2 * Routines for driver control interface
3 * Copyright (c) by Jaroslav Kysela <perex@perex.cz>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 #include <linux/threads.h>
23 #include <linux/interrupt.h>
24 #include <linux/slab.h>
25 #include <linux/vmalloc.h>
26 #include <linux/time.h>
27 #include <sound/core.h>
28 #include <sound/minors.h>
29 #include <sound/info.h>
30 #include <sound/control.h>
32 /* max number of user-defined controls */
33 #define MAX_USER_CONTROLS 32
34 #define MAX_CONTROL_COUNT 1028
36 struct snd_kctl_ioctl
{
37 struct list_head list
; /* list of all ioctls */
38 snd_kctl_ioctl_func_t fioctl
;
41 static DECLARE_RWSEM(snd_ioctl_rwsem
);
42 static LIST_HEAD(snd_control_ioctls
);
44 static LIST_HEAD(snd_control_compat_ioctls
);
47 static int snd_ctl_open(struct inode
*inode
, struct file
*file
)
50 struct snd_card
*card
;
51 struct snd_ctl_file
*ctl
;
54 err
= nonseekable_open(inode
, file
);
58 card
= snd_lookup_minor_data(iminor(inode
), SNDRV_DEVICE_TYPE_CONTROL
);
63 err
= snd_card_file_add(card
, file
);
68 if (!try_module_get(card
->module
)) {
72 ctl
= kzalloc(sizeof(*ctl
), GFP_KERNEL
);
77 INIT_LIST_HEAD(&ctl
->events
);
78 init_waitqueue_head(&ctl
->change_sleep
);
79 spin_lock_init(&ctl
->read_lock
);
81 ctl
->prefer_pcm_subdevice
= -1;
82 ctl
->prefer_rawmidi_subdevice
= -1;
83 ctl
->pid
= get_pid(task_pid(current
));
84 file
->private_data
= ctl
;
85 write_lock_irqsave(&card
->ctl_files_rwlock
, flags
);
86 list_add_tail(&ctl
->list
, &card
->ctl_files
);
87 write_unlock_irqrestore(&card
->ctl_files_rwlock
, flags
);
91 module_put(card
->module
);
93 snd_card_file_remove(card
, file
);
98 static void snd_ctl_empty_read_queue(struct snd_ctl_file
* ctl
)
101 struct snd_kctl_event
*cread
;
103 spin_lock_irqsave(&ctl
->read_lock
, flags
);
104 while (!list_empty(&ctl
->events
)) {
105 cread
= snd_kctl_event(ctl
->events
.next
);
106 list_del(&cread
->list
);
109 spin_unlock_irqrestore(&ctl
->read_lock
, flags
);
112 static int snd_ctl_release(struct inode
*inode
, struct file
*file
)
115 struct snd_card
*card
;
116 struct snd_ctl_file
*ctl
;
117 struct snd_kcontrol
*control
;
120 ctl
= file
->private_data
;
121 file
->private_data
= NULL
;
123 write_lock_irqsave(&card
->ctl_files_rwlock
, flags
);
124 list_del(&ctl
->list
);
125 write_unlock_irqrestore(&card
->ctl_files_rwlock
, flags
);
126 down_write(&card
->controls_rwsem
);
127 list_for_each_entry(control
, &card
->controls
, list
)
128 for (idx
= 0; idx
< control
->count
; idx
++)
129 if (control
->vd
[idx
].owner
== ctl
)
130 control
->vd
[idx
].owner
= NULL
;
131 up_write(&card
->controls_rwsem
);
132 snd_ctl_empty_read_queue(ctl
);
135 module_put(card
->module
);
136 snd_card_file_remove(card
, file
);
140 void snd_ctl_notify(struct snd_card
*card
, unsigned int mask
,
141 struct snd_ctl_elem_id
*id
)
144 struct snd_ctl_file
*ctl
;
145 struct snd_kctl_event
*ev
;
147 if (snd_BUG_ON(!card
|| !id
))
149 read_lock(&card
->ctl_files_rwlock
);
150 #if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
151 card
->mixer_oss_change_count
++;
153 list_for_each_entry(ctl
, &card
->ctl_files
, list
) {
154 if (!ctl
->subscribed
)
156 spin_lock_irqsave(&ctl
->read_lock
, flags
);
157 list_for_each_entry(ev
, &ctl
->events
, list
) {
158 if (ev
->id
.numid
== id
->numid
) {
163 ev
= kzalloc(sizeof(*ev
), GFP_ATOMIC
);
167 list_add_tail(&ev
->list
, &ctl
->events
);
169 snd_printk(KERN_ERR
"No memory available to allocate event\n");
172 wake_up(&ctl
->change_sleep
);
173 spin_unlock_irqrestore(&ctl
->read_lock
, flags
);
174 kill_fasync(&ctl
->fasync
, SIGIO
, POLL_IN
);
176 read_unlock(&card
->ctl_files_rwlock
);
179 EXPORT_SYMBOL(snd_ctl_notify
);
182 * snd_ctl_new - create a control instance from the template
183 * @control: the control template
184 * @access: the default control access
186 * Allocates a new struct snd_kcontrol instance and copies the given template
187 * to the new instance. It does not copy volatile data (access).
189 * Returns the pointer of the new instance, or NULL on failure.
191 static struct snd_kcontrol
*snd_ctl_new(struct snd_kcontrol
*control
,
194 struct snd_kcontrol
*kctl
;
197 if (snd_BUG_ON(!control
|| !control
->count
))
200 if (control
->count
> MAX_CONTROL_COUNT
)
203 kctl
= kzalloc(sizeof(*kctl
) + sizeof(struct snd_kcontrol_volatile
) * control
->count
, GFP_KERNEL
);
205 snd_printk(KERN_ERR
"Cannot allocate control instance\n");
209 for (idx
= 0; idx
< kctl
->count
; idx
++)
210 kctl
->vd
[idx
].access
= access
;
215 * snd_ctl_new1 - create a control instance from the template
216 * @ncontrol: the initialization record
217 * @private_data: the private data to set
219 * Allocates a new struct snd_kcontrol instance and initialize from the given
220 * template. When the access field of ncontrol is 0, it's assumed as
221 * READWRITE access. When the count field is 0, it's assumes as one.
