1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Driver for onboard USB hubs
4  *
5  * Copyright (c) 2022, Google LLC
6  */
7 
8 #include <linux/device.h>
9 #include <linux/export.h>
10 #include <linux/gpio/consumer.h>
11 #include <linux/init.h>
12 #include <linux/kernel.h>
13 #include <linux/list.h>
14 #include <linux/module.h>
15 #include <linux/mutex.h>
16 #include <linux/of.h>
17 #include <linux/of_platform.h>
18 #include <linux/platform_device.h>
19 #include <linux/regulator/consumer.h>
20 #include <linux/slab.h>
21 #include <linux/suspend.h>
22 #include <linux/sysfs.h>
23 #include <linux/usb.h>
24 #include <linux/usb/hcd.h>
25 #include <linux/usb/onboard_hub.h>
26 #include <linux/workqueue.h>
27 
28 #include "onboard_usb_hub.h"
29 
30 /*
31  * Use generic names, as the actual names might differ between hubs. If a new
32  * hub requires more than the currently supported supplies, add a new one here.
33  */
34 static const char * const supply_names[] = {
35 	"vdd",
36 	"vdd2",
37 };
38 
39 #define MAX_SUPPLIES ARRAY_SIZE(supply_names)
40 
41 static void onboard_hub_attach_usb_driver(struct work_struct *work);
42 
43 static struct usb_device_driver onboard_hub_usbdev_driver;
44 static DECLARE_WORK(attach_usb_driver_work, onboard_hub_attach_usb_driver);
45 
46 /************************** Platform driver **************************/
47 
48 struct usbdev_node {
49 	struct usb_device *udev;
50 	struct list_head list;
51 };
52 
53 struct onboard_hub {
54 	struct regulator_bulk_data supplies[MAX_SUPPLIES];
55 	struct device *dev;
56 	const struct onboard_hub_pdata *pdata;
57 	struct gpio_desc *reset_gpio;
58 	bool always_powered_in_suspend;
59 	bool is_powered_on;
60 	bool going_away;
61 	struct list_head udev_list;
62 	struct mutex lock;
63 };
64 
onboard_hub_power_on(struct onboard_hub * hub)65 static int onboard_hub_power_on(struct onboard_hub *hub)
66 {
67 	int err;
68 
69 	err = regulator_bulk_enable(hub->pdata->num_supplies, hub->supplies);
70 	if (err) {
71 		dev_err(hub->dev, "failed to enable supplies: %d\n", err);
72 		return err;
73 	}
74 
75 	fsleep(hub->pdata->reset_us);
76 	gpiod_set_value_cansleep(hub->reset_gpio, 0);
77 
78 	hub->is_powered_on = true;
79 
80 	return 0;
81 }
82 
onboard_hub_power_off(struct onboard_hub * hub)83 static int onboard_hub_power_off(struct onboard_hub *hub)
84 {
85 	int err;
86 
87 	gpiod_set_value_cansleep(hub->reset_gpio, 1);
88 
89 	err = regulator_bulk_disable(hub->pdata->num_supplies, hub->supplies);
90 	if (err) {
91 		dev_err(hub->dev, "failed to disable supplies: %d\n", err);
92 		return err;
93 	}
94 
95 	hub->is_powered_on = false;
96 
97 	return 0;
98 }
99 
onboard_hub_suspend(struct device * dev)100 static int __maybe_unused onboard_hub_suspend(struct device *dev)
101 {
102 	struct onboard_hub *hub = dev_get_drvdata(dev);
103 	struct usbdev_node *node;
104 	bool power_off = true;
105 
106 	if (hub->always_powered_in_suspend)
107 		return 0;
108 
109 	mutex_lock(&hub->lock);
110 
111 	list_for_each_entry(node, &hub->udev_list, list) {
112 		if (!device_may_wakeup(node->udev->bus->controller))
113 			continue;
114 
115 		if (usb_wakeup_enabled_descendants(node->udev)) {
116 			power_off = false;
117 			break;
118 		}
119 	}
120 
121 	mutex_unlock(&hub->lock);
122 
123 	if (!power_off)
124 		return 0;
125 
126 	return onboard_hub_power_off(hub);
127 }
128 
onboard_hub_resume(struct device * dev)129 static int __maybe_unused onboard_hub_resume(struct device *dev)
130 {
131 	struct onboard_hub *hub = dev_get_drvdata(dev);
132 
133 	if (hub->is_powered_on)
134 		return 0;
135 
136 	return onboard_hub_power_on(hub);
137 }
138 
get_udev_link_name(const struct usb_device * udev,char * buf,size_t size)139 static inline void get_udev_link_name(const struct usb_device *udev, char *buf, size_t size)
140 {
141 	snprintf(buf, size, "usb_dev.%s", dev_name(&udev->dev));
142 }
143 
onboard_hub_add_usbdev(struct onboard_hub * hub,struct usb_device * udev)144 static int onboard_hub_add_usbdev(struct onboard_hub *hub, struct usb_device *udev)
145 {
146 	struct usbdev_node *node;
147 	char link_name[64];
148 	int err;
149 
150 	mutex_lock(&hub->lock);
