[mirror_ubuntu-artful-kernel.git] / sound / core / vmaster.c

/*
 * 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 <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];
};

/*
 * 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 = 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;
}

/* 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)) {
		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);

	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;
		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 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(sizeof(*srec) +
		       slave->count * sizeof(*slave->vd), 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 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, *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 matster control with the given name string.
 * Returns the created control element, or NULL for errors (ENOMEM).
 *
 * 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.
 */
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 ||
	     tlv[0] == SNDRV_CTL_TLVT_DB_MINMAX ||
	     tlv[0] == 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);
Commit	Line	Data
3b0a5f22 TI	1	/*
	2	* Virtual master and slave controls
	3	*
	4	* Copyright (c) 2008 by Takashi Iwai <tiwai@suse.de>
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License as
	8	* published by the Free Software Foundation, version 2.
	9	*
	10	*/
	11
	12	#include <linux/slab.h>
d81a6d71	13	#include <linux/export.h>
3b0a5f22 TI	14	#include <sound/core.h>
3b0a5f22 TI	15	#include <sound/control.h>
1c82ed1b	16	#include <sound/tlv.h>
3b0a5f22 TI	17
	18	/*
	19	* a subset of information returned via ctl info callback
	20	*/
	21	struct link_ctl_info {
fea952e5	22	snd_ctl_elem_type_t type; /* value type */
3b0a5f22 TI	23	int count; /* item count */
	24	int min_val, max_val; /* min, max values */
	25	};
	26
	27	/*
	28	* link master - this contains a list of slave controls that are
	29	* identical types, i.e. info returns the same value type and value
	30	* ranges, but may have different number of counts.
	31	*
	32	* The master control is so far only mono volume/switch for simplicity.
	33	* The same value will be applied to all slaves.
	34	*/
	35	struct link_master {
	36	struct list_head slaves;
	37	struct link_ctl_info info;
	38	int val; /* the master value */
1c82ed1b	39	unsigned int tlv[4];
3b0a5f22 TI	40	};
	41
	42	/*
	43	* link slave - this contains a slave control element
	44	*
	45	* It fakes the control callbacsk with additional attenuation by the
	46	* master control. A slave may have either one or two channels.
	47	*/
	48
	49	struct link_slave {
	50	struct list_head list;
	51	struct link_master *master;
	52	struct link_ctl_info info;
	53	int vals[2]; /* current values */
f5b1db63	54	unsigned int flags;
9e226b4b	55	struct snd_kcontrol kctl; / original kcontrol pointer */
3b0a5f22 TI	56	struct snd_kcontrol slave; /* the copy of original control entry */
	57	};
	58
f5b1db63 TI	59	static int slave_update(struct link_slave *slave)
	60	{
	61	struct snd_ctl_elem_value *uctl;
	62	int err, ch;
	63
	64	uctl = kmalloc(sizeof(*uctl), GFP_KERNEL);
	65	if (!uctl)
	66	return -ENOMEM;
	67	uctl->id = slave->slave.id;
	68	err = slave->slave.get(&slave->slave, uctl);
	69	for (ch = 0; ch < slave->info.count; ch++)
	70	slave->vals[ch] = uctl->value.integer.value[ch];
	71	kfree(uctl);
	72	return 0;
	73	}
	74
3b0a5f22 TI	75	/* get the slave ctl info and save the initial values */
	76	static int slave_init(struct link_slave *slave)
	77	{
	78	struct snd_ctl_elem_info *uinfo;
f5b1db63	79	int err;
3b0a5f22	80
f5b1db63 TI	81	if (slave->info.count) {
	82	/* already initialized */
	83	if (slave->flags & SND_CTL_SLAVE_NEED_UPDATE)
	84	return slave_update(slave);
	85	return 0;
	86	}
3b0a5f22 TI	87
	88	uinfo = kmalloc(sizeof(*uinfo), GFP_KERNEL);
	89	if (!uinfo)
	90	return -ENOMEM;
	91	uinfo->id = slave->slave.id;
	92	err = slave->slave.info(&slave->slave, uinfo);
	93	if (err < 0) {
	94	kfree(uinfo);
	95	return err;
	96	}
	97	slave->info.type = uinfo->type;
	98	slave->info.count = uinfo->count;
	99	if (slave->info.count > 2 \|\|
