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![Takashi Iwai](/assets/img/avatar_default.png)
Follow the recent inclusive terminology guidelines and replace the word "slave" in vmaster API. I chose the word "follower" at this time since it seems fitting for the purpose. Note that the word "master" is kept in API, since it refers rather to audio master volume control. Also, while we're at it, a typo in comments is corrected, too. Link: https://lore.kernel.org/r/20200717154517.27599-1-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de>
521 lines
14 KiB
C
521 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Virtual master and follower controls
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*
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* Copyright (c) 2008 by Takashi Iwai <tiwai@suse.de>
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*/
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#include <linux/slab.h>
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#include <linux/export.h>
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#include <sound/core.h>
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#include <sound/control.h>
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#include <sound/tlv.h>
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/*
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* a subset of information returned via ctl info callback
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*/
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struct link_ctl_info {
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snd_ctl_elem_type_t type; /* value type */
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int count; /* item count */
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int min_val, max_val; /* min, max values */
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};
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/*
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* link master - this contains a list of follower controls that are
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* identical types, i.e. info returns the same value type and value
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* ranges, but may have different number of counts.
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*
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* The master control is so far only mono volume/switch for simplicity.
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* The same value will be applied to all followers.
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*/
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struct link_master {
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struct list_head followers;
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struct link_ctl_info info;
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int val; /* the master value */
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unsigned int tlv[4];
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void (*hook)(void *private_data, int);
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void *hook_private_data;
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};
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/*
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* link follower - this contains a follower control element
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*
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* It fakes the control callbacks with additional attenuation by the
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* master control. A follower may have either one or two channels.
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*/
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struct link_follower {
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struct list_head list;
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struct link_master *master;
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struct link_ctl_info info;
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int vals[2]; /* current values */
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unsigned int flags;
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struct snd_kcontrol *kctl; /* original kcontrol pointer */
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struct snd_kcontrol follower; /* the copy of original control entry */
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};
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static int follower_update(struct link_follower *follower)
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{
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struct snd_ctl_elem_value *uctl;
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int err, ch;
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uctl = kzalloc(sizeof(*uctl), GFP_KERNEL);
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if (!uctl)
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return -ENOMEM;
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uctl->id = follower->follower.id;
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err = follower->follower.get(&follower->follower, uctl);
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if (err < 0)
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goto error;
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for (ch = 0; ch < follower->info.count; ch++)
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follower->vals[ch] = uctl->value.integer.value[ch];
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error:
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kfree(uctl);
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return err < 0 ? err : 0;
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}
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/* get the follower ctl info and save the initial values */
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static int follower_init(struct link_follower *follower)
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{
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struct snd_ctl_elem_info *uinfo;
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int err;
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if (follower->info.count) {
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/* already initialized */
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if (follower->flags & SND_CTL_FOLLOWER_NEED_UPDATE)
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return follower_update(follower);
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return 0;
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}
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uinfo = kmalloc(sizeof(*uinfo), GFP_KERNEL);
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if (!uinfo)
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return -ENOMEM;
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uinfo->id = follower->follower.id;
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err = follower->follower.info(&follower->follower, uinfo);
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if (err < 0) {
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kfree(uinfo);
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return err;
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}
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follower->info.type = uinfo->type;
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follower->info.count = uinfo->count;
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if (follower->info.count > 2 ||
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(follower->info.type != SNDRV_CTL_ELEM_TYPE_INTEGER &&
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follower->info.type != SNDRV_CTL_ELEM_TYPE_BOOLEAN)) {
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pr_err("ALSA: vmaster: invalid follower element\n");
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kfree(uinfo);
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return -EINVAL;
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}
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follower->info.min_val = uinfo->value.integer.min;
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follower->info.max_val = uinfo->value.integer.max;
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kfree(uinfo);
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return follower_update(follower);
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}
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/* initialize master volume */
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static int master_init(struct link_master *master)
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{
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struct link_follower *follower;
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if (master->info.count)
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return 0; /* already initialized */
