How to control GPIO under Linux

Under Linux, you can use 4 methods to control GPIO: "Sysfs interface", "GPIO library", "device tree" and "direct access register": 1. Through the files in the /sys/class/gpio directory , you can access and control GPIO pins; 2. The open source GPIO library can simplify the control of GPIO, making it more convenient to program and control GPIO on Linux systems; 3. You can edit the device tree file, define the attributes and functions of GPIO, and configure it in the system Load device tree on startup and so on.

Under Linux, you can use the following methods to control GPIO (General Purpose Input and Output):

1. Sysfs interface : Sysfs is a file system interface provided by the Linux kernel for interacting with device drivers. GPIO pins can be accessed and controlled through files in the /sys/class/gpio directory. You can use shell commands or a programming language (such as Python) to read or write these files to control the status of the GPIO.

2. GPIO library: There are some open source GPIO libraries that simplify GPIO control. For example, libraries such as WiringPi, RPi.GPIO and libgpiod provide functions and interfaces, making it more convenient to programmatically control GPIO on Linux systems. You can choose the appropriate library according to your needs and install and use it according to its documentation.

3. Device Tree: For some embedded systems, GPIO mapping and configuration information are usually stored in the device tree. You can edit the device tree file, define the properties and functions of the GPIO, and load the device tree when the system starts so that the GPIO can be correctly initialized and used.

4. Direct access to registers: On some specific embedded platforms, you can directly access GPIO-related physical registers for control. This requires a deeper understanding of the hardware and underlying system, so it needs to be done with caution.

It should be noted that GPIO control requires privileged permissions (usually root or a user with corresponding permissions) to execute. During programming, you may need to use appropriate permissions or configurations to ensure access and control of the GPIO.

Please remember that when operating GPIO, be careful to avoid incorrect operations to avoid damage or adverse effects. Before using GPIO, it is recommended to understand the hardware specifications and related documents, and follow the correct method to control and operate.

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