	100	(slave->info.type != SNDRV_CTL_ELEM_TYPE_INTEGER &&
	101	slave->info.type != SNDRV_CTL_ELEM_TYPE_BOOLEAN)) {
	102	snd_printk(KERN_ERR "invalid slave element\n");
	103	kfree(uinfo);
	104	return -EINVAL;
	105	}
	106	slave->info.min_val = uinfo->value.integer.min;
	107	slave->info.max_val = uinfo->value.integer.max;
	108	kfree(uinfo);
	109
f5b1db63	110	return slave_update(slave);
3b0a5f22 TI	111	}
	112
	113	/* initialize master volume */
	114	static int master_init(struct link_master *master)
	115	{
	116	struct link_slave *slave;
	117
	118	if (master->info.count)
	119	return 0; /* already initialized */
	120
	121	list_for_each_entry(slave, &master->slaves, list) {
	122	int err = slave_init(slave);
	123	if (err < 0)
	124	return err;
	125	master->info = slave->info;
	126	master->info.count = 1; /* always mono */
	127	/* set full volume as default (= no attenuation) */
	128	master->val = master->info.max_val;
	129	return 0;
	130	}
	131	return -ENOENT;
	132	}
	133
	134	static int slave_get_val(struct link_slave *slave,
	135	struct snd_ctl_elem_value *ucontrol)
	136	{
	137	int err, ch;
	138
	139	err = slave_init(slave);
	140	if (err < 0)
	141	return err;
	142	for (ch = 0; ch < slave->info.count; ch++)
	143	ucontrol->value.integer.value[ch] = slave->vals[ch];
	144	return 0;
	145	}
	146
	147	static int slave_put_val(struct link_slave *slave,
	148	struct snd_ctl_elem_value *ucontrol)
	149	{
	150	int err, ch, vol;
	151
	152	err = master_init(slave->master);
	153	if (err < 0)
	154	return err;
	155
	156	switch (slave->info.type) {
	157	case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
	158	for (ch = 0; ch < slave->info.count; ch++)
	159	ucontrol->value.integer.value[ch] &=
	160	!!slave->master->val;
	161	break;
	162	case SNDRV_CTL_ELEM_TYPE_INTEGER:
	163	for (ch = 0; ch < slave->info.count; ch++) {
	164	/* max master volume is supposed to be 0 dB */
	165	vol = ucontrol->value.integer.value[ch];
	166	vol += slave->master->val - slave->master->info.max_val;
	167	if (vol < slave->info.min_val)
	168	vol = slave->info.min_val;
	169	else if (vol > slave->info.max_val)
	170	vol = slave->info.max_val;
	171	ucontrol->value.integer.value[ch] = vol;
	172	}
	173	break;
	174	}
175	return slave->slave.put(&slave->slave, ucontrol);
176	}
177
178	/*
179	* ctl callbacks for slaves
180	*/
181	static int slave_info(struct snd_kcontrol *kcontrol,
182	struct snd_ctl_elem_info *uinfo)
183	{
184	struct link_slave *slave = snd_kcontrol_chip(kcontrol);
185	return slave->slave.info(&slave->slave, uinfo);
186	}
187
188	static int slave_get(struct snd_kcontrol *kcontrol,
189	struct snd_ctl_elem_value *ucontrol)
190	{
191	struct link_slave *slave = snd_kcontrol_chip(kcontrol);
192	return slave_get_val(slave, ucontrol);
193	}
194
195	static int slave_put(struct snd_kcontrol *kcontrol,
196	struct snd_ctl_elem_value *ucontrol)
197	{
198	struct link_slave *slave = snd_kcontrol_chip(kcontrol);
199	int err, ch, changed = 0;
200
201	err = slave_init(slave);
202	if (err < 0)
203	return err;
204	for (ch = 0; ch < slave->info.count; ch++) {
205	if (slave->vals[ch] != ucontrol->value.integer.value[ch]) {
206	changed = 1;
207	slave->vals[ch] = ucontrol->value.integer.value[ch];
208	}
209	}
210	if (!changed)
211	return 0;
212	return slave_put_val(slave, ucontrol);
213	}
214
215	static int slave_tlv_cmd(struct snd_kcontrol *kcontrol,
216	int op_flag, unsigned int size,
217	unsigned int __user *tlv)
218	{
219	struct link_slave *slave = snd_kcontrol_chip(kcontrol);
220	/* FIXME: this assumes that the max volume is 0 dB */
221	return slave->slave.tlv.c(&slave->slave, op_flag, size, tlv);
222	}
223
224	static void slave_free(struct snd_kcontrol *kcontrol)
225	{
226	struct link_slave *slave = snd_kcontrol_chip(kcontrol);
227	if (slave->slave.private_free)
228	slave->slave.private_free(&slave->slave);
229	if (slave->master)
230	list_del(&slave->list);
231	kfree(slave);
232	}
233
234	/*
235	* Add a slave control to the group with the given master control
236	*
237	* All slaves must be the same type (returning the same information
25985edc	238	* via info callback). The function doesn't check it, so it's your
3b0a5f22 TI	239	* responsibility.
