linux/drivers/tty/serdev/core.c
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   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#include <linux/platform_data/x86/apple.h>
  22
  23static bool is_registered;
  24static DEFINE_IDA(ctrl_ida);
  25
  26static ssize_t modalias_show(struct device *dev,
  27                             struct device_attribute *attr, char *buf)
  28{
  29        int len;
  30
  31        len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  32        if (len != -ENODEV)
  33                return len;
  34
  35        return of_device_modalias(dev, buf, PAGE_SIZE);
  36}
  37static DEVICE_ATTR_RO(modalias);
  38
  39static struct attribute *serdev_device_attrs[] = {
  40        &dev_attr_modalias.attr,
  41        NULL,
  42};
  43ATTRIBUTE_GROUPS(serdev_device);
  44
  45static int serdev_device_uevent(struct device *dev, struct kobj_uevent_env *env)
  46{
  47        int rc;
  48
  49        /* TODO: platform modalias */
  50
  51        rc = acpi_device_uevent_modalias(dev, env);
  52        if (rc != -ENODEV)
  53                return rc;
  54
  55        return of_device_uevent_modalias(dev, env);
  56}
  57
  58static void serdev_device_release(struct device *dev)
  59{
  60        struct serdev_device *serdev = to_serdev_device(dev);
  61        kfree(serdev);
  62}
  63
  64static const struct device_type serdev_device_type = {
  65        .groups         = serdev_device_groups,
  66        .uevent         = serdev_device_uevent,
  67        .release        = serdev_device_release,
  68};
  69
  70static bool is_serdev_device(const struct device *dev)
  71{
  72        return dev->type == &serdev_device_type;
  73}
  74
  75static void serdev_ctrl_release(struct device *dev)
  76{
  77        struct serdev_controller *ctrl = to_serdev_controller(dev);
  78        ida_simple_remove(&ctrl_ida, ctrl->nr);
  79        kfree(ctrl);
  80}
  81
  82static const struct device_type serdev_ctrl_type = {
  83        .release        = serdev_ctrl_release,
  84};
  85
  86static int serdev_device_match(struct device *dev, struct device_driver *drv)
  87{
  88        if (!is_serdev_device(dev))
  89                return 0;
  90
  91        /* TODO: platform matching */
  92        if (acpi_driver_match_device(dev, drv))
  93                return 1;
  94
  95        return of_driver_match_device(dev, drv);
  96}
  97
  98/**
  99 * serdev_device_add() - add a device previously constructed via serdev_device_alloc()
 100 * @serdev:     serdev_device to be added
 101 */
 102int serdev_device_add(struct serdev_device *serdev)
 103{
 104        struct serdev_controller *ctrl = serdev->ctrl;
 105        struct device *parent = serdev->dev.parent;
 106        int err;
 107
 108        dev_set_name(&serdev->dev, "%s-%d", dev_name(parent), serdev->nr);
 109
 110        /* Only a single slave device is currently supported. */
 111        if (ctrl->serdev) {
 112                dev_err(&serdev->dev, "controller busy\n");
 113                return -EBUSY;
 114        }
 115        ctrl->serdev = serdev;
 116
 117        err = device_add(&serdev->dev);
 118        if (err < 0) {
 119                dev_err(&serdev->dev, "Can't add %s, status %pe\n",
 120                        dev_name(&serdev->dev), ERR_PTR(err));
 121                goto err_clear_serdev;
 122        }
 123
 124        dev_dbg(&serdev->dev, "device %s registered\n", dev_name(&serdev->dev));
 125
 126        return 0;
 127
 128err_clear_serdev:
 129        ctrl->serdev = NULL;
 130        return err;
 131}
 132EXPORT_SYMBOL_GPL(serdev_device_add);
 133
 134/**
 135 * serdev_device_remove(): remove an serdev device
 136 * @serdev:     serdev_device to be removed
 137 */
 138void serdev_device_remove(struct serdev_device *serdev)
 139{
