ASoC: atmel: add wm8904 based audio machine driver

Add wm8904 based audio machine driver for Atmel EK board

The following ek board based on it
  - at91sam9n12ek
  - sama5d3xek (d31, d33, d34, d35)

Signed-off-by: Bo Shen <voice.shen@atmel.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/sound/soc/atmel/Kconfig b/sound/soc/atmel/Kconfig
index 1c0b185..986323b 100644
--- a/sound/soc/atmel/Kconfig
+++ b/sound/soc/atmel/Kconfig
@@ -33,6 +33,16 @@
 	  Say Y if you want to add support for SoC audio on WM8731-based
 	  AT91sam9g20 evaluation board.
 
+config SND_ATMEL_SOC_WM8904
+	tristate "Atmel ASoC driver for boards using WM8904 codec"
+	depends on ARCH_AT91 && ATMEL_SSC && SND_ATMEL_SOC
+	select SND_ATMEL_SOC_SSC
+	select SND_ATMEL_SOC_DMA
+	select SND_SOC_WM8904
+	help
+	  Say Y if you want to add support for Atmel ASoC driver for boards using
+	  WM8904 codec.
+
 config SND_AT91_SOC_AFEB9260
 	tristate "SoC Audio support for AFEB9260 board"
 	depends on ARCH_AT91 && ATMEL_SSC && ARCH_AT91 && MACH_AFEB9260 && SND_ATMEL_SOC