drivers/tty/serdev/core.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2016-2017 Linaro Ltd., Rob Herring <robh@kernel.org>
   4  *
   5  * Based on drivers/spmi/spmi.c:
   6  * Copyright (c) 2012-2015, The Linux Foundation. All rights reserved.
   7  */
   8
   9 #include <linux/acpi.h>
  10 #include <linux/errno.h>
  11 #include <linux/idr.h>
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/of.h>
  15 #include <linux/of_device.h>
  16 #include <linux/pm_domain.h>
  17 #include <linux/pm_runtime.h>
  18 #include <linux/sched.h>
  19 #include <linux/serdev.h>
  20 #include <linux/slab.h>
  21
  22 static bool is_registered;
  23 static DEFINE_IDA(ctrl_ida);
  24
  25 static ssize_t modalias_show(struct device *dev,
  26                              struct device_attribute *attr, char *buf)
  27 {
  28         int len;
  29
  30         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  31         if (len != -ENODEV)
  32                 return len;
  33
  34         return of_device_modalias(dev, buf, PAGE_SIZE);
  35 }
  36 static DEVICE_ATTR_RO(modalias);
  37
  38 static struct attribute *serdev_device_attrs[] = {
  39         &dev_attr_modalias.attr,
  40         NULL,
  41 };
  42 ATTRIBUTE_GROUPS(serdev_device);
  43
  44 static int serdev_device_uevent(struct device *dev, struct kobj_uevent_env *env)
  45 {
  46         int rc;
  47
  48         /* TODO: platform modalias */
  49
  50         rc = acpi_device_uevent_modalias(dev, env);
  51         if (rc != -ENODEV)
  52                 return rc;
  53
  54         return of_device_uevent_modalias(dev, env);
  55 }
  56
  57 static void serdev_device_release(struct device *dev)
  58 {
  59         struct serdev_device *serdev = to_serdev_device(dev);
  60         kfree(serdev);
  61 }
  62
  63 static const struct device_type serdev_device_type = {
  64         .groups         = serdev_device_groups,
  65         .uevent         = serdev_device_uevent,
  66         .release        = serdev_device_release,
  67 };
  68
  69 static bool is_serdev_device(const struct device *dev)
  70 {
  71         return dev->type == &serdev_device_type;
  72 }
  73
  74 static void serdev_ctrl_release(struct device *dev)
  75 {
  76         struct serdev_controller *ctrl = to_serdev_controller(dev);
  77         ida_simple_remove(&ctrl_ida, ctrl->nr);
  78         kfree(ctrl);
  79 }
  80
  81 static const struct device_type serdev_ctrl_type = {
  82         .release        = serdev_ctrl_release,
  83 };
  84
  85 static int serdev_device_match(struct device *dev, struct device_driver *drv)
  86 {
  87         if (!is_serdev_device(dev))
  88                 return 0;
  89
  90         /* TODO: platform matching */
  91         if (acpi_driver_match_device(dev, drv))
  92                 return 1;
  93
  94         return of_driver_match_device(dev, drv);
  95 }
  96
  97 /**
  98  * serdev_device_add() - add a device previously constructed via serdev_device_alloc()
  99  * @serdev:     serdev_device to be added
 100  */
 101 int serdev_device_add(struct serdev_device *serdev)
 102 {
 103         struct serdev_controller *ctrl = serdev->ctrl;
 104         struct device *parent = serdev->dev.parent;
 105         int err;
 106
 107         dev_set_name(&serdev->dev, "%s-%d", dev_name(parent), serdev->nr);
 108
 109         /* Only a single slave device is currently supported. */
 110         if (ctrl->serdev) {
 111                 dev_err(&serdev->dev, "controller busy\n");
 112                 return -EBUSY;
 113         }
 114         ctrl->serdev = serdev;
 115
 116         err = device_add(&serdev->dev);
 117         if (err < 0) {
 118                 dev_err(&serdev->dev, "Can't add %s, status %pe\n",
 119                         dev_name(&serdev->dev), ERR_PTR(err));
 120                 goto err_clear_serdev;
 121         }
 122
 123         dev_dbg(&serdev->dev, "device %s registered\n", dev_name(&serdev->dev));
 124
 125         return 0;
 126
 127 err_clear_serdev:
 128         ctrl->serdev = NULL;
