serial: fsl_lpuart: add DMA support

Add dma support for lpuart. This function depend on DMA driver.
You can turn on it by write both the dmas and dma-name properties in dts node.

Signed-off-by: Yuan Yao <yao.yuan@freescale.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 13 insertions, 4 deletions

diff --git a/Documentation/devicetree/bindings/serial/fsl-lpuart.txt b/Documentation/devicetree/bindings/serial/fsl-lpuart.txt
index 6fd1dd1638dd..b06e3053af9f 100644
--- a/Documentation/devicetree/bindings/serial/fsl-lpuart.txt
+++ b/Documentation/devicetree/bindings/serial/fsl-lpuart.txt
@@ -5,10 +5,19 @@ Required properties:
 - reg : Address and length of the register set for the device
 - interrupts : Should contain uart interrupt
 
+Optional properties:
+- dmas: A list of two dma specifiers, one for each entry in dma-names.
+- dma-names: should contain "tx" and "rx".
+
+Note: Optional properties for DMA support. Write them both or both not.
+
 Example:
 
 uart0: serial@40027000 {
-	       compatible = "fsl,vf610-lpuart";
-	       reg = <0x40027000 0x1000>;
-	       interrupts = <0 61 0x00>;
-       };
+		compatible = "fsl,vf610-lpuart";
+		reg = <0x40027000 0x1000>;
+		interrupts = <0 61 0x00>;
+		dmas = <&edma0 0 2>,
+			<&edma0 0 3>;
+		dma-names = "rx","tx";
+	};