drivers/hsi/hsi_core.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * HSI core.
0004  *
0005  * Copyright (C) 2010 Nokia Corporation. All rights reserved.
0006  *
0007  * Contact: Carlos Chinea <carlos.chinea@nokia.com>
0008  */
0009 #include <linux/hsi/hsi.h>
0010 #include <linux/compiler.h>
0011 #include <linux/list.h>
0012 #include <linux/kobject.h>
0013 #include <linux/slab.h>
0014 #include <linux/string.h>
0015 #include <linux/notifier.h>
0016 #include <linux/of.h>
0017 #include <linux/of_device.h>
0018 #include "hsi_core.h"
0019
0020 static ssize_t modalias_show(struct device *dev,
0021             struct device_attribute *a __maybe_unused, char *buf)
0022 {
0023     return sprintf(buf, "hsi:%s\n", dev_name(dev));
0024 }
0025 static DEVICE_ATTR_RO(modalias);
0026
0027 static struct attribute *hsi_bus_dev_attrs[] = {
0028     &dev_attr_modalias.attr,
0029     NULL,
0030 };
0031 ATTRIBUTE_GROUPS(hsi_bus_dev);
0032
0033 static int hsi_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
0034 {
0035     add_uevent_var(env, "MODALIAS=hsi:%s", dev_name(dev));
0036
0037     return 0;
0038 }
0039
0040 static int hsi_bus_match(struct device *dev, struct device_driver *driver)
0041 {
0042     if (of_driver_match_device(dev, driver))
0043         return true;
0044
0045     if (strcmp(dev_name(dev), driver->name) == 0)
0046         return true;
0047
0048     return false;
0049 }
0050
0051 static struct bus_type hsi_bus_type = {
0052     .name       = "hsi",
0053     .dev_groups = hsi_bus_dev_groups,
0054     .match      = hsi_bus_match,
0055     .uevent     = hsi_bus_uevent,
0056 };
0057
0058 static void hsi_client_release(struct device *dev)
0059 {
0060     struct hsi_client *cl = to_hsi_client(dev);
0061
0062     kfree(cl->tx_cfg.channels);
0063     kfree(cl->rx_cfg.channels);
0064     kfree(cl);
0065 }
0066
0067 struct hsi_client *hsi_new_client(struct hsi_port *port,
0068                         struct hsi_board_info *info)
0069 {
0070     struct hsi_client *cl;
0071     size_t size;
0072
0073     cl = kzalloc(sizeof(*cl), GFP_KERNEL);
0074     if (!cl)
0075         goto err;
0076
0077     cl->tx_cfg = info->tx_cfg;
0078     if (cl->tx_cfg.channels) {
0079         size = cl->tx_cfg.num_channels * sizeof(*cl->tx_cfg.channels);
0080         cl->tx_cfg.channels = kmemdup(info->tx_cfg.channels, size,
0081                           GFP_KERNEL);
0082         if (!cl->tx_cfg.channels)
0083             goto err_tx;
0084     }
0085
0086     cl->rx_cfg = info->rx_cfg;
0087     if (cl->rx_cfg.channels) {
0088         size = cl->rx_cfg.num_channels * sizeof(*cl->rx_cfg.channels);
0089         cl->rx_cfg.channels = kmemdup(info->rx_cfg.channels, size,
0090                           GFP_KERNEL);
0091         if (!cl->rx_cfg.channels)
0092             goto err_rx;
0093     }
0094
0095     cl->device.bus = &hsi_bus_type;
0096     cl->device.parent = &port->device;
0097     cl->device.release = hsi_client_release;
0098     dev_set_name(&cl->device, "%s", info->name);
0099     cl->device.platform_data = info->platform_data;
0100     if (info->archdata)
0101         cl->device.archdata = *info->archdata;
0102     if (device_register(&cl->device) < 0) {
0103         pr_err("hsi: failed to register client: %s\n", info->name);
