/*

   *  drivers/extcon/extcon.c - External Connector (extcon) framework.

   *
   *  External connector (extcon) class driver
   *

   * Copyright (C) 2015 Samsung Electronics
   * Author: Chanwoo Choi <cw00.choi@samsung.com>
   *

   * 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/of.h>

  #include <linux/slab.h>

  #include <linux/sysfs.h>

  #define SUPPORTED_CABLE_MAX	32
  #define CABLE_NAME_MAX		30

  struct __extcon_info {
  	unsigned int type;
  	unsigned int id;
  	const char *name;
  
  } extcon_info[] = {
  	[EXTCON_NONE] = {
  		.type = EXTCON_TYPE_MISC,
  		.id = EXTCON_NONE,
  		.name = "NONE",
  	},

  	/* USB external connector */

  	[EXTCON_USB] = {
  		.type = EXTCON_TYPE_USB,
  		.id = EXTCON_USB,
  		.name = "USB",
  	},
  	[EXTCON_USB_HOST] = {
  		.type = EXTCON_TYPE_USB,
  		.id = EXTCON_USB_HOST,
  		.name = "USB_HOST",
  	},

  	/* Charging external connector */

  	[EXTCON_CHG_USB_SDP] = {
  		.type = EXTCON_TYPE_CHG | EXTCON_TYPE_USB,
  		.id = EXTCON_CHG_USB_SDP,
  		.name = "SDP",
  	},
  	[EXTCON_CHG_USB_DCP] = {
  		.type = EXTCON_TYPE_CHG | EXTCON_TYPE_USB,
  		.id = EXTCON_CHG_USB_DCP,
  		.name = "DCP",
  	},
  	[EXTCON_CHG_USB_CDP] = {
  		.type = EXTCON_TYPE_CHG | EXTCON_TYPE_USB,
  		.id = EXTCON_CHG_USB_CDP,
  		.name = "CDP",
  	},
  	[EXTCON_CHG_USB_ACA] = {
  		.type = EXTCON_TYPE_CHG | EXTCON_TYPE_USB,
  		.id = EXTCON_CHG_USB_ACA,
  		.name = "ACA",
  	},
  	[EXTCON_CHG_USB_FAST] = {
  		.type = EXTCON_TYPE_CHG | EXTCON_TYPE_USB,
  		.id = EXTCON_CHG_USB_FAST,
  		.name = "FAST-CHARGER",
  	},
  	[EXTCON_CHG_USB_SLOW] = {
  		.type = EXTCON_TYPE_CHG | EXTCON_TYPE_USB,
  		.id = EXTCON_CHG_USB_SLOW,
  		.name = "SLOW-CHARGER",
  	},

  	[EXTCON_CHG_WPT] = {
  		.type = EXTCON_TYPE_CHG,
  		.id = EXTCON_CHG_WPT,
  		.name = "WPT",
  	},

  	/* Jack external connector */

  	[EXTCON_JACK_MICROPHONE] = {
  		.type = EXTCON_TYPE_JACK,
  		.id = EXTCON_JACK_MICROPHONE,
  		.name = "MICROPHONE",
  	},
  	[EXTCON_JACK_HEADPHONE] = {
  		.type = EXTCON_TYPE_JACK,
  		.id = EXTCON_JACK_HEADPHONE,
  		.name = "HEADPHONE",
  	},
  	[EXTCON_JACK_LINE_IN] = {
  		.type = EXTCON_TYPE_JACK,
  		.id = EXTCON_JACK_LINE_IN,
  		.name = "LINE-IN",
  	},
  	[EXTCON_JACK_LINE_OUT] = {
  		.type = EXTCON_TYPE_JACK,
  		.id = EXTCON_JACK_LINE_OUT,
  		.name = "LINE-OUT",
  	},
  	[EXTCON_JACK_VIDEO_IN] = {
  		.type = EXTCON_TYPE_JACK,
  		.id = EXTCON_JACK_VIDEO_IN,
  		.name = "VIDEO-IN",
  	},
  	[EXTCON_JACK_VIDEO_OUT] = {
  		.type = EXTCON_TYPE_JACK,
  		.id = EXTCON_JACK_VIDEO_OUT,
  		.name = "VIDEO-OUT",
  	},
  	[EXTCON_JACK_SPDIF_IN] = {
  		.type = EXTCON_TYPE_JACK,
  		.id = EXTCON_JACK_SPDIF_IN,
  		.name = "SPDIF-IN",
  	},
  	[EXTCON_JACK_SPDIF_OUT] = {
  		.type = EXTCON_TYPE_JACK,
  		.id = EXTCON_JACK_SPDIF_OUT,
  		.name = "SPDIF-OUT",
  	},

