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 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 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 } 115 116 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 } 125 126 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 } 130 131 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 } 166 167 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 } 187 188 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 } 195 196 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); 218 219 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 } 227 228 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 } 279 280 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 */ 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 } 378 379 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 } 401 402 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 }; 429 430 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); 445 446 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