1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright 2022 Google LLC
5 * USB Type-C Retimer support.
6 * Author: Prashant Malani <pmalani@chromium.org>
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>
20 static bool dev_name_ends_with(struct device *dev, const char *suffix)
22 const char *name = dev_name(dev);
23 const int name_len = strlen(name);
24 const int suffix_len = strlen(suffix);
26 if (suffix_len > name_len)
29 return strcmp(name + (name_len - suffix_len), suffix) == 0;
32 static int retimer_fwnode_match(struct device *dev, const void *fwnode)
34 return dev_fwnode(dev) == fwnode && dev_name_ends_with(dev, "-retimer");
37 static void *typec_retimer_match(struct fwnode_handle *fwnode, const char *id, void *data)
39 struct device *dev = class_find_device(&retimer_class, NULL, fwnode,
40 retimer_fwnode_match);
42 return dev ? to_typec_retimer(dev) : ERR_PTR(-EPROBE_DEFER);
46 * fwnode_typec_retimer_get - Find USB Type-C retimer.
47 * @fwnode: The caller device node.
49 * Finds a retimer linked to the caller. This function is primarily meant for the
50 * Type-C drivers. Returns a reference to the retimer on success, NULL if no
51 * matching connection was found, or ERR_PTR(-EPROBE_DEFER) when a connection
52 * was found but the retimer has not been enumerated yet.
54 struct typec_retimer *fwnode_typec_retimer_get(struct fwnode_handle *fwnode)
56 struct typec_retimer *retimer;
58 retimer = fwnode_connection_find_match(fwnode, "retimer-switch", NULL, typec_retimer_match);
59 if (!IS_ERR_OR_NULL(retimer))
60 WARN_ON(!try_module_get(retimer->dev.parent->driver->owner));
64 EXPORT_SYMBOL_GPL(fwnode_typec_retimer_get);
67 * typec_retimer_put - Release handle to a retimer.
68 * @retimer: USB Type-C Connector Retimer.
70 * Decrements reference count for @retimer.
72 void typec_retimer_put(struct typec_retimer *retimer)
74 if (!IS_ERR_OR_NULL(retimer)) {
75 module_put(retimer->dev.parent->driver->owner);
76 put_device(&retimer->dev);
79 EXPORT_SYMBOL_GPL(typec_retimer_put);
81 int typec_retimer_set(struct typec_retimer *retimer, struct typec_retimer_state *state)
83 if (IS_ERR_OR_NULL(retimer))
86 return retimer->set(retimer, state);
88 EXPORT_SYMBOL_GPL(typec_retimer_set);
90 static void typec_retimer_release(struct device *dev)
92 kfree(to_typec_retimer(dev));
95 static const struct device_type typec_retimer_dev_type = {
96 .name = "typec_retimer",
97 .release = typec_retimer_release,
101 * typec_retimer_register - Register a retimer device.
102 * @parent: Parent device.
103 * @desc: Retimer description.
105 * Some USB Type-C connectors have their physical lines routed through retimers before they
106 * reach muxes or host controllers. In some cases (for example: using alternate modes)
107 * these retimers need to be reconfigured appropriately. This function registers retimer
108 * switches which route and potentially modify the signals on the Type C physical lines
109 * enroute to the host controllers.
111 struct typec_retimer *
112 typec_retimer_register(struct device *parent, const struct typec_retimer_desc *desc)
114 struct typec_retimer *retimer;
117 if (!desc || !desc->set)
118 return ERR_PTR(-EINVAL);
120 retimer = kzalloc(sizeof(*retimer), GFP_KERNEL);
122 return ERR_PTR(-ENOMEM);
124 retimer->set = desc->set;
126 device_initialize(&retimer->dev);
127 retimer->dev.parent = parent;
128 retimer->dev.fwnode = desc->fwnode;
129 retimer->dev.class = &retimer_class;
130 retimer->dev.type = &typec_retimer_dev_type;
131 retimer->dev.driver_data = desc->drvdata;
132 dev_set_name(&retimer->dev, "%s-retimer",
133 desc->name ? desc->name : dev_name(parent));
135 ret = device_add(&retimer->dev);
137 dev_err(parent, "failed to register retimer (%d)\n", ret);
138 put_device(&retimer->dev);
144 EXPORT_SYMBOL_GPL(typec_retimer_register);
147 * typec_retimer_unregister - Unregister retimer device.
148 * @retimer: USB Type-C Connector retimer.
150 * Unregister retimer that was registered with typec_retimer_register().
152 void typec_retimer_unregister(struct typec_retimer *retimer)
154 if (!IS_ERR_OR_NULL(retimer))
155 device_unregister(&retimer->dev);
157 EXPORT_SYMBOL_GPL(typec_retimer_unregister);
159 void *typec_retimer_get_drvdata(struct typec_retimer *retimer)
161 return dev_get_drvdata(&retimer->dev);
163 EXPORT_SYMBOL_GPL(typec_retimer_get_drvdata);
165 struct class retimer_class = {
167 .owner = THIS_MODULE,