rtl8180: implement get_tsf op for mac80211

Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rtl818x/rtl8180_dev.c

@@ -761,6 +761,14 @@ static void rtl8180_configure_filter(struct ieee80211_hw *dev,
 	rtl818x_iowrite32(priv, &priv->map->RX_CONF, priv->rx_conf);
 }
 
+static u64 rtl8180_get_tsf(struct ieee80211_hw *dev)
+{
+	struct rtl8180_priv *priv = dev->priv;
+
+	return rtl818x_ioread32(priv, &priv->map->TSFT[0]) |
+	       (u64)(rtl818x_ioread32(priv, &priv->map->TSFT[1])) << 32;
+}
+
 static const struct ieee80211_ops rtl8180_ops = {
 	.tx			= rtl8180_tx,
 	.start			= rtl8180_start,
@@ -771,6 +779,7 @@ static const struct ieee80211_ops rtl8180_ops = {
 	.bss_info_changed	= rtl8180_bss_info_changed,
 	.prepare_multicast	= rtl8180_prepare_multicast,
 	.configure_filter	= rtl8180_configure_filter,
+	.get_tsf		= rtl8180_get_tsf,
 };
 
 static void rtl8180_eeprom_register_read(struct eeprom_93cx6 *eeprom)