hid-multitouch.c

Go to the documentation of this file.

/*
 *  HID driver for multitouch panels
 *
 *  Copyright (c) 2010-2012 Stephane Chatty <[email protected]>
 *  Copyright (c) 2010-2012 Benjamin Tissoires <[email protected]>
 *  Copyright (c) 2010-2012 Ecole Nationale de l'Aviation Civile, France
 *
 *  This code is partly based on hid-egalax.c:
 *
 *  Copyright (c) 2010 Stephane Chatty <[email protected]>
 *  Copyright (c) 2010 Henrik Rydberg <[email protected]>
 *  Copyright (c) 2010 Canonical, Ltd.
 *
 *  This code is partly based on hid-3m-pct.c:
 *
 *  Copyright (c) 2009-2010 Stephane Chatty <[email protected]>
 *  Copyright (c) 2010      Henrik Rydberg <[email protected]>
 *  Copyright (c) 2010      Canonical, Ltd.
 *
 */

/*
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 */

#include <linux/device.h>
#include <linux/hid.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/input/mt.h>
#include "usbhid/usbhid.h"


MODULE_AUTHOR("Stephane Chatty <[email protected]>");
MODULE_AUTHOR("Benjamin Tissoires <[email protected]>");
MODULE_DESCRIPTION("HID multitouch panels");
MODULE_LICENSE("GPL");

#include "hid-ids.h"

/* quirks to control the device */
#define MT_QUIRK_NOT_SEEN_MEANS_UP  (1 << 0)
#define MT_QUIRK_SLOT_IS_CONTACTID  (1 << 1)
#define MT_QUIRK_CYPRESS        (1 << 2)
#define MT_QUIRK_SLOT_IS_CONTACTNUMBER  (1 << 3)
#define MT_QUIRK_ALWAYS_VALID       (1 << 4)
#define MT_QUIRK_VALID_IS_INRANGE   (1 << 5)
#define MT_QUIRK_VALID_IS_CONFIDENCE    (1 << 6)
#define MT_QUIRK_SLOT_IS_CONTACTID_MINUS_ONE    (1 << 8)
#define MT_QUIRK_NO_AREA        (1 << 9)

struct mt_slot {
    __s32 x, y, p, w, h;
    __s32 contactid;    /* the device ContactID assigned to this slot */
    bool touch_state;   /* is the touch valid? */
};

struct mt_class {
    __s32 name; /* MT_CLS */
    __s32 quirks;
    __s32 sn_move;  /* Signal/noise ratio for move events */
    __s32 sn_width; /* Signal/noise ratio for width events */
    __s32 sn_height;    /* Signal/noise ratio for height events */
    __s32 sn_pressure;  /* Signal/noise ratio for pressure events */
    __u8 maxcontacts;
    bool is_indirect;   /* true for touchpads */
};

struct mt_fields {
    unsigned usages[HID_MAX_FIELDS];
    unsigned int length;
};

struct mt_device {
    struct mt_slot curdata; /* placeholder of incoming data */
    struct mt_class mtclass;    /* our mt device class */
    struct mt_fields *fields;   /* temporary placeholder for storing the
                       multitouch fields */
    unsigned last_field_index;  /* last field index of the report */
    unsigned last_slot_field;   /* the last field of a slot */
    __s8 inputmode;     /* InputMode HID feature, -1 if non-existent */
    __s8 inputmode_index;   /* InputMode HID feature index in the report */
    __s8 maxcontact_report_id;  /* Maximum Contact Number HID feature,
                   -1 if non-existent */
    __u8 num_received;  /* how many contacts we received */
    __u8 num_expected;  /* expected last contact index */
    __u8 maxcontacts;
    __u8 touches_by_report; /* how many touches are present in one report:
                * 1 means we should use a serial protocol
                * > 1 means hybrid (multitouch) protocol */
    bool serial_maybe;  /* need to check for serial protocol */
    bool curvalid;      /* is the current contact valid? */
    unsigned mt_flags;  /* flags to pass to input-mt */
};

/* classes of device behavior */
#define MT_CLS_DEFAULT              0x0001

#define MT_CLS_SERIAL               0x0002
#define MT_CLS_CONFIDENCE           0x0003
#define MT_CLS_CONFIDENCE_CONTACT_ID        0x0004
#define MT_CLS_CONFIDENCE_MINUS_ONE     0x0005
#define MT_CLS_DUAL_INRANGE_CONTACTID       0x0006
#define MT_CLS_DUAL_INRANGE_CONTACTNUMBER   0x0007
#define MT_CLS_DUAL_NSMU_CONTACTID      0x0008
#define MT_CLS_INRANGE_CONTACTNUMBER        0x0009

/* vendor specific classes */
#define MT_CLS_3M               0x0101
#define MT_CLS_CYPRESS              0x0102
#define MT_CLS_EGALAX               0x0103
#define MT_CLS_EGALAX_SERIAL            0x0104
#define MT_CLS_TOPSEED              0x0105
#define MT_CLS_PANASONIC            0x0106
#define MT_CLS_FLATFROG             0x0107
#define MT_CLS_GENERALTOUCH_TWOFINGERS      0x0108
#define MT_CLS_GENERALTOUCH_PWT_TENFINGERS  0x0109