 129         return err;
 130 }
 131 EXPORT_SYMBOL_GPL(serdev_device_add);
 132
 133 /**
 134  * serdev_device_remove(): remove an serdev device
 135  * @serdev:     serdev_device to be removed
 136  */
 137 void serdev_device_remove(struct serdev_device *serdev)
 138 {
 139         struct serdev_controller *ctrl = serdev->ctrl;
 140
 141         device_unregister(&serdev->dev);
 142         ctrl->serdev = NULL;
 143 }
 144 EXPORT_SYMBOL_GPL(serdev_device_remove);
 145
 146 int serdev_device_open(struct serdev_device *serdev)
 147 {
 148         struct serdev_controller *ctrl = serdev->ctrl;
 149         int ret;
 150
 151         if (!ctrl || !ctrl->ops->open)
 152                 return -EINVAL;
 153
 154         ret = ctrl->ops->open(ctrl);
 155         if (ret)
 156                 return ret;
 157
 158         ret = pm_runtime_get_sync(&ctrl->dev);
 159         if (ret < 0) {
 160                 pm_runtime_put_noidle(&ctrl->dev);
 161                 goto err_close;
 162         }
 163
 164         return 0;
 165
 166 err_close:
 167         if (ctrl->ops->close)
 168                 ctrl->ops->close(ctrl);
 169
 170         return ret;
 171 }
 172 EXPORT_SYMBOL_GPL(serdev_device_open);
 173
 174 void serdev_device_close(struct serdev_device *serdev)
 175 {
 176         struct serdev_controller *ctrl = serdev->ctrl;
 177
 178         if (!ctrl || !ctrl->ops->close)
 179                 return;
 180
 181         pm_runtime_put(&ctrl->dev);
 182
 183         ctrl->ops->close(ctrl);
 184 }
 185 EXPORT_SYMBOL_GPL(serdev_device_close);
 186
 187 static void devm_serdev_device_release(struct device *dev, void *dr)
 188 {
 189         serdev_device_close(*(struct serdev_device **)dr);
 190 }
 191
 192 int devm_serdev_device_open(struct device *dev, struct serdev_device *serdev)
 193 {
 194         struct serdev_device **dr;
 195         int ret;
 196
 197         dr = devres_alloc(devm_serdev_device_release, sizeof(*dr), GFP_KERNEL);
 198         if (!dr)
 199                 return -ENOMEM;
 200
 201         ret = serdev_device_open(serdev);
 202         if (ret) {
 203                 devres_free(dr);
 204                 return ret;
 205         }
 206
 207         *dr = serdev;
 208         devres_add(dev, dr);
 209
 210         return 0;
 211 }
 212 EXPORT_SYMBOL_GPL(devm_serdev_device_open);
 213
 214 void serdev_device_write_wakeup(struct serdev_device *serdev)
 215 {
 216         complete(&serdev->write_comp);
 217 }
 218 EXPORT_SYMBOL_GPL(serdev_device_write_wakeup);
 219
 220 /**
 221  * serdev_device_write_buf() - write data asynchronously
 222  * @serdev:     serdev device
 223  * @buf:        data to be written
 224  * @count:      number of bytes to write
 225  *
 226  * Write data to the device asynchronously.
 227  *
 228  * Note that any accepted data has only been buffered by the controller; use
 229  * serdev_device_wait_until_sent() to make sure the controller write buffer
 230  * has actually been emptied.
 231  *
 232  * Return: The number of bytes written (less than count if not enough room in
 233  * the write buffer), or a negative errno on errors.
 234  */
 235 int serdev_device_write_buf(struct serdev_device *serdev,
 236                             const unsigned char *buf, size_t count)
 237 {
 238         struct serdev_controller *ctrl = serdev->ctrl;
 239
 240         if (!ctrl || !ctrl->ops->write_buf)
 241                 return -EINVAL;
 242
 243         return ctrl->ops->write_buf(ctrl, buf, count);
 244 }
 245 EXPORT_SYMBOL_GPL(serdev_device_write_buf);
 246
 247 /**
 248  * serdev_device_write() - write data synchronously
 249  * @serdev:     serdev device
 250  * @buf:        data to be written
 251  * @count:      number of bytes to write
 252  * @timeout:    timeout in jiffies, or 0 to wait indefinitely
 253  *
 254  * Write data to the device synchronously by repeatedly calling
 255  * serdev_device_write() until the controller has accepted all data (unless
 256  * interrupted by a timeout or a signal).
