diff --git a/docs/wireless.tex b/docs/wireless.tex
index 16dcd689fe..efb07eafb4 100644
--- a/docs/wireless.tex
+++ b/docs/wireless.tex
@@ -117,6 +117,7 @@ config wifi-iface
     option key2     key 2
     option key3     key 3
     option key4     key 4
+    option passphrase 0,1
     option server   ip address
     option port     port
     option hidden   0,1
@@ -219,6 +220,13 @@ config wifi-iface
     \item \texttt{key, key1, key2, key3, key4} (wep, wpa and psk) \\
         WEP key, WPA key (PSK mode) or the RADIUS shared secret (WPA RADIUS mode)
 
+    \item \texttt{passphrase} (wpa) \\
+        0 treats the wpa psk as a text passphrase; 1 treats wpa psk as
+        encoded passphrase. You can generate an encoded passphrase with
+        the wpa\_passphrase utility. This is especially useful if your
+        passphrase contains special characters. This option only works
+        when using mac80211 or atheros type devices.
+
     \item \texttt{server} (wpa) \\
         The RADIUS server ip address