1 /*
2  * wm97xx-core.c  --  Touch screen driver core for Wolfson WM9705, WM9712
3  *                    and WM9713 AC97 Codecs.
4  *
5  * Copyright 2003, 2004, 2005, 2006, 2007, 2008 Wolfson Microelectronics PLC.
6  * Author: Liam Girdwood <lrg@slimlogic.co.uk>
7  * Parts Copyright : Ian Molton <spyro@f2s.com>
8  *                   Andrew Zabolotny <zap@homelink.ru>
9  *                   Russell King <rmk@arm.linux.org.uk>
10  *
11  *  This program is free software; you can redistribute  it and/or modify it
12  *  under  the terms of  the GNU General  Public License as published by the
13  *  Free Software Foundation;  either version 2 of the  License, or (at your
14  *  option) any later version.
15  *
16  * Notes:
17  *
18  *  Features:
19  *       - supports WM9705, WM9712, WM9713
20  *       - polling mode
21  *       - continuous mode (arch-dependent)
22  *       - adjustable rpu/dpp settings
23  *       - adjustable pressure current
24  *       - adjustable sample settle delay
25  *       - 4 and 5 wire touchscreens (5 wire is WM9712 only)
26  *       - pen down detection
27  *       - battery monitor
28  *       - sample AUX adcs
29  *       - power management
30  *       - codec GPIO
31  *       - codec event notification
32  * Todo
33  *       - Support for async sampling control for noisy LCDs.
34  *
35  */
36 
37 #include <linux/module.h>
38 #include <linux/moduleparam.h>
39 #include <linux/kernel.h>
40 #include <linux/init.h>
41 #include <linux/delay.h>
42 #include <linux/string.h>
43 #include <linux/proc_fs.h>
44 #include <linux/pm.h>
45 #include <linux/interrupt.h>
46 #include <linux/bitops.h>
47 #include <linux/workqueue.h>
48 #include <linux/wm97xx.h>
49 #include <linux/uaccess.h>
50 #include <linux/io.h>
51 
52 #define TS_NAME			"wm97xx"
53 #define WM_CORE_VERSION		"1.00"
54 #define DEFAULT_PRESSURE	0xb0c0
55 
56 
57 /*
58  * Touchscreen absolute values
59  *
60  * These parameters are used to help the input layer discard out of
61  * range readings and reduce jitter etc.
62  *
63  *   o min, max:- indicate the min and max values your touch screen returns
64  *   o fuzz:- use a higher number to reduce jitter
65  *
66  * The default values correspond to Mainstone II in QVGA mode
67  *
68  * Please read
69  * Documentation/input/input-programming.txt for more details.
70  */
71 
72 static int abs_x[3] = {350, 3900, 5};
73 module_param_array(abs_x, int, NULL, 0);
74 MODULE_PARM_DESC(abs_x, "Touchscreen absolute X min, max, fuzz");
75 
76 static int abs_y[3] = {320, 3750, 40};
77 module_param_array(abs_y, int, NULL, 0);
78 MODULE_PARM_DESC(abs_y, "Touchscreen absolute Y min, max, fuzz");
79 
80 static int abs_p[3] = {0, 150, 4};
81 module_param_array(abs_p, int, NULL, 0);
82 MODULE_PARM_DESC(abs_p, "Touchscreen absolute Pressure min, max, fuzz");
83 
84 /*
85  * wm97xx IO access, all IO locking done by AC97 layer
86  */
87 int wm97xx_reg_read(struct wm97xx *wm, u16 reg)
88 {
89 	if (wm->ac97)
90 		return wm->ac97->bus->ops->read(wm->ac97, reg);
91 	else
92 		return -1;
93 }
94 EXPORT_SYMBOL_GPL(wm97xx_reg_read);
95 
96 void wm97xx_reg_write(struct wm97xx *wm, u16 reg, u16 val)
97 {
98 	/* cache digitiser registers */
99 	if (reg >= AC97_WM9713_DIG1 && reg <= AC97_WM9713_DIG3)
100 		wm->dig[(reg - AC97_WM9713_DIG1) >> 1] = val;
101 
102 	/* cache gpio regs */
103 	if (reg >= AC97_GPIO_CFG && reg <= AC97_MISC_AFE)
104 		wm->gpio[(reg - AC97_GPIO_CFG) >> 1] = val;
105 
106 	/* wm9713 irq reg */
107 	if (reg == 0x5a)
108 		wm->misc = val;
109 
110 	if (wm->ac97)
111 		wm->ac97->bus->ops->write(wm->ac97, reg, val);
112 }
113 EXPORT_SYMBOL_GPL(wm97xx_reg_write);
114 
115 /**
116  * wm97xx_read_aux_adc - Read the aux adc.
