xref: /openbmc/linux/drivers/usb/typec/pd.c (revision 6c8c1406)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * USB Power Delivery sysfs entries
4  *
5  * Copyright (C) 2022, Intel Corporation
6  * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
7  */
8 
9 #include <linux/slab.h>
10 #include <linux/usb/pd.h>
11 
12 #include "pd.h"
13 
14 static DEFINE_IDA(pd_ida);
15 
16 static struct class pd_class = {
17 	.name = "usb_power_delivery",
18 	.owner = THIS_MODULE,
19 };
20 
21 #define to_pdo(o) container_of(o, struct pdo, dev)
22 
23 struct pdo {
24 	struct device dev;
25 	int object_position;
26 	u32 pdo;
27 };
28 
29 static void pdo_release(struct device *dev)
30 {
31 	kfree(to_pdo(dev));
32 }
33 
34 /* -------------------------------------------------------------------------- */
35 /* Fixed Supply */
36 
37 static ssize_t
38 dual_role_power_show(struct device *dev, struct device_attribute *attr, char *buf)
39 {
40 	return sysfs_emit(buf, "%u\n", !!(to_pdo(dev)->pdo & PDO_FIXED_DUAL_ROLE));
41 }
42 static DEVICE_ATTR_RO(dual_role_power);
43 
44 static ssize_t
45 usb_suspend_supported_show(struct device *dev, struct device_attribute *attr, char *buf)
46 {
47 	return sysfs_emit(buf, "%u\n", !!(to_pdo(dev)->pdo & PDO_FIXED_SUSPEND));
48 }
49 static DEVICE_ATTR_RO(usb_suspend_supported);
50 
51 static ssize_t
52 unconstrained_power_show(struct device *dev, struct device_attribute *attr, char *buf)
53 {
54 	return sysfs_emit(buf, "%u\n", !!(to_pdo(dev)->pdo & PDO_FIXED_EXTPOWER));
55 }
56 static DEVICE_ATTR_RO(unconstrained_power);
57 
58 static ssize_t
59 usb_communication_capable_show(struct device *dev, struct device_attribute *attr, char *buf)
60 {
61 	return sysfs_emit(buf, "%u\n", !!(to_pdo(dev)->pdo & PDO_FIXED_USB_COMM));
62 }
63 static DEVICE_ATTR_RO(usb_communication_capable);
64 
65 static ssize_t
66 dual_role_data_show(struct device *dev, struct device_attribute *attr, char *buf)
67 {
68 	return sysfs_emit(buf, "%u\n", !!(to_pdo(dev)->pdo & PDO_FIXED_DATA_SWAP));
69 }
70 static DEVICE_ATTR_RO(dual_role_data);
71 
72 static ssize_t
73 unchunked_extended_messages_supported_show(struct device *dev,
74 					   struct device_attribute *attr, char *buf)
75 {
76 	return sysfs_emit(buf, "%u\n", !!(to_pdo(dev)->pdo & PDO_FIXED_UNCHUNK_EXT));
77 }
78 static DEVICE_ATTR_RO(unchunked_extended_messages_supported);
79 
80 /*
81  * REVISIT: Peak Current requires access also to the RDO.
82 static ssize_t
83 peak_current_show(struct device *dev, struct device_attribute *attr, char *buf)
84 {
85 	...
