[PATCH v2 net-next] net: phy: make mdio consumer / device layer a separate module

[PATCH v2 net-next] net: phy: make mdio consumer / device layer a separate module

[Heiner Kallweit]

After having factored out the provider part from mdio_bus.c, we can
make the mdio consumer / device layer a separate module. This also
allows to remove Kconfig symbol MDIO_DEVICE.
The module init / exit functions from mdio_bus.c no longer have to be
called from phy_device.c. The link order defined in
drivers/net/phy/Makefile ensures that init / exit functions are called
in the right order.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
v2:
- export mdio_device_bus_match
---
 drivers/net/mdio/Kconfig      | 16 ++--------------
 drivers/net/phy/Kconfig       |  2 +-
 drivers/net/phy/Makefile      | 18 +++++-------------
 drivers/net/phy/mdio_bus.c    | 14 ++++++--------
 drivers/net/phy/mdio_device.c |  1 +
 drivers/net/phy/phy_device.c  | 11 ++---------
 include/linux/phy.h           |  3 ---
 7 files changed, 17 insertions(+), 48 deletions(-)

diff --git a/drivers/net/mdio/Kconfig b/drivers/net/mdio/Kconfig
index d3219ca19..7db40aaa0 100644
--- a/drivers/net/mdio/Kconfig
+++ b/drivers/net/mdio/Kconfig
@@ -3,21 +3,10 @@
 # MDIO Layer Configuration
 #
 
-menuconfig MDIO_DEVICE
-	tristate "MDIO bus device drivers"
-	help
-	  MDIO devices and driver infrastructure code.
-
-if MDIO_DEVICE
-
 config MDIO_BUS
-	tristate
-	default m if PHYLIB=m
-	default MDIO_DEVICE
+	tristate "MDIO bus consumer layer"
 	help
-	  This internal symbol is used for link time dependencies and it
-	  reflects whether the mdio_bus/mdio_device code is built as a
-	  loadable module or built-in.
+	  MDIO bus consumer layer
 
 if PHYLIB
 
@@ -291,4 +280,3 @@ config MDIO_BUS_MUX_MMIOREG
 
 
 endif
-endif
diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index 677d56e06..127a9fd0f 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -14,7 +14,7 @@ config PHYLINK
 
 menuconfig PHYLIB
 	tristate "PHY Device support and infrastructure"
-	select MDIO_DEVICE
+	select MDIO_BUS
 	help
 	  Ethernet controllers are usually attached to PHY
 	  devices.  This option provides infrastructure for
diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index 59ac3a9a3..7de69320a 100644
--- a/drivers/net/phy/Makefile
+++ b/drivers/net/phy/Makefile
@@ -6,27 +6,19 @@ libphy-y			:= phy.o phy-c45.o phy-core.o phy_device.o \
 				   phy_package.o phy_caps.o mdio_bus_provider.o
 mdio-bus-y			+= mdio_bus.o mdio_device.o
 
-ifdef CONFIG_MDIO_DEVICE
-obj-y				+= mdio-boardinfo.o
-endif
-
-# PHYLIB implies MDIO_DEVICE, in that case, we have a bunch of circular
-# dependencies that does not make it possible to split mdio-bus objects into a
-# dedicated loadable module, so we bundle them all together into libphy.ko
 ifdef CONFIG_PHYLIB
-libphy-y			+= $(mdio-bus-y)
-# the stubs are built-in whenever PHYLIB is built-in or module
-obj-y				+= stubs.o
-else
-obj-$(CONFIG_MDIO_DEVICE)	+= mdio-bus.o
+# built-in whenever PHYLIB is built-in or module
+obj-y				+= stubs.o mdio-boardinfo.o
 endif
-obj-$(CONFIG_PHYLIB)		+= mdio_devres.o
+
 libphy-$(CONFIG_SWPHY)		+= swphy.o
 libphy-$(CONFIG_LED_TRIGGER_PHY)	+= phy_led_triggers.o
 libphy-$(CONFIG_OPEN_ALLIANCE_HELPERS) += open_alliance_helpers.o
 
+obj-$(CONFIG_MDIO_BUS)		+= mdio-bus.o
 obj-$(CONFIG_PHYLINK)		+= phylink.o
 obj-$(CONFIG_PHYLIB)		+= libphy.o
+obj-$(CONFIG_PHYLIB)		+= mdio_devres.o
 
 obj-$(CONFIG_NETWORK_PHY_TIMESTAMPING) += mii_timestamper.o
 
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index f5ccbe33a..a6bcb0fee 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -988,7 +988,7 @@ const struct bus_type mdio_bus_type = {
 };
 EXPORT_SYMBOL(mdio_bus_type);
 
-int __init mdio_bus_init(void)
+static int __init mdio_bus_init(void)
 {
 	int ret;
 