0104         put_device(&cl->device);
0105         goto err;
0106     }
0107
0108     return cl;
0109 err_rx:
0110     kfree(cl->tx_cfg.channels);
0111 err_tx:
0112     kfree(cl);
0113 err:
0114     return NULL;
0115 }
0116 EXPORT_SYMBOL_GPL(hsi_new_client);
0117
0118 static void hsi_scan_board_info(struct hsi_controller *hsi)
0119 {
0120     struct hsi_cl_info *cl_info;
0121     struct hsi_port *p;
0122
0123     list_for_each_entry(cl_info, &hsi_board_list, list)
0124         if (cl_info->info.hsi_id == hsi->id) {
0125             p = hsi_find_port_num(hsi, cl_info->info.port);
0126             if (!p)
0127                 continue;
0128             hsi_new_client(p, &cl_info->info);
0129         }
0130 }
0131
0132 #ifdef CONFIG_OF
0133 static struct hsi_board_info hsi_char_dev_info = {
0134     .name = "hsi_char",
0135 };
0136
0137 static int hsi_of_property_parse_mode(struct device_node *client, char *name,
0138                       unsigned int *result)
0139 {
0140     const char *mode;
0141     int err;
0142
0143     err = of_property_read_string(client, name, &mode);
0144     if (err < 0)
0145         return err;
0146
0147     if (strcmp(mode, "stream") == 0)
0148         *result = HSI_MODE_STREAM;
0149     else if (strcmp(mode, "frame") == 0)
0150         *result = HSI_MODE_FRAME;
0151     else
0152         return -EINVAL;
0153
0154     return 0;
0155 }
0156
0157 static int hsi_of_property_parse_flow(struct device_node *client, char *name,
0158                       unsigned int *result)
0159 {
0160     const char *flow;
0161     int err;
0162
0163     err = of_property_read_string(client, name, &flow);
0164     if (err < 0)
0165         return err;
0166
0167     if (strcmp(flow, "synchronized") == 0)
0168         *result = HSI_FLOW_SYNC;
0169     else if (strcmp(flow, "pipeline") == 0)
0170         *result = HSI_FLOW_PIPE;
0171     else
0172         return -EINVAL;
0173
0174     return 0;
0175 }
0176
0177 static int hsi_of_property_parse_arb_mode(struct device_node *client,
0178                       char *name, unsigned int *result)
0179 {
0180     const char *arb_mode;
0181     int err;
0182
0183     err = of_property_read_string(client, name, &arb_mode);
0184     if (err < 0)
0185         return err;
0186
0187     if (strcmp(arb_mode, "round-robin") == 0)
0188         *result = HSI_ARB_RR;
0189     else if (strcmp(arb_mode, "priority") == 0)
0190         *result = HSI_ARB_PRIO;
0191     else
0192         return -EINVAL;
0193
0194     return 0;
0195 }
0196
0197 static void hsi_add_client_from_dt(struct hsi_port *port,
0198                         struct device_node *client)
0199 {
0200     struct hsi_client *cl;
0201     struct hsi_channel channel;
0202     struct property *prop;
0203     char name[32];
0204     int length, cells, err, i, max_chan, mode;
0205
0206     cl = kzalloc(sizeof(*cl), GFP_KERNEL);
0207     if (!cl)
0208         return;
0209
0210     err = of_modalias_node(client, name, sizeof(name));
0211     if (err)
0212         goto err;
0213
0214     err = hsi_of_property_parse_mode(client, "hsi-mode", &mode);
0215     if (err) {
0216         err = hsi_of_property_parse_mode(client, "hsi-rx-mode",
0217                          &cl->rx_cfg.mode);
0218         if (err)
0219             goto err;
0220
