DESK-MX6-L/Pheripherals/CAN

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History
Issue Date Notes

2021/07/16

First DESK-MX6-L release

2022/03/03

DESK-MX6-L 3.0.0 release
2023/04/11 DESK-MX6-L 4.0.0 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]

...
...
[    4.455222] can: controller area network core
[    4.464472] can: raw protocol
[    4.467614] can: broadcast manager protocol
[    4.471816] 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
[  839.886499] 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 7ff#0001020304050607
  can0  7FF   [8]  00 01 02 03 04 05 06 07
  can0  7FF   [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