Merge tag 'v3.10.55' into update

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / extcon / extcon-class.c

/*
 *  drivers/extcon/extcon_class.c
 *
 *  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 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/slab.h>
#include <linux/sysfs.h>

/*
 * extcon_cable_name suggests the standard cable names for commonly used
 * cable types.
 *
 * However, please do not use extcon_cable_name directly for extcon_dev
 * struct's supported_cable pointer unless your device really supports
 * every single port-type of the following cable names. Please choose cable
 * names that are actually used in your extcon device.
 */
const char extcon_cable_name[][CABLE_NAME_MAX + 1] = {
        [EXTCON_USB]            = "USB",
        [EXTCON_USB_HOST]       = "USB-Host",
        [EXTCON_TA]             = "TA",
        [EXTCON_FAST_CHARGER]   = "Fast-charger",
        [EXTCON_SLOW_CHARGER]   = "Slow-charger",
        [EXTCON_CHARGE_DOWNSTREAM]      = "Charge-downstream",
        [EXTCON_HDMI]           = "HDMI",
        [EXTCON_MHL]            = "MHL",
        [EXTCON_DVI]            = "DVI",
        [EXTCON_VGA]            = "VGA",
        [EXTCON_DOCK]           = "Dock",
        [EXTCON_LINE_IN]        = "Line-in",
        [EXTCON_LINE_OUT]       = "Line-out",
        [EXTCON_MIC_IN]         = "Microphone",
        [EXTCON_HEADPHONE_OUT]  = "Headphone",
        [EXTCON_SPDIF_IN]       = "SPDIF-in",
        [EXTCON_SPDIF_OUT]      = "SPDIF-out",
        [EXTCON_VIDEO_IN]       = "Video-in",
        [EXTCON_VIDEO_OUT]      = "Video-out",
        [EXTCON_MECHANICAL]     = "Mechanical",
};

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 ssize_t state_show(struct device *dev, struct device_attribute *attr,
                          char *buf)
{
        int i, count = 0;
        struct extcon_dev *edev = (struct extcon_dev *) dev_get_drvdata(dev);

        if (edev->print_state) {
                int ret = edev->print_state(edev, buf);

                if (ret >= 0)
                        return ret;
                /* Use default if failed */
        }

        if (edev->max_supported == 0)
                return sprintf(buf, "%u\n", edev->state);

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

        return count;
}

int extcon_set_state(struct extcon_dev *edev, u32 state);
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 = (struct extcon_dev *) 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 ssize_t name_show(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct extcon_dev *edev = (struct extcon_dev *) dev_get_drvdata(dev);

        /* Optional callback given by the user */
        if (edev->print_name) {
                int ret = edev->print_name(edev, buf);
                if (ret >= 0)
                        return ret;
        }

        return sprintf(buf, "%s\n", dev_name(edev->dev));
}

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);

        return sprintf(buf, "%s\n",
                       cable->edev->supported_cable[cable->cable_index]);
}

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);

        return sprintf(buf, "%d\n",
                       extcon_get_cable_state_(cable->edev,
                                               cable->cable_index));
}

static ssize_t cable_state_store(struct device *dev,
                                 struct device_attribute *attr, const char *buf,
                                 size_t count)
{
        struct extcon_cable *cable = container_of(attr, struct extcon_cable,
                                                  attr_state);
        int ret, state;

        ret = sscanf(buf, "%d", &state);
        if (ret == 0)
                ret = -EINVAL;
        else
                ret = extcon_set_cable_state_(cable->edev, cable->cable_index,
                                              state);

        if (ret < 0)
                return ret;
        return count;
}

/**
 * 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;
        unsigned long flags;

        spin_lock_irqsave(&edev->lock, flags);

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

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

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

                raw_notifier_call_chain(&edev->nh, old_state, 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)
{
        return extcon_update_state(edev, 0xffffffff, state);
}
EXPORT_SYMBOL_GPL(extcon_set_state);

/**
 * extcon_find_cable_index() - Get the cable index based on the cable name.
 * @edev:       the extcon device that has the cable.
 * @cable_name: cable name to be searched.
 *
 * Note that accessing a cable state based on cable_index is faster than
 * cable_name because using cable_name induces a loop with strncmp().
 * Thus, when get/set_cable_state is repeatedly used, using cable_index
 * is recommended.
 */
int extcon_find_cable_index(struct extcon_dev *edev, const char *cable_name)
{
        int i;

        if (edev->supported_cable) {
                for (i = 0; edev->supported_cable[i]; i++) {
                        if (!strncmp(edev->supported_cable[i],
                                cable_name, CABLE_NAME_MAX))
                                return i;
                }
        }

        return -EINVAL;
}
EXPORT_SYMBOL_GPL(extcon_find_cable_index);

