@@ -260,6 +260,23 @@ static struct class mdio_bus_class = {
.dev_release = mdiobus_release,
};
+/**
+ * mdio_find_bus - Given the name of a mdiobus, find the mii_bus.
+ * @mdio_bus_np: Pointer to the mii_bus.
+ *
+ * Returns a reference to the mii_bus, or NULL if none found. The
+ * embedded struct device will have its reference count incremented,
+ * and this must be put_deviced'ed once the bus is finished with.
+ */
+struct mii_bus *mdio_find_bus(const char *mdio_name)
+{
+ struct device *d;
+
+ d = class_find_device_by_name(&mdio_bus_class, mdio_name);
+ return d ? to_mii_bus(d) : NULL;
+}
+EXPORT_SYMBOL(mdio_find_bus);
+
#if IS_ENABLED(CONFIG_OF_MDIO)
/**
* of_mdio_find_bus - Given an mii_bus node, find the mii_bus.
@@ -273,6 +273,7 @@ static inline struct mii_bus *devm_mdiobus_alloc(struct device *dev)
return devm_mdiobus_alloc_size(dev, 0);
}
+struct mii_bus *mdio_find_bus(const char *mdio_name);
void devm_mdiobus_free(struct device *dev, struct mii_bus *bus);
struct phy_device *mdiobus_scan(struct mii_bus *bus, int addr);
It appears most ethernet drivers follow one of two main strategies for mdio bus/phy management. A monolithic model where the net driver itself creates, probes and uses the phy, and one where an external mdio/phy driver instantiates the mdio bus/phy and the net driver only attaches to a known phy. Usually in this latter model the phys are discovered via DT relationships or simply phy name/address hardcoding. This is a shame because modern well behaved mdio buses are self describing and can be probed. The mdio layer itself is fully capable of this, yet there isn't a clean way for a standalone net driver to attach and enumerate the discovered devices. This is because outside of of_mdio_find_bus() there isn't a straightforward way to acquire the mii_bus pointer. So, lets add a mdio_find_bus which can return the mii_bus based only on its name. Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> --- drivers/net/phy/mdio_bus.c | 17 +++++++++++++++++ include/linux/phy.h | 1 + 2 files changed, 18 insertions(+)