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DEFINITIONS
This source file includes following definitions.
- slave_init
- master_init
- slave_get_val
- slave_put_val
- slave_info
- slave_get
- slave_put
- slave_tlv_cmd
- slave_free
- snd_ctl_add_slave
- master_info
- master_get
- master_put
- master_free
- snd_ctl_make_virtual_master
/*
* Virtual master and slave controls
*
* Copyright (c) 2008 by Takashi Iwai <tiwai@suse.de>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2.
*
*/
#include <linux/slab.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 {
int type; /* value type */
int count; /* item count */
int min_val, max_val; /* min, max values */
};
/*
* link master - this contains a list of slave 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 slaves.
*/
struct link_master {
struct list_head slaves;
struct link_ctl_info info;
int val; /* the master value */
unsigned int tlv[4];
};
/*
* link slave - this contains a slave control element
*
* It fakes the control callbacsk with additional attenuation by the
* master control. A slave may have either one or two channels.
*/
struct link_slave {
struct list_head list;
struct link_master *master;
struct link_ctl_info info;
int vals[2]; /* current values */
struct snd_kcontrol slave; /* the copy of original control entry */
};
/* get the slave ctl info and save the initial values */
static int slave_init(struct link_slave *slave)
{
struct snd_ctl_elem_info *uinfo;
struct snd_ctl_elem_value *uctl;
int err, ch;
if (slave->info.count)
return 0; /* already initialized */
uinfo = kmalloc(sizeof(*uinfo), GFP_KERNEL);
if (!uinfo)
return -ENOMEM;
uinfo->id = slave->slave.id;
err = slave->slave.info(&slave->slave, uinfo);
if (err < 0) {
kfree(uinfo);
return err;
}
slave->info.type = uinfo->type;
slave->info.count = uinfo->count;
if (slave->info.count > 2 ||
(slave->info.type != SNDRV_CTL_ELEM_TYPE_INTEGER &&
slave->info.type != SNDRV_CTL_ELEM_TYPE_BOOLEAN)) {
snd_printk(KERN_ERR "invalid slave element\n");
kfree(uinfo);
return -EINVAL;
}
slave->info.min_val = uinfo->value.integer.min;
slave->info.max_val = uinfo->value.integer.max;
kfree(uinfo);
uctl = kmalloc(sizeof(*uctl), GFP_KERNEL);
if (!uctl)
return -ENOMEM;
uctl->id = slave->slave.id;
err = slave->slave.get(&slave->slave, uctl);
for (ch = 0; ch < slave->info.count; ch++)
slave->vals[ch] = uctl->value.integer.value[ch];
kfree(uctl);
return 0;
}
/* initialize master volume */
static int master_init(struct link_master *master)
{
struct link_slave *slave;
if (master->info.count)
return 0; /* already initialized */
list_for_each_entry(slave, &master->slaves, list) {
int err = slave_init(slave);
if (err < 0)
return err;
master->info = slave->info;
master->info.count = 1; /* always mono */
/* set full volume as default (= no attenuation) */
master->val = master->info.max_val;
return 0;
}
return -ENOENT;
}
static int slave_get_val(struct link_slave *slave,
struct snd_ctl_elem_value *ucontrol)
{
int err, ch;
err = slave_init(slave);
if (err < 0)
return err;
for (ch = 0; ch < slave->info.count; ch++)
ucontrol->value.integer.value[ch] = slave->vals[ch];
return 0;
}
static int slave_put_val(struct link_slave *slave,
struct snd_ctl_elem_value *ucontrol)
{
int err, ch, vol;
err = master_init(slave->master);
if (err < 0)
return err;
switch (slave->info.type) {
case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
for (ch = 0; ch < slave->info.count; ch++)
ucontrol->value.integer.value[ch] &=
!!slave->master->val;
break;
case SNDRV_CTL_ELEM_TYPE_INTEGER:
for (ch = 0; ch < slave->info.count; ch++) {
/* max master volume is supposed to be 0 dB */
vol = ucontrol->value.integer.value[ch];
vol += slave->master->val - slave->master->info.max_val;
if (vol < slave->info.min_val)
vol = slave->info.min_val;
