[PATCH 3/3] mfd: wm831x: Add device tree binding document

[Charles Keepax <ckeepax@opensource.wolfsonmicro.com>]

This is just a very simple initial binding, supporting only registering
the chip and the GPIOs. More features will be added as support for
device tree in the driver is expanded.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
---
 Documentation/devicetree/bindings/mfd/wm831x.txt | 31 ++++++++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mfd/wm831x.txt

diff --git a/Documentation/devicetree/bindings/mfd/wm831x.txt b/Documentation/devicetree/bindings/mfd/wm831x.txt
new file mode 100644
index 0000000..9771022
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/wm831x.txt
@@ -0,0 +1,31 @@
+Cirrus Logic/Wolfson Microelectronics wm831x PMICs
+
+System PMICs with a wide range of additional features.
+
+Required properties:
+
+  - compatible : One of the following chip-specific strings:
+        "wlf,wm8310"
+        "wlf,wm8311"
+        "wlf,wm8312"
+        "wlf,wm8320"
+        "wlf,wm8321"
+        "wlf,wm8325"
+        "wlf,wm8326"
+
+  - reg : I2C slave address when connected using I2C, chip select number when
+    using SPI.
+
+  - gpio-controller : Indicates this device is a GPIO controller.
+  - #gpio-cells : Must be 2. The first cell is the pin number and the
+    second cell is used to specify optional parameters (currently unused).
+
+Example:
+
+wm8310: wm8310@36 {
+	compatible = "wlf,wm8310";
+	reg = <0x36>;
+
+	gpio-controller;
+	#gpio-cells = <2>;
+};
-- 
2.1.4