/*
 *  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__ */