1 files changed, 93 insertions, 17 deletions

diff --git a/sound/core/vmaster.c b/sound/core/vmaster.c
index 130cfe677d6..6c58e6f73a0 100644
--- a/sound/core/vmaster.c
+++ b/sound/core/vmaster.c
@@ -37,6 +37,8 @@ struct link_master {
 	struct link_ctl_info info;
 	int val;		/* the master value */
 	unsigned int tlv[4];
+	void (*hook)(void *private_data, int);
+	void *hook_private_data;
 };
 
 /*
@@ -99,7 +101,7 @@ static int slave_init(struct link_slave *slave)
 	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");
+		pr_err("ALSA: vmaster: invalid slave element\n");
 		kfree(uinfo);
 		return -EINVAL;
 	}
@@ -126,7 +128,9 @@ static int master_init(struct link_master *master)
 		master->info.count = 1; /* always mono */
 		/* set full volume as default (= no attenuation) */
 		master->val = master->info.max_val;
-		return 0;
+		if (master->hook)
+			master->hook(master->hook_private_data, master->val);
+		return 1;
 	}
 	return -ENOENT;
 }
@@ -209,7 +213,10 @@ static int slave_put(struct snd_kcontrol *kcontrol,
 	}
 	if (!changed)
 		return 0;
-	return slave_put_val(slave, ucontrol);
+	err = slave_put_val(slave, ucontrol);
+	if (err < 0)
+		return err;
+	return 1;
 }
 
 static int slave_tlv_cmd(struct snd_kcontrol *kcontrol,
@@ -303,20 +310,10 @@ static int master_get(struct snd_kcontrol *kcontrol,
 	return 0;
 }
 
-static int master_put(struct snd_kcontrol *kcontrol,
-		      struct snd_ctl_elem_value *ucontrol)
+static int sync_slaves(struct link_master *master, int old_val, int new_val)
 {
-	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)
@@ -325,10 +322,34 @@ static int master_put(struct snd_kcontrol *kcontrol,
 		master->val = old_val;
 		uval->id = slave->slave.id;
 		slave_get_val(slave, uval);
-		master->val = ucontrol->value.integer.value[0];
+		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;
 }
 
@@ -356,8 +377,7 @@ static void master_free(struct snd_kcontrol *kcontrol)
  * @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).
+ * 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().
@@ -366,6 +386,8 @@ static void master_free(struct snd_kcontrol *kcontrol)
  * 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)
@@ -408,3 +430,57 @@ struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
 	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);