syscon: dt-bindings: Add documentation for Aspeed system control units

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Joel Stanley <joel@jms.id.au>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/Documentation/devicetree/bindings/mfd/aspeed-scu.txt b/Documentation/devicetree/bindings/mfd/aspeed-scu.txt
new file mode 100644 (file)
index 0000000..4fc5b83
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/aspeed-scu.txt
@@ -0,0 +1,18 @@
+The Aspeed System Control Unit manages the global behaviour of the SoC,
+configuring elements such as clocks, pinmux, and reset.
+
+Required properties:
+- compatible:  One of:
+               "aspeed,ast2400-scu", "syscon", "simple-mfd"
+               "aspeed,g4-scu", "syscon", "simple-mfd"
+               "aspeed,ast2500-scu", "syscon", "simple-mfd"
+               "aspeed,g5-scu", "syscon", "simple-mfd"
+
+- reg:         contains the offset and length of the SCU memory region
+
+Example:
+
+syscon: syscon@1e6e2000 {
+       compatible = "aspeed,ast2400-scu", "syscon", "simple-mfd";
+       reg = <0x1e6e2000 0x1a8>;
+};