0221         err = hsi_of_property_parse_mode(client, "hsi-tx-mode",
0222                          &cl->tx_cfg.mode);
0223         if (err)
0224             goto err;
0225     } else {
0226         cl->rx_cfg.mode = mode;
0227         cl->tx_cfg.mode = mode;
0228     }
0229
0230     err = of_property_read_u32(client, "hsi-speed-kbps",
0231                    &cl->tx_cfg.speed);
0232     if (err)
0233         goto err;
0234     cl->rx_cfg.speed = cl->tx_cfg.speed;
0235
0236     err = hsi_of_property_parse_flow(client, "hsi-flow",
0237                      &cl->rx_cfg.flow);
0238     if (err)
0239         goto err;
0240
0241     err = hsi_of_property_parse_arb_mode(client, "hsi-arb-mode",
0242                          &cl->rx_cfg.arb_mode);
0243     if (err)
0244         goto err;
0245
0246     prop = of_find_property(client, "hsi-channel-ids", &length);
0247     if (!prop) {
0248         err = -EINVAL;
0249         goto err;
0250     }
0251
0252     cells = length / sizeof(u32);
0253
0254     cl->rx_cfg.num_channels = cells;
0255     cl->tx_cfg.num_channels = cells;
0256     cl->rx_cfg.channels = kcalloc(cells, sizeof(channel), GFP_KERNEL);
0257     if (!cl->rx_cfg.channels) {
0258         err = -ENOMEM;
0259         goto err;
0260     }
0261
0262     cl->tx_cfg.channels = kcalloc(cells, sizeof(channel), GFP_KERNEL);
0263     if (!cl->tx_cfg.channels) {
0264         err = -ENOMEM;
0265         goto err2;
0266     }
0267
0268     max_chan = 0;
0269     for (i = 0; i < cells; i++) {
0270         err = of_property_read_u32_index(client, "hsi-channel-ids", i,
0271                          &channel.id);
0272         if (err)
0273             goto err3;
0274
0275         err = of_property_read_string_index(client, "hsi-channel-names",
0276                             i, &channel.name);
0277         if (err)
0278             channel.name = NULL;
0279
0280         if (channel.id > max_chan)
0281             max_chan = channel.id;
0282
0283         cl->rx_cfg.channels[i] = channel;
0284         cl->tx_cfg.channels[i] = channel;
0285     }
0286
0287     cl->rx_cfg.num_hw_channels = max_chan + 1;
0288     cl->tx_cfg.num_hw_channels = max_chan + 1;
0289
0290     cl->device.bus = &hsi_bus_type;
0291     cl->device.parent = &port->device;
0292     cl->device.release = hsi_client_release;
0293     cl->device.of_node = client;
0294
0295     dev_set_name(&cl->device, "%s", name);
0296     if (device_register(&cl->device) < 0) {
0297         pr_err("hsi: failed to register client: %s\n", name);
0298         put_device(&cl->device);
0299     }
0300
0301     return;
0302
0303 err3:
0304     kfree(cl->tx_cfg.channels);
0305 err2:
0306     kfree(cl->rx_cfg.channels);
0307 err:
0308     kfree(cl);
0309     pr_err("hsi client: missing or incorrect of property: err=%d\n", err);
0310 }
0311
0312 void hsi_add_clients_from_dt(struct hsi_port *port, struct device_node *clients)
0313 {
0314     struct device_node *child;
0315
0316     /* register hsi-char device */
0317     hsi_new_client(port, &hsi_char_dev_info);
0318
0319     for_each_available_child_of_node(clients, child)
0320         hsi_add_client_from_dt(port, child);
0321 }
0322 EXPORT_SYMBOL_GPL(hsi_add_clients_from_dt);
0323 #endif
0324
0325 int hsi_remove_client(struct device *dev, void *data __maybe_unused)
