GitLab

- linux module
- use priv->{read,write}_reg instead of direct calls
- add ctu_can_fd_reset
- number buffers from 0, not from 1
- fix: ctu_can_fd_set_mode: oneshot, berr_reporting
- ctu_can_fd_read_err_ctrs: requires non-null params
- ctu_can_fd_read_rx_frame: option to fetch the first ID word sooner
  to determine FD/non-FD frame for skb allocation
- ctu_can_fd_insert_frame: add param isfd, fix for RTR
- minor optimizations

TODO: split this large commit

kernel! Thus low-level driver can be directly used with Socket CAN.