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 */
34static const char * const supply_names[] = {
35	"vdd",
36	"vdd2",
37};
38
39#define MAX_SUPPLIES ARRAY_SIZE(supply_names)
40
41static void onboard_hub_attach_usb_driver(struct work_struct *work);
42
43static struct usb_device_driver onboard_hub_usbdev_driver;
44static DECLARE_WORK(attach_usb_driver_work, onboard_hub_attach_usb_driver);
45
46/************************** Platform driver **************************/
47
48struct usbdev_node {
49	struct usb_device *udev;
50	struct list_head list;
51};
52
53struct 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
65static 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
83static 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
100static 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
129static 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
139static 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
144static 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
174error:
175	mutex_unlock(&hub->lock);
176
177	return err;
178}
179
180static 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
201static 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
209static 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}
224static DEVICE_ATTR_RW(always_powered_in_suspend);
225
226static struct attribute *onboard_hub_attrs[] = {
227	&dev_attr_always_powered_in_suspend.attr,
228	NULL,
229};
230ATTRIBUTE_GROUPS(onboard_hub);
231
232static 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
241static 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
302static 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
333MODULE_DEVICE_TABLE(of, onboard_hub_match);
334
335static 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
339static 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 */
364static 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
401static 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
424static 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
431static 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};
452MODULE_DEVICE_TABLE(usb, onboard_hub_id_table);
453
454static 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
463static 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}
477module_init(onboard_hub_init);
478
479static 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}
486module_exit(onboard_hub_exit);
487
488MODULE_AUTHOR("Matthias Kaehlcke <mka@chromium.org>");
489MODULE_DESCRIPTION("Driver for discrete onboard USB hubs");
490MODULE_LICENSE("GPL v2");
491