86 }
87 */
88 
89 static ssize_t
90 fast_role_swap_current_show(struct device *dev, struct device_attribute *attr, char *buf)
91 {
92 	return sysfs_emit(buf, "%u\n", to_pdo(dev)->pdo >> PDO_FIXED_FRS_CURR_SHIFT) & 3;
93 }
94 static DEVICE_ATTR_RO(fast_role_swap_current);
95 
96 static ssize_t voltage_show(struct device *dev, struct device_attribute *attr, char *buf)
97 {
98 	return sysfs_emit(buf, "%umV\n", pdo_fixed_voltage(to_pdo(dev)->pdo));
99 }
100 static DEVICE_ATTR_RO(voltage);
101 
102 /* Shared with Variable supplies, both source and sink */
103 static ssize_t current_show(struct device *dev, struct device_attribute *attr, char *buf)
104 {
105 	return sysfs_emit(buf, "%umA\n", pdo_max_current(to_pdo(dev)->pdo));
106 }
107 
108 /* Shared with Variable type supplies */
109 static struct device_attribute maximum_current_attr = {
110 	.attr = {
111 		.name = "maximum_current",
112 		.mode = 0444,
113 	},
114 	.show = current_show,
115 };
116 
117 static struct device_attribute operational_current_attr = {
118 	.attr = {
119 		.name = "operational_current",
120 		.mode = 0444,
121 	},
122 	.show = current_show,
123 };
124 
125 static struct attribute *source_fixed_supply_attrs[] = {
126 	&dev_attr_dual_role_power.attr,
127 	&dev_attr_usb_suspend_supported.attr,
128 	&dev_attr_unconstrained_power.attr,
129 	&dev_attr_usb_communication_capable.attr,
130 	&dev_attr_dual_role_data.attr,
131 	&dev_attr_unchunked_extended_messages_supported.attr,
132 	/*&dev_attr_peak_current.attr,*/
133 	&dev_attr_voltage.attr,
134 	&maximum_current_attr.attr,
135 	NULL
136 };
137 
138 static umode_t fixed_attr_is_visible(struct kobject *kobj, struct attribute *attr, int n)
139 {
140 	if (to_pdo(kobj_to_dev(kobj))->object_position &&
141 	    /*attr != &dev_attr_peak_current.attr &&*/
142 	    attr != &dev_attr_voltage.attr &&
143 	    attr != &maximum_current_attr.attr &&
144 	    attr != &operational_current_attr.attr)
145 		return 0;
146 
147 	return attr->mode;
148 }
149 
150 static const struct attribute_group source_fixed_supply_group = {
151 	.is_visible = fixed_attr_is_visible,
152 	.attrs = source_fixed_supply_attrs,
153 };
154 __ATTRIBUTE_GROUPS(source_fixed_supply);
155 
156 static struct device_type source_fixed_supply_type = {
157 	.name = "pdo",
158 	.release = pdo_release,
159 	.groups = source_fixed_supply_groups,
160 };
161 
162 static struct attribute *sink_fixed_supply_attrs[] = {
163 	&dev_attr_dual_role_power.attr,
164 	&dev_attr_usb_suspend_supported.attr,
165 	&dev_attr_unconstrained_power.attr,
166 	&dev_attr_usb_communication_capable.attr,
167 	&dev_attr_dual_role_data.attr,
168 	&dev_attr_unchunked_extended_messages_supported.attr,
169 	&dev_attr_fast_role_swap_current.attr,
170 	&dev_attr_voltage.attr,
171 	&operational_current_attr.attr,
172 	NULL
173 };
174 
175 static const struct attribute_group sink_fixed_supply_group = {
176 	.is_visible = fixed_attr_is_visible,
177 	.attrs = sink_fixed_supply_attrs,
178 };
179 __ATTRIBUTE_GROUPS(sink_fixed_supply);
180 
181 static struct device_type sink_fixed_supply_type = {
182 	.name = "pdo",
183 	.release = pdo_release,
184 	.groups = sink_fixed_supply_groups,
185 };
186 
187 /* -------------------------------------------------------------------------- */
188 /* Variable Supply */
189 
190 static ssize_t
191 maximum_voltage_show(struct device *dev, struct device_attribute *attr, char *buf)
192 {
193 	return sysfs_emit(buf, "%umV\n", pdo_max_voltage(to_pdo(dev)->pdo));
194 }
195 static DEVICE_ATTR_RO(maximum_voltage);
196 
197 static ssize_t
198 minimum_voltage_show(struct device *dev, struct device_attribute *attr, char *buf)
199 {
200 	return sysfs_emit(buf, "%umV\n", pdo_min_voltage(to_pdo(dev)->pdo));
201 }
202 static DEVICE_ATTR_RO(minimum_voltage);
203 
