doc: dt: add documentation for nxp,lpc1850-uart

Add device tree binding documentation for nxp,lpc1850-uart.

Signed-off-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/devicetree/bindings/serial/nxp,lpc1850-uart.txt b/Documentation/devicetree/bindings/serial/nxp,lpc1850-uart.txt
new file mode 100644 (file)
index 0000000..04e23e6
--- /dev/null
+++ b/Documentation/devicetree/bindings/serial/nxp,lpc1850-uart.txt
@@ -0,0 +1,28 @@
+* NXP LPC1850 UART
+
+Required properties:
+- compatible   : "nxp,lpc1850-uart", "ns16550a".
+- reg          : offset and length of the register set for the device.
+- interrupts   : should contain uart interrupt.
+- clocks       : phandle to the input clocks.
+- clock-names  : required elements: "uartclk", "reg".
+
+Optional properties:
+- dmas         : Two or more DMA channel specifiers following the
+                 convention outlined in bindings/dma/dma.txt
+- dma-names    : Names for the dma channels, if present. There must
+                 be at least one channel named "tx" for transmit
+                 and named "rx" for receive.
+
+Since it's also possible to also use the of_serial.c driver all
+parameters from 8250.txt also apply but are optional.
+
+Example:
+uart0: serial@40081000 {
+       compatible = "nxp,lpc1850-uart", "ns16550a";
+       reg = <0x40081000 0x1000>;
+       reg-shift = <2>;
+       interrupts = <24>;
+       clocks = <&ccu2 CLK_APB0_UART0>, <&ccu1 CLK_CPU_UART0>;
+       clock-names = "uartclk", "reg";
+};