Documentation/devicetree/bindings/tty/serial/of-serial.txt

   1 * UART (Universal Asynchronous Receiver/Transmitter)
   2
   3 Required properties:
   4 - compatible : one of:
   5         - "ns8250"
   6         - "ns16450"
   7         - "ns16550a"
   8         - "ns16550"
   9         - "ns16750"
  10         - "ns16850"
  11         - "nvidia,tegra20-uart"
  12         - "nxp,lpc3220-uart"
  13         - "ibm,qpace-nwp-serial"
  14         - "serial" if the port type is unknown.
  15 - reg : offset and length of the register set for the device.
  16 - interrupts : should contain uart interrupt.
  17 - clock-frequency : the input clock frequency for the UART.
  18
  19 Optional properties:
  20 - current-speed : the current active speed of the UART.
  21 - reg-offset : offset to apply to the mapbase from the start of the registers.
  22 - reg-shift : quantity to shift the register offsets by.
  23 - reg-io-width : the size (in bytes) of the IO accesses that should be
  24   performed on the device.  There are some systems that require 32-bit
  25   accesses to the UART (e.g. TI davinci).
  26 - used-by-rtas : set to indicate that the port is in use by the OpenFirmware
  27   RTAS and should not be registered.
  28 - no-loopback-test: set to indicate that the port does not implements loopback
  29   test mode
  30
  31 Example:
  32
  33         uart@80230000 {
  34                 compatible = "ns8250";
  35                 reg = <0x80230000 0x100>;
  36                 clock-frequency = <3686400>;
  37                 interrupts = <10>;
  38                 reg-shift = <2>;
  39         };