117  * @wm: wm97xx device.
118  * @adcsel: codec ADC to be read
119  *
120  * Reads the selected AUX ADC.
121  */
122 
123 int wm97xx_read_aux_adc(struct wm97xx *wm, u16 adcsel)
124 {
125 	int power_adc = 0, auxval;
126 	u16 power = 0;
127 
128 	/* get codec */
129 	mutex_lock(&wm->codec_mutex);
130 
131 	/* When the touchscreen is not in use, we may have to power up
132 	 * the AUX ADC before we can use sample the AUX inputs->
133 	 */
134 	if (wm->id == WM9713_ID2 &&
135 	    (power = wm97xx_reg_read(wm, AC97_EXTENDED_MID)) & 0x8000) {
136 		power_adc = 1;
137 		wm97xx_reg_write(wm, AC97_EXTENDED_MID, power & 0x7fff);
138 	}
139 
140 	/* Prepare the codec for AUX reading */
141 	wm->codec->aux_prepare(wm);
142 
143 	/* Turn polling mode on to read AUX ADC */
144 	wm->pen_probably_down = 1;
145 	wm->codec->poll_sample(wm, adcsel, &auxval);
146 
147 	if (power_adc)
148 		wm97xx_reg_write(wm, AC97_EXTENDED_MID, power | 0x8000);
149 
150 	wm->codec->dig_restore(wm);
151 
152 	wm->pen_probably_down = 0;
153 
154 	mutex_unlock(&wm->codec_mutex);
155 	return auxval & 0xfff;
156 }
157 EXPORT_SYMBOL_GPL(wm97xx_read_aux_adc);
158 
159 /**
160  * wm97xx_get_gpio - Get the status of a codec GPIO.
161  * @wm: wm97xx device.
162  * @gpio: gpio
163  *
164  * Get the status of a codec GPIO pin
165  */
166 
167 enum wm97xx_gpio_status wm97xx_get_gpio(struct wm97xx *wm, u32 gpio)
168 {
169 	u16 status;
170 	enum wm97xx_gpio_status ret;
171 
172 	mutex_lock(&wm->codec_mutex);
173 	status = wm97xx_reg_read(wm, AC97_GPIO_STATUS);
174 
175 	if (status & gpio)
176 		ret = WM97XX_GPIO_HIGH;
177 	else
178 		ret = WM97XX_GPIO_LOW;
179 
180 	mutex_unlock(&wm->codec_mutex);
181 	return ret;
182 }
183 EXPORT_SYMBOL_GPL(wm97xx_get_gpio);
184 
185 /**
186  * wm97xx_set_gpio - Set the status of a codec GPIO.
187  * @wm: wm97xx device.
188  * @gpio: gpio
189  *
190  *
191  * Set the status of a codec GPIO pin
192  */
193 
194 void wm97xx_set_gpio(struct wm97xx *wm, u32 gpio,
195 				enum wm97xx_gpio_status status)
196 {
197 	u16 reg;
198 
199 	mutex_lock(&wm->codec_mutex);
200 	reg = wm97xx_reg_read(wm, AC97_GPIO_STATUS);
201 
202 	if (status & WM97XX_GPIO_HIGH)
203 		reg |= gpio;
204 	else
205 		reg &= ~gpio;
206 
207 	if (wm->id == WM9712_ID2)
208 		wm97xx_reg_write(wm, AC97_GPIO_STATUS, reg << 1);
209 	else
210 		wm97xx_reg_write(wm, AC97_GPIO_STATUS, reg);
211 	mutex_unlock(&wm->codec_mutex);
212 }
213 EXPORT_SYMBOL_GPL(wm97xx_set_gpio);
214 
215 /*
216  * Codec GPIO pin configuration, this sets pin direction, polarity,
217  * stickyness and wake up.
