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Based on kernel version 3.16. Page generated on 2014-08-06 21:38 EST.

1	* Atmel Universal Synchronous Asynchronous Receiver/Transmitter (USART)
2	
3	Required properties:
4	- compatible: Should be "atmel,<chip>-usart"
5	  The compatible <chip> indicated will be the first SoC to support an
6	  additional mode or an USART new feature.
7	- reg: Should contain registers location and length
8	- interrupts: Should contain interrupt
9	- clock-names: tuple listing input clock names.
10		Required elements: "usart"
11	- clocks: phandles to input clocks.
12	
13	Optional properties:
14	- atmel,use-dma-rx: use of PDC or DMA for receiving data
15	- atmel,use-dma-tx: use of PDC or DMA for transmitting data
16	- {rts,cts,dtr,dsr,rng,dcd}-gpios: specify a GPIO for RTS/CTS/DTR/DSR/RI/DCD line respectively.
17	  It will use specified PIO instead of the peripheral function pin for the USART feature.
18	  If unsure, don't specify this property.
19	- add dma bindings for dma transfer:
20		- dmas: DMA specifier, consisting of a phandle to DMA controller node,
21			memory peripheral interface and USART DMA channel ID, FIFO configuration.
22			Refer to dma.txt and atmel-dma.txt for details.
23		- dma-names: "rx" for RX channel, "tx" for TX channel.
24	
25	<chip> compatible description:
26	- at91rm9200:  legacy USART support
27	- at91sam9260: generic USART implementation for SAM9 SoCs
28	
29	Example:
30	- use PDC:
31		usart0: serial@fff8c000 {
32			compatible = "atmel,at91sam9260-usart";
33			reg = <0xfff8c000 0x4000>;
34			interrupts = <7>;
35			clocks = <&usart0_clk>;
36			clock-names = "usart";
37			atmel,use-dma-rx;
38			atmel,use-dma-tx;
39			rts-gpios = <&pioD 15 GPIO_ACTIVE_LOW>;
40			cts-gpios = <&pioD 16 GPIO_ACTIVE_LOW>;
41			dtr-gpios = <&pioD 17 GPIO_ACTIVE_LOW>;
42			dsr-gpios = <&pioD 18 GPIO_ACTIVE_LOW>;
43			dcd-gpios = <&pioD 20 GPIO_ACTIVE_LOW>;
44			rng-gpios = <&pioD 19 GPIO_ACTIVE_LOW>;
45		};
46	
47	- use DMA:
48		usart0: serial@f001c000 {
49			compatible = "atmel,at91sam9260-usart";
50			reg = <0xf001c000 0x100>;
51			interrupts = <12 4 5>;
52			clocks = <&usart0_clk>;
53			clock-names = "usart";
54			atmel,use-dma-rx;
55			atmel,use-dma-tx;
56			dmas = <&dma0 2 0x3>,
57			       <&dma0 2 0x204>;
58			dma-names = "tx", "rx";
59		};
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