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authorThierry Reding <thierry.reding@avionic-design.de>2012-09-20 12:16:50 (GMT)
committerRob Herring <rob.herring@calxeda.com>2012-10-01 15:51:25 (GMT)
commitacc2097934b5403b97f95763fe99fc115b818061 (patch)
tree16fcdd6e3972821076e93017f256776d2f9512da /Documentation/devicetree/bindings/interrupt-controller
parent06455bbcab76e5f5225de5f38ab948d37a1c3587 (diff)
dt: Document general interrupt controller bindings
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.walleij@stericsson.com> Cc: Grant Likely <grant.likely@secretlab.ca> Acked-by: Stephen Warren <swarren@wwwdotorg.org> Cc: devicetree-discuss@lists.ozlabs.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de> Signed-off-by: Rob Herring <rob.herring@calxeda.com>
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+Specifying interrupt information for devices
+============================================
+
+1) Interrupt client nodes
+-------------------------
+
+Nodes that describe devices which generate interrupts must contain an
+"interrupts" property. This property must contain a list of interrupt
+specifiers, one per output interrupt. The format of the interrupt specifier is
+determined by the interrupt controller to which the interrupts are routed; see
+section 2 below for details.
+
+The "interrupt-parent" property is used to specify the controller to which
+interrupts are routed and contains a single phandle referring to the interrupt
+controller node. This property is inherited, so it may be specified in an
+interrupt client node or in any of its parent nodes.
+
+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:
+
+ i2c@7000c000 {
+ gpioext: gpio-adnp@41 {
+ compatible = "ad,gpio-adnp";
+ reg = <0x41>;
+
+ interrupt-parent = <&gpio>;
+ interrupts = <160 1>;
+
+ gpio-controller;
+ #gpio-cells = <1>;
+
+ interrupt-controller;
+ #interrupt-cells = <2>;
+
+ nr-gpios = <64>;
+ };
+
+ sx8634@2b {
+ compatible = "smtc,sx8634";
+ reg = <0x2b>;
+
+ interrupt-parent = <&gpioext>;
+ interrupts = <3 0x8>;
+
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ threshold = <0x40>;
+ sensitivity = <7>;
+ };
+ };

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