0326 {
0327     device_unregister(dev);
0328
0329     return 0;
0330 }
0331 EXPORT_SYMBOL_GPL(hsi_remove_client);
0332
0333 static int hsi_remove_port(struct device *dev, void *data __maybe_unused)
0334 {
0335     device_for_each_child(dev, NULL, hsi_remove_client);
0336     device_unregister(dev);
0337
0338     return 0;
0339 }
0340
0341 static void hsi_controller_release(struct device *dev)
0342 {
0343     struct hsi_controller *hsi = to_hsi_controller(dev);
0344
0345     kfree(hsi->port);
0346     kfree(hsi);
0347 }
0348
0349 static void hsi_port_release(struct device *dev)
0350 {
0351     kfree(to_hsi_port(dev));
0352 }
0353
0354 /**
0355  * hsi_port_unregister_clients - Unregister an HSI port
0356  * @port: The HSI port to unregister
0357  */
0358 void hsi_port_unregister_clients(struct hsi_port *port)
0359 {
0360     device_for_each_child(&port->device, NULL, hsi_remove_client);
0361 }
0362 EXPORT_SYMBOL_GPL(hsi_port_unregister_clients);
0363
0364 /**
0365  * hsi_unregister_controller - Unregister an HSI controller
0366  * @hsi: The HSI controller to register
0367  */
0368 void hsi_unregister_controller(struct hsi_controller *hsi)
0369 {
0370     device_for_each_child(&hsi->device, NULL, hsi_remove_port);
0371     device_unregister(&hsi->device);
0372 }
0373 EXPORT_SYMBOL_GPL(hsi_unregister_controller);
0374
0375 /**
0376  * hsi_register_controller - Register an HSI controller and its ports
0377  * @hsi: The HSI controller to register
0378  *
0379  * Returns -errno on failure, 0 on success.
0380  */
0381 int hsi_register_controller(struct hsi_controller *hsi)
0382 {
0383     unsigned int i;
0384     int err;
0385
0386     err = device_add(&hsi->device);
0387     if (err < 0)
0388         return err;
0389     for (i = 0; i < hsi->num_ports; i++) {
0390         hsi->port[i]->device.parent = &hsi->device;
0391         err = device_add(&hsi->port[i]->device);
0392         if (err < 0)
0393             goto out;
0394     }
0395     /* Populate HSI bus with HSI clients */
0396     hsi_scan_board_info(hsi);
0397
0398     return 0;
0399 out:
0400     while (i-- > 0)
0401         device_del(&hsi->port[i]->device);
0402     device_del(&hsi->device);
0403
0404     return err;
0405 }
0406 EXPORT_SYMBOL_GPL(hsi_register_controller);
0407
0408 /**
0409  * hsi_register_client_driver - Register an HSI client to the HSI bus
0410  * @drv: HSI client driver to register
0411  *
0412  * Returns -errno on failure, 0 on success.
0413  */
0414 int hsi_register_client_driver(struct hsi_client_driver *drv)
0415 {
0416     drv->driver.bus = &hsi_bus_type;
0417
0418     return driver_register(&drv->driver);
0419 }
0420 EXPORT_SYMBOL_GPL(hsi_register_client_driver);
0421
0422 static inline int hsi_dummy_msg(struct hsi_msg *msg __maybe_unused)
0423 {
0424     return 0;
0425 }
0426
0427 static inline int hsi_dummy_cl(struct hsi_client *cl __maybe_unused)
0428 {
0429     return 0;
0430 }
0431
0432 /**
0433  * hsi_put_controller - Free an HSI controller
0434  *
0435  * @hsi: Pointer to the HSI controller to freed
0436  *
0437  * HSI controller drivers should only use this function if they need
0438  * to free their allocated hsi_controller structures before a successful
0439  * call to hsi_register_controller. Other use is not allowed.
