doc: Update rcu_assign_pointer() definition in whatisRCU.txt

[linux/fpc-iii.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/of.h>
#include <linux/slab.h>
#include <linux/sysfs.h>

#include "extcon.h"

#define SUPPORTED_CABLE_MAX     32
#define CABLE_NAME_MAX          30

struct __extcon_info {
        unsigned int type;
        unsigned int id;
        const char *name;

} extcon_info[] = {
        [EXTCON_NONE] = {
                .type = EXTCON_TYPE_MISC,
                .id = EXTCON_NONE,
                .name = "NONE",
        },

        /* USB external connector */
        [EXTCON_USB] = {
                .type = EXTCON_TYPE_USB,
                .id = EXTCON_USB,
                .name = "USB",
        },
        [EXTCON_USB_HOST] = {
                .type = EXTCON_TYPE_USB,
                .id = EXTCON_USB_HOST,
                .name = "USB-HOST",
        },

        /* Charging external connector */
        [EXTCON_CHG_USB_SDP] = {
                .type = EXTCON_TYPE_CHG | EXTCON_TYPE_USB,
                .id = EXTCON_CHG_USB_SDP,
                .name = "SDP",
        },
        [EXTCON_CHG_USB_DCP] = {
                .type = EXTCON_TYPE_CHG | EXTCON_TYPE_USB,
                .id = EXTCON_CHG_USB_DCP,
                .name = "DCP",
        },
        [EXTCON_CHG_USB_CDP] = {
                .type = EXTCON_TYPE_CHG | EXTCON_TYPE_USB,
                .id = EXTCON_CHG_USB_CDP,
                .name = "CDP",
        },
        [EXTCON_CHG_USB_ACA] = {
                .type = EXTCON_TYPE_CHG | EXTCON_TYPE_USB,
                .id = EXTCON_CHG_USB_ACA,
                .name = "ACA",
        },
        [EXTCON_CHG_USB_FAST] = {
                .type = EXTCON_TYPE_CHG | EXTCON_TYPE_USB,
                .id = EXTCON_CHG_USB_FAST,
                .name = "FAST-CHARGER",
        },
        [EXTCON_CHG_USB_SLOW] = {
                .type = EXTCON_TYPE_CHG | EXTCON_TYPE_USB,
                .id = EXTCON_CHG_USB_SLOW,
                .name = "SLOW-CHARGER",
        },
        [EXTCON_CHG_WPT] = {
                .type = EXTCON_TYPE_CHG,
                .id = EXTCON_CHG_WPT,
                .name = "WPT",
        },
        [EXTCON_CHG_USB_PD] = {
                .type = EXTCON_TYPE_CHG | EXTCON_TYPE_USB,
                .id = EXTCON_CHG_USB_PD,
                .name = "PD",
        },

        /* Jack external connector */
        [EXTCON_JACK_MICROPHONE] = {
                .type = EXTCON_TYPE_JACK,
                .id = EXTCON_JACK_MICROPHONE,
                .name = "MICROPHONE",
        },
        [EXTCON_JACK_HEADPHONE] = {
                .type = EXTCON_TYPE_JACK,
                .id = EXTCON_JACK_HEADPHONE,
                .name = "HEADPHONE",
        },
        [EXTCON_JACK_LINE_IN] = {
                .type = EXTCON_TYPE_JACK,
                .id = EXTCON_JACK_LINE_IN,
                .name = "LINE-IN",
        },
        [EXTCON_JACK_LINE_OUT] = {
                .type = EXTCON_TYPE_JACK,
                .id = EXTCON_JACK_LINE_OUT,
                .name = "LINE-OUT",
        },
        [EXTCON_JACK_VIDEO_IN] = {
                .type = EXTCON_TYPE_JACK,
                .id = EXTCON_JACK_VIDEO_IN,
                .name = "VIDEO-IN",
        },
        [EXTCON_JACK_VIDEO_OUT] = {
                .type = EXTCON_TYPE_JACK,
                .id = EXTCON_JACK_VIDEO_OUT,
                .name = "VIDEO-OUT",
        },
        [EXTCON_JACK_SPDIF_IN] = {
                .type = EXTCON_TYPE_JACK,
                .id = EXTCON_JACK_SPDIF_IN,
                .name = "SPDIF-IN",
        },
        [EXTCON_JACK_SPDIF_OUT] = {
                .type = EXTCON_TYPE_JACK,
                .id = EXTCON_JACK_SPDIF_OUT,
                .name = "SPDIF-OUT",
        },

