/*
   *  drivers/extcon/extcon_class.c
   *
   *  External connector (extcon) class driver
   *
   * Copyright (C) 2012 Samsung Electronics
   * Author: Donggeun Kim <dg77.kim@samsung.com>
   * Author: MyungJoo Ham <myungjoo.ham@samsung.com>
   *
   * based on android/drivers/switch/switch_class.c
   * Copyright (C) 2008 Google, Inc.
   * Author: Mike Lockwood <lockwood@android.com>
   *
   * This software is licensed under the terms of the GNU General Public
   * License version 2, as published by the Free Software Foundation, and
   * may be copied, distributed, and modified under those terms.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
  */
  
  #include <linux/module.h>
  #include <linux/types.h>
  #include <linux/init.h>
  #include <linux/device.h>
  #include <linux/fs.h>
  #include <linux/err.h>
  #include <linux/extcon.h>
  #include <linux/slab.h>
  #include <linux/sysfs.h>
  
  /*
   * extcon_cable_name suggests the standard cable names for commonly used
   * cable types.
   *
   * However, please do not use extcon_cable_name directly for extcon_dev
   * struct's supported_cable pointer unless your device really supports
   * every single port-type of the following cable names. Please choose cable
   * names that are actually used in your extcon device.
   */
  const char extcon_cable_name[][CABLE_NAME_MAX + 1] = {
  	[EXTCON_USB]		= "USB",
  	[EXTCON_USB_HOST]	= "USB-Host",
  	[EXTCON_TA]		= "TA",
  	[EXTCON_FAST_CHARGER]	= "Fast-charger",
  	[EXTCON_SLOW_CHARGER]	= "Slow-charger",
  	[EXTCON_CHARGE_DOWNSTREAM]	= "Charge-downstream",
  	[EXTCON_HDMI]		= "HDMI",
  	[EXTCON_MHL]		= "MHL",
  	[EXTCON_DVI]		= "DVI",
  	[EXTCON_VGA]		= "VGA",
  	[EXTCON_DOCK]		= "Dock",
  	[EXTCON_LINE_IN]	= "Line-in",
  	[EXTCON_LINE_OUT]	= "Line-out",
  	[EXTCON_MIC_IN]		= "Microphone",
  	[EXTCON_HEADPHONE_OUT]	= "Headphone",
  	[EXTCON_SPDIF_IN]	= "SPDIF-in",
  	[EXTCON_SPDIF_OUT]	= "SPDIF-out",
  	[EXTCON_VIDEO_IN]	= "Video-in",
  	[EXTCON_VIDEO_OUT]	= "Video-out",
  	[EXTCON_MECHANICAL]	= "Mechanical",
  	[EXTCON_HV_PREPARE]	= "High Voltage Prepare",
  	[EXTCON_HV_TA]		= "High Voltage TA",
  	[EXTCON_HV_TA_ERR]	= "Error HV TA",
  	[EXTCON_DESKDOCK]	= "Desk-dock",
  	[EXTCON_DESKDOCK_VB]	= "Desk-dock-VB",
  	[EXTCON_AUDIODOCK]	= "Audio-dock",
  	[EXTCON_SMARTDOCK]	= "Smart-dock",
  	[EXTCON_SMARTDOCK_TA]	= "Smart-dock-TA",
  	[EXTCON_SMARTDOCK_USB]	= "Smart-dock-USB",
  	[EXTCON_MULTIMEDIADOCK]	= "Multimedia-dock",
  	[EXTCON_JIG_UARTOFF]	= "JIG-UART-OFF",
  	[EXTCON_JIG_UARTOFF_VB]	= "JIG-UART-OFF-VB",
  	[EXTCON_JIG_UARTON]	= "JIG-UART-ON",
  	[EXTCON_JIG_USBOFF]	= "JIG-USB-OFF",
  	[EXTCON_JIG_USBON]	= "JIG-USB-ON",
  	[EXTCON_INCOMPATIBLE]	= "Incompatible-TA",
  	[EXTCON_CHARGING_CABLE]	= "Charging-Cable",
  #if defined(CONFIG_MUIC_SUPPORT_HMT_DETECTION)
  	[EXTCON_HMT]		= "HMT",
  #endif
  	[EXTCON_HV_TA_1A]	= "High Voltage 1A Type Cable",
  	[EXTCON_NONE]		= "None",
  };
  
  static struct class *extcon_class;
  #if defined(CONFIG_ANDROID)
  static struct class_compat *switch_class;
  #endif /* CONFIG_ANDROID */
  
  static LIST_HEAD(extcon_dev_list);
  static DEFINE_MUTEX(extcon_dev_list_lock);
  
