drivers/hsi/hsi_core.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * HSI core.
   4  *
   5  * Copyright (C) 2010 Nokia Corporation. All rights reserved.
   6  *
   7  * Contact: Carlos Chinea <carlos.chinea@nokia.com>
   8  */
   9 #include <linux/hsi/hsi.h>
  10 #include <linux/compiler.h>
  11 #include <linux/list.h>
  12 #include <linux/kobject.h>
  13 #include <linux/slab.h>
  14 #include <linux/string.h>
  15 #include <linux/notifier.h>
  16 #include <linux/of.h>
  17 #include <linux/of_device.h>
  18 #include "hsi_core.h"
  19
  20 static ssize_t modalias_show(struct device *dev,
  21                         struct device_attribute *a __maybe_unused, char *buf)
  22 {
  23         return sprintf(buf, "hsi:%s\n", dev_name(dev));
  24 }
  25 static DEVICE_ATTR_RO(modalias);
  26
  27 static struct attribute *hsi_bus_dev_attrs[] = {
  28         &dev_attr_modalias.attr,
  29         NULL,
  30 };
  31 ATTRIBUTE_GROUPS(hsi_bus_dev);
  32
  33 static int hsi_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
  34 {
  35         add_uevent_var(env, "MODALIAS=hsi:%s", dev_name(dev));
  36
  37         return 0;
  38 }
  39
  40 static int hsi_bus_match(struct device *dev, struct device_driver *driver)
  41 {
  42         if (of_driver_match_device(dev, driver))
  43                 return true;
  44
  45         if (strcmp(dev_name(dev), driver->name) == 0)
  46                 return true;
  47
  48         return false;
  49 }
  50
  51 static struct bus_type hsi_bus_type = {
  52         .name           = "hsi",
  53         .dev_groups     = hsi_bus_dev_groups,
  54         .match          = hsi_bus_match,
  55         .uevent         = hsi_bus_uevent,
  56 };
  57
  58 static void hsi_client_release(struct device *dev)
  59 {
  60         struct hsi_client *cl = to_hsi_client(dev);
  61
  62         kfree(cl->tx_cfg.channels);
  63         kfree(cl->rx_cfg.channels);
  64         kfree(cl);
  65 }
  66
  67 struct hsi_client *hsi_new_client(struct hsi_port *port,
  68                                                 struct hsi_board_info *info)
  69 {
  70         struct hsi_client *cl;
  71         size_t size;
  72
  73         cl = kzalloc(sizeof(*cl), GFP_KERNEL);
  74         if (!cl)
  75                 goto err;
  76
  77         cl->tx_cfg = info->tx_cfg;
  78         if (cl->tx_cfg.channels) {
  79                 size = cl->tx_cfg.num_channels * sizeof(*cl->tx_cfg.channels);
  80                 cl->tx_cfg.channels = kmemdup(info->tx_cfg.channels, size,
  81                                               GFP_KERNEL);
  82                 if (!cl->tx_cfg.channels)
  83                         goto err_tx;
  84         }
  85
  86         cl->rx_cfg = info->rx_cfg;
  87         if (cl->rx_cfg.channels) {
  88                 size = cl->rx_cfg.num_channels * sizeof(*cl->rx_cfg.channels);
  89                 cl->rx_cfg.channels = kmemdup(info->rx_cfg.channels, size,
  90                                               GFP_KERNEL);
  91                 if (!cl->rx_cfg.channels)
  92                         goto err_rx;
  93         }
  94
  95         cl->device.bus = &hsi_bus_type;
  96         cl->device.parent = &port->device;
  97         cl->device.release = hsi_client_release;
  98         dev_set_name(&cl->device, "%s", info->name);
  99         cl->device.platform_data = info->platform_data;
 100         if (info->archdata)
 101                 cl->device.archdata = *info->archdata;
 102         if (device_register(&cl->device) < 0) {
 103                 pr_err("hsi: failed to register client: %s\n", info->name);
 104                 put_device(&cl->device);
