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Diffstat (limited to 'drivers/input/gameport/gameport.c')
-rw-r--r--drivers/input/gameport/gameport.c855
1 files changed, 855 insertions, 0 deletions
diff --git a/drivers/input/gameport/gameport.c b/drivers/input/gameport/gameport.c
new file mode 100644
index 000000000..db58a01b2
--- /dev/null
+++ b/drivers/input/gameport/gameport.c
@@ -0,0 +1,855 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Generic gameport layer
+ *
+ * Copyright (c) 1999-2002 Vojtech Pavlik
+ * Copyright (c) 2005 Dmitry Torokhov
+ */
+
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/stddef.h>
+#include <linux/module.h>
+#include <linux/ioport.h>
+#include <linux/init.h>
+#include <linux/gameport.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/workqueue.h>
+#include <linux/sched.h> /* HZ */
+#include <linux/mutex.h>
+#include <linux/timekeeping.h>
+
+/*#include <asm/io.h>*/
+
+MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
+MODULE_DESCRIPTION("Generic gameport layer");
+MODULE_LICENSE("GPL");
+
+static bool use_ktime = true;
+module_param(use_ktime, bool, 0400);
+MODULE_PARM_DESC(use_ktime, "Use ktime for measuring I/O speed");
+
+/*
+ * gameport_mutex protects entire gameport subsystem and is taken
+ * every time gameport port or driver registrered or unregistered.
+ */
+static DEFINE_MUTEX(gameport_mutex);
+
+static LIST_HEAD(gameport_list);
+
+static struct bus_type gameport_bus;
+
+static void gameport_add_port(struct gameport *gameport);
+static void gameport_attach_driver(struct gameport_driver *drv);
+static void gameport_reconnect_port(struct gameport *gameport);
+static void gameport_disconnect_port(struct gameport *gameport);
+
+#if defined(__i386__)
+
+#include <linux/i8253.h>
+
+#define DELTA(x,y) ((y)-(x)+((y)<(x)?1193182/HZ:0))
+#define GET_TIME(x) do { x = get_time_pit(); } while (0)
+
+static unsigned int get_time_pit(void)
+{
+ unsigned long flags;
+ unsigned int count;
+
+ raw_spin_lock_irqsave(&i8253_lock, flags);
+ outb_p(0x00, 0x43);
+ count = inb_p(0x40);
+ count |= inb_p(0x40) << 8;
+ raw_spin_unlock_irqrestore(&i8253_lock, flags);
+
+ return count;
+}
+
+#endif
+
+
+
+/*
+ * gameport_measure_speed() measures the gameport i/o speed.
+ */
+
+static int gameport_measure_speed(struct gameport *gameport)
+{
+ unsigned int i, t, tx;
+ u64 t1, t2, t3;
+ unsigned long flags;
+
+ if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
+ return 0;
+
+ tx = ~0;
+
+ for (i = 0; i < 50; i++) {
+ local_irq_save(flags);
+ t1 = ktime_get_ns();
+ for (t = 0; t < 50; t++)
+ gameport_read(gameport);
+ t2 = ktime_get_ns();
+ t3 = ktime_get_ns();
+ local_irq_restore(flags);
+ udelay(i * 10);
+ t = (t2 - t1) - (t3 - t2);
+ if (t < tx)
+ tx = t;
+ }
+
+ gameport_close(gameport);
+ t = 1000000 * 50;
+ if (tx)
+ t /= tx;
+ return t;
+}
+
+static int old_gameport_measure_speed(struct gameport *gameport)
+{
+#if defined(__i386__)
+
+ unsigned int i, t, t1, t2, t3, tx;
+ unsigned long flags;
+
+ if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
+ return 0;
+
+ tx = 1 << 30;
+
+ for(i = 0; i < 50; i++) {
+ local_irq_save(flags);
+ GET_TIME(t1);
+ for (t = 0; t < 50; t++) gameport_read(gameport);
+ GET_TIME(t2);
+ GET_TIME(t3);
+ local_irq_restore(flags);
+ udelay(i * 10);
+ if ((t = DELTA(t2,t1) - DELTA(t3,t2)) < tx) tx = t;
+ }
+
+ gameport_close(gameport);
+ return 59659 / (tx < 1 ? 1 : tx);
+
+#elif defined (__x86_64__)
+
+ unsigned int i, t;
+ unsigned long tx, t1, t2, flags;
+
+ if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
+ return 0;
+
+ tx = 1 << 30;
+
+ for(i = 0; i < 50; i++) {
+ local_irq_save(flags);
+ t1 = rdtsc();