 140        struct serdev_controller *ctrl = serdev->ctrl;
 141
 142        device_unregister(&serdev->dev);
 143        ctrl->serdev = NULL;
 144}
 145EXPORT_SYMBOL_GPL(serdev_device_remove);
 146
 147int serdev_device_open(struct serdev_device *serdev)
 148{
 149        struct serdev_controller *ctrl = serdev->ctrl;
 150        int ret;
 151
 152        if (!ctrl || !ctrl->ops->open)
 153                return -EINVAL;
 154
 155        ret = ctrl->ops->open(ctrl);
 156        if (ret)
 157                return ret;
 158
 159        ret = pm_runtime_get_sync(&ctrl->dev);
 160        if (ret < 0) {
 161                pm_runtime_put_noidle(&ctrl->dev);
 162                goto err_close;
 163        }
 164
 165        return 0;
 166
 167err_close:
 168        if (ctrl->ops->close)
 169                ctrl->ops->close(ctrl);
 170
 171        return ret;
 172}
 173EXPORT_SYMBOL_GPL(serdev_device_open);
 174
 175void serdev_device_close(struct serdev_device *serdev)
 176{
 177        struct serdev_controller *ctrl = serdev->ctrl;
 178
 179        if (!ctrl || !ctrl->ops->close)
 180                return;
 181
 182        pm_runtime_put(&ctrl->dev);
 183
 184        ctrl->ops->close(ctrl);
 185}
 186EXPORT_SYMBOL_GPL(serdev_device_close);
 187
 188static void devm_serdev_device_release(struct device *dev, void *dr)
 189{
 190        serdev_device_close(*(struct serdev_device **)dr);
 191}
 192
 193int devm_serdev_device_open(struct device *dev, struct serdev_device *serdev)
 194{
 195        struct serdev_device **dr;
 196        int ret;
 197
 198        dr = devres_alloc(devm_serdev_device_release, sizeof(*dr), GFP_KERNEL);
 199        if (!dr)
 200                return -ENOMEM;
 201
 202        ret = serdev_device_open(serdev);
 203        if (ret) {
 204                devres_free(dr);
 205                return ret;
 206        }
 207
 208        *dr = serdev;
 209        devres_add(dev, dr);
 210
 211        return 0;
 212}
 213EXPORT_SYMBOL_GPL(devm_serdev_device_open);
 214
 215void serdev_device_write_wakeup(struct serdev_device *serdev)
 216{
 217        complete(&serdev->write_comp);
 218}
 219EXPORT_SYMBOL_GPL(serdev_device_write_wakeup);
 220
 221/**
 222 * serdev_device_write_buf() - write data asynchronously
 223 * @serdev:     serdev device
 224 * @buf:        data to be written
 225 * @count:      number of bytes to write
 226 *
 227 * Write data to the device asynchronously.
 228 *
 229 * Note that any accepted data has only been buffered by the controller; use
 230 * serdev_device_wait_until_sent() to make sure the controller write buffer
 231 * has actually been emptied.
 232 *
 233 * Return: The number of bytes written (less than count if not enough room in
 234 * the write buffer), or a negative errno on errors.
 235 */
 236int serdev_device_write_buf(struct serdev_device *serdev,
 237                            const unsigned char *buf, size_t count)
 238{
 239        struct serdev_controller *ctrl = serdev->ctrl;
 240
 241        if (!ctrl || !ctrl->ops->write_buf)
 242                return -EINVAL;
 243
 244        return ctrl->ops->write_buf(ctrl, buf, count);
 245}
 246EXPORT_SYMBOL_GPL(serdev_device_write_buf);
 247
 248/**
 249 * serdev_device_write() - write data synchronously
 250 * @serdev:     serdev device
 251 * @buf:        data to be written
 252 * @count:      number of bytes to write
 253 * @timeout:    timeout in jiffies, or 0 to wait indefinitely
 254 *
 255 * Write data to the device synchronously by repeatedly calling
 256 * serdev_device_write() until the controller has accepted all data (unless
 257 * interrupted by a timeout or a signal).
 258 *
 259 * Note that any accepted data has only been buffered by the controller; use
 260 * serdev_device_wait_until_sent() to make sure the controller write buffer
 261 * has actually been emptied.
