ALSA: ac97: add an ac97 bus

AC97 is a bus for sound usage. It enables for a AC97 AC-Link to link one
controller to 0 to 4 AC97 codecs.

The goal of this new implementation is to implement a device/driver
model for AC97, with an automatic scan of the bus and automatic
discovery of AC97 codec devices.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/sound/ac97/Kconfig b/sound/ac97/Kconfig
new file mode 100644
index 0000000..f8a64e1
--- /dev/null
+++ b/sound/ac97/Kconfig
@@ -0,0 +1,19 @@
+#
+# AC97 configuration
+#
+
+
+config AC97_BUS_NEW
+	tristate
+	select AC97
+	help
+	  This is the new AC97 bus type, successor of AC97_BUS. The ported
+	  drivers which benefit from the AC97 automatic probing should "select"
+	  this instead of the AC97_BUS.
+	  Say Y here if you want to have AC97 devices, which are sound oriented
+	  devices around an AC-Link.
+
+config AC97_BUS_COMPAT
+	bool
+	depends on AC97_BUS_NEW
+	depends on !AC97_BUS