218  */
219 void wm97xx_config_gpio(struct wm97xx *wm, u32 gpio, enum wm97xx_gpio_dir dir,
220 		   enum wm97xx_gpio_pol pol, enum wm97xx_gpio_sticky sticky,
221 		   enum wm97xx_gpio_wake wake)
222 {
223 	u16 reg;
224 
225 	mutex_lock(&wm->codec_mutex);
226 	reg = wm97xx_reg_read(wm, AC97_GPIO_POLARITY);
227 
228 	if (pol == WM97XX_GPIO_POL_HIGH)
229 		reg |= gpio;
230 	else
231 		reg &= ~gpio;
232 
233 	wm97xx_reg_write(wm, AC97_GPIO_POLARITY, reg);
234 	reg = wm97xx_reg_read(wm, AC97_GPIO_STICKY);
235 
236 	if (sticky == WM97XX_GPIO_STICKY)
237 		reg |= gpio;
238 	else
239 		reg &= ~gpio;
240 
241 	wm97xx_reg_write(wm, AC97_GPIO_STICKY, reg);
242 	reg = wm97xx_reg_read(wm, AC97_GPIO_WAKEUP);
243 
244 	if (wake == WM97XX_GPIO_WAKE)
245 		reg |= gpio;
246 	else
247 		reg &= ~gpio;
248 
249 	wm97xx_reg_write(wm, AC97_GPIO_WAKEUP, reg);
250 	reg = wm97xx_reg_read(wm, AC97_GPIO_CFG);
251 
252 	if (dir == WM97XX_GPIO_IN)
253 		reg |= gpio;
254 	else
255 		reg &= ~gpio;
256 
257 	wm97xx_reg_write(wm, AC97_GPIO_CFG, reg);
258 	mutex_unlock(&wm->codec_mutex);
259 }
260 EXPORT_SYMBOL_GPL(wm97xx_config_gpio);
261 
262 /*
263  * Configure the WM97XX_PRP value to use while system is suspended.
264  * If a value other than 0 is set then WM97xx pen detection will be
265  * left enabled in the configured mode while the system is in suspend,
266  * the device has users and suspend has not been disabled via the
267  * wakeup sysfs entries.
268  *
269  * @wm:   WM97xx device to configure
270  * @mode: WM97XX_PRP value to configure while suspended
271  */
272 void wm97xx_set_suspend_mode(struct wm97xx *wm, u16 mode)
273 {
274 	wm->suspend_mode = mode;
275 	device_init_wakeup(&wm->input_dev->dev, mode != 0);
276 }
277 EXPORT_SYMBOL_GPL(wm97xx_set_suspend_mode);
278 
279 /*
280  * Handle a pen down interrupt.
281  */
282 static void wm97xx_pen_irq_worker(struct work_struct *work)
283 {
284 	struct wm97xx *wm = container_of(work, struct wm97xx, pen_event_work);
285 	int pen_was_down = wm->pen_is_down;
286 
287 	/* do we need to enable the touch panel reader */
288 	if (wm->id == WM9705_ID2) {
289 		if (wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD) &
290 					WM97XX_PEN_DOWN)
291 			wm->pen_is_down = 1;
292 		else
293 			wm->pen_is_down = 0;
294 	} else {
295 		u16 status, pol;
296 		mutex_lock(&wm->codec_mutex);
297 		status = wm97xx_reg_read(wm, AC97_GPIO_STATUS);
298 		pol = wm97xx_reg_read(wm, AC97_GPIO_POLARITY);
299 
300 		if (WM97XX_GPIO_13 & pol & status) {
301 			wm->pen_is_down = 1;
302 			wm97xx_reg_write(wm, AC97_GPIO_POLARITY, pol &
303 						~WM97XX_GPIO_13);
304 		} else {
305 			wm->pen_is_down = 0;
306 			wm97xx_reg_write(wm, AC97_GPIO_POLARITY, pol |
307 					 WM97XX_GPIO_13);
308 		}
309 
310 		if (wm->id == WM9712_ID2)
311 			wm97xx_reg_write(wm, AC97_GPIO_STATUS, (status &
312 						~WM97XX_GPIO_13) << 1);
313 		else
314 			wm97xx_reg_write(wm, AC97_GPIO_STATUS, status &
315 						~WM97XX_GPIO_13);
316 		mutex_unlock(&wm->codec_mutex);
317 	}
318 
319 	/* If the system is not using continuous mode or it provides a
320 	 * pen down operation then we need to schedule polls while the
321 	 * pen is down.  Otherwise the machine driver is responsible
322 	 * for scheduling reads.
