As already explained in here, all Linux drivers are documented here: http://wireless.kernel.org/en/users/Drivers.

Most images offered on the OpenWrt download page already include the wireless drivers, if yours doesn't, you can install them with opkg after flashing OpenWrt onto your router.

With opkg simply do, e.g.:

opkg update
opkg install kmod-ath9k
rm -f /etc/config/wireless; wifi detect > /etc/config/wireless

because of the package dependencies, all necessary packages will be installed as well. The overall size can be considerable!

Note1: For AP mode and/or for encryption better then WEP (Wired Equivalent Privacy), you may require additional software, see →hostapd!
Note2: We strongly discourage you from using WEP!.

Entire configuration is done via UCI in the files:

• → /etc/config/wireless
• → /etc/config/network

Also see recipes for proven scenarios, and only in case you want to do stuff manually, consult wireless.utilities.

Package	Dependencies
kmod-ath9k
	kmod-ath9k-common
		kmod-ath
			kmod-mac80211
				kmod-crypto-core
				kmod-crypto-arc 4	kmod-crypto-core
				kmod-crypto-aes
				kmod-cfg80211	wireless-tools
					iw	libnl-tiny
					crda
Overall size = 486.450 Bytes
kmod-ath5k
	kmod-ath
		kmod-mac80211
			kmod-crypto-core
			kmod-crypto-arc 4	kmod-crypto-core
			kmod-crypto-aes
			kmod-cfg80211	wireless-tools
				iw	libnl-tiny
				crda
Overall size = 308.902 Bytes
kmod-b43
	kmod-ssb
	kmod-bcma
	kmod-mac80211
		kmod-crypto-core
		kmod-crypto-arc 4	kmod-crypto-core
		kmod-crypto-aes
		kmod-cfg80211	wireless-tools
			iw	libnl-tiny
			crda
Overall size = 561.201 Bytes

Name	Size	Description
kmod-ath9k	155.684	This module adds support for wireless adapters based on Atheros IEEE 802.11n AR5008 and AR9001 family of chipsets.
kmod-ath9k-htc	113.441	This module adds support for wireless adapters based on Atheros USB AR9271 and AR7010 family of chipsets.
kmod-ath9k-common	104.136	Atheros 802.11n wireless devices (common code for ath9k and ath9k_htc)
kmod-ath5k	82.272	This module adds support for wireless adapters based on Atheros 5xxx chipset.
kmod-ath	10.059	This module contains some common parts needed by Atheros Wireless drivers.
kmod-b43	210.860	Kernel module for Broadcom 43xx wireless support (mac80211 stack)
kmod-mac80211	139.372	Generic IEEE 802.11 Networking Stack (mac80211)
kmod-cfg80211	93.696	cfg80211 is the Linux wireless LAN (802.11) configuration API.
iw	32.100	cfg80211 interface configuration utility
wireless-tools	23.153	Contains iwconfig, iwlist and iwpriv; tools for configuring wireless adapters implementing the WExt.
crda	9.627	The Central Regulatory Domain Agent serves one purpose: tell Linux kernel what to enforce. In essence it is a udev helper for communication between the kernel and userspace. You only need to run this manually for debugging purposes. For manual changing of regulatory domains use iw (iw reg set) or wpa-supplicant (feature yet to be added).
libnl-tiny	13.529	This package contains a stripped down version of libnl

Due to r31954 tweaking the regulatory.bin to enbale channel 13 and 14 is no longer an option.

http://wireless.kernel.org/en/users/Drivers