extcon-class.c

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/*
 *  drivers/extcon/extcon_class.c
 *
 *  External connector (extcon) class driver
 *
 * Copyright (C) 2012 Samsung Electronics
 * Author: Donggeun Kim <[email protected]>
 * Author: MyungJoo Ham <[email protected]>
 *
 * based on android/drivers/switch/switch_class.c
 * Copyright (C) 2008 Google, Inc.
 * Author: Mike Lockwood <[email protected]>
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
*/

#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);

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;
}

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);

int extcon_set_state(struct extcon_dev *edev, u32 state)
{
    return extcon_update_state(edev, 0xffffffff, state);
}
EXPORT_SYMBOL_GPL(extcon_set_state);

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);

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_);

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);

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_);

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);

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;
}

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 -ENODEV;

        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;
    }
}

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);
}

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);

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)
{
}

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);

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 <[email protected]>");
MODULE_AUTHOR("Donggeun Kim <[email protected]>");
MODULE_AUTHOR("MyungJoo Ham <[email protected]>");
MODULE_DESCRIPTION("External connector (extcon) class driver");
MODULE_LICENSE("GPL");