/*
   * Joystick device driver for the input driver suite.
   *
   * Copyright (c) 1999-2002 Vojtech Pavlik
   * Copyright (c) 1999 Colin Van Dyke
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   */

  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

  #include <asm/io.h>
  #include <asm/system.h>
  #include <linux/delay.h>
  #include <linux/errno.h>
  #include <linux/joystick.h>
  #include <linux/input.h>
  #include <linux/kernel.h>
  #include <linux/major.h>

  #include <linux/sched.h>

  #include <linux/slab.h>
  #include <linux/mm.h>
  #include <linux/miscdevice.h>
  #include <linux/module.h>
  #include <linux/poll.h>
  #include <linux/init.h>

  #include <linux/device.h>

  
  MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
  MODULE_DESCRIPTION("Joystick device interfaces");
  MODULE_SUPPORTED_DEVICE("input/js");
  MODULE_LICENSE("GPL");
  
  #define JOYDEV_MINOR_BASE	0
  #define JOYDEV_MINORS		16
  #define JOYDEV_BUFFER_SIZE	64

  struct joydev {

  	int open;
  	int minor;

  	struct input_handle handle;
  	wait_queue_head_t wait;

  	struct list_head client_list;

  	spinlock_t client_lock; /* protects client_list */
  	struct mutex mutex;

  	struct device dev;

  	bool exist;

  	struct js_corr corr[ABS_CNT];

  	struct JS_DATA_SAVE_TYPE glue;
  	int nabs;
  	int nkey;
  	__u16 keymap[KEY_MAX - BTN_MISC + 1];
  	__u16 keypam[KEY_MAX - BTN_MISC + 1];

  	__u8 absmap[ABS_CNT];
  	__u8 abspam[ABS_CNT];
  	__s16 abs[ABS_CNT];

  };

  struct joydev_client {

  	struct js_event buffer[JOYDEV_BUFFER_SIZE];
  	int head;
  	int tail;
  	int startup;

  	spinlock_t buffer_lock; /* protects access to buffer, head and tail */

  	struct fasync_struct *fasync;
  	struct joydev *joydev;
  	struct list_head node;
  };
  
  static struct joydev *joydev_table[JOYDEV_MINORS];

  static DEFINE_MUTEX(joydev_table_mutex);

  
  static int joydev_correct(int value, struct js_corr *corr)
  {
  	switch (corr->type) {

  
  	case JS_CORR_NONE:
  		break;
  
  	case JS_CORR_BROKEN:
  		value = value > corr->coef[0] ? (value < corr->coef[1] ? 0 :
  			((corr->coef[3] * (value - corr->coef[1])) >> 14)) :
  			((corr->coef[2] * (value - corr->coef[0])) >> 14);
  		break;
  
  	default:
  		return 0;

  	}

  	return value < -32767 ? -32767 : (value > 32767 ? 32767 : value);

  }

  static void joydev_pass_event(struct joydev_client *client,
  			      struct js_event *event)
  {
  	struct joydev *joydev = client->joydev;
  
  	/*
  	 * IRQs already disabled, just acquire the lock
  	 */
  	spin_lock(&client->buffer_lock);
  
  	client->buffer[client->head] = *event;
  
  	if (client->startup == joydev->nabs + joydev->nkey) {
  		client->head++;
  		client->head &= JOYDEV_BUFFER_SIZE - 1;
  		if (client->tail == client->head)
  			client->startup = 0;
  	}
  
  	spin_unlock(&client->buffer_lock);
  
  	kill_fasync(&client->fasync, SIGIO, POLL_IN);
  }
  
  static void joydev_event(struct input_handle *handle,
  			 unsigned int type, unsigned int code, int value)