/**
 * extcon_get_cable_state_() - Get the status of a specific cable.
 * @edev:       the extcon device that has the cable.
 * @index:      cable index that can be retrieved by extcon_find_cable_index().
 */
int extcon_get_cable_state_(struct extcon_dev *edev, int index)
{
        if (index < 0 || (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)
{
        return extcon_get_cable_state_(edev, extcon_find_cable_index
                                                (edev, cable_name));
}
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.
 * @index:      cable index that can be retrieved by extcon_find_cable_index().
 * @cable_state:        the new cable status. The default semantics is
 *                      true: attached / false: detached.
 */
int extcon_set_cable_state_(struct extcon_dev *edev,
                        int index, bool cable_state)
{
        u32 state;

        if (index < 0 || (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)
{
        return extcon_set_cable_state_(edev, extcon_find_cable_index
                                        (edev, cable_name), 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;

        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);

static int _call_per_cable(struct notifier_block *nb, unsigned long val,
                           void *ptr)
{
        struct extcon_specific_cable_nb *obj = container_of(nb,
                        struct extcon_specific_cable_nb, internal_nb);
        struct extcon_dev *edev = ptr;

        if ((val & (1 << obj->cable_index)) !=
            (edev->state & (1 << obj->cable_index))) {
                bool cable_state = true;

                obj->previous_value = val;

                if (val & (1 << obj->cable_index))
                        cable_state = false;

                return obj->user_nb->notifier_call(obj->user_nb,
                                cable_state, ptr);
        }

        return NOTIFY_OK;
}

/**
 * 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)
{
        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 = extcon_find_cable_index(obj->edev, cable_name);
                if (obj->cable_index < 0)
                        return obj->cable_index;

                obj->user_nb = nb;

                obj->internal_nb.notifier_call = _call_per_cable;

                return raw_notifier_chain_register(&obj->edev->nh, &obj->internal_nb);
        } 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 = (struct extcon_dev *)dev_get_drvdata(dev);

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

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

                return -ENODEV;
        }
}

/**
 * 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)
{
        if (!obj)
                return -EINVAL;

        return raw_notifier_chain_unregister(&obj->edev->nh, &obj->internal_nb);
}

/**
 * extcon_register_notifier() - Register a notifiee to get notified by
 *                            any attach status changes from the extcon.
 * @edev:       the extcon device.
 * @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,
                        struct notifier_block *nb)
{
        return raw_notifier_chain_register(&edev->nh, nb);
}
EXPORT_SYMBOL_GPL(extcon_register_notifier);

/**
 * extcon_unregister_notifier() - Unregister a notifiee from the extcon device.
 * @edev:       the extcon device.
 * @nb:         a registered notifier block to be unregistered.
 */
int extcon_unregister_notifier(struct extcon_dev *edev,
                        struct notifier_block *nb)
{
        return raw_notifier_chain_unregister(&edev->nh, nb);
}
EXPORT_SYMBOL_GPL(extcon_unregister_notifier);

static struct device_attribute extcon_attrs[] = {
        __ATTR(state, S_IRUGO | S_IWUSR, state_show, state_store),
        __ATTR_RO(name),
        __ATTR_NULL,
};

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_attrs = extcon_attrs;

#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)
{
        kfree(dev);
}

static const char *muex_name = "mutually_exclusive";
static void dummy_sysfs_dev_release(struct device *dev)
{
}

/**
 * extcon_dev_register() - Register a new extcon device
 * @edev        : the new extcon device (should be allocated before calling)
 * @dev         : the parent device for this extcon device.
 *
 * 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, struct device *dev)
{
        int ret, index = 0;

        if (!extcon_class) {
                ret = create_extcon_class();
                if (ret < 0)
                        return ret;
        }

        if (edev->supported_cable) {
                /* Get size of array */
                for (index = 0; edev->supported_cable[index]; index++)
                        ;
                edev->max_supported = index;
        } else {
                edev->max_supported = 0;
        }

        if (index > SUPPORTED_CABLE_MAX) {
                dev_err(edev->dev, "extcon: maximum number of supported cables exceeded.\n");
                return -EINVAL;
        }

        edev->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
        if (!edev->dev)
                return -ENOMEM;
        edev->dev->parent = dev;
        edev->dev->class = extcon_class;
        edev->dev->release = extcon_dev_release;

        dev_set_name(edev->dev, edev->name ? edev->name : dev_name(dev));

        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 = 0644;
                        cable->attr_state.show = cable_state_show;
                        cable->attr_state.store = cable_state_store;
                }
        }

        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);

        RAW_INIT_NOTIFIER_HEAD(&edev->nh);

        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:
        kfree(edev->dev);
        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;

        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;
        }

        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
        device_unregister(edev->dev);
        put_device(edev->dev);
}
EXPORT_SYMBOL_GPL(extcon_dev_unregister);

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("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");