 262 *
 263 * Note that this function depends on serdev_device_write_wakeup() being
 264 * called in the serdev driver write_wakeup() callback.
 265 *
 266 * Return: The number of bytes written (less than count if interrupted),
 267 * -ETIMEDOUT or -ERESTARTSYS if interrupted before any bytes were written, or
 268 * a negative errno on errors.
 269 */
 270int serdev_device_write(struct serdev_device *serdev,
 271                        const unsigned char *buf, size_t count,
 272                        long timeout)
 273{
 274        struct serdev_controller *ctrl = serdev->ctrl;
 275        int written = 0;
 276        int ret;
 277
 278        if (!ctrl || !ctrl->ops->write_buf || !serdev->ops->write_wakeup)
 279                return -EINVAL;
 280
 281        if (timeout == 0)
 282                timeout = MAX_SCHEDULE_TIMEOUT;
 283
 284        mutex_lock(&serdev->write_lock);
 285        do {
 286                reinit_completion(&serdev->write_comp);
 287
 288                ret = ctrl->ops->write_buf(ctrl, buf, count);
 289                if (ret < 0)
 290                        break;
 291
 292                written += ret;
 293                buf += ret;
 294                count -= ret;
 295
 296                if (count == 0)
 297                        break;
 298
 299                timeout = wait_for_completion_interruptible_timeout(&serdev->write_comp,
 300                                                                    timeout);
 301        } while (timeout > 0);
 302        mutex_unlock(&serdev->write_lock);
 303
 304        if (ret < 0)
 305                return ret;
 306
 307        if (timeout <= 0 && written == 0) {
 308                if (timeout == -ERESTARTSYS)
 309                        return -ERESTARTSYS;
 310                else
 311                        return -ETIMEDOUT;
 312        }
 313
 314        return written;
 315}
 316EXPORT_SYMBOL_GPL(serdev_device_write);
 317
 318void serdev_device_write_flush(struct serdev_device *serdev)
 319{
 320        struct serdev_controller *ctrl = serdev->ctrl;
 321
 322        if (!ctrl || !ctrl->ops->write_flush)
 323                return;
 324
 325        ctrl->ops->write_flush(ctrl);
 326}
 327EXPORT_SYMBOL_GPL(serdev_device_write_flush);
 328
 329int serdev_device_write_room(struct serdev_device *serdev)
 330{
 331        struct serdev_controller *ctrl = serdev->ctrl;
 332
 333        if (!ctrl || !ctrl->ops->write_room)
 334                return 0;
 335
 336        return serdev->ctrl->ops->write_room(ctrl);
 337}
 338EXPORT_SYMBOL_GPL(serdev_device_write_room);
 339
 340unsigned int serdev_device_set_baudrate(struct serdev_device *serdev, unsigned int speed)
 341{
 342        struct serdev_controller *ctrl = serdev->ctrl;
 343
 344        if (!ctrl || !ctrl->ops->set_baudrate)
 345                return 0;
 346
 347        return ctrl->ops->set_baudrate(ctrl, speed);
 348
 349}
 350EXPORT_SYMBOL_GPL(serdev_device_set_baudrate);
 351
 352void serdev_device_set_flow_control(struct serdev_device *serdev, bool enable)
 353{
 354        struct serdev_controller *ctrl = serdev->ctrl;
 355
 356        if (!ctrl || !ctrl->ops->set_flow_control)
 357                return;
 358
 359        ctrl->ops->set_flow_control(ctrl, enable);
 360}
 361EXPORT_SYMBOL_GPL(serdev_device_set_flow_control);
 362
 363int serdev_device_set_parity(struct serdev_device *serdev,
 364                             enum serdev_parity parity)
 365{
 366        struct serdev_controller *ctrl = serdev->ctrl;
