1Specifying interrupt information for devices
2============================================
3
41) Interrupt client nodes
5-------------------------
6
7Nodes that describe devices which generate interrupts must contain an
8"interrupts" property, an "interrupts-extended" property, or both. If both are
9present, the latter should take precedence; the former may be provided simply
10for compatibility with software that does not recognize the latter. These
11properties contain a list of interrupt specifiers, one per output interrupt. The
12format of the interrupt specifier is determined by the interrupt controller to
13which the interrupts are routed; see section 2 below for details.
14
15  Example:
16	interrupt-parent = <&intc1>;
17	interrupts = <5 0>, <6 0>;
18
19The "interrupt-parent" property is used to specify the controller to which
20interrupts are routed and contains a single phandle referring to the interrupt
21controller node. This property is inherited, so it may be specified in an
22interrupt client node or in any of its parent nodes. Interrupts listed in the
23"interrupts" property are always in reference to the node's interrupt parent.
24
25The "interrupts-extended" property is a special form for use when a node needs
26to reference multiple interrupt parents. Each entry in this property contains
27both the parent phandle and the interrupt specifier. "interrupts-extended"
28should only be used when a device has multiple interrupt parents.
29
30  Example:
31	interrupts-extended = <&intc1 5 1>, <&intc2 1 0>;
32
33A device node may contain either "interrupts" or "interrupts-extended", but not
34both. If both properties are present, then the operating system should log an
35error and use only the data in "interrupts".
36
372) Interrupt controller nodes
38-----------------------------
39
40A device is marked as an interrupt controller with the "interrupt-controller"
41property. This is a empty, boolean property. An additional "#interrupt-cells"
42property defines the number of cells needed to specify a single interrupt.
43
44It is the responsibility of the interrupt controller's binding to define the
45length and format of the interrupt specifier. The following two variants are
46commonly used:
47
48  a) one cell
49  -----------
50  The #interrupt-cells property is set to 1 and the single cell defines the
51  index of the interrupt within the controller.
52
53  Example:
54
55	vic: intc@10140000 {
56		compatible = "arm,versatile-vic";
57		interrupt-controller;
58		#interrupt-cells = <1>;
59		reg = <0x10140000 0x1000>;
60	};
61
62	sic: intc@10003000 {
63		compatible = "arm,versatile-sic";
64		interrupt-controller;
65		#interrupt-cells = <1>;
66		reg = <0x10003000 0x1000>;
67		interrupt-parent = <&vic>;
68		interrupts = <31>; /* Cascaded to vic */
69	};
70
71  b) two cells
72  ------------
73  The #interrupt-cells property is set to 2 and the first cell defines the
74  index of the interrupt within the controller, while the second cell is used
75  to specify any of the following flags:
76    - bits[3:0] trigger type and level flags
77        1 = low-to-high edge triggered
78        2 = high-to-low edge triggered
79        4 = active high level-sensitive
80        8 = active low level-sensitive
81
82  Example:
83
84	i2c@7000c000 {
85		gpioext: gpio-adnp@41 {
86			compatible = "ad,gpio-adnp";
87			reg = <0x41>;
88
89			interrupt-parent = <&gpio>;
90			interrupts = <160 1>;
91
92			gpio-controller;
93			#gpio-cells = <1>;
94
95			interrupt-controller;
96			#interrupt-cells = <2>;
97
98			nr-gpios = <64>;
99		};
100
101		sx8634@2b {
102			compatible = "smtc,sx8634";
103			reg = <0x2b>;
104
105			interrupt-parent = <&gpioext>;
106			interrupts = <3 0x8>;
107
108			#address-cells = <1>;
109			#size-cells = <0>;
110
111			threshold = <0x40>;
112			sensitivity = <7>;
113		};
114	};
115