serial: at91: add dma support in usart binding descriptions

Signed-off-by: Elen Song <elen.song@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 17 insertions, 1 deletions

diff --git a/Documentation/devicetree/bindings/tty/serial/atmel-usart.txt b/Documentation/devicetree/bindings/tty/serial/atmel-usart.txt
index a49d9a1d4ccf..2191dcb9f1da 100644
--- a/Documentation/devicetree/bindings/tty/serial/atmel-usart.txt
+++ b/Documentation/devicetree/bindings/tty/serial/atmel-usart.txt
@@ -10,13 +10,18 @@ Required properties:
 Optional properties:
 - atmel,use-dma-rx: use of PDC or DMA for receiving data
 - atmel,use-dma-tx: use of PDC or DMA for transmitting data
+- add dma bindings for dma transfer:
+        - dmas: DMA specifier, consisting of a phandle to DMA controller node,
+                memory peripheral interface and USART DMA channel ID, FIFO configuration.
+                Refer to dma.txt and atmel-dma.txt for details.
+        - dma-names: "rx" for RX channel, "tx" for TX channel.
 
 <chip> compatible description:
 - at91rm9200:  legacy USART support
 - at91sam9260: generic USART implementation for SAM9 SoCs
 
 Example:
-
+- use PDC:
         usart0: serial@fff8c000 {
                 compatible = "atmel,at91sam9260-usart";
                 reg = <0xfff8c000 0x4000>;
@@ -25,3 +30,14 @@ Example:
                 atmel,use-dma-tx;
         };
 
+- use DMA:
+        usart0: serial@f001c000 {
+                compatible = "atmel,at91sam9260-usart";
+                reg = <0xf001c000 0x100>;
+                interrupts = <12 4 5>;
+                atmel,use-dma-rx;
+                atmel,use-dma-tx;
+                dmas = <&dma0 2 0x3>,
+                       <&dma0 2 0x204>;
+                dma-names = "tx", "rx";
+        };