/*
 * drivers/usb/core/sysfs.c
 *
 * (C) Copyright 2002 David Brownell
 * (C) Copyright 2002,2004 Greg Kroah-Hartman
 * (C) Copyright 2002,2004 IBM Corp.
 *
 * All of the sysfs file attributes for usb devices and interfaces.
 *
 */


#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/usb.h>
#include <linux/usb/quirks.h>
#include "usb.h"

/* Active configuration fields */
#define usb_actconfig_show(field, multiplier, format_string)            \
static ssize_t  show_##field(struct device *dev,                        \
                struct device_attribute *attr, char *buf)               \
{                                                                       \
        struct usb_device *udev;                                        \
        struct usb_host_config *actconfig;                              \
                                                                        \
        udev = to_usb_device(dev);                                      \
        actconfig = udev->actconfig;                                    \
        if (actconfig)                                                  \
                return sprintf(buf, format_string,                      \
                                actconfig->desc.field * multiplier);    \
        else                                                            \
                return 0;                                               \
}                                                                       \

#define usb_actconfig_attr(field, multiplier, format_string)            \
usb_actconfig_show(field, multiplier, format_string)                    \
static DEVICE_ATTR(field, S_IRUGO, show_##field, NULL);

usb_actconfig_attr(bNumInterfaces, 1, "%2d\n")
usb_actconfig_attr(bmAttributes, 1, "%2x\n")
usb_actconfig_attr(bMaxPower, 2, "%3dmA\n")

static ssize_t show_configuration_string(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct usb_device *udev;
        struct usb_host_config *actconfig;

        udev = to_usb_device(dev);
        actconfig = udev->actconfig;
        if ((!actconfig) || (!actconfig->string))
                return 0;
        return sprintf(buf, "%s\n", actconfig->string);
}
static DEVICE_ATTR(configuration, S_IRUGO, show_configuration_string, NULL);

/* configuration value is always present, and r/w */
usb_actconfig_show(bConfigurationValue, 1, "%u\n");

static ssize_t
set_bConfigurationValue(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
{
        struct usb_device       *udev = to_usb_device(dev);
        int                     config, value;

        if (sscanf(buf, "%d", &config) != 1 || config < -1 || config > 255)
                return -EINVAL;
        usb_lock_device(udev);
        value = usb_set_configuration(udev, config);
        usb_unlock_device(udev);
        return (value < 0) ? value : count;
}

static DEVICE_ATTR_IGNORE_LOCKDEP(bConfigurationValue, S_IRUGO | S_IWUSR,
                show_bConfigurationValue, set_bConfigurationValue);

/* String fields */
#define usb_string_attr(name)                                           \
static ssize_t  show_##name(struct device *dev,                         \
                struct device_attribute *attr, char *buf)               \
{                                                                       \
        struct usb_device *udev;                                        \
        int retval;                                                     \
                                                                        \
        udev = to_usb_device(dev);                                      \
        usb_lock_device(udev);                                          \
        retval = sprintf(buf, "%s\n", udev->name);                      \
        usb_unlock_device(udev);                                        \
        return retval;                                                  \
}                                                                       \
static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL);

usb_string_attr(product);
usb_string_attr(manufacturer);
usb_string_attr(serial);

static ssize_t
show_speed(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct usb_device *udev;
        char *speed;

        udev = to_usb_device(dev);

        switch (udev->speed) {
        case USB_SPEED_LOW:
                speed = "1.5";
                break;
        case USB_SPEED_UNKNOWN:
        case USB_SPEED_FULL:
                speed = "12";
                break;
        case USB_SPEED_HIGH:
                speed = "480";
                break;
        case USB_SPEED_WIRELESS:
                speed = "480";
                break;
        case USB_SPEED_SUPER:
                speed = "5000";
                break;
        default:
                speed = "unknown";
        }
        return sprintf(buf, "%s\n", speed);
}
static DEVICE_ATTR(speed, S_IRUGO, show_speed, NULL);

static ssize_t
show_busnum(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct usb_device *udev;

        udev = to_usb_device(dev);
        return sprintf(buf, "%d\n", udev->bus->busnum);
}
static DEVICE_ATTR(busnum, S_IRUGO, show_busnum, NULL);

