gpio: dt-bindings: add wd,mbl-gpio bindings

This patch adds the device tree bindings for the Western Digital's
MyBook Live memory-mapped GPIO controllers.

The gpios will be supported by gpio-mmio code of the
GPIO generic library.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/Documentation/devicetree/bindings/gpio/wd,mbl-gpio.txt b/Documentation/devicetree/bindings/gpio/wd,mbl-gpio.txt
new file mode 100644 (file)
index 0000000..038c3a6
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/wd,mbl-gpio.txt
@@ -0,0 +1,38 @@
+Bindings for the Western Digital's MyBook Live memory-mapped GPIO controllers.
+
+The Western Digital MyBook Live has two memory-mapped GPIO controllers.
+Both GPIO controller only have a single 8-bit data register, where GPIO
+state can be read and/or written.
+
+Required properties:
+       - compatible: should be "wd,mbl-gpio"
+       - reg-names: must contain
+               "dat" - data register
+       - reg: address + size pairs describing the GPIO register sets;
+               order must correspond with the order of entries in reg-names
+       - #gpio-cells: must be set to 2. The first cell is the pin number and
+                       the second cell is used to specify the gpio polarity:
+                       0 = active high
+                       1 = active low
+       - gpio-controller: Marks the device node as a gpio controller.
+
+Optional properties:
+       - no-output: GPIOs are read-only.
+
+Examples:
+       gpio0: gpio0@e0000000 {
+               compatible = "wd,mbl-gpio";
+               reg-names = "dat";
+               reg = <0xe0000000 0x1>;
+               #gpio-cells = <2>;
+               gpio-controller;
+       };
+
+       gpio1: gpio1@e0100000 {
+               compatible = "wd,mbl-gpio";
+               reg-names = "dat";
+               reg = <0xe0100000 0x1>;
+               #gpio-cells = <2>;
+               gpio-controller;
+               no-output;
+       };