223 * Returns the pointer of the newly generated instance, or NULL on failure.
225 struct snd_kcontrol
*snd_ctl_new1(const struct snd_kcontrol_new
*ncontrol
,
228 struct snd_kcontrol kctl
;
231 if (snd_BUG_ON(!ncontrol
|| !ncontrol
->info
))
233 memset(&kctl
, 0, sizeof(kctl
));
234 kctl
.id
.iface
= ncontrol
->iface
;
235 kctl
.id
.device
= ncontrol
->device
;
236 kctl
.id
.subdevice
= ncontrol
->subdevice
;
237 if (ncontrol
->name
) {
238 strlcpy(kctl
.id
.name
, ncontrol
->name
, sizeof(kctl
.id
.name
));
239 if (strcmp(ncontrol
->name
, kctl
.id
.name
) != 0)
240 snd_printk(KERN_WARNING
241 "Control name '%s' truncated to '%s'\n",
242 ncontrol
->name
, kctl
.id
.name
);
244 kctl
.id
.index
= ncontrol
->index
;
245 kctl
.count
= ncontrol
->count
? ncontrol
->count
: 1;
246 access
= ncontrol
->access
== 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE
:
247 (ncontrol
->access
& (SNDRV_CTL_ELEM_ACCESS_READWRITE
|
248 SNDRV_CTL_ELEM_ACCESS_INACTIVE
|
249 SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE
|
250 SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND
|
251 SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK
));
252 kctl
.info
= ncontrol
->info
;
253 kctl
.get
= ncontrol
->get
;
254 kctl
.put
= ncontrol
->put
;
255 kctl
.tlv
.p
= ncontrol
->tlv
.p
;
256 kctl
.private_value
= ncontrol
->private_value
;
257 kctl
.private_data
= private_data
;
258 return snd_ctl_new(&kctl
, access
);
261 EXPORT_SYMBOL(snd_ctl_new1
);
264 * snd_ctl_free_one - release the control instance
265 * @kcontrol: the control instance
267 * Releases the control instance created via snd_ctl_new()
269 * Don't call this after the control was added to the card.
271 void snd_ctl_free_one(struct snd_kcontrol
*kcontrol
)
274 if (kcontrol
->private_free
)
275 kcontrol
->private_free(kcontrol
);
280 EXPORT_SYMBOL(snd_ctl_free_one
);
282 static bool snd_ctl_remove_numid_conflict(struct snd_card
*card
,
285 struct snd_kcontrol
*kctl
;
287 list_for_each_entry(kctl
, &card
->controls
, list
) {
288 if (kctl
->id
.numid
< card
->last_numid
+ 1 + count
&&
289 kctl
->id
.numid
+ kctl
->count
> card
->last_numid
+ 1) {
290 card
->last_numid
= kctl
->id
.numid
+ kctl
->count
- 1;
297 static int snd_ctl_find_hole(struct snd_card
*card
, unsigned int count
)
299 unsigned int iter
= 100000;
301 while (snd_ctl_remove_numid_conflict(card
, count
)) {
303 /* this situation is very unlikely */
304 snd_printk(KERN_ERR
"unable to allocate new control numid\n");
312 * snd_ctl_add - add the control instance to the card
313 * @card: the card instance
314 * @kcontrol: the control instance to add
316 * Adds the control instance created via snd_ctl_new() or
317 * snd_ctl_new1() to the given card. Assigns also an unique
318 * numid used for fast search.
320 * Returns zero if successful, or a negative error code on failure.
322 * It frees automatically the control which cannot be added.
324 int snd_ctl_add(struct snd_card
*card
, struct snd_kcontrol
*kcontrol
)
326 struct snd_ctl_elem_id id
;
332 if (snd_BUG_ON(!card
|| !kcontrol
->info
))
335 down_write(&card
->controls_rwsem
);
336 if (snd_ctl_find_id(card
, &id
)) {
337 up_write(&card
->controls_rwsem
);
338 snd_printd(KERN_ERR
"control %i:%i:%i:%s:%i is already present\n",
347 if (snd_ctl_find_hole(card
, kcontrol
->count
) < 0) {
348 up_write(&card
->controls_rwsem
);
352 list_add_tail(&kcontrol
->list
, &card
->controls
);
353 card
->controls_count
+= kcontrol
->count
;
354 kcontrol
->id
.numid
= card
->last_numid
+ 1;
355 card
->last_numid
+= kcontrol
->count
;
356 up_write(&card
->controls_rwsem
);
357 for (idx
= 0; idx
< kcontrol
->count
; idx
++, id
.index
++, id
.numid
++)
358 snd_ctl_notify(card
, SNDRV_CTL_EVENT_MASK_ADD
, &id
);
362 snd_ctl_free_one(kcontrol
);
366 EXPORT_SYMBOL(snd_ctl_add
);
369 * snd_ctl_remove - remove the control from the card and release it
370 * @card: the card instance
371 * @kcontrol: the control instance to remove
373 * Removes the control from the card and then releases the instance.
374 * You don't need to call snd_ctl_free_one(). You must be in
375 * the write lock - down_write(&card->controls_rwsem).
377 * Returns 0 if successful, or a negative error code on failure.
379 int snd_ctl_remove(struct snd_card
*card
, struct snd_kcontrol
*kcontrol
)
381 struct snd_ctl_elem_id id
;
384 if (snd_BUG_ON(!card
|| !kcontrol
))
386 list_del(&kcontrol
->list
);
387 card
->controls_count
-= kcontrol
->count
;
389 for (idx
= 0; idx
< kcontrol
->count
; idx
++, id
.index
++, id
.numid
++)
390 snd_ctl_notify(card
, SNDRV_CTL_EVENT_MASK_REMOVE
, &id
);
391 snd_ctl_free_one(kcontrol
);
395 EXPORT_SYMBOL(snd_ctl_remove
);
398 * snd_ctl_remove_id - remove the control of the given id and release it
399 * @card: the card instance
400 * @id: the control id to remove
402 * Finds the control instance with the given id, removes it from the
403 * card list and releases it.
405 * Returns 0 if successful, or a negative error code on failure.
