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* 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.
- has-hw-flow-control: the hardware has flow control capability.
Example:
uart@80230000 {
compatible = "ns8250";
reg = <0x80230000 0x100>;
clock-frequency = <3686400>;
interrupts = <10>;
reg-shift = <2>;
};