static ssize_t
show_devnum(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct usb_device *udev;

        udev = to_usb_device(dev);
        return sprintf(buf, "%d\n", udev->devnum);
}
static DEVICE_ATTR(devnum, S_IRUGO, show_devnum, NULL);

static ssize_t
show_devpath(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct usb_device *udev;

        udev = to_usb_device(dev);
        return sprintf(buf, "%s\n", udev->devpath);
}
static DEVICE_ATTR(devpath, S_IRUGO, show_devpath, NULL);

static ssize_t
show_version(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct usb_device *udev;
        u16 bcdUSB;

        udev = to_usb_device(dev);
        bcdUSB = le16_to_cpu(udev->descriptor.bcdUSB);
        return sprintf(buf, "%2x.%02x\n", bcdUSB >> 8, bcdUSB & 0xff);
}
static DEVICE_ATTR(version, S_IRUGO, show_version, NULL);

static ssize_t
show_maxchild(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct usb_device *udev;

        udev = to_usb_device(dev);
        return sprintf(buf, "%d\n", udev->maxchild);
}
static DEVICE_ATTR(maxchild, S_IRUGO, show_maxchild, NULL);

static ssize_t
show_quirks(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct usb_device *udev;

        udev = to_usb_device(dev);
        return sprintf(buf, "0x%x\n", udev->quirks);
}
static DEVICE_ATTR(quirks, S_IRUGO, show_quirks, NULL);

static ssize_t
show_avoid_reset_quirk(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct usb_device *udev;

        udev = to_usb_device(dev);
        return sprintf(buf, "%d\n", !!(udev->quirks & USB_QUIRK_RESET));
}

static ssize_t
set_avoid_reset_quirk(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
{
        struct usb_device       *udev = to_usb_device(dev);
        int                     val;

        if (sscanf(buf, "%d", &val) != 1 || val < 0 || val > 1)
                return -EINVAL;
        usb_lock_device(udev);
        if (val)
                udev->quirks |= USB_QUIRK_RESET;
        else
                udev->quirks &= ~USB_QUIRK_RESET;
        usb_unlock_device(udev);
        return count;
}

static DEVICE_ATTR(avoid_reset_quirk, S_IRUGO | S_IWUSR,
                show_avoid_reset_quirk, set_avoid_reset_quirk);

static ssize_t
show_urbnum(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct usb_device *udev;

        udev = to_usb_device(dev);
        return sprintf(buf, "%d\n", atomic_read(&udev->urbnum));
}
static DEVICE_ATTR(urbnum, S_IRUGO, show_urbnum, NULL);

static ssize_t
show_removable(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct usb_device *udev;
        char *state;

        udev = to_usb_device(dev);

        switch (udev->removable) {
        case USB_DEVICE_REMOVABLE:
                state = "removable";
                break;
        case USB_DEVICE_FIXED:
                state = "fixed";
                break;
        default:
                state = "unknown";
        }

        return sprintf(buf, "%s\n", state);
}
static DEVICE_ATTR(removable, S_IRUGO, show_removable, NULL);

static ssize_t
show_ltm_capable(struct device *dev, struct device_attribute *attr, char *buf)
{
        if (usb_device_supports_ltm(to_usb_device(dev)))
                return sprintf(buf, "%s\n", "yes");
        return sprintf(buf, "%s\n", "no");
}
static DEVICE_ATTR(ltm_capable, S_IRUGO, show_ltm_capable, NULL);

#ifdef  CONFIG_PM

static ssize_t
show_persist(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct usb_device *udev = to_usb_device(dev);

        return sprintf(buf, "%d\n", udev->persist_enabled);
}

static ssize_t
set_persist(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
{
        struct usb_device *udev = to_usb_device(dev);
        int value;

        /* Hubs are always enabled for USB_PERSIST */
        if (udev->descriptor.bDeviceClass == USB_CLASS_HUB)
                return -EPERM;

        if (sscanf(buf, "%d", &value) != 1)
                return -EINVAL;

        usb_lock_device(udev);
        udev->persist_enabled = !!value;
        usb_unlock_device(udev);
        return count;
}

static DEVICE_ATTR(persist, S_IRUGO | S_IWUSR, show_persist, set_persist);

static int add_persist_attributes(struct device *dev)
{
        int rc = 0;

        if (is_usb_device(dev)) {
                struct usb_device *udev = to_usb_device(dev);

