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1 /*
2  *  Philips UCB1400 touchscreen driver
3  *
4  *  Author:	Nicolas Pitre
5  *  Created:	September 25, 2006
6  *  Copyright:	MontaVista Software, Inc.
7  *
8  * Spliting done by: Marek Vasut <marek.vasut@gmail.com>
9  * If something doesnt work and it worked before spliting, e-mail me,
10  * dont bother Nicolas please ;-)
11  *
12  * This program is free software; you can redistribute it and/or modify
13  * it under the terms of the GNU General Public License version 2 as
14  * published by the Free Software Foundation.
15  *
16  * This code is heavily based on ucb1x00-*.c copyrighted by Russell King
17  * covering the UCB1100, UCB1200 and UCB1300..  Support for the UCB1400 has
18  * been made separate from ucb1x00-core/ucb1x00-ts on Russell's request.
19  */
20 
21 #include <linux/module.h>
22 #include <linux/init.h>
23 #include <linux/completion.h>
24 #include <linux/delay.h>
25 #include <linux/input.h>
26 #include <linux/device.h>
27 #include <linux/interrupt.h>
28 #include <linux/suspend.h>
29 #include <linux/slab.h>
30 #include <linux/kthread.h>
31 #include <linux/freezer.h>
32 #include <linux/ucb1400.h>
33 
34 static int adcsync;
35 static int ts_delay = 55; /* us */
36 static int ts_delay_pressure;	/* us */
37 
38 /* Switch to interrupt mode. */
ucb1400_ts_mode_int(struct snd_ac97 * ac97)39 static inline void ucb1400_ts_mode_int(struct snd_ac97 *ac97)
40 {
41 	ucb1400_reg_write(ac97, UCB_TS_CR,
42 			UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
43 			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
44 			UCB_TS_CR_MODE_INT);
45 }
46 
47 /*
48  * Switch to pressure mode, and read pressure.  We don't need to wait
49  * here, since both plates are being driven.
50  */
ucb1400_ts_read_pressure(struct ucb1400_ts * ucb)51 static inline unsigned int ucb1400_ts_read_pressure(struct ucb1400_ts *ucb)
52 {
53 	ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
54 			UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
55 			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
56 			UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
57 	udelay(ts_delay_pressure);
58 	return ucb1400_adc_read(ucb->ac97, UCB_ADC_INP_TSPY, adcsync);
59 }
60 
61 /*
62  * Switch to X position mode and measure Y plate.  We switch the plate
63  * configuration in pressure mode, then switch to position mode.  This
64  * gives a faster response time.  Even so, we need to wait about 55us
65  * for things to stabilise.
66  */
ucb1400_ts_read_xpos(struct ucb1400_ts * ucb)67 static inline unsigned int ucb1400_ts_read_xpos(struct ucb1400_ts *ucb)
68 {
69 	ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
70 			UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
71 			UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
72 	ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
73 			UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
74 			UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
75 	ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
76 			UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
77 			UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
78 
79 	udelay(ts_delay);
80 
81 	return ucb1400_adc_read(ucb->ac97, UCB_ADC_INP_TSPY, adcsync);
82 }
83 
84 /*
85  * Switch to Y position mode and measure X plate.  We switch the plate
86  * configuration in pressure mode, then switch to position mode.  This
87  * gives a faster response time.  Even so, we need to wait about 55us
88  * for things to stabilise.
89  */
ucb1400_ts_read_ypos(struct ucb1400_ts * ucb)90 static inline unsigned int ucb1400_ts_read_ypos(struct ucb1400_ts *ucb)
91 {
92 	ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
93 			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
94 			UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
95 	ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
96 			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
97 			UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
98 	ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
99 			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
100 			UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);
101 
102 	udelay(ts_delay);
103 
104 	return ucb1400_adc_read(ucb->ac97, UCB_ADC_INP_TSPX, adcsync);
105 }
106 
107 /*
108  * Switch to X plate resistance mode.  Set MX to ground, PX to
109  * supply.  Measure current.