        /* Display external connector */
        [EXTCON_DISP_HDMI] = {
                .type = EXTCON_TYPE_DISP,
                .id = EXTCON_DISP_HDMI,
                .name = "HDMI",
        },
        [EXTCON_DISP_MHL] = {
                .type = EXTCON_TYPE_DISP,
                .id = EXTCON_DISP_MHL,
                .name = "MHL",
        },
        [EXTCON_DISP_DVI] = {
                .type = EXTCON_TYPE_DISP,
                .id = EXTCON_DISP_DVI,
                .name = "DVI",
        },
        [EXTCON_DISP_VGA] = {
                .type = EXTCON_TYPE_DISP,
                .id = EXTCON_DISP_VGA,
                .name = "VGA",
        },
        [EXTCON_DISP_DP] = {
                .type = EXTCON_TYPE_DISP | EXTCON_TYPE_USB,
                .id = EXTCON_DISP_DP,
                .name = "DP",
        },
        [EXTCON_DISP_HMD] = {
                .type = EXTCON_TYPE_DISP | EXTCON_TYPE_USB,
                .id = EXTCON_DISP_HMD,
                .name = "HMD",
        },

        /* Miscellaneous external connector */
        [EXTCON_DOCK] = {
                .type = EXTCON_TYPE_MISC,
                .id = EXTCON_DOCK,
                .name = "DOCK",
        },
        [EXTCON_JIG] = {
                .type = EXTCON_TYPE_MISC,
                .id = EXTCON_JIG,
                .name = "JIG",
        },
        [EXTCON_MECHANICAL] = {
                .type = EXTCON_TYPE_MISC,
                .id = EXTCON_MECHANICAL,
                .name = "MECHANICAL",
        },

        { /* sentinel */ }
};

/**
 * 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 */

        union extcon_property_value usb_propval[EXTCON_PROP_USB_CNT];
        union extcon_property_value chg_propval[EXTCON_PROP_CHG_CNT];
        union extcon_property_value jack_propval[EXTCON_PROP_JACK_CNT];
        union extcon_property_value disp_propval[EXTCON_PROP_DISP_CNT];

        unsigned long usb_bits[BITS_TO_LONGS(EXTCON_PROP_USB_CNT)];
        unsigned long chg_bits[BITS_TO_LONGS(EXTCON_PROP_CHG_CNT)];
        unsigned long jack_bits[BITS_TO_LONGS(EXTCON_PROP_JACK_CNT)];
        unsigned long disp_bits[BITS_TO_LONGS(EXTCON_PROP_DISP_CNT)];
};

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 get_extcon_type(unsigned int prop)
{
        switch (prop) {
        case EXTCON_PROP_USB_MIN ... EXTCON_PROP_USB_MAX:
                return EXTCON_TYPE_USB;
        case EXTCON_PROP_CHG_MIN ... EXTCON_PROP_CHG_MAX:
                return EXTCON_TYPE_CHG;
        case EXTCON_PROP_JACK_MIN ... EXTCON_PROP_JACK_MAX:
                return EXTCON_TYPE_JACK;
        case EXTCON_PROP_DISP_MIN ... EXTCON_PROP_DISP_MAX:
                return EXTCON_TYPE_DISP;
        default:
                return -EINVAL;
        }
}

static bool is_extcon_attached(struct extcon_dev *edev, unsigned int index)
{
        return !!(edev->state & BIT(index));
}

static bool is_extcon_changed(struct extcon_dev *edev, int index,
                                bool new_state)
{
        int state = !!(edev->state & BIT(index));
        return (state != new_state);
}

static bool is_extcon_property_supported(unsigned int id, unsigned int prop)
{
        int type;

        /* Check whether the property is supported or not. */
        type = get_extcon_type(prop);
        if (type < 0)
                return false;

        /* Check whether a specific extcon id supports the property or not. */
        return !!(extcon_info[id].type & type);
}

static int is_extcon_property_capability(struct extcon_dev *edev,
                                unsigned int id, int index,unsigned int prop)
{
        struct extcon_cable *cable;
        int type, ret;

