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 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 70 static int onboard_hub_power_off(struct onboard_hub *hub) 71 { 72 int err; 73 74 if (hub->reset_gpio) { 75 gpiod_set_value_cansleep(hub->reset_gpio, 1); 76 fsleep(hub->pdata->reset_us); 77 } 78 79 err = regulator_disable(hub->vdd); 80 if (err) { 81 dev_err(hub->dev, "failed to disable regulator: %d\n", err); 82 return err; 83 } 84 85 hub->is_powered_on = false; 86 87 return 0; 88 } 89 90 static int __maybe_unused onboard_hub_suspend(struct device *dev) 91 { 92 struct onboard_hub *hub = dev_get_drvdata(dev); 93 struct usbdev_node *node; 94 bool power_off = true; 95 96 if (hub->always_powered_in_suspend) 97 return 0; 98 99 mutex_lock(&hub->lock); 100 101 list_for_each_entry(node, &hub->udev_list, list) { 102 if (!device_may_wakeup(node->udev->bus->controller)) 103 continue; 104 105 if (usb_wakeup_enabled_descendants(node->udev)) { 106 power_off = false; 107 break; 108 } 109 } 110 111 mutex_unlock(&hub->lock); 112 113 if (!power_off) 114 return 0; 115 116 return onboard_hub_power_off(hub); 117 } 118 119 static int __maybe_unused onboard_hub_resume(struct device *dev) 120 { 121 struct onboard_hub *hub = dev_get_drvdata(dev); 122 123 if (hub->is_powered_on) 124 return 0; 125 126 return onboard_hub_power_on(hub); 127 } 128 129 static inline void get_udev_link_name(const struct usb_device *udev, char *buf, size_t size) 130 { 131 snprintf(buf, size, "usb_dev.%s", dev_name(&udev->dev)); 132 } 133 134 static int onboard_hub_add_usbdev(struct onboard_hub *hub, struct usb_device *udev) 135 { 136 struct usbdev_node *node; 137 char link_name[64]; 138 int err; 139 140 mutex_lock(&hub->lock); 141 142 if (hub->going_away) { 143 err = -EINVAL; 144 goto error; 145 } 146 147 node = kzalloc(sizeof(*node), GFP_KERNEL); 148 if (!node) { 149 err = -ENOMEM; 150 goto error; 151 } 152 153 node->udev = udev; 154 155 list_add(&node->list, &hub->udev_list); 156 157 mutex_unlock(&hub->lock); 158 159 get_udev_link_name(udev, link_name, sizeof(link_name)); 160 WARN_ON(sysfs_create_link(&hub->dev->kobj, &udev->dev.kobj, link_name)); 161 162 return 0; 163 164 error: 165 mutex_unlock(&hub->lock); 166 167 return err; 168 } 169 170 static void onboard_hub_remove_usbdev(struct onboard_hub *hub, const struct usb_device *udev) 171 { 172 struct usbdev_node *node; 173 char link_name[64]; 174 175 get_udev_link_name(udev, link_name, sizeof(link_name)); 176 sysfs_remove_link(&hub->dev->kobj, link_name); 177 178 mutex_lock(&hub->lock); 179 180 list_for_each_entry(node, &hub->udev_list, list) { 181 if (node->udev == udev) { 182 list_del(&node->list); 183 kfree(node); 184 break; 185 } 186 } 187 188 mutex_unlock(&hub->lock); 189 } 190 191 static ssize_t always_powered_in_suspend_show(struct device *dev, struct device_attribute *attr, 192 char *buf) 193 { 194 const struct onboard_hub *hub = dev_get_drvdata(dev); 195 196 return sysfs_emit(buf, "%d\n", hub->always_powered_in_suspend); 197 } 198 199 static ssize_t always_powered_in_suspend_store(struct device *dev, struct device_attribute *attr, 200 const char *buf, size_t count) 201 { 202 struct onboard_hub *hub = dev_get_drvdata(dev); 203 bool val; 204 int ret; 205 206 ret = kstrtobool(buf, &val); 207 if (ret < 0) 208 return ret; 209 210 hub->always_powered_in_suspend = val; 211 212 return count; 213 } 214 static DEVICE_ATTR_RW(always_powered_in_suspend); 215 216 static struct attribute *onboard_hub_attrs[] = { 217 &dev_attr_always_powered_in_suspend.attr, 218 NULL, 219 }; 220 ATTRIBUTE_GROUPS(onboard_hub); 221 222 static void onboard_hub_attach_usb_driver(struct work_struct *work) 223 { 224 int err; 225 226 err = driver_attach(&onboard_hub_usbdev_driver.drvwrap.driver); 227 if (err) 228 pr_err("Failed to attach USB driver: %d\n", err); 229 } 230 231 static int onboard_hub_probe(struct platform_device *pdev) 232 { 233 const struct of_device_id *of_id; 234 struct device *dev = &pdev->dev; 235 struct onboard_hub *hub; 236 int err; 237 238 hub = devm_kzalloc(dev, sizeof(*hub), GFP_KERNEL); 239 if (!hub) 240 return -ENOMEM; 241 242 of_id = of_match_device(onboard_hub_match, &pdev->dev); 243 if (!of_id) 244 return -ENODEV; 245 246 hub->pdata = of_id->data; 247 if (!hub->pdata) 248 return -EINVAL; 249 250 hub->vdd = devm_regulator_get(dev, "vdd"); 251 if (IS_ERR(hub->vdd)) 252 return PTR_ERR(hub->vdd); 253 254 hub->reset_gpio = devm_gpiod_get_optional(dev, "reset", 255 GPIOD_OUT_HIGH); 256 if (IS_ERR(hub->reset_gpio)) 257 return dev_err_probe(dev, PTR_ERR(hub->reset_gpio), "failed to get reset GPIO\n"); 258 259 hub->dev = dev; 260 mutex_init(&hub->lock); 261 INIT_LIST_HEAD(&hub->udev_list); 262 263 dev_set_drvdata(dev, hub); 264 265 err = onboard_hub_power_on(hub); 266 if (err) 267 return err; 268 269 /* 270 * The USB driver might have been detached from the USB devices by 271 * onboard_hub_remove() (e.g. through an 'unbind' by userspace), 272 * make sure to re-attach it if needed. 273 * 274 * This needs to be done deferred to avoid self-deadlocks on systems 275 * with nested onboard hubs. 276 */ 277 INIT_WORK(&hub->attach_usb_driver_work, onboard_hub_attach_usb_driver); 278 schedule_work(&hub->attach_usb_driver_work); 279 280 return 0; 281 } 282 283 static int onboard_hub_remove(struct platform_device *pdev) 284 { 285 struct onboard_hub *hub = dev_get_drvdata(&pdev->dev); 286 struct usbdev_node *node; 287 struct usb_device *udev; 288 289 hub->going_away = true; 290 291 if (&hub->attach_usb_driver_work != current_work()) 292 cancel_work_sync(&hub->attach_usb_driver_work); 293 294 mutex_lock(&hub->lock); 295 296 /* unbind the USB devices to avoid dangling references to this device */ 297 while (!list_empty(&hub->udev_list)) { 298 node = list_first_entry(&hub->udev_list, struct usbdev_node, list); 299 udev = node->udev; 300 301 /* 302 * Unbinding the driver will call onboard_hub_remove_usbdev(), 303 * which acquires hub->lock. We must release the lock first. 304 */ 305 get_device(&udev->dev); 306 mutex_unlock(&hub->lock); 307 device_release_driver(&udev->dev); 308 put_device(&udev->dev); 309 mutex_lock(&hub->lock); 310 } 311 312 mutex_unlock(&hub->lock); 313 314 return onboard_hub_power_off(hub); 315 } 316 317 MODULE_DEVICE_TABLE(of, onboard_hub_match); 318 319 static const struct dev_pm_ops __maybe_unused onboard_hub_pm_ops = { 320 SET_LATE_SYSTEM_SLEEP_PM_OPS(onboard_hub_suspend, onboard_hub_resume) 321 }; 322 323 static struct platform_driver onboard_hub_driver = { 324 .probe = onboard_hub_probe, 325 .remove = onboard_hub_remove, 326 327 .driver = { 328 .name = "onboard-usb-hub", 329 .of_match_table = onboard_hub_match, 330 .pm = pm_ptr(&onboard_hub_pm_ops), 331 .dev_groups = onboard_hub_groups, 332 }, 333 }; 334 335 /************************** USB driver **************************/ 336 337 #define VENDOR_ID_MICROCHIP 0x0424 338 #define VENDOR_ID_REALTEK 0x0bda 339 #define VENDOR_ID_TI 0x0451 340 341 /* 342 * Returns the onboard_hub platform device that is associated with the USB 343 * device passed as parameter. 