  	/* Display external connector */

  	[EXTCON_DISP_HDMI] = {
  		.type = EXTCON_TYPE_DISP,
  		.id = EXTCON_DISP_HDMI,
  		.name = "HDMI",
  	},
  	[EXTCON_DISP_MHL] = {
  		.type = EXTCON_TYPE_DISP,
  		.id = EXTCON_DISP_MHL,
  		.name = "MHL",
  	},
  	[EXTCON_DISP_DVI] = {
  		.type = EXTCON_TYPE_DISP,
  		.id = EXTCON_DISP_DVI,
  		.name = "DVI",
  	},
  	[EXTCON_DISP_VGA] = {
  		.type = EXTCON_TYPE_DISP,
  		.id = EXTCON_DISP_VGA,
  		.name = "VGA",
  	},

  	[EXTCON_DISP_DP] = {
  		.type = EXTCON_TYPE_DISP | EXTCON_TYPE_USB,
  		.id = EXTCON_DISP_DP,
  		.name = "DP",
  	},

  	[EXTCON_DISP_HMD] = {
  		.type = EXTCON_TYPE_DISP | EXTCON_TYPE_USB,
  		.id = EXTCON_DISP_HMD,
  		.name = "HMD",
  	},

  	/* Miscellaneous external connector */

  	[EXTCON_DOCK] = {
  		.type = EXTCON_TYPE_MISC,
  		.id = EXTCON_DOCK,
  		.name = "DOCK",
  	},
  	[EXTCON_JIG] = {
  		.type = EXTCON_TYPE_MISC,
  		.id = EXTCON_JIG,
  		.name = "JIG",
  	},
  	[EXTCON_MECHANICAL] = {
  		.type = EXTCON_TYPE_MISC,
  		.id = EXTCON_MECHANICAL,
  		.name = "MECHANICAL",
  	},
  
  	{ /* sentinel */ }

  };

  /**
   * struct extcon_cable - An internal data for each cable of extcon device.
   * @edev:		The extcon device
   * @cable_index:	Index of this cable in the edev
   * @attr_g:		Attribute group for the cable
   * @attr_name:		"name" sysfs entry
   * @attr_state:		"state" sysfs entry
   * @attrs:		Array pointing to attr_name and attr_state for attr_g
   */
  struct extcon_cable {
  	struct extcon_dev *edev;
  	int cable_index;
  
  	struct attribute_group attr_g;
  	struct device_attribute attr_name;
  	struct device_attribute attr_state;
  
  	struct attribute *attrs[3]; /* to be fed to attr_g.attrs */

  
  	union extcon_property_value usb_propval[EXTCON_PROP_USB_CNT];
  	union extcon_property_value chg_propval[EXTCON_PROP_CHG_CNT];
  	union extcon_property_value jack_propval[EXTCON_PROP_JACK_CNT];
  	union extcon_property_value disp_propval[EXTCON_PROP_DISP_CNT];

  
  	unsigned long usb_bits[BITS_TO_LONGS(EXTCON_PROP_USB_CNT)];
  	unsigned long chg_bits[BITS_TO_LONGS(EXTCON_PROP_CHG_CNT)];
  	unsigned long jack_bits[BITS_TO_LONGS(EXTCON_PROP_JACK_CNT)];
  	unsigned long disp_bits[BITS_TO_LONGS(EXTCON_PROP_DISP_CNT)];

  };

  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 int find_cable_index_by_id(struct extcon_dev *edev, const unsigned int id)

  {
  	int i;
  