+ for (t = 0; t < 50; t++) gameport_read(gameport);
+ t2 = rdtsc();
+ local_irq_restore(flags);
+ udelay(i * 10);
+ if (t2 - t1 < tx) tx = t2 - t1;
+ }
+
+ gameport_close(gameport);
+ return (this_cpu_read(cpu_info.loops_per_jiffy) *
+ (unsigned long)HZ / (1000 / 50)) / (tx < 1 ? 1 : tx);
+
+#else
+
+ unsigned int j, t = 0;
+
+ if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
+ return 0;
+
+ j = jiffies; while (j == jiffies);
+ j = jiffies; while (j == jiffies) { t++; gameport_read(gameport); }
+
+ gameport_close(gameport);
+ return t * HZ / 1000;
+
+#endif
+}
+
+void gameport_start_polling(struct gameport *gameport)
+{
+ spin_lock(&gameport->timer_lock);
+
+ if (!gameport->poll_cnt++) {
+ BUG_ON(!gameport->poll_handler);
+ BUG_ON(!gameport->poll_interval);
+ mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
+ }
+
+ spin_unlock(&gameport->timer_lock);
+}
+EXPORT_SYMBOL(gameport_start_polling);
+
+void gameport_stop_polling(struct gameport *gameport)
+{
+ spin_lock(&gameport->timer_lock);
+
+ if (!--gameport->poll_cnt)
+ del_timer(&gameport->poll_timer);
+
+ spin_unlock(&gameport->timer_lock);
+}
+EXPORT_SYMBOL(gameport_stop_polling);
+
+static void gameport_run_poll_handler(struct timer_list *t)
+{
+ struct gameport *gameport = from_timer(gameport, t, poll_timer);
+
+ gameport->poll_handler(gameport);
+ if (gameport->poll_cnt)
+ mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
+}
+
+/*
+ * Basic gameport -> driver core mappings
+ */
+
+static int gameport_bind_driver(struct gameport *gameport, struct gameport_driver *drv)
+{
+ int error;
+
+ gameport->dev.driver = &drv->driver;
+ if (drv->connect(gameport, drv)) {
+ gameport->dev.driver = NULL;
+ return -ENODEV;
+ }
+
+ error = device_bind_driver(&gameport->dev);
+ if (error) {
+ dev_warn(&gameport->dev,
+ "device_bind_driver() failed for %s (%s) and %s, error: %d\n",
+ gameport->phys, gameport->name,
+ drv->description, error);
+ drv->disconnect(gameport);
+ gameport->dev.driver = NULL;
+ return error;
+ }
+
+ return 0;
+}
+
+static void gameport_find_driver(struct gameport *gameport)
+{
+ int error;
+
+ error = device_attach(&gameport->dev);
+ if (error < 0)
+ dev_warn(&gameport->dev,
+ "device_attach() failed for %s (%s), error: %d\n",
+ gameport->phys, gameport->name, error);
+}
+
+
+/*
+ * Gameport event processing.
+ */
+
+enum gameport_event_type {
+ GAMEPORT_REGISTER_PORT,
+ GAMEPORT_ATTACH_DRIVER,
+};
+
+struct gameport_event {
+ enum gameport_event_type type;
+ void *object;
+ struct module *owner;
+ struct list_head node;
+};
+
+static DEFINE_SPINLOCK(gameport_event_lock); /* protects gameport_event_list */
+static LIST_HEAD(gameport_event_list);
+
+static struct gameport_event *gameport_get_event(void)
+{
+ struct gameport_event *event = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&gameport_event_lock, flags);
+
+ if (!list_empty(&gameport_event_list)) {
+ event = list_first_entry(&gameport_event_list,
+ struct gameport_event, node);
+ list_del_init(&event->node);
+ }
+
+ spin_unlock_irqrestore(&gameport_event_lock, flags);
+ return event;
+}
+
+static void gameport_free_event(struct gameport_event *event)
+{
+ module_put(event->owner);
+ kfree(event);
+}
+
+static void gameport_remove_duplicate_events(struct gameport_event *event)
+{
+ struct gameport_event *e, *next;
+ unsigned long flags;
+
+ spin_lock_irqsave(&gameport_event_lock, flags);
+
+ list_for_each_entry_safe(e, next, &gameport_event_list, node) {
+ if (event->object == e->object) {
+ /*
+ * If this event is of different type we should not
+ * look further - we only suppress duplicate events
+ * that were sent back-to-back.
