summaryrefslogtreecommitdiffstats
path: root/drivers/input/touchscreen/wm97xx-core.c
blob: 6b75c9f660ae213294ac656e91e4b961fbb8f083 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
/*
 * wm97xx-core.c  --  Touch screen driver core for Wolfson WM9705, WM9712
 *                    and WM9713 AC97 Codecs.
 *
 * Copyright 2003, 2004, 2005, 2006, 2007, 2008 Wolfson Microelectronics PLC.
 * Author: Liam Girdwood <lrg@slimlogic.co.uk>
 * Parts Copyright : Ian Molton <spyro@f2s.com>
 *                   Andrew Zabolotny <zap@homelink.ru>
 *                   Russell King <rmk@arm.linux.org.uk>
 *
 *  This program is free software; you can redistribute  it and/or modify it
 *  under  the terms of  the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 * Notes:
 *
 *  Features:
 *       - supports WM9705, WM9712, WM9713
 *       - polling mode
 *       - continuous mode (arch-dependent)
 *       - adjustable rpu/dpp settings
 *       - adjustable pressure current
 *       - adjustable sample settle delay
 *       - 4 and 5 wire touchscreens (5 wire is WM9712 only)
 *       - pen down detection
 *       - battery monitor
 *       - sample AUX adcs
 *       - power management
 *       - codec GPIO
 *       - codec event notification
 * Todo
 *       - Support for async sampling control for noisy LCDs.
 *
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/string.h>
#include <linux/proc_fs.h>
#include <linux/pm.h>
#include <linux/interrupt.h>
#include <linux/bitops.h>
#include <linux/workqueue.h>
#include <linux/wm97xx.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/slab.h>

#define TS_NAME			"wm97xx"
#define WM_CORE_VERSION		"1.00"
#define DEFAULT_PRESSURE	0xb0c0


/*
 * Touchscreen absolute values
 *
 * These parameters are used to help the input layer discard out of
 * range readings and reduce jitter etc.
 *
 *   o min, max:- indicate the min and max values your touch screen returns
 *   o fuzz:- use a higher number to reduce jitter
 *
 * The default values correspond to Mainstone II in QVGA mode
 *
 * Please read
 * Documentation/input/input-programming.txt for more details.
 */

static int abs_x[3] = {350, 3900, 5};
module_param_array(abs_x, int, NULL, 0);
MODULE_PARM_DESC(abs_x, "Touchscreen absolute X min, max, fuzz");

static int abs_y[3] = {320, 3750, 40};
module_param_array(abs_y, int, NULL, 0);
MODULE_PARM_DESC(abs_y, "Touchscreen absolute Y min, max, fuzz");

static int abs_p[3] = {0, 150, 4};
module_param_array(abs_p, int, NULL, 0);
MODULE_PARM_DESC(abs_p, "Touchscreen absolute Pressure min, max, fuzz");

/*
 * wm97xx IO access, all IO locking done by AC97 layer
 */
int wm97xx_reg_read(struct wm97xx *wm, u16 reg)
{
	if (wm->ac97)
		return wm->ac97->bus->ops->read(wm->ac97, reg);
	else
		return -1;
}
EXPORT_SYMBOL_GPL(wm97xx_reg_read);

void wm97xx_reg_write(struct wm97xx *wm, u16 reg, u16 val)
{
	/* cache digitiser registers */
	if (reg >= AC97_WM9713_DIG1 && reg <= AC97_WM9713_DIG3)
		wm->dig[(reg - AC97_WM9713_DIG1) >> 1] = val;

	/* cache gpio regs */
	if (reg >= AC97_GPIO_CFG && reg <= AC97_MISC_AFE)
		wm->gpio[(reg - AC97_GPIO_CFG) >> 1] = val;

	/* wm9713 irq reg */
	if (reg == 0x5a)
		wm->misc = val;

	if (wm->ac97)
		wm->ac97->bus->ops->write(wm->ac97, reg, val);
}
EXPORT_SYMBOL_GPL(wm97xx_reg_write);

/**
 * wm97xx_read_aux_adc - Read the aux adc.
 * @wm: wm97xx device.
 * @adcsel: codec ADC to be read
 *
 * Reads the selected AUX ADC.
 */

int wm97xx_read_aux_adc(struct wm97xx *wm, u16 adcsel)
{
	int power_adc = 0, auxval;
	u16 power = 0;
	int rc = 0;
	int timeout = 0;