  	/* Find the the index of extcon cable in edev->supported_cable */
  	for (i = 0; i < edev->max_supported; i++) {
  		if (edev->supported_cable[i] == id)
  			return i;
  	}
  
  	return -EINVAL;
  }

  static int get_extcon_type(unsigned int prop)
  {
  	switch (prop) {
  	case EXTCON_PROP_USB_MIN ... EXTCON_PROP_USB_MAX:
  		return EXTCON_TYPE_USB;
  	case EXTCON_PROP_CHG_MIN ... EXTCON_PROP_CHG_MAX:
  		return EXTCON_TYPE_CHG;
  	case EXTCON_PROP_JACK_MIN ... EXTCON_PROP_JACK_MAX:
  		return EXTCON_TYPE_JACK;
  	case EXTCON_PROP_DISP_MIN ... EXTCON_PROP_DISP_MAX:
  		return EXTCON_TYPE_DISP;
  	default:
  		return -EINVAL;
  	}
  }
  
  static bool is_extcon_attached(struct extcon_dev *edev, unsigned int index)
  {
  	return !!(edev->state & BIT(index));
  }

  static bool is_extcon_changed(struct extcon_dev *edev, int index,
  				bool new_state)

  {

  	int state = !!(edev->state & BIT(index));
  	return (state != new_state);

  }

  static bool is_extcon_property_supported(unsigned int id, unsigned int prop)
  {
  	int type;
  
  	/* Check whether the property is supported or not. */
  	type = get_extcon_type(prop);
  	if (type < 0)
  		return false;
  
  	/* Check whether a specific extcon id supports the property or not. */
  	return !!(extcon_info[id].type & type);
  }

  static int is_extcon_property_capability(struct extcon_dev *edev,
  				unsigned int id, int index,unsigned int prop)
  {
  	struct extcon_cable *cable;
  	int type, ret;
  
  	/* Check whether the property is supported or not. */
  	type = get_extcon_type(prop);
  	if (type < 0)
  		return type;
  
  	cable = &edev->cables[index];
  
  	switch (type) {
  	case EXTCON_TYPE_USB:
  		ret = test_bit(prop - EXTCON_PROP_USB_MIN, cable->usb_bits);
  		break;
  	case EXTCON_TYPE_CHG:
  		ret = test_bit(prop - EXTCON_PROP_CHG_MIN, cable->chg_bits);
  		break;
  	case EXTCON_TYPE_JACK:
  		ret = test_bit(prop - EXTCON_PROP_JACK_MIN, cable->jack_bits);
  		break;
  	case EXTCON_TYPE_DISP:
  		ret = test_bit(prop - EXTCON_PROP_DISP_MIN, cable->disp_bits);
  		break;
  	default:
  		ret = -EINVAL;
  	}
  
  	return ret;
  }

  static void init_property(struct extcon_dev *edev, unsigned int id, int index)
  {
  	unsigned int type = extcon_info[id].type;
  	struct extcon_cable *cable = &edev->cables[index];
  
  	if (EXTCON_TYPE_USB & type)
  		memset(cable->usb_propval, 0, sizeof(cable->usb_propval));
  	if (EXTCON_TYPE_CHG & type)
  		memset(cable->chg_propval, 0, sizeof(cable->chg_propval));
  	if (EXTCON_TYPE_JACK & type)
  		memset(cable->jack_propval, 0, sizeof(cable->jack_propval));
  	if (EXTCON_TYPE_DISP & type)
  		memset(cable->disp_propval, 0, sizeof(cable->disp_propval));
  }

  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->max_supported == 0)
  		return sprintf(buf, "%u
  ", edev->state);

  	for (i = 0; i < edev->max_supported; i++) {

  		count += sprintf(buf + count, "%s=%d
  ",

  				extcon_info[edev->supported_cable[i]].name,

  				 !!(edev->state & (1 << i)));
  	}
  
  	return count;
  }

  static DEVICE_ATTR_RO(state);

  
  static ssize_t name_show(struct device *dev, struct device_attribute *attr,
  		char *buf)
  {

  	struct extcon_dev *edev = dev_get_drvdata(dev);

  	return sprintf(buf, "%s
  ", edev->name);

  }

  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);

  	int i = cable->cable_index;

  
  	return sprintf(buf, "%s
  ",

  			extcon_info[cable->edev->supported_cable[i]].name);

  }
  
  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);

  	int i = cable->cable_index;

  	return sprintf(buf, "%d
  ",

  		extcon_get_state(cable->edev, cable->edev->supported_cable[i]));

  }

  /**

   * extcon_sync()	- Synchronize the states for both the attached/detached
   * @edev:		the extcon device that has the cable.