 367
 368        if (!ctrl || !ctrl->ops->set_parity)
 369                return -ENOTSUPP;
 370
 371        return ctrl->ops->set_parity(ctrl, parity);
 372}
 373EXPORT_SYMBOL_GPL(serdev_device_set_parity);
 374
 375void serdev_device_wait_until_sent(struct serdev_device *serdev, long timeout)
 376{
 377        struct serdev_controller *ctrl = serdev->ctrl;
 378
 379        if (!ctrl || !ctrl->ops->wait_until_sent)
 380                return;
 381
 382        ctrl->ops->wait_until_sent(ctrl, timeout);
 383}
 384EXPORT_SYMBOL_GPL(serdev_device_wait_until_sent);
 385
 386int serdev_device_get_tiocm(struct serdev_device *serdev)
 387{
 388        struct serdev_controller *ctrl = serdev->ctrl;
 389
 390        if (!ctrl || !ctrl->ops->get_tiocm)
 391                return -ENOTSUPP;
 392
 393        return ctrl->ops->get_tiocm(ctrl);
 394}
 395EXPORT_SYMBOL_GPL(serdev_device_get_tiocm);
 396
 397int serdev_device_set_tiocm(struct serdev_device *serdev, int set, int clear)
 398{
 399        struct serdev_controller *ctrl = serdev->ctrl;
 400
 401        if (!ctrl || !ctrl->ops->set_tiocm)
 402                return -ENOTSUPP;
 403
 404        return ctrl->ops->set_tiocm(ctrl, set, clear);
 405}
 406EXPORT_SYMBOL_GPL(serdev_device_set_tiocm);
 407
 408static int serdev_drv_probe(struct device *dev)
 409{
 410        const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
 411        int ret;
 412
 413        ret = dev_pm_domain_attach(dev, true);
 414        if (ret)
 415                return ret;
 416
 417        ret = sdrv->probe(to_serdev_device(dev));
 418        if (ret)
 419                dev_pm_domain_detach(dev, true);
 420
 421        return ret;
 422}
 423
 424static int serdev_drv_remove(struct device *dev)
 425{
 426        const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
 427        if (sdrv->remove)
 428                sdrv->remove(to_serdev_device(dev));
 429
 430        dev_pm_domain_detach(dev, true);
 431
 432        return 0;
 433}
 434
 435static struct bus_type serdev_bus_type = {
 436        .name           = "serial",
 437        .match          = serdev_device_match,
 438        .probe          = serdev_drv_probe,
 439        .remove         = serdev_drv_remove,
 440};
 441
 442/**
 443 * serdev_device_alloc() - Allocate a new serdev device
 444 * @ctrl:       associated controller
 445 *
 446 * Caller is responsible for either calling serdev_device_add() to add the
 447 * newly allocated controller, or calling serdev_device_put() to discard it.
 448 */
 449struct serdev_device *serdev_device_alloc(struct serdev_controller *ctrl)
 450{
 451        struct serdev_device *serdev;
 452
 453        serdev = kzalloc(sizeof(*serdev), GFP_KERNEL);
 454        if (!serdev)
 455                return NULL;
 456
 457        serdev->ctrl = ctrl;
 458        device_initialize(&serdev->dev);
 459        serdev->dev.parent = &ctrl->dev;
 460        serdev->dev.bus = &serdev_bus_type;
 461        serdev->dev.type = &serdev_device_type;
 462        init_completion(&serdev->write_comp);
 463        mutex_init(&serdev->write_lock);
 464        return serdev;
 465}
 466EXPORT_SYMBOL_GPL(serdev_device_alloc);
 467
 468/**
 469 * serdev_controller_alloc() - Allocate a new serdev controller
 470 * @parent:     parent device
 471 * @size:       size of private data
 472 *
 473 * Caller is responsible for either calling serdev_controller_add() to add the
 474 * newly allocated controller, or calling serdev_controller_put() to discard it.
