Documentation/devicetree/bindings/serial/atmel-usart.txt

   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         };