ASoC: Add dmaengine PCM helper functions

This patch adds a set of functions which are intended to be used when
implementing a dmaengine based sound PCM driver.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Vinod Koul <vinod.koul@linux.intel.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/Makefile b/sound/soc/Makefile
index 9ea8ac8..2feaf37 100644
--- a/sound/soc/Makefile
+++ b/sound/soc/Makefile
@@ -1,6 +1,9 @@
 snd-soc-core-objs := soc-core.o soc-dapm.o soc-jack.o soc-cache.o soc-utils.o
 snd-soc-core-objs += soc-pcm.o soc-io.o
 
+snd-soc-dmaengine-pcm-objs := soc-dmaengine-pcm.o
+obj-$(CONFIG_SND_SOC_DMAENGINE_PCM) += snd-soc-dmaengine-pcm.o
+
 obj-$(CONFIG_SND_SOC)	+= snd-soc-core.o
 obj-$(CONFIG_SND_SOC)	+= codecs/
 obj-$(CONFIG_SND_SOC)	+= atmel/