From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jimmy Assarsson Subject: Re: Associate physical device with device name Date: Thu, 8 Feb 2018 14:04:08 +0100 Message-ID: References: <87ddf56f-c829-6aad-5b86-474359d282d4@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-lf0-f42.google.com ([209.85.215.42]:43873 "EHLO mail-lf0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751317AbeBHNEO (ORCPT ); Thu, 8 Feb 2018 08:04:14 -0500 Received: by mail-lf0-f42.google.com with SMTP id o89so6277076lfg.10 for ; Thu, 08 Feb 2018 05:04:14 -0800 (PST) In-Reply-To: <87ddf56f-c829-6aad-5b86-474359d282d4@pengutronix.de> Content-Language: en-US Sender: linux-can-owner@vger.kernel.org List-ID: To: Marc Kleine-Budde , "linux-can@vger.kernel.org" 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.