 257  *
 258  * Note that any accepted data has only been buffered by the controller; use
 259  * serdev_device_wait_until_sent() to make sure the controller write buffer
 260  * has actually been emptied.
 261  *
 262  * Note that this function depends on serdev_device_write_wakeup() being
 263  * called in the serdev driver write_wakeup() callback.
 264  *
 265  * Return: The number of bytes written (less than count if interrupted),
 266  * -ETIMEDOUT or -ERESTARTSYS if interrupted before any bytes were written, or
 267  * a negative errno on errors.
 268  */
 269 int serdev_device_write(struct serdev_device *serdev,
 270                         const unsigned char *buf, size_t count,
 271                         long timeout)
 272 {
 273         struct serdev_controller *ctrl = serdev->ctrl;
 274         int written = 0;
 275         int ret;
 276
 277         if (!ctrl || !ctrl->ops->write_buf || !serdev->ops->write_wakeup)
 278                 return -EINVAL;
 279
 280         if (timeout == 0)
 281                 timeout = MAX_SCHEDULE_TIMEOUT;
 282
 283         mutex_lock(&serdev->write_lock);
 284         do {
 285                 reinit_completion(&serdev->write_comp);
 286
 287                 ret = ctrl->ops->write_buf(ctrl, buf, count);
 288                 if (ret < 0)
 289                         break;
 290
 291                 written += ret;
 292                 buf += ret;
 293                 count -= ret;
 294
 295                 if (count == 0)
 296                         break;
 297
 298                 timeout = wait_for_completion_interruptible_timeout(&serdev->write_comp,
 299                                                                     timeout);
 300         } while (timeout > 0);
 301         mutex_unlock(&serdev->write_lock);
 302
 303         if (ret < 0)
 304                 return ret;
 305
 306         if (timeout <= 0 && written == 0) {
 307                 if (timeout == -ERESTARTSYS)
 308                         return -ERESTARTSYS;
 309                 else
 310                         return -ETIMEDOUT;
 311         }
 312
 313         return written;
 314 }
 315 EXPORT_SYMBOL_GPL(serdev_device_write);
 316
 317 void serdev_device_write_flush(struct serdev_device *serdev)
 318 {
 319         struct serdev_controller *ctrl = serdev->ctrl;
 320
 321         if (!ctrl || !ctrl->ops->write_flush)
 322                 return;
 323
 324         ctrl->ops->write_flush(ctrl);
 325 }
 326 EXPORT_SYMBOL_GPL(serdev_device_write_flush);
 327
 328 int serdev_device_write_room(struct serdev_device *serdev)
 329 {
 330         struct serdev_controller *ctrl = serdev->ctrl;
 331
 332         if (!ctrl || !ctrl->ops->write_room)
 333                 return 0;
 334
 335         return serdev->ctrl->ops->write_room(ctrl);
 336 }
 337 EXPORT_SYMBOL_GPL(serdev_device_write_room);
 338
 339 unsigned int serdev_device_set_baudrate(struct serdev_device *serdev, unsigned int speed)
 340 {
 341         struct serdev_controller *ctrl = serdev->ctrl;
 342
 343         if (!ctrl || !ctrl->ops->set_baudrate)
 344                 return 0;
 345
 346         return ctrl->ops->set_baudrate(ctrl, speed);
 347
 348 }
 349 EXPORT_SYMBOL_GPL(serdev_device_set_baudrate);
 350
 351 void serdev_device_set_flow_control(struct serdev_device *serdev, bool enable)
 352 {
 353         struct serdev_controller *ctrl = serdev->ctrl;
 354
 355         if (!ctrl || !ctrl->ops->set_flow_control)
 356                 return;
 357
 358         ctrl->ops->set_flow_control(ctrl, enable);
 359 }
 360 EXPORT_SYMBOL_GPL(serdev_device_set_flow_control);
 361
 362 int serdev_device_set_parity(struct serdev_device *serdev,
