/*
   * drivers/macintosh/mac_hid.c
   *
   * HID support stuff for Macintosh computers.
   *
   * Copyright (C) 2000 Franz Sirl.
   *
   * This file will soon be removed in favor of an uinput userspace tool.
   */
  
  #include <linux/init.h>
  #include <linux/proc_fs.h>
  #include <linux/sysctl.h>
  #include <linux/input.h>
  #include <linux/module.h>
  #include <linux/slab.h>
  
  MODULE_LICENSE("GPL");
  
  static int mouse_emulate_buttons;
  static int mouse_button2_keycode = KEY_RIGHTCTRL;	/* right control key */
  static int mouse_button3_keycode = KEY_RIGHTALT;	/* right option key */
  
  static struct input_dev *mac_hid_emumouse_dev;
  
  static DEFINE_MUTEX(mac_hid_emumouse_mutex);
  
  static int mac_hid_create_emumouse(void)
  {
  	static struct lock_class_key mac_hid_emumouse_dev_event_class;
  	static struct lock_class_key mac_hid_emumouse_dev_mutex_class;
  	int err;
  
  	mac_hid_emumouse_dev = input_allocate_device();
  	if (!mac_hid_emumouse_dev)
  		return -ENOMEM;
  
  	lockdep_set_class(&mac_hid_emumouse_dev->event_lock,
  			  &mac_hid_emumouse_dev_event_class);
  	lockdep_set_class(&mac_hid_emumouse_dev->mutex,
  			  &mac_hid_emumouse_dev_mutex_class);
  
  	mac_hid_emumouse_dev->name = "Macintosh mouse button emulation";
  	mac_hid_emumouse_dev->id.bustype = BUS_ADB;
  	mac_hid_emumouse_dev->id.vendor = 0x0001;
  	mac_hid_emumouse_dev->id.product = 0x0001;
  	mac_hid_emumouse_dev->id.version = 0x0100;
  
  	mac_hid_emumouse_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REL);
  	mac_hid_emumouse_dev->keybit[BIT_WORD(BTN_MOUSE)] =
  		BIT_MASK(BTN_LEFT) | BIT_MASK(BTN_MIDDLE) | BIT_MASK(BTN_RIGHT);
  	mac_hid_emumouse_dev->relbit[0] = BIT_MASK(REL_X) | BIT_MASK(REL_Y);
  
  	err = input_register_device(mac_hid_emumouse_dev);
  	if (err) {
  		input_free_device(mac_hid_emumouse_dev);
  		mac_hid_emumouse_dev = NULL;
  		return err;
  	}
  
  	return 0;
  }
  
  static void mac_hid_destroy_emumouse(void)
  {
  	input_unregister_device(mac_hid_emumouse_dev);
  	mac_hid_emumouse_dev = NULL;
  }
  
  static bool mac_hid_emumouse_filter(struct input_handle *handle,
  				    unsigned int type, unsigned int code,
  				    int value)
  {
  	unsigned int btn;
  
  	if (type != EV_KEY)
  		return false;
  
  	if (code == mouse_button2_keycode)
  		btn = BTN_MIDDLE;
  	else if (code == mouse_button3_keycode)
  		btn = BTN_RIGHT;
  	else
  		return false;
  
  	input_report_key(mac_hid_emumouse_dev, btn, value);
  	input_sync(mac_hid_emumouse_dev);
  
  	return true;
  }
  
  static int mac_hid_emumouse_connect(struct input_handler *handler,
  				    struct input_dev *dev,
  				    const struct input_device_id *id)
  {
  	struct input_handle *handle;
  	int error;
  
  	/* Don't bind to ourselves */
  	if (dev == mac_hid_emumouse_dev)
  		return -ENODEV;
  
  	handle = kzalloc(sizeof(struct input_handle), GFP_KERNEL);
  	if (!handle)
  		return -ENOMEM;
  
  	handle->dev = dev;
  	handle->handler = handler;
  	handle->name = "mac-button-emul";
  
  	error = input_register_handle(handle);
  	if (error) {
  		printk(KERN_ERR
  			"mac_hid: Failed to register button emulation handle, "
  			"error %d
  ", error);
  		goto err_free;
  	}
  
  	error = input_open_device(handle);
  	if (error) {
  		printk(KERN_ERR
  			"mac_hid: Failed to open input device, error %d
  ",
  			error);
  		goto err_unregister;
  	}
  