323 	 */
324 	if (!wm->mach_ops->acc_enabled || wm->mach_ops->acc_pen_down) {
325 		if (wm->pen_is_down && !pen_was_down) {
326 			/* Data is not availiable immediately on pen down */
327 			queue_delayed_work(wm->ts_workq, &wm->ts_reader, 1);
328 		}
329 
330 		/* Let ts_reader report the pen up for debounce. */
331 		if (!wm->pen_is_down && pen_was_down)
332 			wm->pen_is_down = 1;
333 	}
334 
335 	if (!wm->pen_is_down && wm->mach_ops->acc_enabled)
336 		wm->mach_ops->acc_pen_up(wm);
337 
338 	wm->mach_ops->irq_enable(wm, 1);
339 }
340 
341 /*
342  * Codec PENDOWN irq handler
343  *
344  * We have to disable the codec interrupt in the handler because it
345  * can take upto 1ms to clear the interrupt source. We schedule a task
346  * in a work queue to do the actual interaction with the chip.  The
347  * interrupt is then enabled again in the slow handler when the source
348  * has been cleared.
349  */
350 static irqreturn_t wm97xx_pen_interrupt(int irq, void *dev_id)
351 {
352 	struct wm97xx *wm = dev_id;
353 
354 	if (!work_pending(&wm->pen_event_work)) {
355 		wm->mach_ops->irq_enable(wm, 0);
356 		queue_work(wm->ts_workq, &wm->pen_event_work);
357 	}
358 
359 	return IRQ_HANDLED;
360 }
361 
362 /*
363  * initialise pen IRQ handler and workqueue
364  */
365 static int wm97xx_init_pen_irq(struct wm97xx *wm)
366 {
367 	u16 reg;
368 
369 	/* If an interrupt is supplied an IRQ enable operation must also be
370 	 * provided. */
371 	BUG_ON(!wm->mach_ops->irq_enable);
372 
373 	if (request_irq(wm->pen_irq, wm97xx_pen_interrupt,
374 			IRQF_SHARED | IRQF_SAMPLE_RANDOM,
375 			"wm97xx-pen", wm)) {
376 		dev_err(wm->dev,
377 			"Failed to register pen down interrupt, polling");
378 		wm->pen_irq = 0;
379 		return -EINVAL;
380 	}
381 
382 	/* Configure GPIO as interrupt source on WM971x */
383 	if (wm->id != WM9705_ID2) {
384 		BUG_ON(!wm->mach_ops->irq_gpio);
385 		reg = wm97xx_reg_read(wm, AC97_MISC_AFE);
386 		wm97xx_reg_write(wm, AC97_MISC_AFE,
387 				reg & ~(wm->mach_ops->irq_gpio));
388 		reg = wm97xx_reg_read(wm, 0x5a);
389 		wm97xx_reg_write(wm, 0x5a, reg & ~0x0001);
390 	}
391 
392 	return 0;
393 }
394 
395 static int wm97xx_read_samples(struct wm97xx *wm)
396 {
397 	struct wm97xx_data data;
398 	int rc;
399 
400 	mutex_lock(&wm->codec_mutex);
401 
402 	if (wm->mach_ops && wm->mach_ops->acc_enabled)
403 		rc = wm->mach_ops->acc_pen_down(wm);
404 	else
405 		rc = wm->codec->poll_touch(wm, &data);
406 
407 	if (rc & RC_PENUP) {
408 		if (wm->pen_is_down) {
409 			wm->pen_is_down = 0;
410 			dev_dbg(wm->dev, "pen up\n");
411 			input_report_abs(wm->input_dev, ABS_PRESSURE, 0);
412 			input_report_key(wm->input_dev, BTN_TOUCH, 0);
413 			input_sync(wm->input_dev);
414 		} else if (!(rc & RC_AGAIN)) {
415 			/* We need high frequency updates only while
416 			* pen is down, the user never will be able to
417 			* touch screen faster than a few times per
418 			* second... On the other hand, when the user
419 			* is actively working with the touchscreen we
420 			* don't want to lose the quick response. So we
421 			* will slowly increase sleep time after the
422 			* pen is up and quicky restore it to ~one task
423 			* switch when pen is down again.