 105         }
 106
 107         return cl;
 108 err_rx:
 109         kfree(cl->tx_cfg.channels);
 110 err_tx:
 111         kfree(cl);
 112 err:
 113         return NULL;
 114 }
 115 EXPORT_SYMBOL_GPL(hsi_new_client);
 116
 117 static void hsi_scan_board_info(struct hsi_controller *hsi)
 118 {
 119         struct hsi_cl_info *cl_info;
 120         struct hsi_port *p;
 121
 122         list_for_each_entry(cl_info, &hsi_board_list, list)
 123                 if (cl_info->info.hsi_id == hsi->id) {
 124                         p = hsi_find_port_num(hsi, cl_info->info.port);
 125                         if (!p)
 126                                 continue;
 127                         hsi_new_client(p, &cl_info->info);
 128                 }
 129 }
 130
 131 #ifdef CONFIG_OF
 132 static struct hsi_board_info hsi_char_dev_info = {
 133         .name = "hsi_char",
 134 };
 135
 136 static int hsi_of_property_parse_mode(struct device_node *client, char *name,
 137                                       unsigned int *result)
 138 {
 139         const char *mode;
 140         int err;
 141
 142         err = of_property_read_string(client, name, &mode);
 143         if (err < 0)
 144                 return err;
 145
 146         if (strcmp(mode, "stream") == 0)
 147                 *result = HSI_MODE_STREAM;
 148         else if (strcmp(mode, "frame") == 0)
 149                 *result = HSI_MODE_FRAME;
 150         else
 151                 return -EINVAL;
 152
 153         return 0;
 154 }
 155
 156 static int hsi_of_property_parse_flow(struct device_node *client, char *name,
 157                                       unsigned int *result)
 158 {
 159         const char *flow;
 160         int err;
 161
 162         err = of_property_read_string(client, name, &flow);
 163         if (err < 0)
 164                 return err;
 165
 166         if (strcmp(flow, "synchronized") == 0)
 167                 *result = HSI_FLOW_SYNC;
 168         else if (strcmp(flow, "pipeline") == 0)
 169                 *result = HSI_FLOW_PIPE;
 170         else
 171                 return -EINVAL;
 172
 173         return 0;
 174 }
 175
 176 static int hsi_of_property_parse_arb_mode(struct device_node *client,
 177                                           char *name, unsigned int *result)
 178 {
 179         const char *arb_mode;
 180         int err;
 181
 182         err = of_property_read_string(client, name, &arb_mode);
 183         if (err < 0)
 184                 return err;
 185
 186         if (strcmp(arb_mode, "round-robin") == 0)
 187                 *result = HSI_ARB_RR;
 188         else if (strcmp(arb_mode, "priority") == 0)
 189                 *result = HSI_ARB_PRIO;
 190         else
 191                 return -EINVAL;
 192
 193         return 0;
 194 }
 195
 196 static void hsi_add_client_from_dt(struct hsi_port *port,
 197                                                 struct device_node *client)
 198 {
 199         struct hsi_client *cl;
 200         struct hsi_channel channel;
 201         struct property *prop;
 202         char name[32];
 203         int length, cells, err, i, max_chan, mode;
 204
 205         cl = kzalloc(sizeof(*cl), GFP_KERNEL);
 206         if (!cl)
 207                 return;
 208
 209         err = of_modalias_node(client, name, sizeof(name));
 210         if (err)
 211                 goto err;
 212
 213         dev_set_name(&cl->device, "%s", name);
 214
 215         err = hsi_of_property_parse_mode(client, "hsi-mode", &mode);
 216         if (err) {
 217                 err = hsi_of_property_parse_mode(client, "hsi-rx-mode",
 218                                                  &cl->rx_cfg.mode);
