net: phy: add support for a common probe between shared PHYs

Shared PHYs (PHYs in the same hardware package) may have shared
registers and their drivers would usually need to share information.
There is currently a way to have a shared (part of the) init, by using
phy_package_init_once(). This patch extends the logic to share parts of
the probe to allow sharing the initialization of locks or resources
retrieval.
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/phy.h

@@ -244,7 +244,8 @@ struct phy_package_shared {
 };
 
 /* used as bit number in atomic bitops */
-#define PHY_SHARED_F_INIT_DONE 0
+#define PHY_SHARED_F_INIT_DONE  0
+#define PHY_SHARED_F_PROBE_DONE 1
 
 /*
  * The Bus class for PHYs.  Devices which provide access to
@@ -1566,14 +1567,25 @@ static inline int __phy_package_write(struct phy_device *phydev,
 	return __mdiobus_write(phydev->mdio.bus, shared->addr, regnum, val);
 }
 
-static inline bool phy_package_init_once(struct phy_device *phydev)
+static inline bool __phy_package_set_once(struct phy_device *phydev,
+					  unsigned int b)
 {
 	struct phy_package_shared *shared = phydev->shared;
 
 	if (!shared)
 		return false;
 
-	return !test_and_set_bit(PHY_SHARED_F_INIT_DONE, &shared->flags);
+	return !test_and_set_bit(b, &shared->flags);
+}
+
+static inline bool phy_package_init_once(struct phy_device *phydev)
+{
+	return __phy_package_set_once(phydev, PHY_SHARED_F_INIT_DONE);
+}
+
+static inline bool phy_package_probe_once(struct phy_device *phydev)
+{
+	return __phy_package_set_once(phydev, PHY_SHARED_F_PROBE_DONE);
 }
 
 extern struct bus_type mdio_bus_type;