devicetree: serial: Add documentation for imx serial

Add documentation for imx serial.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Rob Herring <rob.herring@calxeda.com>

diff --git a/Documentation/devicetree/bindings/serial/fsl-imx-uart.txt b/Documentation/devicetree/bindings/serial/fsl-imx-uart.txt
new file mode 100644 (file)
index 0000000..c58573b
--- /dev/null
+++ b/Documentation/devicetree/bindings/serial/fsl-imx-uart.txt
@@ -0,0 +1,35 @@
+* Freescale i.MX UART controller
+
+Required properties:
+- compatible : should be "fsl,imx21-uart"
+- reg : Address and length of the register set for the device
+- interrupts : Should contain UART interrupt number
+
+Optional properties:
+- fsl,uart-has-rtscts: indicate that RTS/CTS signals are used
+
+Note: Each uart controller should have an alias correctly numbered
+in "aliases" node.
+
+Example:
+
+- From imx51.dtsi:
+aliases {
+       serial0 = &uart1;
+       serial1 = &uart2;
+       serial2 = &uart3;
+};
+
+uart1: serial@73fbc000 {
+       compatible = "fsl,imx51-uart", "fsl,imx21-uart";
+       reg = <0x73fbc000 0x4000>;
+       interrupts = <31>;
+       status = "disabled";
+}
+
+- From imx51-babbage.dts:
+uart1: serial@73fbc000 {
+       fsl,uart-has-rtscts;
+       status = "okay";
+};
+