ASoC: Add support for BCM2835

This driver adds support for digital audio (I2S)
for the BCM2835 SoC that is used by the
Raspberry Pi. External audio codecs can be
connected to the Raspberry Pi via P5 header.

It relies on cyclic DMA engine support for BCM2835.

Signed-off-by: Florian Meier <florian.meier@koalo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/sound/bcm2835-i2s.txt b/Documentation/devicetree/bindings/sound/bcm2835-i2s.txt
new file mode 100644
index 0000000..65783de
--- /dev/null
+++ b/Documentation/devicetree/bindings/sound/bcm2835-i2s.txt
@@ -0,0 +1,25 @@
+* Broadcom BCM2835 SoC I2S/PCM module
+
+Required properties:
+- compatible: "brcm,bcm2835-i2s"
+- reg: A list of base address and size entries:
+	* The first entry should cover the PCM registers
+	* The second entry should cover the PCM clock registers
+- dmas: List of DMA controller phandle and DMA request line ordered pairs.
+- dma-names: Identifier string for each DMA request line in the dmas property.
+  These strings correspond 1:1 with the ordered pairs in dmas.
+
+  One of the DMA channels will be responsible for transmission (should be
+  named "tx") and one for reception (should be named "rx").
+
+Example:
+
+bcm2835_i2s: i2s@7e203000 {
+	compatible = "brcm,bcm2835-i2s";
+	reg = <0x7e203000 0x20>,
+	      <0x7e101098 0x02>;
+
+	dmas = <&dma 2>,
+	       <&dma 3>;
+	dma-names = "tx", "rx";
+};