204 static struct attribute *source_variable_supply_attrs[] = {
205 	&dev_attr_maximum_voltage.attr,
206 	&dev_attr_minimum_voltage.attr,
207 	&maximum_current_attr.attr,
208 	NULL
209 };
210 ATTRIBUTE_GROUPS(source_variable_supply);
211 
212 static struct device_type source_variable_supply_type = {
213 	.name = "pdo",
214 	.release = pdo_release,
215 	.groups = source_variable_supply_groups,
216 };
217 
218 static struct attribute *sink_variable_supply_attrs[] = {
219 	&dev_attr_maximum_voltage.attr,
220 	&dev_attr_minimum_voltage.attr,
221 	&operational_current_attr.attr,
222 	NULL
223 };
224 ATTRIBUTE_GROUPS(sink_variable_supply);
225 
226 static struct device_type sink_variable_supply_type = {
227 	.name = "pdo",
228 	.release = pdo_release,
229 	.groups = sink_variable_supply_groups,
230 };
231 
232 /* -------------------------------------------------------------------------- */
233 /* Battery */
234 
235 static ssize_t
236 maximum_power_show(struct device *dev, struct device_attribute *attr, char *buf)
237 {
238 	return sysfs_emit(buf, "%umW\n", pdo_max_power(to_pdo(dev)->pdo));
239 }
240 static DEVICE_ATTR_RO(maximum_power);
241 
242 static ssize_t
243 operational_power_show(struct device *dev, struct device_attribute *attr, char *buf)
244 {
245 	return sysfs_emit(buf, "%umW\n", pdo_max_power(to_pdo(dev)->pdo));
246 }
247 static DEVICE_ATTR_RO(operational_power);
248 
249 static struct attribute *source_battery_attrs[] = {
250 	&dev_attr_maximum_voltage.attr,
251 	&dev_attr_minimum_voltage.attr,
252 	&dev_attr_maximum_power.attr,
253 	NULL
254 };
255 ATTRIBUTE_GROUPS(source_battery);
256 
257 static struct device_type source_battery_type = {
258 	.name = "pdo",
259 	.release = pdo_release,
260 	.groups = source_battery_groups,
261 };
262 
263 static struct attribute *sink_battery_attrs[] = {
264 	&dev_attr_maximum_voltage.attr,
265 	&dev_attr_minimum_voltage.attr,
266 	&dev_attr_operational_power.attr,
267 	NULL
268 };
269 ATTRIBUTE_GROUPS(sink_battery);
270 
271 static struct device_type sink_battery_type = {
272 	.name = "pdo",
273 	.release = pdo_release,
274 	.groups = sink_battery_groups,
275 };
276 
277 /* -------------------------------------------------------------------------- */
278 /* Standard Power Range (SPR) Programmable Power Supply (PPS) */
279 
280 static ssize_t
281 pps_power_limited_show(struct device *dev, struct device_attribute *attr, char *buf)
282 {
283 	return sysfs_emit(buf, "%u\n", !!(to_pdo(dev)->pdo & BIT(27)));
284 }
285 static DEVICE_ATTR_RO(pps_power_limited);
286 
287 static ssize_t
288 pps_max_voltage_show(struct device *dev, struct device_attribute *attr, char *buf)
289 {
290 	return sysfs_emit(buf, "%umV\n", pdo_pps_apdo_max_voltage(to_pdo(dev)->pdo));
291 }
292 
293 static ssize_t
294 pps_min_voltage_show(struct device *dev, struct device_attribute *attr, char *buf)
295 {
296 	return sysfs_emit(buf, "%umV\n", pdo_pps_apdo_min_voltage(to_pdo(dev)->pdo));
297 }
298 
299 static ssize_t
300 pps_max_current_show(struct device *dev, struct device_attribute *attr, char *buf)
301 {
302 	return sysfs_emit(buf, "%umA\n", pdo_pps_apdo_max_current(to_pdo(dev)->pdo));
303 }
304 
305 static struct device_attribute pps_max_voltage_attr = {
306 	.attr = {
307 		.name = "maximum_voltage",
308 		.mode = 0444,
309 	},
310 	.show = pps_max_voltage_show,
311 };
312 
313 static struct device_attribute pps_min_voltage_attr = {
314 	.attr = {
315 		.name = "minimum_voltage",
316 		.mode = 0444,
317 	},
318 	.show = pps_min_voltage_show,
319 };
320 
321 static struct device_attribute pps_max_current_attr = {
322 	.attr = {
323 		.name = "maximum_current",
324 		.mode = 0444,
325 	},
326 	.show = pps_max_current_show,
327 };
328 
329 static struct attribute *source_pps_attrs[] = {
