drivers/hid/hid-core.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  HID support for Linux
 *
 *  Copyright (c) 1999 Andreas Gal
 *  Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
 *  Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
 *  Copyright (c) 2006-2012 Jiri Kosina
 */

/*
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/spinlock.h>
#include <asm/unaligned.h>
#include <asm/byteorder.h>
#include <linux/input.h>
#include <linux/wait.h>
#include <linux/vmalloc.h>
#include <linux/sched.h>
#include <linux/semaphore.h>

#include <linux/hid.h>
#include <linux/hiddev.h>
#include <linux/hid-debug.h>
#include <linux/hidraw.h>

#include "hid-ids.h"

/*
 * Version Information
 */

#define DRIVER_DESC "HID core driver"
#define HID_COLLECTION_SIZE_OF 2
#define HID_COMPLETE_USAGE_MASK 0xFFFF
#define HID_COMPLETE_USAGE_SHIFT_MASK 16
#define HID_ADD_USAGE_SIZE 2
#define HID_MAX_BUFFER_SIZE_SHIFT_MASK 3
#define HID_ITEM_UDATA_BYTE 1
#define HID_ITEM_UDATA_WORD 2
#define HID_ITEM_UDATA_DWORD 4
#define HID_ITEM_SDATA_BYTE 1
#define HID_ITEM_SDATA_WORD 2
#define HID_ITEM_SDATA_DWORD 4
#define HID_REPORT_SIZE 256
#define HID_OPEN_COLLECTION_TYPE_MASK 0XFF
#define HID_FETCH_ITEM_SHIFT_MASK_TWO 2
#define HID_FETCH_ITEM_SHIFT_MASK_FOUR 4
#define HID_FETCH_ITEM_SHIFT_BIT_MASK_THREE 3
#define HID_FETCH_ITEM_SHIFT_BIT_MASK_FIFTEEN 15
#define HID_FETCH_ITEM_SIZE_ZERO 0
#define HID_FETCH_ITEM_SIZE_ONE 1
#define HID_FETCH_ITEM_SIZE_TWO 2
#define HID_FETCH_ITEM_SIZE_THREE 3
#define HID_FETCH_ITEM_SIZE_FOUR 4
#define HID_SCAN_FEATURE_USAGE_REG_C5 0xff0000c5
#define HID_SCAN_FEATURE_USAGE_REG_C6 0xff0000c6
#define HID_REPORT_COUNT_SIZE_ONE 1
#define HID_GLOBAL_REPORT_SIZE 8
#define HID_GLOBAL_USAGE_PAGE_SHIFT_MASK 16
#define HID_UP_VENDOR_MASK 0x0001
#define HID_COLLECTION_TYPE_MASK 0xff
#define HID_MULTIPLIER_MAX 255
#define HID_BYTE_BIT_WIDTH 8
#define HID_WORD_BIT_WIDTH 16
#define HID_DWORD_BIT_WIDTH 32
#define HID_BYTE_BIT_MASK 0xff
#define HID_REPORT_SIEZE_MASK 3
#define HID_BYTE_CHUNK 7
#define HID_FETCH_ITEM_SIZE_WORD 2

int hid_debug = 0;
module_param_named(debug, hid_debug, int, 0600);
MODULE_PARM_DESC(debug, "toggle HID debugging messages");
EXPORT_SYMBOL_GPL(hid_debug);

static int hid_ignore_special_drivers = 0;
module_param_named(ignore_special_drivers, hid_ignore_special_drivers, int, 0600);
MODULE_PARM_DESC(ignore_special_drivers, "Ignore any special drivers and handle all devices by generic driver");

/*
 * Register a new report for a device.
 */

struct hid_report *hid_register_report(struct hid_device *device, unsigned int type, unsigned int id,
                                       unsigned int application)
{
    struct hid_report_enum *report_enum = device->report_enum + type;
    struct hid_report *report;

    if (id >= HID_MAX_IDS) {
        return NULL;
    }
    if (report_enum->report_id_hash[id]) {
        return report_enum->report_id_hash[id];
    }

    report = kzalloc(sizeof(struct hid_report), GFP_KERNEL);
    if (!report) {
        return NULL;
    }

    if (id != 0) {
        report_enum->numbered = 1;
    }

    report->id = id;
    report->type = type;
    report->size = 0;
    report->device = device;
    report->application = application;
    report_enum->report_id_hash[id] = report;

    list_add_tail(&report->list, &report_enum->report_list);

    return report;
}
EXPORT_SYMBOL_GPL(hid_register_report);

/*
 * Register a new field for this report.
 */

static struct hid_field *hid_register_field(struct hid_report *report, unsigned usages)
{
    struct hid_field *field;

    if (report->maxfield == HID_MAX_FIELDS) {
        return NULL;
    }

    field =
        kzalloc((sizeof(struct hid_field) + usages * sizeof(struct hid_usage) + usages * sizeof(unsigned)), GFP_KERNEL);
    if (!field) {
        return NULL;
    }

    field->index = report->maxfield++;
    report->field[field->index] = field;
    field->usage = (struct hid_usage *)(field + 1);
    field->value = (s32 *)(field->usage + usages);
    field->report = report;

    return field;
}

/*
 * Open a collection. The type/usage is pushed on the stack.
 */

static int open_collection(struct hid_parser *parser, unsigned type)
{
    struct hid_collection *collection;
    unsigned usage;
    int collection_index;

    usage = parser->local.usage[0];

    if (parser->collection_stack_ptr == parser->collection_stack_size) {
        unsigned int *collection_stack;
        unsigned int new_size = parser->collection_stack_size + HID_COLLECTION_STACK_SIZE;

        collection_stack = krealloc(parser->collection_stack, new_size * sizeof(unsigned int), GFP_KERNEL);
        if (!collection_stack) {
            return -ENOMEM;
        }

        parser->collection_stack = collection_stack;
        parser->collection_stack_size = new_size;
    }

    if (parser->device->maxcollection == parser->device->collection_size) {
        collection =
            kmalloc(array3_size(sizeof(struct hid_collection), parser->device->collection_size, HID_COLLECTION_SIZE_OF),
                    GFP_KERNEL);
        if (collection == NULL) {
            return -ENOMEM;
        }
        memcpy(collection, parser->device->collection, sizeof(struct hid_collection) * parser->device->collection_size);
        memset(collection + parser->device->collection_size, 0,
               sizeof(struct hid_collection) * parser->device->collection_size);
        kfree(parser->device->collection);
        parser->device->collection = collection;
        parser->device->collection_size *= HID_COLLECTION_SIZE_OF;
    }

    parser->collection_stack[parser->collection_stack_ptr++] = parser->device->maxcollection;

    collection_index = parser->device->maxcollection++;
    collection = parser->device->collection + collection_index;
    collection->type = type;
    collection->usage = usage;
    collection->level = parser->collection_stack_ptr - 1;
    collection->parent_idx = (collection->level == 0) ? -1 : parser->collection_stack[collection->level - 1];

    if (type == HID_COLLECTION_APPLICATION) {
        parser->device->maxapplication++;
    }

    return 0;
}

/*
 * Close a collection.
 */

static int close_collection(struct hid_parser *parser)
{
    if (!parser->collection_stack_ptr) {
        return -EINVAL;
    }
    parser->collection_stack_ptr--;
    return 0;
}

/*
 * Climb up the stack, search for the specified collection type
 * and return the usage.
 */

static unsigned hid_lookup_collection(struct hid_parser *parser, unsigned type)
{
    struct hid_collection *collection = parser->device->collection;
    int n;

    for (n = parser->collection_stack_ptr - 1; n >= 0; n--) {
        unsigned index = parser->collection_stack[n];
        if (collection[index].type == type) {
            return collection[index].usage;
        }
    }
    return 0; /* we know nothing about this usage type */
}

/*
 * Concatenate usage which defines 16 bits or less with the
 * currently defined usage page to form a 32 bit usage
 */

static void complete_usage(struct hid_parser *parser, unsigned int index)
{
    parser->local.usage[index] &= HID_COMPLETE_USAGE_MASK;
    parser->local.usage[index] |= (parser->global.usage_page & HID_COMPLETE_USAGE_MASK)
                                  << HID_COMPLETE_USAGE_SHIFT_MASK;
}

/*
 * Add a usage to the temporary parser table.
 */

static int hid_add_usage(struct hid_parser *parser, unsigned usage, u8 size)
{
    if (parser->local.usage_index >= HID_MAX_USAGES) {
        return -EPERM;
    }
    parser->local.usage[parser->local.usage_index] = usage;

    /*
     * If Usage item only includes usage id, concatenate it with
     * currently defined usage page
     */
    if (size <= HID_ADD_USAGE_SIZE) {
        complete_usage(parser, parser->local.usage_index);
    }

    parser->local.usage_size[parser->local.usage_index] = size;
    parser->local.collection_index[parser->local.usage_index] =
        parser->collection_stack_ptr ? parser->collection_stack[parser->collection_stack_ptr - 1] : 0;
    parser->local.usage_index++;
    return 0;
}