@@ -1002,16 +1002,14 @@ int __init mdio_bus_init(void)
 	return ret;
 }
 
-#if IS_ENABLED(CONFIG_PHYLIB)
-void mdio_bus_exit(void)
+static void __exit mdio_bus_exit(void)
 {
 	class_unregister(&mdio_bus_class);
 	bus_unregister(&mdio_bus_type);
 }
-EXPORT_SYMBOL_GPL(mdio_bus_exit);
-#else
-module_init(mdio_bus_init);
-/* no module_exit, intentional */
+
+subsys_initcall(mdio_bus_init);
+module_exit(mdio_bus_exit);
+
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("MDIO bus/device layer");
-#endif
diff --git a/drivers/net/phy/mdio_device.c b/drivers/net/phy/mdio_device.c
index e747ee63c..cce3f405d 100644
--- a/drivers/net/phy/mdio_device.c
+++ b/drivers/net/phy/mdio_device.c
@@ -45,6 +45,7 @@ int mdio_device_bus_match(struct device *dev, const struct device_driver *drv)
 
 	return strcmp(mdiodev->modalias, drv->name) == 0;
 }
+EXPORT_SYMBOL_GPL(mdio_device_bus_match);
 
 struct mdio_device *mdio_device_create(struct mii_bus *bus, int addr)
 {
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index f85c172c4..c06a1ff9b 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -3557,19 +3557,15 @@ static int __init phy_init(void)
 	phylib_register_stubs();
 	rtnl_unlock();
 
-	rc = mdio_bus_init();
-	if (rc)
-		goto err_ethtool_phy_ops;
-
 	rc = phy_caps_init();
 	if (rc)
-		goto err_mdio_bus;
+		goto err_ethtool_phy_ops;
 
 	features_init();
 
 	rc = phy_driver_register(&genphy_c45_driver, THIS_MODULE);
 	if (rc)
-		goto err_mdio_bus;
+		goto err_ethtool_phy_ops;
 
 	rc = phy_driver_register(&genphy_driver, THIS_MODULE);
 	if (rc)
@@ -3579,8 +3575,6 @@ static int __init phy_init(void)
 
 err_c45:
 	phy_driver_unregister(&genphy_c45_driver);
-err_mdio_bus:
-	mdio_bus_exit();
 err_ethtool_phy_ops:
 	rtnl_lock();
 	phylib_unregister_stubs();
@@ -3594,7 +3588,6 @@ static void __exit phy_exit(void)
 {
 	phy_driver_unregister(&genphy_c45_driver);
 	phy_driver_unregister(&genphy_driver);
-	mdio_bus_exit();
 	rtnl_lock();
 	phylib_unregister_stubs();
 	ethtool_set_ethtool_phy_ops(NULL);
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 7c29d346d..92a88b5ce 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -2033,9 +2033,6 @@ int phy_ethtool_set_link_ksettings(struct net_device *ndev,
 				   const struct ethtool_link_ksettings *cmd);
 int phy_ethtool_nway_reset(struct net_device *ndev);
 
-int __init mdio_bus_init(void);
-void mdio_bus_exit(void);
-
 int phy_ethtool_get_strings(struct phy_device *phydev, u8 *data);
 int phy_ethtool_get_sset_count(struct phy_device *phydev);
 int phy_ethtool_get_stats(struct phy_device *phydev,
-- 
2.49.0

Re: [PATCH v2 net-next] net: phy: make mdio consumer / device layer a separate module

[Paolo Abeni]

On 5/15/25 10:11 AM, Heiner Kallweit wrote:
> After having factored out the provider part from mdio_bus.c, we can
> make the mdio consumer / device layer a separate module. This also
> allows to remove Kconfig symbol MDIO_DEVICE.
> The module init / exit functions from mdio_bus.c no longer have to be
> called from phy_device.c. The link order defined in
> drivers/net/phy/Makefile ensures that init / exit functions are called
> in the right order.
> 
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>

Makes sense to me, and I think the best path is merge it now and allow
the bot to crunch some possible weird/problematic conf I could not foresee.

/P

Re: [PATCH v2 net-next] net: phy: make mdio consumer / device layer a separate module

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Paolo Abeni <pabeni@redhat.com>:

On Thu, 15 May 2025 10:11:54 +0200 you wrote:
> After having factored out the provider part from mdio_bus.c, we can
> make the mdio consumer / device layer a separate module. This also
> allows to remove Kconfig symbol MDIO_DEVICE.
> The module init / exit functions from mdio_bus.c no longer have to be
> called from phy_device.c. The link order defined in
> drivers/net/phy/Makefile ensures that init / exit functions are called
> in the right order.
> 
> [...]

Here is the summary with links:
  - [v2,net-next] net: phy: make mdio consumer / device layer a separate module
    https://git.kernel.org/netdev/net-next/c/31be641d7426

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
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