This patch adds DT support for generic (MMIO) GPIO driver.

Signed-off-by: Alexander Shiyan <redacted>
---
 .../devicetree/bindings/gpio/gpio-generic.txt      | 25 ++++++++++++++
 drivers/gpio/gpio-generic.c                        | 40 +++++++++++++++-------
 2 files changed, 53 insertions(+), 12 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/gpio/gpio-generic.txt

diff --git a/Documentation/devicetree/bindings/gpio/gpio-generic.txt b/Documentation/devicetree/bindings/gpio/gpio-generic.txt
new file mode 100644
index 0000000..a9417ac
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-generic.txt

@@ -0,0 +1,25 @@
+Generic memory-mapped GPIO controller
+
+Required properties:
+- compatible: Should be "basic-mmio-gpio" or "basic-mmio-gpio-be".
+- reg: Physical base GPIO controller registers location and length.
+- reg-names: Should be the names of reg resources. Each register uses
+  its own reg name, so there should be as many reg names as referenced
+  registers:
+  "dat"		: Input/output register (Required),
+  "set"		: Register for set output bits (Optional),
+  "clr"		: Register for clear output bits (Optional),
+  "dirout"	: Register for setup direction as output (Optional),
+  "dirin"	: Register for setup direction as input (Optional).
+- gpio-controller: Marks the device node as a gpio controller.
+- #gpio-cells: Should be two.
+
+Example (Simple 8-bit memory cell):
+
+bgpio: gpio@20000000 {
+	compatible = "basic-mmio-gpio";
+	reg = <0x20000000 0x1>;
+	reg-names = "dat";
+	gpio-controller;
+	#gpio-cells = <2>;
+};