/*
 * Register a new field for this report.
 */

static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsigned flags)
{
    struct hid_report *report;
    struct hid_field *field;
    unsigned int usages;
    unsigned int offset;
    unsigned int i;
    unsigned int application;
    application = hid_lookup_collection(parser, HID_COLLECTION_APPLICATION);
    report = hid_register_report(parser->device, report_type, parser->global.report_id, application);
    if (!report) {
        return -EPERM;
    }
    /* Handle both signed and unsigned cases properly */
    if ((parser->global.logical_minimum < 0 && parser->global.logical_maximum < parser->global.logical_minimum) ||
        (parser->global.logical_minimum >= 0 &&
         (u32)parser->global.logical_maximum < (u32)parser->global.logical_minimum)) {
        return -EPERM;
    }
    offset = report->size;
    report->size += parser->global.report_size * parser->global.report_count;
    /* Total size check: Allow for possible report index byte */
    if (report->size > (HID_MAX_BUFFER_SIZE - 1) << HID_MAX_BUFFER_SIZE_SHIFT_MASK) {
        return -EPERM;
    }
    if (!parser->local.usage_index) { /* Ignore padding fields */
        return 0;
    }
    usages = max_t(unsigned, parser->local.usage_index, parser->global.report_count);
    field = hid_register_field(report, usages);
    if (!field) {
        return 0;
    }
    field->physical = hid_lookup_collection(parser, HID_COLLECTION_PHYSICAL);
    field->logical = hid_lookup_collection(parser, HID_COLLECTION_LOGICAL);
    field->application = application;
    for (i = 0; i < usages; i++) {
        unsigned j = i;
        /* Duplicate the last usage we parsed if we have excess values */
        if (i >= parser->local.usage_index) {
            j = parser->local.usage_index - 1;
        }
        field->usage[i].hid = parser->local.usage[j];
        field->usage[i].collection_index = parser->local.collection_index[j];
        field->usage[i].usage_index = i;
        field->usage[i].resolution_multiplier = 1;
    }
    field->maxusage = usages;
    field->flags = flags;
    field->report_offset = offset;
    field->report_type = report_type;
    field->report_size = parser->global.report_size;
    field->report_count = parser->global.report_count;
    field->logical_minimum = parser->global.logical_minimum;
    field->logical_maximum = parser->global.logical_maximum;
    field->physical_minimum = parser->global.physical_minimum;
    field->physical_maximum = parser->global.physical_maximum;
    field->unit_exponent = parser->global.unit_exponent;
    field->unit = parser->global.unit;
    return 0;
}

/*
 * Read data value from item.
 */
static u32 item_udata(struct hid_item *item)
{
    switch (item->size) {
        case HID_ITEM_UDATA_BYTE:
            return item->data.u8;
        case HID_ITEM_UDATA_WORD:
            return item->data.u16;
        case HID_ITEM_UDATA_DWORD:
            return item->data.u32;
    }
    return 0;
}

static s32 item_sdata(struct hid_item *item)
{
    switch (item->size) {
        case HID_ITEM_SDATA_BYTE:
            return item->data.s8;
        case HID_ITEM_SDATA_WORD:
            return item->data.s16;
        case HID_ITEM_SDATA_DWORD:
            return item->data.s32;
    }
    return 0;
}

/*
 * Process a global item.
 */

static int hid_parser_global(struct hid_parser *parser, struct hid_item *item)
{
    s32 raw_value;
    switch (item->tag) {
        case HID_GLOBAL_ITEM_TAG_PUSH:

            if (parser->global_stack_ptr == HID_GLOBAL_STACK_SIZE) {
                return -EPERM;
            }

            memcpy(parser->global_stack + parser->global_stack_ptr++, &parser->global, sizeof(struct hid_global));
            return 0;

        case HID_GLOBAL_ITEM_TAG_POP:

            if (!parser->global_stack_ptr) {
                return -EPERM;
            }

            memcpy(&parser->global, parser->global_stack + --parser->global_stack_ptr, sizeof(struct hid_global));
            return 0;

        case HID_GLOBAL_ITEM_TAG_USAGE_PAGE:
            parser->global.usage_page = item_udata(item);
            return 0;

        case HID_GLOBAL_ITEM_TAG_LOGICAL_MINIMUM:
            parser->global.logical_minimum = item_sdata(item);
            return 0;

        case HID_GLOBAL_ITEM_TAG_LOGICAL_MAXIMUM:
            if (parser->global.logical_minimum < 0) {
                parser->global.logical_maximum = item_sdata(item);
            } else {
                parser->global.logical_maximum = item_udata(item);
            }
            return 0;

        case HID_GLOBAL_ITEM_TAG_PHYSICAL_MINIMUM:
            parser->global.physical_minimum = item_sdata(item);
            return 0;

        case HID_GLOBAL_ITEM_TAG_PHYSICAL_MAXIMUM:
            if (parser->global.physical_minimum < 0) {
                parser->global.physical_maximum = item_sdata(item);
            } else {
                parser->global.physical_maximum = item_udata(item);
            }
            return 0;

        case HID_GLOBAL_ITEM_TAG_UNIT_EXPONENT:
            /* Many devices provide unit exponent as a two's complement
             * nibble due to the common misunderstanding of HID
             * specification 1.11, 6.2.2.7 Global Items. Attempt to handle
             * both this and the standard encoding. */
            raw_value = item_sdata(item);
            if (!(raw_value & 0xfffffff0)) {
                parser->global.unit_exponent = hid_snto32(raw_value, 0x4);
            } else {
                parser->global.unit_exponent = raw_value;
            }
            return 0;

        case HID_GLOBAL_ITEM_TAG_UNIT:
            parser->global.unit = item_udata(item);
            return 0;

        case HID_GLOBAL_ITEM_TAG_REPORT_SIZE:
            parser->global.report_size = item_udata(item);
            if (parser->global.report_size > HID_REPORT_SIZE) {
                return -EPERM;
            }
            return 0;

        case HID_GLOBAL_ITEM_TAG_REPORT_COUNT:
            parser->global.report_count = item_udata(item);
            if (parser->global.report_count > HID_MAX_USAGES) {
                return -EPERM;
            }
            return 0;

        case HID_GLOBAL_ITEM_TAG_REPORT_ID:
            parser->global.report_id = item_udata(item);
            if (parser->global.report_id == 0 || parser->global.report_id >= HID_MAX_IDS) {
                return -EPERM;
            }
            return 0;

        default:
            return -EPERM;
    }
}

/*
 * Process a local item.
 */

static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
{
    u32 data;
    unsigned n;
    u32 count;

    data = item_udata(item);

    switch (item->tag) {
        case HID_LOCAL_ITEM_TAG_DELIMITER:

            if (data) {
                /*
                 * We treat items before the first delimiter
                 * as global to all usage sets (branch 0).
                 * In the moment we process only these global
                 * items and the first delimiter set.
                 */
                if (parser->local.delimiter_depth != 0) {
                    return -EPERM;
                }
                parser->local.delimiter_depth++;
                parser->local.delimiter_branch++;
            } else {
                if (parser->local.delimiter_depth < 1) {
                    return -EPERM;
                }
                parser->local.delimiter_depth--;
            }
            return 0;

        case HID_LOCAL_ITEM_TAG_USAGE:

            if (parser->local.delimiter_branch > 1) {
                return 0;
            }

            return hid_add_usage(parser, data, item->size);

        case HID_LOCAL_ITEM_TAG_USAGE_MINIMUM:

            if (parser->local.delimiter_branch > 1) {
                return 0;
            }

            parser->local.usage_minimum = data;
            return 0;

        case HID_LOCAL_ITEM_TAG_USAGE_MAXIMUM:

            if (parser->local.delimiter_branch > 1) {
                return 0;
            }

            count = data - parser->local.usage_minimum;
            if (count + parser->local.usage_index >= HID_MAX_USAGES) {
                /*
                 * We do not warn if the name is not set, we are
                 * actually pre-scanning the device.
                 */
                if (dev_name(&parser->device->dev)) {
                    data = HID_MAX_USAGES - parser->local.usage_index + parser->local.usage_minimum - 1;
                }
                if (data <= 0) {
                    return -EPERM;
                }
            }

            for (n = parser->local.usage_minimum; n <= data; n++) {
                if (hid_add_usage(parser, n, item->size)) {
                    return -EPERM;
                }
            }
            return 0;

        default:

            return 0;
    }
    return 0;
}

/*
 * Concatenate Usage Pages into Usages where relevant:
 * As per specification, 6.2.2.8: "When the parser encounters a main item it
 * concatenates the last declared Usage Page with a Usage to form a complete
 * usage value."
 */

static void hid_concatenate_last_usage_page(struct hid_parser *parser)
{
    int i;
    unsigned int usage_page;
    unsigned int current_page;

    if (!parser->local.usage_index) {
        return;
    }

    usage_page = parser->global.usage_page;

    /*
     * Concatenate usage page again only if last declared Usage Page
     * has not been already used in previous usages concatenation
     */
    for (i = parser->local.usage_index - 1; i >= 0; i--) {
        if (parser->local.usage_size[i] > HID_ADD_USAGE_SIZE) {
            /* Ignore extended usages */
            continue;
        }

        current_page = parser->local.usage[i] >> HID_COMPLETE_USAGE_SHIFT_MASK;
        if (current_page == usage_page) {
            break;
        }

        complete_usage(parser, i);
    }
}

/*
 * Process a main item.
 */

static int hid_parser_main(struct hid_parser *parser, struct hid_item *item)
{
    u32 data;
    int ret;

    hid_concatenate_last_usage_page(parser);

    data = item_udata(item);

    switch (item->tag) {
        case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
            ret = open_collection(parser, data & HID_OPEN_COLLECTION_TYPE_MASK);
            break;
        case HID_MAIN_ITEM_TAG_END_COLLECTION:
            ret = close_collection(parser);
            break;
        case HID_MAIN_ITEM_TAG_INPUT:
            ret = hid_add_field(parser, HID_INPUT_REPORT, data);
            break;
        case HID_MAIN_ITEM_TAG_OUTPUT:
            ret = hid_add_field(parser, HID_OUTPUT_REPORT, data);
            break;
        case HID_MAIN_ITEM_TAG_FEATURE:
            ret = hid_add_field(parser, HID_FEATURE_REPORT, data);
            break;
        default:
            ret = 0;
    }

    memset(&parser->local, 0, sizeof(parser->local)); /* Reset the local parser environment */

    return ret;
}

/*
 * Process a reserved item.
 */

static int hid_parser_reserved(struct hid_parser *parser, struct hid_item *item)
{
    return 0;
}

/*
 * Free a report and all registered fields. The field->usage and
 * field->value table's are allocated behind the field, so we need
 * only to free(field) itself.
 */

static void hid_free_report(struct hid_report *report)
{
    unsigned n;

    for (n = 0; n < report->maxfield; n++) {
        kfree(report->field[n]);
    }
    kfree(report);
}