  {
  	struct joydev *joydev = handle->private;

  	struct joydev_client *client;

  	struct js_event event;
  
  	switch (type) {

  	case EV_KEY:
  		if (code < BTN_MISC || value == 2)
  			return;
  		event.type = JS_EVENT_BUTTON;
  		event.number = joydev->keymap[code - BTN_MISC];
  		event.value = value;
  		break;

  	case EV_ABS:
  		event.type = JS_EVENT_AXIS;
  		event.number = joydev->absmap[code];
  		event.value = joydev_correct(value,
  					&joydev->corr[event.number]);
  		if (event.value == joydev->abs[event.number])

  			return;

  		joydev->abs[event.number] = event.value;
  		break;
  
  	default:
  		return;

  	}

  	event.time = jiffies_to_msecs(jiffies);

  	rcu_read_lock();

  	list_for_each_entry_rcu(client, &joydev->client_list, node)
  		joydev_pass_event(client, &event);

  	rcu_read_unlock();

  
  	wake_up_interruptible(&joydev->wait);
  }
  
  static int joydev_fasync(int fd, struct file *file, int on)
  {

  	struct joydev_client *client = file->private_data;

  	return fasync_helper(fd, file, on, &client->fasync);

  }

  static void joydev_free(struct device *dev)

  {

  	struct joydev *joydev = container_of(dev, struct joydev, dev);

  	input_put_device(joydev->handle.dev);

  	kfree(joydev);
  }

  static void joydev_attach_client(struct joydev *joydev,
  				 struct joydev_client *client)
  {
  	spin_lock(&joydev->client_lock);
  	list_add_tail_rcu(&client->node, &joydev->client_list);
  	spin_unlock(&joydev->client_lock);

  }
  
  static void joydev_detach_client(struct joydev *joydev,
  				 struct joydev_client *client)
  {
  	spin_lock(&joydev->client_lock);
  	list_del_rcu(&client->node);
  	spin_unlock(&joydev->client_lock);

  	synchronize_rcu();

  }
  
  static int joydev_open_device(struct joydev *joydev)
  {
  	int retval;
  
  	retval = mutex_lock_interruptible(&joydev->mutex);
  	if (retval)
  		return retval;
  
  	if (!joydev->exist)
  		retval = -ENODEV;

  	else if (!joydev->open++) {

  		retval = input_open_device(&joydev->handle);

  		if (retval)
  			joydev->open--;
  	}

  
  	mutex_unlock(&joydev->mutex);
  	return retval;
  }
  
  static void joydev_close_device(struct joydev *joydev)
  {
  	mutex_lock(&joydev->mutex);
  
  	if (joydev->exist && !--joydev->open)
  		input_close_device(&joydev->handle);
  
  	mutex_unlock(&joydev->mutex);
  }
  
  /*
   * Wake up users waiting for IO so they can disconnect from
   * dead device.
   */
  static void joydev_hangup(struct joydev *joydev)
  {
  	struct joydev_client *client;
  
  	spin_lock(&joydev->client_lock);
  	list_for_each_entry(client, &joydev->client_list, node)
  		kill_fasync(&client->fasync, SIGIO, POLL_HUP);
  	spin_unlock(&joydev->client_lock);
  
  	wake_up_interruptible(&joydev->wait);
  }

  static int joydev_release(struct inode *inode, struct file *file)

  {

  	struct joydev_client *client = file->private_data;
  	struct joydev *joydev = client->joydev;

  	joydev_detach_client(joydev, client);

  	kfree(client);

  	joydev_close_device(joydev);

  	put_device(&joydev->dev);

  	return 0;
  }
  
  static int joydev_open(struct inode *inode, struct file *file)
  {

  	struct joydev_client *client;
  	struct joydev *joydev;

  	int i = iminor(inode) - JOYDEV_MINOR_BASE;

  	int error;

  	if (i >= JOYDEV_MINORS)
  		return -ENODEV;

  	error = mutex_lock_interruptible(&joydev_table_mutex);
  	if (error)
  		return error;

  	joydev = joydev_table[i];

  	if (joydev)
  		get_device(&joydev->dev);
  	mutex_unlock(&joydev_table_mutex);

  	if (!joydev)
  		return -ENODEV;

  	client = kzalloc(sizeof(struct joydev_client), GFP_KERNEL);

  	if (!client) {
  		error = -ENOMEM;
  		goto err_put_joydev;
  	}

  	spin_lock_init(&client->buffer_lock);

  	client->joydev = joydev;

  	joydev_attach_client(joydev, client);

  	error = joydev_open_device(joydev);
  	if (error)
  		goto err_free_client;

  	file->private_data = client;

  	nonseekable_open(inode, file);

  	return 0;

  
   err_free_client:

  	joydev_detach_client(joydev, client);

  	kfree(client);
   err_put_joydev:
  	put_device(&joydev->dev);
  	return error;

