dt-bindings: mfd: Add retu/tahvo ASIC chips bindings

There are Device Tree source files defining a device node for the
retu/tahvo I2C chip, but there isn't a DT binding document for it.

Signed-off-by: Javier Martinez Canillas <javier@dowhile0.org>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/Documentation/devicetree/bindings/mfd/retu.txt b/Documentation/devicetree/bindings/mfd/retu.txt
new file mode 100644 (file)
index 0000000..8762423
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/retu.txt
@@ -0,0 +1,25 @@
+* Device tree bindings for Nokia Retu and Tahvo multi-function device
+
+Retu and Tahvo are a multi-function devices found on Nokia Internet
+Tablets (770, N800 and N810). The Retu chip provides watchdog timer
+and power button control functionalities while Tahvo chip provides
+USB transceiver functionality.
+
+Required properties:
+- compatible:          "nokia,retu" or "nokia,tahvo"
+- reg:                 Specifies the CBUS slave address of the ASIC chip
+- interrupts:          The interrupt line the device is connected to
+- interrupt-parent:    The parent interrupt controller
+
+Example:
+
+cbus0 {
+       compatible = "i2c-cbus-gpio";
+       ...
+       retu: retu@1 {
+               compatible = "nokia,retu";
+               interrupt-parent = <&gpio4>;
+               interrupts = <12 IRQ_TYPE_EDGE_RISING>;
+               reg = <0x1>;
+       };
+};