   *

   * This function send a notification to synchronize the all states of a
   * specific external connector

   */

  int extcon_sync(struct extcon_dev *edev, unsigned int id)

  {
  	char name_buf[120];
  	char state_buf[120];
  	char *prop_buf;
  	char *envp[3];
  	int env_offset = 0;
  	int length;

  	int index;

  	int state;

  	unsigned long flags;

  	if (!edev)
  		return -EINVAL;

  	index = find_cable_index_by_id(edev, id);
  	if (index < 0)
  		return index;

  	spin_lock_irqsave(&edev->lock, flags);

  	state = !!(edev->state & BIT(index));
  	raw_notifier_call_chain(&edev->nh[index], state, edev);
  
  	/* This could be in interrupt handler */
  	prop_buf = (char *)get_zeroed_page(GFP_ATOMIC);
  	if (!prop_buf) {
  		/* 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);

  		return -ENOMEM;

  	}
  
  	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);

  
  	return 0;

  }

  EXPORT_SYMBOL_GPL(extcon_sync);

  /**

   * extcon_get_state() - Get the state of a external connector.

   * @edev:	the extcon device that has the cable.

   * @id:		the unique id of each external connector in extcon enumeration.

   */

  int extcon_get_state(struct extcon_dev *edev, const unsigned int id)

  {

  	int index, state;
  	unsigned long flags;

  	if (!edev)
  		return -EINVAL;

  	index = find_cable_index_by_id(edev, id);
  	if (index < 0)
  		return index;

  	spin_lock_irqsave(&edev->lock, flags);
  	state = is_extcon_attached(edev, index);
  	spin_unlock_irqrestore(&edev->lock, flags);

  	return state;

  }

  EXPORT_SYMBOL_GPL(extcon_get_state);

  
  /**

   * extcon_set_state() - Set the state of a external connector.

   *			without a notification.

   * @edev:		the extcon device that has the cable.

   * @id:			the unique id of each external connector
   *			in extcon enumeration.
   * @state:		the new cable status. The default semantics is

   *			true: attached / false: detached.

   *
   * This function only set the state of a external connector without
   * a notification. To synchronize the data of a external connector,
   * use extcon_set_state_sync() and extcon_sync().

   */

  int extcon_set_state(struct extcon_dev *edev, unsigned int id,

  				bool cable_state)

  {

  	unsigned long flags;
  	int index, ret = 0;

  	if (!edev)
  		return -EINVAL;

  	index = find_cable_index_by_id(edev, id);
  	if (index < 0)
  		return index;

  	spin_lock_irqsave(&edev->lock, flags);
  
  	/* Check whether the external connector's state is changed. */
  	if (!is_extcon_changed(edev, index, cable_state))
  		goto out;
  
  	if (check_mutually_exclusive(edev,
  		(edev->state & ~BIT(index)) | (cable_state & BIT(index)))) {
  		ret = -EPERM;
  		goto out;
  	}

  	/*
  	 * Initialize the value of extcon property before setting
  	 * the detached state for an external connector.
  	 */
  	if (!cable_state)
  		init_property(edev, id, index);

  	/* Update the state for a external connector. */
  	if (cable_state)
  		edev->state |= BIT(index);
  	else
  		edev->state &= ~(BIT(index));
  out:
  	spin_unlock_irqrestore(&edev->lock, flags);
  
  	return ret;

  }

  EXPORT_SYMBOL_GPL(extcon_set_state);

