10ad63da5c
After the mii_bus API conversion to a split read() / read_c45(), there might be MDIO parent buses which only populate the read_c45() and write_c45() function pointers but not the C22 variants. We haven't seen these in the wild paired with MDIO multiplexers, but Andrew points out we should treat the corner case. Link: https://lore.kernel.org/netdev/4ccd7dc9-b611-48aa-865f-68d3a1327ce8@lunn.ch/ Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Link: https://lore.kernel.org/r/20231213152712.320842-3-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
271 lines
6.0 KiB
C
271 lines
6.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2011, 2012 Cavium, Inc.
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*/
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#include <linux/device.h>
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#include <linux/mdio-mux.h>
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#include <linux/module.h>
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#include <linux/of_mdio.h>
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#include <linux/phy.h>
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#include <linux/platform_device.h>
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#define DRV_DESCRIPTION "MDIO bus multiplexer driver"
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struct mdio_mux_child_bus;
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struct mdio_mux_parent_bus {
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struct mii_bus *mii_bus;
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int current_child;
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int parent_id;
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void *switch_data;
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int (*switch_fn)(int current_child, int desired_child, void *data);
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/* List of our children linked through their next fields. */
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struct mdio_mux_child_bus *children;
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};
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struct mdio_mux_child_bus {
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struct mii_bus *mii_bus;
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struct mdio_mux_parent_bus *parent;
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struct mdio_mux_child_bus *next;
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int bus_number;
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};
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/*
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* The parent bus' lock is used to order access to the switch_fn.
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*/
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static int mdio_mux_read(struct mii_bus *bus, int phy_id, int regnum)
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{
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struct mdio_mux_child_bus *cb = bus->priv;
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struct mdio_mux_parent_bus *pb = cb->parent;
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int r;
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mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX);
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r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
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if (r)
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goto out;
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pb->current_child = cb->bus_number;
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r = pb->mii_bus->read(pb->mii_bus, phy_id, regnum);
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out:
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mutex_unlock(&pb->mii_bus->mdio_lock);
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return r;
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}
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static int mdio_mux_read_c45(struct mii_bus *bus, int phy_id, int dev_addr,
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int regnum)
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{
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struct mdio_mux_child_bus *cb = bus->priv;
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struct mdio_mux_parent_bus *pb = cb->parent;
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int r;
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mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX);
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r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
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if (r)
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goto out;
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pb->current_child = cb->bus_number;
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r = pb->mii_bus->read_c45(pb->mii_bus, phy_id, dev_addr, regnum);
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out:
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mutex_unlock(&pb->mii_bus->mdio_lock);
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return r;
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}
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/*
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* The parent bus' lock is used to order access to the switch_fn.
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*/
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static int mdio_mux_write(struct mii_bus *bus, int phy_id,
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int regnum, u16 val)
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{
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struct mdio_mux_child_bus *cb = bus->priv;
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struct mdio_mux_parent_bus *pb = cb->parent;
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int r;
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mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX);
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r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
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if (r)
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goto out;
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pb->current_child = cb->bus_number;
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r = pb->mii_bus->write(pb->mii_bus, phy_id, regnum, val);
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out:
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mutex_unlock(&pb->mii_bus->mdio_lock);
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return r;
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}
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static int mdio_mux_write_c45(struct mii_bus *bus, int phy_id, int dev_addr,
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int regnum, u16 val)
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{
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struct mdio_mux_child_bus *cb = bus->priv;
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struct mdio_mux_parent_bus *pb = cb->parent;
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int r;
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mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX);
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r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
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if (r)
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goto out;
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pb->current_child = cb->bus_number;
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r = pb->mii_bus->write_c45(pb->mii_bus, phy_id, dev_addr, regnum, val);
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out:
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mutex_unlock(&pb->mii_bus->mdio_lock);
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return r;
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}
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static int parent_count;
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static void mdio_mux_uninit_children(struct mdio_mux_parent_bus *pb)
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{
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struct mdio_mux_child_bus *cb = pb->children;
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while (cb) {
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mdiobus_unregister(cb->mii_bus);
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mdiobus_free(cb->mii_bus);
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cb = cb->next;
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}