	/* get codec */
	mutex_lock(&wm->codec_mutex);

	/* When the touchscreen is not in use, we may have to power up
	 * the AUX ADC before we can use sample the AUX inputs->
	 */
	if (wm->id == WM9713_ID2 &&
	    (power = wm97xx_reg_read(wm, AC97_EXTENDED_MID)) & 0x8000) {
		power_adc = 1;
		wm97xx_reg_write(wm, AC97_EXTENDED_MID, power & 0x7fff);
	}

	/* Prepare the codec for AUX reading */
	wm->codec->aux_prepare(wm);

	/* Turn polling mode on to read AUX ADC */
	wm->pen_probably_down = 1;

	while (rc != RC_VALID && timeout++ < 5)
		rc = wm->codec->poll_sample(wm, adcsel, &auxval);

	if (power_adc)
		wm97xx_reg_write(wm, AC97_EXTENDED_MID, power | 0x8000);

	wm->codec->dig_restore(wm);

	wm->pen_probably_down = 0;

	if (timeout >= 5) {
		dev_err(wm->dev,
			"timeout reading auxadc %d, disabling digitiser\n",
			adcsel);
		wm->codec->dig_enable(wm, false);
	}

	mutex_unlock(&wm->codec_mutex);
	return (rc == RC_VALID ? auxval & 0xfff : -EBUSY);
}
EXPORT_SYMBOL_GPL(wm97xx_read_aux_adc);

/**
 * wm97xx_get_gpio - Get the status of a codec GPIO.
 * @wm: wm97xx device.
 * @gpio: gpio
 *
 * Get the status of a codec GPIO pin
 */

enum wm97xx_gpio_status wm97xx_get_gpio(struct wm97xx *wm, u32 gpio)
{
	u16 status;
	enum wm97xx_gpio_status ret;

	mutex_lock(&wm->codec_mutex);
	status = wm97xx_reg_read(wm, AC97_GPIO_STATUS);

	if (status & gpio)
		ret = WM97XX_GPIO_HIGH;
	else
		ret = WM97XX_GPIO_LOW;

	mutex_unlock(&wm->codec_mutex);
	return ret;
}
EXPORT_SYMBOL_GPL(wm97xx_get_gpio);

/**
 * wm97xx_set_gpio - Set the status of a codec GPIO.
 * @wm: wm97xx device.
 * @gpio: gpio
 *
 *
 * Set the status of a codec GPIO pin
 */

void wm97xx_set_gpio(struct wm97xx *wm, u32 gpio,
				enum wm97xx_gpio_status status)
{
	u16 reg;

	mutex_lock(&wm->codec_mutex);
	reg = wm97xx_reg_read(wm, AC97_GPIO_STATUS);

	if (status == WM97XX_GPIO_HIGH)
		reg |= gpio;
	else
		reg &= ~gpio;

	if (wm->id == WM9712_ID2 && wm->variant != WM97xx_WM1613)
		wm97xx_reg_write(wm, AC97_GPIO_STATUS, reg << 1);
	else
		wm97xx_reg_write(wm, AC97_GPIO_STATUS, reg);
	mutex_unlock(&wm->codec_mutex);
}
EXPORT_SYMBOL_GPL(wm97xx_set_gpio);

/*
 * Codec GPIO pin configuration, this sets pin direction, polarity,
 * stickyness and wake up.
 */
void wm97xx_config_gpio(struct wm97xx *wm, u32 gpio, enum wm97xx_gpio_dir dir,
		   enum wm97xx_gpio_pol pol, enum wm97xx_gpio_sticky sticky,
		   enum wm97xx_gpio_wake wake)
{
	u16 reg;

	mutex_lock(&wm->codec_mutex);
	reg = wm97xx_reg_read(wm, AC97_GPIO_POLARITY);

	if (pol == WM97XX_GPIO_POL_HIGH)
		reg |= gpio;
	else
		reg &= ~gpio;

	wm97xx_reg_write(wm, AC97_GPIO_POLARITY, reg);
	reg = wm97xx_reg_read(wm, AC97_GPIO_STICKY);

	if (sticky == WM97XX_GPIO_STICKY)
		reg |= gpio;
	else
		reg &= ~gpio;

	wm97xx_reg_write(wm, AC97_GPIO_STICKY, reg);
	reg = wm97xx_reg_read(wm, AC97_GPIO_WAKEUP);

