#interrupt-cells 是 2 但 interrupts 是一个三元组

Question

我正在查看 Beagle Bone Black 的设备树，并从

am57xx-beagle-x15.dts

开始。向下钻取

dra7.dtsi

我发现

gpio1

：

gpio1: gpio@4ae10000 {
            compatible = "ti,omap4-gpio";
            reg = <0x4ae10000 0x200>;
            interrupts = <GIC_SPI 24 IRQ_TYPE_LEVEL_HIGH>;
            ti,hwmods = "gpio1";
            gpio-controller;
            #gpio-cells = <2>;
            interrupt-controller;
            #interrupt-cells = <2>;
        };

我读过

#interrupt-cells

给出了

interrupts

列表中的项目中预期的 u32 或单元格的数量。但是当我看

interrupts

时，我看到一个三元组：

<GIC_SPI 24 IRQ_TYPE_LEVEL_HIGH>

。很想知道，为什么这包含 3 个单元格而不是 2 个？

Answer 1

这是一个很晚的答案，但请添加一个以便有人可以获得帮助。
我无法从我当前的 linux 5.15 源代码中找到确切的 dts 文件。但是节点的中断父节点应该需要 3 个单元格作为中断属性。对于 gic，通常它需要 3 个值——{中断类型、中断号、标志}。它在gic的设备绑定文档中（Documentation/devicetree/bindings/interrupt-controller/arm,gic.yaml in linux 5.15）

  "#interrupt-cells":
    const: 3
    description: |
      The 1st cell is the interrupt type; 0 for SPI interrupts, 1 for PPI
      interrupts.

      The 2nd cell contains the interrupt number for the interrupt type.
      SPI interrupts are in the range [0-987].  PPI interrupts are in the
      range [0-15].

      The 3rd cell is the flags, encoded as follows:
        bits[3:0] trigger type and level flags.
          1 = low-to-high edge triggered
          2 = high-to-low edge triggered (invalid for SPIs)
          4 = active high level-sensitive
          8 = active low level-sensitive (invalid for SPIs).
        bits[15:8] PPI interrupt cpu mask.  Each bit corresponds to each of
        the 8 possible cpus attached to the GIC.  A bit set to '1' indicated
        the interrupt is wired to that CPU.  Only valid for PPI interrupts.
        Also note that the configurability of PPI interrupts is IMPLEMENTATION
        DEFINED and as such not guaranteed to be present (most SoC available
        in 2014 seem to ignore the setting of this flag and use the hardware
        default value).

ADD (2023.5.3) :
gpio 节点本身是一种中断控制器，因此具有“中断控制器”属性。 gpio 节点中的“#interrupt-cells = <2>”说明了如何为其“中断生成”子设备指定中断输出。
这是从 Documentation/devicetree/bindings/gpio/gpio-zynq.txt of linux-5.10.00.

- interrupt-controller  : Marks the device node as an interrupt controller.
- #interrupt-cells  : Should be 2.  The first cell is the GPIO number.
              The second cell bits[3:0] is used to specify 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.