summaryrefslogtreecommitdiffstats
path: root/sound/core/control_led.c
blob: 25f57c14f294f7ffa7e1fbe045b714ef470aa343 (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
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  LED state routines for driver control interface
 *  Copyright (c) 2021 by Jaroslav Kysela <perex@perex.cz>
 */

#include <linux/slab.h>
#include <linux/module.h>
#include <linux/leds.h>
#include <sound/core.h>
#include <sound/control.h>

MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
MODULE_DESCRIPTION("ALSA control interface to LED trigger code.");
MODULE_LICENSE("GPL");

#define MAX_LED (((SNDRV_CTL_ELEM_ACCESS_MIC_LED - SNDRV_CTL_ELEM_ACCESS_SPK_LED) \
			>> SNDRV_CTL_ELEM_ACCESS_LED_SHIFT) + 1)

enum snd_ctl_led_mode {
	 MODE_FOLLOW_MUTE = 0,
	 MODE_FOLLOW_ROUTE,
	 MODE_OFF,
	 MODE_ON,
};

struct snd_ctl_led_card {
	struct device dev;
	int number;
	struct snd_ctl_led *led;
};

struct snd_ctl_led {
	struct device dev;
	struct list_head controls;
	const char *name;
	unsigned int group;
	enum led_audio trigger_type;
	enum snd_ctl_led_mode mode;
	struct snd_ctl_led_card *cards[SNDRV_CARDS];
};

struct snd_ctl_led_ctl {
	struct list_head list;
	struct snd_card *card;
	unsigned int access;
	struct snd_kcontrol *kctl;
	unsigned int index_offset;
};

static DEFINE_MUTEX(snd_ctl_led_mutex);
static bool snd_ctl_led_card_valid[SNDRV_CARDS];
static struct snd_ctl_led snd_ctl_leds[MAX_LED] = {
	{
		.name = "speaker",
		.group = (SNDRV_CTL_ELEM_ACCESS_SPK_LED >> SNDRV_CTL_ELEM_ACCESS_LED_SHIFT) - 1,
		.trigger_type = LED_AUDIO_MUTE,
		.mode = MODE_FOLLOW_MUTE,
	},
	{
		.name = "mic",
		.group = (SNDRV_CTL_ELEM_ACCESS_MIC_LED >> SNDRV_CTL_ELEM_ACCESS_LED_SHIFT) - 1,
		.trigger_type = LED_AUDIO_MICMUTE,
		.mode = MODE_FOLLOW_MUTE,
	},
};

static void snd_ctl_led_sysfs_add(struct snd_card *card);
static void snd_ctl_led_sysfs_remove(struct snd_card *card);

#define UPDATE_ROUTE(route, cb) \
	do { \
		int route2 = (cb); \
		if (route2 >= 0) \
			route = route < 0 ? route2 : (route | route2); \
	} while (0)

static inline unsigned int access_to_group(unsigned int access)
{
	return ((access & SNDRV_CTL_ELEM_ACCESS_LED_MASK) >>
				SNDRV_CTL_ELEM_ACCESS_LED_SHIFT) - 1;
}

static inline unsigned int group_to_access(unsigned int group)
{
	return (group + 1) << SNDRV_CTL_ELEM_ACCESS_LED_SHIFT;
}

static struct snd_ctl_led *snd_ctl_led_get_by_access(unsigned int access)
{
	unsigned int group = access_to_group(access);
	if (group >= MAX_LED)
		return NULL;
	return &snd_ctl_leds[group];
}

/*
 * A note for callers:
 *   The two static variables info and value are protected using snd_ctl_led_mutex.
 */
static int snd_ctl_led_get(struct snd_ctl_led_ctl *lctl)
{
	static struct snd_ctl_elem_info info;
	static struct snd_ctl_elem_value value;
	struct snd_kcontrol *kctl = lctl->kctl;
	unsigned int i;
	int result;

	memset(&info, 0, sizeof(info));
	info.id = kctl->id;
	info.id.index += lctl->index_offset;
	info.id.numid += lctl->index_offset;
	result = kctl->info(kctl, &info);
	if (result < 0)
		return -1;
	memset(&value, 0, sizeof(value));
	value.id = info.id;
	result = kctl->get(kctl, &value);
	if (result < 0)
		return -1;
	if (info.type == SNDRV_CTL_ELEM_TYPE_BOOLEAN ||
	    info.type == SNDRV_CTL_ELEM_TYPE_INTEGER) {
		for (i = 0; i < info.count; i++)
			if (value.value.integer.value[i] != info.value.integer.min)
				return 1;
	} else if (info.type == SNDRV_CTL_ELEM_TYPE_INTEGER64) {
		for (i = 0; i < info.count; i++)
			if (value.value.integer64.value[i] != info.value.integer64.min)
				return 1;
	}
	return 0;
}

