[linux.git] / sound / core / vmaster.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Virtual master and slave 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 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];
	void (*hook)(void *private_data, int);
	void *hook_private_data;
};

/*
 * 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 */
	unsigned int flags;
	struct snd_kcontrol *kctl; /* original kcontrol pointer */
	struct snd_kcontrol slave; /* the copy of original control entry */
};

static int slave_update(struct link_slave *slave)
{
	struct snd_ctl_elem_value *uctl;
	int err, ch;

	uctl = kzalloc(sizeof(*uctl), GFP_KERNEL);
	if (!uctl)
		return -ENOMEM;
	uctl->id = slave->slave.id;
	err = slave->slave.get(&slave->slave, uctl);
	if (err < 0)
		goto error;
	for (ch = 0; ch < slave->info.count; ch++)
		slave->vals[ch] = uctl->value.integer.value[ch];
 error:
	kfree(uctl);
	return err < 0 ? err : 0;
}

/* get the slave ctl info and save the initial values */
static int slave_init(struct link_slave *slave)
{
	struct snd_ctl_elem_info *uinfo;
	int err;

	if (slave->info.count) {
		/* already initialized */
		if (slave->flags & SND_CTL_SLAVE_NEED_UPDATE)
			return slave_update(slave);
		return 0;
	}

	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)) {
		pr_err("ALSA: vmaster: 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);

	return slave_update(slave);
}

/* 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;
		if (master->hook)
			master->hook(master->hook_private_data, master->val);
		return 1;
	}
	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;
	err = slave_put_val(slave, ucontrol);
	if (err < 0)
		return err;
	return 1;
}

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 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_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave,
		       unsigned int flags)
{
	struct link_master *master_link = snd_kcontrol_chip(master);
	struct link_slave *srec;

	srec = kzalloc(struct_size(srec, slave.vd, slave->count),
		       GFP_KERNEL);
	if (!srec)
		return -ENOMEM;
	srec->kctl = slave;
	srec->slave = *slave;
	memcpy(srec->slave.vd, slave->vd, slave->count * sizeof(*slave->vd));
	srec->master = master_link;
	srec->flags = flags;

	/* 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 sync_slaves(struct link_master *master, int old_val, int new_val)
{
	struct link_slave *slave;
	struct snd_ctl_elem_value *uval;

	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 = new_val;
		slave_put_val(slave, uval);
	}
	kfree(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;

	err = sync_slaves(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_slave *slave, *n;

	/* free all slave links and retore the original slave kctls */
	list_for_each_entry_safe(slave, n, &master->slaves, list) {
		struct snd_kcontrol *sctl = slave->kctl;
		struct list_head olist = sctl->list;
		memcpy(sctl, &slave->slave, sizeof(*sctl));
		memcpy(sctl->vd, slave->slave.vd,
		       sctl->count * sizeof(*sctl->vd));
		sctl->list = olist; /* keep the current linked-list */
		kfree(slave);
	}
	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 slave controls
 * via snd_ctl_add_slave() or snd_ctl_add_slave_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->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) {
		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 slaves and hook
 * @kcontrol: vmaster kctl element
 * @hook_only: sync only the hook
 *
 * Forcibly call the put callback of each slave 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_slaves(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_slaves - Apply function to each vmaster slave
 * @kctl: vmaster kctl element
 * @func: function to apply
 * @arg: optional function argument
 *
 * Apply the function @func to each slave kctl of the given vmaster kctl.
 * Returns 0 if successful, or a negative error code.
 */
int snd_ctl_apply_vmaster_slaves(struct snd_kcontrol *kctl,
				 int (*func)(struct snd_kcontrol *vslave,
					     struct snd_kcontrol *slave,
					     void *arg),
				 void *arg)
{
	struct link_master *master;
	struct link_slave *slave;
	int err;