  /**
   * check_mutually_exclusive - Check if new_state violates mutually_exclusive
   *			      condition.
   * @edev:	the extcon device
   * @new_state:	new cable attach status for @edev
   *
   * Returns 0 if nothing violates. Returns the index + 1 for the first
   * violated condition.
   */
  static int check_mutually_exclusive(struct extcon_dev *edev, u32 new_state)
  {
  	int i = 0;
  
  	if (!edev->mutually_exclusive)
  		return 0;
  
  	for (i = 0; edev->mutually_exclusive[i]; i++) {
  		int weight;
  		u32 correspondants = new_state & edev->mutually_exclusive[i];
  
  		/* calculate the total number of bits set */
  		weight = hweight32(correspondants);
  		if (weight > 1)
  			return i + 1;
  	}
  
  	return 0;
  }
  
  static ssize_t state_show(struct device *dev, struct device_attribute *attr,
  			  char *buf)
  {
  	int i, count = 0;
  	struct extcon_dev *edev = dev_get_drvdata(dev);
  
  	if (edev->print_state) {
  		int ret = edev->print_state(edev, buf);
  
  		if (ret >= 0)
  			return ret;
  		/* Use default if failed */
  	}
  
  	if (edev->max_supported == 0)
  		return sprintf(buf, "%u
  ", edev->state);
  
  	for (i = 0; i < SUPPORTED_CABLE_MAX; i++) {
  		if (!edev->supported_cable[i])
  			break;
  		count += sprintf(buf + count, "%s=%d
  ",
  				 edev->supported_cable[i],
  				 !!(edev->state & (1 << i)));
  	}
  
  	return count;
  }
  
  static ssize_t state_store(struct device *dev, struct device_attribute *attr,
  			   const char *buf, size_t count)
  {
  	u32 state;
  	ssize_t ret = 0;
  	struct extcon_dev *edev = dev_get_drvdata(dev);
  
  	ret = sscanf(buf, "0x%x", &state);
  	if (ret == 0)
  		ret = -EINVAL;
  	else
  		ret = extcon_set_state(edev, state);
  
  	if (ret < 0)
  		return ret;
  
  	return count;
  }
  static DEVICE_ATTR_RW(state);
  
  static ssize_t name_show(struct device *dev, struct device_attribute *attr,
  		char *buf)
  {
  	struct extcon_dev *edev = dev_get_drvdata(dev);
  
  	/* Optional callback given by the user */
  	if (edev->print_name) {
  		int ret = edev->print_name(edev, buf);
  		if (ret >= 0)
  			return ret;
  	}
  
  	return sprintf(buf, "%s
  ", dev_name(&edev->dev));
  }
  static DEVICE_ATTR_RO(name);
  
  static ssize_t cable_name_show(struct device *dev,
  			       struct device_attribute *attr, char *buf)
  {
  	struct extcon_cable *cable = container_of(attr, struct extcon_cable,
  						  attr_name);
  
  	return sprintf(buf, "%s
  ",
  		       cable->edev->supported_cable[cable->cable_index]);
  }
  
  static ssize_t cable_state_show(struct device *dev,
  				struct device_attribute *attr, char *buf)
  {
  	struct extcon_cable *cable = container_of(attr, struct extcon_cable,
  						  attr_state);
  
  	return sprintf(buf, "%d
  ",
  		       extcon_get_cable_state_(cable->edev,
  					       cable->cable_index));
  }
  
  /**
   * extcon_update_state() - Update the cable attach states of the extcon device
   *			   only for the masked bits.
   * @edev:	the extcon device
   * @mask:	the bit mask to designate updated bits.
   * @state:	new cable attach status for @edev
   *
   * Changing the state sends uevent with environment variable containing
   * the name of extcon device (envp[0]) and the state output (envp[1]).
   * Tizen uses this format for extcon device to get events from ports.
   * Android uses this format as well.
   *
   * Note that the notifier provides which bits are changed in the state
   * variable with the val parameter (second) to the callback.
   */
  int extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state)
  {
  	char name_buf[120];
  	char state_buf[120];
  	char *prop_buf;
  	char *envp[3];
  	int env_offset = 0;
  	int length;
  	unsigned long flags;
  