 219                 if (err)
 220                         goto err;
 221
 222                 err = hsi_of_property_parse_mode(client, "hsi-tx-mode",
 223                                                  &cl->tx_cfg.mode);
 224                 if (err)
 225                         goto err;
 226         } else {
 227                 cl->rx_cfg.mode = mode;
 228                 cl->tx_cfg.mode = mode;
 229         }
 230
 231         err = of_property_read_u32(client, "hsi-speed-kbps",
 232                                    &cl->tx_cfg.speed);
 233         if (err)
 234                 goto err;
 235         cl->rx_cfg.speed = cl->tx_cfg.speed;
 236
 237         err = hsi_of_property_parse_flow(client, "hsi-flow",
 238                                          &cl->rx_cfg.flow);
 239         if (err)
 240                 goto err;
 241
 242         err = hsi_of_property_parse_arb_mode(client, "hsi-arb-mode",
 243                                              &cl->rx_cfg.arb_mode);
 244         if (err)
 245                 goto err;
 246
 247         prop = of_find_property(client, "hsi-channel-ids", &length);
 248         if (!prop) {
 249                 err = -EINVAL;
 250                 goto err;
 251         }
 252
 253         cells = length / sizeof(u32);
 254
 255         cl->rx_cfg.num_channels = cells;
 256         cl->tx_cfg.num_channels = cells;
 257         cl->rx_cfg.channels = kcalloc(cells, sizeof(channel), GFP_KERNEL);
 258         if (!cl->rx_cfg.channels) {
 259                 err = -ENOMEM;
 260                 goto err;
 261         }
 262
 263         cl->tx_cfg.channels = kcalloc(cells, sizeof(channel), GFP_KERNEL);
 264         if (!cl->tx_cfg.channels) {
 265                 err = -ENOMEM;
 266                 goto err2;
 267         }
 268
 269         max_chan = 0;
 270         for (i = 0; i < cells; i++) {
 271                 err = of_property_read_u32_index(client, "hsi-channel-ids", i,
 272                                                  &channel.id);
 273                 if (err)
 274                         goto err3;
 275
 276                 err = of_property_read_string_index(client, "hsi-channel-names",
 277                                                     i, &channel.name);
 278                 if (err)
 279                         channel.name = NULL;
 280
 281                 if (channel.id > max_chan)
 282                         max_chan = channel.id;
 283
 284                 cl->rx_cfg.channels[i] = channel;
 285                 cl->tx_cfg.channels[i] = channel;
 286         }
 287
 288         cl->rx_cfg.num_hw_channels = max_chan + 1;
 289         cl->tx_cfg.num_hw_channels = max_chan + 1;
 290
 291         cl->device.bus = &hsi_bus_type;
 292         cl->device.parent = &port->device;
 293         cl->device.release = hsi_client_release;
 294         cl->device.of_node = client;
 295
 296         if (device_register(&cl->device) < 0) {
 297                 pr_err("hsi: failed to register client: %s\n", name);
 298                 put_device(&cl->device);
 299         }
 300
 301         return;
 302
 303 err3:
 304         kfree(cl->tx_cfg.channels);
 305 err2:
 306         kfree(cl->rx_cfg.channels);
 307 err:
 308         kfree(cl);
 309         pr_err("hsi client: missing or incorrect of property: err=%d\n", err);
 310 }
 311
 312 void hsi_add_clients_from_dt(struct hsi_port *port, struct device_node *clients)
 313 {
 314         struct device_node *child;
 315
 316         /* register hsi-char device */
 317         hsi_new_client(port, &hsi_char_dev_info);
 318
 319         for_each_available_child_of_node(clients, child)