  }

  static int joydev_generate_startup_event(struct joydev_client *client,
  					 struct input_dev *input,
  					 struct js_event *event)

  {

  	struct joydev *joydev = client->joydev;
  	int have_event;
  
  	spin_lock_irq(&client->buffer_lock);
  
  	have_event = client->startup < joydev->nabs + joydev->nkey;
  
  	if (have_event) {
  
  		event->time = jiffies_to_msecs(jiffies);
  		if (client->startup < joydev->nkey) {
  			event->type = JS_EVENT_BUTTON | JS_EVENT_INIT;
  			event->number = client->startup;
  			event->value = !!test_bit(joydev->keypam[event->number],
  						  input->key);
  		} else {
  			event->type = JS_EVENT_AXIS | JS_EVENT_INIT;
  			event->number = client->startup - joydev->nkey;
  			event->value = joydev->abs[event->number];
  		}
  		client->startup++;
  	}
  
  	spin_unlock_irq(&client->buffer_lock);
  
  	return have_event;
  }
  
  static int joydev_fetch_next_event(struct joydev_client *client,
  				   struct js_event *event)
  {
  	int have_event;
  
  	spin_lock_irq(&client->buffer_lock);
  
  	have_event = client->head != client->tail;
  	if (have_event) {
  		*event = client->buffer[client->tail++];
  		client->tail &= JOYDEV_BUFFER_SIZE - 1;
  	}
  
  	spin_unlock_irq(&client->buffer_lock);
  
  	return have_event;
  }
  
  /*
   * Old joystick interface
   */
  static ssize_t joydev_0x_read(struct joydev_client *client,
  			      struct input_dev *input,
  			      char __user *buf)
  {
  	struct joydev *joydev = client->joydev;
  	struct JS_DATA_TYPE data;
  	int i;
  
  	spin_lock_irq(&input->event_lock);
  
  	/*
  	 * Get device state
  	 */
  	for (data.buttons = i = 0; i < 32 && i < joydev->nkey; i++)
  		data.buttons |=
  			test_bit(joydev->keypam[i], input->key) ? (1 << i) : 0;
  	data.x = (joydev->abs[0] / 256 + 128) >> joydev->glue.JS_CORR.x;
  	data.y = (joydev->abs[1] / 256 + 128) >> joydev->glue.JS_CORR.y;
  
  	/*
  	 * Reset reader's event queue
  	 */
  	spin_lock(&client->buffer_lock);
  	client->startup = 0;
  	client->tail = client->head;
  	spin_unlock(&client->buffer_lock);
  
  	spin_unlock_irq(&input->event_lock);
  
  	if (copy_to_user(buf, &data, sizeof(struct JS_DATA_TYPE)))
  		return -EFAULT;
  
  	return sizeof(struct JS_DATA_TYPE);

  }

  static inline int joydev_data_pending(struct joydev_client *client)
  {
  	struct joydev *joydev = client->joydev;
  
  	return client->startup < joydev->nabs + joydev->nkey ||
  		client->head != client->tail;
  }
  
  static ssize_t joydev_read(struct file *file, char __user *buf,
  			   size_t count, loff_t *ppos)

