cfg80211: Add documentation for antenna ops

Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

include/net/mac80211.h

@@ -1745,6 +1745,13 @@ enum ieee80211_ampdu_mlme_action {
  *	completion of the channel switch.
  *
  * @napi_poll: Poll Rx queue for incoming data frames.
+ *
+ * @set_antenna: Set antenna configuration (tx_ant, rx_ant) on the device.
+ *	Parameters are bitmaps of allowed antennas to use for TX/RX. Drivers may
+ *	reject TX/RX mask combinations they cannot support by returning -EINVAL
+ *	(also see nl80211.h @NL80211_ATTR_WIPHY_ANTENNA_TX).
+ *
+ * @get_antenna: Get current antenna configuration from device (tx_ant, rx_ant).
  */
 struct ieee80211_ops {
 	int (*tx)(struct ieee80211_hw *hw, struct sk_buff *skb);