static void snd_ctl_led_set_state(struct snd_card *card, unsigned int access,
				  struct snd_kcontrol *kctl, unsigned int ioff)
{
	struct snd_ctl_led *led;
	struct snd_ctl_led_ctl *lctl;
	int route;
	bool found;

	led = snd_ctl_led_get_by_access(access);
	if (!led)
		return;
	route = -1;
	found = false;
	mutex_lock(&snd_ctl_led_mutex);
	/* the card may not be registered (active) at this point */
	if (card && !snd_ctl_led_card_valid[card->number]) {
		mutex_unlock(&snd_ctl_led_mutex);
		return;
	}
	list_for_each_entry(lctl, &led->controls, list) {
		if (lctl->kctl == kctl && lctl->index_offset == ioff)
			found = true;
		UPDATE_ROUTE(route, snd_ctl_led_get(lctl));
	}
	if (!found && kctl && card) {
		lctl = kzalloc(sizeof(*lctl), GFP_KERNEL);
		if (lctl) {
			lctl->card = card;
			lctl->access = access;
			lctl->kctl = kctl;
			lctl->index_offset = ioff;
			list_add(&lctl->list, &led->controls);
			UPDATE_ROUTE(route, snd_ctl_led_get(lctl));
		}
	}
	mutex_unlock(&snd_ctl_led_mutex);
	switch (led->mode) {
	case MODE_OFF:		route = 1; break;
	case MODE_ON:		route = 0; break;
	case MODE_FOLLOW_ROUTE:	if (route >= 0) route ^= 1; break;
	case MODE_FOLLOW_MUTE:	/* noop */ break;
	}
	if (route >= 0)
		ledtrig_audio_set(led->trigger_type, route ? LED_OFF : LED_ON);
}

static struct snd_ctl_led_ctl *snd_ctl_led_find(struct snd_kcontrol *kctl, unsigned int ioff)
{
	struct list_head *controls;
	struct snd_ctl_led_ctl *lctl;
	unsigned int group;

	for (group = 0; group < MAX_LED; group++) {
		controls = &snd_ctl_leds[group].controls;
		list_for_each_entry(lctl, controls, list)
			if (lctl->kctl == kctl && lctl->index_offset == ioff)
				return lctl;
	}
	return NULL;
}

static unsigned int snd_ctl_led_remove(struct snd_kcontrol *kctl, unsigned int ioff,
				       unsigned int access)
{
	struct snd_ctl_led_ctl *lctl;
	unsigned int ret = 0;

	mutex_lock(&snd_ctl_led_mutex);
	lctl = snd_ctl_led_find(kctl, ioff);
	if (lctl && (access == 0 || access != lctl->access)) {
		ret = lctl->access;
		list_del(&lctl->list);
		kfree(lctl);
	}
	mutex_unlock(&snd_ctl_led_mutex);
	return ret;
}

static void snd_ctl_led_notify(struct snd_card *card, unsigned int mask,
			       struct snd_kcontrol *kctl, unsigned int ioff)
{
	struct snd_kcontrol_volatile *vd;
	unsigned int access, access2;

	if (mask == SNDRV_CTL_EVENT_MASK_REMOVE) {
		access = snd_ctl_led_remove(kctl, ioff, 0);
		if (access)
			snd_ctl_led_set_state(card, access, NULL, 0);
	} else if (mask & SNDRV_CTL_EVENT_MASK_INFO) {
		vd = &kctl->vd[ioff];
		access = vd->access & SNDRV_CTL_ELEM_ACCESS_LED_MASK;
		access2 = snd_ctl_led_remove(kctl, ioff, access);
		if (access2)
			snd_ctl_led_set_state(card, access2, NULL, 0);
		if (access)
			snd_ctl_led_set_state(card, access, kctl, ioff);
	} else if ((mask & (SNDRV_CTL_EVENT_MASK_ADD |
			    SNDRV_CTL_EVENT_MASK_VALUE)) != 0) {
		vd = &kctl->vd[ioff];
		access = vd->access & SNDRV_CTL_ELEM_ACCESS_LED_MASK;
		if (access)
			snd_ctl_led_set_state(card, access, kctl, ioff);
	}
}

