Message ID | 20200224225403.1650656-2-jeremy.linton@arm.com |
---|---|
State | Accepted |
Delegated to: | David Miller |
Headers | show |
Series | Add ACPI bindings to the genet | expand |
On 2/24/20 2:53 PM, Jeremy Linton wrote: > 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> Acked-by: Florian Fainelli <f.fainelli@gmail.com>
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c index 9bb9f37f21dc..3ab9ca7614d1 100644 --- a/drivers/net/phy/mdio_bus.c +++ b/drivers/net/phy/mdio_bus.c @@ -462,6 +462,23 @@ static struct class mdio_bus_class = { .dev_groups = mdio_bus_groups, }; +/** + * 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. diff --git a/include/linux/phy.h b/include/linux/phy.h index c570e162e05e..bd4ac49a9dbe 100644 --- a/include/linux/phy.h +++ b/include/linux/phy.h @@ -289,6 +289,7 @@ 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(+)