DESK-MX6-L/Pheripherals/CAN

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History
ID# Issue Date Notes

14105

16/07/2021 First DESK release

16995

03/03/2022 DESK 3.0.0 release


Peripheral CAN[edit | edit source]

Device tree configuration[edit | edit source]

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 peripheral[edit | edit source]

Linux messages at boot time[edit | edit source]

...
...
[    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 status[edit | edit source]

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-utils[edit | edit source]

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 information[edit | edit source]

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