static int snd_ctl_led_set_id(int card_number, struct snd_ctl_elem_id *id,
			      unsigned int group, bool set)
{
	struct snd_card *card;
	struct snd_kcontrol *kctl;
	struct snd_kcontrol_volatile *vd;
	unsigned int ioff, access, new_access;
	int err = 0;

	card = snd_card_ref(card_number);
	if (card) {
		down_write(&card->controls_rwsem);
		kctl = snd_ctl_find_id(card, id);
		if (kctl) {
			ioff = snd_ctl_get_ioff(kctl, id);
			vd = &kctl->vd[ioff];
			access = vd->access & SNDRV_CTL_ELEM_ACCESS_LED_MASK;
			if (access != 0 && access != group_to_access(group)) {
				err = -EXDEV;
				goto unlock;
			}
			new_access = vd->access & ~SNDRV_CTL_ELEM_ACCESS_LED_MASK;
			if (set)
				new_access |= group_to_access(group);
			if (new_access != vd->access) {
				vd->access = new_access;
				snd_ctl_led_notify(card, SNDRV_CTL_EVENT_MASK_INFO, kctl, ioff);
			}
		} else {
			err = -ENOENT;
		}
unlock:
		up_write(&card->controls_rwsem);
		snd_card_unref(card);
	} else {
		err = -ENXIO;
	}
	return err;
}

static void snd_ctl_led_refresh(void)
{
	unsigned int group;

	for (group = 0; group < MAX_LED; group++)
		snd_ctl_led_set_state(NULL, group_to_access(group), NULL, 0);
}

static void snd_ctl_led_ctl_destroy(struct snd_ctl_led_ctl *lctl)
{
	list_del(&lctl->list);
	kfree(lctl);
}

static void snd_ctl_led_clean(struct snd_card *card)
{
	unsigned int group;
	struct snd_ctl_led *led;
	struct snd_ctl_led_ctl *lctl;

	for (group = 0; group < MAX_LED; group++) {
		led = &snd_ctl_leds[group];
repeat:
		list_for_each_entry(lctl, &led->controls, list)
			if (!card || lctl->card == card) {
				snd_ctl_led_ctl_destroy(lctl);
				goto repeat;
			}
	}
}

static int snd_ctl_led_reset(int card_number, unsigned int group)
{
	struct snd_card *card;
	struct snd_ctl_led *led;
	struct snd_ctl_led_ctl *lctl;
	struct snd_kcontrol_volatile *vd;
	bool change = false;

	card = snd_card_ref(card_number);
	if (!card)
		return -ENXIO;

	mutex_lock(&snd_ctl_led_mutex);
	if (!snd_ctl_led_card_valid[card_number]) {
		mutex_unlock(&snd_ctl_led_mutex);
		snd_card_unref(card);
		return -ENXIO;
	}
	led = &snd_ctl_leds[group];
repeat:
	list_for_each_entry(lctl, &led->controls, list)
		if (lctl->card == card) {
			vd = &lctl->kctl->vd[lctl->index_offset];
			vd->access &= ~group_to_access(group);
			snd_ctl_led_ctl_destroy(lctl);
			change = true;
			goto repeat;
		}
	mutex_unlock(&snd_ctl_led_mutex);
	if (change)
		snd_ctl_led_set_state(NULL, group_to_access(group), NULL, 0);
	snd_card_unref(card);
	return 0;
}

static void snd_ctl_led_register(struct snd_card *card)
{
	struct snd_kcontrol *kctl;
	unsigned int ioff;

	if (snd_BUG_ON(card->number < 0 ||
		       card->number >= ARRAY_SIZE(snd_ctl_led_card_valid)))
		return;
	mutex_lock(&snd_ctl_led_mutex);
	snd_ctl_led_card_valid[card->number] = true;
	mutex_unlock(&snd_ctl_led_mutex);
	/* the register callback is already called with held card->controls_rwsem */
	list_for_each_entry(kctl, &card->controls, list)
		for (ioff = 0; ioff < kctl->count; ioff++)
			snd_ctl_led_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, kctl, ioff);
	snd_ctl_led_refresh();
	snd_ctl_led_sysfs_add(card);
}

static void snd_ctl_led_disconnect(struct snd_card *card)
{
	snd_ctl_led_sysfs_remove(card);
	mutex_lock(&snd_ctl_led_mutex);
	snd_ctl_led_card_valid[card->number] = false;
	snd_ctl_led_clean(card);
	mutex_unlock(&snd_ctl_led_mutex);
	snd_ctl_led_refresh();
}

