ns16550: replace with binding files from Linux kernel

Replace ns16550.txt with binding files from Linux kernel. As suggested
by Stephen Warren, we should keep the directory structure, filenames,
and file content identical to the bindings in the Linux kernel.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Acked-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

1 files changed, 66 insertions, 0 deletions

diff --git a/doc/device-tree-bindings/serial/8250.txt b/doc/device-tree-bindings/serial/8250.txt
new file mode 100644
index 0000000..91d5ab0
--- /dev/null
+++ b/doc/device-tree-bindings/serial/8250.txt
@@ -0,0 +1,66 @@
+* UART (Universal Asynchronous Receiver/Transmitter)
+
+Required properties:
+- compatible : one of:
+	- "ns8250"
+	- "ns16450"
+	- "ns16550a"
+	- "ns16550"
+	- "ns16750"
+	- "ns16850"
+	- For Tegra20, must contain "nvidia,tegra20-uart"
+	- For other Tegra, must contain '"nvidia,<chip>-uart",
+	  "nvidia,tegra20-uart"' where <chip> is tegra30, tegra114, tegra124,
+	  tegra132, or tegra210.
+	- "nxp,lpc3220-uart"
+	- "ralink,rt2880-uart"
+	- "ibm,qpace-nwp-serial"
+	- "altr,16550-FIFO32"
+	- "altr,16550-FIFO64"
+	- "altr,16550-FIFO128"
+	- "fsl,16550-FIFO64"
+	- "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.
+- clock-frequency : the input clock frequency for the UART
+	 or
+  clocks phandle to refer to the clk used as per Documentation/devicetree
+  /bindings/clock/clock-bindings.txt
+
+Optional properties:
+- current-speed : the current active speed of the UART.
+- reg-offset : offset to apply to the mapbase from the start of the registers.
+- reg-shift : quantity to shift the register offsets by.
+- reg-io-width : the size (in bytes) of the IO accesses that should be
+  performed on the device.  There are some systems that require 32-bit
+  accesses to the UART (e.g. TI davinci).
+- used-by-rtas : set to indicate that the port is in use by the OpenFirmware
+  RTAS and should not be registered.
+- no-loopback-test: set to indicate that the port does not implements loopback
+  test mode
+- fifo-size: the fifo size of the UART.
+- auto-flow-control: one way to enable automatic flow control support. The
+  driver is allowed to detect support for the capability even without this
+  property.
+
+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@80230000 {
+		compatible = "ns8250";
+		reg = <0x80230000 0x100>;
+		clock-frequency = <3686400>;
+		interrupts = <10>;
+		reg-shift = <2>;
+	};