1 Scope of Document
This document describes how to write udev script, when enum usb device maybe produces several interfaces(/dev/ttyUSB*),
if we want to compatible serveral usb modules, udev script is very useful.when module insert or remove, spec udev script will
be called.example: this module have four port, we can enumerated to specific devices(/dev/ttyfdti1,/dev/ttyftdi1,/dev/ttyftdi2,/dev/ttyftdi3).
#add for ftdi usb-serial
ACTION=="add",KERNELS=="1-1.4:1.0",SUBSYSTEMS=="usb",DRIVERS=="ftdi_sio",SYMLINK+="ttyftdi0"
ACTION=="add",KERNELS=="1-1.4:1.1",SUBSYSTEMS=="usb",DRIVERS=="ftdi_sio",SYMLINK+="ttyftdi1"
ACTION=="add",KERNELS=="1-1.4:1.2",SUBSYSTEMS=="usb",DRIVERS=="ftdi_sio",SYMLINK+="ttyftdi2"
ACTION=="add",KERNELS=="1-1.4:1.3",SUBSYSTEMS=="usb",DRIVERS=="ftdi_sio",SYMLINK+="ttyftdi3"
#remove for ftdi usb-serial
ACTION=="remove",KERNELS=="1-1.4:1.0",SUBSYSTEMS=="usb",DRIVERS=="ftdi_sio",SYMLINK+="ttyftdi0"
ACTION=="remove",KERNELS=="1-1.4:1.1",SUBSYSTEMS=="usb",DRIVERS=="ftdi_sio",SYMLINK+="ttyftdi1"
ACTION=="remove",KERNELS=="1-1.4:1.2",SUBSYSTEMS=="usb",DRIVERS=="ftdi_sio",SYMLINK+="ttyftdi2"
ACTION=="remove",KERNELS=="1-1.4:1.3",SUBSYSTEMS=="usb",DRIVERS=="ftdi_sio",SYMLINK+="ttyftdi3"
2 Requiremen
2.1 Function Requirement
Custom private udev rules,compatible different hardware module.
2.2 Performance Requirement
NA
3 Hardware Overview
NA
4 Functional Description
4.1 Functional Block Diagram
NA
5 Porting
5.1 System configure
Reference: https://wiki.archlinux.org/index.php/Udev_(简体中文)
https://mirrors.edge.kernel.org/pub/linux/utils/kernel/hotplug/udev/udev.html
example1:
when ec20 module be enumed, it can emum five device interfaces, /dev/tty20ec0,
/dev/tty20ec1,/dev/tty4g,/dev/tty20ec3,/dev/tty20ec4.attention to when enum /dev/tty4g interface, it will run /bin/ifup mobile script to diag-up.
If all internet access modules, its diag port was enumed to /dev/tty4g, we can compible all internet access modules in openwrt rootfs.
# add for ec20
ACTION=="add", ATTRS{modalias}=="usb:v2C7Cp0125d0318dcEFdsc02dp01icFFiscFFipFFin00", ATTRS{bInterfaceNumber}=="00", SYMLINK="tty20ec0"
ACTION=="add", ATTRS{modalias}=="usb:v2C7Cp0125d0318dcEFdsc02dp01icFFisc00ip00in01", ATTRS{bInterfaceNumber}=="01", SYMLINK="tty20ec1"
ACTION=="add", ATTRS{modalias}=="usb:v2C7Cp0125d0318dcEFdsc02dp01icFFisc00ip00in02", ATTRS{bInterfaceNumber}=="02", SYMLINK="tty4g",RUN="/sbin/ifup mobile"
ACTION=="add", ATTRS{modalias}=="usb:v2C7Cp0125d0318dcEFdsc02dp01icFFisc00ip00in03", ATTRS{bInterfaceNumber}=="03", SYMLINK="tty20ec3"
ACTION=="add", ATTRS{modalias}=="usb:v2C7Cp0125d0318dcEFdsc02dp01icFFiscFFipFFin04", ATTRS{bInterfaceNumber}=="04", SYMLINK="tty20ec4"
# remove for ec20
ACTION=="remove", ATTRS{modalias}=="usb:v2C7Cp0125d0318dcEFdsc02dp01icFFiscFFipFFin00", ATTRS{bInterfaceNumber}=="00", SYMLINK="tty20ec0"
ACTION=="remove", ATTRS{modalias}=="usb:v2C7Cp0125d0318dcEFdsc02dp01icFFisc00ip00in01", ATTRS{bInterfaceNumber}=="01", SYMLINK="tty20ec1"
ACTION=="remove", ATTRS{modalias}=="usb:v2C7Cp0125d0318dcEFdsc02dp01icFFisc00ip00in02", ATTRS{bInterfaceNumber}=="02", SYMLINK="tty4g",RUN="/sbin/ifdown mobile"
ACTION=="remove", ATTRS{modalias}=="usb:v2C7Cp0125d0318dcEFdsc02dp01icFFisc00ip00in03", ATTRS{bInterfaceNumber}=="03", SYMLINK="tty20ec3"
ACTION=="remove", ATTRS{modalias}=="usb:v2C7Cp0125d0318dcEFdsc02dp01icFFiscFFipFFin04", ATTRS{bInterfaceNumber}=="04", SYMLINK="tty20ec4"
Example2:
if you have two usb-serial modules, and you
want to distinguish between them, you can reference follow udev script methon:
#add for ftdi usb-serial
ACTION=="add",KERNELS=="1-1.4:1.0",SUBSYSTEMS=="usb",DRIVERS=="ftdi_sio",SYMLINK+="ttyftdi0"
ACTION=="add",KERNELS=="1-1.4:1.1",SUBSYSTEMS=="usb",DRIVERS=="ftdi_sio",SYMLINK+="ttyftdi1"
ACTION=="add",KERNELS=="1-1.4:1.2",SUBSYSTEMS=="usb",DRIVERS=="ftdi_sio",SYMLINK+="ttyftdi2"
ACTION=="add",KERNELS=="1-1.4:1.3",SUBSYSTEMS=="usb",DRIVERS=="ftdi_sio",SYMLINK+="ttyftdi3"
#remove for ftdi usb-serial
ACTION=="remove",KERNELS=="1-1.4:1.0",SUBSYSTEMS=="usb",DRIVERS=="ftdi_sio",SYMLINK+="ttyftdi0"
ACTION=="remove",KERNELS=="1-1.4:1.1",SUBSYSTEMS=="usb",DRIVERS=="ftdi_sio",SYMLINK+="ttyftdi1"
ACTION=="remove",KERNELS=="1-1.4:1.2",SUBSYSTEMS=="usb",DRIVERS=="ftdi_sio",SYMLINK+="ttyftdi2"
ACTION=="remove",KERNELS=="1-1.4:1.3",SUBSYSTEMS=="usb",DRIVERS=="ftdi_sio",SYMLINK+="ttyftdi3"