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[thirdparty/kernel/linux.git] / drivers / usb / typec / bus.c
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1// SPDX-License-Identifier: GPL-2.0
2/**
3 * Bus for USB Type-C Alternate Modes
4 *
5 * Copyright (C) 2018 Intel Corporation
6 * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
7 */
8
9#include <linux/usb/pd_vdo.h>
10
11#include "bus.h"
12
13static inline int typec_altmode_set_mux(struct altmode *alt, u8 state)
14{
15 return alt->mux ? alt->mux->set(alt->mux, state) : 0;
16}
17
18static int typec_altmode_set_state(struct typec_altmode *adev, int state)
19{
20 bool is_port = is_typec_port(adev->dev.parent);
21 struct altmode *port_altmode;
22 int ret;
23
24 port_altmode = is_port ? to_altmode(adev) : to_altmode(adev)->partner;
25
26 ret = typec_altmode_set_mux(port_altmode, state);
27 if (ret)
28 return ret;
29
30 blocking_notifier_call_chain(&port_altmode->nh, state, NULL);
31
32 return 0;
33}
34
35/* -------------------------------------------------------------------------- */
36/* Common API */
37
38/**
39 * typec_altmode_notify - Communication between the OS and alternate mode driver
40 * @adev: Handle to the alternate mode
41 * @conf: Alternate mode specific configuration value
42 * @data: Alternate mode specific data
43 *
44 * The primary purpose for this function is to allow the alternate mode drivers
45 * to tell which pin configuration has been negotiated with the partner. That
46 * information will then be used for example to configure the muxes.
47 * Communication to the other direction is also possible, and low level device
48 * drivers can also send notifications to the alternate mode drivers. The actual
49 * communication will be specific for every SVID.
50 */
51int typec_altmode_notify(struct typec_altmode *adev,
52 unsigned long conf, void *data)
53{
9920184d 54 bool is_port;
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55 struct altmode *altmode;
56 struct altmode *partner;
57 int ret;
58
59 if (!adev)
60 return 0;
61
62 altmode = to_altmode(adev);
63
64 if (!altmode->partner)
65 return -ENODEV;
66
9920184d 67 is_port = is_typec_port(adev->dev.parent);
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68 partner = altmode->partner;
69
70 ret = typec_altmode_set_mux(is_port ? altmode : partner, (u8)conf);
71 if (ret)
72 return ret;
73
74 blocking_notifier_call_chain(is_port ? &altmode->nh : &partner->nh,
75 conf, data);
76
77 if (partner->adev.ops && partner->adev.ops->notify)
78 return partner->adev.ops->notify(&partner->adev, conf, data);
79
80 return 0;
81}
82EXPORT_SYMBOL_GPL(typec_altmode_notify);
83
84/**
85 * typec_altmode_enter - Enter Mode
86 * @adev: The alternate mode
87 *
88 * The alternate mode drivers use this function to enter mode. The port drivers
89 * use this to inform the alternate mode drivers that the partner has initiated
90 * Enter Mode command.
91 */
92int typec_altmode_enter(struct typec_altmode *adev)
93{
94 struct altmode *partner = to_altmode(adev)->partner;
95 struct typec_altmode *pdev = &partner->adev;
96 int ret;
97
98 if (!adev || adev->active)
99 return 0;
100
101 if (!pdev->ops || !pdev->ops->enter)
102 return -EOPNOTSUPP;
103
104 /* Moving to USB Safe State */
105 ret = typec_altmode_set_state(adev, TYPEC_STATE_SAFE);
106 if (ret)
107 return ret;
108
109 /* Enter Mode */
110 return pdev->ops->enter(pdev);
111}
112EXPORT_SYMBOL_GPL(typec_altmode_enter);
113
114/**
115 * typec_altmode_exit - Exit Mode
116 * @adev: The alternate mode
117 *
118 * The partner of @adev has initiated Exit Mode command.
119 */
120int typec_altmode_exit(struct typec_altmode *adev)
121{
122 struct altmode *partner = to_altmode(adev)->partner;
123 struct typec_altmode *pdev = &partner->adev;
124 int ret;
125
126 if (!adev || !adev->active)
127 return 0;
128
129 if (!pdev->ops || !pdev->ops->enter)
130 return -EOPNOTSUPP;
131
132 /* Moving to USB Safe State */
133 ret = typec_altmode_set_state(adev, TYPEC_STATE_SAFE);
134 if (ret)
135 return ret;
136
137 /* Exit Mode command */
138 return pdev->ops->exit(pdev);
139}
140EXPORT_SYMBOL_GPL(typec_altmode_exit);
141
142/**
143 * typec_altmode_attention - Attention command
144 * @adev: The alternate mode
145 * @vdo: VDO for the Attention command
146 *
147 * Notifies the partner of @adev about Attention command.