	if (wake == WM97XX_GPIO_WAKE)
		reg |= gpio;
	else
		reg &= ~gpio;

	wm97xx_reg_write(wm, AC97_GPIO_WAKEUP, reg);
	reg = wm97xx_reg_read(wm, AC97_GPIO_CFG);

	if (dir == WM97XX_GPIO_IN)
		reg |= gpio;
	else
		reg &= ~gpio;

	wm97xx_reg_write(wm, AC97_GPIO_CFG, reg);
	mutex_unlock(&wm->codec_mutex);
}
EXPORT_SYMBOL_GPL(wm97xx_config_gpio);

/*
 * Configure the WM97XX_PRP value to use while system is suspended.
 * If a value other than 0 is set then WM97xx pen detection will be
 * left enabled in the configured mode while the system is in suspend,
 * the device has users and suspend has not been disabled via the
 * wakeup sysfs entries.
 *
 * @wm:   WM97xx device to configure
 * @mode: WM97XX_PRP value to configure while suspended
 */
void wm97xx_set_suspend_mode(struct wm97xx *wm, u16 mode)
{
	wm->suspend_mode = mode;
	device_init_wakeup(&wm->input_dev->dev, mode != 0);
}
EXPORT_SYMBOL_GPL(wm97xx_set_suspend_mode);

/*
 * Handle a pen down interrupt.
 */
static void wm97xx_pen_irq_worker(struct work_struct *work)
{
	struct wm97xx *wm = container_of(work, struct wm97xx, pen_event_work);
	int pen_was_down = wm->pen_is_down;

	/* do we need to enable the touch panel reader */
	if (wm->id == WM9705_ID2) {
		if (wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD) &
					WM97XX_PEN_DOWN)
			wm->pen_is_down = 1;
		else
			wm->pen_is_down = 0;
	} else {
		u16 status, pol;
		mutex_lock(&wm->codec_mutex);
		status = wm97xx_reg_read(wm, AC97_GPIO_STATUS);
		pol = wm97xx_reg_read(wm, AC97_GPIO_POLARITY);

		if (WM97XX_GPIO_13 & pol & status) {
			wm->pen_is_down = 1;
			wm97xx_reg_write(wm, AC97_GPIO_POLARITY, pol &
						~WM97XX_GPIO_13);
		} else {
			wm->pen_is_down = 0;
			wm97xx_reg_write(wm, AC97_GPIO_POLARITY, pol |
					 WM97XX_GPIO_13);
		}

		if (wm->id == WM9712_ID2 && wm->variant != WM97xx_WM1613)
			wm97xx_reg_write(wm, AC97_GPIO_STATUS, (status &
						~WM97XX_GPIO_13) << 1);
		else
			wm97xx_reg_write(wm, AC97_GPIO_STATUS, status &
						~WM97XX_GPIO_13);
		mutex_unlock(&wm->codec_mutex);
	}

	/* If the system is not using continuous mode or it provides a
	 * pen down operation then we need to schedule polls while the
	 * pen is down.  Otherwise the machine driver is responsible
	 * for scheduling reads.
	 */
	if (!wm->mach_ops->acc_enabled || wm->mach_ops->acc_pen_down) {
		if (wm->pen_is_down && !pen_was_down) {
			/* Data is not availiable immediately on pen down */
			queue_delayed_work(wm->ts_workq, &wm->ts_reader, 1);
		}

		/* Let ts_reader report the pen up for debounce. */
		if (!wm->pen_is_down && pen_was_down)
			wm->pen_is_down = 1;
	}

	if (!wm->pen_is_down && wm->mach_ops->acc_enabled)
		wm->mach_ops->acc_pen_up(wm);

	wm->mach_ops->irq_enable(wm, 1);
}

/*
 * Codec PENDOWN irq handler
 *
 * We have to disable the codec interrupt in the handler because it
 * can take upto 1ms to clear the interrupt source. We schedule a task
 * in a work queue to do the actual interaction with the chip.  The
 * interrupt is then enabled again in the slow handler when the source
 * has been cleared.
 */
static irqreturn_t wm97xx_pen_interrupt(int irq, void *dev_id)
{
	struct wm97xx *wm = dev_id;

	if (!work_pending(&wm->pen_event_work)) {
		wm->mach_ops->irq_enable(wm, 0);
		queue_work(wm->ts_workq, &wm->pen_event_work);
	}

	return IRQ_HANDLED;
}

/*
 * initialise pen IRQ handler and workqueue
 */
static int wm97xx_init_pen_irq(struct wm97xx *wm)
{
	u16 reg;