#define MT_DEFAULT_MAXCONTACT   10

#define MT_USB_DEVICE(v, p) HID_DEVICE(BUS_USB, HID_GROUP_MULTITOUCH, v, p)
#define MT_BT_DEVICE(v, p)  HID_DEVICE(BUS_BLUETOOTH, HID_GROUP_MULTITOUCH, v, p)

/*
 * these device-dependent functions determine what slot corresponds
 * to a valid contact that was just read.
 */

static int cypress_compute_slot(struct mt_device *td)
{
    if (td->curdata.contactid != 0 || td->num_received == 0)
        return td->curdata.contactid;
    else
        return -1;
}

static struct mt_class mt_classes[] = {
    { .name = MT_CLS_DEFAULT,
        .quirks = MT_QUIRK_NOT_SEEN_MEANS_UP },
    { .name = MT_CLS_SERIAL,
        .quirks = MT_QUIRK_ALWAYS_VALID},
    { .name = MT_CLS_CONFIDENCE,
        .quirks = MT_QUIRK_VALID_IS_CONFIDENCE },
    { .name = MT_CLS_CONFIDENCE_CONTACT_ID,
        .quirks = MT_QUIRK_VALID_IS_CONFIDENCE |
            MT_QUIRK_SLOT_IS_CONTACTID },
    { .name = MT_CLS_CONFIDENCE_MINUS_ONE,
        .quirks = MT_QUIRK_VALID_IS_CONFIDENCE |
            MT_QUIRK_SLOT_IS_CONTACTID_MINUS_ONE },
    { .name = MT_CLS_DUAL_INRANGE_CONTACTID,
        .quirks = MT_QUIRK_VALID_IS_INRANGE |
            MT_QUIRK_SLOT_IS_CONTACTID,
        .maxcontacts = 2 },
    { .name = MT_CLS_DUAL_INRANGE_CONTACTNUMBER,
        .quirks = MT_QUIRK_VALID_IS_INRANGE |
            MT_QUIRK_SLOT_IS_CONTACTNUMBER,
        .maxcontacts = 2 },
    { .name = MT_CLS_DUAL_NSMU_CONTACTID,
        .quirks = MT_QUIRK_NOT_SEEN_MEANS_UP |
            MT_QUIRK_SLOT_IS_CONTACTID,
        .maxcontacts = 2 },
    { .name = MT_CLS_INRANGE_CONTACTNUMBER,
        .quirks = MT_QUIRK_VALID_IS_INRANGE |
            MT_QUIRK_SLOT_IS_CONTACTNUMBER },

    /*
     * vendor specific classes
     */
    { .name = MT_CLS_3M,
        .quirks = MT_QUIRK_VALID_IS_CONFIDENCE |
            MT_QUIRK_SLOT_IS_CONTACTID,
        .sn_move = 2048,
        .sn_width = 128,
        .sn_height = 128,
        .maxcontacts = 60,
    },
    { .name = MT_CLS_CYPRESS,
        .quirks = MT_QUIRK_NOT_SEEN_MEANS_UP |
            MT_QUIRK_CYPRESS,
        .maxcontacts = 10 },
    { .name = MT_CLS_EGALAX,
        .quirks =  MT_QUIRK_SLOT_IS_CONTACTID |
            MT_QUIRK_VALID_IS_INRANGE,
        .sn_move = 4096,
        .sn_pressure = 32,
    },
    { .name = MT_CLS_EGALAX_SERIAL,
        .quirks =  MT_QUIRK_SLOT_IS_CONTACTID |
            MT_QUIRK_ALWAYS_VALID,
        .sn_move = 4096,
        .sn_pressure = 32,
    },
    { .name = MT_CLS_TOPSEED,
        .quirks = MT_QUIRK_ALWAYS_VALID,
        .is_indirect = true,
        .maxcontacts = 2,
    },
    { .name = MT_CLS_PANASONIC,
        .quirks = MT_QUIRK_NOT_SEEN_MEANS_UP,
        .maxcontacts = 4 },
    { .name = MT_CLS_GENERALTOUCH_TWOFINGERS,
        .quirks = MT_QUIRK_NOT_SEEN_MEANS_UP |
            MT_QUIRK_VALID_IS_INRANGE |
            MT_QUIRK_SLOT_IS_CONTACTNUMBER,
        .maxcontacts = 2
    },
    { .name = MT_CLS_GENERALTOUCH_PWT_TENFINGERS,
        .quirks = MT_QUIRK_NOT_SEEN_MEANS_UP |
            MT_QUIRK_SLOT_IS_CONTACTNUMBER
    },

