[ALSA] ALSA sound driver for the AT73C213 DAC using Atmel SSC driver

This patch adds support for the AT73C213 DAC using the misc Atmel SSC driver in
I2S mode. The driver also requires a SPI to setup the registers and control
volume.
It has been tested with an AT32AP7000 on the ATSTK1000 development board. The
driver should also work with any Atmel device with an SSC module supported by
the Atmel SSC driver (atmel-ssc).
The atmel-ssc driver is just submitted to the Linux kernel. Please see mail
thread http://lkml.org/lkml/2007/7/16/32

Signed-off-by: Hans-Christian Egtvedt <hcegtvedt@atmel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>
diff --git a/sound/spi/Kconfig b/sound/spi/Kconfig
index 60fbb2a..0d08c29 100644
--- a/sound/spi/Kconfig
+++ b/sound/spi/Kconfig
@@ -3,4 +3,29 @@
 menu "SPI devices"
 	depends on SND != n
 
+config SND_AT73C213
+	tristate "Atmel AT73C213 DAC driver"
+	depends on ATMEL_SSC
+	select SND_PCM
+	help
+	  Say Y here if you want to use the Atmel AT73C213 external DAC. This
+	  DAC can be found on Atmel development boards.
+
+	  This driver requires the Atmel SSC driver for sound sink, a
+	  peripheral found on most AT91 and AVR32 microprocessors.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called snd-at73c213.
+
+config SND_AT73C213_TARGET_BITRATE
+	int "Target bitrate for AT73C213"
+	depends on SND_AT73C213
+	default "48000"
+	range 8000 50000
+	help
+	  Sets the target bitrate for the bitrate calculator in the driver.
+	  Limited by hardware to be between 8000 Hz and 50000 Hz.
+
+	  Set to 48000 Hz by default.
+
 endmenu