openwrt/target/linux/ramips/patches-3.8/0012-Document-devicetree-add-OF-documents-for-MIPS-interr.patch

From dcc7310e144c3bf17a86d2f058d60fb525d4b34a Mon Sep 17 00:00:00 2001
From: John Crispin <blogic@openwrt.org>
Date: Thu, 31 Jan 2013 13:44:10 +0100
Subject: [PATCH 12/14] Document: devicetree: add OF documents for MIPS
 interrupt controller

Signed-off-by: John Crispin <blogic@openwrt.org>
Acked-by: David Daney <david.daney@cavium.com>
Patchwork: http://patchwork.linux-mips.org/patch/4901/
---
 Documentation/devicetree/bindings/mips/cpu_irq.txt |   47 ++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mips/cpu_irq.txt

--- /dev/null
+++ b/Documentation/devicetree/bindings/mips/cpu_irq.txt
@@ -0,0 +1,47 @@
+MIPS CPU interrupt controller
+
+On MIPS the mips_cpu_intc_init() helper can be used to initialize the 8 CPU
+IRQs from a devicetree file and create a irq_domain for IRQ controller.
+
+With the irq_domain in place we can describe how the 8 IRQs are wired to the
+platforms internal interrupt controller cascade.
+
+Below is an example of a platform describing the cascade inside the devicetree
+and the code used to load it inside arch_init_irq().
+
+Required properties:
+- compatible : Should be "mti,cpu-interrupt-controller"
+
+Example devicetree:
+	cpu-irq: cpu-irq@0 {
+		#address-cells = <0>;
+
+		interrupt-controller;
+		#interrupt-cells = <1>;
+
+		compatible = "mti,cpu-interrupt-controller";
+	};
+
+	intc: intc@200 {
+		compatible = "ralink,rt2880-intc";
+		reg = <0x200 0x100>;
+
+		interrupt-controller;
+		#interrupt-cells = <1>;
+
+		interrupt-parent = <&cpu-irq>;
+		interrupts = <2>;
+	};
+
+
+Example platform irq.c:
+static struct of_device_id __initdata of_irq_ids[] = {
+	{ .compatible = "mti,cpu-interrupt-controller", .data = mips_cpu_intc_init },
+	{ .compatible = "ralink,rt2880-intc", .data = intc_of_init },
+	{},
+};
+
+void __init arch_init_irq(void)
+{
+	of_irq_init(of_irq_ids);
+}