/*
 * Close report. This function returns the device
 * state to the point prior to hid_open_report().
 */
static void hid_close_report(struct hid_device *device)
{
    unsigned i, j;

    for (i = 0; i < HID_REPORT_TYPES; i++) {
        struct hid_report_enum *report_enum = device->report_enum + i;

        for (j = 0; j < HID_MAX_IDS; j++) {
            struct hid_report *report = report_enum->report_id_hash[j];
            if (report) {
                hid_free_report(report);
            }
        }
        memset(report_enum, 0, sizeof(*report_enum));
        INIT_LIST_HEAD(&report_enum->report_list);
    }

    kfree(device->rdesc);
    device->rdesc = NULL;
    device->rsize = 0;

    kfree(device->collection);
    device->collection = NULL;
    device->collection_size = 0;
    device->maxcollection = 0;
    device->maxapplication = 0;

    device->status &= ~HID_STAT_PARSED;
}

/*
 * Free a device structure, all reports, and all fields.
 */

static void hid_device_release(struct device *dev)
{
    struct hid_device *hid = to_hid_device(dev);

    hid_close_report(hid);
    kfree(hid->dev_rdesc);
    kfree(hid);
}

/*
 * Fetch a report description item from the data stream. We support long
 * items, though they are not used yet.
 */

static u8 *fetch_item(u8 *start, u8 *end, struct hid_item *item)
{
    u8 b;
    if ((end - start) <= 0) {
        return NULL;
    }
    b = *start++;
    item->type = (b >> HID_FETCH_ITEM_SHIFT_MASK_TWO) & HID_FETCH_ITEM_SHIFT_BIT_MASK_THREE;
    item->tag = (b >> HID_FETCH_ITEM_SHIFT_MASK_FOUR) & HID_FETCH_ITEM_SHIFT_BIT_MASK_FIFTEEN;
    if (item->tag == HID_ITEM_TAG_LONG) {
        item->format = HID_ITEM_FORMAT_LONG;
        if ((end - start) < HID_FETCH_ITEM_SIZE_WORD) {
            return NULL;
        }
        item->size = *start++;
        item->tag = *start++;
        if ((end - start) < item->size) {
            return NULL;
        }
        item->data.longdata = start;
        start += item->size;
        return start;
    }
    item->format = HID_ITEM_FORMAT_SHORT;
    item->size = b & HID_FETCH_ITEM_SHIFT_BIT_MASK_THREE;

    switch (item->size) {
        case HID_FETCH_ITEM_SIZE_ZERO:
            return start;
        case HID_FETCH_ITEM_SIZE_ONE:
            if ((end - start) < HID_FETCH_ITEM_SIZE_ONE) {
                return NULL;
            }
            item->data.u8 = *start++;
            return start;
        case HID_FETCH_ITEM_SIZE_TWO:
            if ((end - start) < HID_FETCH_ITEM_SIZE_TWO) {
                return NULL;
            }
            item->data.u16 = get_unaligned_le16(start);
            start = (u8 *)((u16 *)start + 1);
            return start;
        case HID_FETCH_ITEM_SIZE_THREE:
            item->size++;
            if ((end - start) < HID_FETCH_ITEM_SIZE_FOUR) {
                return NULL;
            }
            item->data.u32 = get_unaligned_le32(start);
            start = (u8 *)((u32 *)start + 1);
            return start;
    }
    return NULL;
}

static void hid_scan_input_usage(struct hid_parser *parser, u32 usage)
{
    struct hid_device *hid = parser->device;

    if (usage == HID_DG_CONTACTID) {
        hid->group = HID_GROUP_MULTITOUCH;
    }
}

static void hid_scan_feature_usage(struct hid_parser *parser, u32 usage)
{
    if (usage == HID_SCAN_FEATURE_USAGE_REG_C5 && parser->global.report_count == HID_REPORT_SIZE &&
        parser->global.report_size == HID_GLOBAL_REPORT_SIZE) {
        parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
    }

    if (usage == HID_SCAN_FEATURE_USAGE_REG_C6 && parser->global.report_count == HID_REPORT_COUNT_SIZE_ONE &&
        parser->global.report_size == HID_GLOBAL_REPORT_SIZE) {
        parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
    }
}

static void hid_scan_collection(struct hid_parser *parser, unsigned type)
{
    struct hid_device *hid = parser->device;
    int i;

    if (((parser->global.usage_page << HID_GLOBAL_USAGE_PAGE_SHIFT_MASK) == HID_UP_SENSOR) &&
        type == HID_COLLECTION_PHYSICAL) {
        hid->group = HID_GROUP_SENSOR_HUB;
    }

    if (hid->vendor == USB_VENDOR_ID_MICROSOFT && hid->product == USB_DEVICE_ID_MS_POWER_COVER &&
        hid->group == HID_GROUP_MULTITOUCH) {
        hid->group = HID_GROUP_GENERIC;
    }

    if ((parser->global.usage_page << HID_GLOBAL_USAGE_PAGE_SHIFT_MASK) == HID_UP_GENDESK) {
        for (i = 0; i < parser->local.usage_index; i++) {
            if (parser->local.usage[i] == HID_GD_POINTER) {
                parser->scan_flags |= HID_SCAN_FLAG_GD_POINTER;
            }
        }
    }

    if ((parser->global.usage_page << HID_GLOBAL_USAGE_PAGE_SHIFT_MASK) >= HID_UP_MSVENDOR) {
        parser->scan_flags |= HID_SCAN_FLAG_VENDOR_SPECIFIC;
    }

    if ((parser->global.usage_page << HID_GLOBAL_USAGE_PAGE_SHIFT_MASK) == HID_UP_GOOGLEVENDOR) {
        for (i = 0; i < parser->local.usage_index; i++) {
            if (parser->local.usage[i] == (HID_UP_GOOGLEVENDOR | HID_UP_VENDOR_MASK)) {
                parser->device->group = HID_GROUP_VIVALDI;
            }
        }
    }
}

static int hid_scan_main(struct hid_parser *parser, struct hid_item *item)
{
    u32 data;
    int i;

    hid_concatenate_last_usage_page(parser);

    data = item_udata(item);

    switch (item->tag) {
        case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
            hid_scan_collection(parser, data & HID_COLLECTION_TYPE_MASK);
            break;
        case HID_MAIN_ITEM_TAG_END_COLLECTION:
            break;
        case HID_MAIN_ITEM_TAG_INPUT:
            /* ignore constant inputs, they will be ignored by hid-input */
            if (data & HID_MAIN_ITEM_CONSTANT) {
                break;
            }
            for (i = 0; i < parser->local.usage_index; i++) {
                hid_scan_input_usage(parser, parser->local.usage[i]);
            }
            break;
        case HID_MAIN_ITEM_TAG_OUTPUT:
            break;
        case HID_MAIN_ITEM_TAG_FEATURE:
            for (i = 0; i < parser->local.usage_index; i++) {
                hid_scan_feature_usage(parser, parser->local.usage[i]);
            }
            break;
    }

    /* Reset the local parser environment */
    memset(&parser->local, 0, sizeof(parser->local));

    return 0;
}

/*
 * Scan a report descriptor before the device is added to the bus.
 * Sets device groups and other properties that determine what driver
 * to load.
 */
static int hid_scan_report(struct hid_device *hid)
{
    struct hid_parser *parser;
    struct hid_item item;
    u8 *start = hid->dev_rdesc;
    u8 *end = start + hid->dev_rsize;
    static int (*dispatch_type[])(struct hid_parser * parser, struct hid_item * item) = {
        hid_scan_main, hid_parser_global, hid_parser_local, hid_parser_reserved};

    parser = vzalloc(sizeof(struct hid_parser));
    if (!parser) {
        return -ENOMEM;
    }

    parser->device = hid;
    hid->group = HID_GROUP_GENERIC;

    /*
     * The parsing is simpler than the one in hid_open_report() as we should
     * be robust against hid errors. Those errors will be raised by
     * hid_open_report() anyway.
     */
    while ((start = fetch_item(start, end, &item)) != NULL) {
        dispatch_type[item.type](parser, &item);
    }

    /*
     * Handle special flags set during scanning.
     */
    if ((parser->scan_flags & HID_SCAN_FLAG_MT_WIN_8) && (hid->group == HID_GROUP_MULTITOUCH)) {
        hid->group = HID_GROUP_MULTITOUCH_WIN_8;
    }