  	spin_lock_irqsave(&edev->lock, flags);
  
  	if (edev->state != ((edev->state & ~mask) | (state & mask))) {
  		u32 old_state = edev->state;
  
  		if (check_mutually_exclusive(edev, (edev->state & ~mask) |
  						   (state & mask))) {
  			spin_unlock_irqrestore(&edev->lock, flags);
  			return -EPERM;
  		}
  
  		edev->state &= ~mask;
  		edev->state |= state & mask;
  
  		raw_notifier_call_chain(&edev->nh, old_state, edev);
  		/* This could be in interrupt handler */
  		prop_buf = (char *)get_zeroed_page(GFP_ATOMIC);
  		if (prop_buf) {
  			length = name_show(&edev->dev, NULL, prop_buf);
  			if (length > 0) {
  				if (prop_buf[length - 1] == '
  ')
  					prop_buf[length - 1] = 0;
  				snprintf(name_buf, sizeof(name_buf),
  					"NAME=%s", prop_buf);
  				envp[env_offset++] = name_buf;
  			}
  			length = state_show(&edev->dev, NULL, prop_buf);
  			if (length > 0) {
  				if (prop_buf[length - 1] == '
  ')
  					prop_buf[length - 1] = 0;
  				snprintf(state_buf, sizeof(state_buf),
  					"STATE=%s", prop_buf);
  				envp[env_offset++] = state_buf;
  			}
  			envp[env_offset] = NULL;
  			/* Unlock early before uevent */
  			spin_unlock_irqrestore(&edev->lock, flags);
  
  			kobject_uevent_env(&edev->dev.kobj, KOBJ_CHANGE, envp);
  			free_page((unsigned long)prop_buf);
  		} else {
  			/* Unlock early before uevent */
  			spin_unlock_irqrestore(&edev->lock, flags);
  
  			dev_err(&edev->dev, "out of memory in extcon_set_state
  ");
  			kobject_uevent(&edev->dev.kobj, KOBJ_CHANGE);
  		}
  	} else {
  		/* No changes */
  		spin_unlock_irqrestore(&edev->lock, flags);
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(extcon_update_state);
  
  /**
   * extcon_set_state() - Set the cable attach states of the extcon device.
   * @edev:	the extcon device
   * @state:	new cable attach status for @edev
   *
   * Note that notifier provides which bits are changed in the state
   * variable with the val parameter (second) to the callback.
   */
  int extcon_set_state(struct extcon_dev *edev, u32 state)
  {
  	return extcon_update_state(edev, 0xffffffff, state);
  }
  EXPORT_SYMBOL_GPL(extcon_set_state);
  
  /**
   * extcon_find_cable_index() - Get the cable index based on the cable name.
   * @edev:	the extcon device that has the cable.
   * @cable_name:	cable name to be searched.
   *
   * Note that accessing a cable state based on cable_index is faster than
   * cable_name because using cable_name induces a loop with strncmp().
   * Thus, when get/set_cable_state is repeatedly used, using cable_index
   * is recommended.
   */
  int extcon_find_cable_index(struct extcon_dev *edev, const char *cable_name)
  {
  	int i;
  
  	if (edev->supported_cable) {
  		for (i = 0; edev->supported_cable[i]; i++) {
  			if (!strncmp(edev->supported_cable[i],
  				cable_name, CABLE_NAME_MAX))
  				return i;
  		}
  	}
  
  	return -EINVAL;
  }
  EXPORT_SYMBOL_GPL(extcon_find_cable_index);
  
  /**
   * extcon_get_cable_state_() - Get the status of a specific cable.
   * @edev:	the extcon device that has the cable.
   * @index:	cable index that can be retrieved by extcon_find_cable_index().
   */
  int extcon_get_cable_state_(struct extcon_dev *edev, int index)
  {
  	if (index < 0 || (edev->max_supported && edev->max_supported <= index))
  		return -EINVAL;
  
  	return !!(edev->state & (1 << index));
  }
  EXPORT_SYMBOL_GPL(extcon_get_cable_state_);
  
  /**
   * extcon_get_cable_state() - Get the status of a specific cable.
   * @edev:	the extcon device that has the cable.
   * @cable_name:	cable name.
   *
   * Note that this is slower than extcon_get_cable_state_.
   */
  int extcon_get_cable_state(struct extcon_dev *edev, const char *cable_name)
  {
  	return extcon_get_cable_state_(edev, extcon_find_cable_index
  						(edev, cable_name));
  }
  EXPORT_SYMBOL_GPL(extcon_get_cable_state);
  