    { .name = MT_CLS_FLATFROG,
        .quirks = MT_QUIRK_NOT_SEEN_MEANS_UP |
            MT_QUIRK_NO_AREA,
        .sn_move = 2048,
        .maxcontacts = 40,
    },
    { }
};

static ssize_t mt_show_quirks(struct device *dev,
               struct device_attribute *attr,
               char *buf)
{
    struct hid_device *hdev = container_of(dev, struct hid_device, dev);
    struct mt_device *td = hid_get_drvdata(hdev);

    return sprintf(buf, "%u\n", td->mtclass.quirks);
}

static ssize_t mt_set_quirks(struct device *dev,
              struct device_attribute *attr,
              const char *buf, size_t count)
{
    struct hid_device *hdev = container_of(dev, struct hid_device, dev);
    struct mt_device *td = hid_get_drvdata(hdev);

    unsigned long val;

    if (kstrtoul(buf, 0, &val))
        return -EINVAL;

    td->mtclass.quirks = val;

    return count;
}

static DEVICE_ATTR(quirks, S_IWUSR | S_IRUGO, mt_show_quirks, mt_set_quirks);

static struct attribute *sysfs_attrs[] = {
    &dev_attr_quirks.attr,
    NULL
};

static struct attribute_group mt_attribute_group = {
    .attrs = sysfs_attrs
};

static void mt_feature_mapping(struct hid_device *hdev,
        struct hid_field *field, struct hid_usage *usage)
{
    struct mt_device *td = hid_get_drvdata(hdev);
    int i;

    switch (usage->hid) {
    case HID_DG_INPUTMODE:
        td->inputmode = field->report->id;
        td->inputmode_index = 0; /* has to be updated below */

        for (i=0; i < field->maxusage; i++) {
            if (field->usage[i].hid == usage->hid) {
                td->inputmode_index = i;
                break;
            }
        }

        break;
    case HID_DG_CONTACTMAX:
        td->maxcontact_report_id = field->report->id;
        td->maxcontacts = field->value[0];
        if (td->mtclass.maxcontacts)
            /* check if the maxcontacts is given by the class */
            td->maxcontacts = td->mtclass.maxcontacts;

        break;
    }
}

static void set_abs(struct input_dev *input, unsigned int code,
        struct hid_field *field, int snratio)
{
    int fmin = field->logical_minimum;
    int fmax = field->logical_maximum;
    int fuzz = snratio ? (fmax - fmin) / snratio : 0;
    input_set_abs_params(input, code, fmin, fmax, fuzz, 0);
}

static void mt_store_field(struct hid_usage *usage, struct mt_device *td,
        struct hid_input *hi)
{
    struct mt_fields *f = td->fields;

    if (f->length >= HID_MAX_FIELDS)
        return;

    f->usages[f->length++] = usage->hid;
}

static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
        struct hid_field *field, struct hid_usage *usage,
        unsigned long **bit, int *max)
{
    struct mt_device *td = hid_get_drvdata(hdev);
    struct mt_class *cls = &td->mtclass;
    int code;

    /* Only map fields from TouchScreen or TouchPad collections.
    * We need to ignore fields that belong to other collections
    * such as Mouse that might have the same GenericDesktop usages. */
    if (field->application == HID_DG_TOUCHSCREEN)
        td->mt_flags |= INPUT_MT_DIRECT;
    else if (field->application != HID_DG_TOUCHPAD)
        return 0;

    /*
     * Model touchscreens providing buttons as touchpads.
     */
    if (field->application == HID_DG_TOUCHPAD ||
        (usage->hid & HID_USAGE_PAGE) == HID_UP_BUTTON)
        td->mt_flags |= INPUT_MT_POINTER;

    /* eGalax devices provide a Digitizer.Stylus input which overrides
     * the correct Digitizers.Finger X/Y ranges.
     * Let's just ignore this input. */
    if (field->physical == HID_DG_STYLUS)
        return -1;

    switch (usage->hid & HID_USAGE_PAGE) {

    case HID_UP_GENDESK:
        switch (usage->hid) {
        case HID_GD_X:
            hid_map_usage(hi, usage, bit, max,
                    EV_ABS, ABS_MT_POSITION_X);
            set_abs(hi->input, ABS_MT_POSITION_X, field,
                cls->sn_move);
            mt_store_field(usage, td, hi);
            td->last_field_index = field->index;
            return 1;
        case HID_GD_Y:
            hid_map_usage(hi, usage, bit, max,
                    EV_ABS, ABS_MT_POSITION_Y);
            set_abs(hi->input, ABS_MT_POSITION_Y, field,
                cls->sn_move);
            mt_store_field(usage, td, hi);
            td->last_field_index = field->index;
            return 1;
        }
        return 0;

