Absolutely, you can establish a communication link between your embedded Linux application and laptop-based configuration app using a USB-to-USB cable—let’s break down the best options tailored to your existing LAN-based workflow:

1. USB Virtual Serial Port (Plug-and-Play Simplicity) #

• Grab a USB-to-USB serial bridge cable (not a regular USB male-to-male cable—those can short out your devices!). Look for cables with chips like PL2303 or FT232, which have widespread driver support.
• On your industrial Linux machine: Most embedded kernels come with the usbserial driver pre-built. When you plug in the cable, you’ll see a new serial device node like /dev/ttyUSB0 show up.
• On your laptop: Windows/macOS will auto-install the necessary drivers, creating a COM port (Windows) or /dev/tty.usbserial-* (macOS).
• Adapting your apps: If your current setup uses TCP/UDP, use a tool like ser2net on the Linux side to map the serial port to a TCP socket. Your configuration app can then connect to this virtual TCP port almost without any code changes.

2. USB Virtual Ethernet (Closest to Your Existing LAN Workflow) #

• Use a USB-to-USB Ethernet bridge cable—this is essentially two USB-to-Ethernet adapters integrated into one cable, creating a private wired network between the two devices.
• On your industrial Linux machine: If your kernel supports the usbnet driver, a new network interface (e.g., eth1) will appear. Assign it a static IP (like 192.168.4.10).
• On your laptop: Your OS will recognize it as a standard Ethernet adapter. Set its IP to the same subnet (e.g., 192.168.4.20).
• Adapting your apps: This mimics a tiny private LAN, so your configuration app can use its existing LAN discovery logic (like MDNS broadcasts or IP scanning) to find the embedded app. This is the lowest-effort option for your current setup—no major code changes needed.

3. Custom USB CDC Gadget (For Deep Customization) #

• If your industrial Linux device supports USB OTG and gadget mode (common on most embedded SoCs), you can configure it to act as a USB CDC (Communication Device Class) device, emulating either a serial port or Ethernet adapter.
• Linux setup: Load the g_cdc kernel module, then configure the virtual network interface with a static IP. No special cable is needed—just a standard USB male-to-male cable (confirm your device supports OTG first!).
• Caveat: This requires some familiarity with embedded Linux USB gadget configuration, but it’s great if you want to avoid buying specialized cables.

• Never use a regular USB male-to-male charging cable—these lack the bridge chip and can short power lines, damaging your devices.
• Verify your industrial Linux kernel has the required drivers: Check for usbserial (under /lib/modules/$(uname -r)/kernel/drivers/usb/serial) or usbnet (under /lib/modules/$(uname -r)/kernel/drivers/net/usb) modules. If missing, you’ll need to recompile the kernel with these drivers enabled.
• If using virtual Ethernet, temporarily disable firewalls on both devices (or add rules to allow traffic on your app’s ports) to rule out connection blocks.

内容的提问来源于stack exchange，提问作者Conor McCarthy