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+* UART (Universal Asynchronous Receiver/Transmitter)
+
+Required properties:
+- compatible : one of:
+ - "ns8250"
+ - "ns16450"
+ - "ns16550a"
+ - "ns16550"
+ - "ns16750"
+ - "ns16850"
+ - For Tegra20, must contain "nvidia,tegra20-uart"
+ - For other Tegra, must contain '"nvidia,<chip>-uart",
+ "nvidia,tegra20-uart"' where <chip> is tegra30, tegra114, tegra124,
+ tegra132, or tegra210.
+ - "nxp,lpc3220-uart"
+ - "ralink,rt2880-uart"
+ - "ibm,qpace-nwp-serial"
+ - "altr,16550-FIFO32"
+ - "altr,16550-FIFO64"
+ - "altr,16550-FIFO128"
+ - "fsl,16550-FIFO64"
+ - "fsl,ns16550"
+ - "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.
+
+Note:
+* fsl,ns16550:
+ ------------
+ Freescale DUART is very similar to the PC16552D (and to a
+ pair of NS16550A), albeit with some nonstandard behavior such as
+ erratum A-004737 (relating to incorrect BRK handling).
+
+ Represents a single port that is compatible with the DUART found
+ on many Freescale chips (examples include mpc8349, mpc8548,
+ mpc8641d, p4080 and ls2085a).
+
+Example:
+
+ uart@80230000 {
+ compatible = "ns8250";
+ reg = <0x80230000 0x100>;
+ clock-frequency = <3686400>;
+ interrupts = <10>;
+ reg-shift = <2>;
+ };