    case HID_UP_DIGITIZER:
        switch (usage->hid) {
        case HID_DG_INRANGE:
            mt_store_field(usage, td, hi);
            td->last_field_index = field->index;
            return 1;
        case HID_DG_CONFIDENCE:
            mt_store_field(usage, td, hi);
            td->last_field_index = field->index;
            return 1;
        case HID_DG_TIPSWITCH:
            hid_map_usage(hi, usage, bit, max, EV_KEY, BTN_TOUCH);
            input_set_capability(hi->input, EV_KEY, BTN_TOUCH);
            mt_store_field(usage, td, hi);
            td->last_field_index = field->index;
            return 1;
        case HID_DG_CONTACTID:
            mt_store_field(usage, td, hi);
            td->last_field_index = field->index;
            td->touches_by_report++;
            return 1;
        case HID_DG_WIDTH:
            hid_map_usage(hi, usage, bit, max,
                    EV_ABS, ABS_MT_TOUCH_MAJOR);
            if (!(cls->quirks & MT_QUIRK_NO_AREA))
                set_abs(hi->input, ABS_MT_TOUCH_MAJOR, field,
                    cls->sn_width);
            mt_store_field(usage, td, hi);
            td->last_field_index = field->index;
            return 1;
        case HID_DG_HEIGHT:
            hid_map_usage(hi, usage, bit, max,
                    EV_ABS, ABS_MT_TOUCH_MINOR);
            if (!(cls->quirks & MT_QUIRK_NO_AREA)) {
                set_abs(hi->input, ABS_MT_TOUCH_MINOR, field,
                    cls->sn_height);
                input_set_abs_params(hi->input,
                    ABS_MT_ORIENTATION, 0, 1, 0, 0);
            }
            mt_store_field(usage, td, hi);
            td->last_field_index = field->index;
            return 1;
        case HID_DG_TIPPRESSURE:
            hid_map_usage(hi, usage, bit, max,
                    EV_ABS, ABS_MT_PRESSURE);
            set_abs(hi->input, ABS_MT_PRESSURE, field,
                cls->sn_pressure);
            mt_store_field(usage, td, hi);
            td->last_field_index = field->index;
            return 1;
        case HID_DG_CONTACTCOUNT:
            td->last_field_index = field->index;
            return 1;
        case HID_DG_CONTACTMAX:
            /* we don't set td->last_slot_field as contactcount and
             * contact max are global to the report */
            td->last_field_index = field->index;
            return -1;
        case HID_DG_TOUCH:
            /* Legacy devices use TIPSWITCH and not TOUCH.
             * Let's just ignore this field. */
            return -1;
        }
        /* let hid-input decide for the others */
        return 0;

    case HID_UP_BUTTON:
        code = BTN_MOUSE + ((usage->hid - 1) & HID_USAGE);
        hid_map_usage(hi, usage, bit, max, EV_KEY, code);
        input_set_capability(hi->input, EV_KEY, code);
        return 1;

    case 0xff000000:
        /* we do not want to map these: no input-oriented meaning */
        return -1;
    }

    return 0;
}

static int mt_input_mapped(struct hid_device *hdev, struct hid_input *hi,
        struct hid_field *field, struct hid_usage *usage,
        unsigned long **bit, int *max)
{
    if (usage->type == EV_KEY || usage->type == EV_ABS)
        set_bit(usage->type, hi->input->evbit);

    return -1;
}

static int mt_compute_slot(struct mt_device *td, struct input_dev *input)
{
    __s32 quirks = td->mtclass.quirks;

    if (quirks & MT_QUIRK_SLOT_IS_CONTACTID)
        return td->curdata.contactid;

    if (quirks & MT_QUIRK_CYPRESS)
        return cypress_compute_slot(td);

    if (quirks & MT_QUIRK_SLOT_IS_CONTACTNUMBER)
        return td->num_received;

    if (quirks & MT_QUIRK_SLOT_IS_CONTACTID_MINUS_ONE)
        return td->curdata.contactid - 1;

    return input_mt_get_slot_by_key(input, td->curdata.contactid);
}

/*
 * this function is called when a whole contact has been processed,
 * so that it can assign it to a slot and store the data there
 */
static void mt_complete_slot(struct mt_device *td, struct input_dev *input)
{
    if (td->curvalid) {
        int slotnum = mt_compute_slot(td, input);
        struct mt_slot *s = &td->curdata;

        if (slotnum < 0 || slotnum >= td->maxcontacts)
            return;

        input_mt_slot(input, slotnum);
        input_mt_report_slot_state(input, MT_TOOL_FINGER,
            s->touch_state);
        if (s->touch_state) {
            /* this finger is on the screen */
            int wide = (s->w > s->h);
            /* divided by two to match visual scale of touch */
            int major = max(s->w, s->h) >> 1;
            int minor = min(s->w, s->h) >> 1;

            input_event(input, EV_ABS, ABS_MT_POSITION_X, s->x);
            input_event(input, EV_ABS, ABS_MT_POSITION_Y, s->y);
            input_event(input, EV_ABS, ABS_MT_ORIENTATION, wide);
            input_event(input, EV_ABS, ABS_MT_PRESSURE, s->p);
            input_event(input, EV_ABS, ABS_MT_TOUCH_MAJOR, major);
            input_event(input, EV_ABS, ABS_MT_TOUCH_MINOR, minor);
        }
    }

    td->num_received++;
}

/*
 * this function is called when a whole packet has been received and processed,
 * so that it can decide what to send to the input layer.
 */
static void mt_sync_frame(struct mt_device *td, struct input_dev *input)
{
    input_mt_sync_frame(input);
    input_sync(input);
    td->num_received = 0;
}

static int mt_event(struct hid_device *hid, struct hid_field *field,
                struct hid_usage *usage, __s32 value)
{
    struct mt_device *td = hid_get_drvdata(hid);
    __s32 quirks = td->mtclass.quirks;

