@@ -0,0 +1,87 @@
+Broadcom Cygnus GPIO Controller
+
+Required properties:
+
+- compatible:
+    Must be "brcm,cygnus-gpio"
+
+- reg:
+    Define the base and range of the I/O address space that contain the Cygnus
+GPIO controller registers
+
+- ngpios:
+    Total number of GPIOs the controller provides
+
+- linux,gpio-base:
+    Base GPIO number of this controller
+
+- #gpio-cells:
+    Must be two. The first cell is the GPIO pin number (within the
+controller's domain) and the second cell is used for the following:
+    bit[0]: polarity (0 for normal and 1 for inverted)
+    bit[18:16]: internal pull up/down: 0 - pull up/down disabled
+                                       1 - pull up enabled
+                                       2 - pull down enabled
+    bit[22:20]: drive strength: 0 - 2 mA
+                                1 - 4 mA
+                                2 - 6 mA
+                                3 - 8 mA
+                                4 - 10 mA
+                                5 - 12 mA
+                                6 - 14 mA
+                                7 - 16 mA
+
+- gpio-controller:
+    Specifies that the node is a GPIO controller
+
+Optional properties:
+
+- interrupt-controller:
+    Specifies that the node is an interrupt controller. Not all Cygnus GPIO
+interfaces support interrupt, e.g., the CRMU GPIO controller does not have its
+interrupt routed to the main processor's GIC
+
+- interrupts:
+    The interrupt outputs from the GPIO controller.
+
+- no-drv-strength:
+    Specifies the GPIO controller does not support drive strength configuration
+
+Example:
+	gpio_asiu: gpio at 180a5000 {
+		compatible = "brcm,cygnus-gpio";
+		reg = <0x180a5000 0x668>;
+		ngpios = <122>;
+		linux,gpio-base = <0>;
+		#gpio-cells = <2>;
+		gpio-controller;
+		interrupt-controller;
+		interrupts = <GIC_SPI 174 IRQ_TYPE_LEVEL_HIGH>;
+	};
+
+	gpio_crmu: gpio at 03024800 {
+		compatible = "brcm,cygnus-gpio";
+		reg = <0x03024800 0x50>;
+		ngpios = <6>;
+		linux,gpio-base = <146>;
+		#gpio-cells = <2>;
+		gpio-controller;
+		no-drv-strength;
+	};
+
+	/*
+	 * Touchscreen that uses the ASIU GPIO 100, with internal pull-up
+	 * enabled
+	 */
+	tsc {
+		...
+		...
+		gpio-event = <&gpio_asiu 100 0x10000>;
+	};
+
+	/* Bluetooth that uses the CRMU GPIO 2, with polarity inverted */
+	bluetooth {
+		...
+		...
+		bcm,rfkill-bank-sel = <&gpio_crmu 2 1>
+	}