    /*
     * Vendor specific handlings
     */
    switch (hid->vendor) {
        case USB_VENDOR_ID_WACOM:
            hid->group = HID_GROUP_WACOM;
            break;
        case USB_VENDOR_ID_SYNAPTICS:
            if (hid->group == HID_GROUP_GENERIC) {
                if ((parser->scan_flags & HID_SCAN_FLAG_VENDOR_SPECIFIC) &&
                    (parser->scan_flags & HID_SCAN_FLAG_GD_POINTER)) {
                    /*
                     * hid-rmi should take care of them,
                     * not hid-generic
                     */
                    hid->group = HID_GROUP_RMI;
                }
            }
            break;
    }

    kfree(parser->collection_stack);
    vfree(parser);
    return 0;
}

/**
 * hid_parse_report - parse device report
 *
 * @hid: hid device
 * @start: report start
 * @size: report size
 *
 * Allocate the device report as read by the bus driver. This function should
 * only be called from parse() in ll drivers.
 */
int hid_parse_report(struct hid_device *hid, u8 *start, unsigned size)
{
    hid->dev_rdesc = kmemdup(start, size, GFP_KERNEL);
    if (!hid->dev_rdesc) {
        return -ENOMEM;
    }
    hid->dev_rsize = size;
    return 0;
}
EXPORT_SYMBOL_GPL(hid_parse_report);

static const char *const hid_report_names[] = {
    "HID_INPUT_REPORT",
    "HID_OUTPUT_REPORT",
    "HID_FEATURE_REPORT",
};
/**
 * hid_validate_values - validate existing device report's value indexes
 *
 * @hid: hid device
 * @type: which report type to examine
 * @id: which report ID to examine (0 for first)
 * @field_index: which report field to examine
 * @report_counts: expected number of values
 *
 * Validate the number of values in a given field of a given report, after
 * parsing.
 */
struct hid_report *hid_validate_values(struct hid_device *hid, unsigned int type, unsigned int id,
                                       unsigned int field_index, unsigned int report_counts)
{
    struct hid_report *report;

    if (type > HID_FEATURE_REPORT) {
        return NULL;
    }

    if (id >= HID_MAX_IDS) {
        return NULL;
    }

    /*
     * Explicitly not using hid_get_report() here since it depends on
     * ->numbered being checked, which may not always be the case when
     * drivers go to access report values.
     */
    if (id == 0) {
        /*
         * Validating on id 0 means we should examine the first
         * report in the list.
         */
        report = list_entry(hid->report_enum[type].report_list.next, struct hid_report, list);
    } else {
        report = hid->report_enum[type].report_id_hash[id];
    }
    if (!report) {
        return NULL;
    }
    if (report->maxfield <= field_index) {
        return NULL;
    }
    if (report->field[field_index]->report_count < report_counts) {
        return NULL;
    }
    return report;
}
EXPORT_SYMBOL_GPL(hid_validate_values);

static int hid_calculate_multiplier(struct hid_device *hid, struct hid_field *multiplier)
{
    int m;
    s32 v = *multiplier->value;
    s32 lmin = multiplier->logical_minimum;
    s32 lmax = multiplier->logical_maximum;
    s32 pmin = multiplier->physical_minimum;
    s32 pmax = multiplier->physical_maximum;

    /*
     * "Because OS implementations will generally divide the control's
     * reported count by the Effective Resolution Multiplier, designers
     * should take care not to establish a potential Effective
     * Resolution Multiplier of zero."
     * HID Usage Table, v1.12, Section 4.3.1, p31
     */
    if (lmax - lmin == 0) {
        return 1;
    }
    /*
     * Handling the unit exponent is left as an exercise to whoever
     * finds a device where that exponent is not 0.
     */
    m = ((v - lmin) / (lmax - lmin) * (pmax - pmin) + pmin);

    /* There are no devices with an effective multiplier > 255 */
    if (unlikely(m == 0 || m > HID_MULTIPLIER_MAX || m < -HID_MULTIPLIER_MAX)) {
        m = 1;
    }

    return m;
}

static void hid_apply_multiplier_to_field(struct hid_device *hid, struct hid_field *field,
                                          struct hid_collection *multiplier_collection, int effective_multiplier)
{
    struct hid_collection *collection;
    struct hid_usage *usage;
    int i;

    /*
     * If multiplier_collection is NULL, the multiplier applies
     * to all fields in the report.
     * Otherwise, it is the Logical Collection the multiplier applies to
     * but our field may be in a subcollection of that collection.
     */
    for (i = 0; i < field->maxusage; i++) {
        usage = &field->usage[i];

        collection = &hid->collection[usage->collection_index];
        while (collection->parent_idx != -1 && collection != multiplier_collection) {
            collection = &hid->collection[collection->parent_idx];
        }

        if (collection->parent_idx != -1 || multiplier_collection == NULL) {
            usage->resolution_multiplier = effective_multiplier;
        }
    }
}

static void hid_apply_multiplier(struct hid_device *hid, struct hid_field *multiplier)
{
    struct hid_report_enum *rep_enum;
    struct hid_report *rep;
    struct hid_field *field;
    struct hid_collection *multiplier_collection;
    int effective_multiplier;
    int i;

    /*
     * "The Resolution Multiplier control must be contained in the same
     * Logical Collection as the control(s) to which it is to be applied.
     * If no Resolution Multiplier is defined, then the Resolution
     * Multiplier defaults to 1.  If more than one control exists in a
     * Logical Collection, the Resolution Multiplier is associated with
     * all controls in the collection. If no Logical Collection is
     * defined, the Resolution Multiplier is associated with all
     * controls in the report."
     * HID Usage Table, v1.12, Section 4.3.1, p30
     *
     * Thus, search from the current collection upwards until we find a
     * logical collection. Then search all fields for that same parent
     * collection. Those are the fields the multiplier applies to.
     *
     * If we have more than one multiplier, it will overwrite the
     * applicable fields later.
     */
    multiplier_collection = &hid->collection[multiplier->usage->collection_index];
    while (multiplier_collection->parent_idx != -1 && multiplier_collection->type != HID_COLLECTION_LOGICAL) {
        multiplier_collection = &hid->collection[multiplier_collection->parent_idx];
    }

    effective_multiplier = hid_calculate_multiplier(hid, multiplier);

    rep_enum = &hid->report_enum[HID_INPUT_REPORT];
    list_for_each_entry(rep, &rep_enum->report_list, list)
    {
        for (i = 0; i < rep->maxfield; i++) {
            field = rep->field[i];
            hid_apply_multiplier_to_field(hid, field, multiplier_collection, effective_multiplier);
        }
    }
}

/*
 * hid_setup_resolution_multiplier - set up all resolution multipliers
 *
 * @device: hid device
 *
 * Search for all Resolution Multiplier Feature Reports and apply their
 * value to all matching Input items. This only updates the internal struct
 * fields.
 *
 * The Resolution Multiplier is applied by the hardware. If the multiplier
 * is anything other than 1, the hardware will send pre-multiplied events
 * so that the same physical interaction generates an accumulated
 *    accumulated_value = value * * multiplier
 * This may be achieved by sending
 * - "value * multiplier" for each event, or
 * - "value" but "multiplier" times as frequently, or
 * - a combination of the above
 * The only guarantee is that the same physical interaction always generates
 * an accumulated 'value * multiplier'.
 *
 * This function must be called before any event processing and after
 * any SetRequest to the Resolution Multiplier.
 */
void hid_setup_resolution_multiplier(struct hid_device *hid)
{
    struct hid_report_enum *rep_enum;
    struct hid_report *rep;
    struct hid_usage *usage;
    int i, j;

    rep_enum = &hid->report_enum[HID_FEATURE_REPORT];
    list_for_each_entry(rep, &rep_enum->report_list, list)
    {
        for (i = 0; i < rep->maxfield; i++) {
            /* Ignore if report count is out of bounds. */
            if (rep->field[i]->report_count < 1) {
                continue;
            }

            for (j = 0; j < rep->field[i]->maxusage; j++) {
                usage = &rep->field[i]->usage[j];
                if (usage->hid == HID_GD_RESOLUTION_MULTIPLIER) {
                    hid_apply_multiplier(hid, rep->field[i]);
                }
            }
        }
    }
}
EXPORT_SYMBOL_GPL(hid_setup_resolution_multiplier);

/**
 * hid_open_report - open a driver-specific device report
 *
 * @device: hid device
 *
 * Parse a report description into a hid_device structure. Reports are
 * enumerated, fields are attached to these reports.
 * 0 returned on success, otherwise nonzero error value.
 *
 * This function (or the equivalent hid_parse() macro) should only be
 * called from probe() in drivers, before starting the device.
 */
int hid_open_report(struct hid_device *device)
{
    struct hid_parser *parser;
    struct hid_item item;
    unsigned int size;
    u8 *start;
    u8 *buf;
    u8 *end;
    u8 *next;
    int ret;
    static int (*dispatch_type[])(struct hid_parser * parser, struct hid_item * item) = {
        hid_parser_main, hid_parser_global, hid_parser_local, hid_parser_reserved};

    if (WARN_ON(device->status & HID_STAT_PARSED)) {
        return -EBUSY;
    }

    start = device->dev_rdesc;
    if (WARN_ON(!start)) {
        return -ENODEV;
    }
    size = device->dev_rsize;

    buf = kmemdup(start, size, GFP_KERNEL);
    if (buf == NULL) {
        return -ENOMEM;
    }

    if (device->driver->report_fixup) {
        start = device->driver->report_fixup(device, buf, &size);
    } else {
        start = buf;
    }

    start = kmemdup(start, size, GFP_KERNEL);
    kfree(buf);
    if (start == NULL) {
        return -ENOMEM;
    }

    device->rdesc = start;
    device->rsize = size;

    parser = vzalloc(sizeof(struct hid_parser));
    if (!parser) {
        ret = -ENOMEM;
        goto alloc_err;
    }

    parser->device = device;

    end = start + size;

    device->collection = kcalloc(HID_DEFAULT_NUM_COLLECTIONS, sizeof(struct hid_collection), GFP_KERNEL);
    if (!device->collection) {
        ret = -ENOMEM;
        goto err;
    }
    device->collection_size = HID_DEFAULT_NUM_COLLECTIONS;

    ret = -EINVAL;
    while ((next = fetch_item(start, end, &item)) != NULL) {
        start = next;

        if (item.format != HID_ITEM_FORMAT_SHORT) {
            goto err;
        }

        if (dispatch_type[item.type](parser, &item)) {
            goto err;
        }

        if (start == end) {
            if (parser->collection_stack_ptr) {
                goto err;
            }
            if (parser->local.delimiter_depth) {
                goto err;
            }

            /*
             * fetch initial values in case the device's
             * default multiplier isn't the recommended 1
             */
            hid_setup_resolution_multiplier(device);

            kfree(parser->collection_stack);
            vfree(parser);
            device->status |= HID_STAT_PARSED;

            return 0;
        }
    }

err:
    kfree(parser->collection_stack);
alloc_err:
    vfree(parser);
    hid_close_report(device);
    return ret;
}
EXPORT_SYMBOL_GPL(hid_open_report);