151 
152 	if (hub->going_away) {
153 		err = -EINVAL;
154 		goto error;
155 	}
156 
157 	node = kzalloc(sizeof(*node), GFP_KERNEL);
158 	if (!node) {
159 		err = -ENOMEM;
160 		goto error;
161 	}
162 
163 	node->udev = udev;
164 
165 	list_add(&node->list, &hub->udev_list);
166 
167 	mutex_unlock(&hub->lock);
168 
169 	get_udev_link_name(udev, link_name, sizeof(link_name));
170 	WARN_ON(sysfs_create_link(&hub->dev->kobj, &udev->dev.kobj, link_name));
171 
172 	return 0;
173 
174 error:
175 	mutex_unlock(&hub->lock);
176 
177 	return err;
178 }
179 
onboard_hub_remove_usbdev(struct onboard_hub * hub,const struct usb_device * udev)180 static void onboard_hub_remove_usbdev(struct onboard_hub *hub, const struct usb_device *udev)
181 {
182 	struct usbdev_node *node;
183 	char link_name[64];
184 
185 	get_udev_link_name(udev, link_name, sizeof(link_name));
186 	sysfs_remove_link(&hub->dev->kobj, link_name);
187 
188 	mutex_lock(&hub->lock);
189 
190 	list_for_each_entry(node, &hub->udev_list, list) {
191 		if (node->udev == udev) {
192 			list_del(&node->list);
193 			kfree(node);
194 			break;
195 		}
196 	}
197 
198 	mutex_unlock(&hub->lock);
199 }
200 
always_powered_in_suspend_show(struct device * dev,struct device_attribute * attr,char * buf)201 static ssize_t always_powered_in_suspend_show(struct device *dev, struct device_attribute *attr,
202 			   char *buf)
203 {
204 	const struct onboard_hub *hub = dev_get_drvdata(dev);
205 
206 	return sysfs_emit(buf, "%d\n", hub->always_powered_in_suspend);
207 }
208 
always_powered_in_suspend_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)209 static ssize_t always_powered_in_suspend_store(struct device *dev, struct device_attribute *attr,
210 			    const char *buf, size_t count)
211 {
212 	struct onboard_hub *hub = dev_get_drvdata(dev);
213 	bool val;
214 	int ret;
215 
216 	ret = kstrtobool(buf, &val);
217 	if (ret < 0)
218 		return ret;
219 
220 	hub->always_powered_in_suspend = val;
221 
222 	return count;
223 }
224 static DEVICE_ATTR_RW(always_powered_in_suspend);
225 
226 static struct attribute *onboard_hub_attrs[] = {
227 	&dev_attr_always_powered_in_suspend.attr,
228 	NULL,
229 };
230 ATTRIBUTE_GROUPS(onboard_hub);
231 
onboard_hub_attach_usb_driver(struct work_struct * work)232 static void onboard_hub_attach_usb_driver(struct work_struct *work)
233 {
234 	int err;
235 
236 	err = driver_attach(&onboard_hub_usbdev_driver.drvwrap.driver);
237 	if (err)
238 		pr_err("Failed to attach USB driver: %d\n", err);
239 }
240 
onboard_hub_probe(struct platform_device * pdev)241 static int onboard_hub_probe(struct platform_device *pdev)
242 {
243 	const struct of_device_id *of_id;
244 	struct device *dev = &pdev->dev;
245 	struct onboard_hub *hub;
246 	unsigned int i;
247 	int err;
248 
249 	hub = devm_kzalloc(dev, sizeof(*hub), GFP_KERNEL);
250 	if (!hub)
251 		return -ENOMEM;
252 
253 	of_id = of_match_device(onboard_hub_match, &pdev->dev);
254 	if (!of_id)
255 		return -ENODEV;
256 
257 	hub->pdata = of_id->data;
258 	if (!hub->pdata)
259 		return -EINVAL;
260 
261 	if (hub->pdata->num_supplies > MAX_SUPPLIES)
262 		return dev_err_probe(dev, -EINVAL, "max %zu supplies supported!\n",
263 				     MAX_SUPPLIES);
264 
265 	for (i = 0; i < hub->pdata->num_supplies; i++)
266 		hub->supplies[i].supply = supply_names[i];
267 
268 	err = devm_regulator_bulk_get(dev, hub->pdata->num_supplies, hub->supplies);
269 	if (err) {
270 		dev_err(dev, "Failed to get regulator supplies: %d\n", err);
271 		return err;
272 	}
273 
274 	hub->reset_gpio = devm_gpiod_get_optional(dev, "reset",
275 						  GPIOD_OUT_HIGH);
276 	if (IS_ERR(hub->reset_gpio))
277 		return dev_err_probe(dev, PTR_ERR(hub->reset_gpio), "failed to get reset GPIO\n");
278 
279 	hub->dev = dev;
280 	mutex_init(&hub->lock);
281 	INIT_LIST_HEAD(&hub->udev_list);
282 
283 	dev_set_drvdata(dev, hub);
284 
285 	err = onboard_hub_power_on(hub);
286 	if (err)
287 		return err;
288 
289 	/*
290 	 * The USB driver might have been detached from the USB devices by
291 	 * onboard_hub_remove() (e.g. through an 'unbind' by userspace),
292 	 * make sure to re-attach it if needed.