                /* Hubs are automatically enabled for USB_PERSIST,
                 * no point in creating the attribute file.
                 */
                if (udev->descriptor.bDeviceClass != USB_CLASS_HUB)
                        rc = sysfs_add_file_to_group(&dev->kobj,
                                        &dev_attr_persist.attr,
                                        power_group_name);
        }
        return rc;
}

static void remove_persist_attributes(struct device *dev)
{
        sysfs_remove_file_from_group(&dev->kobj,
                        &dev_attr_persist.attr,
                        power_group_name);
}
#else

#define add_persist_attributes(dev)     0
#define remove_persist_attributes(dev)  do {} while (0)

#endif  /* CONFIG_PM */

#ifdef  CONFIG_USB_SUSPEND

static ssize_t
show_connected_duration(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct usb_device *udev = to_usb_device(dev);

        return sprintf(buf, "%u\n",
                        jiffies_to_msecs(jiffies - udev->connect_time));
}

static DEVICE_ATTR(connected_duration, S_IRUGO, show_connected_duration, NULL);

/*
 * If the device is resumed, the last time the device was suspended has
 * been pre-subtracted from active_duration.  We add the current time to
 * get the duration that the device was actually active.
 *
 * If the device is suspended, the active_duration is up-to-date.
 */
static ssize_t
show_active_duration(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct usb_device *udev = to_usb_device(dev);
        int duration;

        if (udev->state != USB_STATE_SUSPENDED)
                duration = jiffies_to_msecs(jiffies + udev->active_duration);
        else
                duration = jiffies_to_msecs(udev->active_duration);
        return sprintf(buf, "%u\n", duration);
}

static DEVICE_ATTR(active_duration, S_IRUGO, show_active_duration, NULL);

static ssize_t
show_autosuspend(struct device *dev, struct device_attribute *attr, char *buf)
{
        return sprintf(buf, "%d\n", dev->power.autosuspend_delay / 1000);
}

static ssize_t
set_autosuspend(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
{
        int value;

        if (sscanf(buf, "%d", &value) != 1 || value >= INT_MAX/1000 ||
                        value <= -INT_MAX/1000)
                return -EINVAL;

        pm_runtime_set_autosuspend_delay(dev, value * 1000);
        return count;
}

static DEVICE_ATTR(autosuspend, S_IRUGO | S_IWUSR,
                show_autosuspend, set_autosuspend);

static const char on_string[] = "on";
static const char auto_string[] = "auto";

static void warn_level(void) {
        static int level_warned;

        if (!level_warned) {
                level_warned = 1;
                printk(KERN_WARNING "WARNING! power/level is deprecated; "
                                "use power/control instead\n");
        }
}

static ssize_t
show_level(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct usb_device *udev = to_usb_device(dev);
        const char *p = auto_string;

        warn_level();
        if (udev->state != USB_STATE_SUSPENDED && !udev->dev.power.runtime_auto)
                p = on_string;
        return sprintf(buf, "%s\n", p);
}

static ssize_t
set_level(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
{
        struct usb_device *udev = to_usb_device(dev);
        int len = count;
        char *cp;
        int rc = count;

        warn_level();
        cp = memchr(buf, '\n', count);
        if (cp)
                len = cp - buf;

        usb_lock_device(udev);

        if (len == sizeof on_string - 1 &&
                        strncmp(buf, on_string, len) == 0)
                usb_disable_autosuspend(udev);

        else if (len == sizeof auto_string - 1 &&
                        strncmp(buf, auto_string, len) == 0)
                usb_enable_autosuspend(udev);

        else
                rc = -EINVAL;

        usb_unlock_device(udev);
        return rc;
}

static DEVICE_ATTR(level, S_IRUGO | S_IWUSR, show_level, set_level);

static ssize_t
show_usb2_hardware_lpm(struct device *dev, struct device_attribute *attr,
                                char *buf)
{
        struct usb_device *udev = to_usb_device(dev);
        const char *p;

        if (udev->usb2_hw_lpm_enabled == 1)
                p = "enabled";
        else
                p = "disabled";