330 	&dev_attr_pps_power_limited.attr,
331 	&pps_max_voltage_attr.attr,
332 	&pps_min_voltage_attr.attr,
333 	&pps_max_current_attr.attr,
334 	NULL
335 };
336 ATTRIBUTE_GROUPS(source_pps);
337 
338 static struct device_type source_pps_type = {
339 	.name = "pdo",
340 	.release = pdo_release,
341 	.groups = source_pps_groups,
342 };
343 
344 static struct attribute *sink_pps_attrs[] = {
345 	&pps_max_voltage_attr.attr,
346 	&pps_min_voltage_attr.attr,
347 	&pps_max_current_attr.attr,
348 	NULL
349 };
350 ATTRIBUTE_GROUPS(sink_pps);
351 
352 static struct device_type sink_pps_type = {
353 	.name = "pdo",
354 	.release = pdo_release,
355 	.groups = sink_pps_groups,
356 };
357 
358 /* -------------------------------------------------------------------------- */
359 
360 static const char * const supply_name[] = {
361 	[PDO_TYPE_FIXED] = "fixed_supply",
362 	[PDO_TYPE_BATT]  = "battery",
363 	[PDO_TYPE_VAR]	 = "variable_supply",
364 };
365 
366 static const char * const apdo_supply_name[] = {
367 	[APDO_TYPE_PPS]  = "programmable_supply",
368 };
369 
370 static struct device_type *source_type[] = {
371 	[PDO_TYPE_FIXED] = &source_fixed_supply_type,
372 	[PDO_TYPE_BATT]  = &source_battery_type,
373 	[PDO_TYPE_VAR]   = &source_variable_supply_type,
374 };
375 
376 static struct device_type *source_apdo_type[] = {
377 	[APDO_TYPE_PPS]  = &source_pps_type,
378 };
379 
380 static struct device_type *sink_type[] = {
381 	[PDO_TYPE_FIXED] = &sink_fixed_supply_type,
382 	[PDO_TYPE_BATT]  = &sink_battery_type,
383 	[PDO_TYPE_VAR]   = &sink_variable_supply_type,
384 };
385 
386 static struct device_type *sink_apdo_type[] = {
387 	[APDO_TYPE_PPS]  = &sink_pps_type,
388 };
389 
390 /* REVISIT: Export when EPR_*_Capabilities need to be supported. */
391 static int add_pdo(struct usb_power_delivery_capabilities *cap, u32 pdo, int position)
392 {
393 	struct device_type *type;
394 	const char *name;
395 	struct pdo *p;
396 	int ret;
397 
398 	p = kzalloc(sizeof(*p), GFP_KERNEL);
399 	if (!p)
400 		return -ENOMEM;
401 
402 	p->pdo = pdo;
403 	p->object_position = position;
404 
405 	if (pdo_type(pdo) == PDO_TYPE_APDO) {
406 		/* FIXME: Only PPS supported for now! Skipping others. */
407 		if (pdo_apdo_type(pdo) > APDO_TYPE_PPS) {
408 			dev_warn(&cap->dev, "Unknown APDO type. PDO 0x%08x\n", pdo);
409 			kfree(p);
410 			return 0;
411 		}
412 
413 		if (is_source(cap->role))
414 			type = source_apdo_type[pdo_apdo_type(pdo)];
415 		else
416 			type = sink_apdo_type[pdo_apdo_type(pdo)];
417 
418 		name = apdo_supply_name[pdo_apdo_type(pdo)];
419 	} else {
420 		if (is_source(cap->role))
421 			type = source_type[pdo_type(pdo)];
422 		else
423 			type = sink_type[pdo_type(pdo)];
424 
425 		name = supply_name[pdo_type(pdo)];
426 	}
427 
428 	p->dev.parent = &cap->dev;
429 	p->dev.type = type;
430 	dev_set_name(&p->dev, "%u:%s", position + 1, name);
431 
432 	ret = device_register(&p->dev);
433 	if (ret) {
434 		put_device(&p->dev);
435 		return ret;
436 	}
437 
438 	return 0;
439 }
440 
441 static int remove_pdo(struct device *dev, void *data)
442 {
443 	device_unregister(dev);
444 	return 0;
445 }
446 
447 /* -------------------------------------------------------------------------- */
448 
449 static const char * const cap_name[] = {
450 	[TYPEC_SINK]    = "sink-capabilities",
451 	[TYPEC_SOURCE]  = "source-capabilities",
452 };
453 
454 static void pd_capabilities_release(struct device *dev)
455 {
456 	kfree(to_usb_power_delivery_capabilities(dev));
457 }
458 
459 static struct device_type pd_capabilities_type = {
460 	.name = "capabilities",
461 	.release = pd_capabilities_release,
462 };
463 
464 /**
465  * usb_power_delivery_register_capabilities - Register a set of capabilities.
466  * @pd: The USB PD instance that the capabilities belong to.