407 int snd_ctl_remove_id(struct snd_card
*card
, struct snd_ctl_elem_id
*id
)
409 struct snd_kcontrol
*kctl
;
412 down_write(&card
->controls_rwsem
);
413 kctl
= snd_ctl_find_id(card
, id
);
415 up_write(&card
->controls_rwsem
);
418 ret
= snd_ctl_remove(card
, kctl
);
419 up_write(&card
->controls_rwsem
);
423 EXPORT_SYMBOL(snd_ctl_remove_id
);
426 * snd_ctl_remove_user_ctl - remove and release the unlocked user control
427 * @file: active control handle
428 * @id: the control id to remove
430 * Finds the control instance with the given id, removes it from the
431 * card list and releases it.
433 * Returns 0 if successful, or a negative error code on failure.
435 static int snd_ctl_remove_user_ctl(struct snd_ctl_file
* file
,
436 struct snd_ctl_elem_id
*id
)
438 struct snd_card
*card
= file
->card
;
439 struct snd_kcontrol
*kctl
;
442 down_write(&card
->controls_rwsem
);
443 kctl
= snd_ctl_find_id(card
, id
);
448 if (!(kctl
->vd
[0].access
& SNDRV_CTL_ELEM_ACCESS_USER
)) {
452 for (idx
= 0; idx
< kctl
->count
; idx
++)
453 if (kctl
->vd
[idx
].owner
!= NULL
&& kctl
->vd
[idx
].owner
!= file
) {
457 ret
= snd_ctl_remove(card
, kctl
);
460 card
->user_ctl_count
--;
462 up_write(&card
->controls_rwsem
);
467 * snd_ctl_activate_id - activate/inactivate the control of the given id
468 * @card: the card instance
469 * @id: the control id to activate/inactivate
470 * @active: non-zero to activate
472 * Finds the control instance with the given id, and activate or
473 * inactivate the control together with notification, if changed.
475 * Returns 0 if unchanged, 1 if changed, or a negative error code on failure.
477 int snd_ctl_activate_id(struct snd_card
*card
, struct snd_ctl_elem_id
*id
,
480 struct snd_kcontrol
*kctl
;
481 struct snd_kcontrol_volatile
*vd
;
482 unsigned int index_offset
;
485 down_write(&card
->controls_rwsem
);
486 kctl
= snd_ctl_find_id(card
, id
);
491 index_offset
= snd_ctl_get_ioff(kctl
, &kctl
->id
);
492 vd
= &kctl
->vd
[index_offset
];
495 if (!(vd
->access
& SNDRV_CTL_ELEM_ACCESS_INACTIVE
))
497 vd
->access
&= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE
;
499 if (vd
->access
& SNDRV_CTL_ELEM_ACCESS_INACTIVE
)
501 vd
->access
|= SNDRV_CTL_ELEM_ACCESS_INACTIVE
;
505 up_write(&card
->controls_rwsem
);
507 snd_ctl_notify(card
, SNDRV_CTL_EVENT_MASK_INFO
, id
);
510 EXPORT_SYMBOL_GPL(snd_ctl_activate_id
);
513 * snd_ctl_rename_id - replace the id of a control on the card
514 * @card: the card instance
515 * @src_id: the old id
516 * @dst_id: the new id
518 * Finds the control with the old id from the card, and replaces the
519 * id with the new one.
521 * Returns zero if successful, or a negative error code on failure.
523 int snd_ctl_rename_id(struct snd_card
*card
, struct snd_ctl_elem_id
*src_id
,
524 struct snd_ctl_elem_id
*dst_id
)
526 struct snd_kcontrol
*kctl
;
528 down_write(&card
->controls_rwsem
);
529 kctl
= snd_ctl_find_id(card
, src_id
);
531 up_write(&card
->controls_rwsem
);
535 kctl
->id
.numid
= card
->last_numid
+ 1;
536 card
->last_numid
+= kctl
->count
;
537 up_write(&card
->controls_rwsem
);
541 EXPORT_SYMBOL(snd_ctl_rename_id
);
544 * snd_ctl_find_numid - find the control instance with the given number-id
545 * @card: the card instance
546 * @numid: the number-id to search
548 * Finds the control instance with the given number-id from the card.
550 * Returns the pointer of the instance if found, or NULL if not.
552 * The caller must down card->controls_rwsem before calling this function
553 * (if the race condition can happen).
555 struct snd_kcontrol
*snd_ctl_find_numid(struct snd_card
*card
, unsigned int numid
)
557 struct snd_kcontrol
*kctl
;
559 if (snd_BUG_ON(!card
|| !numid
))
561 list_for_each_entry(kctl
, &card
->controls
, list
) {
562 if (kctl
->id
.numid
<= numid
&& kctl
->id
.numid
+ kctl
->count
> numid
)
568 EXPORT_SYMBOL(snd_ctl_find_numid
);
571 * snd_ctl_find_id - find the control instance with the given id
572 * @card: the card instance
573 * @id: the id to search
575 * Finds the control instance with the given id from the card.
577 * Returns the pointer of the instance if found, or NULL if not.
579 * The caller must down card->controls_rwsem before calling this function
580 * (if the race condition can happen).
