From acc2097934b5403b97f95763fe99fc115b818061 Mon Sep 17 00:00:00 2001 From: Thierry Reding Date: Thu, 20 Sep 2012 14:16:50 +0200 Subject: [PATCH] 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 Cc: Grant Likely Acked-by: Stephen Warren Cc: devicetree-discuss@lists.ozlabs.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Thierry Reding Signed-off-by: Rob Herring --- .../bindings/interrupt-controller/interrupts.txt | 95 ++++++++++++++++++++++ 1 file changed, 95 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..72a06c0 --- /dev/null +++ b/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt @@ -0,0 +1,95 @@ +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>; + }; + }; -- 2.7.4