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 | |
20 | static int retimer_fwnode_match(struct device *dev, const void *fwnode) |
21 | { |
22 | return is_typec_retimer(dev) && device_match_fwnode(dev, fwnode); |
23 | } |
24 | |
25 | static 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 | */ |
47 | struct 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 | } |
57 | EXPORT_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 | */ |
65 | void 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 | } |
72 | EXPORT_SYMBOL_GPL(typec_retimer_put); |
73 | |
74 | int 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 | } |
81 | EXPORT_SYMBOL_GPL(typec_retimer_set); |
82 | |
83 | static void typec_retimer_release(struct device *dev) |
84 | { |
85 | kfree(to_typec_retimer(dev)); |
86 | } |
87 | |
88 | const 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 | */ |
104 | struct typec_retimer * |
105 | typec_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(size: 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 | } |
137 | EXPORT_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 | */ |
145 | void typec_retimer_unregister(struct typec_retimer *retimer) |
146 | { |
147 | if (!IS_ERR_OR_NULL(ptr: retimer)) |
148 | device_unregister(dev: &retimer->dev); |
149 | } |
150 | EXPORT_SYMBOL_GPL(typec_retimer_unregister); |
151 | |
152 | void *typec_retimer_get_drvdata(struct typec_retimer *retimer) |
153 | { |
154 | return dev_get_drvdata(dev: &retimer->dev); |
155 | } |
156 | EXPORT_SYMBOL_GPL(typec_retimer_get_drvdata); |
157 | |
158 | const struct class retimer_class = { |
159 | .name = "retimer" , |
160 | }; |
161 | |