  {

  	struct joydev_client *client = file->private_data;
  	struct joydev *joydev = client->joydev;

  	struct input_dev *input = joydev->handle.dev;

  	struct js_event event;
  	int retval;

  	if (!joydev->exist)

  		return -ENODEV;
  
  	if (count < sizeof(struct js_event))
  		return -EINVAL;

  	if (count == sizeof(struct JS_DATA_TYPE))
  		return joydev_0x_read(client, input, buf);

  	if (!joydev_data_pending(client) && (file->f_flags & O_NONBLOCK))

  		return -EAGAIN;

  	retval = wait_event_interruptible(joydev->wait,

  			!joydev->exist || joydev_data_pending(client));

  	if (retval)
  		return retval;

  	if (!joydev->exist)

  		return -ENODEV;

  	while (retval + sizeof(struct js_event) <= count &&
  	       joydev_generate_startup_event(client, input, &event)) {

  
  		if (copy_to_user(buf + retval, &event, sizeof(struct js_event)))
  			return -EFAULT;

  		retval += sizeof(struct js_event);
  	}

  	while (retval + sizeof(struct js_event) <= count &&
  	       joydev_fetch_next_event(client, &event)) {

  		if (copy_to_user(buf + retval, &event, sizeof(struct js_event)))

  			return -EFAULT;

  		retval += sizeof(struct js_event);
  	}
  
  	return retval;
  }
  
  /* No kernel lock - fine */
  static unsigned int joydev_poll(struct file *file, poll_table *wait)
  {

  	struct joydev_client *client = file->private_data;
  	struct joydev *joydev = client->joydev;

  	poll_wait(file, &joydev->wait, wait);

  	return (joydev_data_pending(client) ? (POLLIN | POLLRDNORM) : 0) |
  		(joydev->exist ?  0 : (POLLHUP | POLLERR));

  }

  static int joydev_handle_JSIOCSAXMAP(struct joydev *joydev,
  				     void __user *argp, size_t len)
  {
  	__u8 *abspam;
  	int i;
  	int retval = 0;
  
  	len = min(len, sizeof(joydev->abspam));
  
  	/* Validate the map. */
  	abspam = kmalloc(len, GFP_KERNEL);
  	if (!abspam)
  		return -ENOMEM;
  
  	if (copy_from_user(abspam, argp, len)) {
  		retval = -EFAULT;
  		goto out;
  	}
  
  	for (i = 0; i < joydev->nabs; i++) {
  		if (abspam[i] > ABS_MAX) {
  			retval = -EINVAL;
  			goto out;
  		}
  	}
  
  	memcpy(joydev->abspam, abspam, len);

  	for (i = 0; i < joydev->nabs; i++)
  		joydev->absmap[joydev->abspam[i]] = i;

   out:
  	kfree(abspam);
  	return retval;
  }
  
  static int joydev_handle_JSIOCSBTNMAP(struct joydev *joydev,
  				      void __user *argp, size_t len)
  {
  	__u16 *keypam;
  	int i;
  	int retval = 0;
  
  	len = min(len, sizeof(joydev->keypam));
  
  	/* Validate the map. */
  	keypam = kmalloc(len, GFP_KERNEL);
  	if (!keypam)
  		return -ENOMEM;
  
  	if (copy_from_user(keypam, argp, len)) {
  		retval = -EFAULT;
  		goto out;
  	}
  
  	for (i = 0; i < joydev->nkey; i++) {
  		if (keypam[i] > KEY_MAX || keypam[i] < BTN_MISC) {
  			retval = -EINVAL;
  			goto out;
  		}
  	}
  
  	memcpy(joydev->keypam, keypam, len);
  
  	for (i = 0; i < joydev->nkey; i++)
  		joydev->keymap[keypam[i] - BTN_MISC] = i;
  
   out:
  	kfree(keypam);
  	return retval;
  }

  static int joydev_ioctl_common(struct joydev *joydev,
  				unsigned int cmd, void __user *argp)

  {

  	struct input_dev *dev = joydev->handle.dev;

  	size_t len;

  	int i;

  	const char *name;