        /* Check whether the property is supported or not. */
        type = get_extcon_type(prop);
        if (type < 0)
                return type;

        cable = &edev->cables[index];

        switch (type) {
        case EXTCON_TYPE_USB:
                ret = test_bit(prop - EXTCON_PROP_USB_MIN, cable->usb_bits);
                break;
        case EXTCON_TYPE_CHG:
                ret = test_bit(prop - EXTCON_PROP_CHG_MIN, cable->chg_bits);
                break;
        case EXTCON_TYPE_JACK:
                ret = test_bit(prop - EXTCON_PROP_JACK_MIN, cable->jack_bits);
                break;
        case EXTCON_TYPE_DISP:
                ret = test_bit(prop - EXTCON_PROP_DISP_MIN, cable->disp_bits);
                break;
        default:
                ret = -EINVAL;
        }

        return ret;
}

static void init_property(struct extcon_dev *edev, unsigned int id, int index)
{
        unsigned int type = extcon_info[id].type;
        struct extcon_cable *cable = &edev->cables[index];

        if (EXTCON_TYPE_USB & type)
                memset(cable->usb_propval, 0, sizeof(cable->usb_propval));
        if (EXTCON_TYPE_CHG & type)
                memset(cable->chg_propval, 0, sizeof(cable->chg_propval));
        if (EXTCON_TYPE_JACK & type)
                memset(cable->jack_propval, 0, sizeof(cable->jack_propval));
        if (EXTCON_TYPE_DISP & type)
                memset(cable->disp_propval, 0, sizeof(cable->disp_propval));
}

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_info[edev->supported_cable[i]].name,
                                 !!(edev->state & (1 << i)));
        }

        return count;
}
static DEVICE_ATTR_RO(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_info[cable->edev->supported_cable[i]].name);
}

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_state(cable->edev, cable->edev->supported_cable[i]));
}

/**
 * extcon_sync()        - Synchronize the states for both the attached/detached
 * @edev:               the extcon device that has the cable.
 *
 * This function send a notification to synchronize the all states of a
 * specific external connector
 */
int extcon_sync(struct extcon_dev *edev, unsigned int id)
{
        char name_buf[120];
        char state_buf[120];
        char *prop_buf;
        char *envp[3];
        int env_offset = 0;
        int length;
        int index;
        int state;
        unsigned long flags;

        if (!edev)
                return -EINVAL;

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

        spin_lock_irqsave(&edev->lock, flags);

        state = !!(edev->state & BIT(index));
        raw_notifier_call_chain(&edev->nh[index], state, edev);

        /* This could be in interrupt handler */
        prop_buf = (char *)get_zeroed_page(GFP_ATOMIC);
        if (!prop_buf) {
                /* 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);

                return -ENOMEM;
        }

        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);

        return 0;
}
EXPORT_SYMBOL_GPL(extcon_sync);

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

        if (!edev)
                return -EINVAL;

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

        spin_lock_irqsave(&edev->lock, flags);
        state = is_extcon_attached(edev, index);
        spin_unlock_irqrestore(&edev->lock, flags);

        return state;
}
EXPORT_SYMBOL_GPL(extcon_get_state);

/**
 * extcon_set_state() - Set the state of a external connector.
 *                      without a notification.
 * @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.
 *
 * This function only set the state of a external connector without
 * a notification. To synchronize the data of a external connector,
 * use extcon_set_state_sync() and extcon_sync().
 */
int extcon_set_state(struct extcon_dev *edev, unsigned int id,
                                bool cable_state)
{
        unsigned long flags;
        int index, ret = 0;

        if (!edev)
                return -EINVAL;

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

        spin_lock_irqsave(&edev->lock, flags);

        /* Check whether the external connector's state is changed. */
        if (!is_extcon_changed(edev, index, cable_state))
                goto out;

        if (check_mutually_exclusive(edev,
                (edev->state & ~BIT(index)) | (cable_state & BIT(index)))) {
                ret = -EPERM;
                goto out;
        }

        /*
         * Initialize the value of extcon property before setting
         * the detached state for an external connector.
         */
        if (!cable_state)
                init_property(edev, id, index);

        /* Update the state for a external connector. */
        if (cable_state)
                edev->state |= BIT(index);
        else
                edev->state &= ~(BIT(index));
out:
        spin_unlock_irqrestore(&edev->lock, flags);

        return ret;
}
EXPORT_SYMBOL_GPL(extcon_set_state);

/**
 * extcon_set_state_sync() - Set the state of a external connector
 *                      with a notification.
 * @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.
 *
 * This function set the state of external connector and synchronize the data
 * by usning a notification.
 */
int extcon_set_state_sync(struct extcon_dev *edev, unsigned int id,
                                bool cable_state)
{
        int ret, index;
        unsigned long flags;

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

        /* Check whether the external connector's state is changed. */
        spin_lock_irqsave(&edev->lock, flags);
        ret = is_extcon_changed(edev, index, cable_state);
        spin_unlock_irqrestore(&edev->lock, flags);
        if (!ret)
                return 0;

        ret = extcon_set_state(edev, id, cable_state);
        if (ret < 0)
                return ret;

        return extcon_sync(edev, id);
}
EXPORT_SYMBOL_GPL(extcon_set_state_sync);