	master = snd_kcontrol_chip(kctl);
	err = master_init(master);
	if (err < 0)
		return err;
	list_for_each_entry(slave, &master->slaves, list) {
		err = func(slave->kctl, &slave->slave, arg);
		if (err < 0)
			return err;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(snd_ctl_apply_vmaster_slaves);
Commit	Line	Data
a10e763b	1	// SPDX-License-Identifier: GPL-2.0-only
3b0a5f22 TI	2	/*
	3	* Virtual master and slave controls
	4	*
	5	* Copyright (c) 2008 by Takashi Iwai <[email protected]>
3b0a5f22 TI	6	*/
	7
	8	#include <linux/slab.h>
d81a6d71	9	#include <linux/export.h>
3b0a5f22 TI	10	#include <sound/core.h>
3b0a5f22 TI	11	#include <sound/control.h>
1c82ed1b	12	#include <sound/tlv.h>
3b0a5f22 TI	13
	14	/*
	15	* a subset of information returned via ctl info callback
	16	*/
	17	struct link_ctl_info {
fea952e5	18	snd_ctl_elem_type_t type; /* value type */
3b0a5f22 TI	19	int count; /* item count */
	20	int min_val, max_val; /* min, max values */
	21	};
	22
	23	/*
	24	* link master - this contains a list of slave controls that are
	25	* identical types, i.e. info returns the same value type and value
	26	* ranges, but may have different number of counts.
	27	*
	28	* The master control is so far only mono volume/switch for simplicity.
	29	* The same value will be applied to all slaves.
	30	*/
	31	struct link_master {
	32	struct list_head slaves;
	33	struct link_ctl_info info;
	34	int val; /* the master value */
1c82ed1b	35	unsigned int tlv[4];
2ad787e9 TI	36	void (hook)(void private_data, int);
2ad787e9 TI	37	void *hook_private_data;
3b0a5f22 TI	38	};
	39
	40	/*
	41	* link slave - this contains a slave control element
	42	*
	43	* It fakes the control callbacsk with additional attenuation by the
	44	* master control. A slave may have either one or two channels.
	45	*/
	46
	47	struct link_slave {
	48	struct list_head list;
	49	struct link_master *master;
	50	struct link_ctl_info info;
	51	int vals[2]; /* current values */
f5b1db63	52	unsigned int flags;
9e226b4b	53	struct snd_kcontrol kctl; / original kcontrol pointer */
3b0a5f22 TI	54	struct snd_kcontrol slave; /* the copy of original control entry */
	55	};
	56
f5b1db63 TI	57	static int slave_update(struct link_slave *slave)
	58	{
	59	struct snd_ctl_elem_value *uctl;
	60	int err, ch;
	61
7a33a02f	62	uctl = kzalloc(sizeof(*uctl), GFP_KERNEL);
f5b1db63 TI	63	if (!uctl)
	64	return -ENOMEM;
	65	uctl->id = slave->slave.id;
	66	err = slave->slave.get(&slave->slave, uctl);
2e2c177c TI	67	if (err < 0)
2e2c177c TI	68	goto error;
f5b1db63 TI	69	for (ch = 0; ch < slave->info.count; ch++)
f5b1db63 TI	70	slave->vals[ch] = uctl->value.integer.value[ch];
2e2c177c	71	error:
f5b1db63	72	kfree(uctl);
2e2c177c	73	return err < 0 ? err : 0;
f5b1db63 TI	74	}
f5b1db63 TI	75
3b0a5f22 TI	76	/* get the slave ctl info and save the initial values */
	77	static int slave_init(struct link_slave *slave)
	78	{
	79	struct snd_ctl_elem_info *uinfo;
f5b1db63	80	int err;
3b0a5f22	81
f5b1db63 TI	82	if (slave->info.count) {
	83	/* already initialized */
	84	if (slave->flags & SND_CTL_SLAVE_NEED_UPDATE)
	85	return slave_update(slave);
	86	return 0;
	87	}
3b0a5f22 TI	88
	89	uinfo = kmalloc(sizeof(*uinfo), GFP_KERNEL);
	90	if (!uinfo)
	91	return -ENOMEM;
	92	uinfo->id = slave->slave.id;
	93	err = slave->slave.info(&slave->slave, uinfo);
	94	if (err < 0) {
	95	kfree(uinfo);
	96	return err;
	97	}
	98	slave->info.type = uinfo->type;