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}
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int mdio_mux_init(struct device *dev,
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struct device_node *mux_node,
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int (*switch_fn)(int cur, int desired, void *data),
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void **mux_handle,
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void *data,
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struct mii_bus *mux_bus)
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{
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struct device_node *parent_bus_node;
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struct device_node *child_bus_node;
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int r, ret_val;
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struct mii_bus *parent_bus;
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struct mdio_mux_parent_bus *pb;
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struct mdio_mux_child_bus *cb;
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if (!mux_node)
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return -ENODEV;
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if (!mux_bus) {
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parent_bus_node = of_parse_phandle(mux_node,
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"mdio-parent-bus", 0);
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if (!parent_bus_node)
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return -ENODEV;
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parent_bus = of_mdio_find_bus(parent_bus_node);
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if (!parent_bus) {
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ret_val = -EPROBE_DEFER;
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goto err_parent_bus;
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}
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} else {
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parent_bus_node = NULL;
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parent_bus = mux_bus;
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get_device(&parent_bus->dev);
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}
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pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL);
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if (!pb) {
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ret_val = -ENOMEM;
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goto err_pb_kz;
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}
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pb->switch_data = data;
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pb->switch_fn = switch_fn;
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pb->current_child = -1;
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pb->parent_id = parent_count++;
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pb->mii_bus = parent_bus;
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ret_val = -ENODEV;
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for_each_available_child_of_node(mux_node, child_bus_node) {
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int v;
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r = of_property_read_u32(child_bus_node, "reg", &v);
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if (r) {
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dev_err(dev,
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"Error: Failed to find reg for child %pOF: %pe\n",
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child_bus_node, ERR_PTR(r));
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continue;
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}
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cb = devm_kzalloc(dev, sizeof(*cb), GFP_KERNEL);
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if (!cb) {
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ret_val = -ENOMEM;
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goto err_loop;
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}
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cb->bus_number = v;
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cb->parent = pb;
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cb->mii_bus = mdiobus_alloc();
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if (!cb->mii_bus) {
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ret_val = -ENOMEM;
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goto err_loop;
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}
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cb->mii_bus->priv = cb;
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cb->mii_bus->name = "mdio_mux";
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snprintf(cb->mii_bus->id, MII_BUS_ID_SIZE, "%s-%x.%x",
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cb->mii_bus->name, pb->parent_id, v);
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cb->mii_bus->parent = dev;
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if (parent_bus->read)
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cb->mii_bus->read = mdio_mux_read;
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if (parent_bus->write)
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cb->mii_bus->write = mdio_mux_write;
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if (parent_bus->read_c45)
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cb->mii_bus->read_c45 = mdio_mux_read_c45;
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if (parent_bus->write_c45)
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cb->mii_bus->write_c45 = mdio_mux_write_c45;
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r = of_mdiobus_register(cb->mii_bus, child_bus_node);
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if (r) {
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mdiobus_free(cb->mii_bus);
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if (r == -EPROBE_DEFER) {
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ret_val = r;
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goto err_loop;
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}
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devm_kfree(dev, cb);
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dev_err(dev,
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"Error: Failed to register MDIO bus for child %pOF: %pe\n",
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child_bus_node, ERR_PTR(r));
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} else {
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cb->next = pb->children;
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pb->children = cb;
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}
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}
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if (pb->children) {
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*mux_handle = pb;
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return 0;
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}
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dev_err(dev, "Error: No acceptable child buses found\n");
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err_loop:
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mdio_mux_uninit_children(pb);
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of_node_put(child_bus_node);
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err_pb_kz:
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put_device(&parent_bus->dev);
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err_parent_bus:
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of_node_put(parent_bus_node);
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return ret_val;
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}
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EXPORT_SYMBOL_GPL(mdio_mux_init);
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void mdio_mux_uninit(void *mux_handle)
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{
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struct mdio_mux_parent_bus *pb = mux_handle;
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mdio_mux_uninit_children(pb);
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put_device(&pb->mii_bus->dev);
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}
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EXPORT_SYMBOL_GPL(mdio_mux_uninit);
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MODULE_DESCRIPTION(DRV_DESCRIPTION);
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MODULE_AUTHOR("David Daney");
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MODULE_LICENSE("GPL v2");
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