1 // SPDX-License-Identifier: GPL-2.0
7 #include <linux/mdio-mux.h>
13 #define DRV_DESCRIPTION "MDIO bus multiplexer driver"
30 	struct mdio_mux_parent_bus *parent;  member
36  * The parent bus' lock is used to order access to the switch_fn.
38 static int mdio_mux_read(struct mii_bus *bus, int phy_id, int regnum)  in mdio_mux_read()  argument
40 	struct mdio_mux_child_bus *cb = bus->priv;  in mdio_mux_read()
41 	struct mdio_mux_parent_bus *pb = cb->parent;  in mdio_mux_read()
44 	mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX);  in mdio_mux_read()
45 	r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);  in mdio_mux_read()
49 	pb->current_child = cb->bus_number;  in mdio_mux_read()
51 	r = pb->mii_bus->read(pb->mii_bus, phy_id, regnum);  in mdio_mux_read()
53 	mutex_unlock(&pb->mii_bus->mdio_lock);  in mdio_mux_read()
59  * The parent bus' lock is used to order access to the switch_fn.
61 static int mdio_mux_write(struct mii_bus *bus, int phy_id,  in mdio_mux_write()  argument
64 	struct mdio_mux_child_bus *cb = bus->priv;  in mdio_mux_write()
65 	struct mdio_mux_parent_bus *pb = cb->parent;  in mdio_mux_write()
69 	mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX);  in mdio_mux_write()
70 	r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);  in mdio_mux_write()
74 	pb->current_child = cb->bus_number;  in mdio_mux_write()
76 	r = pb->mii_bus->write(pb->mii_bus, phy_id, regnum, val);  in mdio_mux_write()
78 	mutex_unlock(&pb->mii_bus->mdio_lock);  in mdio_mux_write()
100 		return -ENODEV;  in mdio_mux_init()
104 						   "mdio-parent-bus", 0);  in mdio_mux_init()
107 			return -ENODEV;  in mdio_mux_init()
111 			ret_val = -EPROBE_DEFER;  in mdio_mux_init()
117 		get_device(&parent_bus->dev);  in mdio_mux_init()
122 		ret_val = -ENOMEM;  in mdio_mux_init()
126 	pb->switch_data = data;  in mdio_mux_init()
127 	pb->switch_fn = switch_fn;  in mdio_mux_init()
128 	pb->current_child = -1;  in mdio_mux_init()
129 	pb->parent_id = parent_count++;  in mdio_mux_init()
130 	pb->mii_bus = parent_bus;  in mdio_mux_init()
132 	ret_val = -ENODEV;  in mdio_mux_init()
146 			ret_val = -ENOMEM;  in mdio_mux_init()
149 		cb->bus_number = v;  in mdio_mux_init()
150 		cb->parent = pb;  in mdio_mux_init()
152 		cb->mii_bus = mdiobus_alloc();  in mdio_mux_init()
153 		if (!cb->mii_bus) {  in mdio_mux_init()
154 			ret_val = -ENOMEM;  in mdio_mux_init()
158 		cb->mii_bus->priv = cb;  in mdio_mux_init()
160 		cb->mii_bus->name = "mdio_mux";  in mdio_mux_init()
161 		snprintf(cb->mii_bus->id, MII_BUS_ID_SIZE, "%x.%x",  in mdio_mux_init()
162 			 pb->parent_id, v);  in mdio_mux_init()
163 		cb->mii_bus->parent = dev;  in mdio_mux_init()
164 		cb->mii_bus->read = mdio_mux_read;  in mdio_mux_init()
165 		cb->mii_bus->write = mdio_mux_write;  in mdio_mux_init()
166 		r = of_mdiobus_register(cb->mii_bus, child_bus_node);  in mdio_mux_init()
169 				"Error: Failed to register MDIO bus for child %pOF\n",  in mdio_mux_init()
171 			mdiobus_free(cb->mii_bus);  in mdio_mux_init()
174 			cb->next = pb->children;  in mdio_mux_init()
175 			pb->children = cb;  in mdio_mux_init()
178 	if (pb->children) {  in mdio_mux_init()
186 	put_device(&parent_bus->dev);  in mdio_mux_init()
196 	struct mdio_mux_child_bus *cb = pb->children;  in mdio_mux_uninit()
199 		mdiobus_unregister(cb->mii_bus);  in mdio_mux_uninit()
200 		mdiobus_free(cb->mii_bus);  in mdio_mux_uninit()
201 		cb = cb->next;  in mdio_mux_uninit()
204 	put_device(&pb->mii_bus->dev);  in mdio_mux_uninit()