[PATCH RFC 1/9] ALSA: core: Introduce snd_device_alloc()

[Takashi Iwai <tiwai@suse.de>]

Introduce a new helper, snd_device_alloc(), for allocating a struct
device that is bound with the sound class.  It's a replacement of
snd_device_initialize().

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 include/sound/core.h |  1 +
 sound/core/init.c    | 31 +++++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/include/sound/core.h b/include/sound/core.h
index f6e0dd648b80..f986fcc5f18f 100644
--- a/include/sound/core.h
+++ b/include/sound/core.h
@@ -239,6 +239,7 @@ extern struct dentry *sound_debugfs_root;
 
 void snd_request_card(int card);
 
+int snd_device_alloc(struct device **dev_p, struct snd_card *card);
 void snd_device_initialize(struct device *dev, struct snd_card *card);
 
 int snd_register_device(int type, struct snd_card *card, int dev,
diff --git a/sound/core/init.c b/sound/core/init.c
index baef2688d0cf..a4de9f00d90f 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -134,6 +134,37 @@ void snd_device_initialize(struct device *dev, struct snd_card *card)
 }
 EXPORT_SYMBOL_GPL(snd_device_initialize);
 
+/* the default release callback set in snd_device_alloc() */
+static void default_release_alloc(struct device *dev)
+{
+	kfree(dev);
+}
+
+/**
+ * snd_device_alloc - Allocate and initialize struct device for sound devices
+ * @dev_p: pointer to store the allocated device
+ * @card: card to assign, optional
+ *
+ * For releasing the allocated device, call put_device().
+ */
+int snd_device_alloc(struct device **dev_p, struct snd_card *card)
+{
+	struct device *dev;
+
+	*dev_p = NULL;
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+	device_initialize(dev);
+	if (card)
+		dev->parent = &card->card_dev;
+	dev->class = &sound_class;
+	dev->release = default_release_alloc;
+	*dev_p = dev;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_device_alloc);
+
 static int snd_card_init(struct snd_card *card, struct device *parent,
 			 int idx, const char *xid, struct module *module,
 			 size_t extra_size);
-- 
2.35.3