_MASK(EV_KEY);
389	idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
390
391	input_set_drvdata(idev, ts);
392
393	ucb1x00_adc_enable(ts->ucb);
394	ts->x_res = ucb1x00_ts_read_xres(ts);
395	ts->y_res = ucb1x00_ts_read_yres(ts);
396	ucb1x00_adc_disable(ts->ucb);
397
398	input_set_abs_params(idev, ABS_X, 0, ts->x_res, 0, 0);
399	input_set_abs_params(idev, ABS_Y, 0, ts->y_res, 0, 0);
400	input_set_abs_params(idev, ABS_PRESSURE, 0, 0, 0, 0);
401
402	err = input_register_device(idev);
403	if (err)
404		goto fail;
405
406	dev->priv = ts;
407
408	return 0;
409
410 fail:
411	input_free_device(idev);
412	kfree(ts);
413	return err;
414}
415
416static void ucb1x00_ts_remove(struct ucb1x00_dev *dev)
417{
418	struct ucb1x00_ts *ts = dev->priv;
419
420	input_unregister_device(ts->idev);
421	kfree(ts);
422}
423
424static struct ucb1x00_driver ucb1x00_ts_driver = {
425	.add		= ucb1x00_ts_add,
426	.remove		= ucb1x00_ts_remove,
427};
428
429static int __init ucb1x00_ts_init(void)
430{
431	return ucb1x00_register_driver(&ucb1x00_ts_driver);
432}
433
434static void __exit ucb1x00_ts_exit(void)
435{
436	ucb1x00_unregister_driver(&ucb1x00_ts_driver);
437}
438
439module_param(adcsync, int, 0444);
440module_init(ucb1x00_ts_init);
441module_exit(ucb1x00_ts_exit);
442
443MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
444MODULE_DESCRIPTION("UCB1x00 touchscreen driver");
445MODULE_LICENSE("GPL");