/*
 * sysfs
 */

static ssize_t show_mode(struct device *dev,
			 struct device_attribute *attr, char *buf)
{
	struct snd_ctl_led *led = container_of(dev, struct snd_ctl_led, dev);
	const char *str;

	switch (led->mode) {
	case MODE_FOLLOW_MUTE:	str = "follow-mute"; break;
	case MODE_FOLLOW_ROUTE:	str = "follow-route"; break;
	case MODE_ON:		str = "on"; break;
	case MODE_OFF:		str = "off"; break;
	}
	return sprintf(buf, "%s\n", str);
}

static ssize_t store_mode(struct device *dev, struct device_attribute *attr,
			  const char *buf, size_t count)
{
	struct snd_ctl_led *led = container_of(dev, struct snd_ctl_led, dev);
	char _buf[16];
	size_t l = min(count, sizeof(_buf) - 1);
	enum snd_ctl_led_mode mode;

	memcpy(_buf, buf, l);
	_buf[l] = '\0';
	if (strstr(_buf, "mute"))
		mode = MODE_FOLLOW_MUTE;
	else if (strstr(_buf, "route"))
		mode = MODE_FOLLOW_ROUTE;
	else if (strncmp(_buf, "off", 3) == 0 || strncmp(_buf, "0", 1) == 0)
		mode = MODE_OFF;
	else if (strncmp(_buf, "on", 2) == 0 || strncmp(_buf, "1", 1) == 0)
		mode = MODE_ON;
	else
		return count;

	mutex_lock(&snd_ctl_led_mutex);
	led->mode = mode;
	mutex_unlock(&snd_ctl_led_mutex);

	snd_ctl_led_set_state(NULL, group_to_access(led->group), NULL, 0);
	return count;
}

static ssize_t show_brightness(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	struct snd_ctl_led *led = container_of(dev, struct snd_ctl_led, dev);

	return sprintf(buf, "%u\n", ledtrig_audio_get(led->trigger_type));
}

static DEVICE_ATTR(mode, 0644, show_mode, store_mode);
static DEVICE_ATTR(brightness, 0444, show_brightness, NULL);

static struct attribute *snd_ctl_led_dev_attrs[] = {
	&dev_attr_mode.attr,
	&dev_attr_brightness.attr,
	NULL,
};

static const struct attribute_group snd_ctl_led_dev_attr_group = {
	.attrs = snd_ctl_led_dev_attrs,
};

static const struct attribute_group *snd_ctl_led_dev_attr_groups[] = {
	&snd_ctl_led_dev_attr_group,
	NULL,
};

static char *find_eos(char *s)
{
	while (*s && *s != ',')
		s++;
	if (*s)
		s++;
	return s;
}

static char *parse_uint(char *s, unsigned int *val)
{
	unsigned long long res;
	if (kstrtoull(s, 10, &res))
		res = 0;
	*val = res;
	return find_eos(s);
}

static char *parse_string(char *s, char *val, size_t val_size)
{
	if (*s == '"' || *s == '\'') {
		char c = *s;
		s++;
		while (*s && *s != c) {
			if (val_size > 1) {
				*val++ = *s;
				val_size--;
			}
			s++;
		}
	} else {
		while (*s && *s != ',') {
			if (val_size > 1) {
				*val++ = *s;
				val_size--;
			}
			s++;
		}
	}
	*val = '\0';
	if (*s)
		s++;
	return s;
}

static char *parse_iface(char *s, unsigned int *val)
{
	if (!strncasecmp(s, "card", 4))
		*val = SNDRV_CTL_ELEM_IFACE_CARD;
	else if (!strncasecmp(s, "mixer", 5))
		*val = SNDRV_CTL_ELEM_IFACE_MIXER;
	return find_eos(s);
}

