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
32static void onboard_dev_attach_usb_driver(struct work_struct *work);
33
34static struct usb_device_driver onboard_dev_usbdev_driver;
35static DECLARE_WORK(attach_usb_driver_work, onboard_dev_attach_usb_driver);
36
37/************************** Platform driver **************************/
38
39struct usbdev_node {
40	struct usb_device *udev;
41	struct list_head list;
42};
43
44struct 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
57static 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
80static 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
106disable_clk:
107	clk_disable_unprepare(onboard_dev->clk);
108	return err;
109}
110
111static 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
132static 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
161static 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
171static 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
177static 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
209error:
210	mutex_unlock(&onboard_dev->lock);
211
212	return err;
213}
214
215static 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
237static 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
246static 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}
262static DEVICE_ATTR_RW(always_powered_in_suspend);
263
264static struct attribute *onboard_dev_attrs[] = {
265	&dev_attr_always_powered_in_suspend.attr,
266	NULL,
267};
268
269static 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
283static 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
290static 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
299static 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
355static 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
388MODULE_DEVICE_TABLE(of, onboard_dev_match);
389
390static 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
394static 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 */
420static 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
457static int onboard_dev_usbdev_probe(struct usb_device *udev)
458{
459	struct device *dev = &udev->dev;
460	struct onboard_dev *onboard_dev;
461	int err;
462
463	/* ignore supported devices without device tree node */
464	if (!dev->of_node)
465		return -ENODEV;
466
467	onboard_dev = _find_onboard_dev(dev);
468	if (IS_ERR(onboard_dev))
469		return PTR_ERR(onboard_dev);
470
471	dev_set_drvdata(dev, onboard_dev);
472
473	err = onboard_dev_add_usbdev(onboard_dev, udev);
474	if (err)
475		return err;
476
477	return 0;
478}
479
480static void onboard_dev_usbdev_disconnect(struct usb_device *udev)
481{
482	struct onboard_dev *onboard_dev = dev_get_drvdata(&udev->dev);
483
484	onboard_dev_remove_usbdev(onboard_dev, udev);
485}
486
487static const struct usb_device_id onboard_dev_id_table[] = {
488	{ USB_DEVICE(VENDOR_ID_CYPRESS, 0x6504) }, /* CYUSB33{0,1,2}x/CYUSB230x 3.0 HUB */
489	{ USB_DEVICE(VENDOR_ID_CYPRESS, 0x6506) }, /* CYUSB33{0,1,2}x/CYUSB230x 2.0 HUB */
490	{ USB_DEVICE(VENDOR_ID_CYPRESS, 0x6570) }, /* CY7C6563x 2.0 HUB */
491	{ USB_DEVICE(VENDOR_ID_GENESYS, 0x0608) }, /* Genesys Logic GL850G USB 2.0 HUB */
492	{ USB_DEVICE(VENDOR_ID_GENESYS, 0x0610) }, /* Genesys Logic GL852G USB 2.0 HUB */
493	{ USB_DEVICE(VENDOR_ID_GENESYS, 0x0620) }, /* Genesys Logic GL3523 USB 3.1 HUB */
494	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2412) }, /* USB2412 USB 2.0 HUB */
495	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2514) }, /* USB2514B USB 2.0 HUB */
496	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2517) }, /* USB2517 USB 2.0 HUB */
497	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2744) }, /* USB5744 USB 2.0 HUB */
498	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x5744) }, /* USB5744 USB 3.0 HUB */
499	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x0411) }, /* RTS5411 USB 3.1 HUB */
500	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x5411) }, /* RTS5411 USB 2.1 HUB */
501	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x0414) }, /* RTS5414 USB 3.2 HUB */
502	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x5414) }, /* RTS5414 USB 2.1 HUB */
503	{ USB_DEVICE(VENDOR_ID_TI, 0x8025) }, /* TI USB8020B 3.0 HUB */
504	{ USB_DEVICE(VENDOR_ID_TI, 0x8027) }, /* TI USB8020B 2.0 HUB */
505	{ USB_DEVICE(VENDOR_ID_TI, 0x8140) }, /* TI USB8041 3.0 HUB */
506	{ USB_DEVICE(VENDOR_ID_TI, 0x8142) }, /* TI USB8041 2.0 HUB */
507	{ USB_DEVICE(VENDOR_ID_VIA, 0x0817) }, /* VIA VL817 3.1 HUB */
508	{ USB_DEVICE(VENDOR_ID_VIA, 0x2817) }, /* VIA VL817 2.0 HUB */
509	{ USB_DEVICE(VENDOR_ID_XMOS, 0x0013) }, /* XMOS XVF3500 Voice Processor */
510	{}
511};
512MODULE_DEVICE_TABLE(usb, onboard_dev_id_table);
513
514static struct usb_device_driver onboard_dev_usbdev_driver = {
515	.name = "onboard-usb-dev",
516	.probe = onboard_dev_usbdev_probe,
517	.disconnect = onboard_dev_usbdev_disconnect,
518	.generic_subclass = 1,
519	.supports_autosuspend =	1,
520	.id_table = onboard_dev_id_table,
521};
522
523static int __init onboard_dev_init(void)
524{
525	int ret;
526
527	ret = usb_register_device_driver(&onboard_dev_usbdev_driver, THIS_MODULE);
528	if (ret)
529		return ret;
530
531	ret = platform_driver_register(&onboard_dev_driver);
532	if (ret)
533		usb_deregister_device_driver(&onboard_dev_usbdev_driver);
534
535	return ret;
536}
537module_init(onboard_dev_init);
538
539static void __exit onboard_dev_exit(void)
540{
541	usb_deregister_device_driver(&onboard_dev_usbdev_driver);
542	platform_driver_unregister(&onboard_dev_driver);
543
544	cancel_work_sync(&attach_usb_driver_work);
545}
546module_exit(onboard_dev_exit);
547
548MODULE_AUTHOR("Matthias Kaehlcke <mka@chromium.org>");
549MODULE_DESCRIPTION("Driver for discrete onboard USB devices");
550MODULE_LICENSE("GPL v2");
551