 363                              enum serdev_parity parity)
 364 {
 365         struct serdev_controller *ctrl = serdev->ctrl;
 366
 367         if (!ctrl || !ctrl->ops->set_parity)
 368                 return -ENOTSUPP;
 369
 370         return ctrl->ops->set_parity(ctrl, parity);
 371 }
 372 EXPORT_SYMBOL_GPL(serdev_device_set_parity);
 373
 374 void serdev_device_wait_until_sent(struct serdev_device *serdev, long timeout)
 375 {
 376         struct serdev_controller *ctrl = serdev->ctrl;
 377
 378         if (!ctrl || !ctrl->ops->wait_until_sent)
 379                 return;
 380
 381         ctrl->ops->wait_until_sent(ctrl, timeout);
 382 }
 383 EXPORT_SYMBOL_GPL(serdev_device_wait_until_sent);
 384
 385 int serdev_device_get_tiocm(struct serdev_device *serdev)
 386 {
 387         struct serdev_controller *ctrl = serdev->ctrl;
 388
 389         if (!ctrl || !ctrl->ops->get_tiocm)
 390                 return -ENOTSUPP;
 391
 392         return ctrl->ops->get_tiocm(ctrl);
 393 }
 394 EXPORT_SYMBOL_GPL(serdev_device_get_tiocm);
 395
 396 int serdev_device_set_tiocm(struct serdev_device *serdev, int set, int clear)
 397 {
 398         struct serdev_controller *ctrl = serdev->ctrl;
 399
 400         if (!ctrl || !ctrl->ops->set_tiocm)
 401                 return -ENOTSUPP;
 402
 403         return ctrl->ops->set_tiocm(ctrl, set, clear);
 404 }
 405 EXPORT_SYMBOL_GPL(serdev_device_set_tiocm);
 406
 407 static int serdev_drv_probe(struct device *dev)
 408 {
 409         const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
 410         int ret;
 411
 412         ret = dev_pm_domain_attach(dev, true);
 413         if (ret)
 414                 return ret;
 415
 416         ret = sdrv->probe(to_serdev_device(dev));
 417         if (ret)
 418                 dev_pm_domain_detach(dev, true);
 419
 420         return ret;
 421 }
 422
 423 static int serdev_drv_remove(struct device *dev)
 424 {
 425         const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
 426         if (sdrv->remove)
 427                 sdrv->remove(to_serdev_device(dev));
 428
 429         dev_pm_domain_detach(dev, true);
 430
 431         return 0;
 432 }
 433
 434 static struct bus_type serdev_bus_type = {
 435         .name           = "serial",
 436         .match          = serdev_device_match,
 437         .probe          = serdev_drv_probe,
 438         .remove         = serdev_drv_remove,
 439 };
 440
 441 /**
 442  * serdev_device_alloc() - Allocate a new serdev device
 443  * @ctrl:       associated controller
 444  *
 445  * Caller is responsible for either calling serdev_device_add() to add the
 446  * newly allocated controller, or calling serdev_device_put() to discard it.
 447  */
 448 struct serdev_device *serdev_device_alloc(struct serdev_controller *ctrl)
 449 {
 450         struct serdev_device *serdev;
 451
 452         serdev = kzalloc(sizeof(*serdev), GFP_KERNEL);
 453         if (!serdev)
 454                 return NULL;
 455
 456         serdev->ctrl = ctrl;
 457         device_initialize(&serdev->dev);
 458         serdev->dev.parent = &ctrl->dev;
 459         serdev->dev.bus = &serdev_bus_type;
 460         serdev->dev.type = &serdev_device_type;
 461         init_completion(&serdev->write_comp);
 462         mutex_init(&serdev->write_lock);
 463         return serdev;
 464 }
 465 EXPORT_SYMBOL_GPL(serdev_device_alloc);
 466
 467 /**
 468  * serdev_controller_alloc() - Allocate a new serdev controller
 469  * @parent:     parent device
 470  * @size:       size of private data
 471  *
 472  * Caller is responsible for either calling serdev_controller_add() to add the
 473  * newly allocated controller, or calling serdev_controller_put() to discard it.