  
  /**

   * extcon_set_state_sync() - Set the state of a external connector
   *			with a notification.
   * @edev:		the extcon device that has the cable.
   * @id:			the unique id of each external connector
   *			in extcon enumeration.
   * @state:		the new cable status. The default semantics is
   *			true: attached / false: detached.
   *
   * This function set the state of external connector and synchronize the data
   * by usning a notification.
   */
  int extcon_set_state_sync(struct extcon_dev *edev, unsigned int id,
  				bool cable_state)
  {
  	int ret, index;
  	unsigned long flags;
  
  	index = find_cable_index_by_id(edev, id);
  	if (index < 0)
  		return index;
  
  	/* Check whether the external connector's state is changed. */
  	spin_lock_irqsave(&edev->lock, flags);
  	ret = is_extcon_changed(edev, index, cable_state);
  	spin_unlock_irqrestore(&edev->lock, flags);
  	if (!ret)
  		return 0;
  
  	ret = extcon_set_state(edev, id, cable_state);
  	if (ret < 0)
  		return ret;
  
  	return extcon_sync(edev, id);
  }
  EXPORT_SYMBOL_GPL(extcon_set_state_sync);
  
  /**

   * extcon_get_property() - Get the property value of a specific cable.
   * @edev:		the extcon device that has the cable.
   * @id:			the unique id of each external connector
   *			in extcon enumeration.
   * @prop:		the property id among enum extcon_property.
   * @prop_val:		the pointer which store the value of property.
   *
   * When getting the property value of external connector, the external connector
   * should be attached. If detached state, function just return 0 without
   * property value. Also, the each property should be included in the list of
   * supported properties according to the type of external connectors.
   *
   * Returns 0 if success or error number if fail
   */
  int extcon_get_property(struct extcon_dev *edev, unsigned int id,
  				unsigned int prop,
  				union extcon_property_value *prop_val)
  {
  	struct extcon_cable *cable;
  	unsigned long flags;
  	int index, ret = 0;
  
  	*prop_val = (union extcon_property_value)(0);
  
  	if (!edev)
  		return -EINVAL;
  
  	/* Check whether the property is supported or not */
  	if (!is_extcon_property_supported(id, prop))
  		return -EINVAL;
  
  	/* Find the cable index of external connector by using id */
  	index = find_cable_index_by_id(edev, id);
  	if (index < 0)
  		return index;
  
  	spin_lock_irqsave(&edev->lock, flags);

  	/* Check whether the property is available or not. */
  	if (!is_extcon_property_capability(edev, id, index, prop)) {
  		spin_unlock_irqrestore(&edev->lock, flags);
  		return -EPERM;
  	}

  	/*
  	 * Check whether the external connector is attached.
  	 * If external connector is detached, the user can not
  	 * get the property value.
  	 */
  	if (!is_extcon_attached(edev, index)) {
  		spin_unlock_irqrestore(&edev->lock, flags);
  		return 0;
  	}
  
  	cable = &edev->cables[index];
  
  	/* Get the property value according to extcon type */
  	switch (prop) {
  	case EXTCON_PROP_USB_MIN ... EXTCON_PROP_USB_MAX:
  		*prop_val = cable->usb_propval[prop - EXTCON_PROP_USB_MIN];
  		break;
  	case EXTCON_PROP_CHG_MIN ... EXTCON_PROP_CHG_MAX:
  		*prop_val = cable->chg_propval[prop - EXTCON_PROP_CHG_MIN];
  		break;
  	case EXTCON_PROP_JACK_MIN ... EXTCON_PROP_JACK_MAX:
  		*prop_val = cable->jack_propval[prop - EXTCON_PROP_JACK_MIN];
  		break;
  	case EXTCON_PROP_DISP_MIN ... EXTCON_PROP_DISP_MAX:
  		*prop_val = cable->disp_propval[prop - EXTCON_PROP_DISP_MIN];
  		break;
  	default:
  		ret = -EINVAL;
  		break;
  	}
  
  	spin_unlock_irqrestore(&edev->lock, flags);
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(extcon_get_property);
  
  /**
   * extcon_set_property() - Set the property value of a specific cable.
   * @edev:		the extcon device that has the cable.
   * @id:			the unique id of each external connector
   *			in extcon enumeration.
   * @prop:		the property id among enum extcon_property.
   * @prop_val:		the pointer including the new value of property.
   *
   * The each property should be included in the list of supported properties
   * according to the type of external connectors.
   *
   * Returns 0 if success or error number if fail
   */
  int extcon_set_property(struct extcon_dev *edev, unsigned int id,
  				unsigned int prop,
  				union extcon_property_value prop_val)
  {
  	struct extcon_cable *cable;
  	unsigned long flags;
  	int index, ret = 0;
  
  	if (!edev)
  		return -EINVAL;
  