148 */
149void typec_altmode_attention(struct typec_altmode *adev, u32 vdo)
150{
151 struct typec_altmode *pdev = &to_altmode(adev)->partner->adev;
152
153 if (pdev->ops && pdev->ops->attention)
154 pdev->ops->attention(pdev, vdo);
155}
156EXPORT_SYMBOL_GPL(typec_altmode_attention);
157
158/**
159 * typec_altmode_vdm - Send Vendor Defined Messages (VDM) to the partner
160 * @adev: Alternate mode handle
161 * @header: VDM Header
162 * @vdo: Array of Vendor Defined Data Objects
163 * @count: Number of Data Objects
164 *
165 * The alternate mode drivers use this function for SVID specific communication
166 * with the partner. The port drivers use it to deliver the Structured VDMs
167 * received from the partners to the alternate mode drivers.
168 */
169int typec_altmode_vdm(struct typec_altmode *adev,
170 const u32 header, const u32 *vdo, int count)
171{
172 struct typec_altmode *pdev;
173 struct altmode *altmode;
174
175 if (!adev)
176 return 0;
177
178 altmode = to_altmode(adev);
179
180 if (!altmode->partner)
181 return -ENODEV;
182
183 pdev = &altmode->partner->adev;
184
185 if (!pdev->ops || !pdev->ops->vdm)
186 return -EOPNOTSUPP;
187
188 return pdev->ops->vdm(pdev, header, vdo, count);
189}
190EXPORT_SYMBOL_GPL(typec_altmode_vdm);
191
192const struct typec_altmode *
193typec_altmode_get_partner(struct typec_altmode *adev)
194{
195 return &to_altmode(adev)->partner->adev;
196}
197EXPORT_SYMBOL_GPL(typec_altmode_get_partner);
198
199/* -------------------------------------------------------------------------- */
200/* API for the alternate mode drivers */
201
202/**
203 * typec_altmode_get_plug - Find cable plug alternate mode
204 * @adev: Handle to partner alternate mode
205 * @index: Cable plug index
206 *
207 * Increment reference count for cable plug alternate mode device. Returns
208 * handle to the cable plug alternate mode, or NULL if none is found.
209 */
210struct typec_altmode *typec_altmode_get_plug(struct typec_altmode *adev,
211 enum typec_plug_index index)
212{
213 struct altmode *port = to_altmode(adev)->partner;
214
215 if (port->plug[index]) {
216 get_device(&port->plug[index]->adev.dev);
217 return &port->plug[index]->adev;
218 }
219
220 return NULL;
221}
222EXPORT_SYMBOL_GPL(typec_altmode_get_plug);
223
224/**
225 * typec_altmode_put_plug - Decrement cable plug alternate mode reference count
226 * @plug: Handle to the cable plug alternate mode
227 */
228void typec_altmode_put_plug(struct typec_altmode *plug)
229{
230 if (plug)
231 put_device(&plug->dev);
232}
233EXPORT_SYMBOL_GPL(typec_altmode_put_plug);
234
235int __typec_altmode_register_driver(struct typec_altmode_driver *drv,
236 struct module *module)
237{
238 if (!drv->probe)
239 return -EINVAL;
240
241 drv->driver.owner = module;
242 drv->driver.bus = &typec_bus;
243
244 return driver_register(&drv->driver);
245}
246EXPORT_SYMBOL_GPL(__typec_altmode_register_driver);
247
248void typec_altmode_unregister_driver(struct typec_altmode_driver *drv)
249{
250 driver_unregister(&drv->driver);
251}
252EXPORT_SYMBOL_GPL(typec_altmode_unregister_driver);
253
254/* -------------------------------------------------------------------------- */
255/* API for the port drivers */
256
257/**
258 * typec_match_altmode - Match SVID to an array of alternate modes
259 * @altmodes: Array of alternate modes
260 * @n: Number of elements in the array, or -1 for NULL termiated arrays
261 * @svid: Standard or Vendor ID to match with
262 *
263 * Return pointer to an alternate mode with SVID mathing @svid, or NULL when no
264 * match is found.
