树莓派设备树覆盖（dtb overlay）

最新推荐文章于 2024-10-28 00:01:09 发布

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最新推荐文章于 2024-10-28 00:01:09 发布

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分类专栏：嵌入式文章标签：设备树

本文链接：https://blog.youkuaiyun.com/abc4764/article/details/112759220

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dtb overlay测试

原始的设备树结构：

pi@raspberrypi:~ $ ls /proc/device-tree
'#address-cells'   compatible           leds            reserved-memory   __symbols__
 aliases           cpus                 memory@0        scb               system
 arm-pmu           emmc2bus             memreserve      sd_io_1v8_reg     thermal-zones
 axi               fixedregulator_3v3   model           sd_vcc_reg        timer
 chosen            fixedregulator_5v0   name            serial-number     v3dbus
 clk-108M          gpu                  __overrides__  '#size-cells'
 clocks            interrupt-parent     phy             soc

测试节点设备树：

/dts-v1/;
/plugin/;

/ {
  fragment@0 {
    target-path = "/";
    __overlay__ {
      dt_overlay_test {
        compatible = "led_type_a";
      };
    };
  };
};

将上述设备树编译为dtbo后，进行如下操作：

pi@raspberrypi:/sys/kernel/config/device-tree/overlays $ sudo mkdir test
pi@raspberrypi:/sys/kernel/config/device-tree/overlays $ ls
test
pi@raspberrypi:/sys/kernel/config/device-tree/overlays $ cd test/
pi@raspberrypi:/sys/kernel/config/device-tree/overlays/test $ ls
dtbo  path  status
pi@raspberrypi:/sys/kernel/config/device-tree/overlays/test $ sudo cp ~/work/dt_overlay_test.dtbo ./dtbo
pi@raspberrypi:/sys/kernel/config/device-tree/overlays/test $ cat status
applied

添加测试节点后：

pi@raspberrypi:~/work $ ls /proc/device-tree/                                                 '#address-cells'   compatible           interrupt-parent   phy               soc
 aliases           cpus                 leds               reserved-memory   __symbols__
 arm-pmu           dt_overlay_test      memory@0           scb               system
 axi               emmc2bus             memreserve         sd_io_1v8_reg     thermal-zones
 chosen            fixedregulator_3v3   model              sd_vcc_reg        timer
 clk-108M          fixedregulator_5v0   name               serial-number     v3dbus
 clocks            gpu                  __overrides__     '#size-cells'