xref: /linux/drivers/usb/misc/onboard_usb_dev.c (revision 8e1bb4a41aa78d6105e59186af3dcd545fc66e70)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Driver for onboard USB devices
4  *
5  * Copyright (c) 2022, Google LLC
6  */
7 
8 #include <linux/clk.h>
9 #include <linux/device.h>
10 #include <linux/export.h>
11 #include <linux/err.h>
12 #include <linux/gpio/consumer.h>
13 #include <linux/init.h>
14 #include <linux/kernel.h>
15 #include <linux/list.h>
16 #include <linux/module.h>
17 #include <linux/mutex.h>
18 #include <linux/of.h>
19 #include <linux/of_platform.h>
20 #include <linux/platform_device.h>
21 #include <linux/regulator/consumer.h>
22 #include <linux/slab.h>
23 #include <linux/suspend.h>
24 #include <linux/sysfs.h>
25 #include <linux/usb.h>
26 #include <linux/usb/hcd.h>
27 #include <linux/usb/onboard_dev.h>
28 #include <linux/workqueue.h>
29 
30 #include "onboard_usb_dev.h"
31 
32 static void onboard_dev_attach_usb_driver(struct work_struct *work);
33 
34 static struct usb_device_driver onboard_dev_usbdev_driver;
35 static DECLARE_WORK(attach_usb_driver_work, onboard_dev_attach_usb_driver);
36 
37 /************************** Platform driver **************************/
38 
39 struct usbdev_node {
40 	struct usb_device *udev;
41 	struct list_head list;
42 };
43 
44 struct onboard_dev {
45 	struct regulator_bulk_data supplies[MAX_SUPPLIES];
46 	struct device *dev;
47 	const struct onboard_dev_pdata *pdata;
48 	struct gpio_desc *reset_gpio;
49 	bool always_powered_in_suspend;
50 	bool is_powered_on;
51 	bool going_away;
52 	struct list_head udev_list;
53 	struct mutex lock;
54 	struct clk *clk;
55 };
56 
57 static int onboard_dev_get_regulators(struct onboard_dev *onboard_dev)
58 {
59 	const char * const *supply_names = onboard_dev->pdata->supply_names;
60 	unsigned int num_supplies = onboard_dev->pdata->num_supplies;
61 	struct device *dev = onboard_dev->dev;
62 	unsigned int i;
63 	int err;
64 
65 	if (num_supplies > MAX_SUPPLIES)
66 		return dev_err_probe(dev, -EINVAL, "max %d supplies supported!\n",
67 				     MAX_SUPPLIES);
68 
69 	for (i = 0; i < num_supplies; i++)
70 		onboard_dev->supplies[i].supply = supply_names[i];
71 
72 	err = devm_regulator_bulk_get(dev, num_supplies, onboard_dev->supplies);
73 	if (err)
74 		dev_err(dev, "Failed to get regulator supplies: %pe\n",
75 			ERR_PTR(err));
76 
77 	return err;
78 }
79 
80 static int onboard_dev_power_on(struct onboard_dev *onboard_dev)
81 {
82 	int err;
83 
84 	err = clk_prepare_enable(onboard_dev->clk);
85 	if (err) {
86 		dev_err(onboard_dev->dev, "failed to enable clock: %pe\n",
87 			ERR_PTR(err));
88 		return err;
89 	}
90 
91 	err = regulator_bulk_enable(onboard_dev->pdata->num_supplies,
92 				    onboard_dev->supplies);
93 	if (err) {
94 		dev_err(onboard_dev->dev, "failed to enable supplies: %pe\n",
95 			ERR_PTR(err));
96 		goto disable_clk;
97 	}
98 
99 	fsleep(onboard_dev->pdata->reset_us);
100 	gpiod_set_value_cansleep(onboard_dev->reset_gpio, 0);
101 
102 	onboard_dev->is_powered_on = true;
103 
104 	return 0;
105 
106 disable_clk:
107 	clk_disable_unprepare(onboard_dev->clk);
108 	return err;
109 }
110 
111 static int onboard_dev_power_off(struct onboard_dev *onboard_dev)
112 {
113 	int err;
114 
115 	gpiod_set_value_cansleep(onboard_dev->reset_gpio, 1);
116 
117 	err = regulator_bulk_disable(onboard_dev->pdata->num_supplies,
118 				     onboard_dev->supplies);
119 	if (err) {
120 		dev_err(onboard_dev->dev, "failed to disable supplies: %pe\n",
