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