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[linux-2.6/btrfs-unstable.git] / drivers / extcon / extcon.c

/*
 *  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

static const char *extcon_name[] =  {
        [EXTCON_NONE]           = "NONE",

        /* USB external connector */
        [EXTCON_USB]            = "USB",
        [EXTCON_USB_HOST]       = "USB-HOST",

        /* Charger external connector */
        [EXTCON_TA]             = "TA",
        [EXTCON_FAST_CHARGER]   = "FAST-CHARGER",
        [EXTCON_SLOW_CHARGER]   = "SLOW-CHARGER",
        [EXTCON_CHARGE_DOWNSTREAM] = "CHARGE-DOWNSTREAM",

        /* Audio/Video external connector */
        [EXTCON_LINE_IN]        = "LINE-IN",
        [EXTCON_LINE_OUT]       = "LINE-OUT",
        [EXTCON_MICROPHONE]     = "MICROPHONE",
        [EXTCON_HEADPHONE]      = "HEADPHONE",

        [EXTCON_HDMI]           = "HDMI",
        [EXTCON_MHL]            = "MHL",
        [EXTCON_DVI]            = "DVI",
        [EXTCON_VGA]            = "VGA",
        [EXTCON_SPDIF_IN]       = "SPDIF-IN",
        [EXTCON_SPDIF_OUT]      = "SPDIF-OUT",
        [EXTCON_VIDEO_IN]       = "VIDEO-IN",
        [EXTCON_VIDEO_OUT]      = "VIDEO-OUT",

        /* Etc external connector */
        [EXTCON_DOCK]           = "DOCK",
        [EXTCON_JIG]            = "JIG",
        [EXTCON_MECHANICAL]     = "MECHANICAL",

        NULL,
};

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 find_cable_id_by_name(struct extcon_dev *edev, const char *name)
{
        int id = -EINVAL;
        int i = 0;

        /* Find the id of extcon cable */
        while (extcon_name[i]) {
                if (!strncmp(extcon_name[i], name, CABLE_NAME_MAX)) {
                        id = i;
                        break;
                }
                i++;
        }

        return id;
}

static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
{
        int id;

        if (edev->max_supported == 0)
                return -EINVAL;

        /* Find the the number of extcon cable */
        id = find_cable_id_by_name(edev, name);
        if (id < 0)
                return id;

        return find_cable_index_by_id(edev, id);
}

static bool is_extcon_changed(u32 prev, u32 new, int idx, bool *attached)
{
        if (((prev >> idx) & 0x1) != ((new >> idx) & 0x1)) {
                *attached = new ? true : false;
                return true;
        }

        return false;
}

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\n", edev->state);

        for (i = 0; i < edev->max_supported; i++) {
                count += sprintf(buf + count, "%s=%d\n",
                                extcon_name[edev->supported_cable[i]],
                                 !!(edev->state & (1 << i)));
        }

        return count;
}

static ssize_t state_store(struct device *dev, struct device_attribute *attr,
                           const char *buf, size_t count)
{
        u32 state;
        ssize_t ret = 0;
        struct extcon_dev *edev = dev_get_drvdata(dev);

        ret = sscanf(buf, "0x%x", &state);
        if (ret == 0)
                ret = -EINVAL;
        else
                ret = extcon_set_state(edev, state);

        if (ret < 0)
                return ret;

        return count;
}
static DEVICE_ATTR_RW(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\n", 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\n",
                        extcon_name[cable->edev->supported_cable[i]]);
}

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\n",
                       extcon_get_cable_state_(cable->edev,
                                               cable->edev->supported_cable[i]));
}