    if (hid->claimed & HID_CLAIMED_INPUT) {
        switch (usage->hid) {
        case HID_DG_INRANGE:
            if (quirks & MT_QUIRK_ALWAYS_VALID)
                td->curvalid = true;
            else if (quirks & MT_QUIRK_VALID_IS_INRANGE)
                td->curvalid = value;
            break;
        case HID_DG_TIPSWITCH:
            if (quirks & MT_QUIRK_NOT_SEEN_MEANS_UP)
                td->curvalid = value;
            td->curdata.touch_state = value;
            break;
        case HID_DG_CONFIDENCE:
            if (quirks & MT_QUIRK_VALID_IS_CONFIDENCE)
                td->curvalid = value;
            break;
        case HID_DG_CONTACTID:
            td->curdata.contactid = value;
            break;
        case HID_DG_TIPPRESSURE:
            td->curdata.p = value;
            break;
        case HID_GD_X:
            td->curdata.x = value;
            break;
        case HID_GD_Y:
            td->curdata.y = value;
            break;
        case HID_DG_WIDTH:
            td->curdata.w = value;
            break;
        case HID_DG_HEIGHT:
            td->curdata.h = value;
            break;
        case HID_DG_CONTACTCOUNT:
            /*
             * Includes multi-packet support where subsequent
             * packets are sent with zero contactcount.
             */
            if (value)
                td->num_expected = value;
            break;
        case HID_DG_TOUCH:
            /* do nothing */
            break;

        default:
            /* fallback to the generic hidinput handling */
            return 0;
        }

        if (usage->hid == td->last_slot_field)
            mt_complete_slot(td, field->hidinput->input);

        if (field->index == td->last_field_index
            && td->num_received >= td->num_expected)
            mt_sync_frame(td, field->hidinput->input);

    }

    /* we have handled the hidinput part, now remains hiddev */
    if (hid->claimed & HID_CLAIMED_HIDDEV && hid->hiddev_hid_event)
        hid->hiddev_hid_event(hid, field, usage, value);

    return 1;
}

static void mt_set_input_mode(struct hid_device *hdev)
{
    struct mt_device *td = hid_get_drvdata(hdev);
    struct hid_report *r;
    struct hid_report_enum *re;

    if (td->inputmode < 0)
        return;

    re = &(hdev->report_enum[HID_FEATURE_REPORT]);
    r = re->report_id_hash[td->inputmode];
    if (r) {
        r->field[0]->value[td->inputmode_index] = 0x02;
        usbhid_submit_report(hdev, r, USB_DIR_OUT);
    }
}

static void mt_set_maxcontacts(struct hid_device *hdev)
{
    struct mt_device *td = hid_get_drvdata(hdev);
    struct hid_report *r;
    struct hid_report_enum *re;
    int fieldmax, max;

    if (td->maxcontact_report_id < 0)
        return;

    if (!td->mtclass.maxcontacts)
        return;

    re = &hdev->report_enum[HID_FEATURE_REPORT];
    r = re->report_id_hash[td->maxcontact_report_id];
    if (r) {
        max = td->mtclass.maxcontacts;
        fieldmax = r->field[0]->logical_maximum;
        max = min(fieldmax, max);
        if (r->field[0]->value[0] != max) {
            r->field[0]->value[0] = max;
            usbhid_submit_report(hdev, r, USB_DIR_OUT);
        }
    }
}

static void mt_post_parse_default_settings(struct mt_device *td)
{
    __s32 quirks = td->mtclass.quirks;

    /* unknown serial device needs special quirks */
    if (td->touches_by_report == 1) {
        quirks |= MT_QUIRK_ALWAYS_VALID;
        quirks &= ~MT_QUIRK_NOT_SEEN_MEANS_UP;
        quirks &= ~MT_QUIRK_VALID_IS_INRANGE;
        quirks &= ~MT_QUIRK_VALID_IS_CONFIDENCE;
    }

    td->mtclass.quirks = quirks;
}

static void mt_post_parse(struct mt_device *td)
{
    struct mt_fields *f = td->fields;

    if (td->touches_by_report > 0) {
        int field_count_per_touch = f->length / td->touches_by_report;
        td->last_slot_field = f->usages[field_count_per_touch - 1];
    }
}

static void mt_input_configured(struct hid_device *hdev, struct hid_input *hi)

{
    struct mt_device *td = hid_get_drvdata(hdev);
    struct mt_class *cls = &td->mtclass;
    struct input_dev *input = hi->input;

    /* Only initialize slots for MT input devices */
    if (!test_bit(ABS_MT_POSITION_X, input->absbit))
        return;

    if (!td->maxcontacts)
        td->maxcontacts = MT_DEFAULT_MAXCONTACT;

    mt_post_parse(td);
    if (td->serial_maybe)
        mt_post_parse_default_settings(td);

    if (cls->is_indirect)
        td->mt_flags |= INPUT_MT_POINTER;

    if (cls->quirks & MT_QUIRK_NOT_SEEN_MEANS_UP)
        td->mt_flags |= INPUT_MT_DROP_UNUSED;

    input_mt_init_slots(input, td->maxcontacts, td->mt_flags);

    td->mt_flags = 0;
}

static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
    int ret, i;
    struct mt_device *td;
    struct mt_class *mtclass = mt_classes; /* MT_CLS_DEFAULT */

    for (i = 0; mt_classes[i].name ; i++) {
        if (id->driver_data == mt_classes[i].name) {
            mtclass = &(mt_classes[i]);
            break;
        }
    }

