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udev/udevadm - dynamic dev symbolic link and proper access rights

Introduction

Thanks to the literature research of M.Traxler and the inventors of udev/udevadm it is possible to assign automatically (fixed) symbolic links for USB devices connected to the system pointing the current /dev entry point.

How To

Prerequisites

you have to have admin rights.

How to

• edit/create /etc/udev/rules.d/99-serial-permissions.rules
  
  • add the follwing line for general includes
    SUBSYSTEMS=="usb", ATTRS{idVendor}=="0403", SYMLINK+="$env{ID_SERIAL}", GROUP="users", MODE="0666"
    creates for every connected device of vendor id 0403 a symbolic link /dev/ to the connected device
    
  • for special devices those lines can be added in addition
    SUBSYSTEMS=="usb", ATTRS{idVendor}=="0403", ENV{ID_SERIAL}=="FTDI_FT232R_USB_UART_A100dQ2B", SYMLINK+="hadcon2", GROUP="users", MODE="0666"
SUBSYSTEMS=="usb", ATTRS{idVendor}=="0403", ENV{ID_SERIAL}=="FTDI_FT232R_USB_UART_A600801P", SYMLINK+="olimex",  GROUP="users", MODE="0666"
    
• to find out the IDs of connected systems
  udevadm info --export-db| grep FTDI| grep ID_SERIAL
  
  
• Finally reload rules and trigger a reconnect:
  

  openSuse

  udevadm control --reload-rules
udevadm trigger

  debian

  udevadm control --reload_rules
udevadm trigger

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-- PeterZumbruch - 02 Apr 2013
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