This page describes the support status of mwlwifi. This mac80211 based wifi driver is open source with a closed source binary for the Marvell 88W8x64 802.11ac series found in Linksys WRT AC Series devices.
Marvell maintains the source code at https://github.com/kaloz/mwlwifi.
Bugs and issues can be reported at https://github.com/kaloz/mwlwifi/issues.
The latest git commits for mwlwifi in the official OpenWrt repository.
There are some special considerations listed on github to take into account using features such as the 5GHz channels.