DESK-MX6UL-L/Pheripherals/CAN

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Work in progress


History
Version Issue Date Notes
1.0.0 Apr 2021 First DESK 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 ULite SOM:

From imx6ul-lynx-som0013-cb00XX.dts:

&can1 {
    pinctrl-names = "default";
    pinctrl-0 = <&pinctrl_flexcan1>;
    status = "okay";
};

From imx6ul-lynx-som0013.dtsi:

&iomuxc {
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_hog_gpios>;

        imx6ul-lynx {
...
...
            pinctrl_flexcan1: flexcan1grp{
                    fsl,pins = <
                            MX6UL_PAD_LCD_DATA09__FLEXCAN1_RX       0x1b020
                            MX6UL_PAD_LCD_DATA08__FLEXCAN1_TX       0x1b020
                    >;
            };
};

Accessing the peripheral[edit | edit source]

Linux messages at boot time[edit | edit source]

...
...
[    2.717142] flexcan 2090000.flexcan: 2090000.flexcan supply xceiver not found, using dummy regulator
[    2.728107] flexcan 2090000.flexcan: device registered (reg_base=a099c000, irq=24)
...
...
[    5.067979] can: controller area network core (rev 20170425 abi 9)
[    5.079006] can: raw protocol (rev 20170425)
[    5.083391] can: broadcast manager protocol (rev 20170425 t)
[    5.089108] can: netlink gateway (rev 20170425) max_hops=1

Enable the interface and check status[edit | edit source]

root@desk-mx6ul-axelulite:~# ip link set can0 type can bitrate 500000
root@desk-mx6ul-axelulite:~# ifconfig can0 up
root@desk-mx6ul-axelulite:~# ifconfig can0
can0      Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
          UP RUNNING NOARP  MTU:16  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:10
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
          Interrupt:24

root@desk-mx6ul-axelulite:~#

Usage with can-utils[edit | edit source]

TBD: reference verso eventuali informazioni sul web

root@desk-mx6ul-axelulite:~# ip link set can0 type can bitrate 500000 triple-sampling on
root@desk-mx6ul-axelulite:~# ifconfig can0 up
root@desk-mx6ul-axelulite:~# cansend can0 128#1122334455667788
root@desk-mx6ul-axelulite:~# candump can0
  can0  128   [8]  11 22 33 44 55 66 77 88
root@desk-mx6ul-axelulite:~# 

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.txt