extcon.h

/*
 *  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/device.h>
#include <linux/notifier.h>
#include <linux/sysfs.h>

#define SUPPORTED_CABLE_MAX	32
#define CABLE_NAME_MAX		30

/*
 * The standard cable name is to help support general notifier
 * and notifiee 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/notifiee 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 notifiee and notifier should be able to handle such
 * string and if the notifiee can negotiate the protocol or identify,
 * 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[][CABLE_NAME_MAX + 1];

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 names 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 users 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 retrieved 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.
 * Registrar 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 for 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__ */