/*
 * Convert a signed n-bit integer to signed 32-bit integer. Common
 * cases are done through the compiler, the screwed things has to be
 * done by hand.
 */

static s32 snto32(u32 value, unsigned n)
{
    if (!value || !n) {
        return 0;
    }

    switch (n) {
        case HID_BYTE_BIT_WIDTH:
            return ((s8)value);
        case HID_WORD_BIT_WIDTH:
            return ((s16)value);
        case HID_DWORD_BIT_WIDTH:
            return ((s32)value);
        default:
            break;
    }
    return value & (1 << (n - 1)) ? value | (~0U << n) : value;
}

s32 hid_snto32(u32 value, unsigned n)
{
    return snto32(value, n);
}
EXPORT_SYMBOL_GPL(hid_snto32);

/*
 * Convert a signed 32-bit integer to a signed n-bit integer.
 */

static u32 s32ton(s32 value, unsigned n)
{
    s32 a = value >> (n - 1);
    if (a && a != -1) {
        return value < 0 ? 1 << (n - 1) : (1 << (n - 1)) - 1;
    }
    return value & ((1 << n) - 1);
}

/*
 * Extract/implement a data field from/to a little endian report (bit array).
 *
 * Code sort-of follows HID spec:
 *     http://www.usb.org/developers/hidpage/HID1_11.pdf
 *
 * While the USB HID spec allows unlimited length bit fields in "report
 * descriptors", most devices never use more than 16 bits.
 * One model of UPS is claimed to report "LINEV" as a 32-bit field.
 * Search linux-kernel and linux-usb-devel archives for "hid-core extract".
 */

static u32 hid_core_extract(u8 *report, unsigned offset, int n)
{
    unsigned int idx = offset / 8;
    unsigned int bit_nr = 0;
    unsigned int bit_shift = offset % 8;
    int bits_to_copy = 8 - bit_shift;
    u32 value = 0;
    u32 mask = n < HID_DWORD_BIT_WIDTH ? (1U << n) - 1 : ~0U;

    while (n > 0) {
        value |= ((u32)report[idx] >> bit_shift) << bit_nr;
        n -= bits_to_copy;
        bit_nr += bits_to_copy;
        bits_to_copy = HID_BYTE_BIT_WIDTH;
        bit_shift = 0;
        idx++;
    }

    return value & mask;
}

u32 hid_field_extract(const struct hid_device *hid, u8 *report, unsigned offset, unsigned n)
{
    if (n > HID_DWORD_BIT_WIDTH) {
        n = HID_DWORD_BIT_WIDTH;
    }

    return hid_core_extract(report, offset, n);
}
EXPORT_SYMBOL_GPL(hid_field_extract);

/*
 * "implement" : set bits in a little endian bit stream.
 * Same concepts as "extract" (see comments above).
 * The data mangled in the bit stream remains in little endian
 * order the whole time. It make more sense to talk about
 * endianness of register values by considering a register
 * a "cached" copy of the little endian bit stream.
 */

static void hid_core_implement(u8 *report, unsigned offset, int n, u32 value)
{
    unsigned int idx = offset / HID_BYTE_BIT_WIDTH;
    unsigned int bit_shift = offset % HID_BYTE_BIT_WIDTH;
    int bits_to_set = HID_BYTE_BIT_WIDTH - bit_shift;

    while (n - bits_to_set >= 0) {
        report[idx] &= ~(HID_BYTE_BIT_MASK << bit_shift);
        report[idx] |= value << bit_shift;
        value >>= bits_to_set;
        n -= bits_to_set;
        bits_to_set = HID_BYTE_BIT_WIDTH;
        bit_shift = 0;
        idx++;
    }

    /* last nibble */
    if (n) {
        u8 bit_mask = ((1U << n) - 1);
        report[idx] &= ~(bit_mask << bit_shift);
        report[idx] |= value << bit_shift;
    }
}

static void implement(const struct hid_device *hid, u8 *report, unsigned offset, unsigned n, u32 value)
{
    if (unlikely(n > HID_DWORD_BIT_WIDTH)) {
        n = HID_DWORD_BIT_WIDTH;
    } else if (n < HID_DWORD_BIT_WIDTH) {
        u32 m = (1U << n) - 1;

        if (unlikely(value > m)) {
            WARN_ON(1);
            value &= m;
        }
    }

    hid_core_implement(report, offset, n, value);
}

/*
 * Search an array for a value.
 */

static int search(s32 *array, s32 value, unsigned n)
{
    while (n--) {
        if (*array++ == value) {
            return 0;
        }
    }
    return -EPERM;
}

/**
 * hid_match_report - check if driver's raw_event should be called
 *
 * @hid: hid device
 * @report: hid report to match against
 *
 * compare hid->driver->report_table->report_type to report->type
 */
static int hid_match_report(struct hid_device *hid, struct hid_report *report)
{
    const struct hid_report_id *id = hid->driver->report_table;

    if (!id) { /* NULL means all */
        return 1;
    }

    for (; id->report_type != HID_TERMINATOR; id++) {
        if (id->report_type == HID_ANY_ID || id->report_type == report->type) {
            return 1;
        }
    }
    return 0;
}

/**
 * hid_match_usage - check if driver's event should be called
 *
 * @hid: hid device
 * @usage: usage to match against
 *
 * compare hid->driver->usage_table->usage_{type,code} to
 * usage->usage_{type,code}
 */
static int hid_match_usage(struct hid_device *hid, struct hid_usage *usage)
{
    const struct hid_usage_id *id = hid->driver->usage_table;

    if (!id) { /* NULL means all */
        return 1;
    }

    for (; id->usage_type != HID_ANY_ID - 1; id++) {
        if ((id->usage_hid == HID_ANY_ID || id->usage_hid == usage->hid) &&
            (id->usage_type == HID_ANY_ID || id->usage_type == usage->type) &&
            (id->usage_code == HID_ANY_ID || id->usage_code == usage->code)) {
            return 1;
        }
    }
    return 0;
}

static void hid_process_event(struct hid_device *hid, struct hid_field *field, struct hid_usage *usage, s32 value,
                              int interrupt)
{
    struct hid_driver *hdrv = hid->driver;
    int ret;

    if (!list_empty(&hid->debug_list)) {
        hid_dump_input(hid, usage, value);
    }

    if (hdrv && hdrv->event && hid_match_usage(hid, usage)) {
        ret = hdrv->event(hid, field, usage, value);
        if (ret != 0) {
            if (ret < 0) {
                return;
            }
        }
    }

    if (hid->claimed & HID_CLAIMED_INPUT) {
        hidinput_hid_event(hid, field, usage, value);
    }
    if ((hid->claimed & HID_CLAIMED_HIDDEV) && interrupt && hid->hiddev_hid_event) {
        hid->hiddev_hid_event(hid, field, usage, value);
    }
}

/*
 * Analyse a received field, and fetch the data from it. The field
 * content is stored for next report processing (we do differential
 * reporting to the layer).
 */

static void hid_input_field(struct hid_device *hid, struct hid_field *field, u8 *data, int interrupt)
{
    unsigned n;
    unsigned count = field->report_count;
    unsigned offset = field->report_offset;
    unsigned size = field->report_size;
    s32 min = field->logical_minimum;
    s32 max = field->logical_maximum;
    s32 *value;

    value = kmalloc_array(count, sizeof(s32), GFP_ATOMIC);
    if (!value) {
        return;
    }
    for (n = 0; n < count; n++) {
        value[n] = min < 0 ? snto32(hid_field_extract(hid, data, offset + n * size, size), size)
                           : hid_field_extract(hid, data, offset + n * size, size);

        /* Ignore report if ErrorRollOver */
        if (!(field->flags & HID_MAIN_ITEM_VARIABLE) && value[n] >= min && value[n] <= max &&
            value[n] - min < field->maxusage && field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1) {
            goto exit;
        }
    }

    for (n = 0; n < count; n++) {
        if (HID_MAIN_ITEM_VARIABLE & field->flags) {
            hid_process_event(hid, field, &field->usage[n], value[n], interrupt);
            continue;
        }
        if (field->value[n] >= min && field->value[n] <= max && field->value[n] - min < field->maxusage &&
            field->usage[field->value[n] - min].hid && search(value, field->value[n], count)) {
            hid_process_event(hid, field, &field->usage[field->value[n] - min], 0, interrupt);
        }
        if (value[n] >= min && value[n] <= max && value[n] - min < field->maxusage &&
            field->usage[value[n] - min].hid && search(field->value, value[n], count)) {
            hid_process_event(hid, field, &field->usage[value[n] - min], 1, interrupt);
        }
    }
    memcpy(field->value, value, count * sizeof(s32));
exit:
    kfree(value);
}

/*
 * Output the field into the report.
 */

static void hid_output_field(const struct hid_device *hid, struct hid_field *field, u8 *data)
{
    unsigned count = field->report_count;
    unsigned offset = field->report_offset;
    unsigned size = field->report_size;
    unsigned n;

    for (n = 0; n < count; n++) {
        if (field->logical_minimum < 0) { /* signed values */
            implement(hid, data, offset + n * size, size, s32ton(field->value[n], size));
        } else { /* unsigned values */
            implement(hid, data, offset + n * size, size, field->value[n]);
        }
    }
}

/*
 * Compute the size of a report.
 */
static size_t hid_compute_report_size(struct hid_report *report)
{
    if (report->size) {
        return ((report->size - 1) >> HID_REPORT_SIEZE_MASK) + 1;
    }

    return 0;
}

/*
 * Create a report. 'data' has to be allocated using
 * hid_alloc_report_buf() so that it has proper size.
 */

void hid_output_report(struct hid_report *report, u8 *data)
{
    unsigned n;

    if (report->id > 0) {
        *data++ = report->id;
    }

    memset(data, 0, hid_compute_report_size(report));
    for (n = 0; n < report->maxfield; n++) {
        hid_output_field(report->device, report->field[n], data);
    }
}
EXPORT_SYMBOL_GPL(hid_output_report);

