mfd: Add basic device tree binding for wm8994

Add a placeholder device tree binding for the wm8994 driver. At present
the binding is essentially null as none of the platform data is supported,
and at least some of that will depend on the pending regulator bindings.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/sound/wm8994.txt b/Documentation/devicetree/bindings/sound/wm8994.txt
new file mode 100644
index 000000000000..7a7eb1e7bda6
--- /dev/null
+++ b/Documentation/devicetree/bindings/sound/wm8994.txt
@@ -0,0 +1,18 @@
+WM1811/WM8994/WM8958 audio CODEC
+
+These devices support both I2C and SPI (configured with pin strapping
+on the board).
+
+Required properties:
+
+  - compatible : "wlf,wm1811", "wlf,wm8994", "wlf,wm8958"
+
+  - reg : the I2C address of the device for I2C, the chip select
+          number for SPI.
+
+Example:
+
+codec: wm8994@1a {
+	compatible = "wlf,wm8994";
+	reg = <0x1a>;
+};