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authorAndrew F. Davis <afd@ti.com>2016-06-14 11:13:04 -0500
committerSebastian Reichel <sre@kernel.org>2016-06-15 16:02:50 +0200
commite01957abd4cb3816a1eaaf191b16de182ebb333e (patch)
tree17e4e4cdae2b6bcf4d8a6353cc592228147b8f4d /drivers/hsi/hsi_core.c
parent3c13ab1d96e1924ef73b1a20c1ccccc993b6fb58 (diff)
hsi: Build hsi_boardinfo.c into hsi core if enabled
If the HSI core is built as a module hsi_boardinfo may still be built-in as its Kconfig type is bool, which can cause build issues. Fix this by building this code into the HSI core when enabled. Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Andrew F. Davis <afd@ti.com> Signed-off-by: Sebastian Reichel <sre@kernel.org>
Diffstat (limited to 'drivers/hsi/hsi_core.c')
-rw-r--r--drivers/hsi/hsi_core.c781
1 files changed, 781 insertions, 0 deletions
diff --git a/drivers/hsi/hsi_core.c b/drivers/hsi/hsi_core.c
new file mode 100644
index 000000000000..d7ce07ad67f3
--- /dev/null
+++ b/drivers/hsi/hsi_core.c
@@ -0,0 +1,781 @@
+/*
+ * HSI core.
+ *
+ * Copyright (C) 2010 Nokia Corporation. All rights reserved.
+ *
+ * Contact: Carlos Chinea <carlos.chinea@nokia.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+#include <linux/hsi/hsi.h>
+#include <linux/compiler.h>
+#include <linux/list.h>
+#include <linux/kobject.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/notifier.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include "hsi_core.h"
+
+static ssize_t modalias_show(struct device *dev,
+ struct device_attribute *a __maybe_unused, char *buf)
+{
+ return sprintf(buf, "hsi:%s\n", dev_name(dev));
+}
+static DEVICE_ATTR_RO(modalias);
+
+static struct attribute *hsi_bus_dev_attrs[] = {
+ &dev_attr_modalias.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(hsi_bus_dev);
+
+static int hsi_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+ add_uevent_var(env, "MODALIAS=hsi:%s", dev_name(dev));
+
+ return 0;
+}
+
+static int hsi_bus_match(struct device *dev, struct device_driver *driver)
+{
+ if (of_driver_match_device(dev, driver))
+ return true;
+
+ if (strcmp(dev_name(dev), driver->name) == 0)
+ return true;
+
+ return false;
+}
+
+static struct bus_type hsi_bus_type = {
+ .name = "hsi",
+ .dev_groups = hsi_bus_dev_groups,
+ .match = hsi_bus_match,
+ .uevent = hsi_bus_uevent,
+};
+
+static void hsi_client_release(struct device *dev)
+{
+ struct hsi_client *cl = to_hsi_client(dev);
+
+ kfree(cl->tx_cfg.channels);
+ kfree(cl->rx_cfg.channels);
+ kfree(cl);
+}
+
+struct hsi_client *hsi_new_client(struct hsi_port *port,
+ struct hsi_board_info *info)
+{
+ struct hsi_client *cl;
+ size_t size;
+
+ cl = kzalloc(sizeof(*cl), GFP_KERNEL);
+ if (!cl)
+ goto err;
+
+ cl->tx_cfg = info->tx_cfg;
+ if (cl->tx_cfg.channels) {
+ size = cl->tx_cfg.num_channels * sizeof(*cl->tx_cfg.channels);
+ cl->tx_cfg.channels = kmemdup(info->tx_cfg.channels, size,
+ GFP_KERNEL);
+ if (!cl->tx_cfg.channels)
+ goto err_tx;
+ }
+
+ cl->rx_cfg = info->rx_cfg;
+ if (cl->rx_cfg.channels) {
+ size = cl->rx_cfg.num_channels * sizeof(*cl->rx_cfg.channels);
+ cl->rx_cfg.channels = kmemdup(info->rx_cfg.channels, size,
+ GFP_KERNEL);
+ if (!cl->rx_cfg.channels)
+ goto err_rx;
+ }
+
+ cl->device.bus = &hsi_bus_type;