121 			ERR_PTR(err));
122 		return err;
123 	}
124 
125 	clk_disable_unprepare(onboard_dev->clk);
126 
127 	onboard_dev->is_powered_on = false;
128 
129 	return 0;
130 }
131 
132 static int __maybe_unused onboard_dev_suspend(struct device *dev)
133 {
134 	struct onboard_dev *onboard_dev = dev_get_drvdata(dev);
135 	struct usbdev_node *node;
136 	bool power_off = true;
137 
138 	if (onboard_dev->always_powered_in_suspend)
139 		return 0;
140 
141 	mutex_lock(&onboard_dev->lock);
142 
143 	list_for_each_entry(node, &onboard_dev->udev_list, list) {
144 		if (!device_may_wakeup(node->udev->bus->controller))
145 			continue;
146 
147 		if (usb_wakeup_enabled_descendants(node->udev)) {
148 			power_off = false;
149 			break;
150 		}
151 	}
152 
153 	mutex_unlock(&onboard_dev->lock);
154 
155 	if (!power_off)
156 		return 0;
157 
158 	return onboard_dev_power_off(onboard_dev);
159 }
160 
161 static int __maybe_unused onboard_dev_resume(struct device *dev)
162 {
163 	struct onboard_dev *onboard_dev = dev_get_drvdata(dev);
164 
165 	if (onboard_dev->is_powered_on)
166 		return 0;
167 
168 	return onboard_dev_power_on(onboard_dev);
169 }
170 
171 static inline void get_udev_link_name(const struct usb_device *udev, char *buf,
172 				      size_t size)
173 {
174 	snprintf(buf, size, "usb_dev.%s", dev_name(&udev->dev));
175 }
176 
177 static int onboard_dev_add_usbdev(struct onboard_dev *onboard_dev,
178 				  struct usb_device *udev)
179 {
180 	struct usbdev_node *node;
181 	char link_name[64];
182 	int err;
183 
184 	mutex_lock(&onboard_dev->lock);
185 
186 	if (onboard_dev->going_away) {
187 		err = -EINVAL;
188 		goto error;
189 	}
190 
191 	node = kzalloc(sizeof(*node), GFP_KERNEL);
192 	if (!node) {
193 		err = -ENOMEM;
194 		goto error;
195 	}
196 
197 	node->udev = udev;
198 
199 	list_add(&node->list, &onboard_dev->udev_list);
200 
201 	mutex_unlock(&onboard_dev->lock);
202 
203 	get_udev_link_name(udev, link_name, sizeof(link_name));
204 	WARN_ON(sysfs_create_link(&onboard_dev->dev->kobj, &udev->dev.kobj,
205 				  link_name));
206 
207 	return 0;
208 
209 error:
210 	mutex_unlock(&onboard_dev->lock);
211 
212 	return err;
213 }
214 
215 static void onboard_dev_remove_usbdev(struct onboard_dev *onboard_dev,
216 				      const struct usb_device *udev)
217 {
218 	struct usbdev_node *node;
219 	char link_name[64];
220 
221 	get_udev_link_name(udev, link_name, sizeof(link_name));
222 	sysfs_remove_link(&onboard_dev->dev->kobj, link_name);
223 
224 	mutex_lock(&onboard_dev->lock);
225 
226 	list_for_each_entry(node, &onboard_dev->udev_list, list) {
227 		if (node->udev == udev) {
228 			list_del(&node->list);
229 			kfree(node);
230 			break;
231 		}
232 	}
233 
234 	mutex_unlock(&onboard_dev->lock);
235 }
236 
237 static ssize_t always_powered_in_suspend_show(struct device *dev,
238 					      struct device_attribute *attr,
239 					      char *buf)
240 {
241 	const struct onboard_dev *onboard_dev = dev_get_drvdata(dev);
242 
243 	return sysfs_emit(buf, "%d\n", onboard_dev->always_powered_in_suspend);
244 }
245 
246 static ssize_t always_powered_in_suspend_store(struct device *dev,
247 					       struct device_attribute *attr,
248 					       const char *buf, size_t count)
249 {
250 	struct onboard_dev *onboard_dev = dev_get_drvdata(dev);
251 	bool val;
252 	int ret;
253 
254 	ret = kstrtobool(buf, &val);
255 	if (ret < 0)
256 		return ret;
257 
258 	onboard_dev->always_powered_in_suspend = val;
