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122 lines
3.8 KiB
122 lines
3.8 KiB
Specifying interrupt information for devices |
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============================================ |
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1) Interrupt client nodes |
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------------------------- |
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Nodes that describe devices which generate interrupts must contain an |
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"interrupts" property, an "interrupts-extended" property, or both. If both are |
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present, the latter should take precedence; the former may be provided simply |
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for compatibility with software that does not recognize the latter. These |
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properties contain a list of interrupt specifiers, one per output interrupt. The |
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format of the interrupt specifier is determined by the interrupt controller to |
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which the interrupts are routed; see section 2 below for details. |
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Example: |
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interrupt-parent = <&intc1>; |
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interrupts = <5 0>, <6 0>; |
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The "interrupt-parent" property is used to specify the controller to which |
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interrupts are routed and contains a single phandle referring to the interrupt |
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controller node. This property is inherited, so it may be specified in an |
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interrupt client node or in any of its parent nodes. Interrupts listed in the |
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"interrupts" property are always in reference to the node's interrupt parent. |
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The "interrupts-extended" property is a special form; useful when a node needs |
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to reference multiple interrupt parents or a different interrupt parent than |
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the inherited one. Each entry in this property contains both the parent phandle |
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and the interrupt specifier. |
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Example: |
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interrupts-extended = <&intc1 5 1>, <&intc2 1 0>; |
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2) Interrupt controller nodes |
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----------------------------- |
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A device is marked as an interrupt controller with the "interrupt-controller" |
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property. This is a empty, boolean property. An additional "#interrupt-cells" |
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property defines the number of cells needed to specify a single interrupt. |
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It is the responsibility of the interrupt controller's binding to define the |
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length and format of the interrupt specifier. The following two variants are |
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commonly used: |
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a) one cell |
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----------- |
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The #interrupt-cells property is set to 1 and the single cell defines the |
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index of the interrupt within the controller. |
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Example: |
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vic: intc@10140000 { |
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compatible = "arm,versatile-vic"; |
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interrupt-controller; |
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#interrupt-cells = <1>; |
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reg = <0x10140000 0x1000>; |
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}; |
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sic: intc@10003000 { |
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compatible = "arm,versatile-sic"; |
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interrupt-controller; |
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#interrupt-cells = <1>; |
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reg = <0x10003000 0x1000>; |
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interrupt-parent = <&vic>; |
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interrupts = <31>; /* Cascaded to vic */ |
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}; |
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b) two cells |
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------------ |
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The #interrupt-cells property is set to 2 and the first cell defines the |
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index of the interrupt within the controller, while the second cell is used |
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to specify any of the following flags: |
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- bits[3:0] trigger type and level flags |
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1 = low-to-high edge triggered |
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2 = high-to-low edge triggered |
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4 = active high level-sensitive |
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8 = active low level-sensitive |
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Example: |
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i2c@7000c000 { |
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gpioext: gpio-adnp@41 { |
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compatible = "ad,gpio-adnp"; |
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reg = <0x41>; |
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interrupt-parent = <&gpio>; |
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interrupts = <160 1>; |
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gpio-controller; |
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#gpio-cells = <1>; |
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interrupt-controller; |
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#interrupt-cells = <2>; |
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nr-gpios = <64>; |
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}; |
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sx8634@2b { |
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compatible = "smtc,sx8634"; |
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reg = <0x2b>; |
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interrupt-parent = <&gpioext>; |
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interrupts = <3 0x8>; |
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#address-cells = <1>; |
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#size-cells = <0>; |
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threshold = <0x40>; |
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sensitivity = <7>; |
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}; |
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}; |
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3) Interrupt wakeup parent |
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-------------------------- |
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Some interrupt controllers in a SoC, are always powered on and have a select |
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interrupts routed to them, so that they can wakeup the SoC from suspend. These |
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interrupt controllers do not fall into the category of a parent interrupt |
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controller and can be specified by the "wakeup-parent" property and contain a |
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single phandle referring to the wakeup capable interrupt controller. |
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Example: |
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wakeup-parent = <&pdc_intc>;
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