ALSA: Add ALSA driver for Atmel Audio Bitstream DAC

This patch adds ALSA support for the Audio Bistream DAC found on Atmel
AVR32 devices. The ABDAC is an Atmel IP which might show up on AT91
devices in the future, hence making a generic driver which can be
utilized by AT91 arch if needed.

Datasheet describing the ABDAC peripheral is available in the AT32AP7000
datasheet, http://www.atmel.com/dyn/products/datasheets.asp?family_id=682

Tested on ATSTK1006 + ATSTK1000 with a class D amplifier stage.

Signed-off-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/atmel/Kconfig

@@ -0,0 +1,11 @@
+menu "Atmel devices (AVR32 and AT91)"
+	depends on AVR32 || ARCH_AT91
+
+config SND_ATMEL_ABDAC
+	tristate "Atmel Audio Bitstream DAC (ABDAC) driver"
+	select SND_PCM
+	depends on DW_DMAC && AVR32
+	help
+	  ALSA sound driver for the Atmel Audio Bitstream DAC (ABDAC).
+
+endmenu

sound/atmel/Makefile

@@ -0,0 +1,3 @@
+snd-atmel-abdac-objs		:= abdac.o
+
+obj-$(CONFIG_SND_ATMEL_ABDAC)	+= snd-atmel-abdac.o