110  */
ucb1400_ts_read_xres(struct ucb1400_ts * ucb)111 static inline unsigned int ucb1400_ts_read_xres(struct ucb1400_ts *ucb)
112 {
113 	ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
114 			UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
115 			UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
116 	return ucb1400_adc_read(ucb->ac97, 0, adcsync);
117 }
118 
119 /*
120  * Switch to Y plate resistance mode.  Set MY to ground, PY to
121  * supply.  Measure current.
122  */
ucb1400_ts_read_yres(struct ucb1400_ts * ucb)123 static inline unsigned int ucb1400_ts_read_yres(struct ucb1400_ts *ucb)
124 {
125 	ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
126 			UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
127 			UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
128 	return ucb1400_adc_read(ucb->ac97, 0, adcsync);
129 }
130 
ucb1400_ts_pen_down(struct snd_ac97 * ac97)131 static inline int ucb1400_ts_pen_down(struct snd_ac97 *ac97)
132 {
133 	unsigned short val = ucb1400_reg_read(ac97, UCB_TS_CR);
134 	return val & (UCB_TS_CR_TSPX_LOW | UCB_TS_CR_TSMX_LOW);
135 }
136 
ucb1400_ts_irq_enable(struct snd_ac97 * ac97)137 static inline void ucb1400_ts_irq_enable(struct snd_ac97 *ac97)
138 {
139 	ucb1400_reg_write(ac97, UCB_IE_CLEAR, UCB_IE_TSPX);
140 	ucb1400_reg_write(ac97, UCB_IE_CLEAR, 0);
141 	ucb1400_reg_write(ac97, UCB_IE_FAL, UCB_IE_TSPX);
142 }
143 
ucb1400_ts_irq_disable(struct snd_ac97 * ac97)144 static inline void ucb1400_ts_irq_disable(struct snd_ac97 *ac97)
145 {
146 	ucb1400_reg_write(ac97, UCB_IE_FAL, 0);
147 }
148 
ucb1400_ts_evt_add(struct input_dev * idev,u16 pressure,u16 x,u16 y)149 static void ucb1400_ts_evt_add(struct input_dev *idev, u16 pressure, u16 x, u16 y)
150 {
151 	input_report_abs(idev, ABS_X, x);
152 	input_report_abs(idev, ABS_Y, y);
153 	input_report_abs(idev, ABS_PRESSURE, pressure);
154 	input_sync(idev);
155 }
156 
ucb1400_ts_event_release(struct input_dev * idev)157 static void ucb1400_ts_event_release(struct input_dev *idev)
158 {
159 	input_report_abs(idev, ABS_PRESSURE, 0);
160 	input_sync(idev);
161 }
162 
ucb1400_handle_pending_irq(struct ucb1400_ts * ucb)163 static void ucb1400_handle_pending_irq(struct ucb1400_ts *ucb)
164 {
165 	unsigned int isr;
166 
167 	isr = ucb1400_reg_read(ucb->ac97, UCB_IE_STATUS);
168 	ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, isr);
169 	ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0);
170 
171 	if (isr & UCB_IE_TSPX) {
172 		ucb1400_ts_irq_disable(ucb->ac97);
173 		enable_irq(ucb->irq);
174 	} else
175 		printk(KERN_ERR "ucb1400: unexpected IE_STATUS = %#x\n", isr);
176 }
177 
ucb1400_ts_thread(void * _ucb)178 static int ucb1400_ts_thread(void *_ucb)
179 {
180 	struct ucb1400_ts *ucb = _ucb;
181 	struct task_struct *tsk = current;
182 	int valid = 0;
183 	struct sched_param param = { .sched_priority = 1 };
184 
185 	sched_setscheduler(tsk, SCHED_FIFO, &param);
186 
187 	set_freezable();
188 	while (!kthread_should_stop()) {
189 		unsigned int x, y, p;
190 		long timeout;
191 
192 		ucb->ts_restart = 0;
193 
194 		if (ucb->irq_pending) {
195 			ucb->irq_pending = 0;
196 			ucb1400_handle_pending_irq(ucb);
197 		}
198 
199 		ucb1400_adc_enable(ucb->ac97);
200 		x = ucb1400_ts_read_xpos(ucb);
201 		y = ucb1400_ts_read_ypos(ucb);
202 		p = ucb1400_ts_read_pressure(ucb);
203 		ucb1400_adc_disable(ucb->ac97);
204 
205 		/* Switch back to interrupt mode. */
206 		ucb1400_ts_mode_int(ucb->ac97);
207 
208 		msleep(10);
209 
210 		if (ucb1400_ts_pen_down(ucb->ac97)) {
211 			ucb1400_ts_irq_enable(ucb->ac97);
212 
213 			/*
214 			 * If we spat out a valid sample set last time,
215 			 * spit out a "pen off" sample here.
