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210 lines
4.6 KiB
210 lines
4.6 KiB
// 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/platform_device.h> |
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#include <linux/mdio-mux.h> |
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#include <linux/of_mdio.h> |
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#include <linux/device.h> |
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#include <linux/module.h> |
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#include <linux/phy.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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/* |
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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 parent_count; |
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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\n", |
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child_bus_node); |
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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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continue; |
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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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devm_kfree(dev, cb); |
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continue; |
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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, "%x.%x", |
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pb->parent_id, v); |
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cb->mii_bus->parent = dev; |
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cb->mii_bus->read = mdio_mux_read; |
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cb->mii_bus->write = mdio_mux_write; |
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r = of_mdiobus_register(cb->mii_bus, child_bus_node); |
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if (r) { |
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dev_err(dev, |
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"Error: Failed to register MDIO bus for child %pOF\n", |
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child_bus_node); |
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mdiobus_free(cb->mii_bus); |
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devm_kfree(dev, cb); |
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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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devm_kfree(dev, pb); |
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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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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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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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