	/* If an interrupt is supplied an IRQ enable operation must also be
	 * provided. */
	BUG_ON(!wm->mach_ops->irq_enable);

	if (request_irq(wm->pen_irq, wm97xx_pen_interrupt, IRQF_SHARED,
			"wm97xx-pen", wm)) {
		dev_err(wm->dev,
			"Failed to register pen down interrupt, polling");
		wm->pen_irq = 0;
		return -EINVAL;
	}

	/* Configure GPIO as interrupt source on WM971x */
	if (wm->id != WM9705_ID2) {
		BUG_ON(!wm->mach_ops->irq_gpio);
		reg = wm97xx_reg_read(wm, AC97_MISC_AFE);
		wm97xx_reg_write(wm, AC97_MISC_AFE,
				reg & ~(wm->mach_ops->irq_gpio));
		reg = wm97xx_reg_read(wm, 0x5a);
		wm97xx_reg_write(wm, 0x5a, reg & ~0x0001);
	}

	return 0;
}

static int wm97xx_read_samples(struct wm97xx *wm)
{
	struct wm97xx_data data;
	int rc;

	mutex_lock(&wm->codec_mutex);

	if (wm->mach_ops && wm->mach_ops->acc_enabled)
		rc = wm->mach_ops->acc_pen_down(wm);
	else
		rc = wm->codec->poll_touch(wm, &data);

	if (rc & RC_PENUP) {
		if (wm->pen_is_down) {
			wm->pen_is_down = 0;
			dev_dbg(wm->dev, "pen up\n");
			input_report_abs(wm->input_dev, ABS_PRESSURE, 0);
			input_report_key(wm->input_dev, BTN_TOUCH, 0);
			input_sync(wm->input_dev);
		} else if (!(rc & RC_AGAIN)) {
			/* We need high frequency updates only while
			* pen is down, the user never will be able to
			* touch screen faster than a few times per
			* second... On the other hand, when the user
			* is actively working with the touchscreen we
			* don't want to lose the quick response. So we
			* will slowly increase sleep time after the
			* pen is up and quicky restore it to ~one task
			* switch when pen is down again.
			*/
			if (wm->ts_reader_interval < HZ / 10)
				wm->ts_reader_interval++;
		}

	} else if (rc & RC_VALID) {
		dev_dbg(wm->dev,
			"pen down: x=%x:%d, y=%x:%d, pressure=%x:%d\n",
			data.x >> 12, data.x & 0xfff, data.y >> 12,
			data.y & 0xfff, data.p >> 12, data.p & 0xfff);
		input_report_abs(wm->input_dev, ABS_X, data.x & 0xfff);
		input_report_abs(wm->input_dev, ABS_Y, data.y & 0xfff);
		input_report_abs(wm->input_dev, ABS_PRESSURE, data.p & 0xfff);
		input_report_key(wm->input_dev, BTN_TOUCH, 1);
		input_sync(wm->input_dev);
		wm->pen_is_down = 1;
		wm->ts_reader_interval = wm->ts_reader_min_interval;
	} else if (rc & RC_PENDOWN) {
		dev_dbg(wm->dev, "pen down\n");
		wm->pen_is_down = 1;
		wm->ts_reader_interval = wm->ts_reader_min_interval;
	}

	mutex_unlock(&wm->codec_mutex);
	return rc;
}

/*
* The touchscreen sample reader.
*/
static void wm97xx_ts_reader(struct work_struct *work)
{
	int rc;
	struct wm97xx *wm = container_of(work, struct wm97xx, ts_reader.work);

	BUG_ON(!wm->codec);

	do {
		rc = wm97xx_read_samples(wm);
	} while (rc & RC_AGAIN);

	if (wm->pen_is_down || !wm->pen_irq)
		queue_delayed_work(wm->ts_workq, &wm->ts_reader,
				   wm->ts_reader_interval);
}

