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/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_hub.h>
28#include <linux/workqueue.h>
29
30#include "onboard_usb_hub.h"
31
32/*
33 * Use generic names, as the actual names might differ between hubs. If a new
34 * hub requires more than the currently supported supplies, add a new one here.
35 */
36static const char * const supply_names[] = {
37	"vdd",
38	"vdd2",
39};
40
41#define MAX_SUPPLIES ARRAY_SIZE(supply_names)
42
43static void onboard_hub_attach_usb_driver(struct work_struct *work);
44
45static struct usb_device_driver onboard_hub_usbdev_driver;
46static DECLARE_WORK(attach_usb_driver_work, onboard_hub_attach_usb_driver);
47
48/************************** Platform driver **************************/
49
50struct usbdev_node {
51	struct usb_device *udev;
52	struct list_head list;
53};
54
55struct onboard_hub {
56	struct regulator_bulk_data supplies[MAX_SUPPLIES];
57	struct device *dev;
58	const struct onboard_hub_pdata *pdata;
59	struct gpio_desc *reset_gpio;
60	bool always_powered_in_suspend;
61	bool is_powered_on;
62	bool going_away;
63	struct list_head udev_list;
64	struct mutex lock;
65	struct clk *clk;
66};
67
68static int onboard_hub_power_on(struct onboard_hub *hub)
69{
70	int err;
71
72	err = clk_prepare_enable(hub->clk);
73	if (err) {
74		dev_err(hub->dev, "failed to enable clock: %pe\n", ERR_PTR(err));
75		return err;
76	}
77
78	err = regulator_bulk_enable(hub->pdata->num_supplies, hub->supplies);
79	if (err) {
80		dev_err(hub->dev, "failed to enable supplies: %pe\n", ERR_PTR(err));
81		goto disable_clk;
82	}
83
84	fsleep(hub->pdata->reset_us);
85	gpiod_set_value_cansleep(hub->reset_gpio, 0);
86
87	hub->is_powered_on = true;
88
89	return 0;
90
91disable_clk:
92	clk_disable_unprepare(hub->clk);
93	return err;
94}
95
96static int onboard_hub_power_off(struct onboard_hub *hub)
97{
98	int err;
99
100	gpiod_set_value_cansleep(hub->reset_gpio, 1);
101
102	err = regulator_bulk_disable(hub->pdata->num_supplies, hub->supplies);
103	if (err) {
104		dev_err(hub->dev, "failed to disable supplies: %pe\n", ERR_PTR(err));
105		return err;
106	}
107
108	clk_disable_unprepare(hub->clk);
109
110	hub->is_powered_on = false;
111
112	return 0;
113}
114
115static int __maybe_unused onboard_hub_suspend(struct device *dev)
116{
117	struct onboard_hub *hub = dev_get_drvdata(dev);
118	struct usbdev_node *node;
119	bool power_off = true;
120
121	if (hub->always_powered_in_suspend)
122		return 0;
123
124	mutex_lock(&hub->lock);
125
126	list_for_each_entry(node, &hub->udev_list, list) {
127		if (!device_may_wakeup(node->udev->bus->controller))
128			continue;
129
130		if (usb_wakeup_enabled_descendants(node->udev)) {
131			power_off = false;
132			break;
133		}
134	}
135
136	mutex_unlock(&hub->lock);
137
138	if (!power_off)
139		return 0;
140
141	return onboard_hub_power_off(hub);
142}
143
144static int __maybe_unused onboard_hub_resume(struct device *dev)
145{
146	struct onboard_hub *hub = dev_get_drvdata(dev);
147
148	if (hub->is_powered_on)
149		return 0;
150
151	return onboard_hub_power_on(hub);
152}
153
154static inline void get_udev_link_name(const struct usb_device *udev, char *buf, size_t size)
155{
156	snprintf(buf, size, "usb_dev.%s", dev_name(&udev->dev));
157}
158
159static int onboard_hub_add_usbdev(struct onboard_hub *hub, struct usb_device *udev)
160{
161	struct usbdev_node *node;
162	char link_name[64];
163	int err;
164
165	mutex_lock(&hub->lock);
166
167	if (hub->going_away) {
168		err = -EINVAL;
169		goto error;
170	}
171
172	node = kzalloc(sizeof(*node), GFP_KERNEL);
