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// SPDX-License-Identifier: GPL-2.0
/**
* USB Type-C Multiplexer/DeMultiplexer Switch support
*
* Copyright (C) 2018 Intel Corporation
* Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
* Hans de Goede <hdegoede@redhat.com>
*/
#include <linux/device.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/usb/typec_mux.h>
static DEFINE_MUTEX(switch_lock);
static DEFINE_MUTEX(mux_lock);
static LIST_HEAD(switch_list);
static LIST_HEAD(mux_list);
static void *typec_switch_match(struct device_connection *con, int ep,
void *data)
{
struct typec_switch *sw;
list_for_each_entry(sw, &switch_list, entry)
if (!strcmp(con->endpoint[ep], dev_name(sw->dev)))
return sw;
/*
* We only get called if a connection was found, tell the caller to
* wait for the switch to show up.
*/
return ERR_PTR(-EPROBE_DEFER);
}
/**
* typec_switch_get - Find USB Type-C orientation switch
* @dev: The caller device
*
* Finds a switch linked with @dev. Returns a reference to the switch on
* success, NULL if no matching connection was found, or
* ERR_PTR(-EPROBE_DEFER) when a connection was found but the switch
* has not been enumerated yet.
*/
struct typec_switch *typec_switch_get(struct device *dev)
{
struct typec_switch *sw;
mutex_lock(&switch_lock);
sw = device_connection_find_match(dev, "typec-switch", NULL,
typec_switch_match);
if (!IS_ERR_OR_NULL(sw))
get_device(sw->dev);
mutex_unlock(&switch_lock);
return sw;
}
EXPORT_SYMBOL_GPL(typec_switch_get);
/**
* typec_put_switch - Release USB Type-C orientation switch
* @sw: USB Type-C orientation switch
*
* Decrement reference count for @sw.
*/
void typec_switch_put(struct typec_switch *sw)
{
if (!IS_ERR_OR_NULL(sw))
put_device(sw->dev);
}
EXPORT_SYMBOL_GPL(typec_switch_put);
/**
* typec_switch_register - Register USB Type-C orientation switch
* @sw: USB Type-C orientation switch
*
* This function registers a switch that can be used for routing the correct
* data pairs depending on the cable plug orientation from the USB Type-C
* connector to the USB controllers. USB Type-C plugs can be inserted
* right-side-up or upside-down.
*/
int typec_switch_register(struct typec_switch *sw)
{
mutex_lock(&switch_lock);
list_add_tail(&sw->entry, &switch_list);
mutex_unlock(&switch_lock);
return 0;
}
EXPORT_SYMBOL_GPL(typec_switch_register);
/**
* typec_switch_unregister - Unregister USB Type-C orientation switch
* @sw: USB Type-C orientation switch
*
* Unregister switch that was registered with typec_switch_register().
*/
void typec_switch_unregister(struct typec_switch *sw)
{
mutex_lock(&switch_lock);
list_del(&sw->entry);
mutex_unlock(&switch_lock);
}
EXPORT_SYMBOL_GPL(typec_switch_unregister);
/* ------------------------------------------------------------------------- */
static void *typec_mux_match(struct device_connection *con, int ep, void *data)
{
struct typec_mux *mux;
list_for_each_entry(mux, &mux_list, entry)
if (!strcmp(con->endpoint[ep], dev_name(mux->dev)))
return mux;
/*
* We only get called if a connection was found, tell the caller to
* wait for the switch to show up.
*/
return ERR_PTR(-EPROBE_DEFER);
}
/**
* typec_mux_get - Find USB Type-C Multiplexer
* @dev: The caller device
*
* Finds a mux linked to the caller. This function is primarily meant for the
* Type-C drivers. Returns a reference to the mux on success, NULL if no
* matching connection was found, or ERR_PTR(-EPROBE_DEFER) when a connection
* was found but the mux has not been enumerated yet.
*/
struct typec_mux *typec_mux_get(struct device *dev)
{
struct typec_mux *mux;
mutex_lock(&mux_lock);
mux = device_connection_find_match(dev, "typec-mux", NULL,
typec_mux_match);
if (!IS_ERR_OR_NULL(mux))
get_device(mux->dev);
mutex_unlock(&mux_lock);
return mux;
}
EXPORT_SYMBOL_GPL(typec_mux_get);
/**
* typec_mux_put - Release handle to a Multiplexer
* @mux: USB Type-C Connector Multiplexer/DeMultiplexer
*
* Decrements reference count for @mux.
*/
void typec_mux_put(struct typec_mux *mux)
{
if (!IS_ERR_OR_NULL(mux))
put_device(mux->dev);
}
EXPORT_SYMBOL_GPL(typec_mux_put);
/**
* typec_mux_register - Register Multiplexer routing USB Type-C pins
* @mux: USB Type-C Connector Multiplexer/DeMultiplexer
*
* USB Type-C connectors can be used for alternate modes of operation besides
* USB when Accessory/Alternate Modes are supported. With some of those modes,
* the pins on the connector need to be reconfigured. This function registers
* multiplexer switches routing the pins on the connector.
*/
int typec_mux_register(struct typec_mux *mux)
{
mutex_lock(&mux_lock);
list_add_tail(&mux->entry, &mux_list);
mutex_unlock(&mux_lock);
return 0;
}
EXPORT_SYMBOL_GPL(typec_mux_register);
/**
* typec_mux_unregister - Unregister Multiplexer Switch
* @sw: USB Type-C Connector Multiplexer/DeMultiplexer
*
* Unregister mux that was registered with typec_mux_register().
*/
void typec_mux_unregister(struct typec_mux *mux)
{
mutex_lock(&mux_lock);
list_del(&mux->entry);
mutex_unlock(&mux_lock);
}
EXPORT_SYMBOL_GPL(typec_mux_unregister);
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