summaryrefslogtreecommitdiffstats
path: root/drivers/extcon/extcon.c
blob: 862334e69cf13d4a3a4aa500b04bd873b3237c2f (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
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
/*
 *  drivers/extcon/extcon.c - External Connector (extcon) framework.
 *
 *  External connector (extcon) class driver
 *
 * Copyright (C) 2015 Samsung Electronics
 * Author: Chanwoo Choi <cw00.choi@samsung.com>
 *
 * Copyright (C) 2012 Samsung Electronics
 * Author: Donggeun Kim <dg77.kim@samsung.com>
 * Author: MyungJoo Ham <myungjoo.ham@samsung.com>
 *
 * based on android/drivers/switch/switch_class.c
 * Copyright (C) 2008 Google, Inc.
 * Author: Mike Lockwood <lockwood@android.com>
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/err.h>
#include <linux/extcon.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/sysfs.h>

#define SUPPORTED_CABLE_MAX	32
#define CABLE_NAME_MAX		30

static const char *extcon_name[] =  {
	[EXTCON_NONE]			= "NONE",

	/* USB external connector */
	[EXTCON_USB]			= "USB",
	[EXTCON_USB_HOST]		= "USB-HOST",

	/* Charging external connector */
	[EXTCON_CHG_USB_SDP]		= "SDP",
	[EXTCON_CHG_USB_DCP]		= "DCP",
	[EXTCON_CHG_USB_CDP]		= "CDP",
	[EXTCON_CHG_USB_ACA]		= "ACA",
	[EXTCON_CHG_USB_FAST]		= "FAST-CHARGER",
	[EXTCON_CHG_USB_SLOW]		= "SLOW-CHARGER",

	/* Jack external connector */
	[EXTCON_JACK_MICROPHONE]	= "MICROPHONE",
	[EXTCON_JACK_HEADPHONE]		= "HEADPHONE",
	[EXTCON_JACK_LINE_IN]		= "LINE-IN",
	[EXTCON_JACK_LINE_OUT]		= "LINE-OUT",
	[EXTCON_JACK_VIDEO_IN]		= "VIDEO-IN",
	[EXTCON_JACK_VIDEO_OUT]		= "VIDEO-OUT",
	[EXTCON_JACK_SPDIF_IN]		= "SPDIF-IN",
	[EXTCON_JACK_SPDIF_OUT]		= "SPDIF-OUT",

	/* Display external connector */
	[EXTCON_DISP_HDMI]		= "HDMI",
	[EXTCON_DISP_MHL]		= "MHL",
	[EXTCON_DISP_DVI]		= "DVI",
	[EXTCON_DISP_VGA]		= "VGA",

	/* Miscellaneous external connector */
	[EXTCON_DOCK]			= "DOCK",
	[EXTCON_JIG]			= "JIG",
	[EXTCON_MECHANICAL]		= "MECHANICAL",

	NULL,
};

/**
 * struct extcon_cable - An internal data for each cable of extcon device.
 * @edev:		The extcon device
 * @cable_index:	Index of this cable in the edev
 * @attr_g:		Attribute group for the cable
 * @attr_name:		"name" sysfs entry
 * @attr_state:		"state" sysfs entry
 * @attrs:		Array pointing to attr_name and attr_state for attr_g
 */
struct extcon_cable {
	struct extcon_dev *edev;
	int cable_index;

	struct attribute_group attr_g;
	struct device_attribute attr_name;
	struct device_attribute attr_state;

	struct attribute *attrs[3]; /* to be fed to attr_g.attrs */
};

static struct class *extcon_class;
#if defined(CONFIG_ANDROID)
static struct class_compat *switch_class;
#endif /* CONFIG_ANDROID */

static LIST_HEAD(extcon_dev_list);
static DEFINE_MUTEX(extcon_dev_list_lock);