  	return 0;
  
   err_unregister:
  	input_unregister_handle(handle);
   err_free:
  	kfree(handle);
  	return error;
  }
  
  static void mac_hid_emumouse_disconnect(struct input_handle *handle)
  {
  	input_close_device(handle);
  	input_unregister_handle(handle);
  	kfree(handle);
  }
  
  static const struct input_device_id mac_hid_emumouse_ids[] = {
  	{
  		.flags = INPUT_DEVICE_ID_MATCH_EVBIT,
  		.evbit = { BIT_MASK(EV_KEY) },
  	},
  	{ },
  };
  
  MODULE_DEVICE_TABLE(input, mac_hid_emumouse_ids);
  
  static struct input_handler mac_hid_emumouse_handler = {
  	.filter		= mac_hid_emumouse_filter,
  	.connect	= mac_hid_emumouse_connect,
  	.disconnect	= mac_hid_emumouse_disconnect,
  	.name		= "mac-button-emul",
  	.id_table	= mac_hid_emumouse_ids,
  };
  
  static int mac_hid_start_emulation(void)
  {
  	int err;
  
  	err = mac_hid_create_emumouse();
  	if (err)
  		return err;
  
  	err = input_register_handler(&mac_hid_emumouse_handler);
  	if (err) {
  		mac_hid_destroy_emumouse();
  		return err;
  	}
  
  	return 0;
  }
  
  static void mac_hid_stop_emulation(void)
  {
  	input_unregister_handler(&mac_hid_emumouse_handler);
  	mac_hid_destroy_emumouse();
  }
  
  static int mac_hid_toggle_emumouse(struct ctl_table *table, int write,
  				   void __user *buffer, size_t *lenp,
  				   loff_t *ppos)
  {
  	int *valp = table->data;
  	int old_val = *valp;
  	int rc;
  
  	rc = mutex_lock_killable(&mac_hid_emumouse_mutex);
  	if (rc)
  		return rc;
  
  	rc = proc_dointvec(table, write, buffer, lenp, ppos);
  
  	if (rc == 0 && write && *valp != old_val) {
  		if (*valp == 1)
  			rc = mac_hid_start_emulation();
  		else if (*valp == 0)
  			mac_hid_stop_emulation();
  		else
  			rc = -EINVAL;
  	}
  
  	/* Restore the old value in case of error */
  	if (rc)
  		*valp = old_val;
  
  	mutex_unlock(&mac_hid_emumouse_mutex);
  
  	return rc;
  }
  
  /* file(s) in /proc/sys/dev/mac_hid */
  static struct ctl_table mac_hid_files[] = {
  	{
  		.procname	= "mouse_button_emulation",
  		.data		= &mouse_emulate_buttons,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= mac_hid_toggle_emumouse,
  	},
  	{
  		.procname	= "mouse_button2_keycode",
  		.data		= &mouse_button2_keycode,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{
  		.procname	= "mouse_button3_keycode",
  		.data		= &mouse_button3_keycode,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_dointvec,
  	},
  	{ }
  };
  
  /* dir in /proc/sys/dev */
  static struct ctl_table mac_hid_dir[] = {
  	{
  		.procname	= "mac_hid",
  		.maxlen		= 0,
  		.mode		= 0555,
  		.child		= mac_hid_files,
  	},
  	{ }
  };
  
  /* /proc/sys/dev itself, in case that is not there yet */
  static struct ctl_table mac_hid_root_dir[] = {
  	{
  		.procname	= "dev",
  		.maxlen		= 0,
  		.mode		= 0555,
  		.child		= mac_hid_dir,
  	},
  	{ }
  };
  
  static struct ctl_table_header *mac_hid_sysctl_header;
  
  static int __init mac_hid_init(void)
  {
  	mac_hid_sysctl_header = register_sysctl_table(mac_hid_root_dir);
  	if (!mac_hid_sysctl_header)
  		return -ENOMEM;
  
  	return 0;
  }
  module_init(mac_hid_init);
  
  static void __exit mac_hid_exit(void)
  {
  	unregister_sysctl_table(mac_hid_sysctl_header);
  
  	if (mouse_emulate_buttons)
  		mac_hid_stop_emulation();
  }
  module_exit(mac_hid_exit);