/*
 * These types of input strings are accepted:
 *
 *   unsigned integer - numid (equivaled to numid=UINT)
 *   string - basic mixer name (equivalent to iface=MIXER,name=STR)
 *   numid=UINT
 *   [iface=MIXER,][device=UINT,][subdevice=UINT,]name=STR[,index=UINT]
 */
static ssize_t set_led_id(struct snd_ctl_led_card *led_card, const char *buf, size_t count,
			  bool attach)
{
	char buf2[256], *s, *os;
	size_t len = max(sizeof(s) - 1, count);
	struct snd_ctl_elem_id id;
	int err;

	strncpy(buf2, buf, len);
	buf2[len] = '\0';
	memset(&id, 0, sizeof(id));
	id.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
	s = buf2;
	while (*s) {
		os = s;
		if (!strncasecmp(s, "numid=", 6)) {
			s = parse_uint(s + 6, &id.numid);
		} else if (!strncasecmp(s, "iface=", 6)) {
			s = parse_iface(s + 6, &id.iface);
		} else if (!strncasecmp(s, "device=", 7)) {
			s = parse_uint(s + 7, &id.device);
		} else if (!strncasecmp(s, "subdevice=", 10)) {
			s = parse_uint(s + 10, &id.subdevice);
		} else if (!strncasecmp(s, "name=", 5)) {
			s = parse_string(s + 5, id.name, sizeof(id.name));
		} else if (!strncasecmp(s, "index=", 6)) {
			s = parse_uint(s + 6, &id.index);
		} else if (s == buf2) {
			while (*s) {
				if (*s < '0' || *s > '9')
					break;
				s++;
			}
			if (*s == '\0')
				parse_uint(buf2, &id.numid);
			else {
				for (; *s >= ' '; s++);
				*s = '\0';
				strlcpy(id.name, buf2, sizeof(id.name));
			}
			break;
		}
		if (*s == ',')
			s++;
		if (s == os)
			break;
	}

	err = snd_ctl_led_set_id(led_card->number, &id, led_card->led->group, attach);
	if (err < 0)
		return err;

	return count;
}

static ssize_t parse_attach(struct device *dev, struct device_attribute *attr,
			    const char *buf, size_t count)
{
	struct snd_ctl_led_card *led_card = container_of(dev, struct snd_ctl_led_card, dev);
	return set_led_id(led_card, buf, count, true);
}

static ssize_t parse_detach(struct device *dev, struct device_attribute *attr,
			    const char *buf, size_t count)
{
	struct snd_ctl_led_card *led_card = container_of(dev, struct snd_ctl_led_card, dev);
	return set_led_id(led_card, buf, count, false);
}

static ssize_t ctl_reset(struct device *dev, struct device_attribute *attr,
			 const char *buf, size_t count)
{
	struct snd_ctl_led_card *led_card = container_of(dev, struct snd_ctl_led_card, dev);
	int err;

	if (count > 0 && buf[0] == '1') {
		err = snd_ctl_led_reset(led_card->number, led_card->led->group);
		if (err < 0)
			return err;
	}
	return count;
}

static ssize_t ctl_list(struct device *dev,
			struct device_attribute *attr, char *buf)
{
	struct snd_ctl_led_card *led_card = container_of(dev, struct snd_ctl_led_card, dev);
	struct snd_card *card;
	struct snd_ctl_led_ctl *lctl;
	char *buf2 = buf;
	size_t l;

	card = snd_card_ref(led_card->number);
	if (!card)
		return -ENXIO;
	down_read(&card->controls_rwsem);
	mutex_lock(&snd_ctl_led_mutex);
	if (snd_ctl_led_card_valid[led_card->number]) {
		list_for_each_entry(lctl, &led_card->led->controls, list)
			if (lctl->card == card) {
				if (buf2 - buf > PAGE_SIZE - 16)
					break;
				if (buf2 != buf)
					*buf2++ = ' ';
				l = scnprintf(buf2, 15, "%u",
						lctl->kctl->id.numid +
							lctl->index_offset);
				buf2[l] = '\0';
				buf2 += l + 1;
			}
	}
	mutex_unlock(&snd_ctl_led_mutex);
	up_read(&card->controls_rwsem);
	snd_card_unref(card);
	return buf2 - buf;
}

static DEVICE_ATTR(attach, 0200, NULL, parse_attach);
static DEVICE_ATTR(detach, 0200, NULL, parse_detach);
static DEVICE_ATTR(reset, 0200, NULL, ctl_reset);
static DEVICE_ATTR(list, 0444, ctl_list, NULL);

static struct attribute *snd_ctl_led_card_attrs[] = {
	&dev_attr_attach.attr,
	&dev_attr_detach.attr,
	&dev_attr_reset.attr,
	&dev_attr_list.attr,
	NULL,
};

static const struct attribute_group snd_ctl_led_card_attr_group = {
	.attrs = snd_ctl_led_card_attrs,
};

static const struct attribute_group *snd_ctl_led_card_attr_groups[] = {
	&snd_ctl_led_card_attr_group,
	NULL,
};

static struct device snd_ctl_led_dev;