424 			*/
425 			if (wm->ts_reader_interval < HZ / 10)
426 				wm->ts_reader_interval++;
427 		}
428 
429 	} else if (rc & RC_VALID) {
430 		dev_dbg(wm->dev,
431 			"pen down: x=%x:%d, y=%x:%d, pressure=%x:%d\n",
432 			data.x >> 12, data.x & 0xfff, data.y >> 12,
433 			data.y & 0xfff, data.p >> 12, data.p & 0xfff);
434 		input_report_abs(wm->input_dev, ABS_X, data.x & 0xfff);
435 		input_report_abs(wm->input_dev, ABS_Y, data.y & 0xfff);
436 		input_report_abs(wm->input_dev, ABS_PRESSURE, data.p & 0xfff);
437 		input_report_key(wm->input_dev, BTN_TOUCH, 1);
438 		input_sync(wm->input_dev);
439 		wm->pen_is_down = 1;
440 		wm->ts_reader_interval = wm->ts_reader_min_interval;
441 	} else if (rc & RC_PENDOWN) {
442 		dev_dbg(wm->dev, "pen down\n");
443 		wm->pen_is_down = 1;
444 		wm->ts_reader_interval = wm->ts_reader_min_interval;
445 	}
446 
447 	mutex_unlock(&wm->codec_mutex);
448 	return rc;
449 }
450 
451 /*
452 * The touchscreen sample reader.
453 */
454 static void wm97xx_ts_reader(struct work_struct *work)
455 {
456 	int rc;
457 	struct wm97xx *wm = container_of(work, struct wm97xx, ts_reader.work);
458 
459 	BUG_ON(!wm->codec);
460 
461 	do {
462 		rc = wm97xx_read_samples(wm);
463 	} while (rc & RC_AGAIN);
464 
465 	if (wm->pen_is_down || !wm->pen_irq)
466 		queue_delayed_work(wm->ts_workq, &wm->ts_reader,
467 				   wm->ts_reader_interval);
468 }
469 
470 /**
471  * wm97xx_ts_input_open - Open the touch screen input device.
472  * @idev:	Input device to be opened.
473  *
474  * Called by the input sub system to open a wm97xx touchscreen device.
475  * Starts the touchscreen thread and touch digitiser.
476  */
477 static int wm97xx_ts_input_open(struct input_dev *idev)
478 {
479 	struct wm97xx *wm = input_get_drvdata(idev);
480 
481 	wm->ts_workq = create_singlethread_workqueue("kwm97xx");
482 	if (wm->ts_workq == NULL) {
483 		dev_err(wm->dev,
484 			"Failed to create workqueue\n");
485 		return -EINVAL;
486 	}
487 
488 	/* start digitiser */
489 	if (wm->mach_ops && wm->mach_ops->acc_enabled)
490 		wm->codec->acc_enable(wm, 1);
491 	wm->codec->dig_enable(wm, 1);
492 
493 	INIT_DELAYED_WORK(&wm->ts_reader, wm97xx_ts_reader);
494 	INIT_WORK(&wm->pen_event_work, wm97xx_pen_irq_worker);
495 
496 	wm->ts_reader_min_interval = HZ >= 100 ? HZ / 100 : 1;
497 	if (wm->ts_reader_min_interval < 1)
498 		wm->ts_reader_min_interval = 1;
499 	wm->ts_reader_interval = wm->ts_reader_min_interval;
500 
501 	wm->pen_is_down = 0;
502 	if (wm->pen_irq)
503 		wm97xx_init_pen_irq(wm);
504 	else
505 		dev_err(wm->dev, "No IRQ specified\n");
506 
507 	/* If we either don't have an interrupt for pen down events or
508 	 * failed to acquire it then we need to poll.
509 	 */
510 	if (wm->pen_irq == 0)
511 		queue_delayed_work(wm->ts_workq, &wm->ts_reader,
512 				   wm->ts_reader_interval);
513 
514 	return 0;
515 }
516 
517 /**
518  * wm97xx_ts_input_close - Close the touch screen input device.
519  * @idev:	Input device to be closed.