582 struct snd_kcontrol
*snd_ctl_find_id(struct snd_card
*card
,
583 struct snd_ctl_elem_id
*id
)
585 struct snd_kcontrol
*kctl
;
587 if (snd_BUG_ON(!card
|| !id
))
590 return snd_ctl_find_numid(card
, id
->numid
);
591 list_for_each_entry(kctl
, &card
->controls
, list
) {
592 if (kctl
->id
.iface
!= id
->iface
)
594 if (kctl
->id
.device
!= id
->device
)
596 if (kctl
->id
.subdevice
!= id
->subdevice
)
598 if (strncmp(kctl
->id
.name
, id
->name
, sizeof(kctl
->id
.name
)))
600 if (kctl
->id
.index
> id
->index
)
602 if (kctl
->id
.index
+ kctl
->count
<= id
->index
)
609 EXPORT_SYMBOL(snd_ctl_find_id
);
611 static int snd_ctl_card_info(struct snd_card
*card
, struct snd_ctl_file
* ctl
,
612 unsigned int cmd
, void __user
*arg
)
614 struct snd_ctl_card_info
*info
;
616 info
= kzalloc(sizeof(*info
), GFP_KERNEL
);
619 down_read(&snd_ioctl_rwsem
);
620 info
->card
= card
->number
;
621 strlcpy(info
->id
, card
->id
, sizeof(info
->id
));
622 strlcpy(info
->driver
, card
->driver
, sizeof(info
->driver
));
623 strlcpy(info
->name
, card
->shortname
, sizeof(info
->name
));
624 strlcpy(info
->longname
, card
->longname
, sizeof(info
->longname
));
625 strlcpy(info
->mixername
, card
->mixername
, sizeof(info
->mixername
));
626 strlcpy(info
->components
, card
->components
, sizeof(info
->components
));
627 up_read(&snd_ioctl_rwsem
);
628 if (copy_to_user(arg
, info
, sizeof(struct snd_ctl_card_info
))) {
636 static int snd_ctl_elem_list(struct snd_card
*card
,
637 struct snd_ctl_elem_list __user
*_list
)
639 struct list_head
*plist
;
640 struct snd_ctl_elem_list list
;
641 struct snd_kcontrol
*kctl
;
642 struct snd_ctl_elem_id
*dst
, *id
;
643 unsigned int offset
, space
, first
, jidx
;
645 if (copy_from_user(&list
, _list
, sizeof(list
)))
647 offset
= list
.offset
;
650 /* try limit maximum space */
654 /* allocate temporary buffer for atomic operation */
655 dst
= vmalloc(space
* sizeof(struct snd_ctl_elem_id
));
658 down_read(&card
->controls_rwsem
);
659 list
.count
= card
->controls_count
;
660 plist
= card
->controls
.next
;
661 while (plist
!= &card
->controls
) {
664 kctl
= snd_kcontrol(plist
);
665 if (offset
< kctl
->count
)
667 offset
-= kctl
->count
;
672 while (space
> 0 && plist
!= &card
->controls
) {
673 kctl
= snd_kcontrol(plist
);
674 for (jidx
= offset
; space
> 0 && jidx
< kctl
->count
; jidx
++) {
675 snd_ctl_build_ioff(id
, kctl
, jidx
);
683 up_read(&card
->controls_rwsem
);
685 copy_to_user(list
.pids
, dst
,
686 list
.used
* sizeof(struct snd_ctl_elem_id
))) {
692 down_read(&card
->controls_rwsem
);
693 list
.count
= card
->controls_count
;
694 up_read(&card
->controls_rwsem
);
696 if (copy_to_user(_list
, &list
, sizeof(list
)))
701 static int snd_ctl_elem_info(struct snd_ctl_file
*ctl
,
702 struct snd_ctl_elem_info
*info
)
704 struct snd_card
*card
= ctl
->card
;
705 struct snd_kcontrol
*kctl
;
706 struct snd_kcontrol_volatile
*vd
;
707 unsigned int index_offset
;
710 down_read(&card
->controls_rwsem
);
711 kctl
= snd_ctl_find_id(card
, &info
->id
);
713 up_read(&card
->controls_rwsem
);
716 #ifdef CONFIG_SND_DEBUG
719 result
= kctl
->info(kctl
, info
);
721 snd_BUG_ON(info
->access
);
722 index_offset
= snd_ctl_get_ioff(kctl
, &info
->id
);
723 vd
= &kctl
->vd
[index_offset
];
724 snd_ctl_build_ioff(&info
->id
, kctl
, index_offset
);
725 info
->access
= vd
->access
;
727 info
->access
|= SNDRV_CTL_ELEM_ACCESS_LOCK
;
728 if (vd
->owner
== ctl
)
729 info
->access
|= SNDRV_CTL_ELEM_ACCESS_OWNER
;
730 info
->owner
= pid_vnr(vd
->owner
->pid
);
735 up_read(&card
->controls_rwsem
);
739 static int snd_ctl_elem_info_user(struct snd_ctl_file
*ctl
,
740 struct snd_ctl_elem_info __user
*_info
)
742 struct snd_ctl_elem_info info
;
745 if (copy_from_user(&info
, _info
, sizeof(info
)))
747 snd_power_lock(ctl
->card
);
748 result
= snd_power_wait(ctl
->card
, SNDRV_CTL_POWER_D0
);
750 result
= snd_ctl_elem_info(ctl
, &info
);
751 snd_power_unlock(ctl
->card
);
753 if (copy_to_user(_info
, &info
, sizeof(info
)))
758 static int snd_ctl_elem_read(struct snd_card
*card
,
759 struct snd_ctl_elem_value
*control
)
761 struct snd_kcontrol
*kctl
;
762 struct snd_kcontrol_volatile
*vd
;
763 unsigned int index_offset
;
766 down_read(&card
->controls_rwsem
);
767 kctl
= snd_ctl_find_id(card
, &control
->id
);
771 index_offset
= snd_ctl_get_ioff(kctl
, &control
->id
);
772 vd
= &kctl
->vd
[index_offset
];
773 if ((vd
->access
& SNDRV_CTL_ELEM_ACCESS_READ
) &&
775 snd_ctl_build_ioff(&control
->id
, kctl
, index_offset
);
776 result
= kctl
->get(kctl
, control
);
780 up_read(&card
->controls_rwsem
);
784 static int snd_ctl_elem_read_user(struct snd_card
*card
,
785 struct snd_ctl_elem_value __user