static void snd_ctl_led_sysfs_add(struct snd_card *card)
{
	unsigned int group;
	struct snd_ctl_led_card *led_card;
	struct snd_ctl_led *led;
	char link_name[32];

	for (group = 0; group < MAX_LED; group++) {
		led = &snd_ctl_leds[group];
		led_card = kzalloc(sizeof(*led_card), GFP_KERNEL);
		if (!led_card)
			goto cerr2;
		led_card->number = card->number;
		led_card->led = led;
		device_initialize(&led_card->dev);
		if (dev_set_name(&led_card->dev, "card%d", card->number) < 0)
			goto cerr;
		led_card->dev.parent = &led->dev;
		led_card->dev.groups = snd_ctl_led_card_attr_groups;
		if (device_add(&led_card->dev))
			goto cerr;
		led->cards[card->number] = led_card;
		snprintf(link_name, sizeof(link_name), "led-%s", led->name);
		WARN(sysfs_create_link(&card->ctl_dev.kobj, &led_card->dev.kobj, link_name),
			"can't create symlink to controlC%i device\n", card->number);
		WARN(sysfs_create_link(&led_card->dev.kobj, &card->card_dev.kobj, "card"),
			"can't create symlink to card%i\n", card->number);

		continue;
cerr:
		put_device(&led_card->dev);
cerr2:
		printk(KERN_ERR "snd_ctl_led: unable to add card%d", card->number);
		kfree(led_card);
	}
}

static void snd_ctl_led_sysfs_remove(struct snd_card *card)
{
	unsigned int group;
	struct snd_ctl_led_card *led_card;
	struct snd_ctl_led *led;
	char link_name[32];

	for (group = 0; group < MAX_LED; group++) {
		led = &snd_ctl_leds[group];
		led_card = led->cards[card->number];
		if (!led_card)
			continue;
		snprintf(link_name, sizeof(link_name), "led-%s", led->name);
		sysfs_remove_link(&card->ctl_dev.kobj, link_name);
		sysfs_remove_link(&led_card->dev.kobj, "card");
		device_del(&led_card->dev);
		kfree(led_card);
		led->cards[card->number] = NULL;
	}
}

/*
 * Control layer registration
 */
static struct snd_ctl_layer_ops snd_ctl_led_lops = {
	.module_name = SND_CTL_LAYER_MODULE_LED,
	.lregister = snd_ctl_led_register,
	.ldisconnect = snd_ctl_led_disconnect,
	.lnotify = snd_ctl_led_notify,
};

static int __init snd_ctl_led_init(void)
{
	struct snd_ctl_led *led;
	unsigned int group;

	device_initialize(&snd_ctl_led_dev);
	snd_ctl_led_dev.class = sound_class;
	dev_set_name(&snd_ctl_led_dev, "ctl-led");
	if (device_add(&snd_ctl_led_dev)) {
		put_device(&snd_ctl_led_dev);
		return -ENOMEM;
	}
	for (group = 0; group < MAX_LED; group++) {
		led = &snd_ctl_leds[group];
		INIT_LIST_HEAD(&led->controls);
		device_initialize(&led->dev);
		led->dev.parent = &snd_ctl_led_dev;
		led->dev.groups = snd_ctl_led_dev_attr_groups;
		dev_set_name(&led->dev, led->name);
		if (device_add(&led->dev)) {
			put_device(&led->dev);
			for (; group > 0; group--) {
				led = &snd_ctl_leds[group - 1];
				device_del(&led->dev);
			}
			device_del(&snd_ctl_led_dev);
			return -ENOMEM;
		}
	}
	snd_ctl_register_layer(&snd_ctl_led_lops);
	return 0;
}

static void __exit snd_ctl_led_exit(void)
{
	struct snd_ctl_led *led;
	struct snd_card *card;
	unsigned int group, card_number;

	snd_ctl_disconnect_layer(&snd_ctl_led_lops);
	for (card_number = 0; card_number < SNDRV_CARDS; card_number++) {
		if (!snd_ctl_led_card_valid[card_number])
			continue;
		card = snd_card_ref(card_number);
		if (card) {
			snd_ctl_led_sysfs_remove(card);
			snd_card_unref(card);
		}
	}
	for (group = 0; group < MAX_LED; group++) {
		led = &snd_ctl_leds[group];
		device_del(&led->dev);
	}
	device_del(&snd_ctl_led_dev);
	snd_ctl_led_clean(NULL);
}

module_init(snd_ctl_led_init)
module_exit(snd_ctl_led_exit)