  /**
   * extcon_set_cable_state_() - Set the status of a specific cable.
   * @edev:		the extcon device that has the cable.
   * @index:		cable index that can be retrieved by
   *			extcon_find_cable_index().
   * @cable_state:	the new cable status. The default semantics is
   *			true: attached / false: detached.
   */
  int extcon_set_cable_state_(struct extcon_dev *edev,
  			int index, bool cable_state)
  {
  	u32 state;
  
  	if (index < 0 || (edev->max_supported && edev->max_supported <= index))
  		return -EINVAL;
  
  	state = cable_state ? (1 << index) : 0;
  	return extcon_update_state(edev, 1 << index, state);
  }
  EXPORT_SYMBOL_GPL(extcon_set_cable_state_);
  
  /**
   * extcon_set_cable_state() - Set the status of a specific cable.
   * @edev:		the extcon device that has the cable.
   * @cable_name:		cable name.
   * @cable_state:	the new cable status. The default semantics is
   *			true: attached / false: detached.
   *
   * Note that this is slower than extcon_set_cable_state_.
   */
  int extcon_set_cable_state(struct extcon_dev *edev,
  			const char *cable_name, bool cable_state)
  {
  	return extcon_set_cable_state_(edev, extcon_find_cable_index
  					(edev, cable_name), cable_state);
  }
  EXPORT_SYMBOL_GPL(extcon_set_cable_state);
  
  /**
   * extcon_get_extcon_dev() - Get the extcon device instance from the name
   * @extcon_name:	The extcon name provided with extcon_dev_register()
   */
  struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
  {
  	struct extcon_dev *sd;
  
  	mutex_lock(&extcon_dev_list_lock);
  	list_for_each_entry(sd, &extcon_dev_list, entry) {
  		if (!strcmp(sd->name, extcon_name))
  			goto out;
  	}
  	sd = NULL;
  out:
  	mutex_unlock(&extcon_dev_list_lock);
  	return sd;
  }
  EXPORT_SYMBOL_GPL(extcon_get_extcon_dev);
  
  static int _call_per_cable(struct notifier_block *nb, unsigned long val,
  			   void *ptr)
  {
  	struct extcon_specific_cable_nb *obj = container_of(nb,
  			struct extcon_specific_cable_nb, internal_nb);
  	struct extcon_dev *edev = ptr;
  
  	if ((val & (1 << obj->cable_index)) !=
  	    (edev->state & (1 << obj->cable_index))) {
  		bool cable_state = true;
  
  		obj->previous_value = val;
  
  		if (val & (1 << obj->cable_index))
  			cable_state = false;
  
  		return obj->user_nb->notifier_call(obj->user_nb,
  				cable_state, ptr);
  	}
  
  	return NOTIFY_OK;
  }
  
  /**
   * extcon_register_interest() - Register a notifier for a state change of a
   *				specific cable, not an entier set of cables of a
   *				extcon device.
   * @obj:		an empty extcon_specific_cable_nb object to be returned.
   * @extcon_name:	the name of extcon device.
   *			if NULL, extcon_register_interest will register
   *			every cable with the target cable_name given.
   * @cable_name:		the target cable name.
   * @nb:			the notifier block to get notified.
   *
   * Provide an empty extcon_specific_cable_nb. extcon_register_interest() sets
   * the struct for you.
   *
   * extcon_register_interest is a helper function for those who want to get
   * notification for a single specific cable's status change. If a user wants
   * to get notification for any changes of all cables of a extcon device,
   * he/she should use the general extcon_register_notifier().
   *
   * Note that the second parameter given to the callback of nb (val) is
   * "old_state", not the current state. The current state can be retrieved
   * by looking at the third pameter (edev pointer)'s state value.
   */
  int extcon_register_interest(struct extcon_specific_cable_nb *obj,
  			     const char *extcon_name, const char *cable_name,
  			     struct notifier_block *nb)
  {
  	if (!obj || !cable_name || !nb)
  		return -EINVAL;
  
  	if (extcon_name) {
  		obj->edev = extcon_get_extcon_dev(extcon_name);
  		if (!obj->edev)
  			return -ENODEV;
  
  		obj->cable_index = extcon_find_cable_index(obj->edev,
  							  cable_name);
  		if (obj->cable_index < 0)
  			return obj->cable_index;
  