        return sprintf(buf, "%s\n", p);
}

static ssize_t
set_usb2_hardware_lpm(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
{
        struct usb_device *udev = to_usb_device(dev);
        bool value;
        int ret;

        usb_lock_device(udev);

        ret = strtobool(buf, &value);

        if (!ret)
                ret = usb_set_usb2_hardware_lpm(udev, value);

        usb_unlock_device(udev);

        if (!ret)
                return count;

        return ret;
}

static DEVICE_ATTR(usb2_hardware_lpm, S_IRUGO | S_IWUSR, show_usb2_hardware_lpm,
                        set_usb2_hardware_lpm);

static struct attribute *usb2_hardware_lpm_attr[] = {
        &dev_attr_usb2_hardware_lpm.attr,
        NULL,
};
static struct attribute_group usb2_hardware_lpm_attr_group = {
        .name   = power_group_name,
        .attrs  = usb2_hardware_lpm_attr,
};

static struct attribute *power_attrs[] = {
        &dev_attr_autosuspend.attr,
        &dev_attr_level.attr,
        &dev_attr_connected_duration.attr,
        &dev_attr_active_duration.attr,
        NULL,
};
static struct attribute_group power_attr_group = {
        .name   = power_group_name,
        .attrs  = power_attrs,
};

static int add_power_attributes(struct device *dev)
{
        int rc = 0;

        if (is_usb_device(dev)) {
                struct usb_device *udev = to_usb_device(dev);
                rc = sysfs_merge_group(&dev->kobj, &power_attr_group);
                if (udev->usb2_hw_lpm_capable == 1)
                        rc = sysfs_merge_group(&dev->kobj,
                                        &usb2_hardware_lpm_attr_group);
        }

        return rc;
}

static void remove_power_attributes(struct device *dev)
{
        sysfs_unmerge_group(&dev->kobj, &usb2_hardware_lpm_attr_group);
        sysfs_unmerge_group(&dev->kobj, &power_attr_group);
}

#else

#define add_power_attributes(dev)       0
#define remove_power_attributes(dev)    do {} while (0)

#endif  /* CONFIG_USB_SUSPEND */


/* Descriptor fields */
#define usb_descriptor_attr_le16(field, format_string)                  \
static ssize_t                                                          \
show_##field(struct device *dev, struct device_attribute *attr, \
                char *buf)                                              \
{                                                                       \
        struct usb_device *udev;                                        \
                                                                        \
        udev = to_usb_device(dev);                                      \
        return sprintf(buf, format_string,                              \
                        le16_to_cpu(udev->descriptor.field));           \
}                                                                       \
static DEVICE_ATTR(field, S_IRUGO, show_##field, NULL);

usb_descriptor_attr_le16(idVendor, "%04x\n")
usb_descriptor_attr_le16(idProduct, "%04x\n")
usb_descriptor_attr_le16(bcdDevice, "%04x\n")

#define usb_descriptor_attr(field, format_string)                       \
static ssize_t                                                          \
show_##field(struct device *dev, struct device_attribute *attr, \
                char *buf)                                              \
{                                                                       \
        struct usb_device *udev;                                        \
                                                                        \
        udev = to_usb_device(dev);                                      \
        return sprintf(buf, format_string, udev->descriptor.field);     \
}                                                                       \
static DEVICE_ATTR(field, S_IRUGO, show_##field, NULL);

usb_descriptor_attr(bDeviceClass, "%02x\n")
usb_descriptor_attr(bDeviceSubClass, "%02x\n")
usb_descriptor_attr(bDeviceProtocol, "%02x\n")
usb_descriptor_attr(bNumConfigurations, "%d\n")
usb_descriptor_attr(bMaxPacketSize0, "%d\n")



/* show if the device is authorized (1) or not (0) */
static ssize_t usb_dev_authorized_show(struct device *dev,
                                       struct device_attribute *attr,
                                       char *buf)
{
        struct usb_device *usb_dev = to_usb_device(dev);
        return snprintf(buf, PAGE_SIZE, "%u\n", usb_dev->authorized);
}


