text: /*
   *  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 switch class driver
   * 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.
   *
  */
  
  #ifndef __LINUX_EXTCON_H__
  #define __LINUX_EXTCON_H__
  
  #include <linux/notifier.h>
  
  #define SUPPORTED_CABLE_MAX	32
  #define CABLE_NAME_MAX		30
  
  /*
   * The standard cable name is to help support general notifier
   * and notifee device drivers to share the common names.
   * Please use standard cable names unless your notifier device has
   * a very unique and abnormal cable or
   * the cable type is supposed to be used with only one unique
   * pair of notifier/notifee devices.
   *
   * Please add any other "standard" cables used with extcon dev.
   *
   * You may add a dot and number to specify version or specification
   * of the specific cable if it is required. (e.g., "Fast-charger.18"
   * and "Fast-charger.10" for 1.8A and 1.0A chargers)
   * However, the notifee and notifier should be able to handle such
   * string and if the notifee can negotiate the protocol or idenify,
   * you don't need such convention. This convention is helpful when
   * notifier can distinguish but notifiee cannot.
   */
  enum extcon_cable_name {
  	EXTCON_USB = 0,
  	EXTCON_USB_HOST,
  	EXTCON_TA, /* Travel Adaptor */
  	EXTCON_FAST_CHARGER,
  	EXTCON_SLOW_CHARGER,
  	EXTCON_CHARGE_DOWNSTREAM, /* Charging an external device */
  	EXTCON_HDMI,
  	EXTCON_MHL,
  	EXTCON_DVI,
  	EXTCON_VGA,
  	EXTCON_DOCK,
  	EXTCON_LINE_IN,
  	EXTCON_LINE_OUT,
  	EXTCON_MIC_IN,
  	EXTCON_HEADPHONE_OUT,
  	EXTCON_SPDIF_IN,
  	EXTCON_SPDIF_OUT,
  	EXTCON_VIDEO_IN,
  	EXTCON_VIDEO_OUT,
  	EXTCON_MECHANICAL,
  };
  extern const char *extcon_cable_name[];
  
  struct extcon_cable;
  
  /**
   * struct extcon_dev - An extcon device represents one external connector.
   * @name	The name of this extcon device. Parent device name is used
   *		if NULL.
   * @supported_cable	Array of supported cable name ending with NULL.
   *			If supported_cable is NULL, cable name related APIs
   *			are disabled.
   * @mutually_exclusive	Array of mutually exclusive set of cables that cannot
   *			be attached simultaneously. The array should be
   *			ending with NULL or be NULL (no mutually exclusive
   *			cables). For example, if it is { 0x7, 0x30, 0}, then,
   *			{0, 1}, {0, 1, 2}, {0, 2}, {1, 2}, or {4, 5} cannot
   *			be attached simulataneously. {0x7, 0} is equivalent to
   *			{0x3, 0x6, 0x5, 0}. If it is {0xFFFFFFFF, 0}, there
   *			can be no simultaneous connections.
   * @print_name	An optional callback to override the method to print the
   *		name of the extcon device.
   * @print_state	An optional callback to override the method to print the
   *		status of the extcon device.
   * @dev		Device of this extcon. Do not provide at register-time.
   * @state	Attach/detach state of this extcon. Do not provide at
   *		register-time
   * @nh	Notifier for the state change events from this extcon
   * @entry	To support list of extcon devices so that uses can search
   *		for extcon devices based on the extcon name.
   * @lock
   * @max_supported	Internal value to store the number of cables.
   * @extcon_dev_type	Device_type struct to provide attribute_groups
   *			customized for each extcon device.
   * @cables	Sysfs subdirectories. Each represents one cable.
   *
   * In most cases, users only need to provide "User initializing data" of
   * this struct when registering an extcon. In some exceptional cases,
   * optional callbacks may be needed. However, the values in "internal data"
   * are overwritten by register function.
   */
  struct extcon_dev {
  	/* --- Optional user initializing data --- */
  	const char	*name;
  	const char **supported_cable;
  	const u32	*mutually_exclusive;
  
  	/* --- Optional callbacks to override class functions --- */
  	ssize_t	(*print_name)(struct extcon_dev *edev, char *buf);
  	ssize_t	(*print_state)(struct extcon_dev *edev, char *buf);
  
  	/* --- Internal data. Please do not set. --- */
  	struct device	*dev;
  	u32		state;
  	struct raw_notifier_head nh;
  	struct list_head entry;
  	spinlock_t lock; /* could be called by irq handler */
  	int max_supported;
  
  	/* /sys/class/extcon/.../cable.n/... */
  	struct device_type extcon_dev_type;
  	struct extcon_cable *cables;
  	/* /sys/class/extcon/.../mutually_exclusive/... */
  	struct attribute_group attr_g_muex;
  	struct attribute **attrs_muex;
  	struct device_attribute *d_attrs_muex;
  };
  
  /**
   * 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 */
  };
  
