GPIO 并不总是需要在 Linux 内核设备树中配置。是否需要在设备树中配置 GPIO 取决于系统中使用和访问 GPIO 的方式。
以下是一些可能需要也可能不需要在设备树中配置 GPIO 的情况：
1. 直接访问 GPIO： 用户空间应用程序使用 sysfs 或字符设备文件等接口直接访问的 GPIO 通常不需要在设备树中配置。这些 GPIO 可由用户空间程序动态导出和控制，无需内核参与。
2. 设备驱动程序使用的 GPIO： 如果 GPIO 被设备驱动程序用于控制硬件或与硬件通信，通常会在设备树中进行配置。这样可以确保内核正确初始化 GPIO，并使设备驱动程序可以访问它。
3. 平台特定的 GPIO：有些 GPIO 是硬件平台特定的，用于电源管理、系统复位或电路板特定功能等功能。这些 GPIO 通常在设备树中配置，以确保内核正确初始化和使用。
4. 动态 GPIO 分配： 在某些情况下，GPIO 可在运行时由设备驱动程序动态分配或控制。在这种情况下，可能不需要在设备树中进行显式配置。
总之，是否必须在 Linux 内核设备树中配置 GPIO 取决于其用途和在系统中的访问方式。设备驱动程序或平台特定功能使用的 GPIO 通常要在设备树中配置，以确保内核正确初始化和使用。不过，用户空间应用程序直接访问的 GPIO 可能不需要在设备树中配置。
| GPIOs are not always required to be configured in the Linux kernel device tree. Whether a GPIO needs to be configured in the device tree depends on how it's being used and accessed within the system. Here are some scenarios where GPIOs may or may not need to be configured in the device tree: 1. Directly Accessed GPIOs: GPIOs that are directly accessed by user-space applications using interfaces like sysfs or character device files typically do not need to be configured in the device tree. These GPIOs can be dynamically exported and controlled by user-space programs without kernel involvement. 2. GPIOs Used by Device Drivers: If a GPIO is used by a device driver to control or communicate with hardware, it's usually configured in the device tree. This ensures that the kernel initializes the GPIO properly and makes it accessible to the device driver. 3. Platform-Specific GPIOs: Some GPIOs are specific to the hardware platform and are used for functions such as power management, system reset, or board-specific features. These GPIOs are typically configured in the device tree to ensure proper initialization and usage by the kernel. 4. Dynamic GPIO Allocation: In certain cases, GPIOs may be dynamically allocated or controlled by device drivers at runtime. In such scenarios, they may not need to be explicitly configured in the device tree. In summary, whether a GPIO must be configured in the Linux kernel device tree depends on its usage and how it's accessed within the system. GPIOs used by device drivers or for platform-specific functions are usually configured in the device tree to ensure proper initialization and usage by the kernel. However, GPIOs accessed directly by user-space applications may not need to be configured in the device tree. |
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