/*
 * Authorize a device to be used in the system
 *
 * Writing a 0 deauthorizes the device, writing a 1 authorizes it.
 */
static ssize_t usb_dev_authorized_store(struct device *dev,
                                        struct device_attribute *attr,
                                        const char *buf, size_t size)
{
        ssize_t result;
        struct usb_device *usb_dev = to_usb_device(dev);
        unsigned val;
        result = sscanf(buf, "%u\n", &val);
        if (result != 1)
                result = -EINVAL;
        else if (val == 0)
                result = usb_deauthorize_device(usb_dev);
        else
                result = usb_authorize_device(usb_dev);
        return result < 0? result : size;
}

static DEVICE_ATTR_IGNORE_LOCKDEP(authorized, 0644,
            usb_dev_authorized_show, usb_dev_authorized_store);

/* "Safely remove a device" */
static ssize_t usb_remove_store(struct device *dev,
                struct device_attribute *attr,
                const char *buf, size_t count)
{
        struct usb_device *udev = to_usb_device(dev);
        int rc = 0;

        usb_lock_device(udev);
        if (udev->state != USB_STATE_NOTATTACHED) {

                /* To avoid races, first unconfigure and then remove */
                usb_set_configuration(udev, -1);
                rc = usb_remove_device(udev);
        }
        if (rc == 0)
                rc = count;
        usb_unlock_device(udev);
        return rc;
}
static DEVICE_ATTR_IGNORE_LOCKDEP(remove, 0200, NULL, usb_remove_store);


static struct attribute *dev_attrs[] = {
        /* current configuration's attributes */
        &dev_attr_configuration.attr,
        &dev_attr_bNumInterfaces.attr,
        &dev_attr_bConfigurationValue.attr,
        &dev_attr_bmAttributes.attr,
        &dev_attr_bMaxPower.attr,
        /* device attributes */
        &dev_attr_urbnum.attr,
        &dev_attr_idVendor.attr,
        &dev_attr_idProduct.attr,
        &dev_attr_bcdDevice.attr,
        &dev_attr_bDeviceClass.attr,
        &dev_attr_bDeviceSubClass.attr,
        &dev_attr_bDeviceProtocol.attr,
        &dev_attr_bNumConfigurations.attr,
        &dev_attr_bMaxPacketSize0.attr,
        &dev_attr_speed.attr,
        &dev_attr_busnum.attr,
        &dev_attr_devnum.attr,
        &dev_attr_devpath.attr,
        &dev_attr_version.attr,
        &dev_attr_maxchild.attr,
        &dev_attr_quirks.attr,
        &dev_attr_avoid_reset_quirk.attr,
        &dev_attr_authorized.attr,
        &dev_attr_remove.attr,
        &dev_attr_removable.attr,
        &dev_attr_ltm_capable.attr,
        NULL,
};
static struct attribute_group dev_attr_grp = {
        .attrs = dev_attrs,
};

/* When modifying this list, be sure to modify dev_string_attrs_are_visible()
 * accordingly.
 */
static struct attribute *dev_string_attrs[] = {
        &dev_attr_manufacturer.attr,
        &dev_attr_product.attr,
        &dev_attr_serial.attr,
        NULL
};

static umode_t dev_string_attrs_are_visible(struct kobject *kobj,
                struct attribute *a, int n)
{
        struct device *dev = container_of(kobj, struct device, kobj);
        struct usb_device *udev = to_usb_device(dev);

        if (a == &dev_attr_manufacturer.attr) {
                if (udev->manufacturer == NULL)
                        return 0;
        } else if (a == &dev_attr_product.attr) {
                if (udev->product == NULL)
                        return 0;
        } else if (a == &dev_attr_serial.attr) {
                if (udev->serial == NULL)
                        return 0;
        }
        return a->mode;
}

static struct attribute_group dev_string_attr_grp = {
        .attrs =        dev_string_attrs,
        .is_visible =   dev_string_attrs_are_visible,
};

const struct attribute_group *usb_device_groups[] = {
        &dev_attr_grp,
        &dev_string_attr_grp,
        NULL
};

/* Binary descriptors */

static ssize_t
read_descriptors(struct file *filp, struct kobject *kobj,
                struct bin_attribute *attr,
                char *buf, loff_t off, size_t count)
{
        struct device *dev = container_of(kobj, struct device, kobj);
        struct usb_device *udev = to_usb_device(dev);
        size_t nleft = count;
        size_t srclen, n;
        int cfgno;
        void *src;