	99	slave->info.count = uinfo->count;
	100	if (slave->info.count > 2 \|\|
	101	(slave->info.type != SNDRV_CTL_ELEM_TYPE_INTEGER &&
	102	slave->info.type != SNDRV_CTL_ELEM_TYPE_BOOLEAN)) {
f2f9307a	103	pr_err("ALSA: vmaster: invalid slave element\n");
3b0a5f22 TI	104	kfree(uinfo);
	105	return -EINVAL;
	106	}
	107	slave->info.min_val = uinfo->value.integer.min;
	108	slave->info.max_val = uinfo->value.integer.max;
	109	kfree(uinfo);
	110
f5b1db63	111	return slave_update(slave);
3b0a5f22 TI	112	}
	113
	114	/* initialize master volume */
	115	static int master_init(struct link_master *master)
	116	{
	117	struct link_slave *slave;
	118
	119	if (master->info.count)
	120	return 0; /* already initialized */
	121
	122	list_for_each_entry(slave, &master->slaves, list) {
	123	int err = slave_init(slave);
	124	if (err < 0)
	125	return err;
	126	master->info = slave->info;
	127	master->info.count = 1; /* always mono */
	128	/* set full volume as default (= no attenuation) */
	129	master->val = master->info.max_val;
2ad787e9 TI	130	if (master->hook)
	131	master->hook(master->hook_private_data, master->val);
	132	return 1;
3b0a5f22 TI	133	}
	134	return -ENOENT;
	135	}
	136
	137	static int slave_get_val(struct link_slave *slave,
	138	struct snd_ctl_elem_value *ucontrol)
	139	{
	140	int err, ch;
	141
	142	err = slave_init(slave);
	143	if (err < 0)
	144	return err;
	145	for (ch = 0; ch < slave->info.count; ch++)
	146	ucontrol->value.integer.value[ch] = slave->vals[ch];
	147	return 0;
	148	}
	149
	150	static int slave_put_val(struct link_slave *slave,
	151	struct snd_ctl_elem_value *ucontrol)
	152	{
	153	int err, ch, vol;
	154
	155	err = master_init(slave->master);
	156	if (err < 0)
	157	return err;
	158
	159	switch (slave->info.type) {
	160	case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
	161	for (ch = 0; ch < slave->info.count; ch++)
	162	ucontrol->value.integer.value[ch] &=
	163	!!slave->master->val;
	164	break;
	165	case SNDRV_CTL_ELEM_TYPE_INTEGER:
	166	for (ch = 0; ch < slave->info.count; ch++) {
	167	/* max master volume is supposed to be 0 dB */
	168	vol = ucontrol->value.integer.value[ch];
	169	vol += slave->master->val - slave->master->info.max_val;
	170	if (vol < slave->info.min_val)
	171	vol = slave->info.min_val;
	172	else if (vol > slave->info.max_val)
	173	vol = slave->info.max_val;
	174	ucontrol->value.integer.value[ch] = vol;
	175	}
	176	break;
	177	}
	178	return slave->slave.put(&slave->slave, ucontrol);
	179	}
	180
	181	/*
	182	* ctl callbacks for slaves
	183	*/
	184	static int slave_info(struct snd_kcontrol *kcontrol,
	185	struct snd_ctl_elem_info *uinfo)
	186	{
	187	struct link_slave *slave = snd_kcontrol_chip(kcontrol);
	188	return slave->slave.info(&slave->slave, uinfo);
	189	}
	190
	191	static int slave_get(struct snd_kcontrol *kcontrol,
	192	struct snd_ctl_elem_value *ucontrol)
	193	{
	194	struct link_slave *slave = snd_kcontrol_chip(kcontrol);
	195	return slave_get_val(slave, ucontrol);
	196	}
197
198	static int slave_put(struct snd_kcontrol *kcontrol,
199	struct snd_ctl_elem_value *ucontrol)
200	{
201	struct link_slave *slave = snd_kcontrol_chip(kcontrol);
202	int err, ch, changed = 0;
203
204	err = slave_init(slave);
205	if (err < 0)
206	return err;
207	for (ch = 0; ch < slave->info.count; ch++) {
208	if (slave->vals[ch] != ucontrol->value.integer.value[ch]) {
209	changed = 1;
210	slave->vals[ch] = ucontrol->value.integer.value[ch];
211	}
212	}