+ */
+ if (event->type != e->type)
+ break;
+
+ list_del_init(&e->node);
+ gameport_free_event(e);
+ }
+ }
+
+ spin_unlock_irqrestore(&gameport_event_lock, flags);
+}
+
+
+static void gameport_handle_events(struct work_struct *work)
+{
+ struct gameport_event *event;
+
+ mutex_lock(&gameport_mutex);
+
+ /*
+ * Note that we handle only one event here to give swsusp
+ * a chance to freeze kgameportd thread. Gameport events
+ * should be pretty rare so we are not concerned about
+ * taking performance hit.
+ */
+ if ((event = gameport_get_event())) {
+
+ switch (event->type) {
+
+ case GAMEPORT_REGISTER_PORT:
+ gameport_add_port(event->object);
+ break;
+
+ case GAMEPORT_ATTACH_DRIVER:
+ gameport_attach_driver(event->object);
+ break;
+ }
+
+ gameport_remove_duplicate_events(event);
+ gameport_free_event(event);
+ }
+
+ mutex_unlock(&gameport_mutex);
+}
+
+static DECLARE_WORK(gameport_event_work, gameport_handle_events);
+
+static int gameport_queue_event(void *object, struct module *owner,
+ enum gameport_event_type event_type)
+{
+ unsigned long flags;
+ struct gameport_event *event;
+ int retval = 0;
+
+ spin_lock_irqsave(&gameport_event_lock, flags);
+
+ /*
+ * Scan event list for the other events for the same gameport port,
+ * starting with the most recent one. If event is the same we
+ * do not need add new one. If event is of different type we
+ * need to add this event and should not look further because
+ * we need to preserve sequence of distinct events.
+ */
+ list_for_each_entry_reverse(event, &gameport_event_list, node) {
+ if (event->object == object) {
+ if (event->type == event_type)
+ goto out;
+ break;
+ }
+ }
+
+ event = kmalloc(sizeof(struct gameport_event), GFP_ATOMIC);
+ if (!event) {
+ pr_err("Not enough memory to queue event %d\n", event_type);
+ retval = -ENOMEM;
+ goto out;
+ }
+
+ if (!try_module_get(owner)) {
+ pr_warn("Can't get module reference, dropping event %d\n",
+ event_type);
+ kfree(event);
+ retval = -EINVAL;
+ goto out;
+ }
+
+ event->type = event_type;
+ event->object = object;
+ event->owner = owner;
+
+ list_add_tail(&event->node, &gameport_event_list);
+ queue_work(system_long_wq, &gameport_event_work);
+
+out:
+ spin_unlock_irqrestore(&gameport_event_lock, flags);
+ return retval;
+}
+
+/*
+ * Remove all events that have been submitted for a given object,
+ * be it a gameport port or a driver.
+ */
+static void gameport_remove_pending_events(void *object)
+{
+ struct gameport_event *event, *next;
+ unsigned long flags;
+
+ spin_lock_irqsave(&gameport_event_lock, flags);
+
+ list_for_each_entry_safe(event, next, &gameport_event_list, node) {
+ if (event->object == object) {
+ list_del_init(&event->node);
+ gameport_free_event(event);
+ }
+ }
+
+ spin_unlock_irqrestore(&gameport_event_lock, flags);
+}
+
+/*
+ * Destroy child gameport port (if any) that has not been fully registered yet.
+ *
+ * Note that we rely on the fact that port can have only one child and therefore
+ * only one child registration request can be pending. Additionally, children
+ * are registered by driver's connect() handler so there can't be a grandchild
+ * pending registration together with a child.