  	/* Check whether the property is supported or not */
  	if (!is_extcon_property_supported(id, prop))
  		return -EINVAL;
  
  	/* Find the cable index of external connector by using id */
  	index = find_cable_index_by_id(edev, id);
  	if (index < 0)
  		return index;
  
  	spin_lock_irqsave(&edev->lock, flags);

  	/* Check whether the property is available or not. */
  	if (!is_extcon_property_capability(edev, id, index, prop)) {
  		spin_unlock_irqrestore(&edev->lock, flags);
  		return -EPERM;
  	}

  	cable = &edev->cables[index];
  
  	/* Set the property value according to extcon type */
  	switch (prop) {
  	case EXTCON_PROP_USB_MIN ... EXTCON_PROP_USB_MAX:
  		cable->usb_propval[prop - EXTCON_PROP_USB_MIN] = prop_val;
  		break;
  	case EXTCON_PROP_CHG_MIN ... EXTCON_PROP_CHG_MAX:
  		cable->chg_propval[prop - EXTCON_PROP_CHG_MIN] = prop_val;
  		break;
  	case EXTCON_PROP_JACK_MIN ... EXTCON_PROP_JACK_MAX:
  		cable->jack_propval[prop - EXTCON_PROP_JACK_MIN] = prop_val;
  		break;
  	case EXTCON_PROP_DISP_MIN ... EXTCON_PROP_DISP_MAX:
  		cable->disp_propval[prop - EXTCON_PROP_DISP_MIN] = prop_val;
  		break;
  	default:
  		ret = -EINVAL;
  		break;
  	}
  
  	spin_unlock_irqrestore(&edev->lock, flags);
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(extcon_set_property);
  
  /**

   * extcon_set_property_sync() - Set the property value of a specific cable
  			with a notification.
   * @prop_val:		the pointer including the new value of property.
   *
   * When setting the property value of external connector, the external connector
   * should be attached. The each property should be included in the list of
   * supported properties according to the type of external connectors.
   *
   * Returns 0 if success or error number if fail
   */
  int extcon_set_property_sync(struct extcon_dev *edev, unsigned int id,
  				unsigned int prop,
  				union extcon_property_value prop_val)
  {
  	int ret;
  
  	ret = extcon_set_property(edev, id, prop, prop_val);
  	if (ret < 0)
  		return ret;
  
  	return extcon_sync(edev, id);
  }
  EXPORT_SYMBOL_GPL(extcon_set_property_sync);
  
  /**

   * extcon_get_property_capability() - Get the capability of property
   *			of an external connector.
   * @edev:		the extcon device that has the cable.
   * @id:			the unique id of each external connector
   *			in extcon enumeration.
   * @prop:		the property id among enum extcon_property.
   *
   * Returns 1 if the property is available or 0 if not available.
   */
  int extcon_get_property_capability(struct extcon_dev *edev, unsigned int id,
  					unsigned int prop)
  {
  	int index;
  
  	if (!edev)
  		return -EINVAL;
  
  	/* Check whether the property is supported or not */
  	if (!is_extcon_property_supported(id, prop))
  		return -EINVAL;
  
  	/* Find the cable index of external connector by using id */
  	index = find_cable_index_by_id(edev, id);
  	if (index < 0)
  		return index;
  
  	return is_extcon_property_capability(edev, id, index, prop);
  }
  EXPORT_SYMBOL_GPL(extcon_get_property_capability);
  
  /**
   * extcon_set_property_capability() - Set the capability of a property
   *			of an external connector.
   * @edev:		the extcon device that has the cable.
   * @id:			the unique id of each external connector
   *			in extcon enumeration.
   * @prop:		the property id among enum extcon_property.
   *
   * This function set the capability of a property for an external connector
   * to mark the bit in capability bitmap which mean the available state of
   * a property.
   *
   * Returns 0 if success or error number if fail
   */
  int extcon_set_property_capability(struct extcon_dev *edev, unsigned int id,
  					unsigned int prop)
  {
  	struct extcon_cable *cable;
  	int index, type, ret = 0;
  
  	if (!edev)
  		return -EINVAL;
  