216 			 */
217 			if (valid) {
218 				ucb1400_ts_event_release(ucb->ts_idev);
219 				valid = 0;
220 			}
221 
222 			timeout = MAX_SCHEDULE_TIMEOUT;
223 		} else {
224 			valid = 1;
225 			ucb1400_ts_evt_add(ucb->ts_idev, p, x, y);
226 			timeout = msecs_to_jiffies(10);
227 		}
228 
229 		wait_event_freezable_timeout(ucb->ts_wait,
230 			ucb->irq_pending || ucb->ts_restart ||
231 			kthread_should_stop(), timeout);
232 	}
233 
234 	/* Send the "pen off" if we are stopping with the pen still active */
235 	if (valid)
236 		ucb1400_ts_event_release(ucb->ts_idev);
237 
238 	ucb->ts_task = NULL;
239 	return 0;
240 }
241 
242 /*
243  * A restriction with interrupts exists when using the ucb1400, as
244  * the codec read/write routines may sleep while waiting for codec
245  * access completion and uses semaphores for access control to the
246  * AC97 bus.  A complete codec read cycle could take  anywhere from
247  * 60 to 100uSec so we *definitely* don't want to spin inside the
248  * interrupt handler waiting for codec access.  So, we handle the
249  * interrupt by scheduling a RT kernel thread to run in process
250  * context instead of interrupt context.
251  */
ucb1400_hard_irq(int irqnr,void * devid)252 static irqreturn_t ucb1400_hard_irq(int irqnr, void *devid)
253 {
254 	struct ucb1400_ts *ucb = devid;
255 
256 	if (irqnr == ucb->irq) {
257 		disable_irq(ucb->irq);
258 		ucb->irq_pending = 1;
259 		wake_up(&ucb->ts_wait);
260 		return IRQ_HANDLED;
261 	}
262 	return IRQ_NONE;
263 }
264 
ucb1400_ts_open(struct input_dev * idev)265 static int ucb1400_ts_open(struct input_dev *idev)
266 {
267 	struct ucb1400_ts *ucb = input_get_drvdata(idev);
268 	int ret = 0;
269 
270 	BUG_ON(ucb->ts_task);
271 
272 	ucb->ts_task = kthread_run(ucb1400_ts_thread, ucb, "UCB1400_ts");
273 	if (IS_ERR(ucb->ts_task)) {
274 		ret = PTR_ERR(ucb->ts_task);
275 		ucb->ts_task = NULL;
276 	}
277 
278 	return ret;
279 }
280 
ucb1400_ts_close(struct input_dev * idev)281 static void ucb1400_ts_close(struct input_dev *idev)
282 {
283 	struct ucb1400_ts *ucb = input_get_drvdata(idev);
284 
285 	if (ucb->ts_task)
286 		kthread_stop(ucb->ts_task);
287 
288 	ucb1400_ts_irq_disable(ucb->ac97);
289 	ucb1400_reg_write(ucb->ac97, UCB_TS_CR, 0);
290 }
291 
292 #ifndef NO_IRQ
293 #define NO_IRQ	0
294 #endif
295 
296 /*
297  * Try to probe our interrupt, rather than relying on lots of
298  * hard-coded machine dependencies.