173	if (!node) {
174		err = -ENOMEM;
175		goto error;
176	}
177
178	node->udev = udev;
179
180	list_add(&node->list, &hub->udev_list);
181
182	mutex_unlock(&hub->lock);
183
184	get_udev_link_name(udev, link_name, sizeof(link_name));
185	WARN_ON(sysfs_create_link(&hub->dev->kobj, &udev->dev.kobj, link_name));
186
187	return 0;
188
189error:
190	mutex_unlock(&hub->lock);
191
192	return err;
193}
194
195static void onboard_hub_remove_usbdev(struct onboard_hub *hub, const struct usb_device *udev)
196{
197	struct usbdev_node *node;
198	char link_name[64];
199
200	get_udev_link_name(udev, link_name, sizeof(link_name));
201	sysfs_remove_link(&hub->dev->kobj, link_name);
202
203	mutex_lock(&hub->lock);
204
205	list_for_each_entry(node, &hub->udev_list, list) {
206		if (node->udev == udev) {
207			list_del(&node->list);
208			kfree(node);
209			break;
210		}
211	}
212
213	mutex_unlock(&hub->lock);
214}
215
216static ssize_t always_powered_in_suspend_show(struct device *dev, struct device_attribute *attr,
217			   char *buf)
218{
219	const struct onboard_hub *hub = dev_get_drvdata(dev);
220
221	return sysfs_emit(buf, "%d\n", hub->always_powered_in_suspend);
222}
223
224static ssize_t always_powered_in_suspend_store(struct device *dev, struct device_attribute *attr,
225			    const char *buf, size_t count)
226{
227	struct onboard_hub *hub = dev_get_drvdata(dev);
228	bool val;
229	int ret;
230
231	ret = kstrtobool(buf, &val);
232	if (ret < 0)
233		return ret;
234
235	hub->always_powered_in_suspend = val;
236
237	return count;
238}
239static DEVICE_ATTR_RW(always_powered_in_suspend);
240
241static struct attribute *onboard_hub_attrs[] = {
242	&dev_attr_always_powered_in_suspend.attr,
243	NULL,
244};
245ATTRIBUTE_GROUPS(onboard_hub);
246
247static void onboard_hub_attach_usb_driver(struct work_struct *work)
248{
249	int err;
250
251	err = driver_attach(&onboard_hub_usbdev_driver.driver);
252	if (err)
253		pr_err("Failed to attach USB driver: %pe\n", ERR_PTR(err));
254}
255
256static int onboard_hub_probe(struct platform_device *pdev)
257{
258	struct device *dev = &pdev->dev;
259	struct onboard_hub *hub;
260	unsigned int i;
261	int err;
262
263	hub = devm_kzalloc(dev, sizeof(*hub), GFP_KERNEL);
264	if (!hub)
265		return -ENOMEM;
266
267	hub->pdata = device_get_match_data(dev);
268	if (!hub->pdata)
269		return -EINVAL;
270
271	if (hub->pdata->num_supplies > MAX_SUPPLIES)
272		return dev_err_probe(dev, -EINVAL, "max %zu supplies supported!\n",
273				     MAX_SUPPLIES);
274
275	for (i = 0; i < hub->pdata->num_supplies; i++)
276		hub->supplies[i].supply = supply_names[i];
277
278	err = devm_regulator_bulk_get(dev, hub->pdata->num_supplies, hub->supplies);
279	if (err) {
280		dev_err(dev, "Failed to get regulator supplies: %pe\n", ERR_PTR(err));
281		return err;
282	}
283
284	hub->clk = devm_clk_get_optional(dev, NULL);
285	if (IS_ERR(hub->clk))
286		return dev_err_probe(dev, PTR_ERR(hub->clk), "failed to get clock\n");
287
288	hub->reset_gpio = devm_gpiod_get_optional(dev, "reset",
289						  GPIOD_OUT_HIGH);
290	if (IS_ERR(hub->reset_gpio))
291		return dev_err_probe(dev, PTR_ERR(hub->reset_gpio), "failed to get reset GPIO\n");
292
293	hub->dev = dev;
294	mutex_init(&hub->lock);
295	INIT_LIST_HEAD(&hub->udev_list);
296
297	dev_set_drvdata(dev, hub);
298
299	err = onboard_hub_power_on(hub);
300	if (err)
301		return err;
302
303	/*
304	 * The USB driver might have been detached from the USB devices by
305	 * onboard_hub_remove() (e.g. through an 'unbind' by userspace),
306	 * make sure to re-attach it if needed.
