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