299  */
ucb1400_ts_detect_irq(struct ucb1400_ts * ucb)300 static int ucb1400_ts_detect_irq(struct ucb1400_ts *ucb)
301 {
302 	unsigned long mask, timeout;
303 
304 	mask = probe_irq_on();
305 
306 	/* Enable the ADC interrupt. */
307 	ucb1400_reg_write(ucb->ac97, UCB_IE_RIS, UCB_IE_ADC);
308 	ucb1400_reg_write(ucb->ac97, UCB_IE_FAL, UCB_IE_ADC);
309 	ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0xffff);
310 	ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0);
311 
312 	/* Cause an ADC interrupt. */
313 	ucb1400_reg_write(ucb->ac97, UCB_ADC_CR, UCB_ADC_ENA);
314 	ucb1400_reg_write(ucb->ac97, UCB_ADC_CR, UCB_ADC_ENA | UCB_ADC_START);
315 
316 	/* Wait for the conversion to complete. */
317 	timeout = jiffies + HZ/2;
318 	while (!(ucb1400_reg_read(ucb->ac97, UCB_ADC_DATA) &
319 						UCB_ADC_DAT_VALID)) {
320 		cpu_relax();
321 		if (time_after(jiffies, timeout)) {
322 			printk(KERN_ERR "ucb1400: timed out in IRQ probe\n");
323 			probe_irq_off(mask);
324 			return -ENODEV;
325 		}
326 	}
327 	ucb1400_reg_write(ucb->ac97, UCB_ADC_CR, 0);
328 
329 	/* Disable and clear interrupt. */
330 	ucb1400_reg_write(ucb->ac97, UCB_IE_RIS, 0);
331 	ucb1400_reg_write(ucb->ac97, UCB_IE_FAL, 0);
332 	ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0xffff);
333 	ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0);
334 
335 	/* Read triggered interrupt. */
336 	ucb->irq = probe_irq_off(mask);
337 	if (ucb->irq < 0 || ucb->irq == NO_IRQ)
338 		return -ENODEV;
339 
340 	return 0;
341 }
342 
ucb1400_ts_probe(struct platform_device * dev)343 static int ucb1400_ts_probe(struct platform_device *dev)
344 {
345 	int error, x_res, y_res;
346 	struct ucb1400_ts *ucb = dev->dev.platform_data;
347 
348 	ucb->ts_idev = input_allocate_device();
349 	if (!ucb->ts_idev) {
350 		error = -ENOMEM;
351 		goto err;
352 	}
353 
354 	error = ucb1400_ts_detect_irq(ucb);
355 	if (error) {
356 		printk(KERN_ERR "UCB1400: IRQ probe failed\n");
357 		goto err_free_devs;
358 	}
359 
360 	init_waitqueue_head(&ucb->ts_wait);
361 
362 	error = request_irq(ucb->irq, ucb1400_hard_irq, IRQF_TRIGGER_RISING,
363 				"UCB1400", ucb);
364 	if (error) {
365 		printk(KERN_ERR "ucb1400: unable to grab irq%d: %d\n",
366 				ucb->irq, error);
367 		goto err_free_devs;
368 	}
369 	printk(KERN_DEBUG "UCB1400: found IRQ %d\n", ucb->irq);
370 
371 	input_set_drvdata(ucb->ts_idev, ucb);
372 
373 	ucb->ts_idev->dev.parent	= &dev->dev;
374 	ucb->ts_idev->name		= "UCB1400 touchscreen interface";
375 	ucb->ts_idev->id.vendor		= ucb1400_reg_read(ucb->ac97,
376 						AC97_VENDOR_ID1);
377 	ucb->ts_idev->id.product	= ucb->id;
378 	ucb->ts_idev->open		= ucb1400_ts_open;