307	 *
308	 * This needs to be done deferred to avoid self-deadlocks on systems
309	 * with nested onboard hubs.
310	 */
311	schedule_work(&attach_usb_driver_work);
312
313	return 0;
314}
315
316static void onboard_hub_remove(struct platform_device *pdev)
317{
318	struct onboard_hub *hub = dev_get_drvdata(&pdev->dev);
319	struct usbdev_node *node;
320	struct usb_device *udev;
321
322	hub->going_away = true;
323
324	mutex_lock(&hub->lock);
325
326	/* unbind the USB devices to avoid dangling references to this device */
327	while (!list_empty(&hub->udev_list)) {
328		node = list_first_entry(&hub->udev_list, struct usbdev_node, list);
329		udev = node->udev;
330
331		/*
332		 * Unbinding the driver will call onboard_hub_remove_usbdev(),
333		 * which acquires hub->lock.  We must release the lock first.
334		 */
335		get_device(&udev->dev);
336		mutex_unlock(&hub->lock);
337		device_release_driver(&udev->dev);
338		put_device(&udev->dev);
339		mutex_lock(&hub->lock);
340	}
341
342	mutex_unlock(&hub->lock);
343
344	onboard_hub_power_off(hub);
345}
346
347MODULE_DEVICE_TABLE(of, onboard_hub_match);
348
349static const struct dev_pm_ops __maybe_unused onboard_hub_pm_ops = {
350	SET_LATE_SYSTEM_SLEEP_PM_OPS(onboard_hub_suspend, onboard_hub_resume)
351};
352
353static struct platform_driver onboard_hub_driver = {
354	.probe = onboard_hub_probe,
355	.remove_new = onboard_hub_remove,
356
357	.driver = {
358		.name = "onboard-usb-hub",
359		.of_match_table = onboard_hub_match,
360		.pm = pm_ptr(&onboard_hub_pm_ops),
361		.dev_groups = onboard_hub_groups,
362	},
363};
364
365/************************** USB driver **************************/
366
367#define VENDOR_ID_CYPRESS	0x04b4
368#define VENDOR_ID_GENESYS	0x05e3
369#define VENDOR_ID_MICROCHIP	0x0424
370#define VENDOR_ID_REALTEK	0x0bda
371#define VENDOR_ID_TI		0x0451
372#define VENDOR_ID_VIA		0x2109
373
374/*
375 * Returns the onboard_hub platform device that is associated with the USB
376 * device passed as parameter.
377 */
378static struct onboard_hub *_find_onboard_hub(struct device *dev)
379{
380	struct platform_device *pdev;
381	struct device_node *np;
382	struct onboard_hub *hub;
383
384	pdev = of_find_device_by_node(dev->of_node);
385	if (!pdev) {
386		np = of_parse_phandle(dev->of_node, "peer-hub", 0);
387		if (!np) {
388			dev_err(dev, "failed to find device node for peer hub\n");
389			return ERR_PTR(-EINVAL);
390		}
391
392		pdev = of_find_device_by_node(np);
393		of_node_put(np);
394
395		if (!pdev)
396			return ERR_PTR(-ENODEV);
397	}
398
399	hub = dev_get_drvdata(&pdev->dev);
400	put_device(&pdev->dev);
401
402	/*
403	 * The presence of drvdata ('hub') indicates that the platform driver
404	 * finished probing. This handles the case where (conceivably) we could
405	 * be running at the exact same time as the platform driver's probe. If
406	 * we detect the race we request probe deferral and we'll come back and
407	 * try again.