/**
 * wm97xx_ts_input_open - Open the touch screen input device.
 * @idev:	Input device to be opened.
 *
 * Called by the input sub system to open a wm97xx touchscreen device.
 * Starts the touchscreen thread and touch digitiser.
 */
static int wm97xx_ts_input_open(struct input_dev *idev)
{
	struct wm97xx *wm = input_get_drvdata(idev);

	wm->ts_workq = create_singlethread_workqueue("kwm97xx");
	if (wm->ts_workq == NULL) {
		dev_err(wm->dev,
			"Failed to create workqueue\n");
		return -EINVAL;
	}

	/* start digitiser */
	if (wm->mach_ops && wm->mach_ops->acc_enabled)
		wm->codec->acc_enable(wm, 1);
	wm->codec->dig_enable(wm, 1);

	INIT_DELAYED_WORK(&wm->ts_reader, wm97xx_ts_reader);
	INIT_WORK(&wm->pen_event_work, wm97xx_pen_irq_worker);

	wm->ts_reader_min_interval = HZ >= 100 ? HZ / 100 : 1;
	if (wm->ts_reader_min_interval < 1)
		wm->ts_reader_min_interval = 1;
	wm->ts_reader_interval = wm->ts_reader_min_interval;

	wm->pen_is_down = 0;
	if (wm->pen_irq)
		wm97xx_init_pen_irq(wm);
	else
		dev_err(wm->dev, "No IRQ specified\n");

	/* If we either don't have an interrupt for pen down events or
	 * failed to acquire it then we need to poll.
	 */
	if (wm->pen_irq == 0)
		queue_delayed_work(wm->ts_workq, &wm->ts_reader,
				   wm->ts_reader_interval);

	return 0;
}

/**
 * wm97xx_ts_input_close - Close the touch screen input device.
 * @idev:	Input device to be closed.
 *
 * Called by the input sub system to close a wm97xx touchscreen
 * device.  Kills the touchscreen thread and stops the touch
 * digitiser.
 */

static void wm97xx_ts_input_close(struct input_dev *idev)
{
	struct wm97xx *wm = input_get_drvdata(idev);
	u16 reg;

	if (wm->pen_irq) {
		/* Return the interrupt to GPIO usage (disabling it) */
		if (wm->id != WM9705_ID2) {
			BUG_ON(!wm->mach_ops->irq_gpio);
			reg = wm97xx_reg_read(wm, AC97_MISC_AFE);
			wm97xx_reg_write(wm, AC97_MISC_AFE,
					 reg | wm->mach_ops->irq_gpio);
		}

		free_irq(wm->pen_irq, wm);
	}

	wm->pen_is_down = 0;

	/* Balance out interrupt disables/enables */
	if (cancel_work_sync(&wm->pen_event_work))
		wm->mach_ops->irq_enable(wm, 1);

	/* ts_reader rearms itself so we need to explicitly stop it
	 * before we destroy the workqueue.
	 */
	cancel_delayed_work_sync(&wm->ts_reader);

	destroy_workqueue(wm->ts_workq);

	/* stop digitiser */
	wm->codec->dig_enable(wm, 0);
	if (wm->mach_ops && wm->mach_ops->acc_enabled)
		wm->codec->acc_enable(wm, 0);
}

static int wm97xx_probe(struct device *dev)
{
	struct wm97xx *wm;
	struct wm97xx_pdata *pdata = dev->platform_data;
	int ret = 0, id = 0;

	wm = kzalloc(sizeof(struct wm97xx), GFP_KERNEL);
	if (!wm)
		return -ENOMEM;
	mutex_init(&wm->codec_mutex);

	wm->dev = dev;
	dev_set_drvdata(dev, wm);
	wm->ac97 = to_ac97_t(dev);

	/* check that we have a supported codec */
	id = wm97xx_reg_read(wm, AC97_VENDOR_ID1);
	if (id != WM97XX_ID1) {
		dev_err(dev, "Device with vendor %04x is not a wm97xx\n", id);
		ret = -ENODEV;
		goto alloc_err;
	}

	wm->id = wm97xx_reg_read(wm, AC97_VENDOR_ID2);

	wm->variant = WM97xx_GENERIC;

	dev_info(wm->dev, "detected a wm97%02x codec\n", wm->id & 0xff);

	switch (wm->id & 0xff) {
#ifdef CONFIG_TOUCHSCREEN_WM9705
	case 0x05:
		wm->codec = &wm9705_codec;
		break;
#endif
#ifdef CONFIG_TOUCHSCREEN_WM9712
	case 0x12:
		wm->codec = &wm9712_codec;
		break;
#endif
#ifdef CONFIG_TOUCHSCREEN_WM9713
	case 0x13:
		wm->codec = &wm9713_codec;
		break;
#endif
	default:
		dev_err(wm->dev, "Support for wm97%02x not compiled in.\n",
			wm->id & 0xff);
		ret = -ENODEV;
		goto alloc_err;
	}