+ */
+static struct gameport *gameport_get_pending_child(struct gameport *parent)
+{
+ struct gameport_event *event;
+ struct gameport *gameport, *child = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&gameport_event_lock, flags);
+
+ list_for_each_entry(event, &gameport_event_list, node) {
+ if (event->type == GAMEPORT_REGISTER_PORT) {
+ gameport = event->object;
+ if (gameport->parent == parent) {
+ child = gameport;
+ break;
+ }
+ }
+ }
+
+ spin_unlock_irqrestore(&gameport_event_lock, flags);
+ return child;
+}
+
+/*
+ * Gameport port operations
+ */
+
+static ssize_t gameport_description_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct gameport *gameport = to_gameport_port(dev);
+
+ return sprintf(buf, "%s\n", gameport->name);
+}
+static DEVICE_ATTR(description, S_IRUGO, gameport_description_show, NULL);
+
+static ssize_t drvctl_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
+{
+ struct gameport *gameport = to_gameport_port(dev);
+ struct device_driver *drv;
+ int error;
+
+ error = mutex_lock_interruptible(&gameport_mutex);
+ if (error)
+ return error;
+
+ if (!strncmp(buf, "none", count)) {
+ gameport_disconnect_port(gameport);
+ } else if (!strncmp(buf, "reconnect", count)) {
+ gameport_reconnect_port(gameport);
+ } else if (!strncmp(buf, "rescan", count)) {
+ gameport_disconnect_port(gameport);
+ gameport_find_driver(gameport);
+ } else if ((drv = driver_find(buf, &gameport_bus)) != NULL) {
+ gameport_disconnect_port(gameport);
+ error = gameport_bind_driver(gameport, to_gameport_driver(drv));
+ } else {
+ error = -EINVAL;
+ }
+
+ mutex_unlock(&gameport_mutex);
+
+ return error ? error : count;
+}
+static DEVICE_ATTR_WO(drvctl);
+
+static struct attribute *gameport_device_attrs[] = {
+ &dev_attr_description.attr,
+ &dev_attr_drvctl.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(gameport_device);
+
+static void gameport_release_port(struct device *dev)
+{
+ struct gameport *gameport = to_gameport_port(dev);
+
+ kfree(gameport);
+ module_put(THIS_MODULE);
+}
+
+void gameport_set_phys(struct gameport *gameport, const char *fmt, ...)
+{
+ va_list args;
+
+ va_start(args, fmt);
+ vsnprintf(gameport->phys, sizeof(gameport->phys), fmt, args);
+ va_end(args);
+}
+EXPORT_SYMBOL(gameport_set_phys);
+
+/*
+ * Prepare gameport port for registration.
+ */
+static void gameport_init_port(struct gameport *gameport)
+{
+ static atomic_t gameport_no = ATOMIC_INIT(-1);
+
+ __module_get(THIS_MODULE);
+
+ mutex_init(&gameport->drv_mutex);
+ device_initialize(&gameport->dev);
+ dev_set_name(&gameport->dev, "gameport%lu",
+ (unsigned long)atomic_inc_return(&gameport_no));
+ gameport->dev.bus = &gameport_bus;
+ gameport->dev.release = gameport_release_port;
+ if (gameport->parent)
+ gameport->dev.parent = &gameport->parent->dev;
+
+ INIT_LIST_HEAD(&gameport->node);
+ spin_lock_init(&gameport->timer_lock);
+ timer_setup(&gameport->poll_timer, gameport_run_poll_handler, 0);
+}
+
+/*
+ * Complete gameport port registration.
+ * Driver core will attempt to find appropriate driver for the port.
+ */
+static void gameport_add_port(struct gameport *gameport)
+{
+ int error;
+
+ if (gameport->parent)
+ gameport->parent->child = gameport;
+
+ gameport->speed = use_ktime ?
