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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2022 Google LLC
*
* USB Type-C Retimer support.
* Author: Prashant Malani <pmalani@chromium.org>
*
*/
#include <linux/device.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/property.h>
#include <linux/slab.h>
#include "class.h"
#include "retimer.h"
static bool dev_name_ends_with(struct device *dev, const char *suffix)
{
const char *name = dev_name(dev);
const int name_len = strlen(name);
const int suffix_len = strlen(suffix);
if (suffix_len > name_len)
return false;
return strcmp(name + (name_len - suffix_len), suffix) == 0;
}
static int retimer_fwnode_match(struct device *dev, const void *fwnode)
{
return dev_fwnode(dev) == fwnode && dev_name_ends_with(dev, "-retimer");
}
static void *typec_retimer_match(struct fwnode_handle *fwnode, const char *id, void *data)
{
struct device *dev;
if (id && !fwnode_property_present(fwnode, id))
return NULL;
dev = class_find_device(&retimer_class, NULL, fwnode,
retimer_fwnode_match);
return dev ? to_typec_retimer(dev) : ERR_PTR(-EPROBE_DEFER);
}
/**
* fwnode_typec_retimer_get - Find USB Type-C retimer.
* @fwnode: The caller device node.
*
* Finds a retimer linked to the caller. This function is primarily meant for the
* Type-C drivers. Returns a reference to the retimer on success, NULL if no
* matching connection was found, or ERR_PTR(-EPROBE_DEFER) when a connection
* was found but the retimer has not been enumerated yet.
*/
struct typec_retimer *fwnode_typec_retimer_get(struct fwnode_handle *fwnode)
{
struct typec_retimer *retimer;
retimer = fwnode_connection_find_match(fwnode, "retimer-switch", NULL, typec_retimer_match);
if (!IS_ERR_OR_NULL(retimer))
WARN_ON(!try_module_get(retimer->dev.parent->driver->owner));
return retimer;
}
EXPORT_SYMBOL_GPL(fwnode_typec_retimer_get);
/**
* typec_retimer_put - Release handle to a retimer.
* @retimer: USB Type-C Connector Retimer.
*
* Decrements reference count for @retimer.
*/
void typec_retimer_put(struct typec_retimer *retimer)
{
if (!IS_ERR_OR_NULL(retimer)) {
module_put(retimer->dev.parent->driver->owner);
put_device(&retimer->dev);
}
}
EXPORT_SYMBOL_GPL(typec_retimer_put);
int typec_retimer_set(struct typec_retimer *retimer, struct typec_retimer_state *state)
{
if (IS_ERR_OR_NULL(retimer))
return 0;
return retimer->set(retimer, state);
}
EXPORT_SYMBOL_GPL(typec_retimer_set);
static void typec_retimer_release(struct device *dev)
{
kfree(to_typec_retimer(dev));
}
static const struct device_type typec_retimer_dev_type = {
.name = "typec_retimer",
.release = typec_retimer_release,
};
/**
* typec_retimer_register - Register a retimer device.
* @parent: Parent device.
* @desc: Retimer description.
*
* Some USB Type-C connectors have their physical lines routed through retimers before they
* reach muxes or host controllers. In some cases (for example: using alternate modes)
* these retimers need to be reconfigured appropriately. This function registers retimer
* switches which route and potentially modify the signals on the Type C physical lines
* enroute to the host controllers.
*/
struct typec_retimer *
typec_retimer_register(struct device *parent, const struct typec_retimer_desc *desc)
{
struct typec_retimer *retimer;
int ret;
if (!desc || !desc->set)
return ERR_PTR(-EINVAL);
retimer = kzalloc(sizeof(*retimer), GFP_KERNEL);
if (!retimer)
return ERR_PTR(-ENOMEM);
retimer->set = desc->set;
device_initialize(&retimer->dev);
retimer->dev.parent = parent;
retimer->dev.fwnode = desc->fwnode;
retimer->dev.class = &retimer_class;
retimer->dev.type = &typec_retimer_dev_type;
retimer->dev.driver_data = desc->drvdata;
dev_set_name(&retimer->dev, "%s-retimer",
desc->name ? desc->name : dev_name(parent));
ret = device_add(&retimer->dev);
if (ret) {
dev_err(parent, "failed to register retimer (%d)\n", ret);
put_device(&retimer->dev);
return ERR_PTR(ret);
}
return retimer;
}
EXPORT_SYMBOL_GPL(typec_retimer_register);
/**
* typec_retimer_unregister - Unregister retimer device.
* @retimer: USB Type-C Connector retimer.
*
* Unregister retimer that was registered with typec_retimer_register().
*/
void typec_retimer_unregister(struct typec_retimer *retimer)
{
if (!IS_ERR_OR_NULL(retimer))
device_unregister(&retimer->dev);
}
EXPORT_SYMBOL_GPL(typec_retimer_unregister);
void *typec_retimer_get_drvdata(struct typec_retimer *retimer)
{
return dev_get_drvdata(&retimer->dev);
}
EXPORT_SYMBOL_GPL(typec_retimer_get_drvdata);
struct class retimer_class = {
.name = "retimer",
.owner = THIS_MODULE,
};
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