520  *
521  * Called by the input sub system to close a wm97xx touchscreen
522  * device.  Kills the touchscreen thread and stops the touch
523  * digitiser.
524  */
525 
526 static void wm97xx_ts_input_close(struct input_dev *idev)
527 {
528 	struct wm97xx *wm = input_get_drvdata(idev);
529 	u16 reg;
530 
531 	if (wm->pen_irq) {
532 		/* Return the interrupt to GPIO usage (disabling it) */
533 		if (wm->id != WM9705_ID2) {
534 			BUG_ON(!wm->mach_ops->irq_gpio);
535 			reg = wm97xx_reg_read(wm, AC97_MISC_AFE);
536 			wm97xx_reg_write(wm, AC97_MISC_AFE,
537 					 reg | wm->mach_ops->irq_gpio);
538 		}
539 
540 		free_irq(wm->pen_irq, wm);
541 	}
542 
543 	wm->pen_is_down = 0;
544 
545 	/* Balance out interrupt disables/enables */
546 	if (cancel_work_sync(&wm->pen_event_work))
547 		wm->mach_ops->irq_enable(wm, 1);
548 
549 	/* ts_reader rearms itself so we need to explicitly stop it
550 	 * before we destroy the workqueue.
551 	 */
552 	cancel_delayed_work_sync(&wm->ts_reader);
553 
554 	destroy_workqueue(wm->ts_workq);
555 
556 	/* stop digitiser */
557 	wm->codec->dig_enable(wm, 0);
558 	if (wm->mach_ops && wm->mach_ops->acc_enabled)
559 		wm->codec->acc_enable(wm, 0);
560 }
561 
562 static int wm97xx_probe(struct device *dev)
563 {
564 	struct wm97xx *wm;
565 	int ret = 0, id = 0;
566 
567 	wm = kzalloc(sizeof(struct wm97xx), GFP_KERNEL);
568 	if (!wm)
569 		return -ENOMEM;
570 	mutex_init(&wm->codec_mutex);
571 
572 	wm->dev = dev;
573 	dev->driver_data = wm;
574 	wm->ac97 = to_ac97_t(dev);
575 
576 	/* check that we have a supported codec */
577 	id = wm97xx_reg_read(wm, AC97_VENDOR_ID1);
578 	if (id != WM97XX_ID1) {
579 		dev_err(dev, "Device with vendor %04x is not a wm97xx\n", id);
580 		ret = -ENODEV;
581 		goto alloc_err;
582 	}
583 
584 	wm->id = wm97xx_reg_read(wm, AC97_VENDOR_ID2);
585 
586 	dev_info(wm->dev, "detected a wm97%02x codec\n", wm->id & 0xff);
587 
588 	switch (wm->id & 0xff) {
589 #ifdef CONFIG_TOUCHSCREEN_WM9705
590 	case 0x05:
591 		wm->codec = &wm9705_codec;
592 		break;
593 #endif
594 #ifdef CONFIG_TOUCHSCREEN_WM9712
595 	case 0x12:
596 		wm->codec = &wm9712_codec;
597 		break;
598 #endif
599 #ifdef CONFIG_TOUCHSCREEN_WM9713
600 	case 0x13:
601 		wm->codec = &wm9713_codec;
602 		break;
603 #endif
604 	default:
605 		dev_err(wm->dev, "Support for wm97%02x not compiled in.\n",
606 			wm->id & 0xff);
607 		ret = -ENODEV;
608 		goto alloc_err;
609 	}
610 
611 	/* set up physical characteristics */
612 	wm->codec->phy_init(wm);
613 
614 	/* load gpio cache */
615 	wm->gpio[0] = wm97xx_reg_read(wm, AC97_GPIO_CFG);
616 	wm->gpio[1] = wm97xx_reg_read(wm, AC97_GPIO_POLARITY);
617 	wm->gpio[2] = wm97xx_reg_read(wm, AC97_GPIO_STICKY);
618 	wm->gpio[3] = wm97xx_reg_read(wm, AC97_GPIO_WAKEUP);
619 	wm->gpio[4] = wm97xx_reg_read(wm, AC97_GPIO_STATUS);
620 	wm->gpio[5] = wm97xx_reg_read(wm, AC97_MISC_AFE);
621 
622 	wm->input_dev = input_allocate_device();
623 	if (wm->input_dev == NULL) {
624 		ret = -ENOMEM;
625 		goto alloc_err;
626 	}
627 
