Using the following /etc/wpa_supplicant.conf :
## -- Example AD-HOC network
ap_scan=2 # mandatory for AD-HOC mode
e.g. with fixed IPs on both sides allows to communicate without access point between two Wi-ME 9210.
It should also work on Wi-i.MX51/53 using Redpine chip.
The instructions from Digi Embedded Linux documentation section 10.8.1.2 using wpa_cli seem not to be complete, since at least one of the devices should define a channel or frequency. see also https://wiki.archlinux.org/index.php/ad-hoc_networking
The Atheros AR6x03 driver/chip in the Wi-i.MX28/Wi-i.MX6 does not support Ad-hoc mode, it supports Wi-Fi Direct
Jun 06, 2019