of: mdio: provide devm_of_mdiobus_register()

Implement a managed variant of of_mdiobus_register(). We need to make
mdio_devres into its own module because otherwise we'd hit circular
sumbol dependencies between phylib and of_mdio.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/driver-api/driver-model/devres.rst

@@ -343,6 +343,7 @@ MDIO
   devm_mdiobus_alloc()
   devm_mdiobus_alloc_size()
   devm_mdiobus_register()
+  devm_of_mdiobus_register()
 
 MEM
   devm_free_pages()

drivers/net/phy/Makefile

@@ -3,7 +3,8 @@
 
 libphy-y			:= phy.o phy-c45.o phy-core.o phy_device.o \
 				   linkmode.o
-mdio-bus-y			+= mdio_bus.o mdio_device.o mdio_devres.o
+mdio-bus-y			+= mdio_bus.o mdio_device.o
+mdio-devres-y			+= mdio_devres.o
 
 ifdef CONFIG_MDIO_DEVICE
 obj-y				+= mdio-boardinfo.o
@@ -17,6 +18,7 @@ libphy-y			+= $(mdio-bus-y)
 else
 obj-$(CONFIG_MDIO_DEVICE)	+= mdio-bus.o
 endif
+obj-$(CONFIG_MDIO_DEVICE)	+= mdio-devres.o
 libphy-$(CONFIG_SWPHY)		+= swphy.o
 libphy-$(CONFIG_LED_TRIGGER_PHY)	+= phy_led_triggers.o
 

drivers/net/phy/mdio_devres.c

 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #include <linux/device.h>
+#include <linux/of_mdio.h>
 #include <linux/phy.h>
 #include <linux/stddef.h>
 
@@ -94,3 +95,39 @@ int __devm_mdiobus_register(struct device *dev, struct mii_bus *bus,
 	return 0;
 }
 EXPORT_SYMBOL(__devm_mdiobus_register);
+
+#if IS_ENABLED(CONFIG_OF_MDIO)
+/**
+ * devm_of_mdiobus_register - Resource managed variant of of_mdiobus_register()
+ * @dev:	Device to register mii_bus for
+ * @mdio:	MII bus structure to register
+ * @np:		Device node to parse
+ */
+int devm_of_mdiobus_register(struct device *dev, struct mii_bus *mdio,
+			     struct device_node *np)
+{
+	struct mdiobus_devres *dr;
+	int ret;
+
+	if (WARN_ON(!devres_find(dev, devm_mdiobus_free,
+				 mdiobus_devres_match, mdio)))
+		return -EINVAL;
+
+	dr = devres_alloc(devm_mdiobus_unregister, sizeof(*dr), GFP_KERNEL);
+	if (!dr)
+		return -ENOMEM;
+
+	ret = of_mdiobus_register(mdio, np);
+	if (ret) {
+		devres_free(dr);
+		return ret;
+	}
+
+	dr->mii = mdio;
+	devres_add(dev, dr);
+	return 0;
+}
+EXPORT_SYMBOL(devm_of_mdiobus_register);
+#endif /* CONFIG_OF_MDIO */
+
+MODULE_LICENSE("GPL");

include/linux/of_mdio.h

@@ -8,12 +8,15 @@
 #ifndef __LINUX_OF_MDIO_H
 #define __LINUX_OF_MDIO_H
 
+#include <linux/device.h>
 #include <linux/phy.h>
 #include <linux/of.h>
 
 #if IS_ENABLED(CONFIG_OF_MDIO)
 bool of_mdiobus_child_is_phy(struct device_node *child);
 int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np);
+int devm_of_mdiobus_register(struct device *dev, struct mii_bus *mdio,
+			     struct device_node *np);
 struct phy_device *of_phy_find_device(struct device_node *phy_np);
 struct phy_device *
 of_phy_connect(struct net_device *dev, struct device_node *phy_np,