ALSA: hda - Make snd_hda_bus_type public

Define the common hd-audio driver and device types to bind over
snd_hda_bus_type publicly.  This allows to implement other type of
device and driver code over hd-audio bus.

Now both struct hda_codec and struct hda_codec_driver inherit these
new struct hdac_device and struct hdac_driver, respectively.

The bus registration is done in subsys_initcall() to assure it
before any other driver registrations.

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

3 files changed, 47 insertions, 0 deletions

diff --git a/sound/hda/Kconfig b/sound/hda/Kconfig
new file mode 100644
index 000000000000..4f428ccf64ad
--- /dev/null
+++ b/sound/hda/Kconfig
@@ -0,0 +1,2 @@
+config SND_HDA_CORE
+        tristate
diff --git a/sound/hda/Makefile b/sound/hda/Makefile
new file mode 100644
index 000000000000..59c8d1feb5aa
--- /dev/null
+++ b/sound/hda/Makefile
@@ -0,0 +1,3 @@
+snd-hda-core-objs := hda_bus_type.o
+
+obj-$(CONFIG_SND_HDA_CORE) += snd-hda-core.o
diff --git a/sound/hda/hda_bus_type.c b/sound/hda/hda_bus_type.c
new file mode 100644
index 000000000000..519914a12e8a
--- /dev/null
+++ b/sound/hda/hda_bus_type.c
@@ -0,0 +1,42 @@
+/*
+ * HD-audio bus
+ */
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/export.h>
+#include <sound/hdaudio.h>
+
+MODULE_DESCRIPTION("HD-audio bus");
+MODULE_LICENSE("GPL");
+
+static int hda_bus_match(struct device *dev, struct device_driver *drv)
+{
+        struct hdac_device *hdev = dev_to_hdac_dev(dev);
+        struct hdac_driver *hdrv = drv_to_hdac_driver(drv);
+
+        if (hdev->type != hdrv->type)
+                return 0;
+        if (hdrv->match)
+                return hdrv->match(hdev, hdrv);
+        return 1;
+}
+
+struct bus_type snd_hda_bus_type = {
+        .name = "hdaudio",
+        .match = hda_bus_match,
+};
+EXPORT_SYMBOL_GPL(snd_hda_bus_type);
+
+static int __init hda_bus_init(void)
+{
+        return bus_register(&snd_hda_bus_type);
+}
+
+static void __exit hda_bus_exit(void)
+{
+        bus_unregister(&snd_hda_bus_type);
+}
+
+subsys_initcall(hda_bus_init);
+module_exit(hda_bus_exit);