132 lines
3.7 KiB
Plaintext
132 lines
3.7 KiB
Plaintext
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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(NOTE: only this 'special form' is supported in U-Boot)
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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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Example of special form (supported by U-Boot):
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acpi_gpe: general-purpose-events {
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reg = <IOMAP_ACPI_BASE IOMAP_ACPI_SIZE>;
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compatible = "intel,acpi-gpe";
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interrupt-controller;
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#interrupt-cells = <2>;
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};
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tpm@50 {
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reg = <0x50>;
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compatible = "google,cr50";
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u-boot,i2c-offset-len = <0>;
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ready-gpio = <&gpio_n 28 GPIO_ACTIVE_LOW>;
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interrupts-extended = <&acpi_gpe 0x3c 0>;
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};
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