259 
260 	return count;
261 }
262 static DEVICE_ATTR_RW(always_powered_in_suspend);
263 
264 static struct attribute *onboard_dev_attrs[] = {
265 	&dev_attr_always_powered_in_suspend.attr,
266 	NULL,
267 };
268 
269 static umode_t onboard_dev_attrs_are_visible(struct kobject *kobj,
270 					     struct attribute *attr,
271 					     int n)
272 {
273 	struct device *dev = kobj_to_dev(kobj);
274 	struct onboard_dev *onboard_dev = dev_get_drvdata(dev);
275 
276 	if (attr == &dev_attr_always_powered_in_suspend.attr &&
277 	    !onboard_dev->pdata->is_hub)
278 		return 0;
279 
280 	return attr->mode;
281 }
282 
283 static const struct attribute_group onboard_dev_group = {
284 	.is_visible = onboard_dev_attrs_are_visible,
285 	.attrs = onboard_dev_attrs,
286 };
287 __ATTRIBUTE_GROUPS(onboard_dev);
288 
289 
290 static void onboard_dev_attach_usb_driver(struct work_struct *work)
291 {
292 	int err;
293 
294 	err = driver_attach(&onboard_dev_usbdev_driver.driver);
295 	if (err)
296 		pr_err("Failed to attach USB driver: %pe\n", ERR_PTR(err));
297 }
298 
299 static int onboard_dev_probe(struct platform_device *pdev)
300 {
301 	struct device *dev = &pdev->dev;
302 	struct onboard_dev *onboard_dev;
303 	int err;
304 
305 	onboard_dev = devm_kzalloc(dev, sizeof(*onboard_dev), GFP_KERNEL);
306 	if (!onboard_dev)
307 		return -ENOMEM;
308 
309 	onboard_dev->pdata = device_get_match_data(dev);
310 	if (!onboard_dev->pdata)
311 		return -EINVAL;
312 
313 	if (!onboard_dev->pdata->is_hub)
314 		onboard_dev->always_powered_in_suspend = true;
315 
316 	onboard_dev->dev = dev;
317 
318 	err = onboard_dev_get_regulators(onboard_dev);
319 	if (err)
320 		return err;
321 
322 	onboard_dev->clk = devm_clk_get_optional(dev, NULL);
323 	if (IS_ERR(onboard_dev->clk))
324 		return dev_err_probe(dev, PTR_ERR(onboard_dev->clk),
325 				     "failed to get clock\n");
326 
327 	onboard_dev->reset_gpio = devm_gpiod_get_optional(dev, "reset",
328 							  GPIOD_OUT_HIGH);
329 	if (IS_ERR(onboard_dev->reset_gpio))
330 		return dev_err_probe(dev, PTR_ERR(onboard_dev->reset_gpio),
331 				     "failed to get reset GPIO\n");
332 
333 	mutex_init(&onboard_dev->lock);
334 	INIT_LIST_HEAD(&onboard_dev->udev_list);
335 
336 	dev_set_drvdata(dev, onboard_dev);
337 
338 	err = onboard_dev_power_on(onboard_dev);
339 	if (err)
340 		return err;
341 
342 	/*
343 	 * The USB driver might have been detached from the USB devices by
344 	 * onboard_dev_remove() (e.g. through an 'unbind' by userspace),
345 	 * make sure to re-attach it if needed.
346 	 *
347 	 * This needs to be done deferred to avoid self-deadlocks on systems
348 	 * with nested onboard hubs.
349 	 */
350 	schedule_work(&attach_usb_driver_work);
351 
352 	return 0;
353 }
354 
355 static void onboard_dev_remove(struct platform_device *pdev)
356 {
357 	struct onboard_dev *onboard_dev = dev_get_drvdata(&pdev->dev);
358 	struct usbdev_node *node;
359 	struct usb_device *udev;
360 
361 	onboard_dev->going_away = true;
362 
363 	mutex_lock(&onboard_dev->lock);
364 
365 	/* unbind the USB devices to avoid dangling references to this device */
366 	while (!list_empty(&onboard_dev->udev_list)) {
367 		node = list_first_entry(&onboard_dev->udev_list,
368 					struct usbdev_node, list);
369 		udev = node->udev;
370 
371 		/*
372 		 * Unbinding the driver will call onboard_dev_remove_usbdev(),
373 		 * which acquires onboard_dev->lock. We must release the lock
374 		 * first.
