xref: /linux/drivers/mfd/ucb1x00-ts.c (revision 75bf465f0bc33e9b776a46d6a1b9b990f5fb7c37)
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 
38 struct 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 
52 static int adcsync;
53 
ucb1x00_ts_evt_add(struct ucb1x00_ts * ts,u16 pressure,u16 x,u16 y)54 static 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 
ucb1x00_ts_event_release(struct ucb1x00_ts * ts)65 static 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  */
ucb1x00_ts_mode_int(struct ucb1x00_ts * ts)77 static 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  */
ucb1x00_ts_read_pressure(struct ucb1x00_ts * ts)89 static 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  */
ucb1x00_ts_read_xpos(struct ucb1x00_ts * ts)116 static 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  */
ucb1x00_ts_read_ypos(struct ucb1x00_ts * ts)143 static 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  */
ucb1x00_ts_read_xres(struct ucb1x00_ts * ts)169 static 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  */
ucb1x00_ts_read_yres(struct ucb1x00_ts * ts)181 static 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 
ucb1x00_ts_pen_down(struct ucb1x00_ts * ts)189 static 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  */
ucb1x00_thread(void * _ts)204 static 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  */
ucb1x00_ts_irq(int irq,void * id)288 static 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 
ucb1x00_ts_open(struct input_dev * idev)301 static 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  */
ucb1x00_ts_close(struct input_dev * idev)347 static 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  */
ucb1x00_ts_add(struct ucb1x00_dev * dev)364 static 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 
ucb1x00_ts_remove(struct ucb1x00_dev * dev)416 static 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 
424 static struct ucb1x00_driver ucb1x00_ts_driver = {
425 	.add		= ucb1x00_ts_add,
426 	.remove		= ucb1x00_ts_remove,
427 };
428 
ucb1x00_ts_init(void)429 static int __init ucb1x00_ts_init(void)
430 {
431 	return ucb1x00_register_driver(&ucb1x00_ts_driver);
432 }
433 
ucb1x00_ts_exit(void)434 static void __exit ucb1x00_ts_exit(void)
435 {
436 	ucb1x00_unregister_driver(&ucb1x00_ts_driver);
437 }
438 
439 module_param(adcsync, int, 0444);
440 module_init(ucb1x00_ts_init);
441 module_exit(ucb1x00_ts_exit);
442 
443 MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
444 MODULE_DESCRIPTION("UCB1x00 touchscreen driver");
445 MODULE_LICENSE("GPL");
446