/*
 * Allocator for buffer that is going to be passed to hid_output_report()
 */
u8 *hid_alloc_report_buf(struct hid_report *report, gfp_t flags)
{
    /*
     * 7 extra bytes are necessary to achieve proper functionality
     * of implement() working on 8 byte chunks
     */

    u32 len = hid_report_len(report) + HID_BYTE_CHUNK;

    return kmalloc(len, flags);
}
EXPORT_SYMBOL_GPL(hid_alloc_report_buf);

/*
 * Set a field value. The report this field belongs to has to be
 * created and transferred to the device, to set this value in the
 * device.
 */

int hid_set_field(struct hid_field *field, unsigned offset, s32 value)
{
    unsigned size;

    if (!field) {
        return -EPERM;
    }

    size = field->report_size;

    hid_dump_input(field->report->device, field->usage + offset, value);

    if (offset >= field->report_count) {
        return -EPERM;
    }
    if (field->logical_minimum < 0) {
        if (value != snto32(s32ton(value, size), size)) {
            return -EPERM;
        }
    }
    field->value[offset] = value;
    return 0;
}
EXPORT_SYMBOL_GPL(hid_set_field);

static struct hid_report *hid_get_report(struct hid_report_enum *report_enum, const u8 *data)
{
    struct hid_report *report;
    unsigned int n = 0; /* Normally report number is 0 */

    /* Device uses numbered reports, data[0] is report number */
    if (report_enum->numbered) {
        n = *data;
    }

    report = report_enum->report_id_hash[n];

    return report;
}

/*
 * Implement a generic .request() callback, using .raw_request()
 * DO NOT USE in hid drivers directly, but through hid_hw_request instead.
 */
int __hid_request(struct hid_device *hid, struct hid_report *report, int reqtype)
{
    char *buf;
    int ret;
    u32 len;

    buf = hid_alloc_report_buf(report, GFP_KERNEL);
    if (!buf) {
        return -ENOMEM;
    }

    len = hid_report_len(report);

    if (reqtype == HID_REQ_SET_REPORT) {
        hid_output_report(report, buf);
    }

    ret = hid->ll_driver->raw_request(hid, report->id, buf, len, report->type, reqtype);
    if (ret < 0) {
        goto out;
    }

    if (reqtype == HID_REQ_GET_REPORT) {
        hid_input_report(hid, report->type, buf, ret, 0);
    }

    ret = 0;

out:
    kfree(buf);
    return ret;
}
EXPORT_SYMBOL_GPL(__hid_request);

int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, u32 size, int interrupt)
{
    struct hid_report_enum *report_enum = hid->report_enum + type;
    struct hid_report *report;
    struct hid_driver *hdrv;
    unsigned int a;
    u32 rsize, csize = size;
    u8 *cdata = data;
    int ret = 0;

    report = hid_get_report(report_enum, data);
    if (!report) {
        goto out;
    }

    if (report_enum->numbered) {
        cdata++;
        csize--;
    }

    rsize = hid_compute_report_size(report);
    if (report_enum->numbered && rsize >= HID_MAX_BUFFER_SIZE) {
        rsize = HID_MAX_BUFFER_SIZE - 1;
    } else if (rsize > HID_MAX_BUFFER_SIZE) {
        rsize = HID_MAX_BUFFER_SIZE;
    }

    if (csize < rsize) {
        memset(cdata + csize, 0, rsize - csize);
    }

    if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_report_event) {
        hid->hiddev_report_event(hid, report);
    }
    if (hid->claimed & HID_CLAIMED_HIDRAW) {
        ret = hidraw_report_event(hid, data, size);
        if (ret) {
            goto out;
        }
    }

    if (hid->claimed != HID_CLAIMED_HIDRAW && report->maxfield) {
        for (a = 0; a < report->maxfield; a++) {
            hid_input_field(hid, report->field[a], cdata, interrupt);
        }
        hdrv = hid->driver;
        if (hdrv && hdrv->report) {
            hdrv->report(hid, report);
        }
    }

    if (hid->claimed & HID_CLAIMED_INPUT) {
        hidinput_report_event(hid, report);
    }
out:
    return ret;
}
EXPORT_SYMBOL_GPL(hid_report_raw_event);

/**
 * hid_input_report - report data from lower layer (usb, bt...)
 *
 * @hid: hid device
 * @type: HID report type (HID_*_REPORT)
 * @data: report contents
 * @size: size of data parameter
 * @interrupt: distinguish between interrupt and control transfers
 *
 * This is data entry for lower layers.
 */
int hid_input_report(struct hid_device *hid, int type, u8 *data, u32 size, int interrupt)
{
    struct hid_report_enum *report_enum;
    struct hid_driver *hdrv;
    struct hid_report *report;
    int ret = 0;
    if (!hid) {
        return -ENODEV;
    }
    if (down_trylock(&hid->driver_input_lock)) {
        return -EBUSY;
    }
    if (!hid->driver) {
        ret = -ENODEV;
        goto unlock;
    }
    report_enum = hid->report_enum + type;
    hdrv = hid->driver;
    if (!size) {
        ret = -1;
        goto unlock;
    }
    /* Avoid unnecessary overhead if debugfs is disabled */
    if (!list_empty(&hid->debug_list)) {
        hid_dump_report(hid, type, data, size);
    }
    report = hid_get_report(report_enum, data);
    if (!report) {
        ret = -1;
        goto unlock;
    }
    if (hdrv && hdrv->raw_event && hid_match_report(hid, report)) {
        ret = hdrv->raw_event(hid, report, data, size);
        if (ret < 0) {
            goto unlock;
        }
    }
    ret = hid_report_raw_event(hid, type, data, size, interrupt);
unlock:
    up(&hid->driver_input_lock);
    return ret;
}
EXPORT_SYMBOL_GPL(hid_input_report);

bool hid_match_one_id(const struct hid_device *hdev, const struct hid_device_id *id)
{
    return (id->bus == HID_BUS_ANY || id->bus == hdev->bus) &&
           (id->group == HID_GROUP_ANY || id->group == hdev->group) &&
           (id->vendor == HID_ANY_ID || id->vendor == hdev->vendor) &&
           (id->product == HID_ANY_ID || id->product == hdev->product);
}

const struct hid_device_id *hid_match_id(const struct hid_device *hdev, const struct hid_device_id *id)
{
    for (; id->bus; id++) {
        if (hid_match_one_id(hdev, id)) {
            return id;
        }
    }

    return NULL;
}

static const struct hid_device_id hid_hiddev_list[] = {{HID_USB_DEVICE(USB_VENDOR_ID_MGE, USB_DEVICE_ID_MGE_UPS)},
                                                       {HID_USB_DEVICE(USB_VENDOR_ID_MGE, USB_DEVICE_ID_MGE_UPS1)},
                                                       {}};

static bool hid_hiddev(struct hid_device *hdev)
{
    return !!hid_match_id(hdev, hid_hiddev_list);
}

static ssize_t read_report_descriptor(struct file *filp, struct kobject *kobj, struct bin_attribute *attr, char *buf,
                                      loff_t off, size_t count)
{
    struct device *dev = kobj_to_dev(kobj);
    struct hid_device *hdev = to_hid_device(dev);

    if (off >= hdev->rsize) {
        return 0;
    }

    if (off + count > hdev->rsize) {
        count = hdev->rsize - off;
    }

    memcpy(buf, hdev->rdesc + off, count);

    return count;
}

static ssize_t show_country(struct device *dev, struct device_attribute *attr, char *buf)
{
    struct hid_device *hdev = to_hid_device(dev);

    return sprintf(buf, "%02x\n", hdev->country & 0xff);
}

static struct bin_attribute dev_bin_attr_report_desc = {
    .attr = {.name = "report_descriptor", .mode = 0444},
    .read = read_report_descriptor,
    .size = HID_MAX_DESCRIPTOR_SIZE,
};

static const struct device_attribute dev_attr_country = {
    .attr = {.name = "country", .mode = 0444},
    .show = show_country,
};

int hid_connect(struct hid_device *hdev, unsigned int connect_mask)
{
    static const char *types[] = {
        "Device", "Pointer", "Mouse", "Device", "Joystick", "Gamepad", "Keyboard", "Keypad", "Multi-Axis Controller"};
    const char *type, *bus;
    char buf[64] = "";
    unsigned int i;
    int len;
    int ret;

    if (hdev->quirks & HID_QUIRK_HIDDEV_FORCE) {
        connect_mask |= (HID_CONNECT_HIDDEV_FORCE | HID_CONNECT_HIDDEV);
    }
    if (hdev->quirks & HID_QUIRK_HIDINPUT_FORCE) {
        connect_mask |= HID_CONNECT_HIDINPUT_FORCE;
    }
    if (hdev->bus != BUS_USB) {
        connect_mask &= ~HID_CONNECT_HIDDEV;
    }
    if (hid_hiddev(hdev)) {
        connect_mask |= HID_CONNECT_HIDDEV_FORCE;
    }

    if ((connect_mask & HID_CONNECT_HIDINPUT) && !hidinput_connect(hdev, connect_mask & HID_CONNECT_HIDINPUT_FORCE)) {
        hdev->claimed |= HID_CLAIMED_INPUT;
    }

    if ((connect_mask & HID_CONNECT_HIDDEV) && hdev->hiddev_connect &&
        !hdev->hiddev_connect(hdev, connect_mask & HID_CONNECT_HIDDEV_FORCE)) {
        hdev->claimed |= HID_CLAIMED_HIDDEV;
    }
    if ((connect_mask & HID_CONNECT_HIDRAW) && !hidraw_connect(hdev)) {
        hdev->claimed |= HID_CLAIMED_HIDRAW;
    }

    if (connect_mask & HID_CONNECT_DRIVER) {
        hdev->claimed |= HID_CLAIMED_DRIVER;
    }