265 */
266struct typec_altmode *typec_match_altmode(struct typec_altmode **altmodes,
267 size_t n, u16 svid, u8 mode)
268{
269 int i;
270
271 for (i = 0; i < n; i++) {
272 if (!altmodes[i])
273 break;
274 if (altmodes[i]->svid == svid && altmodes[i]->mode == mode)
275 return altmodes[i];
276 }
277
278 return NULL;
279}
280EXPORT_SYMBOL_GPL(typec_match_altmode);
281
282/* -------------------------------------------------------------------------- */
283
284static ssize_t
285description_show(struct device *dev, struct device_attribute *attr, char *buf)
286{
287 struct typec_altmode *alt = to_typec_altmode(dev);
288
289 return sprintf(buf, "%s\n", alt->desc ? alt->desc : "");
290}
291static DEVICE_ATTR_RO(description);
292
293static struct attribute *typec_attrs[] = {
294 &dev_attr_description.attr,
295 NULL
296};
297ATTRIBUTE_GROUPS(typec);
298
299static int typec_match(struct device *dev, struct device_driver *driver)
300{
301 struct typec_altmode_driver *drv = to_altmode_driver(driver);
302 struct typec_altmode *altmode = to_typec_altmode(dev);
303 const struct typec_device_id *id;
304
305 for (id = drv->id_table; id->svid; id++)
306 if (id->svid == altmode->svid &&
307 (id->mode == TYPEC_ANY_MODE || id->mode == altmode->mode))
308 return 1;
309 return 0;
310}
311
312static int typec_uevent(struct device *dev, struct kobj_uevent_env *env)
313{
314 struct typec_altmode *altmode = to_typec_altmode(dev);
315
316 if (add_uevent_var(env, "SVID=%04X", altmode->svid))
317 return -ENOMEM;
318
319 if (add_uevent_var(env, "MODE=%u", altmode->mode))
320 return -ENOMEM;
321
322 return add_uevent_var(env, "MODALIAS=typec:id%04Xm%02X",
323 altmode->svid, altmode->mode);
324}
325
326static int typec_altmode_create_links(struct altmode *alt)
327{
328 struct device *port_dev = &alt->partner->adev.dev;
329 struct device *dev = &alt->adev.dev;
330 int err;
331
332 err = sysfs_create_link(&dev->kobj, &port_dev->kobj, "port");
333 if (err)
334 return err;
335
336 err = sysfs_create_link(&port_dev->kobj, &dev->kobj, "partner");
337 if (err)
338 sysfs_remove_link(&dev->kobj, "port");
339
340 return err;
341}
342
343static void typec_altmode_remove_links(struct altmode *alt)
344{
345 sysfs_remove_link(&alt->partner->adev.dev.kobj, "partner");
346 sysfs_remove_link(&alt->adev.dev.kobj, "port");
347}
348
349static int typec_probe(struct device *dev)
350{
351 struct typec_altmode_driver *drv = to_altmode_driver(dev->driver);
352 struct typec_altmode *adev = to_typec_altmode(dev);
353 struct altmode *altmode = to_altmode(adev);
354 int ret;
355
356 /* Fail if the port does not support the alternate mode */
357 if (!altmode->partner)
358 return -ENODEV;
359
360 ret = typec_altmode_create_links(altmode);
361 if (ret) {
362 dev_warn(dev, "failed to create symlinks\n");
363 return ret;
364 }
365
366 ret = drv->probe(adev);
367 if (ret)
368 typec_altmode_remove_links(altmode);
369
370 return ret;
371}
372
373static int typec_remove(struct device *dev)
374{
375 struct typec_altmode_driver *drv = to_altmode_driver(dev->driver);
376 struct typec_altmode *adev = to_typec_altmode(dev);
377 struct altmode *altmode = to_altmode(adev);
378
379 typec_altmode_remove_links(altmode);
380
381 if (drv->remove)
382 drv->remove(to_typec_altmode(dev));
383
384 if (adev->active) {
385 WARN_ON(typec_altmode_set_state(adev, TYPEC_STATE_SAFE));
386 typec_altmode_update_active(adev, false);
387 }
388
389 adev->desc = NULL;
390 adev->ops = NULL;
391
392 return 0;
393}
394
395struct bus_type typec_bus = {
396 .name = "typec",
397 .dev_groups = typec_groups,
398 .match = typec_match,
399 .uevent = typec_uevent,
400 .probe = typec_probe,
401 .remove = typec_remove,
402};