ieee802154: add an mlme_ops call to retrieve PHY object

ops->get_phy should increment reference to wpan-phy. As we return
the external structure, we should do refcounting correctly.
Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>

include/net/ieee802154_netdev.h

@@ -74,8 +74,12 @@ static inline int mac_cb_type(struct sk_buff *skb)
 #define IEEE802154_MAC_SCAN_PASSIVE	2
 #define IEEE802154_MAC_SCAN_ORPHAN	3
 
+struct wpan_phy;
 /*
  * This should be located at net_device->ml_priv
+ *
+ * get_phy should increment the reference counting on returned phy.
+ * Use wpan_wpy_put to put that reference.
  */
 struct ieee802154_mlme_ops {
 	int (*assoc_req)(struct net_device *dev,
@@ -94,6 +98,8 @@ struct ieee802154_mlme_ops {
 	int (*scan_req)(struct net_device *dev,
 			u8 type, u32 channels, u8 page, u8 duration);
 
+	struct wpan_phy *(*get_phy)(const struct net_device *dev);
+
 	/*
 	 * FIXME: these should become the part of PIB/MIB interface.
 	 * However we still don't have IB interface of any kind

include/net/wpan-phy.h

@@ -44,6 +44,8 @@ struct wpan_phy {
 	char priv[0] __attribute__((__aligned__(NETDEV_ALIGN)));
 };
 
+#define to_phy(_dev)	container_of(_dev, struct wpan_phy, dev)
+
 struct wpan_phy *wpan_phy_alloc(size_t priv_size);
 static inline void wpan_phy_set_dev(struct wpan_phy *phy, struct device *dev)
 {