379 	ucb->ts_idev->close		= ucb1400_ts_close;
380 	ucb->ts_idev->evbit[0]		= BIT_MASK(EV_ABS);
381 
382 	ucb1400_adc_enable(ucb->ac97);
383 	x_res = ucb1400_ts_read_xres(ucb);
384 	y_res = ucb1400_ts_read_yres(ucb);
385 	ucb1400_adc_disable(ucb->ac97);
386 	printk(KERN_DEBUG "UCB1400: x/y = %d/%d\n", x_res, y_res);
387 
388 	input_set_abs_params(ucb->ts_idev, ABS_X, 0, x_res, 0, 0);
389 	input_set_abs_params(ucb->ts_idev, ABS_Y, 0, y_res, 0, 0);
390 	input_set_abs_params(ucb->ts_idev, ABS_PRESSURE, 0, 0, 0, 0);
391 
392 	error = input_register_device(ucb->ts_idev);
393 	if (error)
394 		goto err_free_irq;
395 
396 	return 0;
397 
398 err_free_irq:
399 	free_irq(ucb->irq, ucb);
400 err_free_devs:
401 	input_free_device(ucb->ts_idev);
402 err:
403 	return error;
404 
405 }
406 
ucb1400_ts_remove(struct platform_device * dev)407 static int ucb1400_ts_remove(struct platform_device *dev)
408 {
409 	struct ucb1400_ts *ucb = dev->dev.platform_data;
410 
411 	free_irq(ucb->irq, ucb);
412 	input_unregister_device(ucb->ts_idev);
413 	return 0;
414 }
415 
416 #ifdef CONFIG_PM
ucb1400_ts_resume(struct platform_device * dev)417 static int ucb1400_ts_resume(struct platform_device *dev)
418 {
419 	struct ucb1400_ts *ucb = platform_get_drvdata(dev);
420 
421 	if (ucb->ts_task) {
422 		/*
423 		 * Restart the TS thread to ensure the
424 		 * TS interrupt mode is set up again
425 		 * after sleep.
426 		 */
427 		ucb->ts_restart = 1;
428 		wake_up(&ucb->ts_wait);
429 	}
430 	return 0;
431 }
432 #else
433 #define ucb1400_ts_resume NULL
434 #endif
435 
436 static struct platform_driver ucb1400_ts_driver = {
437 	.probe	= ucb1400_ts_probe,
438 	.remove	= ucb1400_ts_remove,
439 	.resume	= ucb1400_ts_resume,
440 	.driver	= {
441 		.name	= "ucb1400_ts",
442 	},
443 };
444 
ucb1400_ts_init(void)445 static int __init ucb1400_ts_init(void)
446 {
447 	return platform_driver_register(&ucb1400_ts_driver);
448 }
449 
ucb1400_ts_exit(void)450 static void __exit ucb1400_ts_exit(void)
451 {
452 	platform_driver_unregister(&ucb1400_ts_driver);
453 }
454 
455 module_param(adcsync, bool, 0444);
456 MODULE_PARM_DESC(adcsync, "Synchronize touch readings with ADCSYNC pin.");
457 
458 module_param(ts_delay, int, 0444);
459 MODULE_PARM_DESC(ts_delay, "Delay between panel setup and"
460 			    " position read. Default = 55us.");
461 
462 module_param(ts_delay_pressure, int, 0444);
463 MODULE_PARM_DESC(ts_delay_pressure,
464 		"delay between panel setup and pressure read."
465 		"  Default = 0us.");
466 
467 module_init(ucb1400_ts_init);
468 module_exit(ucb1400_ts_exit);
469 
470 MODULE_DESCRIPTION("Philips UCB1400 touchscreen driver");
471 MODULE_LICENSE("GPL");
472