// SPDX-License-Identifier: GPL-2.0-or-later

  /*
   * Joystick device driver for the input driver suite.
   *
   * Copyright (c) 1999-2002 Vojtech Pavlik
   * Copyright (c) 1999 Colin Van Dyke

   */

  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

  #include <asm/io.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/module.h>
  #include <linux/poll.h>
  #include <linux/init.h>

  #include <linux/device.h>

  #include <linux/cdev.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;

  	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;

  	struct cdev cdev;

  	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 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 clamp(value, -32767, 32767);

  }

  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 void joydev_refresh_state(struct joydev *joydev)
  {
  	struct input_dev *dev = joydev->handle.dev;
  	int i, val;
  
  	for (i = 0; i < joydev->nabs; i++) {
  		val = input_abs_get_val(dev, joydev->abspam[i]);
  		joydev->abs[i] = joydev_correct(val, &joydev->corr[i]);
  	}
  }

  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--;

  		else
  			joydev_refresh_state(joydev);

  	}

  
  	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);

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

  	struct joydev *joydev =
  			container_of(inode->i_cdev, struct joydev, cdev);

  	struct joydev_client *client;

  	int error;

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

  	if (!client)
  		return -ENOMEM;

  	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;

  	stream_open(inode, file);

  	return 0;

  
   err_free_client:

  	joydev_detach_client(joydev, client);

  	kfree(client);

  	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 __poll_t 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) ? (EPOLLIN | EPOLLRDNORM) : 0) |
  		(joydev->exist ?  0 : (EPOLLHUP | EPOLLERR));

  }

  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 = memdup_user(argp, len);

  	if (IS_ERR(abspam))
  		return PTR_ERR(abspam);

  
  	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 = memdup_user(argp, len);

  	if (IS_ERR(keypam))
  		return PTR_ERR(keypam);

  
  	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,

  };

  /*

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

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

  /*
   * These codes are copied from from hid-ids.h, unfortunately there is no common
   * usb_ids/bt_ids.h header.
   */
  #define USB_VENDOR_ID_SONY			0x054c
  #define USB_DEVICE_ID_SONY_PS3_CONTROLLER		0x0268
  #define USB_DEVICE_ID_SONY_PS4_CONTROLLER		0x05c4
  #define USB_DEVICE_ID_SONY_PS4_CONTROLLER_2		0x09cc
  #define USB_DEVICE_ID_SONY_PS4_CONTROLLER_DONGLE	0x0ba0
  
  #define USB_VENDOR_ID_THQ			0x20d6
  #define USB_DEVICE_ID_THQ_PS3_UDRAW			0xcb17
  
  #define ACCEL_DEV(vnd, prd)						\
  	{								\
  		.flags = INPUT_DEVICE_ID_MATCH_VENDOR |			\
  				INPUT_DEVICE_ID_MATCH_PRODUCT |		\
  				INPUT_DEVICE_ID_MATCH_PROPBIT,		\
  		.vendor = (vnd),					\
  		.product = (prd),					\
  		.propbit = { BIT_MASK(INPUT_PROP_ACCELEROMETER) },	\
  	}
  
  static const struct input_device_id joydev_blacklist[] = {
  	/* Avoid touchpads and touchscreens */
  	{
  		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
  				INPUT_DEVICE_ID_MATCH_KEYBIT,
  		.evbit = { BIT_MASK(EV_KEY) },
  		.keybit = { [BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH) },
  	},
  	/* Avoid tablets, digitisers and similar devices */
  	{
  		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
  				INPUT_DEVICE_ID_MATCH_KEYBIT,
  		.evbit = { BIT_MASK(EV_KEY) },
  		.keybit = { [BIT_WORD(BTN_DIGI)] = BIT_MASK(BTN_DIGI) },
  	},
  	/* Disable accelerometers on composite devices */
  	ACCEL_DEV(USB_VENDOR_ID_SONY, USB_DEVICE_ID_SONY_PS3_CONTROLLER),
  	ACCEL_DEV(USB_VENDOR_ID_SONY, USB_DEVICE_ID_SONY_PS4_CONTROLLER),
  	ACCEL_DEV(USB_VENDOR_ID_SONY, USB_DEVICE_ID_SONY_PS4_CONTROLLER_2),
  	ACCEL_DEV(USB_VENDOR_ID_SONY, USB_DEVICE_ID_SONY_PS4_CONTROLLER_DONGLE),
  	ACCEL_DEV(USB_VENDOR_ID_THQ, USB_DEVICE_ID_THQ_PS3_UDRAW),
  	{ /* sentinel */ }
  };
  
  static bool joydev_dev_is_blacklisted(struct input_dev *dev)
  {
  	const struct input_device_id *id;
  
  	for (id = joydev_blacklist; id->flags; id++) {
  		if (input_match_device_id(dev, id)) {
  			dev_dbg(&dev->dev,
  				"joydev: blacklisting '%s'
  ", dev->name);
  			return true;
  		}
  	}
  
  	return false;
  }

  static bool joydev_dev_is_absolute_mouse(struct input_dev *dev)
  {
  	DECLARE_BITMAP(jd_scratch, KEY_CNT);

  	bool ev_match = false;

  
  	BUILD_BUG_ON(ABS_CNT > KEY_CNT || EV_CNT > KEY_CNT);
  