        /* The binary attribute begins with the device descriptor.
         * Following that are the raw descriptor entries for all the
         * configurations (config plus subsidiary descriptors).
         */
        for (cfgno = -1; cfgno < udev->descriptor.bNumConfigurations &&
                        nleft > 0; ++cfgno) {
                if (cfgno < 0) {
                        src = &udev->descriptor;
                        srclen = sizeof(struct usb_device_descriptor);
                } else {
                        src = udev->rawdescriptors[cfgno];
                        srclen = __le16_to_cpu(udev->config[cfgno].desc.
                                        wTotalLength);
                }
                if (off < srclen) {
                        n = min(nleft, srclen - (size_t) off);
                        memcpy(buf, src + off, n);
                        nleft -= n;
                        buf += n;
                        off = 0;
                } else {
                        off -= srclen;
                }
        }
        return count - nleft;
}

static struct bin_attribute dev_bin_attr_descriptors = {
        .attr = {.name = "descriptors", .mode = 0444},
        .read = read_descriptors,
        .size = 18 + 65535,     /* dev descr + max-size raw descriptor */
};

int usb_create_sysfs_dev_files(struct usb_device *udev)
{
        struct device *dev = &udev->dev;
        int retval;

        retval = device_create_bin_file(dev, &dev_bin_attr_descriptors);
        if (retval)
                goto error;

        retval = add_persist_attributes(dev);
        if (retval)
                goto error;

        retval = add_power_attributes(dev);
        if (retval)
                goto error;
        return retval;
error:
        usb_remove_sysfs_dev_files(udev);
        return retval;
}

void usb_remove_sysfs_dev_files(struct usb_device *udev)
{
        struct device *dev = &udev->dev;

        remove_power_attributes(dev);
        remove_persist_attributes(dev);
        device_remove_bin_file(dev, &dev_bin_attr_descriptors);
}

/* Interface Accociation Descriptor fields */
#define usb_intf_assoc_attr(field, format_string)                       \
static ssize_t                                                          \
show_iad_##field(struct device *dev, struct device_attribute *attr,     \
                char *buf)                                              \
{                                                                       \
        struct usb_interface *intf = to_usb_interface(dev);             \
                                                                        \
        return sprintf(buf, format_string,                              \
                        intf->intf_assoc->field);                       \
}                                                                       \
static DEVICE_ATTR(iad_##field, S_IRUGO, show_iad_##field, NULL);

usb_intf_assoc_attr(bFirstInterface, "%02x\n")
usb_intf_assoc_attr(bInterfaceCount, "%02d\n")
usb_intf_assoc_attr(bFunctionClass, "%02x\n")
usb_intf_assoc_attr(bFunctionSubClass, "%02x\n")
usb_intf_assoc_attr(bFunctionProtocol, "%02x\n")

/* Interface fields */
#define usb_intf_attr(field, format_string)                             \
static ssize_t                                                          \
show_##field(struct device *dev, struct device_attribute *attr, \
                char *buf)                                              \
{                                                                       \
        struct usb_interface *intf = to_usb_interface(dev);             \
                                                                        \
        return sprintf(buf, format_string,                              \
                        intf->cur_altsetting->desc.field);              \
}                                                                       \
static DEVICE_ATTR(field, S_IRUGO, show_##field, NULL);

usb_intf_attr(bInterfaceNumber, "%02x\n")
usb_intf_attr(bAlternateSetting, "%2d\n")
usb_intf_attr(bNumEndpoints, "%02x\n")
usb_intf_attr(bInterfaceClass, "%02x\n")
usb_intf_attr(bInterfaceSubClass, "%02x\n")
usb_intf_attr(bInterfaceProtocol, "%02x\n")

static ssize_t show_interface_string(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct usb_interface *intf;
        char *string;

        intf = to_usb_interface(dev);
        string = intf->cur_altsetting->string;
        barrier();              /* The altsetting might change! */

        if (!string)
                return 0;
        return sprintf(buf, "%s\n", string);
}
static DEVICE_ATTR(interface, S_IRUGO, show_interface_string, NULL);