  		obj->user_nb = nb;
  
  		obj->internal_nb.notifier_call = _call_per_cable;
  
  		return raw_notifier_chain_register(&obj->edev->nh,
  						  &obj->internal_nb);
  	} else {
  		struct class_dev_iter iter;
  		struct extcon_dev *extd;
  		struct device *dev;
  
  		if (!extcon_class)
  			return -ENODEV;
  		class_dev_iter_init(&iter, extcon_class, NULL, NULL);
  		while ((dev = class_dev_iter_next(&iter))) {
  			extd = dev_get_drvdata(dev);
  
  			if (extcon_find_cable_index(extd, cable_name) < 0)
  				continue;
  
  			class_dev_iter_exit(&iter);
  			return extcon_register_interest(obj, extd->name,
  						cable_name, nb);
  		}
  
  		return -ENODEV;
  	}
  }
  EXPORT_SYMBOL_GPL(extcon_register_interest);
  
  /**
   * extcon_unregister_interest() - Unregister the notifier registered by
   *				  extcon_register_interest().
   * @obj:	the extcon_specific_cable_nb object returned by
   *		extcon_register_interest().
   */
  int extcon_unregister_interest(struct extcon_specific_cable_nb *obj)
  {
  	if (!obj)
  		return -EINVAL;
  
  	return raw_notifier_chain_unregister(&obj->edev->nh, &obj->internal_nb);
  }
  EXPORT_SYMBOL_GPL(extcon_unregister_interest);
  
  /**
   * extcon_register_notifier() - Register a notifiee to get notified by
   *				any attach status changes from the extcon.
   * @edev:	the extcon device.
   * @nb:		a notifier block to be registered.
   *
   * Note that the second parameter given to the callback of nb (val) is
   * "old_state", not the current state. The current state can be retrieved
   * by looking at the third pameter (edev pointer)'s state value.
   */
  int extcon_register_notifier(struct extcon_dev *edev,
  			struct notifier_block *nb)
  {
  	return raw_notifier_chain_register(&edev->nh, nb);
  }
  EXPORT_SYMBOL_GPL(extcon_register_notifier);
  
  /**
   * extcon_unregister_notifier() - Unregister a notifiee from the extcon device.
   * @edev:	the extcon device.
   * @nb:		a registered notifier block to be unregistered.
   */
  int extcon_unregister_notifier(struct extcon_dev *edev,
  			struct notifier_block *nb)
  {
  	return raw_notifier_chain_unregister(&edev->nh, nb);
  }
  EXPORT_SYMBOL_GPL(extcon_unregister_notifier);
  
  static struct attribute *extcon_attrs[] = {
  	&dev_attr_state.attr,
  	&dev_attr_name.attr,
  	NULL,
  };
  ATTRIBUTE_GROUPS(extcon);
  
  static int create_extcon_class(void)
  {
  	if (!extcon_class) {
  		extcon_class = class_create(THIS_MODULE, "extcon");
  		if (IS_ERR(extcon_class))
  			return PTR_ERR(extcon_class);
  		extcon_class->dev_groups = extcon_groups;
  
  #if defined(CONFIG_ANDROID)
  		switch_class = class_compat_register("switch");
  		if (WARN(!switch_class, "cannot allocate"))
  			return -ENOMEM;
  #endif /* CONFIG_ANDROID */
  	}
  
  	return 0;
  }
  
  static void extcon_dev_release(struct device *dev)
  {
  }
  
  static const char *muex_name = "mutually_exclusive";
  static void dummy_sysfs_dev_release(struct device *dev)
  {
  }
  
  /**
   * extcon_dev_register() - Register a new extcon device
   * @edev	: the new extcon device (should be allocated before calling)
   *
   * Among the members of edev struct, please set the "user initializing data"
   * in any case and set the "optional callbacks" if required. However, please
   * do not set the values of "internal data", which are initialized by
   * this function.
   */
  int extcon_dev_register(struct extcon_dev *edev)
  {
  	int ret, index = 0;
  
  	if (!extcon_class) {
  		ret = create_extcon_class();
  		if (ret < 0)
  			return ret;
  	}
  
  	if (edev->supported_cable) {
  		/* Get size of array */
  		for (index = 0; edev->supported_cable[index]; index++)
  			;
  		edev->max_supported = index;
  	} else {
  		edev->max_supported = 0;
  	}
  
