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 void onboard_hub_attach_usb_driver(struct work_struct *work); 31 32 static struct usb_device_driver onboard_hub_usbdev_driver; 33 static DECLARE_WORK(attach_usb_driver_work, onboard_hub_attach_usb_driver); 34 35 /************************** Platform driver **************************/ 36 37 struct usbdev_node { 38 struct usb_device *udev; 39 struct list_head list; 40 }; 41 42 struct onboard_hub { 43 struct regulator *vdd; 44 struct device *dev; 45 const struct onboard_hub_pdata *pdata; 46 struct gpio_desc *reset_gpio; 47 bool always_powered_in_suspend; 48 bool is_powered_on; 49 bool going_away; 50 struct list_head udev_list; 51 struct mutex lock; 52 }; 53 54 static int onboard_hub_power_on(struct onboard_hub *hub) 55 { 56 int err; 57 58 err = regulator_enable(hub->vdd); 59 if (err) { 60 dev_err(hub->dev, "failed to enable regulator: %d\n", err); 61 return err; 62 } 63 64 fsleep(hub->pdata->reset_us); 65 gpiod_set_value_cansleep(hub->reset_gpio, 0); 66 67 hub->is_powered_on = true; 68 69 return 0; 70 } 71 72 static int onboard_hub_power_off(struct onboard_hub *hub) 73 { 74 int err; 75 76 gpiod_set_value_cansleep(hub->reset_gpio, 1); 77 78 err = regulator_disable(hub->vdd); 79 if (err) { 80 dev_err(hub->dev, "failed to disable regulator: %d\n", err); 81 return err; 82 } 83 84 hub->is_powered_on = false; 85 86 return 0; 87 } 88 89 static int __maybe_unused onboard_hub_suspend(struct device *dev) 90 { 91 struct onboard_hub *hub = dev_get_drvdata(dev); 92 struct usbdev_node *node; 93 bool power_off = true; 94 95 if (hub->always_powered_in_suspend) 96 return 0; 97 98 mutex_lock(&hub->lock); 99 100 list_for_each_entry(node, &hub->udev_list, list) { 101 if (!device_may_wakeup(node->udev->bus->controller)) 102 continue; 103 104 if (usb_wakeup_enabled_descendants(node->udev)) { 105 power_off = false; 106 break; 107 } 108 } 109 110 mutex_unlock(&hub->lock); 111 112 if (!power_off) 113 return 0; 114 115 return onboard_hub_power_off(hub); 116 } 117 118 static int __maybe_unused onboard_hub_resume(struct device *dev) 119 { 120 struct onboard_hub *hub = dev_get_drvdata(dev); 121 122 if (hub->is_powered_on) 123 return 0; 124 125 return onboard_hub_power_on(hub); 126 } 127 128 static inline void get_udev_link_name(const struct usb_device *udev, char *buf, size_t size) 129 { 130 snprintf(buf, size, "usb_dev.%s", dev_name(&udev->dev)); 131 } 132 133 static int onboard_hub_add_usbdev(struct onboard_hub *hub, struct usb_device *udev) 134 { 135 struct usbdev_node *node; 136 char link_name[64]; 137 int err; 138 139 mutex_lock(&hub->lock); 140 141 if (hub->going_away) { 142 err = -EINVAL; 143 goto error; 144 } 145 146 node = kzalloc(sizeof(*node), GFP_KERNEL); 147 if (!node) { 148 err = -ENOMEM; 149 goto error; 150 } 151 152 node->udev = udev; 153 154 list_add(&node->list, &hub->udev_list); 155 156 mutex_unlock(&hub->lock); 157 158 get_udev_link_name(udev, link_name, sizeof(link_name)); 159 WARN_ON(sysfs_create_link(&hub->dev->kobj, &udev->dev.kobj, link_name)); 160 161 return 0; 162 163 error: 164 mutex_unlock(&hub->lock); 165 166 return err; 167 } 168 169 static void onboard_hub_remove_usbdev(struct onboard_hub *hub, const struct usb_device *udev) 170 { 171 struct usbdev_node *node; 172 char link_name[64]; 173 174 get_udev_link_name(udev, link_name, sizeof(link_name)); 175 sysfs_remove_link(&hub->dev->kobj, link_name); 176 177 mutex_lock(&hub->lock); 178 179 list_for_each_entry(node, &hub->udev_list, list) { 180 if (node->udev == udev) { 181 list_del(&node->list); 182 kfree(node); 183 break; 184 } 185 } 186 187 mutex_unlock(&hub->lock); 188 } 189 190 static ssize_t always_powered_in_suspend_show(struct device *dev, struct device_attribute *attr, 191 char *buf) 192 { 193 const struct onboard_hub *hub = dev_get_drvdata(dev); 194 195 return sysfs_emit(buf, "%d\n", hub->always_powered_in_suspend); 196 } 197 198 static ssize_t always_powered_in_suspend_store(struct device *dev, struct device_attribute *attr, 199 const char *buf, size_t count) 200 { 201 struct onboard_hub *hub = dev_get_drvdata(dev); 202 bool val; 203 int ret; 204 205 ret = kstrtobool(buf, &val); 206 if (ret < 0) 207 return ret; 208 209 hub->always_powered_in_suspend = val; 210 211 return count; 212 } 213 static DEVICE_ATTR_RW(always_powered_in_suspend); 214 215 static struct attribute *onboard_hub_attrs[] = { 216 &dev_attr_always_powered_in_suspend.attr, 217 NULL, 218 }; 219 ATTRIBUTE_GROUPS(onboard_hub); 220 221 static void onboard_hub_attach_usb_driver(struct work_struct *work) 222 { 223 int err; 224 225 err = driver_attach(&onboard_hub_usbdev_driver.drvwrap.driver); 226 if (err) 227 pr_err("Failed to attach USB driver: %d\n", err); 228 } 229 230 static int onboard_hub_probe(struct platform_device *pdev) 231 { 232 const struct of_device_id *of_id; 233 struct device *dev = &pdev->dev; 234 struct onboard_hub *hub; 235 int err; 236 237 hub = devm_kzalloc(dev, sizeof(*hub), GFP_KERNEL); 238 if (!hub) 239 return -ENOMEM; 240 241 of_id = of_match_device(onboard_hub_match, &pdev->dev); 242 if (!of_id) 243 return -ENODEV; 244 245 hub->pdata = of_id->data; 246 if (!hub->pdata) 247 return -EINVAL; 248 249 hub->vdd = devm_regulator_get(dev, "vdd"); 250 if (IS_ERR(hub->vdd)) 251 return PTR_ERR(hub->vdd); 252 253 hub->reset_gpio = devm_gpiod_get_optional(dev, "reset", 254 GPIOD_OUT_HIGH); 255 if (IS_ERR(hub->reset_gpio)) 256 return dev_err_probe(dev, PTR_ERR(hub->reset_gpio), "failed to get reset GPIO\n"); 257 258 hub->dev = dev; 259 mutex_init(&hub->lock); 260 INIT_LIST_HEAD(&hub->udev_list); 261 262 dev_set_drvdata(dev, hub); 263 264 err = onboard_hub_power_on(hub); 265 if (err) 266 return err; 267 268 /* 269 * The USB driver might have been detached from the USB devices by 270 * onboard_hub_remove() (e.g. through an 'unbind' by userspace), 271 * make sure to re-attach it if needed. 272 * 273 * This needs to be done deferred to avoid self-deadlocks on systems 274 * with nested onboard hubs. 275 */ 276 schedule_work(&attach_usb_driver_work); 277 278 return 0; 279 } 280 281 static int onboard_hub_remove(struct platform_device *pdev) 282 { 283 struct onboard_hub *hub = dev_get_drvdata(&pdev->dev); 284 struct usbdev_node *node; 285 struct usb_device *udev; 286 287 hub->going_away = true; 288 289 mutex_lock(&hub->lock); 290 291 /* unbind the USB devices to avoid dangling references to this device */ 292 while (!list_empty(&hub->udev_list)) { 293 node = list_first_entry(&hub->udev_list, struct usbdev_node, list); 294 udev = node->udev; 295 296 /* 297 * Unbinding the driver will call onboard_hub_remove_usbdev(), 298 * which acquires hub->lock. We must release the lock first. 