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