Comment # 3 on bug 1162863 from Jiri Slaby

Unfortunately that model was never implemented upstream and I seriously doubt
it ever will. Doesn't broadcom-wl work for you?

In any way you can contact the developers directly and ask them about the
status/plans:
https://wireless.wiki.kernel.org/en/users/drivers/brcm80211#contact_info

Feel free to reopen this once upstream adds the support.