    /* Drivers with the ->raw_event callback set are not required to connect
     * to any other listener. */
    if (!hdev->claimed && !hdev->driver->raw_event) {
        return -ENODEV;
    }

    if ((hdev->claimed & HID_CLAIMED_INPUT) && (connect_mask & HID_CONNECT_FF) && hdev->ff_init) {
        hdev->ff_init(hdev);
    }

    len = 0;
    if (hdev->claimed & HID_CLAIMED_INPUT) {
        len += sprintf(buf + len, "input");
    }
    if (hdev->claimed & HID_CLAIMED_HIDDEV) {
        len += sprintf(buf + len, "%shiddev%d", len ? "," : "", ((struct hiddev *)hdev->hiddev)->minor);
    }
    if (hdev->claimed & HID_CLAIMED_HIDRAW) {
        len += sprintf(buf + len, "%shidraw%d", len ? "," : "", ((struct hidraw *)hdev->hidraw)->minor);
    }

    type = "Device";
    for (i = 0; i < hdev->maxcollection; i++) {
        struct hid_collection *col = &hdev->collection[i];
        if (col->type == HID_COLLECTION_APPLICATION && (col->usage & HID_USAGE_PAGE) == HID_UP_GENDESK &&
            (col->usage & 0xffff) < ARRAY_SIZE(types)) {
            type = types[col->usage & 0xffff];
            break;
        }
    }

    switch (hdev->bus) {
        case BUS_USB:
            bus = "USB";
            break;
        case BUS_BLUETOOTH:
            bus = "BLUETOOTH";
            break;
        case BUS_I2C:
            bus = "I2C";
            break;
        case BUS_VIRTUAL:
            bus = "VIRTUAL";
            break;
        default:
            bus = "<UNKNOWN>";
    }

    ret = device_create_file(&hdev->dev, &dev_attr_country);
    return 0;
}
EXPORT_SYMBOL_GPL(hid_connect);

void hid_disconnect(struct hid_device *hdev)
{
    device_remove_file(&hdev->dev, &dev_attr_country);
    if (hdev->claimed & HID_CLAIMED_INPUT) {
        hidinput_disconnect(hdev);
    }
    if (hdev->claimed & HID_CLAIMED_HIDDEV) {
        hdev->hiddev_disconnect(hdev);
    }
    if (hdev->claimed & HID_CLAIMED_HIDRAW) {
        hidraw_disconnect(hdev);
    }
    hdev->claimed = 0;
}
EXPORT_SYMBOL_GPL(hid_disconnect);

/**
 * hid_hw_start - start underlying HW
 * @hdev: hid device
 * @connect_mask: which outputs to connect, see HID_CONNECT_*
 *
 * Call this in probe function *after* hid_parse. This will setup HW
 * buffers and start the device (if not defeirred to device open).
 * hid_hw_stop must be called if this was successful.
 */
int hid_hw_start(struct hid_device *hdev, unsigned int connect_mask)
{
    int error;

    error = hdev->ll_driver->start(hdev);
    if (error) {
        return error;
    }

    if (connect_mask) {
        error = hid_connect(hdev, connect_mask);
        if (error) {
            hdev->ll_driver->stop(hdev);
            return error;
        }
    }

    return 0;
}
EXPORT_SYMBOL_GPL(hid_hw_start);

/**
 * hid_hw_stop - stop underlying HW
 * @hdev: hid device
 *
 * This is usually called from remove function or from probe when something
 * failed and hid_hw_start was called already.
 */
void hid_hw_stop(struct hid_device *hdev)
{
    hid_disconnect(hdev);
    hdev->ll_driver->stop(hdev);
}
EXPORT_SYMBOL_GPL(hid_hw_stop);

/**
 * hid_hw_open - signal underlying HW to start delivering events
 * @hdev: hid device
 *
 * Tell underlying HW to start delivering events from the device.
 * This function should be called sometime after successful call
 * to hid_hw_start().
 */
int hid_hw_open(struct hid_device *hdev)
{
    int ret;

    ret = mutex_lock_killable(&hdev->ll_open_lock);
    if (ret) {
        return ret;
    }

    if (!hdev->ll_open_count++) {
        ret = hdev->ll_driver->open(hdev);
        if (ret) {
            hdev->ll_open_count--;
        }
    }

    mutex_unlock(&hdev->ll_open_lock);
    return ret;
}
EXPORT_SYMBOL_GPL(hid_hw_open);

/**
 * hid_hw_close - signal underlaying HW to stop delivering events
 *
 * @hdev: hid device
 *
 * This function indicates that we are not interested in the events
 * from this device anymore. Delivery of events may or may not stop,
 * depending on the number of users still outstanding.
 */
void hid_hw_close(struct hid_device *hdev)
{
    mutex_lock(&hdev->ll_open_lock);
    if (!--hdev->ll_open_count) {
        hdev->ll_driver->close(hdev);
    }
    mutex_unlock(&hdev->ll_open_lock);
}
EXPORT_SYMBOL_GPL(hid_hw_close);

struct hid_dynid {
    struct list_head list;
    struct hid_device_id id;
};

/**
 * store_new_id - add a new HID device ID to this driver and re-probe devices
 * @drv: target device driver
 * @buf: buffer for scanning device ID data
 * @count: input size
 *
 * Adds a new dynamic hid device ID to this driver,
 * and causes the driver to probe for all devices again.
 */
static ssize_t new_id_store(struct device_driver *drv, const char *buf, size_t count)
{
    struct hid_driver *hdrv = to_hid_driver(drv);
    struct hid_dynid *dynid;
    u32 bus, vendor, product;
    unsigned long driver_data = 0;
    int ret;

    ret = sscanf(buf, "%x %x %x %lx", &bus, &vendor, &product, &driver_data);
    if (ret < 0x3) {
        return -EINVAL;
    }

    dynid = kzalloc(sizeof(*dynid), GFP_KERNEL);
    if (!dynid) {
        return -ENOMEM;
    }

    dynid->id.bus = bus;
    dynid->id.group = HID_GROUP_ANY;
    dynid->id.vendor = vendor;
    dynid->id.product = product;
    dynid->id.driver_data = driver_data;

    spin_lock(&hdrv->dyn_lock);
    list_add_tail(&dynid->list, &hdrv->dyn_list);
    spin_unlock(&hdrv->dyn_lock);

    ret = driver_attach(&hdrv->driver);

    return ret ?: count;
}
static DRIVER_ATTR_WO(new_id);

static struct attribute *hid_drv_attrs[] = {
    &driver_attr_new_id.attr,
    NULL,
};
ATTRIBUTE_GROUPS(hid_drv);

static void hid_free_dynids(struct hid_driver *hdrv)
{
    struct hid_dynid *dynid, *n;

    spin_lock(&hdrv->dyn_lock);
    list_for_each_entry_safe(dynid, n, &hdrv->dyn_list, list)
    {
        list_del(&dynid->list);
        kfree(dynid);
    }
    spin_unlock(&hdrv->dyn_lock);
}

const struct hid_device_id *hid_match_device(struct hid_device *hdev, struct hid_driver *hdrv)
{
    struct hid_dynid *dynid;

    spin_lock(&hdrv->dyn_lock);
    list_for_each_entry(dynid, &hdrv->dyn_list, list)
    {
        if (hid_match_one_id(hdev, &dynid->id)) {
            spin_unlock(&hdrv->dyn_lock);
            return &dynid->id;
        }
    }
    spin_unlock(&hdrv->dyn_lock);

    return hid_match_id(hdev, hdrv->id_table);
}
EXPORT_SYMBOL_GPL(hid_match_device);

static int hid_bus_match(struct device *dev, struct device_driver *drv)
{
    struct hid_driver *hdrv = to_hid_driver(drv);
    struct hid_device *hdev = to_hid_device(dev);

    return hid_match_device(hdev, hdrv) != NULL;
}

/**
 * hid_compare_device_paths - check if both devices share the same path
 * @hdev_a: hid device
 * @hdev_b: hid device
 * @separator: char to use as separator
 *
 * Check if two devices share the same path up to the last occurrence of
 * the separator char. Both paths must exist (i.e., zero-length paths
 * don't match).
 */
bool hid_compare_device_paths(struct hid_device *hdev_a, struct hid_device *hdev_b, char separator)
{
    int n1 = strrchr(hdev_a->phys, separator) - hdev_a->phys;
    int n2 = strrchr(hdev_b->phys, separator) - hdev_b->phys;
    if (n1 != n2 || n1 <= 0 || n2 <= 0) {
        return false;
    }
    return !strncmp(hdev_a->phys, hdev_b->phys, n1);
}
EXPORT_SYMBOL_GPL(hid_compare_device_paths);

static int hid_device_probe(struct device *dev)
{
    struct hid_driver *hdrv = to_hid_driver(dev->driver);
    struct hid_device *hdev = to_hid_device(dev);
    const struct hid_device_id *id;
    int ret = 0;

    if (down_interruptible(&hdev->driver_input_lock)) {
        ret = -EINTR;
        goto end;
    }
    hdev->io_started = false;

    clear_bit(ffs(HID_STAT_REPROBED), &hdev->status);

    if (!hdev->driver) {
        id = hid_match_device(hdev, hdrv);
        if (id == NULL) {
            ret = -ENODEV;
            goto unlock;
        }

        if (hdrv->match) {
            if (!hdrv->match(hdev, hid_ignore_special_drivers)) {
                ret = -ENODEV;
                goto unlock;
            }
        } else {
            /*
             * hid-generic implements .match(), so if
             * hid_ignore_special_drivers is set, we can safely
             * return.
             */
            if (hid_ignore_special_drivers) {
                ret = -ENODEV;
                goto unlock;
            }
        }

