Documentation: dma: Add documentation for ZTE DMA

This patch adds documentation for the ZTE ZX296702 SoC DMA device
DTS binding.

Signed-off-by: Jun Nie <jun.nie@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

diff --git a/Documentation/devicetree/bindings/dma/zxdma.txt b/Documentation/devicetree/bindings/dma/zxdma.txt
new file mode 100644 (file)
index 0000000..3207ceb
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/zxdma.txt
@@ -0,0 +1,38 @@
+* ZTE ZX296702 DMA controller
+
+Required properties:
+- compatible: Should be "zte,zx296702-dma"
+- reg: Should contain DMA registers location and length.
+- interrupts: Should contain one interrupt shared by all channel
+- #dma-cells: see dma.txt, should be 1, para number
+- dma-channels: physical channels supported
+- dma-requests: virtual channels supported, each virtual channel
+               have specific request line
+- clocks: clock required
+
+Example:
+
+Controller:
+       dma: dma-controller@0x09c00000{
+               compatible = "zte,zx296702-dma";
+               reg = <0x09c00000 0x1000>;
+               clocks = <&topclk ZX296702_DMA_ACLK>;
+               interrupts = <GIC_SPI 66 IRQ_TYPE_LEVEL_HIGH>;
+               #dma-cells = <1>;
+               dma-channels = <24>;
+               dma-requests = <24>;
+       };
+
+Client:
+Use specific request line passing from dmax
+For example, spdif0 tx channel request line is 4
+       spdif0: spdif0@0b004000 {
+               #sound-dai-cells = <0>;
+               compatible = "zte,zx296702-spdif";
+               reg = <0x0b004000 0x1000>;
+               clocks = <&lsp0clk ZX296702_SPDIF0_DIV>;
+               clock-names = "tx";
+               interrupts = <GIC_SPI 21 IRQ_TYPE_LEVEL_HIGH>;
+               dmas = <&dma 4>;
+               dma-names = "tx";
+       }