+ cl->device.parent = &port->device;
+ cl->device.release = hsi_client_release;
+ dev_set_name(&cl->device, "%s", info->name);
+ cl->device.platform_data = info->platform_data;
+ if (info->archdata)
+ cl->device.archdata = *info->archdata;
+ if (device_register(&cl->device) < 0) {
+ pr_err("hsi: failed to register client: %s\n", info->name);
+ put_device(&cl->device);
+ }
+
+ return cl;
+err_rx:
+ kfree(cl->tx_cfg.channels);
+err_tx:
+ kfree(cl);
+err:
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(hsi_new_client);
+
+static void hsi_scan_board_info(struct hsi_controller *hsi)
+{
+ struct hsi_cl_info *cl_info;
+ struct hsi_port *p;
+
+ list_for_each_entry(cl_info, &hsi_board_list, list)
+ if (cl_info->info.hsi_id == hsi->id) {
+ p = hsi_find_port_num(hsi, cl_info->info.port);
+ if (!p)
+ continue;
+ hsi_new_client(p, &cl_info->info);
+ }
+}
+
+#ifdef CONFIG_OF
+static struct hsi_board_info hsi_char_dev_info = {
+ .name = "hsi_char",
+};
+
+static int hsi_of_property_parse_mode(struct device_node *client, char *name,
+ unsigned int *result)
+{
+ const char *mode;
+ int err;
+
+ err = of_property_read_string(client, name, &mode);
+ if (err < 0)
+ return err;
+
+ if (strcmp(mode, "stream") == 0)
+ *result = HSI_MODE_STREAM;
+ else if (strcmp(mode, "frame") == 0)
+ *result = HSI_MODE_FRAME;
+ else
+ return -EINVAL;
+
+ return 0;
+}
+
+static int hsi_of_property_parse_flow(struct device_node *client, char *name,
+ unsigned int *result)
+{
+ const char *flow;
+ int err;
+
+ err = of_property_read_string(client, name, &flow);
+ if (err < 0)
+ return err;
+
+ if (strcmp(flow, "synchronized") == 0)
+ *result = HSI_FLOW_SYNC;
+ else if (strcmp(flow, "pipeline") == 0)
+ *result = HSI_FLOW_PIPE;
+ else
+ return -EINVAL;
+
+ return 0;
+}
+
+static int hsi_of_property_parse_arb_mode(struct device_node *client,
+ char *name, unsigned int *result)
+{
+ const char *arb_mode;
+ int err;
+
+ err = of_property_read_string(client, name, &arb_mode);
+ if (err < 0)
+ return err;
+
+ if (strcmp(arb_mode, "round-robin") == 0)
+ *result = HSI_ARB_RR;
+ else if (strcmp(arb_mode, "priority") == 0)
+ *result = HSI_ARB_PRIO;
+ else
+ return -EINVAL;
+
+ return 0;
+}
+
+static void hsi_add_client_from_dt(struct hsi_port *port,
+ struct device_node *client)
+{
+ struct hsi_client *cl;
+ struct hsi_channel channel;
+ struct property *prop;
+ char name[32];
+ int length, cells, err, i, max_chan, mode;
+
+ cl = kzalloc(sizeof(*cl), GFP_KERNEL);
+ if (!cl)
+ return;
+
+ err = of_modalias_node(client, name, sizeof(name));
+ if (err)
+ goto err;
+
+ dev_set_name(&cl->device, "%s", name);
+
+ err = hsi_of_property_parse_mode(client, "hsi-mode", &mode);
+ if (err) {
+ err = hsi_of_property_parse_mode(client, "hsi-rx-mode",
+ &cl->rx_cfg.mode);
+ if (err)
+ goto err;
+
+ err = hsi_of_property_parse_mode(client, "hsi-tx-mode",
+ &cl->tx_cfg.mode);
+ if (err)
+ goto err;
+ } else {
+ cl->rx_cfg.mode = mode;
+ cl->tx_cfg.mode = mode;
+ }
+
+ err = of_property_read_u32(client, "hsi-speed-kbps",
+ &cl->tx_cfg.speed);
+ if (err)
+ goto err;
+ cl->rx_cfg.speed = cl->tx_cfg.speed;
+
+ err = hsi_of_property_parse_flow(client, "hsi-flow",
+ &cl->rx_cfg.flow);
+ if (err)
+ goto err;
+
