[PATCH v4 3/5] irqchip: Add DT binding doc for the virtual irq demuxer chip

[Boris Brezillon]

Add documentation for the virtual irq demuxer.

Signed-off-by: Boris Brezillon <boris.brezillon at free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre at atmel.com>
---
 .../bindings/interrupt-controller/dumb-demux.txt   | 41 ++++++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/interrupt-controller/dumb-demux.txt

diff --git a/Documentation/devicetree/bindings/interrupt-controller/dumb-demux.txt b/Documentation/devicetree/bindings/interrupt-controller/dumb-demux.txt
new file mode 100644
index 0000000..b9a7830
--- /dev/null
+++ b/Documentation/devicetree/bindings/interrupt-controller/dumb-demux.txt
@@ -0,0 +1,41 @@
+* Virtual Interrupt Demultiplexer
+
+This virtual demultiplexer simply forward all incoming interrupts to its
+enabled/unmasked children.
+It is only intended to be used by hardware that do not provide a proper way
+to demultiplex a source interrupt, and thus have to wake all their children
+up so that they can possibly handle the interrupt (if needed).
+This can be seen as an alternative to shared interrupts when at least one
+of the interrupt children is a timer (and require the irq to stay enabled
+on suspend) while others are not. This will prevent calling irq handlers of
+non timer devices while they are suspended.
+
+Required properties:
+- compatible: Should be "virtual,irq-demux".
+- interrupt-controller: Identifies the node as an interrupt controller.
+- interrupts-extended or interrupt-parent and interrupts: Reference the source
+  interrupt connected to this dumb demuxer.
+- #interrupt-cells: The number of cells to define the interrupts (should be 1).
+  The only cell is the IRQ number.
+- irqs: u32 bitfield specifying the interrupts provided by the demuxer.
+
+Examples:
+	/*
+	 * virtual demuxer controller
+	 */
+	virt_irq1_demux: virt-irq-demux at 1 {
+		compatible = "virtual,irq-demux";
+		interrupt-controller;
+		#interrupt-cells = <1>;
+		interrupts-extended = <&aic 1 IRQ_TYPE_LEVEL_HIGH 7>;
+		irqs = <0x3f>;
+	};
+
+	/*
+	 * Device connected on this dumb demuxer
+	 */
+	dma: dma-controller at ffffec00 {
+		compatible = "atmel,at91sam9g45-dma";
+		reg = <0xffffec00 0x200>;
+		interrupts-extended = <&virt_irq1_demux 0>;
+	};
-- 
1.9.1