After all, how can I program ATSAMR21 on linux environment?
I have a reasonable ATMEL ICE that is working fine, despite they forgot to bring RESET pin at 100 mils 6 pin header for SWD interface.
For unknown reason, it's tied to GND so all SWD pins are there (including unused SWO) but TRSTN.
Anyhow, after little cable hack everything is working now and Atmel Studio is detecting my ATSAMR21E18A just fine.
I noticed that avrdude or avarice doesn't know about SAM devices. Still avarice sounds promising, implementing EDBG protocol.
There is a workaround out there or something?