 320                 hsi_add_client_from_dt(port, child);
 321 }
 322 EXPORT_SYMBOL_GPL(hsi_add_clients_from_dt);
 323 #endif
 324
 325 int hsi_remove_client(struct device *dev, void *data __maybe_unused)
 326 {
 327         device_unregister(dev);
 328
 329         return 0;
 330 }
 331 EXPORT_SYMBOL_GPL(hsi_remove_client);
 332
 333 static int hsi_remove_port(struct device *dev, void *data __maybe_unused)
 334 {
 335         device_for_each_child(dev, NULL, hsi_remove_client);
 336         device_unregister(dev);
 337
 338         return 0;
 339 }
 340
 341 static void hsi_controller_release(struct device *dev)
 342 {
 343         struct hsi_controller *hsi = to_hsi_controller(dev);
 344
 345         kfree(hsi->port);
 346         kfree(hsi);
 347 }
 348
 349 static void hsi_port_release(struct device *dev)
 350 {
 351         kfree(to_hsi_port(dev));
 352 }
 353
 354 /**
 355  * hsi_port_unregister_clients - Unregister an HSI port
 356  * @port: The HSI port to unregister
 357  */
 358 void hsi_port_unregister_clients(struct hsi_port *port)
 359 {
 360         device_for_each_child(&port->device, NULL, hsi_remove_client);
 361 }
 362 EXPORT_SYMBOL_GPL(hsi_port_unregister_clients);
 363
 364 /**
 365  * hsi_unregister_controller - Unregister an HSI controller
 366  * @hsi: The HSI controller to register
 367  */
 368 void hsi_unregister_controller(struct hsi_controller *hsi)
 369 {
 370         device_for_each_child(&hsi->device, NULL, hsi_remove_port);
 371         device_unregister(&hsi->device);
 372 }
 373 EXPORT_SYMBOL_GPL(hsi_unregister_controller);
 374
 375 /**
 376  * hsi_register_controller - Register an HSI controller and its ports
 377  * @hsi: The HSI controller to register
 378  *
 379  * Returns -errno on failure, 0 on success.
 380  */
 381 int hsi_register_controller(struct hsi_controller *hsi)
 382 {
 383         unsigned int i;
 384         int err;
 385
 386         err = device_add(&hsi->device);
 387         if (err < 0)
 388                 return err;
 389         for (i = 0; i < hsi->num_ports; i++) {
 390                 hsi->port[i]->device.parent = &hsi->device;
 391                 err = device_add(&hsi->port[i]->device);
 392                 if (err < 0)
 393                         goto out;
 394         }
 395         /* Populate HSI bus with HSI clients */
 396         hsi_scan_board_info(hsi);
 397
 398         return 0;
 399 out:
 400         while (i-- > 0)
 401                 device_del(&hsi->port[i]->device);
 402         device_del(&hsi->device);
 403
 404         return err;
 405 }
 406 EXPORT_SYMBOL_GPL(hsi_register_controller);
 407
 408 /**
 409  * hsi_register_client_driver - Register an HSI client to the HSI bus
 410  * @drv: HSI client driver to register
 411  *
 412  * Returns -errno on failure, 0 on success.
 413  */
 414 int hsi_register_client_driver(struct hsi_client_driver *drv)
 415 {
 416         drv->driver.bus = &hsi_bus_type;
 417
 418         return driver_register(&drv->driver);
 419 }
 420 EXPORT_SYMBOL_GPL(hsi_register_client_driver);
 421
 422 static inline int hsi_dummy_msg(struct hsi_msg *msg __maybe_unused)
 423 {
 424         return 0;
 425 }
 426
 427 static inline int hsi_dummy_cl(struct hsi_client *cl __maybe_unused)
 428 {
 429         return 0;
 430 }
 431
 432 /**
 433  * hsi_put_controller - Free an HSI controller
 434  *
 435  * @hsi: Pointer to the HSI controller to freed
 436  *
 437  * HSI controller drivers should only use this function if they need
 438  * to free their allocated hsi_controller structures before a successful
 439  * call to hsi_register_controller. Other use is not allowed.