344 */ 345 static struct onboard_hub *_find_onboard_hub(struct device *dev) 346 { 347 struct platform_device *pdev; 348 struct device_node *np; 349 struct onboard_hub *hub; 350 351 pdev = of_find_device_by_node(dev->of_node); 352 if (!pdev) { 353 np = of_parse_phandle(dev->of_node, "peer-hub", 0); 354 if (!np) { 355 dev_err(dev, "failed to find device node for peer hub\n"); 356 return ERR_PTR(-EINVAL); 357 } 358 359 pdev = of_find_device_by_node(np); 360 of_node_put(np); 361 362 if (!pdev) 363 return ERR_PTR(-ENODEV); 364 } 365 366 hub = dev_get_drvdata(&pdev->dev); 367 put_device(&pdev->dev); 368 369 /* 370 * The presence of drvdata ('hub') indicates that the platform driver 371 * finished probing. This handles the case where (conceivably) we could 372 * be running at the exact same time as the platform driver's probe. If 373 * we detect the race we request probe deferral and we'll come back and 374 * try again. 375 */ 376 if (!hub) 377 return ERR_PTR(-EPROBE_DEFER); 378 379 return hub; 380 } 381 382 static int onboard_hub_usbdev_probe(struct usb_device *udev) 383 { 384 struct device *dev = &udev->dev; 385 struct onboard_hub *hub; 386 int err; 387 388 /* ignore supported hubs without device tree node */ 389 if (!dev->of_node) 390 return -ENODEV; 391 392 hub = _find_onboard_hub(dev); 393 if (IS_ERR(hub)) 394 return PTR_ERR(hub); 395 396 dev_set_drvdata(dev, hub); 397 398 err = onboard_hub_add_usbdev(hub, udev); 399 if (err) 400 return err; 401 402 return 0; 403 } 404 405 static void onboard_hub_usbdev_disconnect(struct usb_device *udev) 406 { 407 struct onboard_hub *hub = dev_get_drvdata(&udev->dev); 408 409 onboard_hub_remove_usbdev(hub, udev); 410 } 411 412 static const struct usb_device_id onboard_hub_id_table[] = { 413 { USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2514) }, /* USB2514B USB 2.0 */ 414 { USB_DEVICE(VENDOR_ID_REALTEK, 0x0411) }, /* RTS5411 USB 3.1 */ 415 { USB_DEVICE(VENDOR_ID_REALTEK, 0x5411) }, /* RTS5411 USB 2.1 */ 416 { USB_DEVICE(VENDOR_ID_REALTEK, 0x0414) }, /* RTS5414 USB 3.2 */ 417 { USB_DEVICE(VENDOR_ID_REALTEK, 0x5414) }, /* RTS5414 USB 2.1 */ 418 { USB_DEVICE(VENDOR_ID_TI, 0x8140) }, /* TI USB8041 3.0 */ 419 { USB_DEVICE(VENDOR_ID_TI, 0x8142) }, /* TI USB8041 2.0 */ 420 {} 421 }; 422 MODULE_DEVICE_TABLE(usb, onboard_hub_id_table); 423 424 static struct usb_device_driver onboard_hub_usbdev_driver = { 425 .name = "onboard-usb-hub", 426 .probe = onboard_hub_usbdev_probe, 427 .disconnect = onboard_hub_usbdev_disconnect, 428 .generic_subclass = 1, 429 .supports_autosuspend = 1, 430 .id_table = onboard_hub_id_table, 431 }; 432 433 static int __init onboard_hub_init(void) 434 { 435 int ret; 436 437 ret = platform_driver_register(&onboard_hub_driver); 438 if (ret) 439 return ret; 440 441 ret = usb_register_device_driver(&onboard_hub_usbdev_driver, THIS_MODULE); 442 if (ret) 443 platform_driver_unregister(&onboard_hub_driver); 444 445 return ret; 446 } 447 module_init(onboard_hub_init); 448 449 static void __exit onboard_hub_exit(void) 450 { 451 usb_deregister_device_driver(&onboard_hub_usbdev_driver); 452 platform_driver_unregister(&onboard_hub_driver); 453 } 454 module_exit(onboard_hub_exit); 455 456 MODULE_AUTHOR("Matthias Kaehlcke <mka@chromium.org>"); 457 MODULE_DESCRIPTION("Driver for discrete onboard USB hubs"); 458 MODULE_LICENSE("GPL v2"); 459