serial: mvebu-uart: initial support for Armada-3700 serial port

Armada-3700's uart is a simple serial port, which doesn't
support. Configuring the modem control lines. The uart port has a 32
bytes Tx FIFO and a 64 bytes Rx FIFO

The uart driver implements the uart core operations. It also support the
system (early) console based on Armada-3700's serial port.

Known Issue:

The uart driver currently doesn't support clock programming, which means
the baud-rate stays with the default value configured by the bootloader
at boot time

[gregory.clement@free-electrons.com: Rewrite many part which are too long
to enumerate]

Signed-off-by: Wilson Ding <dingwei@marvell.com>
Signed-off-by: Nadav Haklai <nadavh@marvell.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/tty/serial/mvebu-uart.txt b/Documentation/devicetree/bindings/tty/serial/mvebu-uart.txt
new file mode 100644
index 000000000000..6087defd9f93
--- /dev/null
+++ b/Documentation/devicetree/bindings/tty/serial/mvebu-uart.txt
@@ -0,0 +1,13 @@
+* Marvell UART : Non standard UART used in some of Marvell EBU SoCs (e.g., Armada-3700)
+
+Required properties:
+- compatible: "marvell,armada-3700-uart"
+- reg: offset and length of the register set for the device.
+- interrupts: device interrupt
+
+Example:
+	serial@12000 {
+		compatible = "marvell,armada-3700-uart";
+		reg = <0x12000 0x400>;
+		interrupts = <43>;
+	};