i2c: imx: add DMA support for freescale i2c driver

Add dma support for i2c. This function depend on DMA driver.
You can turn on it by write both the dmas and dma-name properties in dts node.
DMA is optional, even DMA request unsuccessfully, i2c can also work well.

Signed-off-by: Yuan Yao <yao.yuan@freescale.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

1 files changed, 11 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/i2c/i2c-imx.txt b/Documentation/devicetree/bindings/i2c/i2c-imx.txt
index 4a8513e44740..52d37fd8d3e5 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-imx.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-imx.txt
@@ -11,6 +11,8 @@ Required properties:
 Optional properties:
 - clock-frequency : Constains desired I2C/HS-I2C bus clock frequency in Hz.
   The absence of the propoerty indicates the default frequency 100 kHz.
+- dmas: A list of two dma specifiers, one for each entry in dma-names.
+- dma-names: should contain "tx" and "rx".
 
 Examples:
 
@@ -26,3 +28,12 @@ i2c@70038000 { /* HS-I2C on i.MX51 */
         interrupts = <64>;
         clock-frequency = <400000>;
 };
+
+i2c0: i2c@40066000 { /* i2c0 on vf610 */
+        compatible = "fsl,vf610-i2c";
+        reg = <0x40066000 0x1000>;
+        interrupts =<0 71 0x04>;
+        dmas = <&edma0 0 50>,
+                <&edma0 0 51>;
+        dma-names = "rx","tx";
+};