  	/* Process fixed-sized commands. */

  	switch (cmd) {

  	case JS_SET_CAL:
  		return copy_from_user(&joydev->glue.JS_CORR, argp,

  				sizeof(joydev->glue.JS_CORR)) ? -EFAULT : 0;

  	case JS_GET_CAL:
  		return copy_to_user(argp, &joydev->glue.JS_CORR,

  				sizeof(joydev->glue.JS_CORR)) ? -EFAULT : 0;

  	case JS_SET_TIMEOUT:
  		return get_user(joydev->glue.JS_TIMEOUT, (s32 __user *) argp);

  	case JS_GET_TIMEOUT:
  		return put_user(joydev->glue.JS_TIMEOUT, (s32 __user *) argp);

  	case JSIOCGVERSION:
  		return put_user(JS_VERSION, (__u32 __user *) argp);

  	case JSIOCGAXES:
  		return put_user(joydev->nabs, (__u8 __user *) argp);

  	case JSIOCGBUTTONS:
  		return put_user(joydev->nkey, (__u8 __user *) argp);

  	case JSIOCSCORR:
  		if (copy_from_user(joydev->corr, argp,
  			      sizeof(joydev->corr[0]) * joydev->nabs))

  			return -EFAULT;

  		for (i = 0; i < joydev->nabs; i++) {

  			int val = input_abs_get_val(dev, joydev->abspam[i]);
  			joydev->abs[i] = joydev_correct(val, &joydev->corr[i]);

  		}
  		return 0;

  	case JSIOCGCORR:
  		return copy_to_user(argp, joydev->corr,
  			sizeof(joydev->corr[0]) * joydev->nabs) ? -EFAULT : 0;

  	}
  
  	/*
  	 * Process variable-sized commands (the axis and button map commands
  	 * are considered variable-sized to decouple them from the values of
  	 * ABS_MAX and KEY_MAX).
  	 */
  	switch (cmd & ~IOCSIZE_MASK) {
  
  	case (JSIOCSAXMAP & ~IOCSIZE_MASK):

  		return joydev_handle_JSIOCSAXMAP(joydev, argp, _IOC_SIZE(cmd));

  	case (JSIOCGAXMAP & ~IOCSIZE_MASK):
  		len = min_t(size_t, _IOC_SIZE(cmd), sizeof(joydev->abspam));

  		return copy_to_user(argp, joydev->abspam, len) ? -EFAULT : len;

  
  	case (JSIOCSBTNMAP & ~IOCSIZE_MASK):

  		return joydev_handle_JSIOCSBTNMAP(joydev, argp, _IOC_SIZE(cmd));

  	case (JSIOCGBTNMAP & ~IOCSIZE_MASK):
  		len = min_t(size_t, _IOC_SIZE(cmd), sizeof(joydev->keypam));

  		return copy_to_user(argp, joydev->keypam, len) ? -EFAULT : len;

  	case JSIOCGNAME(0):
  		name = dev->name;
  		if (!name)
  			return 0;
  
  		len = min_t(size_t, _IOC_SIZE(cmd), strlen(name) + 1);
  		return copy_to_user(argp, name, len) ? -EFAULT : len;

  	}

  	return -EINVAL;
  }

  #ifdef CONFIG_COMPAT

  static long joydev_compat_ioctl(struct file *file,
  				unsigned int cmd, unsigned long arg)

  {

  	struct joydev_client *client = file->private_data;
  	struct joydev *joydev = client->joydev;

  	void __user *argp = (void __user *)arg;
  	s32 tmp32;
  	struct JS_DATA_SAVE_TYPE_32 ds32;

  	int retval;

  	retval = mutex_lock_interruptible(&joydev->mutex);
  	if (retval)
  		return retval;
  
  	if (!joydev->exist) {
  		retval = -ENODEV;
  		goto out;
  	}
  
  	switch (cmd) {

  	case JS_SET_TIMELIMIT:

  		retval = get_user(tmp32, (s32 __user *) arg);
  		if (retval == 0)

  			joydev->glue.JS_TIMELIMIT = tmp32;
  		break;

  	case JS_GET_TIMELIMIT:
  		tmp32 = joydev->glue.JS_TIMELIMIT;

  		retval = put_user(tmp32, (s32 __user *) arg);

  		break;
  
  	case JS_SET_ALL:

  		retval = copy_from_user(&ds32, argp,
  					sizeof(ds32)) ? -EFAULT : 0;
  		if (retval == 0) {

  			joydev->glue.JS_TIMEOUT    = ds32.JS_TIMEOUT;
  			joydev->glue.BUSY          = ds32.BUSY;
  			joydev->glue.JS_EXPIRETIME = ds32.JS_EXPIRETIME;
  			joydev->glue.JS_TIMELIMIT  = ds32.JS_TIMELIMIT;
  			joydev->glue.JS_SAVE       = ds32.JS_SAVE;
  			joydev->glue.JS_CORR       = ds32.JS_CORR;
  		}
  		break;
  
  	case JS_GET_ALL:
  		ds32.JS_TIMEOUT    = joydev->glue.JS_TIMEOUT;
  		ds32.BUSY          = joydev->glue.BUSY;
  		ds32.JS_EXPIRETIME = joydev->glue.JS_EXPIRETIME;
  		ds32.JS_TIMELIMIT  = joydev->glue.JS_TIMELIMIT;
  		ds32.JS_SAVE       = joydev->glue.JS_SAVE;
  		ds32.JS_CORR       = joydev->glue.JS_CORR;

  		retval = copy_to_user(argp, &ds32, sizeof(ds32)) ? -EFAULT : 0;

  		break;
  
  	default:

  		retval = joydev_ioctl_common(joydev, cmd, argp);
  		break;

  	}

  
   out:
  	mutex_unlock(&joydev->mutex);
  	return retval;

  }
  #endif /* CONFIG_COMPAT */

  static long joydev_ioctl(struct file *file,
  			 unsigned int cmd, unsigned long arg)

  {

  	struct joydev_client *client = file->private_data;
  	struct joydev *joydev = client->joydev;

  	void __user *argp = (void __user *)arg;

  	int retval;

  	retval = mutex_lock_interruptible(&joydev->mutex);
  	if (retval)
  		return retval;

  	if (!joydev->exist) {
  		retval = -ENODEV;
  		goto out;

  	}

  
  	switch (cmd) {
  
  	case JS_SET_TIMELIMIT:
  		retval = get_user(joydev->glue.JS_TIMELIMIT,
  				  (long __user *) arg);
  		break;
  
  	case JS_GET_TIMELIMIT:
  		retval = put_user(joydev->glue.JS_TIMELIMIT,
  				  (long __user *) arg);
  		break;
  
  	case JS_SET_ALL:
  		retval = copy_from_user(&joydev->glue, argp,
  					sizeof(joydev->glue)) ? -EFAULT: 0;
  		break;
  
  	case JS_GET_ALL:
  		retval = copy_to_user(argp, &joydev->glue,
  				      sizeof(joydev->glue)) ? -EFAULT : 0;
  		break;
  
  	default:
  		retval = joydev_ioctl_common(joydev, cmd, argp);
  		break;
  	}
   out:
  	mutex_unlock(&joydev->mutex);
  	return retval;

  }

  static const struct file_operations joydev_fops = {

  	.owner		= THIS_MODULE,
  	.read		= joydev_read,
  	.poll		= joydev_poll,
  	.open		= joydev_open,
  	.release	= joydev_release,
  	.unlocked_ioctl	= joydev_ioctl,

  #ifdef CONFIG_COMPAT

  	.compat_ioctl	= joydev_compat_ioctl,

  #endif

  	.fasync		= joydev_fasync,

  	.llseek		= no_llseek,

  };

  static int joydev_install_chrdev(struct joydev *joydev)
  {
  	joydev_table[joydev->minor] = joydev;
  	return 0;
  }
  
  static void joydev_remove_chrdev(struct joydev *joydev)
  {
  	mutex_lock(&joydev_table_mutex);
  	joydev_table[joydev->minor] = NULL;
  	mutex_unlock(&joydev_table_mutex);
  }
  
