Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / input / joydev.c
diff --git a/kernel/drivers/input/joydev.c b/kernel/drivers/input/joydev.c
new file mode 100644 (file)
index 0000000..1d247bc
--- /dev/null
@@ -0,0 +1,1017 @@
+/*
+ * 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 <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>
+#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 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);
+
+       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;
+       nonseekable_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 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,
+};
+
+/*
+ * 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);
+
+       cdev_del(&joydev->cdev);
+
+       /* joydev is marked dead so no one else accesses joydev->open */
+       if (joydev->open)
+               input_close_device(handle);
+}
+
+static bool joydev_dev_is_absolute_mouse(struct input_dev *dev)
+{
+       DECLARE_BITMAP(jd_scratch, KEY_CNT);
+
+       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.
+        * 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);
+       __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))
+               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)
+{
+       /* 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;
+
+       /* 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\n", 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 (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, 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);
+       joydev->cdev.kobj.parent = &joydev->dev.kobj;
+       error = cdev_add(&joydev->cdev, joydev->dev.devt, 1);
+       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);
+ err_free_minor:
+       input_free_minor(minor);
+       return error;
+}
+
+static void joydev_disconnect(struct input_handle *handle)
+{
+       struct joydev *joydev = handle->private;
+
+       device_del(&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_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);