/**
 * check_mutually_exclusive - Check if new_state violates mutually_exclusive
 *			      condition.
 * @edev:	the extcon device
 * @new_state:	new cable attach status for @edev
 *
 * Returns 0 if nothing violates. Returns the index + 1 for the first
 * violated condition.
 */
static int check_mutually_exclusive(struct extcon_dev *edev, u32 new_state)
{
	int i = 0;

	if (!edev->mutually_exclusive)
		return 0;

	for (i = 0; edev->mutually_exclusive[i]; i++) {
		int weight;
		u32 correspondants = new_state & edev->mutually_exclusive[i];

		/* calculate the total number of bits set */
		weight = hweight32(correspondants);
		if (weight > 1)
			return i + 1;
	}

	return 0;
}

static int find_cable_index_by_id(struct extcon_dev *edev, const unsigned int id)
{
	int i;

	/* Find the the index of extcon cable in edev->supported_cable */
	for (i = 0; i < edev->max_supported; i++) {
		if (edev->supported_cable[i] == id)
			return i;
	}

	return -EINVAL;
}

static bool is_extcon_changed(u32 prev, u32 new, int idx, bool *attached)
{
	if (((prev >> idx) & 0x1) != ((new >> idx) & 0x1)) {
		*attached = ((new >> idx) & 0x1) ? true : false;
		return true;
	}

	return false;
}

static ssize_t state_show(struct device *dev, struct device_attribute *attr,
			  char *buf)
{
	int i, count = 0;
	struct extcon_dev *edev = dev_get_drvdata(dev);

	if (edev->max_supported == 0)
		return sprintf(buf, "%u\n", edev->state);

	for (i = 0; i < edev->max_supported; i++) {
		count += sprintf(buf + count, "%s=%d\n",
				extcon_name[edev->supported_cable[i]],
				 !!(edev->state & (1 << i)));
	}

	return count;
}

static ssize_t state_store(struct device *dev, struct device_attribute *attr,
			   const char *buf, size_t count)
{
	u32 state;
	ssize_t ret = 0;
	struct extcon_dev *edev = dev_get_drvdata(dev);

	ret = sscanf(buf, "0x%x", &state);
	if (ret == 0)
		ret = -EINVAL;
	else
		ret = extcon_set_state(edev, state);

	if (ret < 0)
		return ret;

	return count;
}
static DEVICE_ATTR_RW(state);

static ssize_t name_show(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	struct extcon_dev *edev = dev_get_drvdata(dev);

	return sprintf(buf, "%s\n", edev->name);
}
static DEVICE_ATTR_RO(name);

static ssize_t cable_name_show(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	struct extcon_cable *cable = container_of(attr, struct extcon_cable,
						  attr_name);
	int i = cable->cable_index;

	return sprintf(buf, "%s\n",
			extcon_name[cable->edev->supported_cable[i]]);
}

static ssize_t cable_state_show(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	struct extcon_cable *cable = container_of(attr, struct extcon_cable,
						  attr_state);

	int i = cable->cable_index;

	return sprintf(buf, "%d\n",
		       extcon_get_cable_state_(cable->edev,
					       cable->edev->supported_cable[i]));
}

/**
 * extcon_update_state() - Update the cable attach states of the extcon device
 *			   only for the masked bits.
 * @edev:	the extcon device
 * @mask:	the bit mask to designate updated bits.
 * @state:	new cable attach status for @edev
 *
 * Changing the state sends uevent with environment variable containing
 * the name of extcon device (envp[0]) and the state output (envp[1]).
 * Tizen uses this format for extcon device to get events from ports.
 * Android uses this format as well.
 *
 * Note that the notifier provides which bits are changed in the state
 * variable with the val parameter (second) to the callback.
 */
int extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state)
{
	char name_buf[120];
	char state_buf[120];
	char *prop_buf;
	char *envp[3];
	int env_offset = 0;
	int length;
	int index;
	unsigned long flags;
	bool attached;

	if (!edev)
		return -EINVAL;

	spin_lock_irqsave(&edev->lock, flags);

	if (edev->state != ((edev->state & ~mask) | (state & mask))) {
		u32 old_state;

		if (check_mutually_exclusive(edev, (edev->state & ~mask) |
						   (state & mask))) {
			spin_unlock_irqrestore(&edev->lock, flags);
			return -EPERM;
		}

		old_state = edev->state;
		edev->state &= ~mask;
		edev->state |= state & mask;

		for (index = 0; index < edev->max_supported; index++) {
			if (is_extcon_changed(old_state, edev->state, index,
					      &attached))
				raw_notifier_call_chain(&edev->nh[index],
							attached, edev);
		}