408	 */
409	if (!hub)
410		return ERR_PTR(-EPROBE_DEFER);
411
412	return hub;
413}
414
415static int onboard_hub_usbdev_probe(struct usb_device *udev)
416{
417	struct device *dev = &udev->dev;
418	struct onboard_hub *hub;
419	int err;
420
421	/* ignore supported hubs without device tree node */
422	if (!dev->of_node)
423		return -ENODEV;
424
425	hub = _find_onboard_hub(dev);
426	if (IS_ERR(hub))
427		return PTR_ERR(hub);
428
429	dev_set_drvdata(dev, hub);
430
431	err = onboard_hub_add_usbdev(hub, udev);
432	if (err)
433		return err;
434
435	return 0;
436}
437
438static void onboard_hub_usbdev_disconnect(struct usb_device *udev)
439{
440	struct onboard_hub *hub = dev_get_drvdata(&udev->dev);
441
442	onboard_hub_remove_usbdev(hub, udev);
443}
444
445static const struct usb_device_id onboard_hub_id_table[] = {
446	{ USB_DEVICE(VENDOR_ID_CYPRESS, 0x6504) }, /* CYUSB33{0,1,2}x/CYUSB230x 3.0 */
447	{ USB_DEVICE(VENDOR_ID_CYPRESS, 0x6506) }, /* CYUSB33{0,1,2}x/CYUSB230x 2.0 */
448	{ USB_DEVICE(VENDOR_ID_CYPRESS, 0x6570) }, /* CY7C6563x 2.0 */
449	{ USB_DEVICE(VENDOR_ID_GENESYS, 0x0608) }, /* Genesys Logic GL850G USB 2.0 */
450	{ USB_DEVICE(VENDOR_ID_GENESYS, 0x0610) }, /* Genesys Logic GL852G USB 2.0 */
451	{ USB_DEVICE(VENDOR_ID_GENESYS, 0x0620) }, /* Genesys Logic GL3523 USB 3.1 */
452	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2412) }, /* USB2412 USB 2.0 */
453	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2514) }, /* USB2514B USB 2.0 */
454	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2517) }, /* USB2517 USB 2.0 */
455	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2744) }, /* USB5744 USB 2.0 */
456	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x5744) }, /* USB5744 USB 3.0 */
457	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x0411) }, /* RTS5411 USB 3.1 */
458	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x5411) }, /* RTS5411 USB 2.1 */
459	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x0414) }, /* RTS5414 USB 3.2 */
460	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x5414) }, /* RTS5414 USB 2.1 */
461	{ USB_DEVICE(VENDOR_ID_TI, 0x8025) }, /* TI USB8020B 3.0 */
462	{ USB_DEVICE(VENDOR_ID_TI, 0x8027) }, /* TI USB8020B 2.0 */
463	{ USB_DEVICE(VENDOR_ID_TI, 0x8140) }, /* TI USB8041 3.0 */
464	{ USB_DEVICE(VENDOR_ID_TI, 0x8142) }, /* TI USB8041 2.0 */
465	{ USB_DEVICE(VENDOR_ID_VIA, 0x0817) }, /* VIA VL817 3.1 */
466	{ USB_DEVICE(VENDOR_ID_VIA, 0x2817) }, /* VIA VL817 2.0 */
467	{}
468};
469MODULE_DEVICE_TABLE(usb, onboard_hub_id_table);
470
471static struct usb_device_driver onboard_hub_usbdev_driver = {
472	.name = "onboard-usb-hub",
473	.probe = onboard_hub_usbdev_probe,
474	.disconnect = onboard_hub_usbdev_disconnect,
475	.generic_subclass = 1,
476	.supports_autosuspend =	1,
477	.id_table = onboard_hub_id_table,
478};
479
480static int __init onboard_hub_init(void)
481{
482	int ret;
483
484	ret = usb_register_device_driver(&onboard_hub_usbdev_driver, THIS_MODULE);
485	if (ret)
486		return ret;
487
488	ret = platform_driver_register(&onboard_hub_driver);
489	if (ret)
490		usb_deregister_device_driver(&onboard_hub_usbdev_driver);
491
492	return ret;
493}
494module_init(onboard_hub_init);
495
496static void __exit onboard_hub_exit(void)
497{
498	usb_deregister_device_driver(&onboard_hub_usbdev_driver);
499	platform_driver_unregister(&onboard_hub_driver);
500
501	cancel_work_sync(&attach_usb_driver_work);
502}
503module_exit(onboard_hub_exit);
504
505MODULE_AUTHOR("Matthias Kaehlcke <mka@chromium.org>");
506MODULE_DESCRIPTION("Driver for discrete onboard USB hubs");
507MODULE_LICENSE("GPL v2");
508