In order to use a device as interrupt controller, it needs to be marked
with the DT interrupt-controller property. This commit adds rudimentary
documentation about the required standard properties and describes the
most commonly used interrupt specifiers.
Cc: Linus Walleij <linus.wall...@stericsson.com>
Cc: Grant Likely <grant.lik...@secretlab.ca>
Cc: Rob Herring <rob.herr...@calxeda.com>
Cc: devicetree-disc...@lists.ozlabs.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Thierry Reding <thierry.red...@avionic-design.de>
---
This patch is for Rob's tree as it documents the general bindings.
.../bindings/interrupt-controller/interrupts.txt | 94 ++++++++++++++++++++++
1 file changed, 94 insertions(+)
create mode 100644
Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
diff --git
a/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
b/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
new file mode 100644
index 0000000..6cafe3a
--- /dev/null
+++ b/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
@@ -0,0 +1,94 @@
+Specifying interrupt information for devices
+============================================
+
+1) Interrupt user nodes
+-----------------------
+
+A device that generates interrupts can specify the interrupt controller to
+which the interrupts are routed by passing the controller's phandle in the
+"interrupt-parent" property.
+
+The "interrupts" property is a list of specifiers that describe each of the
+interrupts. See section 2 below for details.
+
+2) Interrupt controller nodes
+-----------------------------
+
+A device is marked as an interrupt controller with the "interrupt-controller"
+property. This is a empty, boolean property. An additional "#interrupt-cells"
+property defines the number of cells needed to specify a single interrupt.
+
+It is the responsibility of the interrupt controller's binding to define the
+length and format of the interrupt specifier. The following two variants are
+commonly used:
+
+ a) one cell
+ -----------
+ The #interrupt-cells property is set to 1 and the single cell defines the
+ index of the interrupt within the controller.
+
+ Example:
+
+ vic: intc@10140000 {
+ compatible = "arm,versatile-vic";
+ interrupt-controller;
+ #interrupt-cells = <1>;
+ reg = <0x10140000 0x1000>;
+ };
+
+ sic: intc@10003000 {
+ compatible = "arm,versatile-sic";
+ interrupt-controller;
+ #interrupt-cells = <1>;
+ reg = <0x10003000 0x1000>;
+ interrupt-parent = <&vic>;
+ interrupts = <31>; /* Cascaded to vic */
+ };
+
+ b) two cells
+ ------------
+ The #interrupt-cells property is set to 2 and the first cell defines the
+ index of the interrupt within the controller, while the second cell is used
+ to specify any of the following 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
+
+ Example:
+
+ gpio: gpio {
+ compatible = "nvidia,tegra20-gpio";
+ reg = <0x6000d000 0x1000>;
+ interrupts = <0 32 0x04
+ 0 33 0x04
+ 0 34 0x04
+ 0 35 0x04
+ 0 55 0x04
+ 0 87 0x04
+ 0 89 0x04>;
+ #gpio-cells = <2>;
+ gpio-controller;
+ #interrupt-cells = <2>;
+ interrupt-controller;
+ };
+
+ i2c@7000c000 {
+ status = "okay";
+ clock-frequency = <400000>;
+
+ wm8903: wm8903@1a {
+ compatible = "wlf,wm8903";
+ reg = <0x1a>;
+ interrupt-parent = <&gpio>;
+ interrupts = <187 0x04>;
+
+ gpio-controller;
+ #gpio-cells = <2>;
+
+ micdet-cfg = <0>;
+ micdet-delay = <100>;
+ gpio-cfg = <0xffffffff 0xffffffff 0 0xffffffff
0xffffffff>;
+ };
+ };
--
1.7.12
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