/**
 * extcon_get_property() - Get the property value of a specific cable.
 * @edev:               the extcon device that has the cable.
 * @id:                 the unique id of each external connector
 *                      in extcon enumeration.
 * @prop:               the property id among enum extcon_property.
 * @prop_val:           the pointer which store the value of property.
 *
 * When getting the property value of external connector, the external connector
 * should be attached. If detached state, function just return 0 without
 * property value. Also, the each property should be included in the list of
 * supported properties according to the type of external connectors.
 *
 * Returns 0 if success or error number if fail
 */
int extcon_get_property(struct extcon_dev *edev, unsigned int id,
                                unsigned int prop,
                                union extcon_property_value *prop_val)
{
        struct extcon_cable *cable;
        unsigned long flags;
        int index, ret = 0;

        *prop_val = (union extcon_property_value)(0);

        if (!edev)
                return -EINVAL;

        /* Check whether the property is supported or not */
        if (!is_extcon_property_supported(id, prop))
                return -EINVAL;

        /* Find the cable index of external connector by using id */
        index = find_cable_index_by_id(edev, id);
        if (index < 0)
                return index;

        spin_lock_irqsave(&edev->lock, flags);

        /* Check whether the property is available or not. */
        if (!is_extcon_property_capability(edev, id, index, prop)) {
                spin_unlock_irqrestore(&edev->lock, flags);
                return -EPERM;
        }

        /*
         * Check whether the external connector is attached.
         * If external connector is detached, the user can not
         * get the property value.
         */
        if (!is_extcon_attached(edev, index)) {
                spin_unlock_irqrestore(&edev->lock, flags);
                return 0;
        }

        cable = &edev->cables[index];

        /* Get the property value according to extcon type */
        switch (prop) {
        case EXTCON_PROP_USB_MIN ... EXTCON_PROP_USB_MAX:
                *prop_val = cable->usb_propval[prop - EXTCON_PROP_USB_MIN];
                break;
        case EXTCON_PROP_CHG_MIN ... EXTCON_PROP_CHG_MAX:
                *prop_val = cable->chg_propval[prop - EXTCON_PROP_CHG_MIN];
                break;
        case EXTCON_PROP_JACK_MIN ... EXTCON_PROP_JACK_MAX:
                *prop_val = cable->jack_propval[prop - EXTCON_PROP_JACK_MIN];
                break;
        case EXTCON_PROP_DISP_MIN ... EXTCON_PROP_DISP_MAX:
                *prop_val = cable->disp_propval[prop - EXTCON_PROP_DISP_MIN];
                break;
        default:
                ret = -EINVAL;
                break;
        }

        spin_unlock_irqrestore(&edev->lock, flags);

        return ret;
}
EXPORT_SYMBOL_GPL(extcon_get_property);

/**
 * extcon_set_property() - Set the property value of a specific cable.
 * @edev:               the extcon device that has the cable.
 * @id:                 the unique id of each external connector
 *                      in extcon enumeration.
 * @prop:               the property id among enum extcon_property.
 * @prop_val:           the pointer including the new value of property.
 *
 * The each property should be included in the list of supported properties
 * according to the type of external connectors.
 *
 * Returns 0 if success or error number if fail
 */
int extcon_set_property(struct extcon_dev *edev, unsigned int id,
                                unsigned int prop,
                                union extcon_property_value prop_val)
{
        struct extcon_cable *cable;
        unsigned long flags;
        int index, ret = 0;

        if (!edev)
                return -EINVAL;

        /* Check whether the property is supported or not */
        if (!is_extcon_property_supported(id, prop))
                return -EINVAL;

        /* Find the cable index of external connector by using id */
        index = find_cable_index_by_id(edev, id);
        if (index < 0)
                return index;

        spin_lock_irqsave(&edev->lock, flags);

        /* Check whether the property is available or not. */
        if (!is_extcon_property_capability(edev, id, index, prop)) {
                spin_unlock_irqrestore(&edev->lock, flags);
                return -EPERM;
        }

        cable = &edev->cables[index];