 474  * The allocated private data region may be accessed via
 475  * serdev_controller_get_drvdata()
 476  */
 477 struct serdev_controller *serdev_controller_alloc(struct device *parent,
 478                                               size_t size)
 479 {
 480         struct serdev_controller *ctrl;
 481         int id;
 482
 483         if (WARN_ON(!parent))
 484                 return NULL;
 485
 486         ctrl = kzalloc(sizeof(*ctrl) + size, GFP_KERNEL);
 487         if (!ctrl)
 488                 return NULL;
 489
 490         id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
 491         if (id < 0) {
 492                 dev_err(parent,
 493                         "unable to allocate serdev controller identifier.\n");
 494                 goto err_free;
 495         }
 496
 497         ctrl->nr = id;
 498
 499         device_initialize(&ctrl->dev);
 500         ctrl->dev.type = &serdev_ctrl_type;
 501         ctrl->dev.bus = &serdev_bus_type;
 502         ctrl->dev.parent = parent;
 503         ctrl->dev.of_node = parent->of_node;
 504         serdev_controller_set_drvdata(ctrl, &ctrl[1]);
 505
 506         dev_set_name(&ctrl->dev, "serial%d", id);
 507
 508         pm_runtime_no_callbacks(&ctrl->dev);
 509         pm_suspend_ignore_children(&ctrl->dev, true);
 510
 511         dev_dbg(&ctrl->dev, "allocated controller 0x%p id %d\n", ctrl, id);
 512         return ctrl;
 513
 514 err_free:
 515         kfree(ctrl);
 516
 517         return NULL;
 518 }
 519 EXPORT_SYMBOL_GPL(serdev_controller_alloc);
 520
 521 static int of_serdev_register_devices(struct serdev_controller *ctrl)
 522 {
 523         struct device_node *node;
 524         struct serdev_device *serdev = NULL;
 525         int err;
 526         bool found = false;
 527
 528         for_each_available_child_of_node(ctrl->dev.of_node, node) {
 529                 if (!of_get_property(node, "compatible", NULL))
 530                         continue;
 531
 532                 dev_dbg(&ctrl->dev, "adding child %pOF\n", node);
 533
 534                 serdev = serdev_device_alloc(ctrl);
 535                 if (!serdev)
 536                         continue;
 537
 538                 serdev->dev.of_node = node;
 539
 540                 err = serdev_device_add(serdev);
 541                 if (err) {
 542                         dev_err(&serdev->dev,
 543                                 "failure adding device. status %pe\n",
 544                                 ERR_PTR(err));
 545                         serdev_device_put(serdev);
 546                 } else
 547                         found = true;
 548         }
 549         if (!found)
 550                 return -ENODEV;
 551
 552         return 0;
 553 }
 554
 555 #ifdef CONFIG_ACPI
 556
 557 #define SERDEV_ACPI_MAX_SCAN_DEPTH 32
 558
 559 struct acpi_serdev_lookup {
 560         acpi_handle device_handle;
 561         acpi_handle controller_handle;
 562         int n;
 563         int index;
 564 };
 565
 566 static int acpi_serdev_parse_resource(struct acpi_resource *ares, void *data)
 567 {
 568         struct acpi_serdev_lookup *lookup = data;
 569         struct acpi_resource_uart_serialbus *sb;
 570         acpi_status status;
 571
 572         if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
 573                 return 1;
 574
 575         if (ares->data.common_serial_bus.type != ACPI_RESOURCE_SERIAL_TYPE_UART)
 576                 return 1;
 577
 578         if (lookup->index != -1 && lookup->n++ != lookup->index)
 579                 return 1;
 580
 581         sb = &ares->data.uart_serial_bus;
 582
 583         status = acpi_get_handle(lookup->device_handle,
 584                                  sb->resource_source.string_ptr,
 585                                  &lookup->controller_handle);
 586         if (ACPI_FAILURE(status))
 587                 return 1;
 588
 589         /*
 590          * NOTE: Ideally, we would also want to retreive other properties here,
 591          * once setting them before opening the device is supported by serdev.
