Documentation/dt-bindings: Document STM32 EXTI controller bindings

Originally-from: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Signed-off-by: Alexandre TORGUE <alexandre.torgue@st.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: devicetree@vger.kernel.org
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: arnd@arndb.de
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: bruherrera@gmail.com
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-gpio@vger.kernel.org
Cc: Rob Herring <robh+dt@kernel.org>
Cc: lee.jones@linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1474387259-18926-2-git-send-email-alexandre.torgue@st.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Documentation/devicetree/bindings/interrupt-controller/st,stm32-exti.txt

@@ -0,0 +1,20 @@
+STM32 External Interrupt Controller
+
+Required properties:
+
+- compatible: Should be "st,stm32-exti"
+- reg: Specifies base physical address and size of the registers
+- interrupt-controller: Indentifies the node as an interrupt controller
+- #interrupt-cells: Specifies the number of cells to encode an interrupt
+  specifier, shall be 2
+- interrupts: interrupts references to primary interrupt controller
+
+Example:
+
+exti: interrupt-controller@40013c00 {
+	compatible = "st,stm32-exti";
+	interrupt-controller;
+	#interrupt-cells = <2>;
+	reg = <0x40013C00 0x400>;
+	interrupts = <1>, <2>, <3>, <6>, <7>, <8>, <9>, <10>, <23>, <40>, <41>, <42>, <62>, <76>;
+};