[PATCH v8 3/5] i2c: aspeed: added documentation for Aspeed I2C driver

[Brendan Higgins]

Added device tree binding documentation for Aspeed I2C busses.

Signed-off-by: Brendan Higgins <brendanhiggins at google.com>
---
Changes for v2:
  - None
Changes for v3:
  - Removed reference to "bus" device tree param
Changes for v4:
  - None
Changes for v5:
  - None
Changes for v6:
  - Replaced the controller property with and interrupt controller, leaving only
    the busses in the I2C documentation.
Changes for v7:
  - Changed clock-frequency to bus-frequency in device tree
Changes for v8:
  - Added multi-master property to device tree
---
 .../devicetree/bindings/i2c/i2c-aspeed.txt         | 48 ++++++++++++++++++++++
 1 file changed, 48 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-aspeed.txt

diff --git a/Documentation/devicetree/bindings/i2c/i2c-aspeed.txt b/Documentation/devicetree/bindings/i2c/i2c-aspeed.txt
new file mode 100644
index 000000000000..bd6480b19535
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-aspeed.txt
@@ -0,0 +1,48 @@
+Device tree configuration for the I2C busses on the AST24XX and AST25XX SoCs.
+
+Required Properties:
+- #address-cells	: should be 1
+- #size-cells		: should be 0
+- reg			: address offset and range of bus
+- compatible		: should be "aspeed,ast2400-i2c-bus"
+			  or "aspeed,ast2500-i2c-bus"
+- clocks		: root clock of bus, should reference the APB
+			  clock
+- interrupts		: interrupt number
+- interrupt-parent	: interrupt controller for bus, should reference a
+			  aspeed,ast2400-i2c-ic or aspeed,ast2500-i2c-ic
+			  interrupt controller
+
+Optional Properties:
+- bus-frequency	: frequency of the bus clock in Hz defaults to 100 kHz when not
+		  specified
+- multi-master	: states that there is another master active on this bus.
+
+Example:
+
+i2c {
+	compatible = "simple-bus";
+	#address-cells = <1>;
+	#size-cells = <1>;
+	ranges = <0 0x1e78a000 0x1000>;
+
+	i2c_ic: interrupt-controller at 0 {
+		#interrupt-cells = <1>;
+		compatible = "aspeed,ast2400-i2c-ic";
+		reg = <0x0 0x40>;
+		interrupts = <12>;
+		interrupt-controller;
+	};
+
+	i2c0: i2c-bus at 40 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		#interrupt-cells = <1>;
+		reg = <0x40 0x40>;
+		compatible = "aspeed,ast2400-i2c-bus";
+		clocks = <&clk_apb>;
+		bus-frequency = <100000>;
+		interrupts = <0>;
+		interrupt-parent = <&i2c_ic>;
+	};
+};
-- 
2.13.0.219.gdb65acc882-goog