  	/* Check whether the property is supported or not. */
  	if (!is_extcon_property_supported(id, prop))
  		return -EINVAL;
  
  	/* Find the cable index of external connector by using id. */
  	index = find_cable_index_by_id(edev, id);
  	if (index < 0)
  		return index;
  
  	type = get_extcon_type(prop);
  	if (type < 0)
  		return type;
  
  	cable = &edev->cables[index];
  
  	switch (type) {
  	case EXTCON_TYPE_USB:
  		__set_bit(prop - EXTCON_PROP_USB_MIN, cable->usb_bits);
  		break;
  	case EXTCON_TYPE_CHG:
  		__set_bit(prop - EXTCON_PROP_CHG_MIN, cable->chg_bits);
  		break;
  	case EXTCON_TYPE_JACK:
  		__set_bit(prop - EXTCON_PROP_JACK_MIN, cable->jack_bits);
  		break;
  	case EXTCON_TYPE_DISP:
  		__set_bit(prop - EXTCON_PROP_DISP_MIN, cable->disp_bits);
  		break;
  	default:
  		ret = -EINVAL;
  	}
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(extcon_set_property_capability);
  
  /**

   * 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;

  	if (!extcon_name)
  		return ERR_PTR(-EINVAL);

  	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);

  /**

   * extcon_register_notifier() - Register a notifiee to get notified by

   *				any attach status changes from the extcon.

   * @edev:	the extcon device that has the external connecotr.
   * @id:		the unique id of each external connector in extcon enumeration.

   * @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, unsigned int id,

  			     struct notifier_block *nb)

  {

  	unsigned long flags;

  	int ret, idx = -EINVAL;

  	if (!nb)

  		return -EINVAL;

  	if (edev) {
  		idx = find_cable_index_by_id(edev, id);

  		if (idx < 0)
  			return idx;

  		spin_lock_irqsave(&edev->lock, flags);
  		ret = raw_notifier_chain_register(&edev->nh[idx], nb);
  		spin_unlock_irqrestore(&edev->lock, flags);
  	} else {
  		struct extcon_dev *extd;
  
  		mutex_lock(&extcon_dev_list_lock);
  		list_for_each_entry(extd, &extcon_dev_list, entry) {
  			idx = find_cable_index_by_id(extd, id);
  			if (idx >= 0)
  				break;
  		}
  		mutex_unlock(&extcon_dev_list_lock);
  
  		if (idx >= 0) {
  			edev = extd;
  			return extcon_register_notifier(extd, id, nb);
  		} else {
  			ret = -ENODEV;
  		}
  	}

  
  	return ret;

  }
  EXPORT_SYMBOL_GPL(extcon_register_notifier);
  
  /**

   * extcon_unregister_notifier() - Unregister a notifiee from the extcon device.

   * @edev:	the extcon device that has the external connecotr.
   * @id:		the unique id of each external connector in extcon enumeration.
   * @nb:		a notifier block to be registered.

   */

  int extcon_unregister_notifier(struct extcon_dev *edev, unsigned int id,

  				struct notifier_block *nb)

  {

  	unsigned long flags;

  	int ret, idx;

  	if (!edev || !nb)
  		return -EINVAL;

  	idx = find_cable_index_by_id(edev, id);

  	if (idx < 0)
  		return idx;

  
  	spin_lock_irqsave(&edev->lock, flags);

  	ret = raw_notifier_chain_unregister(&edev->nh[idx], nb);

  	spin_unlock_irqrestore(&edev->lock, flags);
  
  	return ret;

  }
  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_allocate() - Allocate the memory of extcon device.

   * @supported_cable:	Array of supported extcon ending with EXTCON_NONE.

