using slcand to use socketCAN with chardev interface

[0xfafa]

Hello,

I have the following USB device: PCAN-USB Pro FD (01h PCB02h) fw v3.2.0 bl v2.1.0 connected to a PI4. The PI4 is running balena's IOT software which contains a YOCTO-based Host OS and our application container. The peak drivers were thus not part of the host OS but I managed to build them by finding appropriate kernel headers, etc. When I build in chardev mode, I see there are /dev/pcanusb32 and /dev/pcanusb33 devices, and using pcanfdtst I can read FD frames. However, for compatibility with the rest of our software stack I would like to use the socketCAN interface. For other USB devices I would use the slcand utility to map the serial device to a virtual can network-based device which then shows up as can0 in ip link. However, when I run this I get the following error in dmesg.

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[232628.396224] pcan: __pcan_ioctl(cmd=21505): unsupported cmd (dir=0 type=84 nr=1 size=0)

There is another forum message viewtopic.php?f=59&t=2491&start=10 with same error for a PCI device but I was unable to find a resolution.

My other option is to build the peak driver to use the network interface. However, when I try to load it, it fails because it depends on driver can-dev which is also missing in our build (though can and can-raw are available) and I have not been able to find the source for that.

Can you suggest how to address either the slcand problem or the can-dev issue?

[M.Heidemann]

Hello,

You cannot use SocketCAN with the chardev driver variant, it only supports
PEAKs Linux APIs. You'll need to use the NetDev variant, here's how you do that:

If you want to use SocketCAN, uninstall the current driver (from the peak-driver directory):

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$ sudo make uninstall

Clean up build environment

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make clean

Build driver as NetDev:

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$ sudo make NET=NETDEV_SUPPORT

intall the driver:

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$ sudo make install

Load the driver:

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 $ sudo modprobe pcan 

You PCAN-USB should now show up as a net device, like
can0, can1, can2, etc.

You can now use it with SocketCAN.

Best Regards

Marvin

[0xfafa]

Thank you Marvin,

Using the balenaOS it's a bit more complicated because the drivers are on the host OS and not all are available to the application container but eventually got it working using the NetDev variant.

[M.Heidemann]

Hello,

Glad to hear that you were able to resolve this.

Best Regards

Marvin