net: mdiobus: Introduce fwnode_mdiobus_register_phy()

Introduce fwnode_mdiobus_register_phy() to register PHYs on the
mdiobus. From the compatible string, identify whether the PHY is
c45 and based on this create a PHY device instance which is
registered on the mdiobus.

uninitialized symbol 'mii_ts'
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

Signed-off-by: Calvin Johnson <calvin.johnson@oss.nxp.com>

MAINTAINERS

@@ -6680,6 +6680,7 @@ F:	Documentation/devicetree/bindings/net/mdio*
 F:	Documentation/devicetree/bindings/net/qca,ar803x.yaml
 F:	Documentation/networking/phy.rst
 F:	drivers/net/mdio/
+F:	drivers/net/mdio/fwnode_mdio.c
 F:	drivers/net/mdio/of_mdio.c
 F:	drivers/net/pcs/
 F:	drivers/net/phy/

drivers/net/mdio/Kconfig

@@ -19,6 +19,15 @@ config MDIO_BUS
 	  reflects whether the mdio_bus/mdio_device code is built as a
 	  loadable module or built-in.
 
+config FWNODE_MDIO
+	def_tristate PHYLIB
+	depends on ACPI
+	depends on OF
+	depends on PHYLIB
+	select FIXED_PHY
+	help
+	  FWNODE MDIO bus (Ethernet PHY) accessors
+
 config OF_MDIO
 	def_tristate PHYLIB
 	depends on OF

drivers/net/mdio/Makefile

@@ -1,7 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0
 # Makefile for Linux MDIO bus drivers
 
-obj-$(CONFIG_OF_MDIO)	+= of_mdio.o
+obj-$(CONFIG_FWNODE_MDIO)	+= fwnode_mdio.o
+obj-$(CONFIG_OF_MDIO)		+= of_mdio.o
 
 obj-$(CONFIG_MDIO_ASPEED)		+= mdio-aspeed.o
 obj-$(CONFIG_MDIO_BCM_IPROC)		+= mdio-bcm-iproc.o

drivers/net/mdio/fwnode_mdio.c

@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * fwnode helpers for the MDIO (Ethernet PHY) API
+ *
+ * This file provides helper functions for extracting PHY device information
+ * out of the fwnode and using it to populate an mii_bus.
+ */
+
+#include <linux/acpi.h>
+#include <linux/of.h>
+#include <linux/of_mdio.h>
+#include <linux/phy.h>
+
+MODULE_AUTHOR("Calvin Johnson <calvin.johnson@oss.nxp.com>");
+MODULE_LICENSE("GPL");
+
+int fwnode_mdiobus_register_phy(struct mii_bus *bus,
+				struct fwnode_handle *child, u32 addr)
+{
+	struct mii_timestamper *mii_ts = NULL;
+	struct phy_device *phy;
+	bool is_c45 = false;
+	u32 phy_id;
+	int rc;
+
+	if (is_of_node(child)) {
+		mii_ts = of_find_mii_timestamper(to_of_node(child));
+		if (IS_ERR(mii_ts))
+			return PTR_ERR(mii_ts);
+	}
+
+	rc = fwnode_property_match_string(child, "compatible", "ethernet-phy-ieee802.3-c45");
+	if (rc >= 0)
+		is_c45 = true;
+
+	if (is_c45 || fwnode_get_phy_id(child, &phy_id))
+		phy = get_phy_device(bus, addr, is_c45);
+	else
+		phy = phy_device_create(bus, addr, phy_id, 0, NULL);
+	if (IS_ERR(phy)) {
+		unregister_mii_timestamper(mii_ts);
+		return PTR_ERR(phy);
+	}
+
+	if (is_acpi_node(child)) {
+		phy->irq = bus->irq[addr];
+
+		/* Associate the fwnode with the device structure so it
+		 * can be looked up later.
+		 */
+		phy->mdio.dev.fwnode = child;
+
+		/* All data is now stored in the phy struct, so register it */
+		rc = phy_device_register(phy);
+		if (rc) {
+			phy_device_free(phy);
+			fwnode_handle_put(phy->mdio.dev.fwnode);
+			return rc;
+		}
+	} else if (is_of_node(child)) {
+		rc = of_mdiobus_phy_device_register(bus, phy, to_of_node(child), addr);
+		if (rc) {
+			unregister_mii_timestamper(mii_ts);
+			phy_device_free(phy);
+			return rc;
+		}
+	}
+
+	/* phy->mii_ts may already be defined by the PHY driver. A
+	 * mii_timestamper probed via the device tree will still have
+	 * precedence.
+	 */
+	if (mii_ts)
+		phy->mii_ts = mii_ts;
+	return 0;
+}
+EXPORT_SYMBOL(fwnode_mdiobus_register_phy);

drivers/net/mdio/of_mdio.c

@@ -32,7 +32,7 @@ static int of_get_phy_id(struct device_node *device, u32 *phy_id)
 	return fwnode_get_phy_id(of_fwnode_handle(device), phy_id);
 }
 
-static struct mii_timestamper *of_find_mii_timestamper(struct device_node *node)
+struct mii_timestamper *of_find_mii_timestamper(struct device_node *node)
 {
 	struct of_phandle_args arg;
 	int err;
@@ -49,6 +49,7 @@ static struct mii_timestamper *of_find_mii_timestamper(struct device_node *node)
 
 	return register_mii_timestamper(arg.np, arg.args[0]);
 }
+EXPORT_SYMBOL(of_find_mii_timestamper);
 
 int of_mdiobus_phy_device_register(struct mii_bus *mdio, struct phy_device *phy,
 			      struct device_node *child, u32 addr)

include/linux/fwnode_mdio.h

@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * FWNODE helper for the MDIO (Ethernet PHY) API
+ */
+
+#ifndef __LINUX_FWNODE_MDIO_H
+#define __LINUX_FWNODE_MDIO_H
+
+#include <linux/phy.h>
+
+#if IS_ENABLED(CONFIG_FWNODE_MDIO)
+int fwnode_mdiobus_register_phy(struct mii_bus *bus,
+				struct fwnode_handle *child, u32 addr);
+
+#else /* CONFIG_FWNODE_MDIO */
+static inline int fwnode_mdiobus_register_phy(struct mii_bus *bus,
+					      struct fwnode_handle *child,
+					      u32 addr)
+{
+	return -EINVAL;
+}
+#endif
+
+#endif /* __LINUX_FWNODE_MDIO_H */

include/linux/of_mdio.h

@@ -31,6 +31,7 @@ struct mii_bus *of_mdio_find_bus(struct device_node *mdio_np);
 int of_phy_register_fixed_link(struct device_node *np);
 void of_phy_deregister_fixed_link(struct device_node *np);
 bool of_phy_is_fixed_link(struct device_node *np);
+struct mii_timestamper *of_find_mii_timestamper(struct device_node *np);
 int of_mdiobus_phy_device_register(struct mii_bus *mdio, struct phy_device *phy,
 				   struct device_node *child, u32 addr);
 
@@ -118,7 +119,10 @@ static inline bool of_phy_is_fixed_link(struct device_node *np)
 {
 	return false;
 }
-
+static inline struct mii_timestamper *of_find_mii_timestamper(struct device_node *np)
+{
+	return NULL;
+}
 static inline int of_mdiobus_phy_device_register(struct mii_bus *mdio,
 					    struct phy_device *phy,
 					    struct device_node *child, u32 addr)