  /*

   * Mark device non-existent. This disables writes, ioctls and

   * prevents new users from opening the device. Already posted
   * blocking reads will stay, however new ones will fail.
   */
  static void joydev_mark_dead(struct joydev *joydev)
  {
  	mutex_lock(&joydev->mutex);

  	joydev->exist = false;

  	mutex_unlock(&joydev->mutex);
  }
  
  static void joydev_cleanup(struct joydev *joydev)
  {
  	struct input_handle *handle = &joydev->handle;
  
  	joydev_mark_dead(joydev);
  	joydev_hangup(joydev);
  	joydev_remove_chrdev(joydev);

  	/* joydev is marked dead so no one else accesses joydev->open */

  	if (joydev->open)
  		input_close_device(handle);
  }

  
  static bool joydev_match(struct input_handler *handler, struct input_dev *dev)
  {
  	/* Avoid touchpads and touchscreens */
  	if (test_bit(EV_KEY, dev->evbit) && test_bit(BTN_TOUCH, dev->keybit))
  		return false;
  
  	/* Avoid tablets, digitisers and similar devices */
  	if (test_bit(EV_KEY, dev->evbit) && test_bit(BTN_DIGI, dev->keybit))
  		return false;
  
  	return true;
  }

  static int joydev_connect(struct input_handler *handler, struct input_dev *dev,
  			  const struct input_device_id *id)

  {
  	struct joydev *joydev;
  	int i, j, t, minor;

  	int error;

  	for (minor = 0; minor < JOYDEV_MINORS; minor++)
  		if (!joydev_table[minor])
  			break;

  	if (minor == JOYDEV_MINORS) {

  		pr_err("no more free joydev devices
  ");

  		return -ENFILE;

  	}

  	joydev = kzalloc(sizeof(struct joydev), GFP_KERNEL);
  	if (!joydev)
  		return -ENOMEM;

  	INIT_LIST_HEAD(&joydev->client_list);

  	spin_lock_init(&joydev->client_lock);
  	mutex_init(&joydev->mutex);

  	init_waitqueue_head(&joydev->wait);

  	dev_set_name(&joydev->dev, "js%d", minor);

  	joydev->exist = true;

  	joydev->minor = minor;

  	joydev->handle.dev = input_get_device(dev);

  	joydev->handle.name = dev_name(&joydev->dev);

  	joydev->handle.handler = handler;
  	joydev->handle.private = joydev;

  	for (i = 0; i < ABS_CNT; i++)

  		if (test_bit(i, dev->absbit)) {
  			joydev->absmap[i] = joydev->nabs;
  			joydev->abspam[joydev->nabs] = i;
  			joydev->nabs++;
  		}
  
  	for (i = BTN_JOYSTICK - BTN_MISC; i < KEY_MAX - BTN_MISC + 1; i++)
  		if (test_bit(i + BTN_MISC, dev->keybit)) {
  			joydev->keymap[i] = joydev->nkey;
  			joydev->keypam[joydev->nkey] = i + BTN_MISC;
  			joydev->nkey++;
  		}

  	for (i = 0; i < BTN_JOYSTICK - BTN_MISC; i++)

  		if (test_bit(i + BTN_MISC, dev->keybit)) {
  			joydev->keymap[i] = joydev->nkey;
  			joydev->keypam[joydev->nkey] = i + BTN_MISC;
  			joydev->nkey++;
  		}
  
  	for (i = 0; i < joydev->nabs; i++) {
  		j = joydev->abspam[i];

  		if (input_abs_get_max(dev, j) == input_abs_get_min(dev, j)) {

  			joydev->corr[i].type = JS_CORR_NONE;

  			joydev->abs[i] = input_abs_get_val(dev, j);

  			continue;
  		}
  		joydev->corr[i].type = JS_CORR_BROKEN;

  		joydev->corr[i].prec = input_abs_get_fuzz(dev, j);
  
  		t = (input_abs_get_max(dev, j) + input_abs_get_min(dev, j)) / 2;
  		joydev->corr[i].coef[0] = t - input_abs_get_flat(dev, j);
  		joydev->corr[i].coef[1] = t + input_abs_get_flat(dev, j);

  		t = (input_abs_get_max(dev, j) - input_abs_get_min(dev, j)) / 2
  			- 2 * input_abs_get_flat(dev, j);

  		if (t) {
  			joydev->corr[i].coef[2] = (1 << 29) / t;
  			joydev->corr[i].coef[3] = (1 << 29) / t;

  			joydev->abs[i] =
  				joydev_correct(input_abs_get_val(dev, j),
  					       joydev->corr + i);