+ err = hsi_of_property_parse_arb_mode(client, "hsi-arb-mode",
+ &cl->rx_cfg.arb_mode);
+ if (err)
+ goto err;
+
+ prop = of_find_property(client, "hsi-channel-ids", &length);
+ if (!prop) {
+ err = -EINVAL;
+ goto err;
+ }
+
+ cells = length / sizeof(u32);
+
+ cl->rx_cfg.num_channels = cells;
+ cl->tx_cfg.num_channels = cells;
+
+ cl->rx_cfg.channels = kzalloc(cells * sizeof(channel), GFP_KERNEL);
+ if (!cl->rx_cfg.channels) {
+ err = -ENOMEM;
+ goto err;
+ }
+
+ cl->tx_cfg.channels = kzalloc(cells * sizeof(channel), GFP_KERNEL);
+ if (!cl->tx_cfg.channels) {
+ err = -ENOMEM;
+ goto err2;
+ }
+
+ max_chan = 0;
+ for (i = 0; i < cells; i++) {
+ err = of_property_read_u32_index(client, "hsi-channel-ids", i,
+ &channel.id);
+ if (err)
+ goto err3;
+
+ err = of_property_read_string_index(client, "hsi-channel-names",
+ i, &channel.name);
+ if (err)
+ channel.name = NULL;
+
+ if (channel.id > max_chan)
+ max_chan = channel.id;
+
+ cl->rx_cfg.channels[i] = channel;
+ cl->tx_cfg.channels[i] = channel;
+ }
+
+ cl->rx_cfg.num_hw_channels = max_chan + 1;
+ cl->tx_cfg.num_hw_channels = max_chan + 1;
+
+ cl->device.bus = &hsi_bus_type;
+ cl->device.parent = &port->device;
+ cl->device.release = hsi_client_release;
+ cl->device.of_node = client;
+
+ if (device_register(&cl->device) < 0) {
+ pr_err("hsi: failed to register client: %s\n", name);
+ put_device(&cl->device);
+ }
+
+ return;
+
+err3:
+ kfree(cl->tx_cfg.channels);
+err2:
+ kfree(cl->rx_cfg.channels);
+err:
+ kfree(cl);
+ pr_err("hsi client: missing or incorrect of property: err=%d\n", err);
+}
+
+void hsi_add_clients_from_dt(struct hsi_port *port, struct device_node *clients)
+{
+ struct device_node *child;
+
+ /* register hsi-char device */
+ hsi_new_client(port, &hsi_char_dev_info);
+
+ for_each_available_child_of_node(clients, child)
+ hsi_add_client_from_dt(port, child);
+}
+EXPORT_SYMBOL_GPL(hsi_add_clients_from_dt);
+#endif
+
+int hsi_remove_client(struct device *dev, void *data __maybe_unused)
+{
+ device_unregister(dev);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(hsi_remove_client);
+
+static int hsi_remove_port(struct device *dev, void *data __maybe_unused)
+{
+ device_for_each_child(dev, NULL, hsi_remove_client);
+ device_unregister(dev);
+
+ return 0;
+}
+
+static void hsi_controller_release(struct device *dev)
+{
+ struct hsi_controller *hsi = to_hsi_controller(dev);
+
+ kfree(hsi->port);
+ kfree(hsi);
+}
+
+static void hsi_port_release(struct device *dev)
+{
+ kfree(to_hsi_port(dev));
+}
+
+/**
+ * hsi_unregister_port - Unregister an HSI port
+ * @port: The HSI port to unregister
+ */
+void hsi_port_unregister_clients(struct hsi_port *port)
+{
+ device_for_each_child(&port->device, NULL, hsi_remove_client);
+}
+EXPORT_SYMBOL_GPL(hsi_port_unregister_clients);
+
+/**
+ * hsi_unregister_controller - Unregister an HSI controller
+ * @hsi: The HSI controller to register
+ */
+void hsi_unregister_controller(struct hsi_controller *hsi)
+{
+ device_for_each_child(&hsi->device, NULL, hsi_remove_port);
+ device_unregister(&hsi->device);
+}
+EXPORT_SYMBOL_GPL(hsi_unregister_controller);
+
+/**
+ * hsi_register_controller - Register an HSI controller and its ports
+ * @hsi: The HSI controller to register
+ *
+ * Returns -errno on failure, 0 on success.
