1 * UART (Universal Asynchronous Receiver/Transmitter)
11 - "nvidia,tegra20-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
19 clocks phandle to refer to the clk used as per Documentation/devicetree
20 /bindings/clock/clock-bindings.txt
23 - current-speed : the current active speed of the UART.
24 - reg-offset : offset to apply to the mapbase from the start of the registers.
25 - reg-shift : quantity to shift the register offsets by.
26 - reg-io-width : the size (in bytes) of the IO accesses that should be
27 performed on the device. There are some systems that require 32-bit
28 accesses to the UART (e.g. TI davinci).
29 - used-by-rtas : set to indicate that the port is in use by the OpenFirmware
30 RTAS and should not be registered.
31 - no-loopback-test: set to indicate that the port does not implements loopback
37 compatible = "ns8250";
38 reg = <0x80230000 0x100>;
39 clock-frequency = <3686400>;