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281dee6707
Each kernel doc comment expects the definition of the return value in a proper format. This patch adds or fixes the missing entries for the remaining ALSA core API functions. Link: https://lore.kernel.org/r/20220713104759.4365-8-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de>
522 lines
14 KiB
C
522 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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*
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* Return: 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,
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struct snd_kcontrol *follower,
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void *arg),
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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);
|