1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright 2022 Google LLC
4 *
5 * USB Type-C Retimer support.
6 * Author: Prashant Malani <pmalani@chromium.org>
7 *
8 */
9
10#include <linux/device.h>
11#include <linux/list.h>
12#include <linux/module.h>
13#include <linux/mutex.h>
14#include <linux/property.h>
15#include <linux/slab.h>
16
17#include "class.h"
18#include "retimer.h"
19
20static int retimer_fwnode_match(struct device *dev, const void *fwnode)
21{
22 return is_typec_retimer(dev) && device_match_fwnode(dev, fwnode);
23}
24
25static void *typec_retimer_match(const struct fwnode_handle *fwnode, const char *id, void *data)
26{
27 struct device *dev;
28
29 if (id && !fwnode_property_present(fwnode, propname: id))
30 return NULL;
31
32 dev = class_find_device(class: &retimer_class, NULL, data: fwnode,
33 match: retimer_fwnode_match);
34
35 return dev ? to_typec_retimer(dev) : ERR_PTR(error: -EPROBE_DEFER);
36}
37
38/**
39 * fwnode_typec_retimer_get - Find USB Type-C retimer.
40 * @fwnode: The caller device node.
41 *
42 * Finds a retimer linked to the caller. This function is primarily meant for the
43 * Type-C drivers. Returns a reference to the retimer on success, NULL if no
44 * matching connection was found, or ERR_PTR(-EPROBE_DEFER) when a connection
45 * was found but the retimer has not been enumerated yet.
46 */
47struct typec_retimer *fwnode_typec_retimer_get(struct fwnode_handle *fwnode)
48{
49 struct typec_retimer *retimer;
50
51 retimer = fwnode_connection_find_match(fwnode, con_id: "retimer-switch", NULL, match: typec_retimer_match);
52 if (!IS_ERR_OR_NULL(ptr: retimer))
53 WARN_ON(!try_module_get(retimer->dev.parent->driver->owner));
54
55 return retimer;
56}
57EXPORT_SYMBOL_GPL(fwnode_typec_retimer_get);
58
59/**
60 * typec_retimer_put - Release handle to a retimer.
61 * @retimer: USB Type-C Connector Retimer.
62 *
63 * Decrements reference count for @retimer.
64 */
65void typec_retimer_put(struct typec_retimer *retimer)
66{
67 if (!IS_ERR_OR_NULL(ptr: retimer)) {
68 module_put(module: retimer->dev.parent->driver->owner);
69 put_device(dev: &retimer->dev);
70 }
71}
72EXPORT_SYMBOL_GPL(typec_retimer_put);
73
74int typec_retimer_set(struct typec_retimer *retimer, struct typec_retimer_state *state)
75{
76 if (IS_ERR_OR_NULL(ptr: retimer))
77 return 0;
78
79 return retimer->set(retimer, state);
80}
81EXPORT_SYMBOL_GPL(typec_retimer_set);
82
83static void typec_retimer_release(struct device *dev)
84{
85 kfree(to_typec_retimer(dev));
86}
87
88const struct device_type typec_retimer_dev_type = {
89 .name = "typec_retimer",
90 .release = typec_retimer_release,
91};
92
93/**
94 * typec_retimer_register - Register a retimer device.
95 * @parent: Parent device.
96 * @desc: Retimer description.
97 *
98 * Some USB Type-C connectors have their physical lines routed through retimers before they
99 * reach muxes or host controllers. In some cases (for example: using alternate modes)
100 * these retimers need to be reconfigured appropriately. This function registers retimer
101 * switches which route and potentially modify the signals on the Type C physical lines
102 * enroute to the host controllers.
103 */
104struct typec_retimer *
105typec_retimer_register(struct device *parent, const struct typec_retimer_desc *desc)
106{
107 struct typec_retimer *retimer;
108 int ret;
109
110 if (!desc || !desc->set)
111 return ERR_PTR(error: -EINVAL);
112
113 retimer = kzalloc(sizeof(*retimer), GFP_KERNEL);
114 if (!retimer)
115 return ERR_PTR(error: -ENOMEM);
116
117 retimer->set = desc->set;
118
119 device_initialize(dev: &retimer->dev);
120 retimer->dev.parent = parent;
121 retimer->dev.fwnode = desc->fwnode;
122 retimer->dev.class = &retimer_class;
123 retimer->dev.type = &typec_retimer_dev_type;
124 retimer->dev.driver_data = desc->drvdata;
125 dev_set_name(dev: &retimer->dev, name: "%s-retimer",
126 desc->name ? desc->name : dev_name(dev: parent));
127
128 ret = device_add(dev: &retimer->dev);
129 if (ret) {
130 dev_err(parent, "failed to register retimer (%d)\n", ret);
131 put_device(dev: &retimer->dev);
132 return ERR_PTR(error: ret);
133 }
134
135 return retimer;
136}
137EXPORT_SYMBOL_GPL(typec_retimer_register);
138
139/**
140 * typec_retimer_unregister - Unregister retimer device.
141 * @retimer: USB Type-C Connector retimer.
142 *
143 * Unregister retimer that was registered with typec_retimer_register().
144 */
145void typec_retimer_unregister(struct typec_retimer *retimer)
146{
147 if (!IS_ERR_OR_NULL(ptr: retimer))
148 device_unregister(dev: &retimer->dev);
149}
150EXPORT_SYMBOL_GPL(typec_retimer_unregister);
151
152void *typec_retimer_get_drvdata(struct typec_retimer *retimer)
153{
154 return dev_get_drvdata(dev: &retimer->dev);
155}
156EXPORT_SYMBOL_GPL(typec_retimer_get_drvdata);
157
158const struct class retimer_class = {
159 .name = "retimer",
160};
161

source code of linux/drivers/usb/typec/retimer.c