Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 860 insertions, 0 deletions

diff --git a/drivers/input/gameport/gameport.c b/drivers/input/gameport/gameport.c
new file mode 100644
index 000000000..73862a836
--- /dev/null
+++ b/drivers/input/gameport/gameport.c
@@ -0,0 +1,860 @@
+/*
+ * Generic gameport layer
+ *
+ * Copyright (c) 1999-2002 Vojtech Pavlik
+ * Copyright (c) 2005 Dmitry Torokhov
+ */
+
+/*
+ * 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.
+ */
+
+#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 int 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);
+	return 0;
+}
+
+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);