+ gameport_measure_speed(gameport) :
+ old_gameport_measure_speed(gameport);
+
+ list_add_tail(&gameport->node, &gameport_list);
+
+ if (gameport->io)
+ dev_info(&gameport->dev, "%s is %s, io %#x, speed %dkHz\n",
+ gameport->name, gameport->phys, gameport->io, gameport->speed);
+ else
+ dev_info(&gameport->dev, "%s is %s, speed %dkHz\n",
+ gameport->name, gameport->phys, gameport->speed);
+
+ error = device_add(&gameport->dev);
+ if (error)
+ dev_err(&gameport->dev,
+ "device_add() failed for %s (%s), error: %d\n",
+ gameport->phys, gameport->name, error);
+}
+
+/*
+ * gameport_destroy_port() completes deregistration process and removes
+ * port from the system
+ */
+static void gameport_destroy_port(struct gameport *gameport)
+{
+ struct gameport *child;
+
+ child = gameport_get_pending_child(gameport);
+ if (child) {
+ gameport_remove_pending_events(child);
+ put_device(&child->dev);
+ }
+
+ if (gameport->parent) {
+ gameport->parent->child = NULL;
+ gameport->parent = NULL;
+ }
+
+ if (device_is_registered(&gameport->dev))
+ device_del(&gameport->dev);
+
+ list_del_init(&gameport->node);
+
+ gameport_remove_pending_events(gameport);
+ put_device(&gameport->dev);
+}
+
+/*
+ * Reconnect gameport port and all its children (re-initialize attached devices)
+ */
+static void gameport_reconnect_port(struct gameport *gameport)
+{
+ do {
+ if (!gameport->drv || !gameport->drv->reconnect || gameport->drv->reconnect(gameport)) {
+ gameport_disconnect_port(gameport);
+ gameport_find_driver(gameport);
+ /* Ok, old children are now gone, we are done */
+ break;
+ }
+ gameport = gameport->child;
+ } while (gameport);
+}
+
+/*
+ * gameport_disconnect_port() unbinds a port from its driver. As a side effect
+ * all child ports are unbound and destroyed.
+ */
+static void gameport_disconnect_port(struct gameport *gameport)
+{
+ struct gameport *s, *parent;
+
+ if (gameport->child) {
+ /*
+ * Children ports should be disconnected and destroyed
+ * first, staring with the leaf one, since we don't want
+ * to do recursion
+ */
+ for (s = gameport; s->child; s = s->child)
+ /* empty */;
+
+ do {
+ parent = s->parent;
+
+ device_release_driver(&s->dev);
+ gameport_destroy_port(s);
+ } while ((s = parent) != gameport);
+ }
+
+ /*
+ * Ok, no children left, now disconnect this port
+ */
+ device_release_driver(&gameport->dev);
+}
+
+/*
+ * Submits register request to kgameportd for subsequent execution.
+ * Note that port registration is always asynchronous.
+ */
+void __gameport_register_port(struct gameport *gameport, struct module *owner)
+{
+ gameport_init_port(gameport);
+ gameport_queue_event(gameport, owner, GAMEPORT_REGISTER_PORT);
+}
+EXPORT_SYMBOL(__gameport_register_port);
+
+/*
+ * Synchronously unregisters gameport port.
+ */
+void gameport_unregister_port(struct gameport *gameport)
+{
+ mutex_lock(&gameport_mutex);
+ gameport_disconnect_port(gameport);
+ gameport_destroy_port(gameport);
+ mutex_unlock(&gameport_mutex);
+}
+EXPORT_SYMBOL(gameport_unregister_port);
+
+
+/*
+ * Gameport driver operations
+ */
+
+static ssize_t description_show(struct device_driver *drv, char *buf)
+{
+ struct gameport_driver *driver = to_gameport_driver(drv);
+ return sprintf(buf, "%s\n", driver->description ? driver->description : "(none)");
+}
+static DRIVER_ATTR_RO(description);
+
+static struct attribute *gameport_driver_attrs[] = {
+ &driver_attr_description.attr,
+ NULL
+};
+ATTRIBUTE_GROUPS(gameport_driver);
+
+static int gameport_driver_probe(struct device *dev)
+{
+ struct gameport *gameport = to_gameport_port(dev);
+ struct gameport_driver *drv = to_gameport_driver(dev->driver);
+
+ drv->connect(gameport, drv);
