[PATCH 2/5] mdio_bus: Port of_mdio_find_bus() from Linux kernel

[Andrey Smirnov]

Port of_mdio_find_bus() from Linux kernel. This function is used in
MDIO multiplexor infrastructure added in following commit.

Signed-off-by: Andrey Smirnov <andrew.smirnov at gmail.com>
---
 drivers/net/phy/mdio_bus.c | 27 +++++++++++++++++++++++++++
 include/linux/phy.h        |  2 ++
 2 files changed, 29 insertions(+)

diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 012b90e83..6ae85692d 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -206,6 +206,33 @@ struct mii_bus *mdiobus_get_bus(int busnum)
 	return NULL;
 }
 
+/**
+ * of_mdio_find_bus - Given an mii_bus node, find the mii_bus.
+ * @mdio_bus_np: Pointer to the mii_bus.
+ *
+ * Returns a reference to the mii_bus, or NULL if none found.
+ *
+ * Because the association of a device_node and mii_bus is made via
+ * mdiobus_register(), the mii_bus cannot be found before it is
+ * registered with mdiobus_register().
+ *
+ */
+struct mii_bus *of_mdio_find_bus(struct device_node *mdio_bus_np)
+{
+	struct mii_bus *mii;
+
+	if (!mdio_bus_np)
+		return NULL;
+
+	for_each_mii_bus(mii)
+		if (mii->dev.device_node == mdio_bus_np)
+			return mii;
+
+	return NULL;
+}
+EXPORT_SYMBOL(of_mdio_find_bus);
+
+
 /**
  * mdio_bus_match - determine if given PHY driver supports the given PHY device
  * @dev: target PHY device
diff --git a/include/linux/phy.h b/include/linux/phy.h
index d7b10afbc..809f06fb1 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -116,6 +116,8 @@ int mdiobus_detect(struct device_d *dev);
 
 struct mii_bus *mdiobus_get_bus(int busnum);
 
+struct mii_bus *of_mdio_find_bus(struct device_node *mdio_bus_np);
+
 /**
  * mdiobus_read - Convenience function for reading a given MII mgmt register
  * @bus: the mii_bus struct
-- 
2.14.3