Kernel-3.10.0-957.el7_of-serial

• UART (Universal Asynchronous Receiver/Transmitter)

Required properties:

• compatible : one of:
  • “ns8250”
  • “ns16450”
  • “ns16550a”
  • “ns16550”
  • “ns16750”
  • “ns16850”
  • “nvidia,tegra20-uart”
  • “nxp,lpc3220-uart”
  • “ibm,qpace-nwp-serial”
  • “altr,16550-FIFO32”
  • “altr,16550-FIFO64”
  • “altr,16550-FIFO128”
  • “serial” if the port type is unknown.
• reg : offset and length of the register set for the device.
• interrupts : should contain uart interrupt.
• clock-frequency : the input clock frequency for the UART
  or
  clocks phandle to refer to the clk used as per Documentation/devicetree
  /bindings/clock/clock-bindings.txt

Optional properties:

• current-speed : the current active speed of the UART.
• reg-offset : offset to apply to the mapbase from the start of the registers.
• reg-shift : quantity to shift the register offsets by.
• reg-io-width : the size (in bytes) of the IO accesses that should be
  performed on the device. There are some systems that require 32-bit
  accesses to the UART (e.g. TI davinci).
• used-by-rtas : set to indicate that the port is in use by the OpenFirmware
  RTAS and should not be registered.
• no-loopback-test: set to indicate that the port does not implements loopback
  test mode
• fifo-size: the fifo size of the UART.
• auto-flow-control: one way to enable automatic flow control support. The
  driver is allowed to detect support for the capability even without this
  property.

Example:

uart@80230000 {
    compatible = "ns8250";
    reg = <0x80230000 0x100>;
    clock-frequency = <3686400>;
    interrupts = <10>;
    reg-shift = <2>;
};