  	if (index > SUPPORTED_CABLE_MAX) {
  		dev_err(&edev->dev, "extcon: maximum number of supported cables exceeded.
  ");
  		return -EINVAL;
  	}
  
  	edev->dev.class = extcon_class;
  	edev->dev.release = extcon_dev_release;
  
  	edev->name = edev->name ? edev->name : dev_name(edev->dev.parent);
  	if (IS_ERR_OR_NULL(edev->name)) {
  		dev_err(&edev->dev,
  			"extcon device name is null
  ");
  		return -EINVAL;
  	}
  	dev_set_name(&edev->dev, "%s", edev->name);
  
  	if (edev->max_supported) {
  		char buf[10];
  		char *str;
  		struct extcon_cable *cable;
  
  		edev->cables = kzalloc(sizeof(struct extcon_cable) *
  				       edev->max_supported, GFP_KERNEL);
  		if (!edev->cables) {
  			ret = -ENOMEM;
  			goto err_sysfs_alloc;
  		}
  		for (index = 0; index < edev->max_supported; index++) {
  			cable = &edev->cables[index];
  
  			snprintf(buf, 10, "cable.%d", index);
  			str = kzalloc(sizeof(char) * (strlen(buf) + 1),
  				      GFP_KERNEL);
  			if (!str) {
  				for (index--; index >= 0; index--) {
  					cable = &edev->cables[index];
  					kfree(cable->attr_g.name);
  				}
  				ret = -ENOMEM;
  
  				goto err_alloc_cables;
  			}
  			strcpy(str, buf);
  
  			cable->edev = edev;
  			cable->cable_index = index;
  			cable->attrs[0] = &cable->attr_name.attr;
  			cable->attrs[1] = &cable->attr_state.attr;
  			cable->attrs[2] = NULL;
  			cable->attr_g.name = str;
  			cable->attr_g.attrs = cable->attrs;
  
  			sysfs_attr_init(&cable->attr_name.attr);
  			cable->attr_name.attr.name = "name";
  			cable->attr_name.attr.mode = 0444;
  			cable->attr_name.show = cable_name_show;
  
  			sysfs_attr_init(&cable->attr_state.attr);
  			cable->attr_state.attr.name = "state";
  			cable->attr_state.attr.mode = 0444;
  			cable->attr_state.show = cable_state_show;
  		}
  	}
  
  	if (edev->max_supported && edev->mutually_exclusive) {
  		char buf[80];
  		char *name;
  
  		/* Count the size of mutually_exclusive array */
  		for (index = 0; edev->mutually_exclusive[index]; index++)
  			;
  
  		edev->attrs_muex = kzalloc(sizeof(struct attribute *) *
  					   (index + 1), GFP_KERNEL);
  		if (!edev->attrs_muex) {
  			ret = -ENOMEM;
  			goto err_muex;
  		}
  
  		edev->d_attrs_muex = kzalloc(sizeof(struct device_attribute) *
  					     index, GFP_KERNEL);
  		if (!edev->d_attrs_muex) {
  			ret = -ENOMEM;
  			kfree(edev->attrs_muex);
  			goto err_muex;
  		}
  
  		for (index = 0; edev->mutually_exclusive[index]; index++) {
  			sprintf(buf, "0x%x", edev->mutually_exclusive[index]);
  			name = kzalloc(sizeof(char) * (strlen(buf) + 1),
  				       GFP_KERNEL);
  			if (!name) {
  				for (index--; index >= 0; index--) {
  					kfree(edev->d_attrs_muex[index].attr.
  					      name);
  				}
  				kfree(edev->d_attrs_muex);
  				kfree(edev->attrs_muex);
  				ret = -ENOMEM;
  				goto err_muex;
  			}
  			strcpy(name, buf);
  			sysfs_attr_init(&edev->d_attrs_muex[index].attr);
  			edev->d_attrs_muex[index].attr.name = name;
  			edev->d_attrs_muex[index].attr.mode = 0000;
  			edev->attrs_muex[index] = &edev->d_attrs_muex[index]
  							.attr;
  		}
  		edev->attr_g_muex.name = muex_name;
  		edev->attr_g_muex.attrs = edev->attrs_muex;
  