213	if (!changed)
214	return 0;
2069d483 TI	215	err = slave_put_val(slave, ucontrol);
	216	if (err < 0)
	217	return err;
	218	return 1;
3b0a5f22 TI	219	}
	220
	221	static int slave_tlv_cmd(struct snd_kcontrol *kcontrol,
	222	int op_flag, unsigned int size,
	223	unsigned int __user *tlv)
	224	{
	225	struct link_slave *slave = snd_kcontrol_chip(kcontrol);
	226	/* FIXME: this assumes that the max volume is 0 dB */
	227	return slave->slave.tlv.c(&slave->slave, op_flag, size, tlv);
	228	}
	229
	230	static void slave_free(struct snd_kcontrol *kcontrol)
	231	{
	232	struct link_slave *slave = snd_kcontrol_chip(kcontrol);
	233	if (slave->slave.private_free)
	234	slave->slave.private_free(&slave->slave);
	235	if (slave->master)
	236	list_del(&slave->list);
	237	kfree(slave);
	238	}
	239
	240	/*
	241	* Add a slave control to the group with the given master control
	242	*
	243	* All slaves must be the same type (returning the same information
25985edc	244	* via info callback). The function doesn't check it, so it's your
3b0a5f22 TI	245	* responsibility.
	246	*
	247	* Also, some additional limitations:
	248	* - at most two channels
	249	* - logarithmic volume control (dB level), no linear volume
	250	* - master can only attenuate the volume, no gain
	251	*/
f5b1db63 TI	252	int _snd_ctl_add_slave(struct snd_kcontrol master, struct snd_kcontrol slave,
f5b1db63 TI	253	unsigned int flags)
3b0a5f22 TI	254	{
	255	struct link_master *master_link = snd_kcontrol_chip(master);
	256	struct link_slave *srec;
	257
acafe7e3 KC	258	srec = kzalloc(struct_size(srec, slave.vd, slave->count),
acafe7e3 KC	259	GFP_KERNEL);
3b0a5f22 TI	260	if (!srec)
3b0a5f22 TI	261	return -ENOMEM;
9e226b4b	262	srec->kctl = slave;
3b0a5f22 TI	263	srec->slave = *slave;
	264	memcpy(srec->slave.vd, slave->vd, slave->count * sizeof(*slave->vd));
	265	srec->master = master_link;
f5b1db63	266	srec->flags = flags;
3b0a5f22 TI	267
	268	/* override callbacks */
	269	slave->info = slave_info;
	270	slave->get = slave_get;
	271	slave->put = slave_put;
	272	if (slave->vd[0].access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK)
	273	slave->tlv.c = slave_tlv_cmd;
	274	slave->private_data = srec;
	275	slave->private_free = slave_free;
	276
	277	list_add_tail(&srec->list, &master_link->slaves);
	278	return 0;
	279	}
f5b1db63	280	EXPORT_SYMBOL(_snd_ctl_add_slave);
e922b002	281
3b0a5f22 TI	282	/*
	283	* ctl callbacks for master controls
	284	*/
	285	static int master_info(struct snd_kcontrol *kcontrol,
	286	struct snd_ctl_elem_info *uinfo)
	287	{
	288	struct link_master *master = snd_kcontrol_chip(kcontrol);
	289	int ret;
	290
	291	ret = master_init(master);
	292	if (ret < 0)
	293	return ret;
	294	uinfo->type = master->info.type;
	295	uinfo->count = master->info.count;
	296	uinfo->value.integer.min = master->info.min_val;
	297	uinfo->value.integer.max = master->info.max_val;
	298	return 0;
	299	}
	300
	301	static int master_get(struct snd_kcontrol *kcontrol,
	302	struct snd_ctl_elem_value *ucontrol)
	303	{
	304	struct link_master *master = snd_kcontrol_chip(kcontrol);
	305	int err = master_init(master);
	306	if (err < 0)
	307	return err;
	308	ucontrol->value.integer.value[0] = master->val;
	309	return 0;
	310	}
	311
1ca2f2ec	312	static int sync_slaves(struct link_master *master, int old_val, int new_val)
3b0a5f22	313	{
3b0a5f22 TI	314	struct link_slave *slave;
3b0a5f22 TI	315	struct snd_ctl_elem_value *uval;
3b0a5f22 TI	316