 592          */
 593
 594         return 1;
 595 }
 596
 597 static int acpi_serdev_do_lookup(struct acpi_device *adev,
 598                                  struct acpi_serdev_lookup *lookup)
 599 {
 600         struct list_head resource_list;
 601         int ret;
 602
 603         lookup->device_handle = acpi_device_handle(adev);
 604         lookup->controller_handle = NULL;
 605         lookup->n = 0;
 606
 607         INIT_LIST_HEAD(&resource_list);
 608         ret = acpi_dev_get_resources(adev, &resource_list,
 609                                      acpi_serdev_parse_resource, lookup);
 610         acpi_dev_free_resource_list(&resource_list);
 611
 612         if (ret < 0)
 613                 return -EINVAL;
 614
 615         return 0;
 616 }
 617
 618 static int acpi_serdev_check_resources(struct serdev_controller *ctrl,
 619                                        struct acpi_device *adev)
 620 {
 621         struct acpi_serdev_lookup lookup;
 622         int ret;
 623
 624         if (acpi_bus_get_status(adev) || !adev->status.present)
 625                 return -EINVAL;
 626
 627         /* Look for UARTSerialBusV2 resource */
 628         lookup.index = -1;      // we only care for the last device
 629
 630         ret = acpi_serdev_do_lookup(adev, &lookup);
 631         if (ret)
 632                 return ret;
 633
 634         /* Make sure controller and ResourceSource handle match */
 635         if (ACPI_HANDLE(ctrl->dev.parent) != lookup.controller_handle)
 636                 return -ENODEV;
 637
 638         return 0;
 639 }
 640
 641 static acpi_status acpi_serdev_register_device(struct serdev_controller *ctrl,
 642                                                struct acpi_device *adev)
 643 {
 644         struct serdev_device *serdev;
 645         int err;
 646
 647         serdev = serdev_device_alloc(ctrl);
 648         if (!serdev) {
 649                 dev_err(&ctrl->dev, "failed to allocate serdev device for %s\n",
 650                         dev_name(&adev->dev));
 651                 return AE_NO_MEMORY;
 652         }
 653
 654         ACPI_COMPANION_SET(&serdev->dev, adev);
 655         acpi_device_set_enumerated(adev);
 656
 657         err = serdev_device_add(serdev);
 658         if (err) {
 659                 dev_err(&serdev->dev,
 660                         "failure adding ACPI serdev device. status %pe\n",
 661                         ERR_PTR(err));
 662                 serdev_device_put(serdev);
 663         }
 664
 665         return AE_OK;
 666 }
 667
 668 static const struct acpi_device_id serdev_acpi_devices_blacklist[] = {
 669         { "INT3511", 0 },
 670         { "INT3512", 0 },
 671         { },
 672 };
 673
 674 static acpi_status acpi_serdev_add_device(acpi_handle handle, u32 level,
 675                                           void *data, void **return_value)
 676 {
 677         struct serdev_controller *ctrl = data;
 678         struct acpi_device *adev;
 679
 680         if (acpi_bus_get_device(handle, &adev))
 681                 return AE_OK;
 682
 683         if (acpi_device_enumerated(adev))
 684                 return AE_OK;
 685
 686         /* Skip if black listed */
 687         if (!acpi_match_device_ids(adev, serdev_acpi_devices_blacklist))
 688                 return AE_OK;
 689
 690         if (acpi_serdev_check_resources(ctrl, adev))
 691                 return AE_OK;
 692
 693         return acpi_serdev_register_device(ctrl, adev);
 694 }
 695
 696
 697 static int acpi_serdev_register_devices(struct serdev_controller *ctrl)
 698 {
 699         acpi_status status;
 700
 701         if (!has_acpi_companion(ctrl->dev.parent))
 702                 return -ENODEV;
 703
 704         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 705                                      SERDEV_ACPI_MAX_SCAN_DEPTH,
 706                                      acpi_serdev_add_device, NULL, ctrl, NULL);
 707         if (ACPI_FAILURE(status))
 708                 dev_warn(&ctrl->dev, "failed to enumerate serdev slaves\n");
 709
 710         if (!ctrl->serdev)
 711                 return -ENODEV;
 712
 713         return 0;
 714 }
 715 #else
 716 static inline int acpi_serdev_register_devices(struct serdev_controller *ctrl)
 717 {
 718         return -ENODEV;
 719 }
 720 #endif /* CONFIG_ACPI */
 721
 722 /**
 723  * serdev_controller_add() - Add an serdev controller
 724  * @ctrl:       controller to be registered.