 475 * The allocated private data region may be accessed via
 476 * serdev_controller_get_drvdata()
 477 */
 478struct serdev_controller *serdev_controller_alloc(struct device *parent,
 479                                              size_t size)
 480{
 481        struct serdev_controller *ctrl;
 482        int id;
 483
 484        if (WARN_ON(!parent))
 485                return NULL;
 486
 487        ctrl = kzalloc(sizeof(*ctrl) + size, GFP_KERNEL);
 488        if (!ctrl)
 489                return NULL;
 490
 491        id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
 492        if (id < 0) {
 493                dev_err(parent,
 494                        "unable to allocate serdev controller identifier.\n");
 495                goto err_free;
 496        }
 497
 498        ctrl->nr = id;
 499
 500        device_initialize(&ctrl->dev);
 501        ctrl->dev.type = &serdev_ctrl_type;
 502        ctrl->dev.bus = &serdev_bus_type;
 503        ctrl->dev.parent = parent;
 504        ctrl->dev.of_node = parent->of_node;
 505        serdev_controller_set_drvdata(ctrl, &ctrl[1]);
 506
 507        dev_set_name(&ctrl->dev, "serial%d", id);
 508
 509        pm_runtime_no_callbacks(&ctrl->dev);
 510        pm_suspend_ignore_children(&ctrl->dev, true);
 511
 512        dev_dbg(&ctrl->dev, "allocated controller 0x%p id %d\n", ctrl, id);
 513        return ctrl;
 514
 515err_free:
 516        kfree(ctrl);
 517
 518        return NULL;
 519}
 520EXPORT_SYMBOL_GPL(serdev_controller_alloc);
 521
 522static int of_serdev_register_devices(struct serdev_controller *ctrl)
 523{
 524        struct device_node *node;
 525        struct serdev_device *serdev = NULL;
 526        int err;
 527        bool found = false;
 528
 529        for_each_available_child_of_node(ctrl->dev.of_node, node) {
 530                if (!of_get_property(node, "compatible", NULL))
 531                        continue;
 532
 533                dev_dbg(&ctrl->dev, "adding child %pOF\n", node);
 534
 535                serdev = serdev_device_alloc(ctrl);
 536                if (!serdev)
 537                        continue;
 538
 539                serdev->dev.of_node = node;
 540
 541                err = serdev_device_add(serdev);
 542                if (err) {
 543                        dev_err(&serdev->dev,
 544                                "failure adding device. status %pe\n",
 545                                ERR_PTR(err));
 546                        serdev_device_put(serdev);
 547                } else
 548                        found = true;
 549        }
 550        if (!found)
 551                return -ENODEV;
 552
 553        return 0;
 554}
 555
 556#ifdef CONFIG_ACPI
 557
 558#define SERDEV_ACPI_MAX_SCAN_DEPTH 32
 559
 560struct acpi_serdev_lookup {
 561        acpi_handle device_handle;
 562        acpi_handle controller_handle;
 563        int n;
 564        int index;
 565};
 566
 567static int acpi_serdev_parse_resource(struct acpi_resource *ares, void *data)
 568{
 569        struct acpi_serdev_lookup *lookup = data;
 570        struct acpi_resource_uart_serialbus *sb;
 571        acpi_status status;
 572
 573        if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
 574                return 1;
 575
 576        if (ares->data.common_serial_bus.type != ACPI_RESOURCE_SERIAL_TYPE_UART)
 577                return 1;
 578
 579        if (lookup->index != -1 && lookup->n++ != lookup->index)
 580                return 1;
 581
 582        sb = &ares->data.uart_serial_bus;
 583
 584        status = acpi_get_handle(lookup->device_handle,
 585                                 sb->resource_source.string_ptr,
 586                                 &lookup->controller_handle);
 587        if (ACPI_FAILURE(status))
 588                return 1;
 589
 590        /*
 591         * NOTE: Ideally, we would also want to retreive other properties here,
 592         * once setting them before opening the device is supported by serdev.