299 */ 300 get_device(&udev->dev); 301 mutex_unlock(&hub->lock); 302 device_release_driver(&udev->dev); 303 put_device(&udev->dev); 304 mutex_lock(&hub->lock); 305 } 306 307 mutex_unlock(&hub->lock); 308 309 return onboard_hub_power_off(hub); 310 } 311 312 MODULE_DEVICE_TABLE(of, onboard_hub_match); 313 314 static const struct dev_pm_ops __maybe_unused onboard_hub_pm_ops = { 315 SET_LATE_SYSTEM_SLEEP_PM_OPS(onboard_hub_suspend, onboard_hub_resume) 316 }; 317 318 static struct platform_driver onboard_hub_driver = { 319 .probe = onboard_hub_probe, 320 .remove = onboard_hub_remove, 321 322 .driver = { 323 .name = "onboard-usb-hub", 324 .of_match_table = onboard_hub_match, 325 .pm = pm_ptr(&onboard_hub_pm_ops), 326 .dev_groups = onboard_hub_groups, 327 }, 328 }; 329 330 /************************** USB driver **************************/ 331 332 #define VENDOR_ID_GENESYS 0x05e3 333 #define VENDOR_ID_MICROCHIP 0x0424 334 #define VENDOR_ID_REALTEK 0x0bda 335 #define VENDOR_ID_TI 0x0451 336 #define VENDOR_ID_VIA 0x2109 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_GENESYS, 0x0608) }, /* Genesys Logic GL850G USB 2.0 */ 411 { USB_DEVICE(VENDOR_ID_GENESYS, 0x0610) }, /* Genesys Logic GL852G USB 2.0 */ 412 { USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2514) }, /* USB2514B USB 2.0 */ 413 { USB_DEVICE(VENDOR_ID_REALTEK, 0x0411) }, /* RTS5411 USB 3.1 */ 414 { USB_DEVICE(VENDOR_ID_REALTEK, 0x5411) }, /* RTS5411 USB 2.1 */ 415 { USB_DEVICE(VENDOR_ID_REALTEK, 0x0414) }, /* RTS5414 USB 3.2 */ 416 { USB_DEVICE(VENDOR_ID_REALTEK, 0x5414) }, /* RTS5414 USB 2.1 */ 417 { USB_DEVICE(VENDOR_ID_TI, 0x8140) }, /* TI USB8041 3.0 */ 418 { USB_DEVICE(VENDOR_ID_TI, 0x8142) }, /* TI USB8041 2.0 */ 419 { USB_DEVICE(VENDOR_ID_VIA, 0x0817) }, /* VIA VL817 3.1 */ 420 { USB_DEVICE(VENDOR_ID_VIA, 0x2817) }, /* VIA VL817 2.0 */ 421 {} 422 }; 423 MODULE_DEVICE_TABLE(usb, onboard_hub_id_table); 424 425 static struct usb_device_driver onboard_hub_usbdev_driver = { 426 .name = "onboard-usb-hub", 427 .probe = onboard_hub_usbdev_probe, 428 .disconnect = onboard_hub_usbdev_disconnect, 429 .generic_subclass = 1, 430 .supports_autosuspend = 1, 431 .id_table = onboard_hub_id_table, 432 }; 433 434 static int __init onboard_hub_init(void) 435 { 436 int ret; 437 438 ret = usb_register_device_driver(&onboard_hub_usbdev_driver, THIS_MODULE); 439 if (ret) 440 return ret; 441 442 ret = platform_driver_register(&onboard_hub_driver); 443 if (ret) 444 usb_deregister_device_driver(&onboard_hub_usbdev_driver); 445 446 return ret; 447 } 448 module_init(onboard_hub_init); 449 450 static void __exit onboard_hub_exit(void) 451 { 452 usb_deregister_device_driver(&onboard_hub_usbdev_driver); 453 platform_driver_unregister(&onboard_hub_driver); 454 455 cancel_work_sync(&attach_usb_driver_work); 456 } 457 module_exit(onboard_hub_exit); 458 459 MODULE_AUTHOR("Matthias Kaehlcke <mka@chromium.org>"); 460 MODULE_DESCRIPTION("Driver for discrete onboard USB hubs"); 461 MODULE_LICENSE("GPL v2"); 462