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From ce69e2162f158d9d4a0e513971d02dabc7d14cb7 Mon Sep 17 00:00:00 2001
From: Jeremy Linton <jeremy.linton@arm.com>
Date: Mon, 24 Feb 2020 16:53:58 -0600
Subject: [PATCH] mdio_bus: Add generic mdio_find_bus()
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>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
drivers/net/phy/mdio_bus.c | 17 +++++++++++++++++
include/linux/phy.h | 1 +
2 files changed, 18 insertions(+)
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -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.
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -273,6 +273,7 @@ static inline struct mii_bus *devm_mdiob
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);
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