    /* This allows the driver to correctly support devices
     * that emit events over several HID messages.
     */
    hdev->quirks |= HID_QUIRK_NO_INPUT_SYNC;

    td = kzalloc(sizeof(struct mt_device), GFP_KERNEL);
    if (!td) {
        dev_err(&hdev->dev, "cannot allocate multitouch data\n");
        return -ENOMEM;
    }
    td->mtclass = *mtclass;
    td->inputmode = -1;
    td->maxcontact_report_id = -1;
    hid_set_drvdata(hdev, td);

    td->fields = kzalloc(sizeof(struct mt_fields), GFP_KERNEL);
    if (!td->fields) {
        dev_err(&hdev->dev, "cannot allocate multitouch fields data\n");
        ret = -ENOMEM;
        goto fail;
    }

    if (id->vendor == HID_ANY_ID && id->product == HID_ANY_ID)
        td->serial_maybe = true;

    ret = hid_parse(hdev);
    if (ret != 0)
        goto fail;

    ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
    if (ret)
        goto fail;

    ret = sysfs_create_group(&hdev->dev.kobj, &mt_attribute_group);

    mt_set_maxcontacts(hdev);
    mt_set_input_mode(hdev);

    kfree(td->fields);
    td->fields = NULL;

    return 0;

fail:
    kfree(td->fields);
    kfree(td);
    return ret;
}

#ifdef CONFIG_PM
static int mt_reset_resume(struct hid_device *hdev)
{
    mt_set_maxcontacts(hdev);
    mt_set_input_mode(hdev);
    return 0;
}

static int mt_resume(struct hid_device *hdev)
{
    struct usb_interface *intf;
    struct usb_host_interface *interface;
    struct usb_device *dev;

    if (hdev->bus != BUS_USB)
        return 0;

    intf = to_usb_interface(hdev->dev.parent);
    interface = intf->cur_altsetting;
    dev = hid_to_usb_dev(hdev);

    /* Some Elan legacy devices require SET_IDLE to be set on resume.
     * It should be safe to send it to other devices too.
     * Tested on 3M, Stantum, Cypress, Zytronic, eGalax, and Elan panels. */

    usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
            HID_REQ_SET_IDLE,
            USB_TYPE_CLASS | USB_RECIP_INTERFACE,
            0, interface->desc.bInterfaceNumber,
            NULL, 0, USB_CTRL_SET_TIMEOUT);

    return 0;
}
#endif

static void mt_remove(struct hid_device *hdev)
{
    struct mt_device *td = hid_get_drvdata(hdev);
    sysfs_remove_group(&hdev->dev.kobj, &mt_attribute_group);
    hid_hw_stop(hdev);
    kfree(td);
    hid_set_drvdata(hdev, NULL);
}

static const struct hid_device_id mt_devices[] = {

    /* 3M panels */
    { .driver_data = MT_CLS_3M,
        MT_USB_DEVICE(USB_VENDOR_ID_3M,
            USB_DEVICE_ID_3M1968) },
    { .driver_data = MT_CLS_3M,
        MT_USB_DEVICE(USB_VENDOR_ID_3M,
            USB_DEVICE_ID_3M2256) },
    { .driver_data = MT_CLS_3M,
        MT_USB_DEVICE(USB_VENDOR_ID_3M,
            USB_DEVICE_ID_3M3266) },

    /* ActionStar panels */
    { .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_ACTIONSTAR,
            USB_DEVICE_ID_ACTIONSTAR_1011) },

    /* Atmel panels */
    { .driver_data = MT_CLS_SERIAL,
        MT_USB_DEVICE(USB_VENDOR_ID_ATMEL,
            USB_DEVICE_ID_ATMEL_MULTITOUCH) },
    { .driver_data = MT_CLS_SERIAL,
        MT_USB_DEVICE(USB_VENDOR_ID_ATMEL,
            USB_DEVICE_ID_ATMEL_MXT_DIGITIZER) },

    /* Baanto multitouch devices */
    { .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_BAANTO,
            USB_DEVICE_ID_BAANTO_MT_190W2) },
    /* Cando panels */
    { .driver_data = MT_CLS_DUAL_INRANGE_CONTACTNUMBER,
        MT_USB_DEVICE(USB_VENDOR_ID_CANDO,
            USB_DEVICE_ID_CANDO_MULTI_TOUCH) },
    { .driver_data = MT_CLS_DUAL_INRANGE_CONTACTNUMBER,
        MT_USB_DEVICE(USB_VENDOR_ID_CANDO,
            USB_DEVICE_ID_CANDO_MULTI_TOUCH_10_1) },
    { .driver_data = MT_CLS_DUAL_INRANGE_CONTACTNUMBER,
        MT_USB_DEVICE(USB_VENDOR_ID_CANDO,
            USB_DEVICE_ID_CANDO_MULTI_TOUCH_11_6) },
    { .driver_data = MT_CLS_DUAL_INRANGE_CONTACTNUMBER,
        MT_USB_DEVICE(USB_VENDOR_ID_CANDO,
            USB_DEVICE_ID_CANDO_MULTI_TOUCH_15_6) },