 593         */
 594
 595        return 1;
 596}
 597
 598static int acpi_serdev_do_lookup(struct acpi_device *adev,
 599                                 struct acpi_serdev_lookup *lookup)
 600{
 601        struct list_head resource_list;
 602        int ret;
 603
 604        lookup->device_handle = acpi_device_handle(adev);
 605        lookup->controller_handle = NULL;
 606        lookup->n = 0;
 607
 608        INIT_LIST_HEAD(&resource_list);
 609        ret = acpi_dev_get_resources(adev, &resource_list,
 610                                     acpi_serdev_parse_resource, lookup);
 611        acpi_dev_free_resource_list(&resource_list);
 612
 613        if (ret < 0)
 614                return -EINVAL;
 615
 616        return 0;
 617}
 618
 619static int acpi_serdev_check_resources(struct serdev_controller *ctrl,
 620                                       struct acpi_device *adev)
 621{
 622        struct acpi_serdev_lookup lookup;
 623        int ret;
 624
 625        if (acpi_bus_get_status(adev) || !adev->status.present)
 626                return -EINVAL;
 627
 628        /* Look for UARTSerialBusV2 resource */
 629        lookup.index = -1;      // we only care for the last device
 630
 631        ret = acpi_serdev_do_lookup(adev, &lookup);
 632        if (ret)
 633                return ret;
 634
 635        /*
 636         * Apple machines provide an empty resource template, so on those
 637         * machines just look for immediate children with a "baud" property
 638         * (from the _DSM method) instead.
 639         */
 640        if (!lookup.controller_handle && x86_apple_machine &&
 641            !acpi_dev_get_property(adev, "baud", ACPI_TYPE_BUFFER, NULL))
 642                acpi_get_parent(adev->handle, &lookup.controller_handle);
 643
 644        /* Make sure controller and ResourceSource handle match */
 645        if (ACPI_HANDLE(ctrl->dev.parent) != lookup.controller_handle)
 646                return -ENODEV;
 647
 648        return 0;
 649}
 650
 651static acpi_status acpi_serdev_register_device(struct serdev_controller *ctrl,
 652                                               struct acpi_device *adev)
 653{
 654        struct serdev_device *serdev;
 655        int err;
 656
 657        serdev = serdev_device_alloc(ctrl);
 658        if (!serdev) {
 659                dev_err(&ctrl->dev, "failed to allocate serdev device for %s\n",
 660                        dev_name(&adev->dev));
 661                return AE_NO_MEMORY;
 662        }
 663
 664        ACPI_COMPANION_SET(&serdev->dev, adev);
 665        acpi_device_set_enumerated(adev);
 666
 667        err = serdev_device_add(serdev);
 668        if (err) {
 669                dev_err(&serdev->dev,
 670                        "failure adding ACPI serdev device. status %pe\n",
 671                        ERR_PTR(err));
 672                serdev_device_put(serdev);
 673        }
 674
 675        return AE_OK;
 676}
 677
 678static const struct acpi_device_id serdev_acpi_devices_blacklist[] = {
 679        { "INT3511", 0 },
 680        { "INT3512", 0 },
 681        { },
 682};
 683
 684static acpi_status acpi_serdev_add_device(acpi_handle handle, u32 level,
 685                                          void *data, void **return_value)
 686{
 687        struct serdev_controller *ctrl = data;
 688        struct acpi_device *adev;
 689
 690        if (acpi_bus_get_device(handle, &adev))
 691                return AE_OK;
 692
 693        if (acpi_device_enumerated(adev))
 694                return AE_OK;
 695
 696        /* Skip if black listed */
 697        if (!acpi_match_device_ids(adev, serdev_acpi_devices_blacklist))
 698                return AE_OK;
 699
 700        if (acpi_serdev_check_resources(ctrl, adev))
 701                return AE_OK;
 702
 703        return acpi_serdev_register_device(ctrl, adev);
 704}
 705
 706
 707static int acpi_serdev_register_devices(struct serdev_controller *ctrl)
 708{
 709        acpi_status status;
 710
 711        if (!has_acpi_companion(ctrl->dev.parent))
 712                return -ENODEV;
 713
 714        status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 715                                     SERDEV_ACPI_MAX_SCAN_DEPTH,
 716                                     acpi_serdev_add_device, NULL, ctrl, NULL);
 717        if (ACPI_FAILURE(status))
 718                dev_warn(&ctrl->dev, "failed to enumerate serdev slaves\n");
 719
 720        if (!ctrl->serdev)
 721                return -ENODEV;
 722
 723        return 0;
 724}
 725#else
 726static inline int acpi_serdev_register_devices(struct serdev_controller *ctrl)
 727{
 728        return -ENODEV;
 729}
 730#endif /* CONFIG_ACPI */
 731
 732/**
 733 * serdev_controller_add() - Add an serdev controller
 734 * @ctrl:       controller to be registered.