	317	uval = kmalloc(sizeof(*uval), GFP_KERNEL);
	318	if (!uval)
	319	return -ENOMEM;
	320	list_for_each_entry(slave, &master->slaves, list) {
	321	master->val = old_val;
	322	uval->id = slave->slave.id;
	323	slave_get_val(slave, uval);
1ca2f2ec	324	master->val = new_val;
3b0a5f22 TI	325	slave_put_val(slave, uval);
	326	}
	327	kfree(uval);
1ca2f2ec TI	328	return 0;
	329	}
	330
	331	static int master_put(struct snd_kcontrol *kcontrol,
	332	struct snd_ctl_elem_value *ucontrol)
	333	{
	334	struct link_master *master = snd_kcontrol_chip(kcontrol);
	335	int err, new_val, old_val;
	336	bool first_init;
	337
	338	err = master_init(master);
	339	if (err < 0)
	340	return err;
	341	first_init = err;
	342	old_val = master->val;
	343	new_val = ucontrol->value.integer.value[0];
	344	if (new_val == old_val)
	345	return 0;
	346
	347	err = sync_slaves(master, old_val, new_val);
	348	if (err < 0)
	349	return err;
1ba65ae4	350	if (master->hook && !first_init)
2ad787e9	351	master->hook(master->hook_private_data, master->val);
3b0a5f22 TI	352	return 1;
	353	}
	354
	355	static void master_free(struct snd_kcontrol *kcontrol)
	356	{
	357	struct link_master *master = snd_kcontrol_chip(kcontrol);
9e226b4b TI	358	struct link_slave slave, n;
	359
	360	/* free all slave links and retore the original slave kctls */
	361	list_for_each_entry_safe(slave, n, &master->slaves, list) {
	362	struct snd_kcontrol *sctl = slave->kctl;
	363	struct list_head olist = sctl->list;
	364	memcpy(sctl, &slave->slave, sizeof(*sctl));
	365	memcpy(sctl->vd, slave->slave.vd,
	366	sctl->count * sizeof(*sctl->vd));
	367	sctl->list = olist; /* keep the current linked-list */
	368	kfree(slave);
	369	}
3b0a5f22 TI	370	kfree(master);
	371	}
	372
	373
79c7cdd5 TI	374	/**
	375	* snd_ctl_make_virtual_master - Create a virtual master control
	376	* @name: name string of the control element to create
	377	* @tlv: optional TLV int array for dB information
	378	*
eb7c06e8	379	* Creates a virtual master control with the given name string.
79c7cdd5 TI	380	*
	381	* After creating a vmaster element, you can add the slave controls
	382	* via snd_ctl_add_slave() or snd_ctl_add_slave_uncached().
	383	*
	384	* The optional argument @tlv can be used to specify the TLV information
	385	* for dB scale of the master control. It should be a single element
085f3065 TI	386	* with #SNDRV_CTL_TLVT_DB_SCALE, #SNDRV_CTL_TLV_DB_MINMAX or
085f3065 TI	387	* #SNDRV_CTL_TLVT_DB_MINMAX_MUTE type, and should be the max 0dB.
eb7c06e8 YB	388	*
eb7c06e8 YB	389	* Return: The created control element, or %NULL for errors (ENOMEM).
3b0a5f22 TI	390	*/
	391	struct snd_kcontrol snd_ctl_make_virtual_master(char name,
	392	const unsigned int *tlv)
	393	{
	394	struct link_master *master;
	395	struct snd_kcontrol *kctl;
	396	struct snd_kcontrol_new knew;
	397
	398	memset(&knew, 0, sizeof(knew));
	399	knew.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
	400	knew.name = name;
	401	knew.info = master_info;
	402
	403	master = kzalloc(sizeof(*master), GFP_KERNEL);
	404	if (!master)
	405	return NULL;
	406	INIT_LIST_HEAD(&master->slaves);
	407
	408	kctl = snd_ctl_new1(&knew, master);
	409	if (!kctl) {
	410	kfree(master);
	411	return NULL;
	412	}
	413	/* override some callbacks */
	414	kctl->info = master_info;
	415	kctl->get = master_get;
	416	kctl->put = master_put;
	417	kctl->private_free = master_free;
	418
	419	/* additional (constant) TLV read */
