ARM: at91/aic: add irq domain and device tree support

Add an irqdomain for the AIC interrupt controller.
The device tree support is mapping the registers and
is using the irq_domain_add_legacy() to manage hwirq
translation.
The documentation is describing the meaning of the
two cells required for using this "interrupt-controller"
in a device tree node.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

1 files changed, 38 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/arm/atmel-aic.txt b/Documentation/devicetree/bindings/arm/atmel-aic.txt
new file mode 100644
index 000000000000..aabca4f83402
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/atmel-aic.txt
@@ -0,0 +1,38 @@
+* Advanced Interrupt Controller (AIC)
+
+Required properties:
+- compatible: Should be "atmel,<chip>-aic"
+- interrupt-controller: Identifies the node as an interrupt controller.
+- interrupt-parent: For single AIC system, it is an empty property.
+- #interrupt-cells: The number of cells to define the interrupts. It sould be 2.
+  The first cell is the IRQ number (aka "Peripheral IDentifier" on datasheet).
+  The second cell is used to specify flags:
+    bits[3:0] trigger type and level flags:
+      1 = low-to-high edge triggered.
+      2 = high-to-low edge triggered.
+      4 = active high level-sensitive.
+      8 = active low level-sensitive.
+      Valid combinations are 1, 2, 3, 4, 8.
+      Default flag for internal sources should be set to 4 (active high).
+- reg: Should contain AIC registers location and length
+
+Examples:
+        /*
+         * AIC
+         */
+        aic: interrupt-controller@fffff000 {
+                compatible = "atmel,at91rm9200-aic";
+                interrupt-controller;
+                interrupt-parent;
+                #interrupt-cells = <2>;
+                reg = <0xfffff000 0x200>;
+        };
+
+        /*
+         * An interrupt generating device that is wired to an AIC.
+         */
+        dma: dma-controller@ffffec00 {
+                compatible = "atmel,at91sam9g45-dma";
+                reg = <0xffffec00 0x200>;
+                interrupts = <21 4>;
+        };