 725  *
 726  * Register a controller previously allocated via serdev_controller_alloc() with
 727  * the serdev core.
 728  */
 729 int serdev_controller_add(struct serdev_controller *ctrl)
 730 {
 731         int ret_of, ret_acpi, ret;
 732
 733         /* Can't register until after driver model init */
 734         if (WARN_ON(!is_registered))
 735                 return -EAGAIN;
 736
 737         ret = device_add(&ctrl->dev);
 738         if (ret)
 739                 return ret;
 740
 741         pm_runtime_enable(&ctrl->dev);
 742
 743         ret_of = of_serdev_register_devices(ctrl);
 744         ret_acpi = acpi_serdev_register_devices(ctrl);
 745         if (ret_of && ret_acpi) {
 746                 dev_dbg(&ctrl->dev, "no devices registered: of:%pe acpi:%pe\n",
 747                         ERR_PTR(ret_of), ERR_PTR(ret_acpi));
 748                 ret = -ENODEV;
 749                 goto err_rpm_disable;
 750         }
 751
 752         dev_dbg(&ctrl->dev, "serdev%d registered: dev:%p\n",
 753                 ctrl->nr, &ctrl->dev);
 754         return 0;
 755
 756 err_rpm_disable:
 757         pm_runtime_disable(&ctrl->dev);
 758         device_del(&ctrl->dev);
 759         return ret;
 760 };
 761 EXPORT_SYMBOL_GPL(serdev_controller_add);
 762
 763 /* Remove a device associated with a controller */
 764 static int serdev_remove_device(struct device *dev, void *data)
 765 {
 766         struct serdev_device *serdev = to_serdev_device(dev);
 767         if (dev->type == &serdev_device_type)
 768                 serdev_device_remove(serdev);
 769         return 0;
 770 }
 771
 772 /**
 773  * serdev_controller_remove(): remove an serdev controller
 774  * @ctrl:       controller to remove
 775  *
 776  * Remove a serdev controller.  Caller is responsible for calling
 777  * serdev_controller_put() to discard the allocated controller.
 778  */
 779 void serdev_controller_remove(struct serdev_controller *ctrl)
 780 {
 781         int dummy;
 782
 783         if (!ctrl)
 784                 return;
 785
 786         dummy = device_for_each_child(&ctrl->dev, NULL,
 787                                       serdev_remove_device);
 788         pm_runtime_disable(&ctrl->dev);
 789         device_del(&ctrl->dev);
 790 }
 791 EXPORT_SYMBOL_GPL(serdev_controller_remove);
 792
 793 /**
 794  * serdev_driver_register() - Register client driver with serdev core
 795  * @sdrv:       client driver to be associated with client-device.
 796  *
 797  * This API will register the client driver with the serdev framework.
 798  * It is typically called from the driver's module-init function.
 799  */
 800 int __serdev_device_driver_register(struct serdev_device_driver *sdrv, struct module *owner)
 801 {
 802         sdrv->driver.bus = &serdev_bus_type;
 803         sdrv->driver.owner = owner;
 804
 805         /* force drivers to async probe so I/O is possible in probe */
 806         sdrv->driver.probe_type = PROBE_PREFER_ASYNCHRONOUS;
 807
 808         return driver_register(&sdrv->driver);
 809 }
 810 EXPORT_SYMBOL_GPL(__serdev_device_driver_register);
 811
 812 static void __exit serdev_exit(void)
 813 {
 814         bus_unregister(&serdev_bus_type);
 815         ida_destroy(&ctrl_ida);
 816 }
 817 module_exit(serdev_exit);
 818
 819 static int __init serdev_init(void)
 820 {
 821         int ret;
 822
 823         ret = bus_register(&serdev_bus_type);
 824         if (ret)
 825                 return ret;
 826
 827         is_registered = true;
 828         return 0;
 829 }
 830 /* Must be before serial drivers register */
 831 postcore_initcall(serdev_init);
 832
 833 MODULE_AUTHOR("Rob Herring <robh@kernel.org>");
 834 MODULE_LICENSE("GPL v2");
 835 MODULE_DESCRIPTION("Serial attached device bus");