[ALSA] Move vmaster code to sound core

Move the codes for virtual master controls to sound core part so that
not only hda-intel drivers can use it.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

3 files changed, 373 insertions, 0 deletions

diff --git a/sound/core/Kconfig b/sound/core/Kconfig
index 829ca38..a8d71c6 100644
--- a/sound/core/Kconfig
+++ b/sound/core/Kconfig
@@ -181,3 +181,7 @@ config SND_PCM_XRUN_DEBUG
 	  It is usually not required, but if you have trouble with
 	  sound clicking when system is loaded, it may help to determine
 	  the process or driver which causes the scheduling gaps.
+
+config SND_VMASTER
+	bool
+	depends on SND
diff --git a/sound/core/Makefile b/sound/core/Makefile
index 267039a9..da8e685 100644
--- a/sound/core/Makefile
+++ b/sound/core/Makefile
@@ -6,6 +6,7 @@
 snd-y     := sound.o init.o memory.o info.o control.o misc.o device.o
 snd-$(CONFIG_ISA_DMA_API) += isadma.o
 snd-$(CONFIG_SND_OSSEMUL) += sound_oss.o info_oss.o
+snd-$(CONFIG_SND_VMASTER) += vmaster.o
 
 snd-pcm-objs := pcm.o pcm_native.o pcm_lib.o pcm_timer.o pcm_misc.o \
 		pcm_memory.o
diff --git a/sound/core/vmaster.c b/sound/core/vmaster.c
new file mode 100644
index 0000000..7cfd8b8
--- /dev/null
+++ b/sound/core/vmaster.c
@@ -0,0 +1,368 @@
+/*
+ * 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>
+
+/*
+ * 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 */
+};
+
+/*
+ * 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) {
+		/* FIXME: this assumes that the max volume is 0 dB */
+		kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
+		kctl->tlv.p = tlv;
+	}
+	return kctl;
+}
+
+EXPORT_SYMBOL(snd_ctl_make_virtual_master);