*_control
)
787 struct snd_ctl_elem_value
*control
;
790 control
= memdup_user(_control
, sizeof(*control
));
792 return PTR_ERR(control
);
794 snd_power_lock(card
);
795 result
= snd_power_wait(card
, SNDRV_CTL_POWER_D0
);
797 result
= snd_ctl_elem_read(card
, control
);
798 snd_power_unlock(card
);
800 if (copy_to_user(_control
, control
, sizeof(*control
)))
806 static int snd_ctl_elem_write(struct snd_card
*card
, struct snd_ctl_file
*file
,
807 struct snd_ctl_elem_value
*control
)
809 struct snd_kcontrol
*kctl
;
810 struct snd_kcontrol_volatile
*vd
;
811 unsigned int index_offset
;
814 down_read(&card
->controls_rwsem
);
815 kctl
= snd_ctl_find_id(card
, &control
->id
);
819 index_offset
= snd_ctl_get_ioff(kctl
, &control
->id
);
820 vd
= &kctl
->vd
[index_offset
];
821 if (!(vd
->access
& SNDRV_CTL_ELEM_ACCESS_WRITE
) ||
823 (file
&& vd
->owner
&& vd
->owner
!= file
)) {
826 snd_ctl_build_ioff(&control
->id
, kctl
, index_offset
);
827 result
= kctl
->put(kctl
, control
);
830 up_read(&card
->controls_rwsem
);
831 snd_ctl_notify(card
, SNDRV_CTL_EVENT_MASK_VALUE
,
836 up_read(&card
->controls_rwsem
);
840 static int snd_ctl_elem_write_user(struct snd_ctl_file
*file
,
841 struct snd_ctl_elem_value __user
*_control
)
843 struct snd_ctl_elem_value
*control
;
844 struct snd_card
*card
;
847 control
= memdup_user(_control
, sizeof(*control
));
849 return PTR_ERR(control
);
852 snd_power_lock(card
);
853 result
= snd_power_wait(card
, SNDRV_CTL_POWER_D0
);
855 result
= snd_ctl_elem_write(card
, file
, control
);
856 snd_power_unlock(card
);
858 if (copy_to_user(_control
, control
, sizeof(*control
)))
864 static int snd_ctl_elem_lock(struct snd_ctl_file
*file
,
865 struct snd_ctl_elem_id __user
*_id
)
867 struct snd_card
*card
= file
->card
;
868 struct snd_ctl_elem_id id
;
869 struct snd_kcontrol
*kctl
;
870 struct snd_kcontrol_volatile
*vd
;
873 if (copy_from_user(&id
, _id
, sizeof(id
)))
875 down_write(&card
->controls_rwsem
);
876 kctl
= snd_ctl_find_id(card
, &id
);
880 vd
= &kctl
->vd
[snd_ctl_get_ioff(kctl
, &id
)];
881 if (vd
->owner
!= NULL
)
888 up_write(&card
->controls_rwsem
);
892 static int snd_ctl_elem_unlock(struct snd_ctl_file
*file
,
893 struct snd_ctl_elem_id __user
*_id
)
895 struct snd_card
*card
= file
->card
;
896 struct snd_ctl_elem_id id
;
897 struct snd_kcontrol
*kctl
;
898 struct snd_kcontrol_volatile
*vd
;
901 if (copy_from_user(&id
, _id
, sizeof(id
)))
903 down_write(&card
->controls_rwsem
);
904 kctl
= snd_ctl_find_id(card
, &id
);
908 vd
= &kctl
->vd
[snd_ctl_get_ioff(kctl
, &id
)];
909 if (vd
->owner
== NULL
)
911 else if (vd
->owner
!= file
)
918 up_write(&card
->controls_rwsem
);
922 struct user_element
{
923 struct snd_ctl_elem_info info
;
924 void *elem_data
; /* element data */
925 unsigned long elem_data_size
; /* size of element data in bytes */
926 void *tlv_data
; /* TLV data */
927 unsigned long tlv_data_size
; /* TLV data size */
928 void *priv_data
; /* private data (like strings for enumerated type) */
929 unsigned long priv_data_size
; /* size of private data in bytes */
932 static int snd_ctl_elem_user_info(struct snd_kcontrol
*kcontrol
,
933 struct snd_ctl_elem_info
*uinfo
)
935 struct user_element
*ue
= kcontrol
->private_data
;
941 static int snd_ctl_elem_user_get(struct snd_kcontrol
*kcontrol
,
942 struct snd_ctl_elem_value
*ucontrol
)
944 struct user_element
*ue
= kcontrol
->private_data
;
946 memcpy(&ucontrol
->value
, ue
->elem_data
, ue
->elem_data_size
);
950 static int snd_ctl_elem_user_put(struct snd_kcontrol
*kcontrol
,
951 struct snd_ctl_elem_value
*ucontrol
)
954 struct user_element
*ue
= kcontrol
->private_data
;
956 change
= memcmp(&ucontrol
->value
, ue
->elem_data
, ue
->elem_data_size
) != 0;
958 memcpy(ue
->elem_data
, &ucontrol
->value
, ue
->elem_data_size
);
962 static int snd_ctl_elem_user_tlv(struct snd_kcontrol
*kcontrol
,
965 unsigned int __user
*tlv
)
967 struct user_element
*ue
= kcontrol
->private_data
;
972 if (size
> 1024 * 128) /* sane value */
975 new_data
= memdup_user(tlv
, size
);
976 if (IS_ERR(new_data
))
977 return PTR_ERR(new_data
);
978 change
= ue
->tlv_data_size
!= size
;
980 change
= memcmp(ue
->tlv_data
, new_data
, size
);
982 ue
->tlv_data
= new_data
;
983 ue
->tlv_data_size
= size
;
985 if (! ue
->tlv_data_size
|| ! ue
->tlv_data
)
987 if (size
< ue
->tlv_data_size
)
989 if (copy_to_user(tlv
, ue
->tlv_data
, ue
->tlv_data_size
))
995 static void snd_ctl_elem_user_free(struct snd_kcontrol
*kcontrol
)
997 struct user_element
*ue
= kcontrol
->private_data
;
1003 static int snd_ctl_elem_add(struct snd_ctl_file
*file
,
1004 struct snd_ctl_elem_info
*info
, int replace
)