    /* Chunghwa Telecom touch panels */
    {  .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_CHUNGHWAT,
            USB_DEVICE_ID_CHUNGHWAT_MULTITOUCH) },

    /* CVTouch panels */
    { .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_CVTOUCH,
            USB_DEVICE_ID_CVTOUCH_SCREEN) },

    /* Cypress panel */
    { .driver_data = MT_CLS_CYPRESS,
        HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS,
            USB_DEVICE_ID_CYPRESS_TRUETOUCH) },

    /* eGalax devices (resistive) */
    { .driver_data = MT_CLS_EGALAX,
        MT_USB_DEVICE(USB_VENDOR_ID_DWAV,
            USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH_480D) },
    { .driver_data = MT_CLS_EGALAX,
        MT_USB_DEVICE(USB_VENDOR_ID_DWAV,
            USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH_480E) },

    /* eGalax devices (capacitive) */
    { .driver_data = MT_CLS_EGALAX,
        MT_USB_DEVICE(USB_VENDOR_ID_DWAV,
            USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH_720C) },
    { .driver_data = MT_CLS_EGALAX_SERIAL,
        MT_USB_DEVICE(USB_VENDOR_ID_DWAV,
            USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH_7207) },
    { .driver_data = MT_CLS_EGALAX_SERIAL,
        MT_USB_DEVICE(USB_VENDOR_ID_DWAV,
            USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH_725E) },
    { .driver_data = MT_CLS_EGALAX_SERIAL,
        MT_USB_DEVICE(USB_VENDOR_ID_DWAV,
            USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH_7224) },
    { .driver_data = MT_CLS_EGALAX_SERIAL,
        MT_USB_DEVICE(USB_VENDOR_ID_DWAV,
            USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH_722A) },
    { .driver_data = MT_CLS_EGALAX,
        MT_USB_DEVICE(USB_VENDOR_ID_DWAV,
            USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH_726B) },
    { .driver_data = MT_CLS_EGALAX_SERIAL,
        MT_USB_DEVICE(USB_VENDOR_ID_DWAV,
            USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH_7262) },
    { .driver_data = MT_CLS_EGALAX,
        MT_USB_DEVICE(USB_VENDOR_ID_DWAV,
            USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH_72A1) },
    { .driver_data = MT_CLS_EGALAX_SERIAL,
        MT_USB_DEVICE(USB_VENDOR_ID_DWAV,
            USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH_72AA) },
    { .driver_data = MT_CLS_EGALAX,
        MT_USB_DEVICE(USB_VENDOR_ID_DWAV,
            USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH_72FA) },
    { .driver_data = MT_CLS_EGALAX,
        MT_USB_DEVICE(USB_VENDOR_ID_DWAV,
            USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH_7302) },
    { .driver_data = MT_CLS_EGALAX_SERIAL,
        MT_USB_DEVICE(USB_VENDOR_ID_DWAV,
            USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH_7349) },
    { .driver_data = MT_CLS_EGALAX_SERIAL,
        MT_USB_DEVICE(USB_VENDOR_ID_DWAV,
            USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH_73F7) },
    { .driver_data = MT_CLS_EGALAX_SERIAL,
        MT_USB_DEVICE(USB_VENDOR_ID_DWAV,
            USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH_A001) },
    { .driver_data = MT_CLS_EGALAX,
        HID_USB_DEVICE(USB_VENDOR_ID_DWAV,
            USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH_7224) },
    { .driver_data = MT_CLS_EGALAX,
        HID_USB_DEVICE(USB_VENDOR_ID_DWAV,
            USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH_72D0) },
    { .driver_data = MT_CLS_EGALAX,
        HID_USB_DEVICE(USB_VENDOR_ID_DWAV,
            USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH_72C4) },

    /* Elo TouchSystems IntelliTouch Plus panel */
    { .driver_data = MT_CLS_DUAL_NSMU_CONTACTID,
        MT_USB_DEVICE(USB_VENDOR_ID_ELO,
            USB_DEVICE_ID_ELO_TS2515) },

    /* Flatfrog Panels */
    { .driver_data = MT_CLS_FLATFROG,
        MT_USB_DEVICE(USB_VENDOR_ID_FLATFROG,
            USB_DEVICE_ID_MULTITOUCH_3200) },

    /* GeneralTouch panel */
    { .driver_data = MT_CLS_GENERALTOUCH_TWOFINGERS,
        MT_USB_DEVICE(USB_VENDOR_ID_GENERAL_TOUCH,
            USB_DEVICE_ID_GENERAL_TOUCH_WIN7_TWOFINGERS) },
    { .driver_data = MT_CLS_GENERALTOUCH_PWT_TENFINGERS,
        MT_USB_DEVICE(USB_VENDOR_ID_GENERAL_TOUCH,
            USB_DEVICE_ID_GENERAL_TOUCH_WIN8_PWT_TENFINGERS) },