0440  */
0441 void hsi_put_controller(struct hsi_controller *hsi)
0442 {
0443     unsigned int i;
0444
0445     if (!hsi)
0446         return;
0447
0448     for (i = 0; i < hsi->num_ports; i++)
0449         if (hsi->port && hsi->port[i])
0450             put_device(&hsi->port[i]->device);
0451     put_device(&hsi->device);
0452 }
0453 EXPORT_SYMBOL_GPL(hsi_put_controller);
0454
0455 /**
0456  * hsi_alloc_controller - Allocate an HSI controller and its ports
0457  * @n_ports: Number of ports on the HSI controller
0458  * @flags: Kernel allocation flags
0459  *
0460  * Return NULL on failure or a pointer to an hsi_controller on success.
0461  */
0462 struct hsi_controller *hsi_alloc_controller(unsigned int n_ports, gfp_t flags)
0463 {
0464     struct hsi_controller   *hsi;
0465     struct hsi_port     **port;
0466     unsigned int        i;
0467
0468     if (!n_ports)
0469         return NULL;
0470
0471     hsi = kzalloc(sizeof(*hsi), flags);
0472     if (!hsi)
0473         return NULL;
0474     port = kcalloc(n_ports, sizeof(*port), flags);
0475     if (!port) {
0476         kfree(hsi);
0477         return NULL;
0478     }
0479     hsi->num_ports = n_ports;
0480     hsi->port = port;
0481     hsi->device.release = hsi_controller_release;
0482     device_initialize(&hsi->device);
0483
0484     for (i = 0; i < n_ports; i++) {
0485         port[i] = kzalloc(sizeof(**port), flags);
0486         if (port[i] == NULL)
0487             goto out;
0488         port[i]->num = i;
0489         port[i]->async = hsi_dummy_msg;
0490         port[i]->setup = hsi_dummy_cl;
0491         port[i]->flush = hsi_dummy_cl;
0492         port[i]->start_tx = hsi_dummy_cl;
0493         port[i]->stop_tx = hsi_dummy_cl;
0494         port[i]->release = hsi_dummy_cl;
0495         mutex_init(&port[i]->lock);
0496         BLOCKING_INIT_NOTIFIER_HEAD(&port[i]->n_head);
0497         dev_set_name(&port[i]->device, "port%d", i);
0498         hsi->port[i]->device.release = hsi_port_release;
0499         device_initialize(&hsi->port[i]->device);
0500     }
0501
0502     return hsi;
0503 out:
0504     hsi_put_controller(hsi);
0505
0506     return NULL;
0507 }
0508 EXPORT_SYMBOL_GPL(hsi_alloc_controller);
0509
0510 /**
0511  * hsi_free_msg - Free an HSI message
0512  * @msg: Pointer to the HSI message
0513  *
0514  * Client is responsible to free the buffers pointed by the scatterlists.
0515  */
0516 void hsi_free_msg(struct hsi_msg *msg)
0517 {
0518     if (!msg)
0519         return;
0520     sg_free_table(&msg->sgt);
0521     kfree(msg);
0522 }
0523 EXPORT_SYMBOL_GPL(hsi_free_msg);
0524
0525 /**
0526  * hsi_alloc_msg - Allocate an HSI message
0527  * @nents: Number of memory entries
0528  * @flags: Kernel allocation flags
0529  *
0530  * nents can be 0. This mainly makes sense for read transfer.
0531  * In that case, HSI drivers will call the complete callback when
0532  * there is data to be read without consuming it.
0533  *
0534  * Return NULL on failure or a pointer to an hsi_msg on success.
0535  */
0536 struct hsi_msg *hsi_alloc_msg(unsigned int nents, gfp_t flags)
0537 {
0538     struct hsi_msg *msg;
0539     int err;
0540
0541     msg = kzalloc(sizeof(*msg), flags);
0542     if (!msg)
0543         return NULL;
0544
0545     if (!nents)
0546         return msg;
0547
0548     err = sg_alloc_table(&msg->sgt, nents, flags);
0549     if (unlikely(err)) {
0550         kfree(msg);
0551         msg = NULL;
0552     }
0553
0554     return msg;
0555 }
0556 EXPORT_SYMBOL_GPL(hsi_alloc_msg);
0557
0558 /**
0559  * hsi_async - Submit an HSI transfer to the controller
0560  * @cl: HSI client sending the transfer
0561  * @msg: The HSI transfer passed to controller
0562  *
0563  * The HSI message must have the channel, ttype, complete and destructor
0564  * fields set beforehand. If nents > 0 then the client has to initialize
0565  * also the scatterlists to point to the buffers to write to or read from.