1006 struct snd_card
*card
= file
->card
;
1007 struct snd_kcontrol kctl
, *_kctl
;
1008 unsigned int access
;
1010 struct user_element
*ue
;
1013 if (card
->user_ctl_count
>= MAX_USER_CONTROLS
)
1015 if (info
->count
< 1)
1017 access
= info
->access
== 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE
:
1018 (info
->access
& (SNDRV_CTL_ELEM_ACCESS_READWRITE
|
1019 SNDRV_CTL_ELEM_ACCESS_INACTIVE
|
1020 SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE
));
1022 memset(&kctl
, 0, sizeof(kctl
));
1023 down_write(&card
->controls_rwsem
);
1024 _kctl
= snd_ctl_find_id(card
, &info
->id
);
1028 err
= snd_ctl_remove(card
, _kctl
);
1035 up_write(&card
->controls_rwsem
);
1038 memcpy(&kctl
.id
, &info
->id
, sizeof(info
->id
));
1039 kctl
.count
= info
->owner
? info
->owner
: 1;
1040 access
|= SNDRV_CTL_ELEM_ACCESS_USER
;
1041 kctl
.info
= snd_ctl_elem_user_info
;
1042 if (access
& SNDRV_CTL_ELEM_ACCESS_READ
)
1043 kctl
.get
= snd_ctl_elem_user_get
;
1044 if (access
& SNDRV_CTL_ELEM_ACCESS_WRITE
)
1045 kctl
.put
= snd_ctl_elem_user_put
;
1046 if (access
& SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE
) {
1047 kctl
.tlv
.c
= snd_ctl_elem_user_tlv
;
1048 access
|= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK
;
1050 switch (info
->type
) {
1051 case SNDRV_CTL_ELEM_TYPE_BOOLEAN
:
1052 case SNDRV_CTL_ELEM_TYPE_INTEGER
:
1053 private_size
= sizeof(long);
1054 if (info
->count
> 128)
1057 case SNDRV_CTL_ELEM_TYPE_INTEGER64
:
1058 private_size
= sizeof(long long);
1059 if (info
->count
> 64)
1062 case SNDRV_CTL_ELEM_TYPE_BYTES
:
1063 private_size
= sizeof(unsigned char);
1064 if (info
->count
> 512)
1067 case SNDRV_CTL_ELEM_TYPE_IEC958
:
1068 private_size
= sizeof(struct snd_aes_iec958
);
1069 if (info
->count
!= 1)
1075 private_size
*= info
->count
;
1076 ue
= kzalloc(sizeof(struct user_element
) + private_size
, GFP_KERNEL
);
1080 ue
->info
.access
= 0;
1081 ue
->elem_data
= (char *)ue
+ sizeof(*ue
);
1082 ue
->elem_data_size
= private_size
;
1083 kctl
.private_free
= snd_ctl_elem_user_free
;
1084 _kctl
= snd_ctl_new(&kctl
, access
);
1085 if (_kctl
== NULL
) {
1089 _kctl
->private_data
= ue
;
1090 for (idx
= 0; idx
< _kctl
->count
; idx
++)
1091 _kctl
->vd
[idx
].owner
= file
;
1092 err
= snd_ctl_add(card
, _kctl
);
1096 down_write(&card
->controls_rwsem
);
1097 card
->user_ctl_count
++;
1098 up_write(&card
->controls_rwsem
);
1103 static int snd_ctl_elem_add_user(struct snd_ctl_file
*file
,
1104 struct snd_ctl_elem_info __user
*_info
, int replace
)
1106 struct snd_ctl_elem_info info
;
1107 if (copy_from_user(&info
, _info
, sizeof(info
)))
1109 return snd_ctl_elem_add(file
, &info
, replace
);
1112 static int snd_ctl_elem_remove(struct snd_ctl_file
*file
,
1113 struct snd_ctl_elem_id __user
*_id
)
1115 struct snd_ctl_elem_id id
;
1117 if (copy_from_user(&id
, _id
, sizeof(id
)))
1119 return snd_ctl_remove_user_ctl(file
, &id
);
1122 static int snd_ctl_subscribe_events(struct snd_ctl_file
*file
, int __user
*ptr
)
1125 if (get_user(subscribe
, ptr
))
1127 if (subscribe
< 0) {
1128 subscribe
= file
->subscribed
;
1129 if (put_user(subscribe
, ptr
))
1134 file
->subscribed
= 1;
1136 } else if (file
->subscribed
) {
1137 snd_ctl_empty_read_queue(file
);
1138 file
->subscribed
= 0;
1143 static int snd_ctl_tlv_ioctl(struct snd_ctl_file
*file
,
1144 struct snd_ctl_tlv __user
*_tlv
,
1147 struct snd_card
*card
= file
->card
;
1148 struct snd_ctl_tlv tlv
;
1149 struct snd_kcontrol
*kctl
;
1150 struct snd_kcontrol_volatile
*vd
;
1154 if (copy_from_user(&tlv
, _tlv
, sizeof(tlv
)))
1156 if (tlv
.length
< sizeof(unsigned int) * 2)
1158 down_read(&card
->controls_rwsem
);
1159 kctl
= snd_ctl_find_numid(card
, tlv
.numid
);
1164 if (kctl
->tlv
.p
== NULL
) {
1168 vd
= &kctl
->vd
[tlv
.numid
- kctl
->id
.numid
];
1169 if ((op_flag
== 0 && (vd
->access
& SNDRV_CTL_ELEM_ACCESS_TLV_READ
) == 0) ||
1170 (op_flag
> 0 && (vd
->access
& SNDRV_CTL_ELEM_ACCESS_TLV_WRITE
) == 0) ||
1171 (op_flag
< 0 && (vd
->access
& SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND
) == 0)) {
1175 if (vd
->access
& SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK
) {
1176 if (vd
->owner
!= NULL
&& vd
->owner
!= file
) {
1180 err
= kctl
->tlv
.c(kctl
, op_flag
, tlv
.length
, _tlv
->tlv
);
1182 up_read(&card
->controls_rwsem
);
1183 snd_ctl_notify(card
, SNDRV_CTL_EVENT_MASK_TLV
, &kctl
->id
);
1191 len
= kctl
->tlv
.p
[1] + 2 * sizeof(unsigned int);
1192 if (tlv
.length
< len
) {
1196 if (copy_to_user(_tlv
->tlv
, kctl
->tlv
.p
, len
))
1200 up_read(&card
->controls_rwsem
);
1204 static long snd_ctl_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
1206 struct snd_ctl_file
*ctl
;
1207 struct snd_card
