如何使用Python通过Product ID和Vendor ID查找设备所连接的端口（如/dev/ttyACM0等）

Alright, let's figure out how to locate the serial port path (like /dev/ttyACM0) for a device using its Vendor ID (VID) and Product ID (PID) with Python. I'll walk you through two solid approaches—one using a handy library, and another that works without any extra installs.

Method 1: Using pyudev (Recommended) #

The pyudev library is built specifically for interacting with Linux udev devices, so it's clean and reliable for this task.

First, install the library:

pip install pyudev

Then use this code snippet to find your device's port:

import pyudev

def find_device_port(vid, pid):
    # Convert VID/PID to lowercase hex strings (handles both int and string inputs)
    vid_str = f"{vid:04x}" if isinstance(vid, int) else vid.lower()
    pid_str = f"{pid:04x}" if isinstance(pid, int) else pid.lower()

    context = pyudev.Context()
    # Iterate over all tty devices
    for device in context.list_devices(subsystem='tty'):
        # Find the parent USB device (where VID/PID are stored)
        usb_parent = device.find_parent('usb', 'usb_device')
        if usb_parent:
            # Match the VID/PID
            if (usb_parent.get('ID_VENDOR_ID') == vid_str 
                and usb_parent.get('ID_MODEL_ID') == pid_str):
                return device.device_node  # Returns path like /dev/ttyACM0
    return None

# Example usage: Replace with your device's VID and PID
target_vid = 0x0483  # Can also pass as string "0483"
target_pid = 0x5740  # Or string "5740"
port = find_device_port(target_vid, target_pid)

if port:
    print(f"Found your device at: {port}")
else:
    print("Device not connected, or no matching port found.")

Method 2: Parsing sysfs (No Third-Party Libraries) #

If you don't want to install extra packages, you can directly read from the Linux sysfs filesystem, which exposes device metadata.

import os

def find_device_port(vid, pid):
    vid_str = f"{vid:04x}" if isinstance(vid, int) else vid.lower()
    pid_str = f"{pid:04x}" if isinstance(pid, int) else pid.lower()
    tty_class_path = '/sys/class/tty'

    for tty_device in os.listdir(tty_class_path):
        # Follow the symlink to the device's actual path
        device_symlink = os.path.join(tty_class_path, tty_device, 'device')
        if not os.path.exists(device_symlink):
            continue
        
        real_device_path = os.path.realpath(device_symlink)
        # Skip non-USB devices
        if 'usb' not in real_device_path:
            continue
        
        # Read VID and PID from sysfs files
        vid_file = os.path.join(real_device_path, 'idVendor')
        pid_file = os.path.join(real_device_path, 'idProduct')
        if not os.path.exists(vid_file) or not os.path.exists(pid_file):
            continue
        
        with open(vid_file, 'r') as f:
            current_vid = f.read().strip()
        with open(pid_file, 'r') as f:
            current_pid = f.read().strip()
        
        if current_vid == vid_str and current_pid == pid_str:
            return f"/dev/{tty_device}"
    return None

# Example usage
target_vid = 0x1a86  # CH340 VID
target_pid = 0x7523  # CH340 PID
port = find_device_port(target_vid, target_pid)
print(port if port else "Device not found.")

Important Notes #

• Permissions: Ensure your user has access to serial ports. On most Linux systems, add yourself to the dialout group with:

  sudo usermod -aG dialout $USER
  

  Log out and back in for this change to take effect.
• Duplicate Devices: If multiple devices share the same VID/PID, both methods will return the first matching port. To distinguish them, you can add checks for the device's serial number (look for ID_SERIAL in pyudev, or the serial file in sysfs).
• VID/PID Format: You can pass VID/PID as integers (e.g., 0x1234) or lowercase hex strings (e.g., "1234").

内容的提问来源于stack exchange，提问作者mekanizm