0566  *
0567  * HSI controllers relay on pre-allocated buffers from their clients and they
0568  * do not allocate buffers on their own.
0569  *
0570  * Once the HSI message transfer finishes, the HSI controller calls the
0571  * complete callback with the status and actual_len fields of the HSI message
0572  * updated. The complete callback can be called before returning from
0573  * hsi_async.
0574  *
0575  * Returns -errno on failure or 0 on success
0576  */
0577 int hsi_async(struct hsi_client *cl, struct hsi_msg *msg)
0578 {
0579     struct hsi_port *port = hsi_get_port(cl);
0580
0581     if (!hsi_port_claimed(cl))
0582         return -EACCES;
0583
0584     WARN_ON_ONCE(!msg->destructor || !msg->complete);
0585     msg->cl = cl;
0586
0587     return port->async(msg);
0588 }
0589 EXPORT_SYMBOL_GPL(hsi_async);
0590
0591 /**
0592  * hsi_claim_port - Claim the HSI client's port
0593  * @cl: HSI client that wants to claim its port
0594  * @share: Flag to indicate if the client wants to share the port or not.
0595  *
0596  * Returns -errno on failure, 0 on success.
0597  */
0598 int hsi_claim_port(struct hsi_client *cl, unsigned int share)
0599 {
0600     struct hsi_port *port = hsi_get_port(cl);
0601     int err = 0;
0602
0603     mutex_lock(&port->lock);
0604     if ((port->claimed) && (!port->shared || !share)) {
0605         err = -EBUSY;
0606         goto out;
0607     }
0608     if (!try_module_get(to_hsi_controller(port->device.parent)->owner)) {
0609         err = -ENODEV;
0610         goto out;
0611     }
0612     port->claimed++;
0613     port->shared = !!share;
0614     cl->pclaimed = 1;
0615 out:
0616     mutex_unlock(&port->lock);
0617
0618     return err;
0619 }
0620 EXPORT_SYMBOL_GPL(hsi_claim_port);
0621
0622 /**
0623  * hsi_release_port - Release the HSI client's port
0624  * @cl: HSI client which previously claimed its port
0625  */
0626 void hsi_release_port(struct hsi_client *cl)
0627 {
0628     struct hsi_port *port = hsi_get_port(cl);
0629
0630     mutex_lock(&port->lock);
0631     /* Allow HW driver to do some cleanup */
0632     port->release(cl);
0633     if (cl->pclaimed)
0634         port->claimed--;
0635     BUG_ON(port->claimed < 0);
0636     cl->pclaimed = 0;
0637     if (!port->claimed)
0638         port->shared = 0;
0639     module_put(to_hsi_controller(port->device.parent)->owner);
0640     mutex_unlock(&port->lock);
0641 }
0642 EXPORT_SYMBOL_GPL(hsi_release_port);
0643
0644 static int hsi_event_notifier_call(struct notifier_block *nb,
0645                 unsigned long event, void *data __maybe_unused)
0646 {
0647     struct hsi_client *cl = container_of(nb, struct hsi_client, nb);
0648
0649     (*cl->ehandler)(cl, event);
0650
0651     return 0;
0652 }
0653
0654 /**
0655  * hsi_register_port_event - Register a client to receive port events
0656  * @cl: HSI client that wants to receive port events
0657  * @handler: Event handler callback
0658  *
0659  * Clients should register a callback to be able to receive
0660  * events from the ports. Registration should happen after
0661  * claiming the port.
0662  * The handler can be called in interrupt context.
0663  *
0664  * Returns -errno on error, or 0 on success.
