xref: /openbmc/linux/drivers/mfd/ucb1x00-ts.c (revision 2c684d89)
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 
41 struct 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 
55 static int adcsync;
56 
57 static 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 
68 static 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  */
80 static 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  */
92 static 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  */
119 static 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  */
146 static 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  */
172 static 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  */
184 static 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 
192 static 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  */
207 static 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  */
291 static 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 
304 static 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  */
350 static 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  */
367 static 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 
419 static 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 
427 static struct ucb1x00_driver ucb1x00_ts_driver = {
428 	.add		= ucb1x00_ts_add,
429 	.remove		= ucb1x00_ts_remove,
430 };
431 
432 static int __init ucb1x00_ts_init(void)
433 {
434 	return ucb1x00_register_driver(&ucb1x00_ts_driver);
435 }
436 
437 static void __exit ucb1x00_ts_exit(void)
438 {
439 	ucb1x00_unregister_driver(&ucb1x00_ts_driver);
440 }
441 
442 module_param(adcsync, int, 0444);
443 module_init(ucb1x00_ts_init);
444 module_exit(ucb1x00_ts_exit);
445 
446 MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
447 MODULE_DESCRIPTION("UCB1x00 touchscreen driver");
448 MODULE_LICENSE("GPL");
449