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list_for_each_entry(follower, &master->followers, list) {
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int err = follower_init(follower);
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if (err < 0)
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return err;
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master->info = follower->info;
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master->info.count = 1; /* always mono */
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/* set full volume as default (= no attenuation) */
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master->val = master->info.max_val;
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if (master->hook)
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master->hook(master->hook_private_data, master->val);
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return 1;
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}
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return -ENOENT;
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}
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static int follower_get_val(struct link_follower *follower,
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struct snd_ctl_elem_value *ucontrol)
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{
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int err, ch;
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err = follower_init(follower);
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if (err < 0)
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return err;
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for (ch = 0; ch < follower->info.count; ch++)
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ucontrol->value.integer.value[ch] = follower->vals[ch];
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return 0;
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}
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static int follower_put_val(struct link_follower *follower,
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struct snd_ctl_elem_value *ucontrol)
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{
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int err, ch, vol;
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err = master_init(follower->master);
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if (err < 0)
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return err;
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switch (follower->info.type) {
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case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
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for (ch = 0; ch < follower->info.count; ch++)
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ucontrol->value.integer.value[ch] &=
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!!follower->master->val;
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break;
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case SNDRV_CTL_ELEM_TYPE_INTEGER:
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for (ch = 0; ch < follower->info.count; ch++) {
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/* max master volume is supposed to be 0 dB */
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vol = ucontrol->value.integer.value[ch];
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vol += follower->master->val - follower->master->info.max_val;
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if (vol < follower->info.min_val)
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vol = follower->info.min_val;
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else if (vol > follower->info.max_val)
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vol = follower->info.max_val;
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ucontrol->value.integer.value[ch] = vol;
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}
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break;
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}
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return follower->follower.put(&follower->follower, ucontrol);
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}
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/*
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* ctl callbacks for followers
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*/
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static int follower_info(struct snd_kcontrol *kcontrol,
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struct snd_ctl_elem_info *uinfo)
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{
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struct link_follower *follower = snd_kcontrol_chip(kcontrol);
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return follower->follower.info(&follower->follower, uinfo);
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}
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static int follower_get(struct snd_kcontrol *kcontrol,
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struct snd_ctl_elem_value *ucontrol)
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{
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struct link_follower *follower = snd_kcontrol_chip(kcontrol);
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return follower_get_val(follower, ucontrol);
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}
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static int follower_put(struct snd_kcontrol *kcontrol,
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struct snd_ctl_elem_value *ucontrol)
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{
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struct link_follower *follower = snd_kcontrol_chip(kcontrol);
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int err, ch, changed = 0;
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err = follower_init(follower);
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if (err < 0)
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return err;
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for (ch = 0; ch < follower->info.count; ch++) {
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if (follower->vals[ch] != ucontrol->value.integer.value[ch]) {
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changed = 1;
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follower->vals[ch] = ucontrol->value.integer.value[ch];
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}
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}
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if (!changed)
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return 0;
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err = follower_put_val(follower, ucontrol);
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if (err < 0)
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return err;
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return 1;
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}
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static int follower_tlv_cmd(struct snd_kcontrol *kcontrol,
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int op_flag, unsigned int size,
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unsigned int __user *tlv)
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{
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struct link_follower *follower = snd_kcontrol_chip(kcontrol);
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/* FIXME: this assumes that the max volume is 0 dB */
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return follower->follower.tlv.c(&follower->follower, op_flag, size, tlv);
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}
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static void follower_free(struct snd_kcontrol *kcontrol)
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{
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struct link_follower *follower = snd_kcontrol_chip(kcontrol);
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if (follower->follower.private_free)
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follower->follower.private_free(&follower->follower);
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if (follower->master)
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list_del(&follower->list);
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kfree(follower);
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}
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/*
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* Add a follower control to the group with the given master control
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*
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* All followers must be the same type (returning the same information
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* via info callback). The function doesn't check it, so it's your
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* responsibility.
