Hi, I understand and why not. But: 1 - we were inspired by the existing in some socket-can drivers 2 - these identifiers are not literally stored in an eeprom 3 - the memory storage address is not necessarily an information known by the user, is different depending on the CAN-USB interface and can be subject to change over time 4 - reading sysfs makes the assignment of an interface name much easier IMHO Maybe you have another suggestion for the location of this entry in sysfs? — Stéphane De: Marc Kleine-Budde Envoyé: Mercredi 17 novembre 2021 16:16 À: Stéphane Grosjean Cc: linux-can Mailing List Objet: Re: [PATCH 6/6] can: peak_usb: add sysfs interface to internal device user value On 17.11.2021 16:01:32, Stephane Grosjean wrote: > This patch adds under /sys/class/net/canX a new group named "peak_usb" > which contains a "dev_num" entry accessible for reading (display in > decimal of the numerical value stored in non-volatile memory of the USB > device) and also for writing (modification by the user of this value). > > Signed-off-by: Stephane Grosjean <s.grosjean@xxxxxxxxxxxxxxx> Please have a look at the ethtool eeprom interface: | ethtool -e|--eeprom-dump devname [raw on|off] [offset N] [length N] | ethtool -E|--change-eeprom devname [magic N] [offset N] [length N] [value N] That looks better than adding a custom sysfs entry. Marc -- Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung West/Dortmund | Phone: +49-231-2826-924 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- PEAK-System Technik GmbH Sitz der Gesellschaft Darmstadt - HRB 9183 Geschaeftsfuehrung: Alexander Gach / Uwe Wilhelm Unsere Datenschutzerklaerung mit wichtigen Hinweisen zur Behandlung personenbezogener Daten finden Sie unter www.peak-system.com/Datenschutz.483.0.html