		/* This could be in interrupt handler */
		prop_buf = (char *)get_zeroed_page(GFP_ATOMIC);
		if (prop_buf) {
			length = name_show(&edev->dev, NULL, prop_buf);
			if (length > 0) {
				if (prop_buf[length - 1] == '\n')
					prop_buf[length - 1] = 0;
				snprintf(name_buf, sizeof(name_buf),
					"NAME=%s", prop_buf);
				envp[env_offset++] = name_buf;
			}
			length = state_show(&edev->dev, NULL, prop_buf);
			if (length > 0) {
				if (prop_buf[length - 1] == '\n')
					prop_buf[length - 1] = 0;
				snprintf(state_buf, sizeof(state_buf),
					"STATE=%s", prop_buf);
				envp[env_offset++] = state_buf;
			}
			envp[env_offset] = NULL;
			/* Unlock early before uevent */
			spin_unlock_irqrestore(&edev->lock, flags);

			kobject_uevent_env(&edev->dev.kobj, KOBJ_CHANGE, envp);
			free_page((unsigned long)prop_buf);
		} else {
			/* Unlock early before uevent */
			spin_unlock_irqrestore(&edev->lock, flags);

			dev_err(&edev->dev, "out of memory in extcon_set_state\n");
			kobject_uevent(&edev->dev.kobj, KOBJ_CHANGE);
		}
	} else {
		/* No changes */
		spin_unlock_irqrestore(&edev->lock, flags);
	}

	return 0;
}
EXPORT_SYMBOL_GPL(extcon_update_state);

/**
 * extcon_set_state() - Set the cable attach states of the extcon device.
 * @edev:	the extcon device
 * @state:	new cable attach status for @edev
 *
 * Note that notifier provides which bits are changed in the state
 * variable with the val parameter (second) to the callback.
 */
int extcon_set_state(struct extcon_dev *edev, u32 state)
{
	if (!edev)
		return -EINVAL;

	return extcon_update_state(edev, 0xffffffff, state);
}
EXPORT_SYMBOL_GPL(extcon_set_state);

/**
 * extcon_get_cable_state_() - Get the status of a specific cable.
 * @edev:	the extcon device that has the cable.
 * @id:		the unique id of each external connector in extcon enumeration.
 */
int extcon_get_cable_state_(struct extcon_dev *edev, const unsigned int id)
{
	int index;

	if (!edev)
		return -EINVAL;

	index = find_cable_index_by_id(edev, id);
	if (index < 0)
		return index;

	if (edev->max_supported && edev->max_supported <= index)
		return -EINVAL;

	return !!(edev->state & (1 << index));
}
EXPORT_SYMBOL_GPL(extcon_get_cable_state_);

/**
 * extcon_set_cable_state_() - Set the status of a specific cable.
 * @edev:		the extcon device that has the cable.
 * @id:			the unique id of each external connector
 *			in extcon enumeration.
 * @state:		the new cable status. The default semantics is
 *			true: attached / false: detached.
 */
int extcon_set_cable_state_(struct extcon_dev *edev, unsigned int id,
				bool cable_state)
{
	u32 state;
	int index;

	if (!edev)
		return -EINVAL;

	index = find_cable_index_by_id(edev, id);
	if (index < 0)
		return index;

	if (edev->max_supported && edev->max_supported <= index)
		return -EINVAL;

	state = cable_state ? (1 << index) : 0;
	return extcon_update_state(edev, 1 << index, state);
}
EXPORT_SYMBOL_GPL(extcon_set_cable_state_);

