CAN Overlay missing for BeagleBone AI-64

General Discussion
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Hello @benedict.hewson

Thank you for the reply. I am able to setup CAN overlay. Steps I have followed:

  1. Git clone BeagleBoard Device Trees

$ git clone https://git.beagleboard.org/beagleboard/BeagleBoard-DeviceTrees.git

$ cd BeagleBoard-DeviceTrees
  1. Edit k3-j721e-beagleboneai64-bone-buses.dtsi in src/arm64 and add the following lines at the end

bone_can_0: &mcu_mcan0 {
                 pinctrl-names = "default";
                 pinctrl-0 = <
                              &P9_19_can_pin /* mcan0_rxd */
                              &P9_20_can_pin /* mcan0_txd */
                             >;
                 symlink = "bone/can/1";
                 status = "disabled";
};
  1. Create new CAN0 overlay file BONE-CAN0.dts with the following content in src/arm64/overlays/ 
/*
* Copyright (C) 2022 BeagleBoard.org - https://beagleboard.org/
*
* https://elinux.org/Beagleboard:BeagleBone_cape_interface_spec#CAN
*/

/dts-v1/;
/plugin/;

/*
* Helper to show loaded overlays under: /proc/device-tree/chosen/overlays/
*/

&{/chosen} {
        overlays {
                  BONE-CAN0.kernel = __TIMESTAMP__;
                 };
           };

&bone_can_0 {
        status = "okay";
            };
  1. Compile and install from parent directory BeagleBoard-DeviceTrees 

$ make
$ sudo make install
  1. Reboot

$ sudo reboot
  1. Test if CAN interfae is loaded

$ sudo beagle-version | grep UBOOT

UBOOT: Booted Device-Tree:[k3-j721e-beagleboneai64.dts]
UBOOT: Loaded Overlay:[BONE-CAN0.kernel]
  1. Check for CAN interface in ip link

$ ip link

can0: <NOARP,ECHO> mtu 16 qdisc noop state DOWN mode DEFAULT group default qlen 10
    link/can

It shows can0 is DOWN. To make it available, run:


$ sudo ip link set can0 up type can bitrate 1000000
$ ip link

can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UP mode DEFAULT group default qlen 10
    link/can
  1. Increase txqueulen 

$ sudo ifconfig can0 txqueuelen 100

After following these steps I am able to send TX messges from terminal but candump shows no output. When I do

$ ip -det link show can0
3: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
    link/can  promiscuity 0 minmtu 0 maxmtu 0 
    can state ERROR-ACTIVE (berr-counter tx 0 rx 0) restart-ms 0 
	  bitrate 1000000 sample-point 0.750 
	  tq 12 prop-seg 29 phase-seg1 30 phase-seg2 20 sjw 1
	  m_can: tseg1 2..256 tseg2 2..128 sjw 1..128 brp 1..512 brp-inc 1
	  m_can: dtseg1 1..32 dtseg2 1..16 dsjw 1..16 dbrp 1..32 dbrp-inc 1
	  clock 80000000 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535

It shows can state ERROR-ACTIVE

What could be the reason? I hope you help.

Thank you

Best
Shubham

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