DESK-MX6-L/Peripherals/CAN

History
Version	Issue Date	Notes
1.0.0	Oct 2020	First DESK release
3.0.0	Feb 2022	3.0.0 DESK release

Contents

Peripheral CANEdit

Device tree configurationEdit

Here below an example of device tree configuration used on standard DAVE's kit for the AXEL Lite SOM:

From imx6qdl-sbcx-revb-common.dtsi :

&can1 {
    pinctrl-names = "default";
    pinctrl-0 = <&pinctrl_flexcan1_axel>;
    status = "okay";
};

From imx6qdl-axelcommon.dtsi:

    can1 {
        pinctrl_flexcan1_axel: flexcan1axelgrp-1 {
            fsl,pins = <
                MX6QDL_PAD_GPIO_7__FLEXCAN1_TX 0x80000000
                MX6QDL_PAD_GPIO_8__FLEXCAN1_RX 0x80000000
            >;
        };
    };

Accessing the peripheralEdit

Linux messages at boot timeEdit

...
...
[    5.119440] can: controller area network core
[    5.128422] can: raw protocol
[    5.131399] can: broadcast manager protocol
[    5.135663] can: netlink gateway - max_hops=1
...
...

Enable the interface and check statusEdit

root@desk-mx6:~# ip link set can0 type can bitrate 500000
root@desk-mx6:~# ifconfig can0 up
[ 4184.530382] IPv6: ADDRCONF(NETDEV_CHANGE): can0: link becomes ready
root@desk-mx6:~# ifconfig can0
can0: flags=193<UP,RUNNING,NOARP>  mtu 16
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 10  (UNSPEC)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 39

Usage with can-utilsEdit

root@desk-mx6:~# ip link set can0 type can bitrate 500000 triple-sampling on loopback on                                                                                                                           
root@desk-mx6:~# ifconfig can0 up                                                                                                                                                                          
root@desk-mx6:~# candump can0 &                                                                                                                                                                          
[1] 321
interface = can0, family = 29, type = 3, proto = 1
root@desk-mx6:~# cansend can0 -i 0x7ff 00 01 02 03 04 05 06 07                                                                                                                                           
interface = can0, family = 29, type = 3, proto = 1
<0x7ff> [8] 00 01 02 03 04 05 06 07 
<0x7ff> [8] 00 01 02 03 04 05 06 07

Additional informationEdit

Each CAN port appears like a networking interface in the form canX where X is the port number.

Information about programming the CAN socket interface is given in the kernel tree under Documentation/networking/can.rst

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