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*
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* Also, some additional limitations:
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* - at most two channels
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* - logarithmic volume control (dB level), no linear volume
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* - master can only attenuate the volume, no gain
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*/
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int _snd_ctl_add_follower(struct snd_kcontrol *master,
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struct snd_kcontrol *follower,
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unsigned int flags)
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{
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struct link_master *master_link = snd_kcontrol_chip(master);
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struct link_follower *srec;
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srec = kzalloc(struct_size(srec, follower.vd, follower->count),
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GFP_KERNEL);
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if (!srec)
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return -ENOMEM;
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srec->kctl = follower;
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srec->follower = *follower;
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memcpy(srec->follower.vd, follower->vd, follower->count * sizeof(*follower->vd));
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srec->master = master_link;
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srec->flags = flags;
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/* override callbacks */
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follower->info = follower_info;
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follower->get = follower_get;
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follower->put = follower_put;
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if (follower->vd[0].access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK)
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follower->tlv.c = follower_tlv_cmd;
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follower->private_data = srec;
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follower->private_free = follower_free;
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list_add_tail(&srec->list, &master_link->followers);
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return 0;
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}
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EXPORT_SYMBOL(_snd_ctl_add_follower);
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/*
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* ctl callbacks for master controls
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*/
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static int master_info(struct snd_kcontrol *kcontrol,
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struct snd_ctl_elem_info *uinfo)
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{
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struct link_master *master = snd_kcontrol_chip(kcontrol);
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int ret;
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ret = master_init(master);
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if (ret < 0)
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return ret;
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uinfo->type = master->info.type;
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uinfo->count = master->info.count;
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uinfo->value.integer.min = master->info.min_val;
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uinfo->value.integer.max = master->info.max_val;
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return 0;
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}
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static int master_get(struct snd_kcontrol *kcontrol,
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struct snd_ctl_elem_value *ucontrol)
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{
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struct link_master *master = snd_kcontrol_chip(kcontrol);
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int err = master_init(master);
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if (err < 0)
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return err;
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ucontrol->value.integer.value[0] = master->val;
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return 0;
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}
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static int sync_followers(struct link_master *master, int old_val, int new_val)
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{
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struct link_follower *follower;
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struct snd_ctl_elem_value *uval;
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uval = kmalloc(sizeof(*uval), GFP_KERNEL);
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if (!uval)
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return -ENOMEM;
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list_for_each_entry(follower, &master->followers, list) {
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master->val = old_val;
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uval->id = follower->follower.id;
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follower_get_val(follower, uval);
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master->val = new_val;
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follower_put_val(follower, uval);
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}
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kfree(uval);
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return 0;
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}
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static int master_put(struct snd_kcontrol *kcontrol,
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struct snd_ctl_elem_value *ucontrol)
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{
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struct link_master *master = snd_kcontrol_chip(kcontrol);
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int err, new_val, old_val;
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bool first_init;
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err = master_init(master);
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if (err < 0)
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return err;
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first_init = err;
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old_val = master->val;
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new_val = ucontrol->value.integer.value[0];
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if (new_val == old_val)
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return 0;
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err = sync_followers(master, old_val, new_val);
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if (err < 0)
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return err;
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if (master->hook && !first_init)
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master->hook(master->hook_private_data, master->val);
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return 1;
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}
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static void master_free(struct snd_kcontrol *kcontrol)
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{
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struct link_master *master = snd_kcontrol_chip(kcontrol);
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struct link_follower *follower, *n;
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/* free all follower links and retore the original follower kctls */
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list_for_each_entry_safe(follower, n, &master->followers, list) {
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struct snd_kcontrol *sctl = follower->kctl;
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struct list_head olist = sctl->list;
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memcpy(sctl, &follower->follower, sizeof(*sctl));
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memcpy(sctl->vd, follower->follower.vd,
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sctl->count * sizeof(*sctl->vd));
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sctl->list = olist; /* keep the current linked-list */
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kfree(follower);
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}
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kfree(master);
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}
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/**
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* snd_ctl_make_virtual_master - Create a virtual master control
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* @name: name string of the control element to create
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* @tlv: optional TLV int array for dB information
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*
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* Creates a virtual master control with the given name string.
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*
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* After creating a vmaster element, you can add the follower controls
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* via snd_ctl_add_follower() or snd_ctl_add_follower_uncached().
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*
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* The optional argument @tlv can be used to specify the TLV information
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* for dB scale of the master control. It should be a single element
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* with #SNDRV_CTL_TLVT_DB_SCALE, #SNDRV_CTL_TLV_DB_MINMAX or
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* #SNDRV_CTL_TLVT_DB_MINMAX_MUTE type, and should be the max 0dB.
