Re: SocketCAN support for a Serial-CAN controller

[Oliver Hartkopp <socketcan@hartkopp.net>]

On 04/25/2016 09:26 AM, Rein Appeldoorn wrote:

> Thanks for the feedback. I think it is best we go for a PCI SJ1000
> controller then. Do you perhaps have any recommendations on this? I
> was thinking about the PEAK can pci controller:
> http://www.peak-system.com/PCAN-miniPCIe.285.0.html

I have some of them running in a Core i7 carpc setup and can confirm 
that they are working out of the box with Mainline Linux.

Best regards,
Oliver

>
> On Sat, Apr 23, 2016 at 3:54 PM, Oliver Hartkopp <socketcan@hartkopp.net> wrote:
>> Hello Rein,
>>
>> On 04/22/2016 01:17 PM, Rein Appeldoorn wrote:
>>
>>> Up until now, I've been working with SocketCAN via CANUSB adapters
>>> from Lawycel (http://www.can232.com/?page_id=16). However, now we
>>> received a new platform with another serial-can controller from
>>> axiomtek
>>> (http://www.axiomtek.com/Default.aspx?MenuId=Products&FunctionId=ProductView&ItemId=8270).
>>>
>>> I am able to communicate with the CAN controller via serial and
>>> receive CAN frames. However, using slcand to create a socketcan
>>> interface does not work. As I see here
>>> https://github.com/linux-can/can-utils/blob/master/slcand.c , the
>>> slcand program sends specific commands to the serial bus and then
>>> creates a bridge between the socket and serial. However, the commands
>>> are different for my CAN controller.
>>
>>
>> Yes. That's pretty bad to reinvent the wheel by creating 'just another' CAN
>> ASCII protocol :-(
>>
>>> Can somebody give me some pointers how to get SocketCAN to work with
>>> an arbitrary serial-can controller?
>>
>>
>> The slcan driver supports the standard SLCAN protocols as you know from
>> Lawicel:
>>
>> https://github.com/linux-can/can-misc/blob/master/docs/SLCAN-API.pdf
>>
>>> I'm am very new to these low level Linux things so I really would
>>> appreciate your help / corrections. Thanks in advance,
>>
>>
>> You would need to extend the slcan.c driver and the slcan tools from the
>> can-utils to cope with the Axiomtek protocol.
>>
>> Alternatively you can write a user space application that talks to the
>> Axiomtek device and send the CAN frames to a virtual CAN (e.g. vcan0) so
>> that you can use the can-utils on top of that virtual CAN.
>>
>> Just a different idea: As you obviously have a full-size mini PCI-Express
>> module - why don't you use a proper CAN PCIe interface with a PCI-connected
>> SJA1000 controller which is already supported by Linux?
>>
>> All this serial line encapsulation stuff does not support the really good
>> (configuration) things and error handling from SocketCAN.
>>
>> Regards,
>> Oliver
>>
>> ps. Maybe Axiomtek can also provide a SLCAN compatible firmware ...
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