/**
 * extcon_get_extcon_dev() - Get the extcon device instance from the name
 * @extcon_name:	The extcon name provided with extcon_dev_register()
 */
struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
{
	struct extcon_dev *sd;

	if (!extcon_name)
		return ERR_PTR(-EINVAL);

	mutex_lock(&extcon_dev_list_lock);
	list_for_each_entry(sd, &extcon_dev_list, entry) {
		if (!strcmp(sd->name, extcon_name))
			goto out;
	}
	sd = NULL;
out:
	mutex_unlock(&extcon_dev_list_lock);
	return sd;
}
EXPORT_SYMBOL_GPL(extcon_get_extcon_dev);

/**
 * extcon_register_notifier() - Register a notifiee to get notified by
 *				any attach status changes from the extcon.
 * @edev:	the extcon device that has the external connecotr.
 * @id:		the unique id of each external connector in extcon enumeration.
 * @nb:		a notifier block to be registered.
 *
 * Note that the second parameter given to the callback of nb (val) is
 * "old_state", not the current state. The current state can be retrieved
 * by looking at the third pameter (edev pointer)'s state value.
 */
int extcon_register_notifier(struct extcon_dev *edev, unsigned int id,
			     struct notifier_block *nb)
{
	unsigned long flags;
	int ret, idx;

	if (!nb)
		return -EINVAL;

	if (edev) {
		idx = find_cable_index_by_id(edev, id);
		if (idx < 0)
			return idx;

		spin_lock_irqsave(&edev->lock, flags);
		ret = raw_notifier_chain_register(&edev->nh[idx], nb);
		spin_unlock_irqrestore(&edev->lock, flags);
	} else {
		struct extcon_dev *extd;

		mutex_lock(&extcon_dev_list_lock);
		list_for_each_entry(extd, &extcon_dev_list, entry) {
			idx = find_cable_index_by_id(extd, id);
			if (idx >= 0)
				break;
		}
		mutex_unlock(&extcon_dev_list_lock);

		if (idx >= 0) {
			edev = extd;
			return extcon_register_notifier(extd, id, nb);
		} else {
			ret = -ENODEV;
		}
	}

	return ret;
}
EXPORT_SYMBOL_GPL(extcon_register_notifier);

/**
 * extcon_unregister_notifier() - Unregister a notifiee from the extcon device.
 * @edev:	the extcon device that has the external connecotr.
 * @id:		the unique id of each external connector in extcon enumeration.
 * @nb:		a notifier block to be registered.
 */
int extcon_unregister_notifier(struct extcon_dev *edev, unsigned int id,
				struct notifier_block *nb)
{
	unsigned long flags;
	int ret, idx;

	if (!edev || !nb)
		return -EINVAL;

	idx = find_cable_index_by_id(edev, id);
	if (idx < 0)
		return idx;

	spin_lock_irqsave(&edev->lock, flags);
	ret = raw_notifier_chain_unregister(&edev->nh[idx], nb);
	spin_unlock_irqrestore(&edev->lock, flags);

	return ret;
}
EXPORT_SYMBOL_GPL(extcon_unregister_notifier);

static struct attribute *extcon_attrs[] = {
	&dev_attr_state.attr,
	&dev_attr_name.attr,
	NULL,
};
ATTRIBUTE_GROUPS(extcon);

static int create_extcon_class(void)
{
	if (!extcon_class) {
		extcon_class = class_create(THIS_MODULE, "extcon");
		if (IS_ERR(extcon_class))
			return PTR_ERR(extcon_class);
		extcon_class->dev_groups = extcon_groups;

#if defined(CONFIG_ANDROID)
		switch_class = class_compat_register("switch");
		if (WARN(!switch_class, "cannot allocate"))
			return -ENOMEM;
#endif /* CONFIG_ANDROID */
	}

	return 0;
}

static void extcon_dev_release(struct device *dev)
{
}

static const char *muex_name = "mutually_exclusive";
static void dummy_sysfs_dev_release(struct device *dev)
{
}