+ */
+int hsi_register_controller(struct hsi_controller *hsi)
+{
+ unsigned int i;
+ int err;
+
+ err = device_add(&hsi->device);
+ if (err < 0)
+ return err;
+ for (i = 0; i < hsi->num_ports; i++) {
+ hsi->port[i]->device.parent = &hsi->device;
+ err = device_add(&hsi->port[i]->device);
+ if (err < 0)
+ goto out;
+ }
+ /* Populate HSI bus with HSI clients */
+ hsi_scan_board_info(hsi);
+
+ return 0;
+out:
+ while (i-- > 0)
+ device_del(&hsi->port[i]->device);
+ device_del(&hsi->device);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(hsi_register_controller);
+
+/**
+ * hsi_register_client_driver - Register an HSI client to the HSI bus
+ * @drv: HSI client driver to register
+ *
+ * Returns -errno on failure, 0 on success.
+ */
+int hsi_register_client_driver(struct hsi_client_driver *drv)
+{
+ drv->driver.bus = &hsi_bus_type;
+
+ return driver_register(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(hsi_register_client_driver);
+
+static inline int hsi_dummy_msg(struct hsi_msg *msg __maybe_unused)
+{
+ return 0;
+}
+
+static inline int hsi_dummy_cl(struct hsi_client *cl __maybe_unused)
+{
+ return 0;
+}
+
+/**
+ * hsi_put_controller - Free an HSI controller
+ *
+ * @hsi: Pointer to the HSI controller to freed
+ *
+ * HSI controller drivers should only use this function if they need
+ * to free their allocated hsi_controller structures before a successful
+ * call to hsi_register_controller. Other use is not allowed.
+ */
+void hsi_put_controller(struct hsi_controller *hsi)
+{
+ unsigned int i;
+
+ if (!hsi)
+ return;
+
+ for (i = 0; i < hsi->num_ports; i++)
+ if (hsi->port && hsi->port[i])
+ put_device(&hsi->port[i]->device);
+ put_device(&hsi->device);
+}
+EXPORT_SYMBOL_GPL(hsi_put_controller);
+
+/**
+ * hsi_alloc_controller - Allocate an HSI controller and its ports
+ * @n_ports: Number of ports on the HSI controller
+ * @flags: Kernel allocation flags
+ *
+ * Return NULL on failure or a pointer to an hsi_controller on success.
+ */
+struct hsi_controller *hsi_alloc_controller(unsigned int n_ports, gfp_t flags)
+{
+ struct hsi_controller *hsi;
+ struct hsi_port **port;
+ unsigned int i;
+
+ if (!n_ports)
+ return NULL;
+
+ hsi = kzalloc(sizeof(*hsi), flags);
+ if (!hsi)
+ return NULL;
+ port = kzalloc(sizeof(*port)*n_ports, flags);
+ if (!port) {
+ kfree(hsi);
+ return NULL;
+ }
+ hsi->num_ports = n_ports;
+ hsi->port = port;
+ hsi->device.release = hsi_controller_release;
+ device_initialize(&hsi->device);
+
+ for (i = 0; i < n_ports; i++) {
+ port[i] = kzalloc(sizeof(**port), flags);
+ if (port[i] == NULL)
+ goto out;
+ port[i]->num = i;
+ port[i]->async = hsi_dummy_msg;
+ port[i]->setup = hsi_dummy_cl;
+ port[i]->flush = hsi_dummy_cl;
+ port[i]->start_tx = hsi_dummy_cl;
+ port[i]->stop_tx = hsi_dummy_cl;
+ port[i]->release = hsi_dummy_cl;
+ mutex_init(&port[i]->lock);
+ ATOMIC_INIT_NOTIFIER_HEAD(&port[i]->n_head);
+ dev_set_name(&port[i]->device, "port%d", i);
+ hsi->port[i]->device.release = hsi_port_release;
+ device_initialize(&hsi->port[i]->device);
+ }
+
+ return hsi;
+out:
+ hsi_put_controller(hsi);
+
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(hsi_alloc_controller);
+
+/**
+ * hsi_free_msg - Free an HSI message
+ * @msg: Pointer to the HSI message
+ *
+ * Client is responsible to free the buffers pointed by the scatterlists.