  	/*
  	 * Virtualization (VMware, etc) and remote management (HP
  	 * ILO2) solutions use absolute coordinates for their virtual
  	 * pointing devices so that there is one-to-one relationship
  	 * between pointer position on the host screen and virtual
  	 * guest screen, and so their mice use ABS_X, ABS_Y and 3
  	 * primary button events. This clashes with what joydev
  	 * considers to be joysticks (a device with at minimum ABS_X
  	 * axis).
  	 *
  	 * Here we are trying to separate absolute mice from
  	 * joysticks. A device is, for joystick detection purposes,
  	 * considered to be an absolute mouse if the following is
  	 * true:
  	 *

  	 * 1) Event types are exactly
  	 *      EV_ABS, EV_KEY and EV_SYN
  	 *    or
  	 *      EV_ABS, EV_KEY, EV_SYN and EV_MSC
  	 *    or
  	 *      EV_ABS, EV_KEY, EV_SYN, EV_MSC and EV_REL.

  	 * 2) Absolute events are exactly ABS_X and ABS_Y.
  	 * 3) Keys are exactly BTN_LEFT, BTN_RIGHT and BTN_MIDDLE.
  	 * 4) Device is not on "Amiga" bus.
  	 */
  
  	bitmap_zero(jd_scratch, EV_CNT);

  	/* VMware VMMouse, HP ILO2 */

  	__set_bit(EV_ABS, jd_scratch);
  	__set_bit(EV_KEY, jd_scratch);
  	__set_bit(EV_SYN, jd_scratch);

  	if (bitmap_equal(jd_scratch, dev->evbit, EV_CNT))
  		ev_match = true;
  
  	/* HP ILO2, AMI BMC firmware */
  	__set_bit(EV_MSC, jd_scratch);
  	if (bitmap_equal(jd_scratch, dev->evbit, EV_CNT))
  		ev_match = true;
  
  	/* VMware Virtual USB Mouse, QEMU USB Tablet, ATEN BMC firmware */
  	__set_bit(EV_REL, jd_scratch);
  	if (bitmap_equal(jd_scratch, dev->evbit, EV_CNT))
  		ev_match = true;
  
  	if (!ev_match)

  		return false;
  
  	bitmap_zero(jd_scratch, ABS_CNT);
  	__set_bit(ABS_X, jd_scratch);
  	__set_bit(ABS_Y, jd_scratch);
  	if (!bitmap_equal(dev->absbit, jd_scratch, ABS_CNT))
  		return false;
  
  	bitmap_zero(jd_scratch, KEY_CNT);
  	__set_bit(BTN_LEFT, jd_scratch);
  	__set_bit(BTN_RIGHT, jd_scratch);
  	__set_bit(BTN_MIDDLE, jd_scratch);
  
  	if (!bitmap_equal(dev->keybit, jd_scratch, KEY_CNT))
  		return false;
  
  	/*
  	 * Amiga joystick (amijoy) historically uses left/middle/right
  	 * button events.
  	 */
  	if (dev->id.bustype == BUS_AMIGA)
  		return false;
  
  	return true;
  }

  
  static bool joydev_match(struct input_handler *handler, struct input_dev *dev)
  {

  	/* Disable blacklisted devices */
  	if (joydev_dev_is_blacklisted(dev))

  		return false;

  	/* Avoid absolute mice */
  	if (joydev_dev_is_absolute_mouse(dev))
  		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, dev_no;

  	int error;

  	minor = input_get_new_minor(JOYDEV_MINOR_BASE, JOYDEV_MINORS, true);
  	if (minor < 0) {
  		error = minor;
  		pr_err("failed to reserve new minor: %d
  ", error);
  		return error;

  	}

  	joydev = kzalloc(sizeof(struct joydev), GFP_KERNEL);

  	if (!joydev) {
  		error = -ENOMEM;
  		goto err_free_minor;
  	}

  	INIT_LIST_HEAD(&joydev->client_list);

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

  	init_waitqueue_head(&joydev->wait);

  	joydev->exist = true;

  
  	dev_no = minor;
  	/* Normalize device number if it falls into legacy range */
  	if (dev_no < JOYDEV_MINOR_BASE + JOYDEV_MINORS)
  		dev_no -= JOYDEV_MINOR_BASE;
  	dev_set_name(&joydev->dev, "js%d", dev_no);

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

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

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

  	for_each_set_bit(i, dev->absbit, ABS_CNT) {
  		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;

  			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->dev.devt = MKDEV(INPUT_MAJOR, 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;

  	cdev_init(&joydev->cdev, &joydev_fops);

  	error = cdev_device_add(&joydev->cdev, &joydev->dev);

  	if (error)
  		goto err_cleanup_joydev;

  
  	return 0;

   err_cleanup_joydev:
  	joydev_cleanup(joydev);

  	input_unregister_handle(&joydev->handle);

   err_free_joydev:

  	put_device(&joydev->dev);

   err_free_minor:
  	input_free_minor(minor);

  	return error;

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

  	cdev_device_del(&joydev->cdev, &joydev->dev);

  	joydev_cleanup(joydev);

  	input_free_minor(MINOR(joydev->dev.devt));

  	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_Z) },
  	},
  	{
  		.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,

  	.legacy_minors	= true,

  	.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);