/*
 * extcon_dev_allocate() - Allocate the memory of extcon device.
 * @supported_cable:	Array of supported extcon ending with EXTCON_NONE.
 *			If supported_cable is NULL, cable name related APIs
 *			are disabled.
 *
 * This function allocates the memory for extcon device without allocating
 * memory in each extcon provider driver and initialize default setting for
 * extcon device.
 *
 * Return the pointer of extcon device if success or ERR_PTR(err) if fail
 */
struct extcon_dev *extcon_dev_allocate(const unsigned int *supported_cable)
{
	struct extcon_dev *edev;

	if (!supported_cable)
		return ERR_PTR(-EINVAL);

	edev = kzalloc(sizeof(*edev), GFP_KERNEL);
	if (!edev)
		return ERR_PTR(-ENOMEM);

	edev->max_supported = 0;
	edev->supported_cable = supported_cable;

	return edev;
}

/*
 * extcon_dev_free() - Free the memory of extcon device.
 * @edev:	the extcon device to free
 */
void extcon_dev_free(struct extcon_dev *edev)
{
	kfree(edev);
}
EXPORT_SYMBOL_GPL(extcon_dev_free);

/**
 * extcon_dev_register() - Register a new extcon device
 * @edev	: the new extcon device (should be allocated before calling)
 *
 * Among the members of edev struct, please set the "user initializing data"
 * in any case and set the "optional callbacks" if required. However, please
 * do not set the values of "internal data", which are initialized by
 * this function.
 */
int extcon_dev_register(struct extcon_dev *edev)
{
	int ret, index = 0;
	static atomic_t edev_no = ATOMIC_INIT(-1);

	if (!extcon_class) {
		ret = create_extcon_class();
		if (ret < 0)
			return ret;
	}

	if (!edev || !edev->supported_cable)
		return -EINVAL;

	for (; edev->supported_cable[index] != EXTCON_NONE; index++);

	edev->max_supported = index;
	if (index > SUPPORTED_CABLE_MAX) {
		dev_err(&edev->dev,
			"exceed the maximum number of supported cables\n");
		return -EINVAL;
	}

	edev->dev.class = extcon_class;
	edev->dev.release = extcon_dev_release;

	edev->name = dev_name(edev->dev.parent);
	if (IS_ERR_OR_NULL(edev->name)) {
		dev_err(&edev->dev,
			"extcon device name is null\n");
		return -EINVAL;
	}
	dev_set_name(&edev->dev, "extcon%lu",
			(unsigned long)atomic_inc_return(&edev_no));

	if (edev->max_supported) {
		char buf[10];
		char *str;
		struct extcon_cable *cable;

		edev->cables = kzalloc(sizeof(struct extcon_cable) *
				       edev->max_supported, GFP_KERNEL);
		if (!edev->cables) {
			ret = -ENOMEM;
			goto err_sysfs_alloc;
		}
		for (index = 0; index < edev->max_supported; index++) {
			cable = &edev->cables[index];

			snprintf(buf, 10, "cable.%d", index);
			str = kzalloc(sizeof(char) * (strlen(buf) + 1),
				      GFP_KERNEL);
			if (!str) {
				for (index--; index >= 0; index--) {
					cable = &edev->cables[index];
					kfree(cable->attr_g.name);
				}
				ret = -ENOMEM;

				goto err_alloc_cables;
			}
			strcpy(str, buf);

			cable->edev = edev;
			cable->cable_index = index;
			cable->attrs[0] = &cable->attr_name.attr;
			cable->attrs[1] = &cable->attr_state.attr;
			cable->attrs[2] = NULL;
			cable->attr_g.name = str;
			cable->attr_g.attrs = cable->attrs;

			sysfs_attr_init(&cable->attr_name.attr);
			cable->attr_name.attr.name = "name";
			cable->attr_name.attr.mode = 0444;
			cable->attr_name.show = cable_name_show;

			sysfs_attr_init(&cable->attr_state.attr);
			cable->attr_state.attr.name = "state";
			cable->attr_state.attr.mode = 0444;
			cable->attr_state.show = cable_state_show;
		}
	}

	if (edev->max_supported && edev->mutually_exclusive) {
		char buf[80];
		char *name;