  /**
   * struct extcon_specific_cable_nb - An internal data for
   *				extcon_register_interest().
   * @internal_nb	a notifier block bridging extcon notifier and cable notifier.
   * @user_nb	user provided notifier block for events from a specific cable.
   * @cable_index	the target cable.
   * @edev	the target extcon device.
   * @previous_value	the saved previous event value.
   */
  struct extcon_specific_cable_nb {
  	struct notifier_block internal_nb;
  	struct notifier_block *user_nb;
  	int cable_index;
  	struct extcon_dev *edev;
  	unsigned long previous_value;
  };
  
  #if IS_ENABLED(CONFIG_EXTCON)
  
  /*
   * Following APIs are for notifiers or configurations.
   * Notifiers are the external port and connection devices.
   */
  extern int extcon_dev_register(struct extcon_dev *edev, struct device *dev);
  extern void extcon_dev_unregister(struct extcon_dev *edev);
  extern struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name);
  
  /*
   * get/set/update_state access the 32b encoded state value, which represents
   * states of all possible cables of the multistate port. For example, if one
   * calls extcon_set_state(edev, 0x7), it may mean that all the three cables
   * are attached to the port.
   */
  static inline u32 extcon_get_state(struct extcon_dev *edev)
  {
  	return edev->state;
  }
  
  extern int extcon_set_state(struct extcon_dev *edev, u32 state);
  extern int extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state);
  
  /*
   * get/set_cable_state access each bit of the 32b encoded state value.
   * They are used to access the status of each cable based on the cable_name
   * or cable_index, which is retrived by extcon_find_cable_index
   */
  extern int extcon_find_cable_index(struct extcon_dev *sdev,
  				   const char *cable_name);
  extern int extcon_get_cable_state_(struct extcon_dev *edev, int cable_index);
  extern int extcon_set_cable_state_(struct extcon_dev *edev, int cable_index,
  				   bool cable_state);
  
  extern int extcon_get_cable_state(struct extcon_dev *edev,
  				  const char *cable_name);
  extern int extcon_set_cable_state(struct extcon_dev *edev,
  				  const char *cable_name, bool cable_state);
  
  /*
   * Following APIs are for notifiees (those who want to be notified)
   * to register a callback for events from a specific cable of the extcon.
   * Notifiees are the connected device drivers wanting to get notified by
   * a specific external port of a connection device.
   */
  extern int extcon_register_interest(struct extcon_specific_cable_nb *obj,
  				    const char *extcon_name,
  				    const char *cable_name,
  				    struct notifier_block *nb);
  extern int extcon_unregister_interest(struct extcon_specific_cable_nb *nb);
  
  /*
   * Following APIs are to monitor every action of a notifier.
   * Registerer gets notified for every external port of a connection device.
   * Probably this could be used to debug an action of notifier; however,
   * we do not recommend to use this at normal 'notifiee' device drivers who
   * want to be notified by a specific external port of the notifier.
   */
  extern int extcon_register_notifier(struct extcon_dev *edev,
  				    struct notifier_block *nb);
  extern int extcon_unregister_notifier(struct extcon_dev *edev,
  				      struct notifier_block *nb);
  #else /* CONFIG_EXTCON */
  static inline int extcon_dev_register(struct extcon_dev *edev,
  				      struct device *dev)
  {
  	return 0;
  }
  
  static inline void extcon_dev_unregister(struct extcon_dev *edev) { }
  
  static inline u32 extcon_get_state(struct extcon_dev *edev)
  {
  	return 0;
  }
  
  static inline int extcon_set_state(struct extcon_dev *edev, u32 state)
  {
  	return 0;
  }
  
  static inline int extcon_update_state(struct extcon_dev *edev, u32 mask,
  				       u32 state)
  {
  	return 0;
  }
  
  static inline int extcon_find_cable_index(struct extcon_dev *edev,
  					  const char *cable_name)
  {
  	return 0;
  }
  
  static inline int extcon_get_cable_state_(struct extcon_dev *edev,
  					  int cable_index)
  {
  	return 0;
  }
  
  static inline int extcon_set_cable_state_(struct extcon_dev *edev,
  					  int cable_index, bool cable_state)
  {
  	return 0;
  }
  
  static inline int extcon_get_cable_state(struct extcon_dev *edev,
  			const char *cable_name)
  {
  	return 0;
  }
  
  static inline int extcon_set_cable_state(struct extcon_dev *edev,
  			const char *cable_name, int state)
  {
  	return 0;
  }
  
  static inline struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
  {
  	return NULL;
  }
  
  static inline int extcon_register_notifier(struct extcon_dev *edev,
  					   struct notifier_block *nb)
  {
  	return 0;
  }
  
  static inline int extcon_unregister_notifier(struct extcon_dev *edev,
  					     struct notifier_block *nb)
  {
  	return 0;
  }
  
  static inline int extcon_register_interest(struct extcon_specific_cable_nb *obj,
  					   const char *extcon_name,
  					   const char *cable_name,
  					   struct notifier_block *nb)
  {
  	return 0;
  }
  
  static inline int extcon_unregister_interest(struct extcon_specific_cable_nb
  						    *obj)
  {
  	return 0;
  }
  #endif /* CONFIG_EXTCON */
  #endif /* __LINUX_EXTCON_H__ */
  