/**
 * extcon_update_state() - Update the cable attach states of the extcon device
 *                         only for the masked bits.
 * @edev:       the extcon device
 * @mask:       the bit mask to designate updated bits.
 * @state:      new cable attach status for @edev
 *
 * Changing the state sends uevent with environment variable containing
 * the name of extcon device (envp[0]) and the state output (envp[1]).
 * Tizen uses this format for extcon device to get events from ports.
 * Android uses this format as well.
 *
 * Note that the notifier provides which bits are changed in the state
 * variable with the val parameter (second) to the callback.
 */
int extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state)
{
        char name_buf[120];
        char state_buf[120];
        char *prop_buf;
        char *envp[3];
        int env_offset = 0;
        int length;
        int index;
        unsigned long flags;
        bool attached;

        if (!edev)
                return -EINVAL;

        spin_lock_irqsave(&edev->lock, flags);

        if (edev->state != ((edev->state & ~mask) | (state & mask))) {
                u32 old_state;

                if (check_mutually_exclusive(edev, (edev->state & ~mask) |
                                                   (state & mask))) {
                        spin_unlock_irqrestore(&edev->lock, flags);
                        return -EPERM;
                }

                old_state = edev->state;
                edev->state &= ~mask;
                edev->state |= state & mask;

                for (index = 0; index < edev->max_supported; index++) {
                        if (is_extcon_changed(old_state, edev->state, index,
                                              &attached))
                                raw_notifier_call_chain(&edev->nh[index],
                                                        attached, edev);
                }

                /* This could be in interrupt handler */
                prop_buf = (char *)get_zeroed_page(GFP_ATOMIC);
                if (prop_buf) {
                        length = name_show(&edev->dev, NULL, prop_buf);
                        if (length > 0) {
                                if (prop_buf[length - 1] == '\n')
                                        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] == '\n')
                                        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);
                } else {
                        /* Unlock early before uevent */
                        spin_unlock_irqrestore(&edev->lock, flags);

                        dev_err(&edev->dev, "out of memory in extcon_set_state\n");
                        kobject_uevent(&edev->dev.kobj, KOBJ_CHANGE);
                }
        } else {
                /* No changes */
                spin_unlock_irqrestore(&edev->lock, flags);
        }

        return 0;
}
EXPORT_SYMBOL_GPL(extcon_update_state);

/**
 * extcon_set_state() - Set the cable attach states of the extcon device.
 * @edev:       the extcon device
 * @state:      new cable attach status for @edev
 *
 * Note that notifier provides which bits are changed in the state
 * variable with the val parameter (second) to the callback.
 */
int extcon_set_state(struct extcon_dev *edev, u32 state)
{
        if (!edev)
                return -EINVAL;

        return extcon_update_state(edev, 0xffffffff, state);
}
EXPORT_SYMBOL_GPL(extcon_set_state);

/**
 * extcon_get_cable_state_() - Get the status of a specific cable.
 * @edev:       the extcon device that has the cable.
 * @id:         the unique id of each external connector in extcon enumeration.
 */
int extcon_get_cable_state_(struct extcon_dev *edev, const unsigned int id)
{
        int index;

        if (!edev)
                return -EINVAL;

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

        if (edev->max_supported && edev->max_supported <= index)
                return -EINVAL;

        return !!(edev->state & (1 << index));
}
EXPORT_SYMBOL_GPL(extcon_get_cable_state_);

/**
 * extcon_get_cable_state() - Get the status of a specific cable.
 * @edev:       the extcon device that has the cable.
 * @cable_name: cable name.
 *
 * Note that this is slower than extcon_get_cable_state_.
 */
int extcon_get_cable_state(struct extcon_dev *edev, const char *cable_name)
{
        int id;

        id = find_cable_id_by_name(edev, cable_name);
        if (id < 0)
                return id;

        return extcon_get_cable_state_(edev, id);
}
EXPORT_SYMBOL_GPL(extcon_get_cable_state);

/**
 * extcon_set_cable_state_() - Set the status of a specific cable.
 * @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.
 */
int extcon_set_cable_state_(struct extcon_dev *edev, unsigned int id,
                                bool cable_state)
{
        u32 state;
        int index;

        if (!edev)
                return -EINVAL;

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

        if (edev->max_supported && edev->max_supported <= index)
                return -EINVAL;

        state = cable_state ? (1 << index) : 0;
        return extcon_update_state(edev, 1 << index, state);
}
EXPORT_SYMBOL_GPL(extcon_set_cable_state_);