		/* Count the size of mutually_exclusive array */
		for (index = 0; edev->mutually_exclusive[index]; index++)
			;

		edev->attrs_muex = kzalloc(sizeof(struct attribute *) *
					   (index + 1), GFP_KERNEL);
		if (!edev->attrs_muex) {
			ret = -ENOMEM;
			goto err_muex;
		}

		edev->d_attrs_muex = kzalloc(sizeof(struct device_attribute) *
					     index, GFP_KERNEL);
		if (!edev->d_attrs_muex) {
			ret = -ENOMEM;
			kfree(edev->attrs_muex);
			goto err_muex;
		}

		for (index = 0; edev->mutually_exclusive[index]; index++) {
			sprintf(buf, "0x%x", edev->mutually_exclusive[index]);
			name = kzalloc(sizeof(char) * (strlen(buf) + 1),
				       GFP_KERNEL);
			if (!name) {
				for (index--; index >= 0; index--) {
					kfree(edev->d_attrs_muex[index].attr.
					      name);
				}
				kfree(edev->d_attrs_muex);
				kfree(edev->attrs_muex);
				ret = -ENOMEM;
				goto err_muex;
			}
			strcpy(name, buf);
			sysfs_attr_init(&edev->d_attrs_muex[index].attr);
			edev->d_attrs_muex[index].attr.name = name;
			edev->d_attrs_muex[index].attr.mode = 0000;
			edev->attrs_muex[index] = &edev->d_attrs_muex[index]
							.attr;
		}
		edev->attr_g_muex.name = muex_name;
		edev->attr_g_muex.attrs = edev->attrs_muex;

	}

	if (edev->max_supported) {
		edev->extcon_dev_type.groups =
			kzalloc(sizeof(struct attribute_group *) *
				(edev->max_supported + 2), GFP_KERNEL);
		if (!edev->extcon_dev_type.groups) {
			ret = -ENOMEM;
			goto err_alloc_groups;
		}

		edev->extcon_dev_type.name = dev_name(&edev->dev);
		edev->extcon_dev_type.release = dummy_sysfs_dev_release;

		for (index = 0; index < edev->max_supported; index++)
			edev->extcon_dev_type.groups[index] =
				&edev->cables[index].attr_g;
		if (edev->mutually_exclusive)
			edev->extcon_dev_type.groups[index] =
				&edev->attr_g_muex;

		edev->dev.type = &edev->extcon_dev_type;
	}

	ret = device_register(&edev->dev);
	if (ret) {
		put_device(&edev->dev);
		goto err_dev;
	}
#if defined(CONFIG_ANDROID)
	if (switch_class)
		ret = class_compat_create_link(switch_class, &edev->dev, NULL);
#endif /* CONFIG_ANDROID */

	spin_lock_init(&edev->lock);

	edev->nh = devm_kzalloc(&edev->dev,
			sizeof(*edev->nh) * edev->max_supported, GFP_KERNEL);
	if (!edev->nh) {
		ret = -ENOMEM;
		goto err_dev;
	}

	for (index = 0; index < edev->max_supported; index++)
		RAW_INIT_NOTIFIER_HEAD(&edev->nh[index]);

	dev_set_drvdata(&edev->dev, edev);
	edev->state = 0;

	mutex_lock(&extcon_dev_list_lock);
	list_add(&edev->entry, &extcon_dev_list);
	mutex_unlock(&extcon_dev_list_lock);

	return 0;

err_dev:
	if (edev->max_supported)
		kfree(edev->extcon_dev_type.groups);
err_alloc_groups:
	if (edev->max_supported && edev->mutually_exclusive) {
		for (index = 0; edev->mutually_exclusive[index]; index++)
			kfree(edev->d_attrs_muex[index].attr.name);
		kfree(edev->d_attrs_muex);
		kfree(edev->attrs_muex);
	}
err_muex:
	for (index = 0; index < edev->max_supported; index++)
		kfree(edev->cables[index].attr_g.name);
err_alloc_cables:
	if (edev->max_supported)
		kfree(edev->cables);
err_sysfs_alloc:
	return ret;
}
EXPORT_SYMBOL_GPL(extcon_dev_register);