375 		 */
376 		get_device(&udev->dev);
377 		mutex_unlock(&onboard_dev->lock);
378 		device_release_driver(&udev->dev);
379 		put_device(&udev->dev);
380 		mutex_lock(&onboard_dev->lock);
381 	}
382 
383 	mutex_unlock(&onboard_dev->lock);
384 
385 	onboard_dev_power_off(onboard_dev);
386 }
387 
388 MODULE_DEVICE_TABLE(of, onboard_dev_match);
389 
390 static const struct dev_pm_ops __maybe_unused onboard_dev_pm_ops = {
391 	SET_LATE_SYSTEM_SLEEP_PM_OPS(onboard_dev_suspend, onboard_dev_resume)
392 };
393 
394 static struct platform_driver onboard_dev_driver = {
395 	.probe = onboard_dev_probe,
396 	.remove_new = onboard_dev_remove,
397 
398 	.driver = {
399 		.name = "onboard-usb-dev",
400 		.of_match_table = onboard_dev_match,
401 		.pm = pm_ptr(&onboard_dev_pm_ops),
402 		.dev_groups = onboard_dev_groups,
403 	},
404 };
405 
406 /************************** USB driver **************************/
407 
408 #define VENDOR_ID_CYPRESS	0x04b4
409 #define VENDOR_ID_GENESYS	0x05e3
410 #define VENDOR_ID_MICROCHIP	0x0424
411 #define VENDOR_ID_REALTEK	0x0bda
412 #define VENDOR_ID_TI		0x0451
413 #define VENDOR_ID_VIA		0x2109
414 #define VENDOR_ID_XMOS		0x20B1
415 
416 /*
417  * Returns the onboard_dev platform device that is associated with the USB
418  * device passed as parameter.
419  */
420 static struct onboard_dev *_find_onboard_dev(struct device *dev)
421 {
422 	struct platform_device *pdev;
423 	struct device_node *np;
424 	struct onboard_dev *onboard_dev;
425 
426 	pdev = of_find_device_by_node(dev->of_node);
427 	if (!pdev) {
428 		np = of_parse_phandle(dev->of_node, "peer-hub", 0);
429 		if (!np) {
430 			dev_err(dev, "failed to find device node for peer hub\n");
431 			return ERR_PTR(-EINVAL);
432 		}
433 
434 		pdev = of_find_device_by_node(np);
435 		of_node_put(np);
436 
437 		if (!pdev)
438 			return ERR_PTR(-ENODEV);
439 	}
440 
441 	onboard_dev = dev_get_drvdata(&pdev->dev);
442 	put_device(&pdev->dev);
443 
444 	/*
445 	 * The presence of drvdata indicates that the platform driver finished
446 	 * probing. This handles the case where (conceivably) we could be
447 	 * running at the exact same time as the platform driver's probe. If
448 	 * we detect the race we request probe deferral and we'll come back and
449 	 * try again.
