1* Atmel Universal Synchronous Asynchronous Receiver/Transmitter (USART) 2 3Required properties: 4- compatible: Should be "atmel,<chip>-usart" or "atmel,<chip>-dbgu" 5 The compatible <chip> indicated will be the first SoC to support an 6 additional mode or an USART new feature. 7 For the dbgu UART, use "atmel,<chip>-dbgu", "atmel,<chip>-usart" 8- reg: Should contain registers location and length 9- interrupts: Should contain interrupt 10- clock-names: tuple listing input clock names. 11 Required elements: "usart" 12- clocks: phandles to input clocks. 13 14Optional properties: 15- atmel,use-dma-rx: use of PDC or DMA for receiving data 16- atmel,use-dma-tx: use of PDC or DMA for transmitting data 17- {rts,cts,dtr,dsr,rng,dcd}-gpios: specify a GPIO for RTS/CTS/DTR/DSR/RI/DCD line respectively. 18 It will use specified PIO instead of the peripheral function pin for the USART feature. 19 If unsure, don't specify this property. 20- add dma bindings for dma transfer: 21 - dmas: DMA specifier, consisting of a phandle to DMA controller node, 22 memory peripheral interface and USART DMA channel ID, FIFO configuration. 23 Refer to dma.txt and atmel-dma.txt for details. 24 - dma-names: "rx" for RX channel, "tx" for TX channel. 25- atmel,fifo-size: maximum number of data the RX and TX FIFOs can store for FIFO 26 capable USARTs. 27 28<chip> compatible description: 29- at91rm9200: legacy USART support 30- at91sam9260: generic USART implementation for SAM9 SoCs 31 32Example: 33- use PDC: 34 usart0: serial@fff8c000 { 35 compatible = "atmel,at91sam9260-usart"; 36 reg = <0xfff8c000 0x4000>; 37 interrupts = <7>; 38 clocks = <&usart0_clk>; 39 clock-names = "usart"; 40 atmel,use-dma-rx; 41 atmel,use-dma-tx; 42 rts-gpios = <&pioD 15 GPIO_ACTIVE_LOW>; 43 cts-gpios = <&pioD 16 GPIO_ACTIVE_LOW>; 44 dtr-gpios = <&pioD 17 GPIO_ACTIVE_LOW>; 45 dsr-gpios = <&pioD 18 GPIO_ACTIVE_LOW>; 46 dcd-gpios = <&pioD 20 GPIO_ACTIVE_LOW>; 47 rng-gpios = <&pioD 19 GPIO_ACTIVE_LOW>; 48 }; 49 50- use DMA: 51 usart0: serial@f001c000 { 52 compatible = "atmel,at91sam9260-usart"; 53 reg = <0xf001c000 0x100>; 54 interrupts = <12 4 5>; 55 clocks = <&usart0_clk>; 56 clock-names = "usart"; 57 atmel,use-dma-rx; 58 atmel,use-dma-tx; 59 dmas = <&dma0 2 0x3>, 60 <&dma0 2 0x204>; 61 dma-names = "tx", "rx"; 62 atmel,fifo-size = <32>; 63 }; 64