+ */
+void hsi_free_msg(struct hsi_msg *msg)
+{
+ if (!msg)
+ return;
+ sg_free_table(&msg->sgt);
+ kfree(msg);
+}
+EXPORT_SYMBOL_GPL(hsi_free_msg);
+
+/**
+ * hsi_alloc_msg - Allocate an HSI message
+ * @nents: Number of memory entries
+ * @flags: Kernel allocation flags
+ *
+ * nents can be 0. This mainly makes sense for read transfer.
+ * In that case, HSI drivers will call the complete callback when
+ * there is data to be read without consuming it.
+ *
+ * Return NULL on failure or a pointer to an hsi_msg on success.
+ */
+struct hsi_msg *hsi_alloc_msg(unsigned int nents, gfp_t flags)
+{
+ struct hsi_msg *msg;
+ int err;
+
+ msg = kzalloc(sizeof(*msg), flags);
+ if (!msg)
+ return NULL;
+
+ if (!nents)
+ return msg;
+
+ err = sg_alloc_table(&msg->sgt, nents, flags);
+ if (unlikely(err)) {
+ kfree(msg);
+ msg = NULL;
+ }
+
+ return msg;
+}
+EXPORT_SYMBOL_GPL(hsi_alloc_msg);
+
+/**
+ * hsi_async - Submit an HSI transfer to the controller
+ * @cl: HSI client sending the transfer
+ * @msg: The HSI transfer passed to controller
+ *
+ * The HSI message must have the channel, ttype, complete and destructor
+ * fields set beforehand. If nents > 0 then the client has to initialize
+ * also the scatterlists to point to the buffers to write to or read from.
+ *
+ * HSI controllers relay on pre-allocated buffers from their clients and they
+ * do not allocate buffers on their own.
+ *
+ * Once the HSI message transfer finishes, the HSI controller calls the
+ * complete callback with the status and actual_len fields of the HSI message
+ * updated. The complete callback can be called before returning from
+ * hsi_async.
+ *
+ * Returns -errno on failure or 0 on success
+ */
+int hsi_async(struct hsi_client *cl, struct hsi_msg *msg)
+{
+ struct hsi_port *port = hsi_get_port(cl);
+
+ if (!hsi_port_claimed(cl))
+ return -EACCES;
+
+ WARN_ON_ONCE(!msg->destructor || !msg->complete);
+ msg->cl = cl;
+
+ return port->async(msg);
+}
+EXPORT_SYMBOL_GPL(hsi_async);
+
+/**
+ * hsi_claim_port - Claim the HSI client's port
+ * @cl: HSI client that wants to claim its port
+ * @share: Flag to indicate if the client wants to share the port or not.
+ *
+ * Returns -errno on failure, 0 on success.
+ */
+int hsi_claim_port(struct hsi_client *cl, unsigned int share)
+{
+ struct hsi_port *port = hsi_get_port(cl);
+ int err = 0;
+
+ mutex_lock(&port->lock);
+ if ((port->claimed) && (!port->shared || !share)) {
+ err = -EBUSY;
+ goto out;
+ }
+ if (!try_module_get(to_hsi_controller(port->device.parent)->owner)) {
+ err = -ENODEV;
+ goto out;
+ }
+ port->claimed++;
+ port->shared = !!share;
+ cl->pclaimed = 1;
+out:
+ mutex_unlock(&port->lock);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(hsi_claim_port);
+
+/**
+ * hsi_release_port - Release the HSI client's port
+ * @cl: HSI client which previously claimed its port
+ */
+void hsi_release_port(struct hsi_client *cl)
+{
+ struct hsi_port *port = hsi_get_port(cl);
+
+ mutex_lock(&port->lock);
+ /* Allow HW driver to do some cleanup */
+ port->release(cl);
+ if (cl->pclaimed)
+ port->claimed--;
+ BUG_ON(port->claimed < 0);
+ cl->pclaimed = 0;
+ if (!port->claimed)
+ port->shared = 0;
+ module_put(to_hsi_controller(port->device.parent)->owner);
+ mutex_unlock(&port->lock);
+}
+EXPORT_SYMBOL_GPL(hsi_release_port);
+
+static int hsi_event_notifier_call(struct notifier_block *nb,
+ unsigned long event, void *data __maybe_unused)
+{
+ struct hsi_client *cl = container_of(nb, struct hsi_client, nb);
+
+ (*cl->ehandler)(cl, event);
+
+ return 0;
+}
+
+/**
+ * hsi_register_port_event - Register a client to receive port events
+ * @cl: HSI client that wants to receive port events
+ * @handler: Event handler callback
+ *
+ * Clients should register a callback to be able to receive
+ * events from the ports. Registration should happen after
+ * claiming the port.