 735 *
 736 * Register a controller previously allocated via serdev_controller_alloc() with
 737 * the serdev core.
 738 */
 739int serdev_controller_add(struct serdev_controller *ctrl)
 740{
 741        int ret_of, ret_acpi, ret;
 742
 743        /* Can't register until after driver model init */
 744        if (WARN_ON(!is_registered))
 745                return -EAGAIN;
 746
 747        ret = device_add(&ctrl->dev);
 748        if (ret)
 749                return ret;
 750
 751        pm_runtime_enable(&ctrl->dev);
 752
 753        ret_of = of_serdev_register_devices(ctrl);
 754        ret_acpi = acpi_serdev_register_devices(ctrl);
 755        if (ret_of && ret_acpi) {
 756                dev_dbg(&ctrl->dev, "no devices registered: of:%pe acpi:%pe\n",
 757                        ERR_PTR(ret_of), ERR_PTR(ret_acpi));
 758                ret = -ENODEV;
 759                goto err_rpm_disable;
 760        }
 761
 762        dev_dbg(&ctrl->dev, "serdev%d registered: dev:%p\n",
 763                ctrl->nr, &ctrl->dev);
 764        return 0;
 765
 766err_rpm_disable:
 767        pm_runtime_disable(&ctrl->dev);
 768        device_del(&ctrl->dev);
 769        return ret;
 770};
 771EXPORT_SYMBOL_GPL(serdev_controller_add);
 772
 773/* Remove a device associated with a controller */
 774static int serdev_remove_device(struct device *dev, void *data)
 775{
 776        struct serdev_device *serdev = to_serdev_device(dev);
 777        if (dev->type == &serdev_device_type)
 778                serdev_device_remove(serdev);
 779        return 0;
 780}
 781
 782/**
 783 * serdev_controller_remove(): remove an serdev controller
 784 * @ctrl:       controller to remove
 785 *
 786 * Remove a serdev controller.  Caller is responsible for calling
 787 * serdev_controller_put() to discard the allocated controller.
 788 */
 789void serdev_controller_remove(struct serdev_controller *ctrl)
 790{
 791        if (!ctrl)
 792                return;
 793
 794        device_for_each_child(&ctrl->dev, NULL, serdev_remove_device);
 795        pm_runtime_disable(&ctrl->dev);
 796        device_del(&ctrl->dev);
 797}
 798EXPORT_SYMBOL_GPL(serdev_controller_remove);
 799
 800/**
 801 * __serdev_device_driver_register() - Register client driver with serdev core
 802 * @sdrv:       client driver to be associated with client-device.
 803 * @owner:      client driver owner to set.
 804 *
 805 * This API will register the client driver with the serdev framework.
 806 * It is typically called from the driver's module-init function.
 807 */
 808int __serdev_device_driver_register(struct serdev_device_driver *sdrv, struct module *owner)
 809{
 810        sdrv->driver.bus = &serdev_bus_type;
 811        sdrv->driver.owner = owner;
 812
 813        /* force drivers to async probe so I/O is possible in probe */
 814        sdrv->driver.probe_type = PROBE_PREFER_ASYNCHRONOUS;
 815
 816        return driver_register(&sdrv->driver);
 817}
 818EXPORT_SYMBOL_GPL(__serdev_device_driver_register);
 819
 820static void __exit serdev_exit(void)
 821{
 822        bus_unregister(&serdev_bus_type);
 823        ida_destroy(&ctrl_ida);
 824}
 825module_exit(serdev_exit);
 826
 827static int __init serdev_init(void)
 828{
 829        int ret;
 830
 831        ret = bus_register(&serdev_bus_type);
 832        if (ret)
 833                return ret;
 834
 835        is_registered = true;
 836        return 0;
 837}
 838/* Must be before serial drivers register */
 839postcore_initcall(serdev_init);
 840
 841MODULE_AUTHOR("Rob Herring <robh@kernel.org>");
 842MODULE_LICENSE("GPL v2");
 843MODULE_DESCRIPTION("Serial attached device bus");
 844