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: Takashi Iwai <tiwai@suse.de> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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@ -115,6 +115,8 @@ int snd_ctl_add(struct snd_card * card, struct snd_kcontrol * kcontrol);
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int snd_ctl_remove(struct snd_card * card, struct snd_kcontrol * kcontrol);
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int snd_ctl_remove_id(struct snd_card * card, struct snd_ctl_elem_id *id);
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int snd_ctl_rename_id(struct snd_card * card, struct snd_ctl_elem_id *src_id, struct snd_ctl_elem_id *dst_id);
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int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
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int active);
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struct snd_kcontrol *snd_ctl_find_numid(struct snd_card * card, unsigned int numid);
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struct snd_kcontrol *snd_ctl_find_id(struct snd_card * card, struct snd_ctl_elem_id *id);
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@ -465,6 +465,52 @@ error:
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return ret;
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}
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/**
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* snd_ctl_activate_id - activate/inactivate the control of the given id
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* @card: the card instance
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* @id: the control id to activate/inactivate
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* @active: non-zero to activate
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*
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* Finds the control instance with the given id, and activate or
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* inactivate the control together with notification, if changed.
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*
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* Returns 0 if unchanged, 1 if changed, or a negative error code on failure.
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*/
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int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
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int active)
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{
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struct snd_kcontrol *kctl;
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struct snd_kcontrol_volatile *vd;
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unsigned int index_offset;
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int ret;
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down_write(&card->controls_rwsem);
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kctl = snd_ctl_find_id(card, id);
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if (kctl == NULL) {
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ret = -ENOENT;
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goto unlock;
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}
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index_offset = snd_ctl_get_ioff(kctl, &kctl->id);
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vd = &kctl->vd[index_offset];
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ret = 0;
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if (active) {
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if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
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goto unlock;
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vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
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} else {
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if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
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goto unlock;
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vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
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}
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ret = 1;
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unlock:
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up_write(&card->controls_rwsem);
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if (ret > 0)
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snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, id);
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return ret;
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}
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EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
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/**
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* snd_ctl_rename_id - replace the id of a control on the card
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* @card: the card instance
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