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" 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
  14 Optional 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
  32 Example:
  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         };