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*
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* Return: The created control element, or %NULL for errors (ENOMEM).
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*/
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struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
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const unsigned int *tlv)
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{
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struct link_master *master;
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struct snd_kcontrol *kctl;
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struct snd_kcontrol_new knew;
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memset(&knew, 0, sizeof(knew));
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knew.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
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knew.name = name;
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knew.info = master_info;
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master = kzalloc(sizeof(*master), GFP_KERNEL);
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if (!master)
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return NULL;
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INIT_LIST_HEAD(&master->followers);
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kctl = snd_ctl_new1(&knew, master);
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if (!kctl) {
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kfree(master);
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return NULL;
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}
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/* override some callbacks */
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kctl->info = master_info;
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kctl->get = master_get;
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kctl->put = master_put;
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kctl->private_free = master_free;
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/* additional (constant) TLV read */
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if (tlv) {
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unsigned int type = tlv[SNDRV_CTL_TLVO_TYPE];
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if (type == SNDRV_CTL_TLVT_DB_SCALE ||
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type == SNDRV_CTL_TLVT_DB_MINMAX ||
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type == SNDRV_CTL_TLVT_DB_MINMAX_MUTE) {
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kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
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memcpy(master->tlv, tlv, sizeof(master->tlv));
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kctl->tlv.p = master->tlv;
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}
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}
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return kctl;
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}
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EXPORT_SYMBOL(snd_ctl_make_virtual_master);
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/**
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* snd_ctl_add_vmaster_hook - Add a hook to a vmaster control
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* @kcontrol: vmaster kctl element
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* @hook: the hook function
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* @private_data: the private_data pointer to be saved
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*
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* Adds the given hook to the vmaster control element so that it's called
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* at each time when the value is changed.
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*
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* Return: Zero.
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*/
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int snd_ctl_add_vmaster_hook(struct snd_kcontrol *kcontrol,
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void (*hook)(void *private_data, int),
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void *private_data)
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{
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struct link_master *master = snd_kcontrol_chip(kcontrol);
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master->hook = hook;
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master->hook_private_data = private_data;
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return 0;
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}
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EXPORT_SYMBOL_GPL(snd_ctl_add_vmaster_hook);
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/**
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* snd_ctl_sync_vmaster - Sync the vmaster followers and hook
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* @kcontrol: vmaster kctl element
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* @hook_only: sync only the hook
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*
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* Forcibly call the put callback of each follower and call the hook function
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* to synchronize with the current value of the given vmaster element.
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* NOP when NULL is passed to @kcontrol.
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*/
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void snd_ctl_sync_vmaster(struct snd_kcontrol *kcontrol, bool hook_only)
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{
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struct link_master *master;
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bool first_init = false;
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if (!kcontrol)
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return;
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master = snd_kcontrol_chip(kcontrol);
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if (!hook_only) {
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int err = master_init(master);
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if (err < 0)
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return;
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first_init = err;
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err = sync_followers(master, master->val, master->val);
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if (err < 0)
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return;
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}
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if (master->hook && !first_init)
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master->hook(master->hook_private_data, master->val);
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}
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EXPORT_SYMBOL_GPL(snd_ctl_sync_vmaster);
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/**
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* snd_ctl_apply_vmaster_followers - Apply function to each vmaster follower
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* @kctl: vmaster kctl element
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* @func: function to apply
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* @arg: optional function argument
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*
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* Apply the function @func to each follower kctl of the given vmaster kctl.
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* Returns 0 if successful, or a negative error code.
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*/
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int snd_ctl_apply_vmaster_followers(struct snd_kcontrol *kctl,
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int (*func)(struct snd_kcontrol *vfollower,
|
|
struct snd_kcontrol *follower,
|
|
void *arg),
|
|
void *arg)
|
|
{
|
|
struct link_master *master;
|
|
struct link_follower *follower;
|
|
int err;
|
|
|
|
master = snd_kcontrol_chip(kctl);
|
|
err = master_init(master);
|
|
if (err < 0)
|
|
return err;
|
|
list_for_each_entry(follower, &master->followers, list) {
|
|
err = func(follower->kctl, &follower->follower, arg);
|
|
if (err < 0)
|
|
return err;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(snd_ctl_apply_vmaster_followers);
|