	/* set up physical characteristics */
	wm->codec->phy_init(wm);

	/* load gpio cache */
	wm->gpio[0] = wm97xx_reg_read(wm, AC97_GPIO_CFG);
	wm->gpio[1] = wm97xx_reg_read(wm, AC97_GPIO_POLARITY);
	wm->gpio[2] = wm97xx_reg_read(wm, AC97_GPIO_STICKY);
	wm->gpio[3] = wm97xx_reg_read(wm, AC97_GPIO_WAKEUP);
	wm->gpio[4] = wm97xx_reg_read(wm, AC97_GPIO_STATUS);
	wm->gpio[5] = wm97xx_reg_read(wm, AC97_MISC_AFE);

	wm->input_dev = input_allocate_device();
	if (wm->input_dev == NULL) {
		ret = -ENOMEM;
		goto alloc_err;
	}

	/* set up touch configuration */
	wm->input_dev->name = "wm97xx touchscreen";
	wm->input_dev->phys = "wm97xx";
	wm->input_dev->open = wm97xx_ts_input_open;
	wm->input_dev->close = wm97xx_ts_input_close;

	__set_bit(EV_ABS, wm->input_dev->evbit);
	__set_bit(EV_KEY, wm->input_dev->evbit);
	__set_bit(BTN_TOUCH, wm->input_dev->keybit);

	input_set_abs_params(wm->input_dev, ABS_X, abs_x[0], abs_x[1],
			     abs_x[2], 0);
	input_set_abs_params(wm->input_dev, ABS_Y, abs_y[0], abs_y[1],
			     abs_y[2], 0);
	input_set_abs_params(wm->input_dev, ABS_PRESSURE, abs_p[0], abs_p[1],
			     abs_p[2], 0);

	input_set_drvdata(wm->input_dev, wm);
	wm->input_dev->dev.parent = dev;

	ret = input_register_device(wm->input_dev);
	if (ret < 0)
		goto dev_alloc_err;

	/* register our battery device */
	wm->battery_dev = platform_device_alloc("wm97xx-battery", -1);
	if (!wm->battery_dev) {
		ret = -ENOMEM;
		goto batt_err;
	}
	platform_set_drvdata(wm->battery_dev, wm);
	wm->battery_dev->dev.parent = dev;
	wm->battery_dev->dev.platform_data = pdata;
	ret = platform_device_add(wm->battery_dev);
	if (ret < 0)
		goto batt_reg_err;

	/* register our extended touch device (for machine specific
	 * extensions) */
	wm->touch_dev = platform_device_alloc("wm97xx-touch", -1);
	if (!wm->touch_dev) {
		ret = -ENOMEM;
		goto touch_err;
	}
	platform_set_drvdata(wm->touch_dev, wm);
	wm->touch_dev->dev.parent = dev;
	wm->touch_dev->dev.platform_data = pdata;
	ret = platform_device_add(wm->touch_dev);
	if (ret < 0)
		goto touch_reg_err;

	return ret;

 touch_reg_err:
	platform_device_put(wm->touch_dev);
 touch_err:
	platform_device_del(wm->battery_dev);
 batt_reg_err:
	platform_device_put(wm->battery_dev);
 batt_err:
	input_unregister_device(wm->input_dev);
	wm->input_dev = NULL;
 dev_alloc_err:
	input_free_device(wm->input_dev);
 alloc_err:
	kfree(wm);

	return ret;
}

static int wm97xx_remove(struct device *dev)
{
	struct wm97xx *wm = dev_get_drvdata(dev);

	platform_device_unregister(wm->battery_dev);
	platform_device_unregister(wm->touch_dev);
	input_unregister_device(wm->input_dev);
	kfree(wm);

	return 0;
}

#ifdef CONFIG_PM
static int wm97xx_suspend(struct device *dev, pm_message_t state)
{
	struct wm97xx *wm = dev_get_drvdata(dev);
	u16 reg;
	int suspend_mode;

	if (device_may_wakeup(&wm->input_dev->dev))
		suspend_mode = wm->suspend_mode;
	else
		suspend_mode = 0;

	if (wm->input_dev->users)
		cancel_delayed_work_sync(&wm->ts_reader);