+ return gameport->drv ? 0 : -ENODEV;
+}
+
+static void gameport_driver_remove(struct device *dev)
+{
+ struct gameport *gameport = to_gameport_port(dev);
+ struct gameport_driver *drv = to_gameport_driver(dev->driver);
+
+ drv->disconnect(gameport);
+}
+
+static void gameport_attach_driver(struct gameport_driver *drv)
+{
+ int error;
+
+ error = driver_attach(&drv->driver);
+ if (error)
+ pr_err("driver_attach() failed for %s, error: %d\n",
+ drv->driver.name, error);
+}
+
+int __gameport_register_driver(struct gameport_driver *drv, struct module *owner,
+ const char *mod_name)
+{
+ int error;
+
+ drv->driver.bus = &gameport_bus;
+ drv->driver.owner = owner;
+ drv->driver.mod_name = mod_name;
+
+ /*
+ * Temporarily disable automatic binding because probing
+ * takes long time and we are better off doing it in kgameportd
+ */
+ drv->ignore = true;
+
+ error = driver_register(&drv->driver);
+ if (error) {
+ pr_err("driver_register() failed for %s, error: %d\n",
+ drv->driver.name, error);
+ return error;
+ }
+
+ /*
+ * Reset ignore flag and let kgameportd bind the driver to free ports
+ */
+ drv->ignore = false;
+ error = gameport_queue_event(drv, NULL, GAMEPORT_ATTACH_DRIVER);
+ if (error) {
+ driver_unregister(&drv->driver);
+ return error;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(__gameport_register_driver);
+
+void gameport_unregister_driver(struct gameport_driver *drv)
+{
+ struct gameport *gameport;
+
+ mutex_lock(&gameport_mutex);
+
+ drv->ignore = true; /* so gameport_find_driver ignores it */
+ gameport_remove_pending_events(drv);
+
+start_over:
+ list_for_each_entry(gameport, &gameport_list, node) {
+ if (gameport->drv == drv) {
+ gameport_disconnect_port(gameport);
+ gameport_find_driver(gameport);
+ /* we could've deleted some ports, restart */
+ goto start_over;
+ }
+ }
+
+ driver_unregister(&drv->driver);
+
+ mutex_unlock(&gameport_mutex);
+}
+EXPORT_SYMBOL(gameport_unregister_driver);
+
+static int gameport_bus_match(struct device *dev, struct device_driver *drv)
+{
+ struct gameport_driver *gameport_drv = to_gameport_driver(drv);
+
+ return !gameport_drv->ignore;
+}
+
+static struct bus_type gameport_bus = {
+ .name = "gameport",
+ .dev_groups = gameport_device_groups,
+ .drv_groups = gameport_driver_groups,
+ .match = gameport_bus_match,
+ .probe = gameport_driver_probe,
+ .remove = gameport_driver_remove,
+};
+
+static void gameport_set_drv(struct gameport *gameport, struct gameport_driver *drv)
+{
+ mutex_lock(&gameport->drv_mutex);
+ gameport->drv = drv;
+ mutex_unlock(&gameport->drv_mutex);
+}
+
+int gameport_open(struct gameport *gameport, struct gameport_driver *drv, int mode)
+{
+ if (gameport->open) {
+ if (gameport->open(gameport, mode)) {
+ return -1;
+ }
+ } else {
+ if (mode != GAMEPORT_MODE_RAW)
+ return -1;
+ }
+
+ gameport_set_drv(gameport, drv);
+ return 0;
+}
+EXPORT_SYMBOL(gameport_open);
+
+void gameport_close(struct gameport *gameport)
+{
+ del_timer_sync(&gameport->poll_timer);
+ gameport->poll_handler = NULL;
+ gameport->poll_interval = 0;
+ gameport_set_drv(gameport, NULL);
+ if (gameport->close)
+ gameport->close(gameport);
+}
+EXPORT_SYMBOL(gameport_close);
+
+static int __init gameport_init(void)
+{
+ int error;
+
+ error = bus_register(&gameport_bus);
+ if (error) {
+ pr_err("failed to register gameport bus, error: %d\n", error);
+ return error;
+ }
+
+
+ return 0;
+}
+
+static void __exit gameport_exit(void)
+{
+ bus_unregister(&gameport_bus);
+
+ /*
+ * There should not be any outstanding events but work may
+ * still be scheduled so simply cancel it.
+ */
+ cancel_work_sync(&gameport_event_work);
+}
+
+subsys_initcall(gameport_init);
+module_exit(gameport_exit);