dm: serial: Add driver model support for ns16550
Add driver model support so that ns16550 can support operation both with
and without driver model.
The driver needs a clock frequency so cannot stand alone unfortunately. The
clock frequency must be provided by a separate driver.
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/device-tree-bindings/serial/ns16550.txt b/doc/device-tree-bindings/serial/ns16550.txt
new file mode 100644
index 0000000..ef0b9ae
--- /dev/null
+++ b/doc/device-tree-bindings/serial/ns16550.txt
@@ -0,0 +1,10 @@
+NS16550 UART
+
+This UART driver supports many chip variants and is used in mamy SoCs.
+
+Required properties:
+- compatible: "ns16550" or "nvidia,tegra20-uart"
+- reg: start address and size of registers
+- reg-shift: shift value indicating register size: 0=byte, 1=16bit,2=32bit etc.
+- clock-frequency: input clock frequency for the UART (used to calculate the
+ baud rate divisor)