 440  */
 441 void hsi_put_controller(struct hsi_controller *hsi)
 442 {
 443         unsigned int i;
 444
 445         if (!hsi)
 446                 return;
 447
 448         for (i = 0; i < hsi->num_ports; i++)
 449                 if (hsi->port && hsi->port[i])
 450                         put_device(&hsi->port[i]->device);
 451         put_device(&hsi->device);
 452 }
 453 EXPORT_SYMBOL_GPL(hsi_put_controller);
 454
 455 /**
 456  * hsi_alloc_controller - Allocate an HSI controller and its ports
 457  * @n_ports: Number of ports on the HSI controller
 458  * @flags: Kernel allocation flags
 459  *
 460  * Return NULL on failure or a pointer to an hsi_controller on success.
 461  */
 462 struct hsi_controller *hsi_alloc_controller(unsigned int n_ports, gfp_t flags)
 463 {
 464         struct hsi_controller   *hsi;
 465         struct hsi_port         **port;
 466         unsigned int            i;
 467
 468         if (!n_ports)
 469                 return NULL;
 470
 471         hsi = kzalloc(sizeof(*hsi), flags);
 472         if (!hsi)
 473                 return NULL;
 474         port = kcalloc(n_ports, sizeof(*port), flags);
 475         if (!port) {
 476                 kfree(hsi);
 477                 return NULL;
 478         }
 479         hsi->num_ports = n_ports;
 480         hsi->port = port;
 481         hsi->device.release = hsi_controller_release;
 482         device_initialize(&hsi->device);
 483
 484         for (i = 0; i < n_ports; i++) {
 485                 port[i] = kzalloc(sizeof(**port), flags);
 486                 if (port[i] == NULL)
 487                         goto out;
 488                 port[i]->num = i;
 489                 port[i]->async = hsi_dummy_msg;
 490                 port[i]->setup = hsi_dummy_cl;
 491                 port[i]->flush = hsi_dummy_cl;
 492                 port[i]->start_tx = hsi_dummy_cl;
 493                 port[i]->stop_tx = hsi_dummy_cl;
 494                 port[i]->release = hsi_dummy_cl;
 495                 mutex_init(&port[i]->lock);
 496                 BLOCKING_INIT_NOTIFIER_HEAD(&port[i]->n_head);
 497                 dev_set_name(&port[i]->device, "port%d", i);
 498                 hsi->port[i]->device.release = hsi_port_release;
 499                 device_initialize(&hsi->port[i]->device);
 500         }
 501
 502         return hsi;
 503 out:
 504         hsi_put_controller(hsi);
 505
 506         return NULL;
 507 }
 508 EXPORT_SYMBOL_GPL(hsi_alloc_controller);
 509
 510 /**
 511  * hsi_free_msg - Free an HSI message
 512  * @msg: Pointer to the HSI message
 513  *
 514  * Client is responsible to free the buffers pointed by the scatterlists.
 515  */
 516 void hsi_free_msg(struct hsi_msg *msg)
 517 {
 518         if (!msg)
 519                 return;
 520         sg_free_table(&msg->sgt);
 521         kfree(msg);
 522 }
 523 EXPORT_SYMBOL_GPL(hsi_free_msg);
 524
 525 /**
 526  * hsi_alloc_msg - Allocate an HSI message
 527  * @nents: Number of memory entries
 528  * @flags: Kernel allocation flags
 529  *
 530  * nents can be 0. This mainly makes sense for read transfer.
 531  * In that case, HSI drivers will call the complete callback when
 532  * there is data to be read without consuming it.
 533  *
 534  * Return NULL on failure or a pointer to an hsi_msg on success.
 535  */
 536 struct hsi_msg *hsi_alloc_msg(unsigned int nents, gfp_t flags)
 537 {
 538         struct hsi_msg *msg;
 539         int err;
 540
 541         msg = kzalloc(sizeof(*msg), flags);
 542         if (!msg)
 543                 return NULL;
 544
 545         if (!nents)
 546                 return msg;
 547
 548         err = sg_alloc_table(&msg->sgt, nents, flags);
 549         if (unlikely(err)) {
 550                 kfree(msg);
 551                 msg = NULL;
 552         }
 553
 554         return msg;
 555 }
 556 EXPORT_SYMBOL_GPL(hsi_alloc_msg);
 557
 558 /**
 559  * hsi_async - Submit an HSI transfer to the controller
 560  * @cl: HSI client sending the transfer
 561  * @msg: The HSI transfer passed to controller
 562  *
 563  * The HSI message must have the channel, ttype, complete and destructor
 564  * fields set beforehand. If nents > 0 then the client has to initialize
 565  * also the scatterlists to point to the buffers to write to or read from.