/**
 * extcon_set_cable_state() - Set the status of a specific cable.
 * @edev:               the extcon device that has the cable.
 * @cable_name:         cable name.
 * @cable_state:        the new cable status. The default semantics is
 *                      true: attached / false: detached.
 *
 * Note that this is slower than extcon_set_cable_state_.
 */
int extcon_set_cable_state(struct extcon_dev *edev,
                        const char *cable_name, bool cable_state)
{
        int id;

        id = find_cable_id_by_name(edev, cable_name);
        if (id < 0)
                return id;

        return extcon_set_cable_state_(edev, id, cable_state);
}
EXPORT_SYMBOL_GPL(extcon_set_cable_state);

/**
 * 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_interest() - Register a notifier for a state change of a
 *                              specific cable, not an entier set of cables of a
 *                              extcon device.
 * @obj:                an empty extcon_specific_cable_nb object to be returned.
 * @extcon_name:        the name of extcon device.
 *                      if NULL, extcon_register_interest will register
 *                      every cable with the target cable_name given.
 * @cable_name:         the target cable name.
 * @nb:                 the notifier block to get notified.
 *
 * Provide an empty extcon_specific_cable_nb. extcon_register_interest() sets
 * the struct for you.
 *
 * extcon_register_interest is a helper function for those who want to get
 * notification for a single specific cable's status change. If a user wants
 * to get notification for any changes of all cables of a extcon device,
 * he/she should use the general extcon_register_notifier().
 *
 * 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_interest(struct extcon_specific_cable_nb *obj,
                             const char *extcon_name, const char *cable_name,
                             struct notifier_block *nb)
{
        unsigned long flags;
        int ret;

        if (!obj || !cable_name || !nb)
                return -EINVAL;

        if (extcon_name) {
                obj->edev = extcon_get_extcon_dev(extcon_name);
                if (!obj->edev)
                        return -ENODEV;

                obj->cable_index = find_cable_index_by_name(obj->edev,
                                                        cable_name);
                if (obj->cable_index < 0)
                        return obj->cable_index;

                obj->user_nb = nb;

                spin_lock_irqsave(&obj->edev->lock, flags);
                ret = raw_notifier_chain_register(
                                        &obj->edev->nh[obj->cable_index],
                                        obj->user_nb);
                spin_unlock_irqrestore(&obj->edev->lock, flags);
        } else {
                struct class_dev_iter iter;
                struct extcon_dev *extd;
                struct device *dev;

                if (!extcon_class)
                        return -ENODEV;
                class_dev_iter_init(&iter, extcon_class, NULL, NULL);
                while ((dev = class_dev_iter_next(&iter))) {
                        extd = dev_get_drvdata(dev);

                        if (find_cable_index_by_name(extd, cable_name) < 0)
                                continue;

                        class_dev_iter_exit(&iter);
                        return extcon_register_interest(obj, extd->name,
                                                cable_name, nb);
                }

                ret = -ENODEV;
        }

        return ret;
}
EXPORT_SYMBOL_GPL(extcon_register_interest);

/**
 * extcon_unregister_interest() - Unregister the notifier registered by
 *                                extcon_register_interest().
 * @obj:        the extcon_specific_cable_nb object returned by
 *              extcon_register_interest().
 */
int extcon_unregister_interest(struct extcon_specific_cable_nb *obj)
{
        unsigned long flags;
        int ret;

        if (!obj)
                return -EINVAL;

        spin_lock_irqsave(&obj->edev->lock, flags);
        ret = raw_notifier_chain_unregister(
                        &obj->edev->nh[obj->cable_index], obj->user_nb);
        spin_unlock_irqrestore(&obj->edev->lock, flags);

        return ret;
}
EXPORT_SYMBOL_GPL(extcon_unregister_interest);

/**
 * 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;

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

        idx = find_cable_index_by_id(edev, id);

        spin_lock_irqsave(&edev->lock, flags);
        ret = raw_notifier_chain_register(&edev->nh[idx], nb);
        spin_unlock_irqrestore(&edev->lock, flags);

        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);