*card
;
1208 struct snd_kctl_ioctl
*p
;
1209 void __user
*argp
= (void __user
*)arg
;
1210 int __user
*ip
= argp
;
1213 ctl
= file
->private_data
;
1215 if (snd_BUG_ON(!card
))
1218 case SNDRV_CTL_IOCTL_PVERSION
:
1219 return put_user(SNDRV_CTL_VERSION
, ip
) ? -EFAULT
: 0;
1220 case SNDRV_CTL_IOCTL_CARD_INFO
:
1221 return snd_ctl_card_info(card
, ctl
, cmd
, argp
);
1222 case SNDRV_CTL_IOCTL_ELEM_LIST
:
1223 return snd_ctl_elem_list(card
, argp
);
1224 case SNDRV_CTL_IOCTL_ELEM_INFO
:
1225 return snd_ctl_elem_info_user(ctl
, argp
);
1226 case SNDRV_CTL_IOCTL_ELEM_READ
:
1227 return snd_ctl_elem_read_user(card
, argp
);
1228 case SNDRV_CTL_IOCTL_ELEM_WRITE
:
1229 return snd_ctl_elem_write_user(ctl
, argp
);
1230 case SNDRV_CTL_IOCTL_ELEM_LOCK
:
1231 return snd_ctl_elem_lock(ctl
, argp
);
1232 case SNDRV_CTL_IOCTL_ELEM_UNLOCK
:
1233 return snd_ctl_elem_unlock(ctl
, argp
);
1234 case SNDRV_CTL_IOCTL_ELEM_ADD
:
1235 return snd_ctl_elem_add_user(ctl
, argp
, 0);
1236 case SNDRV_CTL_IOCTL_ELEM_REPLACE
:
1237 return snd_ctl_elem_add_user(ctl
, argp
, 1);
1238 case SNDRV_CTL_IOCTL_ELEM_REMOVE
:
1239 return snd_ctl_elem_remove(ctl
, argp
);
1240 case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS
:
1241 return snd_ctl_subscribe_events(ctl
, ip
);
1242 case SNDRV_CTL_IOCTL_TLV_READ
:
1243 return snd_ctl_tlv_ioctl(ctl
, argp
, 0);
1244 case SNDRV_CTL_IOCTL_TLV_WRITE
:
1245 return snd_ctl_tlv_ioctl(ctl
, argp
, 1);
1246 case SNDRV_CTL_IOCTL_TLV_COMMAND
:
1247 return snd_ctl_tlv_ioctl(ctl
, argp
, -1);
1248 case SNDRV_CTL_IOCTL_POWER
:
1249 return -ENOPROTOOPT
;
1250 case SNDRV_CTL_IOCTL_POWER_STATE
:
1252 return put_user(card
->power_state
, ip
) ? -EFAULT
: 0;
1254 return put_user(SNDRV_CTL_POWER_D0
, ip
) ? -EFAULT
: 0;
1257 down_read(&snd_ioctl_rwsem
);
1258 list_for_each_entry(p
, &snd_control_ioctls
, list
) {
1259 err
= p
->fioctl(card
, ctl
, cmd
, arg
);
1260 if (err
!= -ENOIOCTLCMD
) {
1261 up_read(&snd_ioctl_rwsem
);
1265 up_read(&snd_ioctl_rwsem
);
1266 snd_printdd("unknown ioctl = 0x%x\n", cmd
);
1270 static ssize_t
snd_ctl_read(struct file
*file
, char __user
*buffer
,
1271 size_t count
, loff_t
* offset
)
1273 struct snd_ctl_file
*ctl
;
1277 ctl
= file
->private_data
;
1278 if (snd_BUG_ON(!ctl
|| !ctl
->card
))
1280 if (!ctl
->subscribed
)
1282 if (count
< sizeof(struct snd_ctl_event
))
1284 spin_lock_irq(&ctl
->read_lock
);
1285 while (count
>= sizeof(struct snd_ctl_event
)) {
1286 struct snd_ctl_event ev
;
1287 struct snd_kctl_event
*kev
;
1288 while (list_empty(&ctl
->events
)) {
1290 if ((file
->f_flags
& O_NONBLOCK
) != 0 || result
> 0) {
1294 init_waitqueue_entry(&wait
, current
);
1295 add_wait_queue(&ctl
->change_sleep
, &wait
);
1296 set_current_state(TASK_INTERRUPTIBLE
);
1297 spin_unlock_irq(&ctl
->read_lock
);
1299 remove_wait_queue(&ctl
->change_sleep
, &wait
);
1300 if (signal_pending(current
))
1301 return -ERESTARTSYS
;
1302 spin_lock_irq(&ctl
->read_lock
);
1304 kev
= snd_kctl_event(ctl
->events
.next
);
1305 ev
.type
= SNDRV_CTL_EVENT_ELEM
;
1306 ev
.data
.elem
.mask
= kev
->mask
;
1307 ev
.data
.elem
.id
= kev
->id
;
1308 list_del(&kev
->list
);
1309 spin_unlock_irq(&ctl
->read_lock
);
1311 if (copy_to_user(buffer
, &ev
, sizeof(struct snd_ctl_event
))) {
1315 spin_lock_irq(&ctl
->read_lock
);
1316 buffer
+= sizeof(struct snd_ctl_event
);
1317 count
-= sizeof(struct snd_ctl_event
);
1318 result
+= sizeof(struct snd_ctl_event
);
1321 spin_unlock_irq(&ctl
->read_lock
);
1323 return result
> 0 ? result
: err
;
1326 static unsigned int snd_ctl_poll(struct file
*file
, poll_table
* wait
)
1329 struct snd_ctl_file
*ctl
;
1331 ctl
= file
->private_data
;
1332 if (!ctl
->subscribed
)
1334 poll_wait(file
, &ctl
->change_sleep
, wait
);
1337 if (!list_empty(&ctl
->events
))
1338 mask
|= POLLIN
| POLLRDNORM
;
1344 * register the device-specific control-ioctls.
1345 * called from each device manager like pcm.c, hwdep.c, etc.
1347 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn
, struct list_head
*lists
)
1349 struct snd_kctl_ioctl
*pn
;
1351 pn
= kzalloc(sizeof(struct snd_kctl_ioctl
), GFP_KERNEL
);
1355 down_write(&snd_ioctl_rwsem
);
1356 list_add_tail(&pn
->list
, lists
);
1357 up_write(&snd_ioctl_rwsem
);
1361 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn
)
1363 return _snd_ctl_register_ioctl(fcn
, &snd_control_ioctls
);
1366 EXPORT_SYMBOL(snd_ctl_register_ioctl
);
1368 #ifdef CONFIG_COMPAT
1369 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn
)
1371 return _snd_ctl_register_ioctl(fcn
, &snd_control_compat_ioctls
);
1374 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat
);
1378 * de-register the device-specific control-ioctls.