467  * @desc: Description of the Capablities Message.
468  *
469  * This function registers a Capabilities Message described in @desc. The
470  * capabilities will have their own sub-directory under @pd in sysfs.
471  *
472  * The function returns pointer to struct usb_power_delivery_capabilities, or
473  * ERR_PRT(errno).
474  */
475 struct usb_power_delivery_capabilities *
476 usb_power_delivery_register_capabilities(struct usb_power_delivery *pd,
477 					 struct usb_power_delivery_capabilities_desc *desc)
478 {
479 	struct usb_power_delivery_capabilities *cap;
480 	int ret;
481 	int i;
482 
483 	cap = kzalloc(sizeof(*cap), GFP_KERNEL);
484 	if (!cap)
485 		return ERR_PTR(-ENOMEM);
486 
487 	cap->pd = pd;
488 	cap->role = desc->role;
489 
490 	cap->dev.parent = &pd->dev;
491 	cap->dev.type = &pd_capabilities_type;
492 	dev_set_name(&cap->dev, "%s", cap_name[cap->role]);
493 
494 	ret = device_register(&cap->dev);
495 	if (ret) {
496 		put_device(&cap->dev);
497 		return ERR_PTR(ret);
498 	}
499 
500 	for (i = 0; i < PDO_MAX_OBJECTS && desc->pdo[i]; i++) {
501 		ret = add_pdo(cap, desc->pdo[i], i);
502 		if (ret) {
503 			usb_power_delivery_unregister_capabilities(cap);
504 			return ERR_PTR(ret);
505 		}
506 	}
507 
508 	return cap;
509 }
510 EXPORT_SYMBOL_GPL(usb_power_delivery_register_capabilities);
511 
512 /**
513  * usb_power_delivery_unregister_capabilities - Unregister a set of capabilities
514  * @cap: The capabilities
515  */
516 void usb_power_delivery_unregister_capabilities(struct usb_power_delivery_capabilities *cap)
517 {
518 	if (!cap)
519 		return;
520 
521 	device_for_each_child(&cap->dev, NULL, remove_pdo);
522 	device_unregister(&cap->dev);
523 }
524 EXPORT_SYMBOL_GPL(usb_power_delivery_unregister_capabilities);
525 
526 /* -------------------------------------------------------------------------- */
527 
528 static ssize_t revision_show(struct device *dev, struct device_attribute *attr, char *buf)
529 {
530 	struct usb_power_delivery *pd = to_usb_power_delivery(dev);
531 
532 	return sysfs_emit(buf, "%u.%u\n", (pd->revision >> 8) & 0xff, (pd->revision >> 4) & 0xf);
533 }
534 static DEVICE_ATTR_RO(revision);
535 
536 static ssize_t version_show(struct device *dev, struct device_attribute *attr, char *buf)
537 {
538 	struct usb_power_delivery *pd = to_usb_power_delivery(dev);
539 
540 	return sysfs_emit(buf, "%u.%u\n", (pd->version >> 8) & 0xff, (pd->version >> 4) & 0xf);
541 }
542 static DEVICE_ATTR_RO(version);
543 
544 static struct attribute *pd_attrs[] = {
545 	&dev_attr_revision.attr,
546 	&dev_attr_version.attr,
547 	NULL
548 };
549 
550 static umode_t pd_attr_is_visible(struct kobject *kobj, struct attribute *attr, int n)
551 {
552 	struct usb_power_delivery *pd = to_usb_power_delivery(kobj_to_dev(kobj));
553 
554 	if (attr == &dev_attr_version.attr && !pd->version)
555 		return 0;
556 
557 	return attr->mode;
558 }
559 
560 static const struct attribute_group pd_group = {
561 	.is_visible = pd_attr_is_visible,
562 	.attrs = pd_attrs,
563 };
564 __ATTRIBUTE_GROUPS(pd);
565 
566 static void pd_release(struct device *dev)
567 {
568 	struct usb_power_delivery *pd = to_usb_power_delivery(dev);
569 
570 	ida_simple_remove(&pd_ida, pd->id);
571 	kfree(pd);
572 }
573 
574 static struct device_type pd_type = {
575 	.name = "usb_power_delivery",
576 	.release = pd_release,
577 	.groups = pd_groups,
578 };
579 
580 struct usb_power_delivery *usb_power_delivery_find(const char *name)
581 {
582 	struct device *dev;
583 
584 	dev = class_find_device_by_name(&pd_class, name);
585 
586 	return dev ? to_usb_power_delivery(dev) : NULL;
587 }
588 
589 /**
590  * usb_power_delivery_register - Register USB Power Delivery Support.
