extcon.h

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/*
 *  External connector (extcon) class driver
 *
 * Copyright (C) 2012 Samsung Electronics
 * Author: Donggeun Kim <[email protected]>
 * Author: MyungJoo Ham <[email protected]>
 *
 * based on switch class driver
 * Copyright (C) 2008 Google, Inc.
 * Author: Mike Lockwood <[email protected]>
 *
 * 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 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 {
    /* --- 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 {
    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 {
    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__ */