 566  *
 567  * HSI controllers relay on pre-allocated buffers from their clients and they
 568  * do not allocate buffers on their own.
 569  *
 570  * Once the HSI message transfer finishes, the HSI controller calls the
 571  * complete callback with the status and actual_len fields of the HSI message
 572  * updated. The complete callback can be called before returning from
 573  * hsi_async.
 574  *
 575  * Returns -errno on failure or 0 on success
 576  */
 577 int hsi_async(struct hsi_client *cl, struct hsi_msg *msg)
 578 {
 579         struct hsi_port *port = hsi_get_port(cl);
 580
 581         if (!hsi_port_claimed(cl))
 582                 return -EACCES;
 583
 584         WARN_ON_ONCE(!msg->destructor || !msg->complete);
 585         msg->cl = cl;
 586
 587         return port->async(msg);
 588 }
 589 EXPORT_SYMBOL_GPL(hsi_async);
 590
 591 /**
 592  * hsi_claim_port - Claim the HSI client's port
 593  * @cl: HSI client that wants to claim its port
 594  * @share: Flag to indicate if the client wants to share the port or not.
 595  *
 596  * Returns -errno on failure, 0 on success.
 597  */
 598 int hsi_claim_port(struct hsi_client *cl, unsigned int share)
 599 {
 600         struct hsi_port *port = hsi_get_port(cl);
 601         int err = 0;
 602
 603         mutex_lock(&port->lock);
 604         if ((port->claimed) && (!port->shared || !share)) {
 605                 err = -EBUSY;
 606                 goto out;
 607         }
 608         if (!try_module_get(to_hsi_controller(port->device.parent)->owner)) {
 609                 err = -ENODEV;
 610                 goto out;
 611         }
 612         port->claimed++;
 613         port->shared = !!share;
 614         cl->pclaimed = 1;
 615 out:
 616         mutex_unlock(&port->lock);
 617
 618         return err;
 619 }
 620 EXPORT_SYMBOL_GPL(hsi_claim_port);
 621
 622 /**
 623  * hsi_release_port - Release the HSI client's port
 624  * @cl: HSI client which previously claimed its port
 625  */
 626 void hsi_release_port(struct hsi_client *cl)
 627 {
 628         struct hsi_port *port = hsi_get_port(cl);
 629
 630         mutex_lock(&port->lock);
 631         /* Allow HW driver to do some cleanup */
 632         port->release(cl);
 633         if (cl->pclaimed)
 634                 port->claimed--;
 635         BUG_ON(port->claimed < 0);
 636         cl->pclaimed = 0;
 637         if (!port->claimed)
 638                 port->shared = 0;
 639         module_put(to_hsi_controller(port->device.parent)->owner);
 640         mutex_unlock(&port->lock);
 641 }
 642 EXPORT_SYMBOL_GPL(hsi_release_port);
 643
 644 static int hsi_event_notifier_call(struct notifier_block *nb,
 645                                 unsigned long event, void *data __maybe_unused)
 646 {
 647         struct hsi_client *cl = container_of(nb, struct hsi_client, nb);
 648
 649         (*cl->ehandler)(cl, event);
 650
 651         return 0;
 652 }
 653
 654 /**
 655  * hsi_register_port_event - Register a client to receive port events
 656  * @cl: HSI client that wants to receive port events
 657  * @handler: Event handler callback
 658  *
 659  * Clients should register a callback to be able to receive
 660  * events from the ports. Registration should happen after
 661  * claiming the port.
 662  * The handler can be called in interrupt context.
