[PATCH V4 1/6] Documentation: DT: Add bindings for FSL NS16550A UART

[bhupesh.sharma@freescale.com (Bhupesh Sharma)]

This patch addss the device-tree documentation for Freescale's
NS16550 UART (also called DUART).

There is a specific errata fix required in FSL NS16550 UART
which ensures that an random interrupt storm is not observed when
a break is provided as an input to the UART.

Signed-off-by: Bhupesh Sharma <bhupesh.sharma@freescale.com>
---
 .../devicetree/bindings/serial/of-serial.txt       |   12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/Documentation/devicetree/bindings/serial/of-serial.txt b/Documentation/devicetree/bindings/serial/of-serial.txt
index 7705477..1bdc569 100644
--- a/Documentation/devicetree/bindings/serial/of-serial.txt
+++ b/Documentation/devicetree/bindings/serial/of-serial.txt
@@ -14,6 +14,7 @@ Required properties:
 	- "altr,16550-FIFO32"
 	- "altr,16550-FIFO64"
 	- "altr,16550-FIFO128"
+	- "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.
@@ -39,6 +40,17 @@ Optional properties:
   property.
 - has-hw-flow-control: the hardware has flow control capability.
 
+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 at 80230000 {
-- 
1.7.9.5