+ * The handler can be called in interrupt context.
+ *
+ * Returns -errno on error, or 0 on success.
+ */
+int hsi_register_port_event(struct hsi_client *cl,
+ void (*handler)(struct hsi_client *, unsigned long))
+{
+ struct hsi_port *port = hsi_get_port(cl);
+
+ if (!handler || cl->ehandler)
+ return -EINVAL;
+ if (!hsi_port_claimed(cl))
+ return -EACCES;
+ cl->ehandler = handler;
+ cl->nb.notifier_call = hsi_event_notifier_call;
+
+ return atomic_notifier_chain_register(&port->n_head, &cl->nb);
+}
+EXPORT_SYMBOL_GPL(hsi_register_port_event);
+
+/**
+ * hsi_unregister_port_event - Stop receiving port events for a client
+ * @cl: HSI client that wants to stop receiving port events
+ *
+ * Clients should call this function before releasing their associated
+ * port.
+ *
+ * Returns -errno on error, or 0 on success.
+ */
+int hsi_unregister_port_event(struct hsi_client *cl)
+{
+ struct hsi_port *port = hsi_get_port(cl);
+ int err;
+
+ WARN_ON(!hsi_port_claimed(cl));
+
+ err = atomic_notifier_chain_unregister(&port->n_head, &cl->nb);
+ if (!err)
+ cl->ehandler = NULL;
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(hsi_unregister_port_event);
+
+/**
+ * hsi_event - Notifies clients about port events
+ * @port: Port where the event occurred
+ * @event: The event type
+ *
+ * Clients should not be concerned about wake line behavior. However, due
+ * to a race condition in HSI HW protocol, clients need to be notified
+ * about wake line changes, so they can implement a workaround for it.
+ *
+ * Events:
+ * HSI_EVENT_START_RX - Incoming wake line high
+ * HSI_EVENT_STOP_RX - Incoming wake line down
+ *
+ * Returns -errno on error, or 0 on success.
+ */
+int hsi_event(struct hsi_port *port, unsigned long event)
+{
+ return atomic_notifier_call_chain(&port->n_head, event, NULL);
+}
+EXPORT_SYMBOL_GPL(hsi_event);
+
+/**
+ * hsi_get_channel_id_by_name - acquire channel id by channel name
+ * @cl: HSI client, which uses the channel
+ * @name: name the channel is known under
+ *
+ * Clients can call this function to get the hsi channel ids similar to
+ * requesting IRQs or GPIOs by name. This function assumes the same
+ * channel configuration is used for RX and TX.
+ *
+ * Returns -errno on error or channel id on success.
+ */
+int hsi_get_channel_id_by_name(struct hsi_client *cl, char *name)
+{
+ int i;
+
+ if (!cl->rx_cfg.channels)
+ return -ENOENT;
+
+ for (i = 0; i < cl->rx_cfg.num_channels; i++)
+ if (!strcmp(cl->rx_cfg.channels[i].name, name))
+ return cl->rx_cfg.channels[i].id;
+
+ return -ENXIO;
+}
+EXPORT_SYMBOL_GPL(hsi_get_channel_id_by_name);
+
+static int __init hsi_init(void)
+{
+ return bus_register(&hsi_bus_type);
+}
+postcore_initcall(hsi_init);
+
+static void __exit hsi_exit(void)
+{
+ bus_unregister(&hsi_bus_type);
+}
+module_exit(hsi_exit);
+
+MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
+MODULE_DESCRIPTION("High-speed Synchronous Serial Interface (HSI) framework");
+MODULE_LICENSE("GPL v2");

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