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linux-next/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
Grant Likely 79d9701559 of/irq: create interrupts-extended property
The standard interrupts property in device tree can only handle
interrupts coming from a single interrupt parent. If a device is wired
to multiple interrupt controllers, then it needs to be attached to a
node with an interrupt-map property to demux the interrupt specifiers
which is confusing. It would be a lot easier if there was a form of the
interrupts property that allows for a separate interrupt phandle for
each interrupt specifier.

This patch does exactly that by creating a new interrupts-extended
property which reuses the phandle+arguments pattern used by GPIOs and
other core bindings.

Signed-off-by: Grant Likely <grant.likely@linaro.org>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Kumar Gala <galak@codeaurora.org>
[grant.likely: removed versatile platform hunks into separate patch]
Cc: Rob Herring <rob.herring@calxeda.com>
2013-10-28 16:48:14 -07:00

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Specifying interrupt information for devices
============================================
1) Interrupt client nodes
-------------------------
Nodes that describe devices which generate interrupts must contain an either an
"interrupts" property or an "interrupts-extended" property. These properties
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.
Example:
interrupt-parent = <&intc1>;
interrupts = <5 0>, <6 0>;
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. Interrupts listed in the
"interrupts" property are always in reference to the node's interrupt parent.
The "interrupts-extended" property is a special form for use when a node needs
to reference multiple interrupt parents. Each entry in this property contains
both the parent phandle and the interrupt specifier. "interrupts-extended"
should only be used when a device has multiple interrupt parents.
Example:
interrupts-extended = <&intc1 5 1>, <&intc2 1 0>;
A device node may contain either "interrupts" or "interrupts-extended", but not
both. If both properties are present, then the operating system should log an
error and use only the data in "interrupts".
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>;
};
};