1380 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn
,
1381 struct list_head
*lists
)
1383 struct snd_kctl_ioctl
*p
;
1385 if (snd_BUG_ON(!fcn
))
1387 down_write(&snd_ioctl_rwsem
);
1388 list_for_each_entry(p
, lists
, list
) {
1389 if (p
->fioctl
== fcn
) {
1391 up_write(&snd_ioctl_rwsem
);
1396 up_write(&snd_ioctl_rwsem
);
1401 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn
)
1403 return _snd_ctl_unregister_ioctl(fcn
, &snd_control_ioctls
);
1406 EXPORT_SYMBOL(snd_ctl_unregister_ioctl
);
1408 #ifdef CONFIG_COMPAT
1409 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn
)
1411 return _snd_ctl_unregister_ioctl(fcn
, &snd_control_compat_ioctls
);
1414 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat
);
1417 static int snd_ctl_fasync(int fd
, struct file
* file
, int on
)
1419 struct snd_ctl_file
*ctl
;
1421 ctl
= file
->private_data
;
1422 return fasync_helper(fd
, file
, on
, &ctl
->fasync
);
1428 #ifdef CONFIG_COMPAT
1429 #include "control_compat.c"
1431 #define snd_ctl_ioctl_compat NULL
1438 static const struct file_operations snd_ctl_f_ops
=
1440 .owner
= THIS_MODULE
,
1441 .read
= snd_ctl_read
,
1442 .open
= snd_ctl_open
,
1443 .release
= snd_ctl_release
,
1444 .llseek
= no_llseek
,
1445 .poll
= snd_ctl_poll
,
1446 .unlocked_ioctl
= snd_ctl_ioctl
,
1447 .compat_ioctl
= snd_ctl_ioctl_compat
,
1448 .fasync
= snd_ctl_fasync
,
1452 * registration of the control device
1454 static int snd_ctl_dev_register(struct snd_device
*device
)
1456 struct snd_card
*card
= device
->device_data
;
1460 if (snd_BUG_ON(!card
))
1462 cardnum
= card
->number
;
1463 if (snd_BUG_ON(cardnum
< 0 || cardnum
>= SNDRV_CARDS
))
1465 sprintf(name
, "controlC%i", cardnum
);
1466 if ((err
= snd_register_device(SNDRV_DEVICE_TYPE_CONTROL
, card
, -1,
1467 &snd_ctl_f_ops
, card
, name
)) < 0)
1473 * disconnection of the control device
1475 static int snd_ctl_dev_disconnect(struct snd_device
*device
)
1477 struct snd_card
*card
= device
->device_data
;
1478 struct snd_ctl_file
*ctl
;
1481 if (snd_BUG_ON(!card
))
1483 cardnum
= card
->number
;
1484 if (snd_BUG_ON(cardnum
< 0 || cardnum
>= SNDRV_CARDS
))
1487 read_lock(&card
->ctl_files_rwlock
);
1488 list_for_each_entry(ctl
, &card
->ctl_files
, list
) {
1489 wake_up(&ctl
->change_sleep
);
1490 kill_fasync(&ctl
->fasync
, SIGIO
, POLL_ERR
);
1492 read_unlock(&card
->ctl_files_rwlock
);
1494 if ((err
= snd_unregister_device(SNDRV_DEVICE_TYPE_CONTROL
,
1503 static int snd_ctl_dev_free(struct snd_device
*device
)
1505 struct snd_card
*card
= device
->device_data
;
1506 struct snd_kcontrol
*control
;
1508 down_write(&card
->controls_rwsem
);
1509 while (!list_empty(&card
->controls
)) {
1510 control
= snd_kcontrol(card
->controls
.next
);
1511 snd_ctl_remove(card
, control
);
1513 up_write(&card
->controls_rwsem
);
1518 * create control core:
1519 * called from init.c
1521 int snd_ctl_create(struct snd_card
*card
)
1523 static struct snd_device_ops ops
= {
1524 .dev_free
= snd_ctl_dev_free
,
1525 .dev_register
= snd_ctl_dev_register
,
1526 .dev_disconnect
= snd_ctl_dev_disconnect
,
1529 if (snd_BUG_ON(!card
))
1531 return snd_device_new(card
, SNDRV_DEV_CONTROL
, card
, &ops
);
1535 * Frequently used control callbacks/helpers
1537 int snd_ctl_boolean_mono_info(struct snd_kcontrol
*kcontrol
,
1538 struct snd_ctl_elem_info
*uinfo
)
1540 uinfo
->type
= SNDRV_CTL_ELEM_TYPE_BOOLEAN
;
1542 uinfo
->value
.integer
.min
= 0;
1543 uinfo
->value
.integer
.max
= 1;
1547 EXPORT_SYMBOL(snd_ctl_boolean_mono_info
);
1549 int snd_ctl_boolean_stereo_info(struct snd_kcontrol
*kcontrol
,
1550 struct snd_ctl_elem_info
*uinfo
)
1552 uinfo
->type
= SNDRV_CTL_ELEM_TYPE_BOOLEAN
;
1554 uinfo
->value
.integer
.min
= 0;
1555 uinfo
->value
.integer
.max
= 1;
1559 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info
);
1562 * snd_ctl_enum_info - fills the info structure for an enumerated control
1563 * @info: the structure to be filled
1564 * @channels: the number of the control's channels; often one
1565 * @items: the number of control values; also the size of @names
1566 * @names: an array containing the names of all control values
1568 * Sets all required fields in @info to their appropriate values.
1569 * If the control's accessibility is not the default (readable and writable),
1570 * the caller has to fill @info->access.
1572 int snd_ctl_enum_info(struct snd_ctl_elem_info
*info
, unsigned int channels
,
1573 unsigned int items
, const char *const names
[])
1575 info
->type
= SNDRV_CTL_ELEM_TYPE_ENUMERATED
;
1576 info
->count
= channels
;
1577 info
->value
.enumerated
.items
= items
;
1578 if (info
->value
.enumerated
.item
>= items
)
1579 info
->value
.enumerated
.item
= items
- 1;
1580 strlcpy(info
->value
.enumerated
.name
,
1581 names
[info
->value
.enumerated
.item
],
1582 sizeof(info
->value
.enumerated
.name
));
1585 EXPORT_SYMBOL(snd_ctl_enum_info
);