net: phy: Allow pre-declaration of MDIO devices

Allow board support code to collect pre-declarations for MDIO devices by
registering them with mdiobus_register_board_info(). SPI and I2C buses
have a similar feature, we were missing this for MDIO devices, but this
is particularly useful for e.g: MDIO-connected switches which need to
provide their port layout (often board-specific) to a MDIO Ethernet
switch driver.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/mdio.h b/include/linux/mdio.h
index 55a80d7..ca08ab1 100644
--- a/include/linux/mdio.h
+++ b/include/linux/mdio.h
@@ -10,6 +10,7 @@
 #define __LINUX_MDIO_H__
 
 #include <uapi/linux/mdio.h>
+#include <linux/mod_devicetable.h>
 
 struct mii_bus;
 
@@ -29,6 +30,7 @@ struct mdio_device {
 
 	const struct dev_pm_ops *pm_ops;
 	struct mii_bus *bus;
+	char modalias[MDIO_NAME_SIZE];
 
 	int (*bus_match)(struct device *dev, struct device_driver *drv);
 	void (*device_free)(struct mdio_device *mdiodev);
@@ -71,6 +73,7 @@ int mdio_device_register(struct mdio_device *mdiodev);
 void mdio_device_remove(struct mdio_device *mdiodev);
 int mdio_driver_register(struct mdio_driver *drv);
 void mdio_driver_unregister(struct mdio_driver *drv);
+int mdio_device_bus_match(struct device *dev, struct device_driver *drv);
 
 static inline bool mdio_phy_id_is_c45(int phy_id)
 {
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 8a57f0b..8850fca 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -501,6 +501,7 @@ struct platform_device_id {
 	kernel_ulong_t driver_data;
 };
 
+#define MDIO_NAME_SIZE		32
 #define MDIO_MODULE_PREFIX	"mdio:"
 
 #define MDIO_ID_FMT "%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d"
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 28ae9ea..d9bdf53 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -886,6 +886,25 @@ void mdio_bus_exit(void);
 
 extern struct bus_type mdio_bus_type;
 
+struct mdio_board_info {
+	const char	*bus_id;
+	char		modalias[MDIO_NAME_SIZE];
+	int		mdio_addr;
+	const void	*platform_data;
+};
+
+#if IS_ENABLED(CONFIG_PHYLIB)
+int mdiobus_register_board_info(const struct mdio_board_info *info,
+				unsigned int n);
+#else
+static inline int mdiobus_register_board_info(const struct mdio_board_info *i,
+					      unsigned int n)
+{
+	return 0;
+}
+#endif
+
+
 /**
  * module_phy_driver() - Helper macro for registering PHY drivers
  * @__phy_drivers: array of PHY drivers to register