628 	/* set up touch configuration */
629 	wm->input_dev->name = "wm97xx touchscreen";
630 	wm->input_dev->phys = "wm97xx";
631 	wm->input_dev->open = wm97xx_ts_input_open;
632 	wm->input_dev->close = wm97xx_ts_input_close;
633 
634 	__set_bit(EV_ABS, wm->input_dev->evbit);
635 	__set_bit(EV_KEY, wm->input_dev->evbit);
636 	__set_bit(BTN_TOUCH, wm->input_dev->keybit);
637 
638 	input_set_abs_params(wm->input_dev, ABS_X, abs_x[0], abs_x[1],
639 			     abs_x[2], 0);
640 	input_set_abs_params(wm->input_dev, ABS_Y, abs_y[0], abs_y[1],
641 			     abs_y[2], 0);
642 	input_set_abs_params(wm->input_dev, ABS_PRESSURE, abs_p[0], abs_p[1],
643 			     abs_p[2], 0);
644 
645 	input_set_drvdata(wm->input_dev, wm);
646 	wm->input_dev->dev.parent = dev;
647 
648 	ret = input_register_device(wm->input_dev);
649 	if (ret < 0)
650 		goto dev_alloc_err;
651 
652 	/* register our battery device */
653 	wm->battery_dev = platform_device_alloc("wm97xx-battery", -1);
654 	if (!wm->battery_dev) {
655 		ret = -ENOMEM;
656 		goto batt_err;
657 	}
658 	platform_set_drvdata(wm->battery_dev, wm);
659 	wm->battery_dev->dev.parent = dev;
660 	ret = platform_device_add(wm->battery_dev);
661 	if (ret < 0)
662 		goto batt_reg_err;
663 
664 	/* register our extended touch device (for machine specific
665 	 * extensions) */
666 	wm->touch_dev = platform_device_alloc("wm97xx-touch", -1);
667 	if (!wm->touch_dev) {
668 		ret = -ENOMEM;
669 		goto touch_err;
670 	}
671 	platform_set_drvdata(wm->touch_dev, wm);
672 	wm->touch_dev->dev.parent = dev;
673 	ret = platform_device_add(wm->touch_dev);
674 	if (ret < 0)
675 		goto touch_reg_err;
676 
677 	return ret;
678 
679  touch_reg_err:
680 	platform_device_put(wm->touch_dev);
681  touch_err:
682 	platform_device_unregister(wm->battery_dev);
683 	wm->battery_dev = NULL;
684  batt_reg_err:
685 	platform_device_put(wm->battery_dev);
686  batt_err:
687 	input_unregister_device(wm->input_dev);
688 	wm->input_dev = NULL;
689  dev_alloc_err:
690 	input_free_device(wm->input_dev);
691  alloc_err:
692 	kfree(wm);
693 
694 	return ret;
695 }
696 
697 static int wm97xx_remove(struct device *dev)
698 {
699 	struct wm97xx *wm = dev_get_drvdata(dev);
700 
701 	platform_device_unregister(wm->battery_dev);
702 	platform_device_unregister(wm->touch_dev);
703 	input_unregister_device(wm->input_dev);
704 	kfree(wm);
705 
706 	return 0;
707 }
708 
709 #ifdef CONFIG_PM
710 static int wm97xx_suspend(struct device *dev, pm_message_t state)
711 {
712 	struct wm97xx *wm = dev_get_drvdata(dev);
713 	u16 reg;
714 	int suspend_mode;
715 
716 	if (device_may_wakeup(&wm->input_dev->dev))
717 		suspend_mode = wm->suspend_mode;
718 	else
719 		suspend_mode = 0;
720 
721 	if (wm->input_dev->users)
722 		cancel_delayed_work_sync(&wm->ts_reader);
723 
724 	/* Power down the digitiser (bypassing the cache for resume) */
725 	reg = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER2);
726 	reg &= ~WM97XX_PRP_DET_DIG;
727 	if (wm->input_dev->users)
728 		reg |= suspend_mode;
729 	wm->ac97->bus->ops->write(wm->ac97, AC97_WM97XX_DIGITISER2, reg);
