ath: Add config option for DFS support

This patch adds a config option to enable DFS in ath9k and ath10k
drivers (with ath10k you need the AP-branch firmware). I'm not entirely
sure about the regulatory compliance issues, though. As far as I
understand, enabling the DFS_CERTIFIED config options implies that the
device is certified for DFS. No doubt the original firmware has obtained
such a certification, but not with the open source drivers. I suppose
that as long as this is disabled in default builds (like ATH_USER_REGD)
everything should be fine, but it would be nice to have out-of-the-box
OpenWrt support for DFS. I'm also not sure whether the description of
the configuration option should say something about regulatory compliance.

Signed-off-by: Matti Laakso <malaakso@elisanet.fi>
Signed-off-by: Felix Fietkau <nbd@openwrt.org>

SVN-Revision: 40692

package/kernel/mac80211/Makefile

@@ -39,6 +39,7 @@ PKG_CONFIG_DEPENDS:= \
 	CONFIG_PACKAGE_MAC80211_DEBUGFS \
 	CONFIG_PACKAGE_MAC80211_MESH \
 	CONFIG_PACKAGE_ATH_DEBUG \
+	CONFIG_PACKAGE_ATH_DFS \
 	CONFIG_PACKAGE_B43_DEBUG \
 	CONFIG_PACKAGE_B43_PIO \
 	CONFIG_PACKAGE_B43_N_PHY \
@@ -510,6 +511,16 @@ define KernelPackage/ath/config
 		help
 		  Say Y, if you want to debug atheros wireless drivers.
 		  Right now only ath9k makes use of this.
+
+	config PACKAGE_ATH_DFS
+		bool "Enable DFS support"
+		help
+		  Dynamic frequency selection (DFS) is required for most of the 5 GHz band
+		  channels in Europe, US, and Japan.
+
+		  Select this option if you want to use such channels. Only EU (ETSI) DFS
+		  is supported at the moment.
+
   endif
 endef
 
@@ -1380,6 +1391,7 @@ config-$(call config_package,lib80211) += LIB80211 LIB80211_CRYPT_WEP LIB80211_C
 
 config-$(call config_package,ath) += ATH_CARDS ATH_COMMON
 config-$(CONFIG_PACKAGE_ATH_DEBUG) += ATH_DEBUG ATH10K_DEBUG
+config-$(CONFIG_PACKAGE_ATH_DFS) += ATH9K_DFS_CERTIFIED ATH10K_DFS_CERTIFIED
 
 config-$(call config_package,ath9k) += ATH9K
 config-$(call config_package,ath9k-common) += ATH9K_COMMON