450 	 */
451 	if (!onboard_dev)
452 		return ERR_PTR(-EPROBE_DEFER);
453 
454 	return onboard_dev;
455 }
456 
457 static bool onboard_dev_usbdev_match(struct usb_device *udev)
458 {
459 	/* Onboard devices using this driver must have a device tree node */
460 	return !!udev->dev.of_node;
461 }
462 
463 static int onboard_dev_usbdev_probe(struct usb_device *udev)
464 {
465 	struct device *dev = &udev->dev;
466 	struct onboard_dev *onboard_dev;
467 	int err;
468 
469 	onboard_dev = _find_onboard_dev(dev);
470 	if (IS_ERR(onboard_dev))
471 		return PTR_ERR(onboard_dev);
472 
473 	dev_set_drvdata(dev, onboard_dev);
474 
475 	err = onboard_dev_add_usbdev(onboard_dev, udev);
476 	if (err)
477 		return err;
478 
479 	return 0;
480 }
481 
482 static void onboard_dev_usbdev_disconnect(struct usb_device *udev)
483 {
484 	struct onboard_dev *onboard_dev = dev_get_drvdata(&udev->dev);
485 
486 	onboard_dev_remove_usbdev(onboard_dev, udev);
487 }
488 
489 static const struct usb_device_id onboard_dev_id_table[] = {
490 	{ USB_DEVICE(VENDOR_ID_CYPRESS, 0x6504) }, /* CYUSB33{0,1,2}x/CYUSB230x 3.0 HUB */
491 	{ USB_DEVICE(VENDOR_ID_CYPRESS, 0x6506) }, /* CYUSB33{0,1,2}x/CYUSB230x 2.0 HUB */
492 	{ USB_DEVICE(VENDOR_ID_CYPRESS, 0x6570) }, /* CY7C6563x 2.0 HUB */
493 	{ USB_DEVICE(VENDOR_ID_GENESYS, 0x0608) }, /* Genesys Logic GL850G USB 2.0 HUB */
494 	{ USB_DEVICE(VENDOR_ID_GENESYS, 0x0610) }, /* Genesys Logic GL852G USB 2.0 HUB */
495 	{ USB_DEVICE(VENDOR_ID_GENESYS, 0x0620) }, /* Genesys Logic GL3523 USB 3.1 HUB */
496 	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2412) }, /* USB2412 USB 2.0 HUB */
497 	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2514) }, /* USB2514B USB 2.0 HUB */
498 	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2517) }, /* USB2517 USB 2.0 HUB */
499 	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2744) }, /* USB5744 USB 2.0 HUB */
500 	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x5744) }, /* USB5744 USB 3.0 HUB */
501 	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x0411) }, /* RTS5411 USB 3.1 HUB */
502 	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x5411) }, /* RTS5411 USB 2.1 HUB */
503 	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x0414) }, /* RTS5414 USB 3.2 HUB */
504 	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x5414) }, /* RTS5414 USB 2.1 HUB */
505 	{ USB_DEVICE(VENDOR_ID_TI, 0x8025) }, /* TI USB8020B 3.0 HUB */
506 	{ USB_DEVICE(VENDOR_ID_TI, 0x8027) }, /* TI USB8020B 2.0 HUB */
507 	{ USB_DEVICE(VENDOR_ID_TI, 0x8140) }, /* TI USB8041 3.0 HUB */
508 	{ USB_DEVICE(VENDOR_ID_TI, 0x8142) }, /* TI USB8041 2.0 HUB */
509 	{ USB_DEVICE(VENDOR_ID_VIA, 0x0817) }, /* VIA VL817 3.1 HUB */
510 	{ USB_DEVICE(VENDOR_ID_VIA, 0x2817) }, /* VIA VL817 2.0 HUB */
511 	{ USB_DEVICE(VENDOR_ID_XMOS, 0x0013) }, /* XMOS XVF3500 Voice Processor */
512 	{}
513 };
514 MODULE_DEVICE_TABLE(usb, onboard_dev_id_table);
515 
516 static struct usb_device_driver onboard_dev_usbdev_driver = {
517 	.name = "onboard-usb-dev",
518 	.match = onboard_dev_usbdev_match,
519 	.probe = onboard_dev_usbdev_probe,
520 	.disconnect = onboard_dev_usbdev_disconnect,
521 	.generic_subclass = 1,
522 	.supports_autosuspend =	1,
523 	.id_table = onboard_dev_id_table,
524 };
525 
526 static int __init onboard_dev_init(void)
527 {
528 	int ret;
529 
530 	ret = usb_register_device_driver(&onboard_dev_usbdev_driver, THIS_MODULE);
531 	if (ret)
532 		return ret;
533 
534 	ret = platform_driver_register(&onboard_dev_driver);
535 	if (ret)
536 		usb_deregister_device_driver(&onboard_dev_usbdev_driver);
537 
538 	return ret;
539 }
540 module_init(onboard_dev_init);
541 
542 static void __exit onboard_dev_exit(void)
543 {
544 	usb_deregister_device_driver(&onboard_dev_usbdev_driver);
545 	platform_driver_unregister(&onboard_dev_driver);
546 
547 	cancel_work_sync(&attach_usb_driver_work);
548 }
549 module_exit(onboard_dev_exit);
550 
551 MODULE_AUTHOR("Matthias Kaehlcke <mka@chromium.org>");
552 MODULE_DESCRIPTION("Driver for discrete onboard USB devices");
553 MODULE_LICENSE("GPL v2");
554