730 
731 	/* WM9713 has an additional power bit - turn it off if there
732 	 * are no users or if suspend mode is zero. */
733 	if (wm->id == WM9713_ID2 &&
734 	    (!wm->input_dev->users || !suspend_mode)) {
735 		reg = wm97xx_reg_read(wm, AC97_EXTENDED_MID) | 0x8000;
736 		wm97xx_reg_write(wm, AC97_EXTENDED_MID, reg);
737 	}
738 
739 	return 0;
740 }
741 
742 static int wm97xx_resume(struct device *dev)
743 {
744 	struct wm97xx *wm = dev_get_drvdata(dev);
745 
746 	/* restore digitiser and gpios */
747 	if (wm->id == WM9713_ID2) {
748 		wm97xx_reg_write(wm, AC97_WM9713_DIG1, wm->dig[0]);
749 		wm97xx_reg_write(wm, 0x5a, wm->misc);
750 		if (wm->input_dev->users) {
751 			u16 reg;
752 			reg = wm97xx_reg_read(wm, AC97_EXTENDED_MID) & 0x7fff;
753 			wm97xx_reg_write(wm, AC97_EXTENDED_MID, reg);
754 		}
755 	}
756 
757 	wm97xx_reg_write(wm, AC97_WM9713_DIG2, wm->dig[1]);
758 	wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2]);
759 
760 	wm97xx_reg_write(wm, AC97_GPIO_CFG, wm->gpio[0]);
761 	wm97xx_reg_write(wm, AC97_GPIO_POLARITY, wm->gpio[1]);
762 	wm97xx_reg_write(wm, AC97_GPIO_STICKY, wm->gpio[2]);
763 	wm97xx_reg_write(wm, AC97_GPIO_WAKEUP, wm->gpio[3]);
764 	wm97xx_reg_write(wm, AC97_GPIO_STATUS, wm->gpio[4]);
765 	wm97xx_reg_write(wm, AC97_MISC_AFE, wm->gpio[5]);
766 
767 	if (wm->input_dev->users && !wm->pen_irq) {
768 		wm->ts_reader_interval = wm->ts_reader_min_interval;
769 		queue_delayed_work(wm->ts_workq, &wm->ts_reader,
770 				   wm->ts_reader_interval);
771 	}
772 
773 	return 0;
774 }
775 
776 #else
777 #define wm97xx_suspend		NULL
778 #define wm97xx_resume		NULL
779 #endif
780 
781 /*
782  * Machine specific operations
783  */
784 int wm97xx_register_mach_ops(struct wm97xx *wm,
785 			     struct wm97xx_mach_ops *mach_ops)
786 {
787 	mutex_lock(&wm->codec_mutex);
788 	if (wm->mach_ops) {
789 		mutex_unlock(&wm->codec_mutex);
790 		return -EINVAL;
791 	}
792 	wm->mach_ops = mach_ops;
793 	mutex_unlock(&wm->codec_mutex);
794 
795 	return 0;
796 }
797 EXPORT_SYMBOL_GPL(wm97xx_register_mach_ops);
798 
799 void wm97xx_unregister_mach_ops(struct wm97xx *wm)
800 {
801 	mutex_lock(&wm->codec_mutex);
802 	wm->mach_ops = NULL;
803 	mutex_unlock(&wm->codec_mutex);
804 }
805 EXPORT_SYMBOL_GPL(wm97xx_unregister_mach_ops);
806 
807 static struct device_driver wm97xx_driver = {
808 	.name =		"wm97xx-ts",
809 	.bus =		&ac97_bus_type,
810 	.owner =	THIS_MODULE,
811 	.probe =	wm97xx_probe,
812 	.remove =	wm97xx_remove,
813 	.suspend =	wm97xx_suspend,
814 	.resume =	wm97xx_resume,
815 };
816 
817 static int __init wm97xx_init(void)
818 {
819 	return driver_register(&wm97xx_driver);
820 }
821 
822 static void __exit wm97xx_exit(void)
823 {
824 	driver_unregister(&wm97xx_driver);
825 }
826 
827 module_init(wm97xx_init);
828 module_exit(wm97xx_exit);
829 
830 /* Module information */
831 MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
832 MODULE_DESCRIPTION("WM97xx Core - Touch Screen / AUX ADC / GPIO Driver");
833 MODULE_LICENSE("GPL");
834