1a9770eacSAndrew Lunn // SPDX-License-Identifier: GPL-2.0 2a9770eacSAndrew Lunn /* 3a9770eacSAndrew Lunn * Copyright (C) 2011, 2012 Cavium, Inc. 4a9770eacSAndrew Lunn */ 5a9770eacSAndrew Lunn 6a9770eacSAndrew Lunn #include <linux/device.h> 7*1bf34366SCalvin Johnson #include <linux/mdio-mux.h> 8a9770eacSAndrew Lunn #include <linux/module.h> 9*1bf34366SCalvin Johnson #include <linux/of_mdio.h> 10a9770eacSAndrew Lunn #include <linux/phy.h> 11*1bf34366SCalvin Johnson #include <linux/platform_device.h> 12a9770eacSAndrew Lunn 13a9770eacSAndrew Lunn #define DRV_DESCRIPTION "MDIO bus multiplexer driver" 14a9770eacSAndrew Lunn 15a9770eacSAndrew Lunn struct mdio_mux_child_bus; 16a9770eacSAndrew Lunn 17a9770eacSAndrew Lunn struct mdio_mux_parent_bus { 18a9770eacSAndrew Lunn struct mii_bus *mii_bus; 19a9770eacSAndrew Lunn int current_child; 20a9770eacSAndrew Lunn int parent_id; 21a9770eacSAndrew Lunn void *switch_data; 22a9770eacSAndrew Lunn int (*switch_fn)(int current_child, int desired_child, void *data); 23a9770eacSAndrew Lunn 24a9770eacSAndrew Lunn /* List of our children linked through their next fields. */ 25a9770eacSAndrew Lunn struct mdio_mux_child_bus *children; 26a9770eacSAndrew Lunn }; 27a9770eacSAndrew Lunn 28a9770eacSAndrew Lunn struct mdio_mux_child_bus { 29a9770eacSAndrew Lunn struct mii_bus *mii_bus; 30a9770eacSAndrew Lunn struct mdio_mux_parent_bus *parent; 31a9770eacSAndrew Lunn struct mdio_mux_child_bus *next; 32a9770eacSAndrew Lunn int bus_number; 33a9770eacSAndrew Lunn }; 34a9770eacSAndrew Lunn 35a9770eacSAndrew Lunn /* 36a9770eacSAndrew Lunn * The parent bus' lock is used to order access to the switch_fn. 37a9770eacSAndrew Lunn */ 38a9770eacSAndrew Lunn static int mdio_mux_read(struct mii_bus *bus, int phy_id, int regnum) 39a9770eacSAndrew Lunn { 40a9770eacSAndrew Lunn struct mdio_mux_child_bus *cb = bus->priv; 41a9770eacSAndrew Lunn struct mdio_mux_parent_bus *pb = cb->parent; 42a9770eacSAndrew Lunn int r; 43a9770eacSAndrew Lunn 44a9770eacSAndrew Lunn mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX); 45a9770eacSAndrew Lunn r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data); 46a9770eacSAndrew Lunn if (r) 47a9770eacSAndrew Lunn goto out; 48a9770eacSAndrew Lunn 49a9770eacSAndrew Lunn pb->current_child = cb->bus_number; 50a9770eacSAndrew Lunn 51a9770eacSAndrew Lunn r = pb->mii_bus->read(pb->mii_bus, phy_id, regnum); 52a9770eacSAndrew Lunn out: 53a9770eacSAndrew Lunn mutex_unlock(&pb->mii_bus->mdio_lock); 54a9770eacSAndrew Lunn 55a9770eacSAndrew Lunn return r; 56a9770eacSAndrew Lunn } 57a9770eacSAndrew Lunn 58a9770eacSAndrew Lunn /* 59a9770eacSAndrew Lunn * The parent bus' lock is used to order access to the switch_fn. 60a9770eacSAndrew Lunn */ 61a9770eacSAndrew Lunn static int mdio_mux_write(struct mii_bus *bus, int phy_id, 62a9770eacSAndrew Lunn int regnum, u16 val) 63a9770eacSAndrew Lunn { 64a9770eacSAndrew Lunn struct mdio_mux_child_bus *cb = bus->priv; 65a9770eacSAndrew Lunn struct mdio_mux_parent_bus *pb = cb->parent; 66a9770eacSAndrew Lunn 67a9770eacSAndrew Lunn int r; 68a9770eacSAndrew Lunn 69a9770eacSAndrew Lunn mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX); 70a9770eacSAndrew Lunn r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data); 71a9770eacSAndrew Lunn if (r) 72a9770eacSAndrew Lunn goto out; 73a9770eacSAndrew Lunn 74a9770eacSAndrew Lunn pb->current_child = cb->bus_number; 75a9770eacSAndrew Lunn 76a9770eacSAndrew Lunn r = pb->mii_bus->write(pb->mii_bus, phy_id, regnum, val); 77a9770eacSAndrew Lunn out: 78a9770eacSAndrew Lunn mutex_unlock(&pb->mii_bus->mdio_lock); 79a9770eacSAndrew Lunn 80a9770eacSAndrew Lunn return r; 81a9770eacSAndrew Lunn } 82a9770eacSAndrew Lunn 83a9770eacSAndrew Lunn static int parent_count; 84a9770eacSAndrew Lunn 85a9770eacSAndrew Lunn int mdio_mux_init(struct device *dev, 86a9770eacSAndrew Lunn struct device_node *mux_node, 87a9770eacSAndrew Lunn int (*switch_fn)(int cur, int desired, void *data), 88a9770eacSAndrew Lunn void **mux_handle, 89a9770eacSAndrew Lunn void *data, 90a9770eacSAndrew Lunn struct mii_bus *mux_bus) 91a9770eacSAndrew Lunn { 92a9770eacSAndrew Lunn struct device_node *parent_bus_node; 93a9770eacSAndrew Lunn struct device_node *child_bus_node; 94a9770eacSAndrew Lunn int r, ret_val; 95a9770eacSAndrew Lunn struct mii_bus *parent_bus; 96a9770eacSAndrew Lunn struct mdio_mux_parent_bus *pb; 97a9770eacSAndrew Lunn struct mdio_mux_child_bus *cb; 98a9770eacSAndrew Lunn 99a9770eacSAndrew Lunn if (!mux_node) 100a9770eacSAndrew Lunn return -ENODEV; 101a9770eacSAndrew Lunn 102a9770eacSAndrew Lunn if (!mux_bus) { 103a9770eacSAndrew Lunn parent_bus_node = of_parse_phandle(mux_node, 104a9770eacSAndrew Lunn "mdio-parent-bus", 0); 105a9770eacSAndrew Lunn 106a9770eacSAndrew Lunn if (!parent_bus_node) 107a9770eacSAndrew Lunn return -ENODEV; 108a9770eacSAndrew Lunn 109a9770eacSAndrew Lunn parent_bus = of_mdio_find_bus(parent_bus_node); 110a9770eacSAndrew Lunn if (!parent_bus) { 111a9770eacSAndrew Lunn ret_val = -EPROBE_DEFER; 112a9770eacSAndrew Lunn goto err_parent_bus; 113a9770eacSAndrew Lunn } 114a9770eacSAndrew Lunn } else { 115a9770eacSAndrew Lunn parent_bus_node = NULL; 116a9770eacSAndrew Lunn parent_bus = mux_bus; 117a9770eacSAndrew Lunn get_device(&parent_bus->dev); 118a9770eacSAndrew Lunn } 119a9770eacSAndrew Lunn 120a9770eacSAndrew Lunn pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL); 121a9770eacSAndrew Lunn if (!pb) { 122a9770eacSAndrew Lunn ret_val = -ENOMEM; 123a9770eacSAndrew Lunn goto err_pb_kz; 124a9770eacSAndrew Lunn } 125a9770eacSAndrew Lunn 126a9770eacSAndrew Lunn pb->switch_data = data; 127a9770eacSAndrew Lunn pb->switch_fn = switch_fn; 128a9770eacSAndrew Lunn pb->current_child = -1; 129a9770eacSAndrew Lunn pb->parent_id = parent_count++; 130a9770eacSAndrew Lunn pb->mii_bus = parent_bus; 131a9770eacSAndrew Lunn 132a9770eacSAndrew Lunn ret_val = -ENODEV; 133a9770eacSAndrew Lunn for_each_available_child_of_node(mux_node, child_bus_node) { 134a9770eacSAndrew Lunn int v; 135a9770eacSAndrew Lunn 136a9770eacSAndrew Lunn r = of_property_read_u32(child_bus_node, "reg", &v); 137a9770eacSAndrew Lunn if (r) { 138a9770eacSAndrew Lunn dev_err(dev, 139a9770eacSAndrew Lunn "Error: Failed to find reg for child %pOF\n", 140a9770eacSAndrew Lunn child_bus_node); 141a9770eacSAndrew Lunn continue; 142a9770eacSAndrew Lunn } 143a9770eacSAndrew Lunn 144a9770eacSAndrew Lunn cb = devm_kzalloc(dev, sizeof(*cb), GFP_KERNEL); 145a9770eacSAndrew Lunn if (!cb) { 146a9770eacSAndrew Lunn ret_val = -ENOMEM; 147a9770eacSAndrew Lunn continue; 148a9770eacSAndrew Lunn } 149a9770eacSAndrew Lunn cb->bus_number = v; 150a9770eacSAndrew Lunn cb->parent = pb; 151a9770eacSAndrew Lunn 152a9770eacSAndrew Lunn cb->mii_bus = mdiobus_alloc(); 153a9770eacSAndrew Lunn if (!cb->mii_bus) { 154a9770eacSAndrew Lunn ret_val = -ENOMEM; 155a9770eacSAndrew Lunn devm_kfree(dev, cb); 156a9770eacSAndrew Lunn continue; 157a9770eacSAndrew Lunn } 158a9770eacSAndrew Lunn cb->mii_bus->priv = cb; 159a9770eacSAndrew Lunn 160a9770eacSAndrew Lunn cb->mii_bus->name = "mdio_mux"; 161a9770eacSAndrew Lunn snprintf(cb->mii_bus->id, MII_BUS_ID_SIZE, "%x.%x", 162a9770eacSAndrew Lunn pb->parent_id, v); 163a9770eacSAndrew Lunn cb->mii_bus->parent = dev; 164a9770eacSAndrew Lunn cb->mii_bus->read = mdio_mux_read; 165a9770eacSAndrew Lunn cb->mii_bus->write = mdio_mux_write; 166a9770eacSAndrew Lunn r = of_mdiobus_register(cb->mii_bus, child_bus_node); 167a9770eacSAndrew Lunn if (r) { 168a9770eacSAndrew Lunn dev_err(dev, 169a9770eacSAndrew Lunn "Error: Failed to register MDIO bus for child %pOF\n", 170a9770eacSAndrew Lunn child_bus_node); 171a9770eacSAndrew Lunn mdiobus_free(cb->mii_bus); 172a9770eacSAndrew Lunn devm_kfree(dev, cb); 173a9770eacSAndrew Lunn } else { 174a9770eacSAndrew Lunn cb->next = pb->children; 175a9770eacSAndrew Lunn pb->children = cb; 176a9770eacSAndrew Lunn } 177a9770eacSAndrew Lunn } 178a9770eacSAndrew Lunn if (pb->children) { 179a9770eacSAndrew Lunn *mux_handle = pb; 180a9770eacSAndrew Lunn return 0; 181a9770eacSAndrew Lunn } 182a9770eacSAndrew Lunn 183a9770eacSAndrew Lunn dev_err(dev, "Error: No acceptable child buses found\n"); 184a9770eacSAndrew Lunn devm_kfree(dev, pb); 185a9770eacSAndrew Lunn err_pb_kz: 186a9770eacSAndrew Lunn put_device(&parent_bus->dev); 187a9770eacSAndrew Lunn err_parent_bus: 188a9770eacSAndrew Lunn of_node_put(parent_bus_node); 189a9770eacSAndrew Lunn return ret_val; 190a9770eacSAndrew Lunn } 191a9770eacSAndrew Lunn EXPORT_SYMBOL_GPL(mdio_mux_init); 192a9770eacSAndrew Lunn 193a9770eacSAndrew Lunn void mdio_mux_uninit(void *mux_handle) 194a9770eacSAndrew Lunn { 195a9770eacSAndrew Lunn struct mdio_mux_parent_bus *pb = mux_handle; 196a9770eacSAndrew Lunn struct mdio_mux_child_bus *cb = pb->children; 197a9770eacSAndrew Lunn 198a9770eacSAndrew Lunn while (cb) { 199a9770eacSAndrew Lunn mdiobus_unregister(cb->mii_bus); 200a9770eacSAndrew Lunn mdiobus_free(cb->mii_bus); 201a9770eacSAndrew Lunn cb = cb->next; 202a9770eacSAndrew Lunn } 203a9770eacSAndrew Lunn 204a9770eacSAndrew Lunn put_device(&pb->mii_bus->dev); 205a9770eacSAndrew Lunn } 206a9770eacSAndrew Lunn EXPORT_SYMBOL_GPL(mdio_mux_uninit); 207a9770eacSAndrew Lunn 208a9770eacSAndrew Lunn MODULE_DESCRIPTION(DRV_DESCRIPTION); 209a9770eacSAndrew Lunn MODULE_AUTHOR("David Daney"); 210a9770eacSAndrew Lunn MODULE_LICENSE("GPL v2"); 211