Re: Associate physical device with device name

[Jimmy Assarsson <extja@kvaser.com>]

On 2018-02-08 13:45, Marc Kleine-Budde wrote:
> On 01/26/2018 03:38 PM, Jimmy Assarsson wrote:
>> We would like to be able to associate physical (Kvaser) USB devices with
>> their device names (can0 etc.).
>> The interface's EAN (article number) combined with serial number, form a
>> unique identifier.
>>
>> It is not possible to do this from the USB descriptor. Since the serial
>> number is not provided in the USB descriptor. And the same PID is reused
>> for multiple EAN numbers. It is preferable with a solution that is
>> independent of interface type (USB etc.), since we may support other
>> devices in the future.
>>
>> This is somewhat similar to '"user id" for can usb adapters',
>> https://marc.info/?l=linux-can&m=146565019622100
>>
>> What is the preferable way of solving this kind of problem? Is sysfs
>> suitable?
> 
> Are your adaptors 100% idential? Then there is no way to tell them apart
> in software. However you should be possible to write a custom udev rule
> to rename the adapter depending on the physical USB-Port you are using.

No, they are not identical. The EAN and serial number is stored on the
device. Which makes a single device unique. It is possible to fetch
these from the device. And same applies to all Kvaser CAN interfaces,
regardless if they are connected via USB, PCI-express or ethernet.