        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);

static int devm_extcon_dev_match(struct device *dev, void *res, void *data)
{
        struct extcon_dev **r = res;

        if (WARN_ON(!r || !*r))
                return 0;

        return *r == data;
}

static void devm_extcon_dev_release(struct device *dev, void *res)
{
        extcon_dev_free(*(struct extcon_dev **)res);
}

/**
 * devm_extcon_dev_allocate - Allocate managed extcon device
 * @dev:                device owning the extcon device being created
 * @supported_cable:    Array of supported extcon ending with EXTCON_NONE.
 *                      If supported_cable is NULL, cable name related APIs
 *                      are disabled.
 *
 * This function manages automatically the memory of extcon device using device
 * resource management and simplify the control of freeing the memory of extcon
 * device.
 *
 * Returns the pointer memory of allocated extcon_dev if success
 * or ERR_PTR(err) if fail
 */
struct extcon_dev *devm_extcon_dev_allocate(struct device *dev,
                                        const unsigned int *supported_cable)
{
        struct extcon_dev **ptr, *edev;

        ptr = devres_alloc(devm_extcon_dev_release, sizeof(*ptr), GFP_KERNEL);
        if (!ptr)
                return ERR_PTR(-ENOMEM);

        edev = extcon_dev_allocate(supported_cable);
        if (IS_ERR(edev)) {
                devres_free(ptr);
                return edev;
        }

        edev->dev.parent = dev;

        *ptr = edev;
        devres_add(dev, ptr);

        return edev;
}
EXPORT_SYMBOL_GPL(devm_extcon_dev_allocate);

void devm_extcon_dev_free(struct device *dev, struct extcon_dev *edev)
{
        WARN_ON(devres_release(dev, devm_extcon_dev_release,
                               devm_extcon_dev_match, edev));
}
EXPORT_SYMBOL_GPL(devm_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\n");
                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\n");
                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)\n",
                                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);

static void devm_extcon_dev_unreg(struct device *dev, void *res)
{
        extcon_dev_unregister(*(struct extcon_dev **)res);
}

/**
 * devm_extcon_dev_register() - Resource-managed extcon_dev_register()
 * @dev:        device to allocate extcon device
 * @edev:       the new extcon device to register
 *
 * Managed extcon_dev_register() function. If extcon device is attached with
 * this function, that extcon device is automatically unregistered on driver
 * detach. Internally this function calls extcon_dev_register() function.
 * To get more information, refer that function.
 *
 * If extcon device is registered with this function and the device needs to be
 * unregistered separately, devm_extcon_dev_unregister() should be used.
 *
 * Returns 0 if success or negaive error number if failure.
 */
int devm_extcon_dev_register(struct device *dev, struct extcon_dev *edev)
{
        struct extcon_dev **ptr;
        int ret;

        ptr = devres_alloc(devm_extcon_dev_unreg, sizeof(*ptr), GFP_KERNEL);
        if (!ptr)
                return -ENOMEM;

        ret = extcon_dev_register(edev);
        if (ret) {
                devres_free(ptr);
                return ret;
        }

        *ptr = edev;
        devres_add(dev, ptr);

        return 0;
}
EXPORT_SYMBOL_GPL(devm_extcon_dev_register);

/**
 * devm_extcon_dev_unregister() - Resource-managed extcon_dev_unregister()
 * @dev:        device the extcon belongs to
 * @edev:       the extcon device to unregister
 *
 * Unregister extcon device that is registered with devm_extcon_dev_register()
 * function.
 */
void devm_extcon_dev_unregister(struct device *dev, struct extcon_dev *edev)
{
        WARN_ON(devres_release(dev, devm_extcon_dev_unreg,
                               devm_extcon_dev_match, edev));
}
EXPORT_SYMBOL_GPL(devm_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_err(dev, "device does not have a device node entry\n");
                return ERR_PTR(-EINVAL);
        }

        node = of_parse_phandle(dev->of_node, "extcon", index);
        if (!node) {
                dev_err(dev, "failed to get phandle in %s node\n",
                        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);
                        return edev;
                }
        }
        mutex_unlock(&extcon_dev_list_lock);

        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");