0665  */
0666 int hsi_register_port_event(struct hsi_client *cl,
0667             void (*handler)(struct hsi_client *, unsigned long))
0668 {
0669     struct hsi_port *port = hsi_get_port(cl);
0670
0671     if (!handler || cl->ehandler)
0672         return -EINVAL;
0673     if (!hsi_port_claimed(cl))
0674         return -EACCES;
0675     cl->ehandler = handler;
0676     cl->nb.notifier_call = hsi_event_notifier_call;
0677
0678     return blocking_notifier_chain_register(&port->n_head, &cl->nb);
0679 }
0680 EXPORT_SYMBOL_GPL(hsi_register_port_event);
0681
0682 /**
0683  * hsi_unregister_port_event - Stop receiving port events for a client
0684  * @cl: HSI client that wants to stop receiving port events
0685  *
0686  * Clients should call this function before releasing their associated
0687  * port.
0688  *
0689  * Returns -errno on error, or 0 on success.
0690  */
0691 int hsi_unregister_port_event(struct hsi_client *cl)
0692 {
0693     struct hsi_port *port = hsi_get_port(cl);
0694     int err;
0695
0696     WARN_ON(!hsi_port_claimed(cl));
0697
0698     err = blocking_notifier_chain_unregister(&port->n_head, &cl->nb);
0699     if (!err)
0700         cl->ehandler = NULL;
0701
0702     return err;
0703 }
0704 EXPORT_SYMBOL_GPL(hsi_unregister_port_event);
0705
0706 /**
0707  * hsi_event - Notifies clients about port events
0708  * @port: Port where the event occurred
0709  * @event: The event type
0710  *
0711  * Clients should not be concerned about wake line behavior. However, due
0712  * to a race condition in HSI HW protocol, clients need to be notified
0713  * about wake line changes, so they can implement a workaround for it.
0714  *
0715  * Events:
0716  * HSI_EVENT_START_RX - Incoming wake line high
0717  * HSI_EVENT_STOP_RX - Incoming wake line down
0718  *
0719  * Returns -errno on error, or 0 on success.
0720  */
0721 int hsi_event(struct hsi_port *port, unsigned long event)
0722 {
0723     return blocking_notifier_call_chain(&port->n_head, event, NULL);
0724 }
0725 EXPORT_SYMBOL_GPL(hsi_event);
0726
0727 /**
0728  * hsi_get_channel_id_by_name - acquire channel id by channel name
0729  * @cl: HSI client, which uses the channel
0730  * @name: name the channel is known under
0731  *
0732  * Clients can call this function to get the hsi channel ids similar to
0733  * requesting IRQs or GPIOs by name. This function assumes the same
0734  * channel configuration is used for RX and TX.
0735  *
0736  * Returns -errno on error or channel id on success.
0737  */
0738 int hsi_get_channel_id_by_name(struct hsi_client *cl, char *name)
0739 {
0740     int i;
0741
0742     if (!cl->rx_cfg.channels)
0743         return -ENOENT;
0744
0745     for (i = 0; i < cl->rx_cfg.num_channels; i++)
0746         if (!strcmp(cl->rx_cfg.channels[i].name, name))
0747             return cl->rx_cfg.channels[i].id;
0748
0749     return -ENXIO;
0750 }
0751 EXPORT_SYMBOL_GPL(hsi_get_channel_id_by_name);
0752
0753 static int __init hsi_init(void)
0754 {
0755     return bus_register(&hsi_bus_type);
0756 }
0757 postcore_initcall(hsi_init);
0758
0759 static void __exit hsi_exit(void)
0760 {
0761     bus_unregister(&hsi_bus_type);
0762 }
0763 module_exit(hsi_exit);
0764
0765 MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
0766 MODULE_DESCRIPTION("High-speed Synchronous Serial Interface (HSI) framework");
0767 MODULE_LICENSE("GPL v2");