  		}

  	}

  	joydev->dev.devt = MKDEV(INPUT_MAJOR, JOYDEV_MINOR_BASE + minor);

  	joydev->dev.class = &input_class;
  	joydev->dev.parent = &dev->dev;

  	joydev->dev.release = joydev_free;
  	device_initialize(&joydev->dev);

  	error = input_register_handle(&joydev->handle);

  	if (error)

  		goto err_free_joydev;

  	error = joydev_install_chrdev(joydev);

  	if (error)

  		goto err_unregister_handle;
  
  	error = device_add(&joydev->dev);
  	if (error)
  		goto err_cleanup_joydev;

  
  	return 0;

   err_cleanup_joydev:
  	joydev_cleanup(joydev);
   err_unregister_handle:
  	input_unregister_handle(&joydev->handle);

   err_free_joydev:

  	put_device(&joydev->dev);

  	return error;

  }
  
  static void joydev_disconnect(struct input_handle *handle)
  {
  	struct joydev *joydev = handle->private;

  	device_del(&joydev->dev);

  	joydev_cleanup(joydev);
  	input_unregister_handle(handle);

  	put_device(&joydev->dev);

  }

  static const struct input_device_id joydev_ids[] = {

  	{

  		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
  				INPUT_DEVICE_ID_MATCH_ABSBIT,

  		.evbit = { BIT_MASK(EV_ABS) },
  		.absbit = { BIT_MASK(ABS_X) },

  	},
  	{

  		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
  				INPUT_DEVICE_ID_MATCH_ABSBIT,

  		.evbit = { BIT_MASK(EV_ABS) },
  		.absbit = { BIT_MASK(ABS_WHEEL) },

  	},
  	{

  		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
  				INPUT_DEVICE_ID_MATCH_ABSBIT,

  		.evbit = { BIT_MASK(EV_ABS) },
  		.absbit = { BIT_MASK(ABS_THROTTLE) },

  	},

  	{
  		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
  				INPUT_DEVICE_ID_MATCH_KEYBIT,
  		.evbit = { BIT_MASK(EV_KEY) },
  		.keybit = {[BIT_WORD(BTN_JOYSTICK)] = BIT_MASK(BTN_JOYSTICK) },
  	},
  	{
  		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
  				INPUT_DEVICE_ID_MATCH_KEYBIT,
  		.evbit = { BIT_MASK(EV_KEY) },
  		.keybit = { [BIT_WORD(BTN_GAMEPAD)] = BIT_MASK(BTN_GAMEPAD) },
  	},
  	{
  		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
  				INPUT_DEVICE_ID_MATCH_KEYBIT,
  		.evbit = { BIT_MASK(EV_KEY) },
  		.keybit = { [BIT_WORD(BTN_TRIGGER_HAPPY)] = BIT_MASK(BTN_TRIGGER_HAPPY) },
  	},

  	{ }	/* Terminating entry */

  };
  
  MODULE_DEVICE_TABLE(input, joydev_ids);
  
  static struct input_handler joydev_handler = {

  	.event		= joydev_event,

  	.match		= joydev_match,

  	.connect	= joydev_connect,
  	.disconnect	= joydev_disconnect,
  	.fops		= &joydev_fops,
  	.minor		= JOYDEV_MINOR_BASE,
  	.name		= "joydev",
  	.id_table	= joydev_ids,

  };
  
  static int __init joydev_init(void)
  {

  	return input_register_handler(&joydev_handler);

  }
  
  static void __exit joydev_exit(void)
  {
  	input_unregister_handler(&joydev_handler);
  }
  
  module_init(joydev_init);
  module_exit(joydev_exit);