293 	 *
294 	 * This needs to be done deferred to avoid self-deadlocks on systems
295 	 * with nested onboard hubs.
296 	 */
297 	schedule_work(&attach_usb_driver_work);
298 
299 	return 0;
300 }
301 
onboard_hub_remove(struct platform_device * pdev)302 static void onboard_hub_remove(struct platform_device *pdev)
303 {
304 	struct onboard_hub *hub = dev_get_drvdata(&pdev->dev);
305 	struct usbdev_node *node;
306 	struct usb_device *udev;
307 
308 	hub->going_away = true;
309 
310 	mutex_lock(&hub->lock);
311 
312 	/* unbind the USB devices to avoid dangling references to this device */
313 	while (!list_empty(&hub->udev_list)) {
314 		node = list_first_entry(&hub->udev_list, struct usbdev_node, list);
315 		udev = node->udev;
316 
317 		/*
318 		 * Unbinding the driver will call onboard_hub_remove_usbdev(),
319 		 * which acquires hub->lock.  We must release the lock first.
320 		 */
321 		get_device(&udev->dev);
322 		mutex_unlock(&hub->lock);
323 		device_release_driver(&udev->dev);
324 		put_device(&udev->dev);
325 		mutex_lock(&hub->lock);
326 	}
327 
328 	mutex_unlock(&hub->lock);
329 
330 	onboard_hub_power_off(hub);
331 }
332 
333 MODULE_DEVICE_TABLE(of, onboard_hub_match);
334 
335 static const struct dev_pm_ops __maybe_unused onboard_hub_pm_ops = {
336 	SET_LATE_SYSTEM_SLEEP_PM_OPS(onboard_hub_suspend, onboard_hub_resume)
337 };
338 
339 static struct platform_driver onboard_hub_driver = {
340 	.probe = onboard_hub_probe,
341 	.remove_new = onboard_hub_remove,
342 
343 	.driver = {
344 		.name = "onboard-usb-hub",
345 		.of_match_table = onboard_hub_match,
346 		.pm = pm_ptr(&onboard_hub_pm_ops),
347 		.dev_groups = onboard_hub_groups,
348 	},
349 };
350 
351 /************************** USB driver **************************/
352 
353 #define VENDOR_ID_CYPRESS	0x04b4
354 #define VENDOR_ID_GENESYS	0x05e3
355 #define VENDOR_ID_MICROCHIP	0x0424
356 #define VENDOR_ID_REALTEK	0x0bda
357 #define VENDOR_ID_TI		0x0451
358 #define VENDOR_ID_VIA		0x2109
359 
360 /*
361  * Returns the onboard_hub platform device that is associated with the USB
362  * device passed as parameter.
363  */
_find_onboard_hub(struct device * dev)364 static struct onboard_hub *_find_onboard_hub(struct device *dev)
365 {
366 	struct platform_device *pdev;
367 	struct device_node *np;
368 	struct onboard_hub *hub;
369 
370 	pdev = of_find_device_by_node(dev->of_node);
371 	if (!pdev) {
372 		np = of_parse_phandle(dev->of_node, "peer-hub", 0);
373 		if (!np) {
374 			dev_err(dev, "failed to find device node for peer hub\n");
375 			return ERR_PTR(-EINVAL);
376 		}
377 
378 		pdev = of_find_device_by_node(np);
379 		of_node_put(np);
380 
381 		if (!pdev)
382 			return ERR_PTR(-ENODEV);
383 	}
384 
385 	hub = dev_get_drvdata(&pdev->dev);
386 	put_device(&pdev->dev);
387 
388 	/*
389 	 * The presence of drvdata ('hub') indicates that the platform driver
390 	 * finished probing. This handles the case where (conceivably) we could
391 	 * be running at the exact same time as the platform driver's probe. If
392 	 * we detect the race we request probe deferral and we'll come back and
393 	 * try again.