        /* Set the property value according to extcon type */
        switch (prop) {
        case EXTCON_PROP_USB_MIN ... EXTCON_PROP_USB_MAX:
                cable->usb_propval[prop - EXTCON_PROP_USB_MIN] = prop_val;
                break;
        case EXTCON_PROP_CHG_MIN ... EXTCON_PROP_CHG_MAX:
                cable->chg_propval[prop - EXTCON_PROP_CHG_MIN] = prop_val;
                break;
        case EXTCON_PROP_JACK_MIN ... EXTCON_PROP_JACK_MAX:
                cable->jack_propval[prop - EXTCON_PROP_JACK_MIN] = prop_val;
                break;
        case EXTCON_PROP_DISP_MIN ... EXTCON_PROP_DISP_MAX:
                cable->disp_propval[prop - EXTCON_PROP_DISP_MIN] = prop_val;
                break;
        default:
                ret = -EINVAL;
                break;
        }

        spin_unlock_irqrestore(&edev->lock, flags);

        return ret;
}
EXPORT_SYMBOL_GPL(extcon_set_property);

/**
 * extcon_set_property_sync() - Set the property value of a specific cable
                        with a notification.
 * @prop_val:           the pointer including the new value of property.
 *
 * When setting the property value of external connector, the external connector
 * should be attached. The each property should be included in the list of
 * supported properties according to the type of external connectors.
 *
 * Returns 0 if success or error number if fail
 */
int extcon_set_property_sync(struct extcon_dev *edev, unsigned int id,
                                unsigned int prop,
                                union extcon_property_value prop_val)
{
        int ret;

        ret = extcon_set_property(edev, id, prop, prop_val);
        if (ret < 0)
                return ret;

        return extcon_sync(edev, id);
}
EXPORT_SYMBOL_GPL(extcon_set_property_sync);

/**
 * extcon_get_property_capability() - Get the capability of property
 *                      of an external connector.
 * @edev:               the extcon device that has the cable.
 * @id:                 the unique id of each external connector
 *                      in extcon enumeration.
 * @prop:               the property id among enum extcon_property.
 *
 * Returns 1 if the property is available or 0 if not available.
 */
int extcon_get_property_capability(struct extcon_dev *edev, unsigned int id,
                                        unsigned int prop)
{
        int index;

        if (!edev)
                return -EINVAL;

        /* Check whether the property is supported or not */
        if (!is_extcon_property_supported(id, prop))
                return -EINVAL;

        /* Find the cable index of external connector by using id */
        index = find_cable_index_by_id(edev, id);
        if (index < 0)
                return index;

        return is_extcon_property_capability(edev, id, index, prop);
}
EXPORT_SYMBOL_GPL(extcon_get_property_capability);

/**
 * extcon_set_property_capability() - Set the capability of a property
 *                      of an external connector.
 * @edev:               the extcon device that has the cable.
 * @id:                 the unique id of each external connector
 *                      in extcon enumeration.
 * @prop:               the property id among enum extcon_property.
 *
 * This function set the capability of a property for an external connector
 * to mark the bit in capability bitmap which mean the available state of
 * a property.
 *
 * Returns 0 if success or error number if fail
 */
int extcon_set_property_capability(struct extcon_dev *edev, unsigned int id,
                                        unsigned int prop)
{
        struct extcon_cable *cable;
        int index, type, ret = 0;

        if (!edev)
                return -EINVAL;

        /* Check whether the property is supported or not. */
        if (!is_extcon_property_supported(id, prop))
                return -EINVAL;

        /* Find the cable index of external connector by using id. */
        index = find_cable_index_by_id(edev, id);
        if (index < 0)
                return index;

        type = get_extcon_type(prop);
        if (type < 0)
                return type;

        cable = &edev->cables[index];

        switch (type) {
        case EXTCON_TYPE_USB:
                __set_bit(prop - EXTCON_PROP_USB_MIN, cable->usb_bits);
                break;
        case EXTCON_TYPE_CHG:
                __set_bit(prop - EXTCON_PROP_CHG_MIN, cable->chg_bits);
                break;
        case EXTCON_TYPE_JACK:
                __set_bit(prop - EXTCON_PROP_JACK_MIN, cable->jack_bits);
                break;
        case EXTCON_TYPE_DISP:
                __set_bit(prop - EXTCON_PROP_DISP_MIN, cable->disp_bits);
                break;
        default:
                ret = -EINVAL;
        }

        return ret;
}
EXPORT_SYMBOL_GPL(extcon_set_property_capability);

/**
 * 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_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 = -EINVAL;

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

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

        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);
        if (idx < 0)
                return idx;

        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);

/**
 * 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);

#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_dbg(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_dbg(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);
                        of_node_put(node);
                        return edev;
                }
        }
        mutex_unlock(&extcon_dev_list_lock);
        of_node_put(node);

        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");