   *			If supported_cable is NULL, cable name related APIs
   *			are disabled.
   *
   * This function allocates the memory for extcon device without allocating
   * memory in each extcon provider driver and initialize default setting for
   * extcon device.
   *
   * Return the pointer of extcon device if success or ERR_PTR(err) if fail
   */

  struct extcon_dev *extcon_dev_allocate(const unsigned int *supported_cable)

  {
  	struct extcon_dev *edev;

  	if (!supported_cable)
  		return ERR_PTR(-EINVAL);

  	edev = kzalloc(sizeof(*edev), GFP_KERNEL);
  	if (!edev)
  		return ERR_PTR(-ENOMEM);
  
  	edev->max_supported = 0;
  	edev->supported_cable = supported_cable;
  
  	return edev;
  }
  
  /*
   * extcon_dev_free() - Free the memory of extcon device.
   * @edev:	the extcon device to free
   */
  void extcon_dev_free(struct extcon_dev *edev)
  {
  	kfree(edev);
  }
  EXPORT_SYMBOL_GPL(extcon_dev_free);

  /**
   * 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;

  	static atomic_t edev_no = ATOMIC_INIT(-1);

  
  	if (!extcon_class) {
  		ret = create_extcon_class();
  		if (ret < 0)
  			return ret;
  	}

  	if (!edev || !edev->supported_cable)

  		return -EINVAL;
  
  	for (; edev->supported_cable[index] != EXTCON_NONE; index++);

  	edev->max_supported = index;

  	if (index > SUPPORTED_CABLE_MAX) {

  		dev_err(&edev->dev,
  			"exceed the maximum number of supported cables
  ");

  		return -EINVAL;
  	}

  	edev->dev.class = extcon_class;
  	edev->dev.release = extcon_dev_release;

  	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, "extcon%lu",
  			(unsigned long)atomic_inc_return(&edev_no));

  
  	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);

  	edev->nh = devm_kzalloc(&edev->dev,
  			sizeof(*edev->nh) * edev->max_supported, GFP_KERNEL);
  	if (!edev->nh) {
  		ret = -ENOMEM;
  		goto err_dev;
  	}
  
  	for (index = 0; index < edev->max_supported; index++)
  		RAW_INIT_NOTIFIER_HEAD(&edev->nh[index]);

  	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;

  	if (!edev)
  		return;

  	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);

  #ifdef CONFIG_OF
  /*
   * extcon_get_edev_by_phandle - Get the extcon device from devicetree
   * @dev - instance to the given device
   * @index - index into list of extcon_dev
   *
   * return the instance of extcon device
   */
  struct extcon_dev *extcon_get_edev_by_phandle(struct device *dev, int index)
  {
  	struct device_node *node;
  	struct extcon_dev *edev;

  	if (!dev)
  		return ERR_PTR(-EINVAL);

  	if (!dev->of_node) {

  		dev_dbg(dev, "device does not have a device node entry
  ");

  		return ERR_PTR(-EINVAL);
  	}
  
  	node = of_parse_phandle(dev->of_node, "extcon", index);
  	if (!node) {

  		dev_dbg(dev, "failed to get phandle in %s node
  ",

  			dev->of_node->full_name);
  		return ERR_PTR(-ENODEV);
  	}

  	mutex_lock(&extcon_dev_list_lock);
  	list_for_each_entry(edev, &extcon_dev_list, entry) {
  		if (edev->dev.parent && edev->dev.parent->of_node == node) {
  			mutex_unlock(&extcon_dev_list_lock);

  			of_node_put(node);

  			return edev;
  		}

  	}

  	mutex_unlock(&extcon_dev_list_lock);

  	of_node_put(node);

  	return ERR_PTR(-EPROBE_DEFER);

  }
  #else
  struct extcon_dev *extcon_get_edev_by_phandle(struct device *dev, int index)
  {
  	return ERR_PTR(-ENOSYS);
  }
  #endif /* CONFIG_OF */
  EXPORT_SYMBOL_GPL(extcon_get_edev_by_phandle);

  /**
   * extcon_get_edev_name() - Get the name of the extcon device.
   * @edev:	the extcon device
   */
  const char *extcon_get_edev_name(struct extcon_dev *edev)
  {
  	return !edev ? NULL : edev->name;
  }

  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("Chanwoo Choi <cw00.choi@samsung.com>");

  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");