        /* reset the quirks that has been previously set */
        hdev->quirks = hid_lookup_quirk(hdev);
        hdev->driver = hdrv;
        if (hdrv->probe) {
            ret = hdrv->probe(hdev, id);
        } else { /* default probe */
            ret = hid_open_report(hdev);
            if (!ret) {
                ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
            }
        }
        if (ret) {
            hid_close_report(hdev);
            hdev->driver = NULL;
        }
    }
unlock:
    if (!hdev->io_started) {
        up(&hdev->driver_input_lock);
    }
end:
    return ret;
}

static int hid_device_remove(struct device *dev)
{
    struct hid_device *hdev = to_hid_device(dev);
    struct hid_driver *hdrv;

    down(&hdev->driver_input_lock);
    hdev->io_started = false;

    hdrv = hdev->driver;
    if (hdrv) {
        if (hdrv->remove) {
            hdrv->remove(hdev);
        } else { /* default remove */
            hid_hw_stop(hdev);
        }
        hid_close_report(hdev);
        hdev->driver = NULL;
    }

    if (!hdev->io_started) {
        up(&hdev->driver_input_lock);
    }

    return 0;
}

static ssize_t modalias_show(struct device *dev, struct device_attribute *a, char *buf)
{
    struct hid_device *hdev = container_of(dev, struct hid_device, dev);

    return scnprintf(buf, PAGE_SIZE, "hid:b%04Xg%04Xv%08Xp%08X\n", hdev->bus, hdev->group, hdev->vendor, hdev->product);
}
static DEVICE_ATTR_RO(modalias);

static struct attribute *hid_dev_attrs[] = {
    &dev_attr_modalias.attr,
    NULL,
};
static struct bin_attribute *hid_dev_bin_attrs[] = {&dev_bin_attr_report_desc, NULL};
static const struct attribute_group hid_dev_group = {
    .attrs = hid_dev_attrs,
    .bin_attrs = hid_dev_bin_attrs,
};
__ATTRIBUTE_GROUPS(hid_dev);

static int hid_uevent(struct device *dev, struct kobj_uevent_env *env)
{
    struct hid_device *hdev = to_hid_device(dev);

    if (add_uevent_var(env, "HID_ID=%04X:%08X:%08X", hdev->bus, hdev->vendor, hdev->product)) {
        return -ENOMEM;
    }

    if (add_uevent_var(env, "HID_NAME=%s", hdev->name)) {
        return -ENOMEM;
    }

    if (add_uevent_var(env, "HID_PHYS=%s", hdev->phys)) {
        return -ENOMEM;
    }

    if (add_uevent_var(env, "HID_UNIQ=%s", hdev->uniq)) {
        return -ENOMEM;
    }

    if (add_uevent_var(env, "MODALIAS=hid:b%04Xg%04Xv%08Xp%08X", hdev->bus, hdev->group, hdev->vendor, hdev->product)) {
        return -ENOMEM;
    }

    return 0;
}

struct bus_type hid_bus_type = {
    .name = "hid",
    .dev_groups = hid_dev_groups,
    .drv_groups = hid_drv_groups,
    .match = hid_bus_match,
    .probe = hid_device_probe,
    .remove = hid_device_remove,
    .uevent = hid_uevent,
};
EXPORT_SYMBOL(hid_bus_type);

int hid_add_device(struct hid_device *hdev)
{
    static atomic_t id = ATOMIC_INIT(0);
    int ret;

    if (WARN_ON(hdev->status & HID_STAT_ADDED)) {
        return -EBUSY;
    }

    hdev->quirks = hid_lookup_quirk(hdev);

    /* we need to kill them here, otherwise they will stay allocated to
     * wait for coming driver */
    if (hid_ignore(hdev)) {
        return -ENODEV;
    }

    /*
     * Check for the mandatory transport channel.
     */
    if (!hdev->ll_driver->raw_request) {
        return -EINVAL;
    }

    /*
     * Read the device report descriptor once and use as template
     * for the driver-specific modifications.
     */
    ret = hdev->ll_driver->parse(hdev);
    if (ret) {
        return ret;
    }
    if (!hdev->dev_rdesc) {
        return -ENODEV;
    }

    /*
     * Scan generic devices for group information
     */
    if (hid_ignore_special_drivers) {
        hdev->group = HID_GROUP_GENERIC;
    } else if (!hdev->group && !(hdev->quirks & HID_QUIRK_HAVE_SPECIAL_DRIVER)) {
        ret = hid_scan_report(hdev);
    }

    /* XXX hack, any other cleaner solution after the driver core
     * is converted to allow more than 20 bytes as the device name? */
    dev_set_name(&hdev->dev, "%04X:%04X:%04X.%04X", hdev->bus, hdev->vendor, hdev->product, atomic_inc_return(&id));

    hid_debug_register(hdev, dev_name(&hdev->dev));
    ret = device_add(&hdev->dev);
    if (!ret) {
        hdev->status |= HID_STAT_ADDED;
    } else {
        hid_debug_unregister(hdev);
    }

    return ret;
}
EXPORT_SYMBOL_GPL(hid_add_device);

/**
 * hid_allocate_device - allocate new hid device descriptor
 *
 * Allocate and initialize hid device, so that hid_destroy_device might be
 * used to free it.
 *
 * New hid_device pointer is returned on success, otherwise ERR_PTR encoded
 * error value.
 */
struct hid_device *hid_allocate_device(void)
{
    struct hid_device *hdev;
    int ret = -ENOMEM;

    hdev = kzalloc(sizeof(*hdev), GFP_KERNEL);
    if (hdev == NULL) {
        return ERR_PTR(ret);
    }

    device_initialize(&hdev->dev);
    hdev->dev.release = hid_device_release;
    hdev->dev.bus = &hid_bus_type;
    device_enable_async_suspend(&hdev->dev);

    hid_close_report(hdev);

    init_waitqueue_head(&hdev->debug_wait);
    INIT_LIST_HEAD(&hdev->debug_list);
    spin_lock_init(&hdev->debug_list_lock);
    sema_init(&hdev->driver_input_lock, 1);
    mutex_init(&hdev->ll_open_lock);

    return hdev;
}
EXPORT_SYMBOL_GPL(hid_allocate_device);

static void hid_remove_device(struct hid_device *hdev)
{
    if (hdev->status & HID_STAT_ADDED) {
        device_del(&hdev->dev);
        hid_debug_unregister(hdev);
        hdev->status &= ~HID_STAT_ADDED;
    }
    kfree(hdev->dev_rdesc);
    hdev->dev_rdesc = NULL;
    hdev->dev_rsize = 0;
}

/**
 * hid_destroy_device - free previously allocated device
 *
 * @hdev: hid device
 *
 * If you allocate hid_device through hid_allocate_device, you should ever
 * free by this function.
 */
void hid_destroy_device(struct hid_device *hdev)
{
    hid_remove_device(hdev);
    put_device(&hdev->dev);
}
EXPORT_SYMBOL_GPL(hid_destroy_device);

static int hid_bus_reprobe_drivers(struct device *dev, void *data)
{
    struct hid_driver *hdrv = data;
    struct hid_device *hdev = to_hid_device(dev);

    if (hdev->driver == hdrv && !hdrv->match(hdev, hid_ignore_special_drivers) &&
        !test_and_set_bit(ffs(HID_STAT_REPROBED), &hdev->status)) {
        return device_reprobe(dev);
    }

    return 0;
}

static int hid_bus_driver_added(struct device_driver *drv, void *data)
{
    struct hid_driver *hdrv = to_hid_driver(drv);

    if (hdrv->match) {
        bus_for_each_dev(&hid_bus_type, NULL, hdrv, hid_bus_reprobe_drivers);
    }

    return 0;
}

static int bus_removed_driver(struct device_driver *drv, void *data)
{
    return bus_rescan_devices(&hid_bus_type);
}

int __hid_register_driver(struct hid_driver *hdrv, struct module *owner, const char *mod_name)
{
    int ret;
    hdrv->driver.name = hdrv->name;
    hdrv->driver.bus = &hid_bus_type;
    hdrv->driver.owner = owner;
    hdrv->driver.mod_name = mod_name;
    INIT_LIST_HEAD(&hdrv->dyn_list);
    spin_lock_init(&hdrv->dyn_lock);
    ret = driver_register(&hdrv->driver);
    if (ret == 0) {
        bus_for_each_drv(&hid_bus_type, NULL, NULL, hid_bus_driver_added);
    }
    return ret;
}
EXPORT_SYMBOL_GPL(__hid_register_driver);

void hid_unregister_driver(struct hid_driver *hdrv)
{
    driver_unregister(&hdrv->driver);
    hid_free_dynids(hdrv);

    bus_for_each_drv(&hid_bus_type, NULL, hdrv, bus_removed_driver);
}
EXPORT_SYMBOL_GPL(hid_unregister_driver);

int hid_check_keys_pressed(struct hid_device *hid)
{
    struct hid_input *hidinput;
    int i;

    if (!(hid->claimed & HID_CLAIMED_INPUT)) {
        return 0;
    }

    list_for_each_entry(hidinput, &hid->inputs, list)
    {
        for (i = 0; i < BITS_TO_LONGS(KEY_MAX); i++) {
            if (hidinput->input->key[i]) {
                return 1;
            }
        }
    }

    return 0;
}

EXPORT_SYMBOL_GPL(hid_check_keys_pressed);

static int __init hid_init(void)
{
    int ret;

    if (hid_debug) {
        pr_warn("hid_debug is now used solely for parser and driver debugging.\n"
                "debugfs is now used for inspecting the device (report descriptor, reports)\n");
    }

    ret = bus_register(&hid_bus_type);
    if (ret) {
        pr_err("can't register hid bus\n");
        goto err;
    }

    ret = hidraw_init();
    if (ret) {
        goto err_bus;
    }

    hid_debug_init();

    return 0;
err_bus:
    bus_unregister(&hid_bus_type);
err:
    return ret;
}

static void __exit hid_exit(void)
{
    hid_debug_exit();
    hidraw_exit();
    bus_unregister(&hid_bus_type);
    hid_quirks_exit(HID_BUS_ANY);
}

module_init(hid_init);
module_exit(hid_exit);

MODULE_AUTHOR("Andreas Gal");
MODULE_AUTHOR("Vojtech Pavlik");
MODULE_AUTHOR("Jiri Kosina");
MODULE_LICENSE("GPL");