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025543554c
At present driver model supports the IRQ uclass but there is no way to request a particular interrupt for a driver. Add a mechanism, similar to clock and reset, to read the interrupts required by a device from the device tree and to request those interrupts. U-Boot itself does not have interrupt-driven handlers, so just provide a means to read and clear an interrupt. This can be useful to handle peripherals which must use an interrupt to determine when data is available, for example. Bring over the basic binding file as well, from Linux v5.4. Note that the older binding is not supported in U-Boot; the newer 'special form' must be used. Add a simple test of the new functionality. Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
131 lines
3.7 KiB
Text
131 lines
3.7 KiB
Text
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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