394 	 */
395 	if (!hub)
396 		return ERR_PTR(-EPROBE_DEFER);
397 
398 	return hub;
399 }
400 
onboard_hub_usbdev_probe(struct usb_device * udev)401 static int onboard_hub_usbdev_probe(struct usb_device *udev)
402 {
403 	struct device *dev = &udev->dev;
404 	struct onboard_hub *hub;
405 	int err;
406 
407 	/* ignore supported hubs without device tree node */
408 	if (!dev->of_node)
409 		return -ENODEV;
410 
411 	hub = _find_onboard_hub(dev);
412 	if (IS_ERR(hub))
413 		return PTR_ERR(hub);
414 
415 	dev_set_drvdata(dev, hub);
416 
417 	err = onboard_hub_add_usbdev(hub, udev);
418 	if (err)
419 		return err;
420 
421 	return 0;
422 }
423 
onboard_hub_usbdev_disconnect(struct usb_device * udev)424 static void onboard_hub_usbdev_disconnect(struct usb_device *udev)
425 {
426 	struct onboard_hub *hub = dev_get_drvdata(&udev->dev);
427 
428 	onboard_hub_remove_usbdev(hub, udev);
429 }
430 
431 static const struct usb_device_id onboard_hub_id_table[] = {
432 	{ USB_DEVICE(VENDOR_ID_CYPRESS, 0x6504) }, /* CYUSB33{0,1,2}x/CYUSB230x 3.0 */
433 	{ USB_DEVICE(VENDOR_ID_CYPRESS, 0x6506) }, /* CYUSB33{0,1,2}x/CYUSB230x 2.0 */
434 	{ USB_DEVICE(VENDOR_ID_GENESYS, 0x0608) }, /* Genesys Logic GL850G USB 2.0 */
435 	{ USB_DEVICE(VENDOR_ID_GENESYS, 0x0610) }, /* Genesys Logic GL852G USB 2.0 */
436 	{ USB_DEVICE(VENDOR_ID_GENESYS, 0x0620) }, /* Genesys Logic GL3523 USB 3.1 */
437 	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2412) }, /* USB2412 USB 2.0 */
438 	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2514) }, /* USB2514B USB 2.0 */
439 	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2517) }, /* USB2517 USB 2.0 */
440 	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2744) }, /* USB5744 USB 2.0 */
441 	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x5744) }, /* USB5744 USB 3.0 */
442 	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x0411) }, /* RTS5411 USB 3.1 */
443 	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x5411) }, /* RTS5411 USB 2.1 */
444 	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x0414) }, /* RTS5414 USB 3.2 */
445 	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x5414) }, /* RTS5414 USB 2.1 */
446 	{ USB_DEVICE(VENDOR_ID_TI, 0x8140) }, /* TI USB8041 3.0 */
447 	{ USB_DEVICE(VENDOR_ID_TI, 0x8142) }, /* TI USB8041 2.0 */
448 	{ USB_DEVICE(VENDOR_ID_VIA, 0x0817) }, /* VIA VL817 3.1 */
449 	{ USB_DEVICE(VENDOR_ID_VIA, 0x2817) }, /* VIA VL817 2.0 */
450 	{}
451 };
452 MODULE_DEVICE_TABLE(usb, onboard_hub_id_table);
453 
454 static struct usb_device_driver onboard_hub_usbdev_driver = {
455 	.name = "onboard-usb-hub",
456 	.probe = onboard_hub_usbdev_probe,
457 	.disconnect = onboard_hub_usbdev_disconnect,
458 	.generic_subclass = 1,
459 	.supports_autosuspend =	1,
460 	.id_table = onboard_hub_id_table,
461 };
462 
onboard_hub_init(void)463 static int __init onboard_hub_init(void)
464 {
465 	int ret;
466 
467 	ret = usb_register_device_driver(&onboard_hub_usbdev_driver, THIS_MODULE);
468 	if (ret)
469 		return ret;
470 
471 	ret = platform_driver_register(&onboard_hub_driver);
472 	if (ret)
473 		usb_deregister_device_driver(&onboard_hub_usbdev_driver);
474 
475 	return ret;
476 }
477 module_init(onboard_hub_init);
478 
onboard_hub_exit(void)479 static void __exit onboard_hub_exit(void)
480 {
481 	usb_deregister_device_driver(&onboard_hub_usbdev_driver);
482 	platform_driver_unregister(&onboard_hub_driver);
483 
484 	cancel_work_sync(&attach_usb_driver_work);
485 }
486 module_exit(onboard_hub_exit);
487 
488 MODULE_AUTHOR("Matthias Kaehlcke <mka@chromium.org>");
489 MODULE_DESCRIPTION("Driver for discrete onboard USB hubs");
490 MODULE_LICENSE("GPL v2");
491