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+* Atmel Universal Synchronous Asynchronous Receiver/Transmitter (USART)
+
+Required properties:
+- compatible: Should be "atmel,<chip>-usart"
+ The compatible <chip> indicated will be the first SoC to support an
+ additional mode or an USART new feature.
+- reg: Should contain registers location and length
+- interrupts: Should contain interrupt
+
+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>;
+ interrupts = <7>;
+ atmel,use-dma-rx;
+ 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";
+ };