  	}
  
  	if (edev->max_supported) {
  		edev->extcon_dev_type.groups =
  			kzalloc(sizeof(struct attribute_group *) *
  				(edev->max_supported + 2), GFP_KERNEL);
  		if (!edev->extcon_dev_type.groups) {
  			ret = -ENOMEM;
  			goto err_alloc_groups;
  		}
  
  		edev->extcon_dev_type.name = dev_name(&edev->dev);
  		edev->extcon_dev_type.release = dummy_sysfs_dev_release;
  
  		for (index = 0; index < edev->max_supported; index++)
  			edev->extcon_dev_type.groups[index] =
  				&edev->cables[index].attr_g;
  		if (edev->mutually_exclusive)
  			edev->extcon_dev_type.groups[index] =
  				&edev->attr_g_muex;
  
  		edev->dev.type = &edev->extcon_dev_type;
  	}
  
  	ret = device_register(&edev->dev);
  	if (ret) {
  		put_device(&edev->dev);
  		goto err_dev;
  	}
  #if defined(CONFIG_ANDROID)
  	if (switch_class)
  		ret = class_compat_create_link(switch_class, &edev->dev, NULL);
  #endif /* CONFIG_ANDROID */
  
  	spin_lock_init(&edev->lock);
  
  	RAW_INIT_NOTIFIER_HEAD(&edev->nh);
  
  	dev_set_drvdata(&edev->dev, edev);
  	edev->state = 0;
  
  	mutex_lock(&extcon_dev_list_lock);
  	list_add(&edev->entry, &extcon_dev_list);
  	mutex_unlock(&extcon_dev_list_lock);
  
  	return 0;
  
  err_dev:
  	if (edev->max_supported)
  		kfree(edev->extcon_dev_type.groups);
  err_alloc_groups:
  	if (edev->max_supported && edev->mutually_exclusive) {
  		for (index = 0; edev->mutually_exclusive[index]; index++)
  			kfree(edev->d_attrs_muex[index].attr.name);
  		kfree(edev->d_attrs_muex);
  		kfree(edev->attrs_muex);
  	}
  err_muex:
  	for (index = 0; index < edev->max_supported; index++)
  		kfree(edev->cables[index].attr_g.name);
  err_alloc_cables:
  	if (edev->max_supported)
  		kfree(edev->cables);
  err_sysfs_alloc:
  	return ret;
  }
  EXPORT_SYMBOL_GPL(extcon_dev_register);
  
  /**
   * extcon_dev_unregister() - Unregister the extcon device.
   * @edev:	the extcon device instance to be unregistered.
   *
   * Note that this does not call kfree(edev) because edev was not allocated
   * by this class.
   */
  void extcon_dev_unregister(struct extcon_dev *edev)
  {
  	int index;
  
  	mutex_lock(&extcon_dev_list_lock);
  	list_del(&edev->entry);
  	mutex_unlock(&extcon_dev_list_lock);
  
  	if (IS_ERR_OR_NULL(get_device(&edev->dev))) {
  		dev_err(&edev->dev, "Failed to unregister extcon_dev (%s)
  ",
  				dev_name(&edev->dev));
  		return;
  	}
  
  	device_unregister(&edev->dev);
  
  	if (edev->mutually_exclusive && edev->max_supported) {
  		for (index = 0; edev->mutually_exclusive[index];
  				index++)
  			kfree(edev->d_attrs_muex[index].attr.name);
  		kfree(edev->d_attrs_muex);
  		kfree(edev->attrs_muex);
  	}
  
  	for (index = 0; index < edev->max_supported; index++)
  		kfree(edev->cables[index].attr_g.name);
  
  	if (edev->max_supported) {
  		kfree(edev->extcon_dev_type.groups);
  		kfree(edev->cables);
  	}
  
  #if defined(CONFIG_ANDROID)
  	if (switch_class)
  		class_compat_remove_link(switch_class, &edev->dev, NULL);
  #endif
  	put_device(&edev->dev);
  }
  EXPORT_SYMBOL_GPL(extcon_dev_unregister);
  
  static int __init extcon_class_init(void)
  {
  	return create_extcon_class();
  }
  module_init(extcon_class_init);
  
  static void __exit extcon_class_exit(void)
  {
  #if defined(CONFIG_ANDROID)
  	class_compat_unregister(switch_class);
  #endif
  	class_destroy(extcon_class);
  }
  module_exit(extcon_class_exit);
  
  MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
  MODULE_AUTHOR("Donggeun Kim <dg77.kim@samsung.com>");
  MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
  MODULE_DESCRIPTION("External connector (extcon) class driver");
  MODULE_LICENSE("GPL");