841bdb7c TS	420	if (tlv) {
	421	unsigned int type = tlv[SNDRV_CTL_TLVO_TYPE];
	422	if (type == SNDRV_CTL_TLVT_DB_SCALE \|\|
	423	type == SNDRV_CTL_TLVT_DB_MINMAX \|\|
	424	type == SNDRV_CTL_TLVT_DB_MINMAX_MUTE) {
	425	kctl->vd[0].access \|= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
	426	memcpy(master->tlv, tlv, sizeof(master->tlv));
	427	kctl->tlv.p = master->tlv;
	428	}
3b0a5f22	429	}
1c82ed1b	430
3b0a5f22 TI	431	return kctl;
3b0a5f22 TI	432	}
e922b002	433	EXPORT_SYMBOL(snd_ctl_make_virtual_master);
2ad787e9 TI	434
	435	/**
	436	* snd_ctl_add_vmaster_hook - Add a hook to a vmaster control
	437	* @kcontrol: vmaster kctl element
	438	* @hook: the hook function
f2ec52d4	439	* @private_data: the private_data pointer to be saved
2ad787e9 TI	440	*
	441	* Adds the given hook to the vmaster control element so that it's called
	442	* at each time when the value is changed.
eb7c06e8 YB	443	*
eb7c06e8 YB	444	* Return: Zero.
2ad787e9 TI	445	*/
	446	int snd_ctl_add_vmaster_hook(struct snd_kcontrol *kcontrol,
	447	void (hook)(void private_data, int),
	448	void *private_data)
	449	{
	450	struct link_master *master = snd_kcontrol_chip(kcontrol);
	451	master->hook = hook;
	452	master->hook_private_data = private_data;
	453	return 0;
	454	}
	455	EXPORT_SYMBOL_GPL(snd_ctl_add_vmaster_hook);
	456
	457	/**
1ca2f2ec	458	* snd_ctl_sync_vmaster - Sync the vmaster slaves and hook
2ad787e9	459	* @kcontrol: vmaster kctl element
1ca2f2ec	460	* @hook_only: sync only the hook
2ad787e9	461	*
1ca2f2ec TI	462	* Forcibly call the put callback of each slave and call the hook function
	463	* to synchronize with the current value of the given vmaster element.
	464	* NOP when NULL is passed to @kcontrol.
2ad787e9	465	*/
1ca2f2ec	466	void snd_ctl_sync_vmaster(struct snd_kcontrol *kcontrol, bool hook_only)
2ad787e9 TI	467	{
2ad787e9 TI	468	struct link_master *master;
1ca2f2ec TI	469	bool first_init = false;
1ca2f2ec TI	470
2ad787e9 TI	471	if (!kcontrol)
	472	return;
	473	master = snd_kcontrol_chip(kcontrol);
1ca2f2ec TI	474	if (!hook_only) {
	475	int err = master_init(master);
	476	if (err < 0)
	477	return;
	478	first_init = err;
	479	err = sync_slaves(master, master->val, master->val);
	480	if (err < 0)
	481	return;
	482	}
	483
	484	if (master->hook && !first_init)
2ad787e9 TI	485	master->hook(master->hook_private_data, master->val);
2ad787e9 TI	486	}
1ca2f2ec	487	EXPORT_SYMBOL_GPL(snd_ctl_sync_vmaster);
a91d6612 TI	488
	489	/**
	490	* snd_ctl_apply_vmaster_slaves - Apply function to each vmaster slave
	491	* @kctl: vmaster kctl element
	492	* @func: function to apply
	493	* @arg: optional function argument
	494	*
	495	* Apply the function @func to each slave kctl of the given vmaster kctl.
	496	* Returns 0 if successful, or a negative error code.
	497	*/
	498	int snd_ctl_apply_vmaster_slaves(struct snd_kcontrol *kctl,
d6c0615f TI	499	int (func)(struct snd_kcontrol vslave,
	500	struct snd_kcontrol *slave,
	501	void *arg),
a91d6612 TI	502	void *arg)
	503	{
	504	struct link_master *master;
	505	struct link_slave *slave;
	506	int err;
	507
	508	master = snd_kcontrol_chip(kctl);
	509	err = master_init(master);
	510	if (err < 0)
	511	return err;
	512	list_for_each_entry(slave, &master->slaves, list) {
d6c0615f	513	err = func(slave->kctl, &slave->slave, arg);
a91d6612 TI	514	if (err < 0)
	515	return err;
	516	}
	517
	518	return 0;
	519	}
	520	EXPORT_SYMBOL_GPL(snd_ctl_apply_vmaster_slaves);