	240	*
	241	* Also, some additional limitations:
	242	* - at most two channels
	243	* - logarithmic volume control (dB level), no linear volume
	244	* - master can only attenuate the volume, no gain
	245	*/
f5b1db63 TI	246	int _snd_ctl_add_slave(struct snd_kcontrol master, struct snd_kcontrol slave,
f5b1db63 TI	247	unsigned int flags)
3b0a5f22 TI	248	{
	249	struct link_master *master_link = snd_kcontrol_chip(master);
	250	struct link_slave *srec;
	251
	252	srec = kzalloc(sizeof(*srec) +
	253	slave->count * sizeof(*slave->vd), GFP_KERNEL);
	254	if (!srec)
	255	return -ENOMEM;
9e226b4b	256	srec->kctl = slave;
3b0a5f22 TI	257	srec->slave = *slave;
	258	memcpy(srec->slave.vd, slave->vd, slave->count * sizeof(*slave->vd));
	259	srec->master = master_link;
f5b1db63	260	srec->flags = flags;
3b0a5f22 TI	261
	262	/* override callbacks */
	263	slave->info = slave_info;
	264	slave->get = slave_get;
	265	slave->put = slave_put;
	266	if (slave->vd[0].access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK)
	267	slave->tlv.c = slave_tlv_cmd;
	268	slave->private_data = srec;
	269	slave->private_free = slave_free;
	270
	271	list_add_tail(&srec->list, &master_link->slaves);
	272	return 0;
	273	}
f5b1db63	274	EXPORT_SYMBOL(_snd_ctl_add_slave);
e922b002	275
3b0a5f22 TI	276	/*
	277	* ctl callbacks for master controls
	278	*/
	279	static int master_info(struct snd_kcontrol *kcontrol,
	280	struct snd_ctl_elem_info *uinfo)
	281	{
	282	struct link_master *master = snd_kcontrol_chip(kcontrol);
	283	int ret;
	284
	285	ret = master_init(master);
	286	if (ret < 0)
	287	return ret;
	288	uinfo->type = master->info.type;
	289	uinfo->count = master->info.count;
	290	uinfo->value.integer.min = master->info.min_val;
	291	uinfo->value.integer.max = master->info.max_val;
	292	return 0;
	293	}
	294
	295	static int master_get(struct snd_kcontrol *kcontrol,
	296	struct snd_ctl_elem_value *ucontrol)
	297	{
	298	struct link_master *master = snd_kcontrol_chip(kcontrol);
	299	int err = master_init(master);
	300	if (err < 0)
	301	return err;
	302	ucontrol->value.integer.value[0] = master->val;
	303	return 0;
	304	}
	305
	306	static int master_put(struct snd_kcontrol *kcontrol,
	307	struct snd_ctl_elem_value *ucontrol)
	308	{
	309	struct link_master *master = snd_kcontrol_chip(kcontrol);
	310	struct link_slave *slave;
	311	struct snd_ctl_elem_value *uval;
	312	int err, old_val;
	313
	314	err = master_init(master);
	315	if (err < 0)
	316	return err;
	317	old_val = master->val;
	318	if (ucontrol->value.integer.value[0] == old_val)
	319	return 0;
	320
	321	uval = kmalloc(sizeof(*uval), GFP_KERNEL);
	322	if (!uval)
	323	return -ENOMEM;
	324	list_for_each_entry(slave, &master->slaves, list) {
	325	master->val = old_val;
	326	uval->id = slave->slave.id;
	327	slave_get_val(slave, uval);
	328	master->val = ucontrol->value.integer.value[0];
	329	slave_put_val(slave, uval);