static ssize_t show_modalias(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct usb_interface *intf;
        struct usb_device *udev;
        struct usb_host_interface *alt;

        intf = to_usb_interface(dev);
        udev = interface_to_usbdev(intf);
        alt = intf->cur_altsetting;

        return sprintf(buf, "usb:v%04Xp%04Xd%04Xdc%02Xdsc%02Xdp%02X"
                        "ic%02Xisc%02Xip%02Xin%02X\n",
                        le16_to_cpu(udev->descriptor.idVendor),
                        le16_to_cpu(udev->descriptor.idProduct),
                        le16_to_cpu(udev->descriptor.bcdDevice),
                        udev->descriptor.bDeviceClass,
                        udev->descriptor.bDeviceSubClass,
                        udev->descriptor.bDeviceProtocol,
                        alt->desc.bInterfaceClass,
                        alt->desc.bInterfaceSubClass,
                        alt->desc.bInterfaceProtocol,
                        alt->desc.bInterfaceNumber);
}
static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);

static ssize_t show_supports_autosuspend(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct usb_interface *intf;
        struct usb_device *udev;
        int ret;

        intf = to_usb_interface(dev);
        udev = interface_to_usbdev(intf);

        usb_lock_device(udev);
        /* Devices will be autosuspended even when an interface isn't claimed */
        if (!intf->dev.driver ||
                        to_usb_driver(intf->dev.driver)->supports_autosuspend)
                ret = sprintf(buf, "%u\n", 1);
        else
                ret = sprintf(buf, "%u\n", 0);
        usb_unlock_device(udev);

        return ret;
}
static DEVICE_ATTR(supports_autosuspend, S_IRUGO, show_supports_autosuspend, NULL);

static struct attribute *intf_attrs[] = {
        &dev_attr_bInterfaceNumber.attr,
        &dev_attr_bAlternateSetting.attr,
        &dev_attr_bNumEndpoints.attr,
        &dev_attr_bInterfaceClass.attr,
        &dev_attr_bInterfaceSubClass.attr,
        &dev_attr_bInterfaceProtocol.attr,
        &dev_attr_modalias.attr,
        &dev_attr_supports_autosuspend.attr,
        NULL,
};
static struct attribute_group intf_attr_grp = {
        .attrs = intf_attrs,
};

static struct attribute *intf_assoc_attrs[] = {
        &dev_attr_iad_bFirstInterface.attr,
        &dev_attr_iad_bInterfaceCount.attr,
        &dev_attr_iad_bFunctionClass.attr,
        &dev_attr_iad_bFunctionSubClass.attr,
        &dev_attr_iad_bFunctionProtocol.attr,
        NULL,
};

static umode_t intf_assoc_attrs_are_visible(struct kobject *kobj,
                struct attribute *a, int n)
{
        struct device *dev = container_of(kobj, struct device, kobj);
        struct usb_interface *intf = to_usb_interface(dev);

        if (intf->intf_assoc == NULL)
                return 0;
        return a->mode;
}

static struct attribute_group intf_assoc_attr_grp = {
        .attrs =        intf_assoc_attrs,
        .is_visible =   intf_assoc_attrs_are_visible,
};

const struct attribute_group *usb_interface_groups[] = {
        &intf_attr_grp,
        &intf_assoc_attr_grp,
        NULL
};

void usb_create_sysfs_intf_files(struct usb_interface *intf)
{
        struct usb_device *udev = interface_to_usbdev(intf);
        struct usb_host_interface *alt = intf->cur_altsetting;

        if (intf->sysfs_files_created || intf->unregistering)
                return;

        if (!alt->string && !(udev->quirks & USB_QUIRK_CONFIG_INTF_STRINGS))
                alt->string = usb_cache_string(udev, alt->desc.iInterface);
        if (alt->string && device_create_file(&intf->dev, &dev_attr_interface))
                ;       /* We don't actually care if the function fails. */
        intf->sysfs_files_created = 1;
}

void usb_remove_sysfs_intf_files(struct usb_interface *intf)
{
        if (!intf->sysfs_files_created)
                return;

        device_remove_file(&intf->dev, &dev_attr_interface);
        intf->sysfs_files_created = 0;
}