Commit 3cbdd753 authored by Takashi Iwai's avatar Takashi Iwai Committed by Mark Brown
Browse files

ALSA: Add snd_ctl_activate_id() 



Added a new API function snd_ctl_activate_id() for activate / inactivate
the control element dynamically.

Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
parent 80e1b84f

include/sound/control.h

+2 −0
Original line number Diff line number Diff line
@@ -115,6 +115,8 @@ int snd_ctl_add(struct snd_card * card, struct snd_kcontrol * kcontrol); 
int snd_ctl_remove(struct snd_card * card, struct snd_kcontrol * kcontrol);

int snd_ctl_remove_id(struct snd_card * card, struct snd_ctl_elem_id *id);

int snd_ctl_rename_id(struct snd_card * card, struct snd_ctl_elem_id *src_id, struct snd_ctl_elem_id *dst_id);

int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,

			int active);

struct snd_kcontrol *snd_ctl_find_numid(struct snd_card * card, unsigned int numid);

struct snd_kcontrol *snd_ctl_find_id(struct snd_card * card, struct snd_ctl_elem_id *id);

sound/core/control.c

+46 −0
Original line number Diff line number Diff line
@@ -465,6 +465,52 @@ static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file, 
	return ret;

}



/**

 * snd_ctl_activate_id - activate/inactivate the control of the given id

 * @card: the card instance

 * @id: the control id to activate/inactivate

 * @active: non-zero to activate

 *

 * Finds the control instance with the given id, and activate or

 * inactivate the control together with notification, if changed.

 *

 * Returns 0 if unchanged, 1 if changed, or a negative error code on failure.

 */

int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,

			int active)

{

	struct snd_kcontrol *kctl;

	struct snd_kcontrol_volatile *vd;

	unsigned int index_offset;

	int ret;



	down_write(&card->controls_rwsem);

	kctl = snd_ctl_find_id(card, id);

	if (kctl == NULL) {

		ret = -ENOENT;

		goto unlock;

	}

	index_offset = snd_ctl_get_ioff(kctl, &kctl->id);

	vd = &kctl->vd[index_offset];

	ret = 0;

	if (active) {

		if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))

			goto unlock;

		vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;

	} else {

		if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)

			goto unlock;

		vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;

	}

	ret = 1;

 unlock:

	up_write(&card->controls_rwsem);

	if (ret > 0)

		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, id);

	return ret;

}

EXPORT_SYMBOL_GPL(snd_ctl_activate_id);



/**

 * snd_ctl_rename_id - replace the id of a control on the card

 * @card: the card instance