CAN bus Linux driver

The current CAN bus driver uses SocketCAN API which is now the official CAN API for Linux. SocketCAN is based on the Linux socket. Further details can be found on the links at the bottom of this page.

Driver installation

 $ make linux26-menuconfig

Networking support  --->
    <M>   CAN bus subsystem support ---> 
        --- CAN bus subsystem support
        <M>   Raw CAN Protocol (raw access with CAN-ID filtering)
        <M>   Broadcast Manager CAN Protocol (with content filtering)
              CAN Device Drivers  --->
                  <M> Virtual Local CAN Interface (vcan)
                  <M> Microchip 251x series SPI CAN Controller

 $ make

• Reflash kernel and rootfs

Usage

• Load all the needed drivers:

modprobe can
modprobe candev
modprobe can-raw
modprobe mcp251x

Quick test

Once the driver installed, the CAN interface has to be started like a standard net interface

 # ifconfig can0 up

and can be stopped like that:

 # ifconfig can0 down

The socketCAN version can be retrieved like that:

 # cat /proc/net/can/version

The socketCAN statistics can be retrieved like that:

 # cat /proc/net/can/stats

The default baud rate is 250kbauds

Userspace tools

• Several tools are provided by socketCAN:
  • candump: dump traffic on a CAN network
  • cansend: simple command line tool to send CAN-frames via CAN_RAW sockets
  • cangen: CAN frames generator for testing purpose
  • canplayer: send CAN frames from a file to a CAN interface

• These tools can be compiled and installed on the target by means of the Buildroot menuconfig:

$ make menuconfig

Package Selection for the target  --->
    Networking  --->
        [*]   Socket CAN
        [*]     install test tools

$ make

then, reflash your rootfs.

Links

• http://developer.berlios.de/projects/socketcan/ (CAN Linux Driver)
• http://ww1.microchip.com/downloads/en/DeviceDoc/21801e.pdf (MCP2515 datasheet)
• http://www.kvaser.com/can/protocol/index.htm (CAN introduction)