	/* Power down the digitiser (bypassing the cache for resume) */
	reg = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER2);
	reg &= ~WM97XX_PRP_DET_DIG;
	if (wm->input_dev->users)
		reg |= suspend_mode;
	wm->ac97->bus->ops->write(wm->ac97, AC97_WM97XX_DIGITISER2, reg);

	/* WM9713 has an additional power bit - turn it off if there
	 * are no users or if suspend mode is zero. */
	if (wm->id == WM9713_ID2 &&
	    (!wm->input_dev->users || !suspend_mode)) {
		reg = wm97xx_reg_read(wm, AC97_EXTENDED_MID) | 0x8000;
		wm97xx_reg_write(wm, AC97_EXTENDED_MID, reg);
	}

	return 0;
}

static int wm97xx_resume(struct device *dev)
{
	struct wm97xx *wm = dev_get_drvdata(dev);

	/* restore digitiser and gpios */
	if (wm->id == WM9713_ID2) {
		wm97xx_reg_write(wm, AC97_WM9713_DIG1, wm->dig[0]);
		wm97xx_reg_write(wm, 0x5a, wm->misc);
		if (wm->input_dev->users) {
			u16 reg;
			reg = wm97xx_reg_read(wm, AC97_EXTENDED_MID) & 0x7fff;
			wm97xx_reg_write(wm, AC97_EXTENDED_MID, reg);
		}
	}

	wm97xx_reg_write(wm, AC97_WM9713_DIG2, wm->dig[1]);
	wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2]);

	wm97xx_reg_write(wm, AC97_GPIO_CFG, wm->gpio[0]);
	wm97xx_reg_write(wm, AC97_GPIO_POLARITY, wm->gpio[1]);
	wm97xx_reg_write(wm, AC97_GPIO_STICKY, wm->gpio[2]);
	wm97xx_reg_write(wm, AC97_GPIO_WAKEUP, wm->gpio[3]);
	wm97xx_reg_write(wm, AC97_GPIO_STATUS, wm->gpio[4]);
	wm97xx_reg_write(wm, AC97_MISC_AFE, wm->gpio[5]);

	if (wm->input_dev->users && !wm->pen_irq) {
		wm->ts_reader_interval = wm->ts_reader_min_interval;
		queue_delayed_work(wm->ts_workq, &wm->ts_reader,
				   wm->ts_reader_interval);
	}

	return 0;
}

#else
#define wm97xx_suspend		NULL
#define wm97xx_resume		NULL
#endif

/*
 * Machine specific operations
 */
int wm97xx_register_mach_ops(struct wm97xx *wm,
			     struct wm97xx_mach_ops *mach_ops)
{
	mutex_lock(&wm->codec_mutex);
	if (wm->mach_ops) {
		mutex_unlock(&wm->codec_mutex);
		return -EINVAL;
	}
	wm->mach_ops = mach_ops;
	mutex_unlock(&wm->codec_mutex);

	return 0;
}
EXPORT_SYMBOL_GPL(wm97xx_register_mach_ops);

void wm97xx_unregister_mach_ops(struct wm97xx *wm)
{
	mutex_lock(&wm->codec_mutex);
	wm->mach_ops = NULL;
	mutex_unlock(&wm->codec_mutex);
}
EXPORT_SYMBOL_GPL(wm97xx_unregister_mach_ops);

static struct device_driver wm97xx_driver = {
	.name =		"wm97xx-ts",
	.bus =		&ac97_bus_type,
	.owner =	THIS_MODULE,
	.probe =	wm97xx_probe,
	.remove =	wm97xx_remove,
	.suspend =	wm97xx_suspend,
	.resume =	wm97xx_resume,
};

static int __init wm97xx_init(void)
{
	return driver_register(&wm97xx_driver);
}

static void __exit wm97xx_exit(void)
{
	driver_unregister(&wm97xx_driver);
}

module_init(wm97xx_init);
module_exit(wm97xx_exit);

/* Module information */
MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
MODULE_DESCRIPTION("WM97xx Core - Touch Screen / AUX ADC / GPIO Driver");
MODULE_LICENSE("GPL");