/**
 * extcon_dev_unregister() - Unregister the extcon device.
 * @edev:	the extcon device instance to be unregistered.
 *
 * Note that this does not call kfree(edev) because edev was not allocated
 * by this class.
 */
void extcon_dev_unregister(struct extcon_dev *edev)
{
	int index;

	if (!edev)
		return;

	mutex_lock(&extcon_dev_list_lock);
	list_del(&edev->entry);
	mutex_unlock(&extcon_dev_list_lock);

	if (IS_ERR_OR_NULL(get_device(&edev->dev))) {
		dev_err(&edev->dev, "Failed to unregister extcon_dev (%s)\n",
				dev_name(&edev->dev));
		return;
	}

	device_unregister(&edev->dev);

	if (edev->mutually_exclusive && edev->max_supported) {
		for (index = 0; edev->mutually_exclusive[index];
				index++)
			kfree(edev->d_attrs_muex[index].attr.name);
		kfree(edev->d_attrs_muex);
		kfree(edev->attrs_muex);
	}

	for (index = 0; index < edev->max_supported; index++)
		kfree(edev->cables[index].attr_g.name);

	if (edev->max_supported) {
		kfree(edev->extcon_dev_type.groups);
		kfree(edev->cables);
	}

#if defined(CONFIG_ANDROID)
	if (switch_class)
		class_compat_remove_link(switch_class, &edev->dev, NULL);
#endif
	put_device(&edev->dev);
}
EXPORT_SYMBOL_GPL(extcon_dev_unregister);

#ifdef CONFIG_OF
/*
 * extcon_get_edev_by_phandle - Get the extcon device from devicetree
 * @dev - instance to the given device
 * @index - index into list of extcon_dev
 *
 * return the instance of extcon device
 */
struct extcon_dev *extcon_get_edev_by_phandle(struct device *dev, int index)
{
	struct device_node *node;
	struct extcon_dev *edev;

	if (!dev)
		return ERR_PTR(-EINVAL);

	if (!dev->of_node) {
		dev_err(dev, "device does not have a device node entry\n");
		return ERR_PTR(-EINVAL);
	}

	node = of_parse_phandle(dev->of_node, "extcon", index);
	if (!node) {
		dev_err(dev, "failed to get phandle in %s node\n",
			dev->of_node->full_name);
		return ERR_PTR(-ENODEV);
	}

	mutex_lock(&extcon_dev_list_lock);
	list_for_each_entry(edev, &extcon_dev_list, entry) {
		if (edev->dev.parent && edev->dev.parent->of_node == node) {
			mutex_unlock(&extcon_dev_list_lock);
			return edev;
		}
	}
	mutex_unlock(&extcon_dev_list_lock);

	return ERR_PTR(-EPROBE_DEFER);
}
#else
struct extcon_dev *extcon_get_edev_by_phandle(struct device *dev, int index)
{
	return ERR_PTR(-ENOSYS);
}
#endif /* CONFIG_OF */
EXPORT_SYMBOL_GPL(extcon_get_edev_by_phandle);

/**
 * extcon_get_edev_name() - Get the name of the extcon device.
 * @edev:	the extcon device
 */
const char *extcon_get_edev_name(struct extcon_dev *edev)
{
	return !edev ? NULL : edev->name;
}

static int __init extcon_class_init(void)
{
	return create_extcon_class();
}
module_init(extcon_class_init);

static void __exit extcon_class_exit(void)
{
#if defined(CONFIG_ANDROID)
	class_compat_unregister(switch_class);
#endif
	class_destroy(extcon_class);
}
module_exit(extcon_class_exit);

MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
MODULE_AUTHOR("Donggeun Kim <dg77.kim@samsung.com>");
MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
MODULE_DESCRIPTION("External connector (extcon) class driver");
MODULE_LICENSE("GPL");