	330	}
	331	kfree(uval);
	332	return 1;
	333	}
	334
	335	static void master_free(struct snd_kcontrol *kcontrol)
	336	{
	337	struct link_master *master = snd_kcontrol_chip(kcontrol);
9e226b4b TI	338	struct link_slave slave, n;
	339
	340	/* free all slave links and retore the original slave kctls */
	341	list_for_each_entry_safe(slave, n, &master->slaves, list) {
	342	struct snd_kcontrol *sctl = slave->kctl;
	343	struct list_head olist = sctl->list;
	344	memcpy(sctl, &slave->slave, sizeof(*sctl));
	345	memcpy(sctl->vd, slave->slave.vd,
	346	sctl->count * sizeof(*sctl->vd));
	347	sctl->list = olist; /* keep the current linked-list */
	348	kfree(slave);
	349	}
3b0a5f22 TI	350	kfree(master);
	351	}
	352
	353
79c7cdd5 TI	354	/**
	355	* snd_ctl_make_virtual_master - Create a virtual master control
	356	* @name: name string of the control element to create
	357	* @tlv: optional TLV int array for dB information
	358	*
	359	* Creates a virtual matster control with the given name string.
	360	* Returns the created control element, or NULL for errors (ENOMEM).
	361	*
	362	* After creating a vmaster element, you can add the slave controls
	363	* via snd_ctl_add_slave() or snd_ctl_add_slave_uncached().
	364	*
	365	* The optional argument @tlv can be used to specify the TLV information
	366	* for dB scale of the master control. It should be a single element
085f3065 TI	367	* with #SNDRV_CTL_TLVT_DB_SCALE, #SNDRV_CTL_TLV_DB_MINMAX or
085f3065 TI	368	* #SNDRV_CTL_TLVT_DB_MINMAX_MUTE type, and should be the max 0dB.
3b0a5f22 TI	369	*/
	370	struct snd_kcontrol snd_ctl_make_virtual_master(char name,
	371	const unsigned int *tlv)
	372	{
	373	struct link_master *master;
	374	struct snd_kcontrol *kctl;
	375	struct snd_kcontrol_new knew;
	376
	377	memset(&knew, 0, sizeof(knew));
	378	knew.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
	379	knew.name = name;
	380	knew.info = master_info;
	381
	382	master = kzalloc(sizeof(*master), GFP_KERNEL);
	383	if (!master)
	384	return NULL;
	385	INIT_LIST_HEAD(&master->slaves);
	386
	387	kctl = snd_ctl_new1(&knew, master);
	388	if (!kctl) {
	389	kfree(master);
	390	return NULL;
	391	}
	392	/* override some callbacks */
	393	kctl->info = master_info;
	394	kctl->get = master_get;
	395	kctl->put = master_put;
	396	kctl->private_free = master_free;
	397
	398	/* additional (constant) TLV read */
085f3065 TI	399	if (tlv &&
	400	(tlv[0] == SNDRV_CTL_TLVT_DB_SCALE \|\|
	401	tlv[0] == SNDRV_CTL_TLVT_DB_MINMAX \|\|
	402	tlv[0] == SNDRV_CTL_TLVT_DB_MINMAX_MUTE)) {
3b0a5f22	403	kctl->vd[0].access \|= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
1c82ed1b TI	404	memcpy(master->tlv, tlv, sizeof(master->tlv));
1c82ed1b TI	405	kctl->tlv.p = master->tlv;
3b0a5f22	406	}
1c82ed1b	407
3b0a5f22 TI	408	return kctl;
3b0a5f22 TI	409	}
e922b002	410	EXPORT_SYMBOL(snd_ctl_make_virtual_master);