591  * @parent: Parent device.
592  * @desc: Description of the USB PD contract.
593  *
594  * This routine can be used to register USB Power Delivery capabilities that a
595  * device or devices can support. These capabilities represent all the
596  * capabilities that can be negotiated with a partner, so not only the Power
597  * Capabilities that are negotiated using the USB PD Capabilities Message.
598  *
599  * The USB Power Delivery Support object that this routine generates can be used
600  * as the parent object for all the actual USB Power Delivery Messages and
601  * objects that can be negotiated with the partner.
602  *
603  * Returns handle to struct usb_power_delivery or ERR_PTR.
604  */
605 struct usb_power_delivery *
606 usb_power_delivery_register(struct device *parent, struct usb_power_delivery_desc *desc)
607 {
608 	struct usb_power_delivery *pd;
609 	int ret;
610 
611 	pd = kzalloc(sizeof(*pd), GFP_KERNEL);
612 	if (!pd)
613 		return ERR_PTR(-ENOMEM);
614 
615 	ret = ida_simple_get(&pd_ida, 0, 0, GFP_KERNEL);
616 	if (ret < 0) {
617 		kfree(pd);
618 		return ERR_PTR(ret);
619 	}
620 
621 	pd->id = ret;
622 	pd->revision = desc->revision;
623 	pd->version = desc->version;
624 
625 	pd->dev.parent = parent;
626 	pd->dev.type = &pd_type;
627 	pd->dev.class = &pd_class;
628 	dev_set_name(&pd->dev, "pd%d", pd->id);
629 
630 	ret = device_register(&pd->dev);
631 	if (ret) {
632 		put_device(&pd->dev);
633 		return ERR_PTR(ret);
634 	}
635 
636 	return pd;
637 }
638 EXPORT_SYMBOL_GPL(usb_power_delivery_register);
639 
640 /**
641  * usb_power_delivery_unregister - Unregister USB Power Delivery Support.
642  * @pd: The USB PD contract.
643  */
644 void usb_power_delivery_unregister(struct usb_power_delivery *pd)
645 {
646 	if (IS_ERR_OR_NULL(pd))
647 		return;
648 
649 	device_unregister(&pd->dev);
650 }
651 EXPORT_SYMBOL_GPL(usb_power_delivery_unregister);
652 
653 /**
654  * usb_power_delivery_link_device - Link device to its USB PD object.
655  * @pd: The USB PD instance.
656  * @dev: The device.
657  *
658  * This function can be used to create a symlink named "usb_power_delivery" for
659  * @dev that points to @pd.
660  */
661 int usb_power_delivery_link_device(struct usb_power_delivery *pd, struct device *dev)
662 {
663 	int ret;
664 
665 	if (IS_ERR_OR_NULL(pd) || !dev)
666 		return 0;
667 
668 	ret = sysfs_create_link(&dev->kobj, &pd->dev.kobj, "usb_power_delivery");
669 	if (ret)
670 		return ret;
671 
672 	get_device(&pd->dev);
673 	get_device(dev);
674 
675 	return 0;
676 }
677 EXPORT_SYMBOL_GPL(usb_power_delivery_link_device);
678 
679 /**
680  * usb_power_delivery_unlink_device - Unlink device from its USB PD object.
681  * @pd: The USB PD instance.
682  * @dev: The device.
683  *
684  * Remove the symlink that was previously created with pd_link_device().
685  */
686 void usb_power_delivery_unlink_device(struct usb_power_delivery *pd, struct device *dev)
687 {
688 	if (IS_ERR_OR_NULL(pd) || !dev)
689 		return;
690 
691 	sysfs_remove_link(&dev->kobj, "usb_power_delivery");
692 	put_device(&pd->dev);
693 	put_device(dev);
694 }
695 EXPORT_SYMBOL_GPL(usb_power_delivery_unlink_device);
696 
697 /* -------------------------------------------------------------------------- */
698 
699 int __init usb_power_delivery_init(void)
700 {
701 	return class_register(&pd_class);
702 }
703 
704 void __exit usb_power_delivery_exit(void)
705 {
706 	ida_destroy(&pd_ida);
707 	class_unregister(&pd_class);
708 }
709