 663  *
 664  * Returns -errno on error, or 0 on success.
 665  */
 666 int hsi_register_port_event(struct hsi_client *cl,
 667                         void (*handler)(struct hsi_client *, unsigned long))
 668 {
 669         struct hsi_port *port = hsi_get_port(cl);
 670
 671         if (!handler || cl->ehandler)
 672                 return -EINVAL;
 673         if (!hsi_port_claimed(cl))
 674                 return -EACCES;
 675         cl->ehandler = handler;
 676         cl->nb.notifier_call = hsi_event_notifier_call;
 677
 678         return blocking_notifier_chain_register(&port->n_head, &cl->nb);
 679 }
 680 EXPORT_SYMBOL_GPL(hsi_register_port_event);
 681
 682 /**
 683  * hsi_unregister_port_event - Stop receiving port events for a client
 684  * @cl: HSI client that wants to stop receiving port events
 685  *
 686  * Clients should call this function before releasing their associated
 687  * port.
 688  *
 689  * Returns -errno on error, or 0 on success.
 690  */
 691 int hsi_unregister_port_event(struct hsi_client *cl)
 692 {
 693         struct hsi_port *port = hsi_get_port(cl);
 694         int err;
 695
 696         WARN_ON(!hsi_port_claimed(cl));
 697
 698         err = blocking_notifier_chain_unregister(&port->n_head, &cl->nb);
 699         if (!err)
 700                 cl->ehandler = NULL;
 701
 702         return err;
 703 }
 704 EXPORT_SYMBOL_GPL(hsi_unregister_port_event);
 705
 706 /**
 707  * hsi_event - Notifies clients about port events
 708  * @port: Port where the event occurred
 709  * @event: The event type
 710  *
 711  * Clients should not be concerned about wake line behavior. However, due
 712  * to a race condition in HSI HW protocol, clients need to be notified
 713  * about wake line changes, so they can implement a workaround for it.
 714  *
 715  * Events:
 716  * HSI_EVENT_START_RX - Incoming wake line high
 717  * HSI_EVENT_STOP_RX - Incoming wake line down
 718  *
 719  * Returns -errno on error, or 0 on success.
 720  */
 721 int hsi_event(struct hsi_port *port, unsigned long event)
 722 {
 723         return blocking_notifier_call_chain(&port->n_head, event, NULL);
 724 }
 725 EXPORT_SYMBOL_GPL(hsi_event);
 726
 727 /**
 728  * hsi_get_channel_id_by_name - acquire channel id by channel name
 729  * @cl: HSI client, which uses the channel
 730  * @name: name the channel is known under
 731  *
 732  * Clients can call this function to get the hsi channel ids similar to
 733  * requesting IRQs or GPIOs by name. This function assumes the same
 734  * channel configuration is used for RX and TX.
 735  *
 736  * Returns -errno on error or channel id on success.
 737  */
 738 int hsi_get_channel_id_by_name(struct hsi_client *cl, char *name)
 739 {
 740         int i;
 741
 742         if (!cl->rx_cfg.channels)
 743                 return -ENOENT;
 744
 745         for (i = 0; i < cl->rx_cfg.num_channels; i++)
 746                 if (!strcmp(cl->rx_cfg.channels[i].name, name))
 747                         return cl->rx_cfg.channels[i].id;
 748
 749         return -ENXIO;
 750 }
 751 EXPORT_SYMBOL_GPL(hsi_get_channel_id_by_name);
 752
 753 static int __init hsi_init(void)
 754 {
 755         return bus_register(&hsi_bus_type);
 756 }
 757 postcore_initcall(hsi_init);
 758
 759 static void __exit hsi_exit(void)
 760 {
 761         bus_unregister(&hsi_bus_type);
 762 }
 763 module_exit(hsi_exit);
 764
 765 MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
 766 MODULE_DESCRIPTION("High-speed Synchronous Serial Interface (HSI) framework");
 767 MODULE_LICENSE("GPL v2");