else if (vol > slave->info.max_val)
vol = slave->info.max_val;
ucontrol->value.integer.value[ch] = vol;
}
break;
}
return slave->slave.put(&slave->slave, ucontrol);
}
/*
* ctl callbacks for slaves
*/
static int slave_info(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_info *uinfo)
{
struct link_slave *slave = snd_kcontrol_chip(kcontrol);
return slave->slave.info(&slave->slave, uinfo);
}
static int slave_get(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_value *ucontrol)
{
struct link_slave *slave = snd_kcontrol_chip(kcontrol);
return slave_get_val(slave, ucontrol);
}
static int slave_put(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_value *ucontrol)
{
struct link_slave *slave = snd_kcontrol_chip(kcontrol);
int err, ch, changed = 0;
err = slave_init(slave);
if (err < 0)
return err;
for (ch = 0; ch < slave->info.count; ch++) {
if (slave->vals[ch] != ucontrol->value.integer.value[ch]) {
changed = 1;
slave->vals[ch] = ucontrol->value.integer.value[ch];
}
}
if (!changed)
return 0;
return slave_put_val(slave, ucontrol);
}
static int slave_tlv_cmd(struct snd_kcontrol *kcontrol,
int op_flag, unsigned int size,
unsigned int __user *tlv)
{
struct link_slave *slave = snd_kcontrol_chip(kcontrol);
/* FIXME: this assumes that the max volume is 0 dB */
return slave->slave.tlv.c(&slave->slave, op_flag, size, tlv);
}
static void slave_free(struct snd_kcontrol *kcontrol)
{
struct link_slave *slave = snd_kcontrol_chip(kcontrol);
if (slave->slave.private_free)
slave->slave.private_free(&slave->slave);
if (slave->master)
list_del(&slave->list);
kfree(slave);
}
/*
* Add a slave control to the group with the given master control
*
* All slaves must be the same type (returning the same information
* via info callback). The fucntion 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_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave)
{
struct link_master *master_link = snd_kcontrol_chip(master);
struct link_slave *srec;
srec = kzalloc(sizeof(*srec) +
slave->count * sizeof(*slave->vd), GFP_KERNEL);
if (!srec)
return -ENOMEM;
srec->slave = *slave;
memcpy(srec->slave.vd, slave->vd, slave->count * sizeof(*slave->vd));
srec->master = master_link;
/* override callbacks */
slave->info = slave_info;
slave->get = slave_get;
slave->put = slave_put;
if (slave->vd[0].access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK)
slave->tlv.c = slave_tlv_cmd;
slave->private_data = srec;
slave->private_free = slave_free;
list_add_tail(&srec->list, &master_link->slaves);
return 0;
}
EXPORT_SYMBOL(snd_ctl_add_slave);
/*
* 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 master_put(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_value *ucontrol)
{
struct link_master *master = snd_kcontrol_chip(kcontrol);
struct link_slave *slave;
struct snd_ctl_elem_value *uval;
int err, old_val;
err = master_init(master);
if (err < 0)
return err;
old_val = master->val;
if (ucontrol->value.integer.value[0] == old_val)
return 0;
uval = kmalloc(sizeof(*uval), GFP_KERNEL);
if (!uval)
return -ENOMEM;
list_for_each_entry(slave, &master->slaves, list) {
master->val = old_val;
uval->id = slave->slave.id;
slave_get_val(slave, uval);
master->val = ucontrol->value.integer.value[0];
slave_put_val(slave, uval);
}
kfree(uval);
return 1;
}
static void master_free(struct snd_kcontrol *kcontrol)
{
struct link_master *master = snd_kcontrol_chip(kcontrol);
struct link_slave *slave;
list_for_each_entry(slave, &master->slaves, list)
slave->master = NULL;
kfree(master);
}
/*
* Create a virtual master control with the given name
*/
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->slaves);
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 && tlv[0] == SNDRV_CTL_TLVT_DB_SCALE) {
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);