    /* Gametel game controller */
    { .driver_data = MT_CLS_DEFAULT,
        MT_BT_DEVICE(USB_VENDOR_ID_FRUCTEL,
            USB_DEVICE_ID_GAMETEL_MT_MODE) },

    /* GoodTouch panels */
    { .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_GOODTOUCH,
            USB_DEVICE_ID_GOODTOUCH_000f) },

    /* Hanvon panels */
    { .driver_data = MT_CLS_DUAL_INRANGE_CONTACTID,
        MT_USB_DEVICE(USB_VENDOR_ID_HANVON_ALT,
            USB_DEVICE_ID_HANVON_ALT_MULTITOUCH) },

    /* Ideacom panel */
    { .driver_data = MT_CLS_SERIAL,
        MT_USB_DEVICE(USB_VENDOR_ID_IDEACOM,
            USB_DEVICE_ID_IDEACOM_IDC6650) },
    { .driver_data = MT_CLS_SERIAL,
        MT_USB_DEVICE(USB_VENDOR_ID_IDEACOM,
            USB_DEVICE_ID_IDEACOM_IDC6651) },

    /* Ilitek dual touch panel */
    {  .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_ILITEK,
            USB_DEVICE_ID_ILITEK_MULTITOUCH) },

    /* IRTOUCH panels */
    { .driver_data = MT_CLS_DUAL_INRANGE_CONTACTID,
        MT_USB_DEVICE(USB_VENDOR_ID_IRTOUCHSYSTEMS,
            USB_DEVICE_ID_IRTOUCH_INFRARED_USB) },

    /* LG Display panels */
    { .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_LG,
            USB_DEVICE_ID_LG_MULTITOUCH) },

    /* Lumio panels */
    { .driver_data = MT_CLS_CONFIDENCE_MINUS_ONE,
        MT_USB_DEVICE(USB_VENDOR_ID_LUMIO,
            USB_DEVICE_ID_CRYSTALTOUCH) },
    { .driver_data = MT_CLS_CONFIDENCE_MINUS_ONE,
        MT_USB_DEVICE(USB_VENDOR_ID_LUMIO,
            USB_DEVICE_ID_CRYSTALTOUCH_DUAL) },

    /* MosArt panels */
    { .driver_data = MT_CLS_CONFIDENCE_MINUS_ONE,
        MT_USB_DEVICE(USB_VENDOR_ID_ASUS,
            USB_DEVICE_ID_ASUS_T91MT)},
    { .driver_data = MT_CLS_CONFIDENCE_MINUS_ONE,
        MT_USB_DEVICE(USB_VENDOR_ID_ASUS,
            USB_DEVICE_ID_ASUSTEK_MULTITOUCH_YFO) },
    { .driver_data = MT_CLS_CONFIDENCE_MINUS_ONE,
        MT_USB_DEVICE(USB_VENDOR_ID_TURBOX,
            USB_DEVICE_ID_TURBOX_TOUCHSCREEN_MOSART) },

    /* Panasonic panels */
    { .driver_data = MT_CLS_PANASONIC,
        MT_USB_DEVICE(USB_VENDOR_ID_PANASONIC,
            USB_DEVICE_ID_PANABOARD_UBT780) },
    { .driver_data = MT_CLS_PANASONIC,
        MT_USB_DEVICE(USB_VENDOR_ID_PANASONIC,
            USB_DEVICE_ID_PANABOARD_UBT880) },

    /* Novatek Panel */
    { .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_NOVATEK,
            USB_DEVICE_ID_NOVATEK_PCT) },

    /* PenMount panels */
    { .driver_data = MT_CLS_CONFIDENCE,
        MT_USB_DEVICE(USB_VENDOR_ID_PENMOUNT,
            USB_DEVICE_ID_PENMOUNT_PCI) },

    /* PixArt optical touch screen */
    { .driver_data = MT_CLS_INRANGE_CONTACTNUMBER,
        MT_USB_DEVICE(USB_VENDOR_ID_PIXART,
            USB_DEVICE_ID_PIXART_OPTICAL_TOUCH_SCREEN) },
    { .driver_data = MT_CLS_INRANGE_CONTACTNUMBER,
        MT_USB_DEVICE(USB_VENDOR_ID_PIXART,
            USB_DEVICE_ID_PIXART_OPTICAL_TOUCH_SCREEN1) },
    { .driver_data = MT_CLS_INRANGE_CONTACTNUMBER,
        MT_USB_DEVICE(USB_VENDOR_ID_PIXART,
            USB_DEVICE_ID_PIXART_OPTICAL_TOUCH_SCREEN2) },

    /* PixCir-based panels */
    { .driver_data = MT_CLS_DUAL_INRANGE_CONTACTID,
        MT_USB_DEVICE(USB_VENDOR_ID_HANVON,
            USB_DEVICE_ID_HANVON_MULTITOUCH) },
    { .driver_data = MT_CLS_DUAL_INRANGE_CONTACTID,
        MT_USB_DEVICE(USB_VENDOR_ID_CANDO,
            USB_DEVICE_ID_CANDO_PIXCIR_MULTI_TOUCH) },

    /* Quanta-based panels */
    { .driver_data = MT_CLS_CONFIDENCE_CONTACT_ID,
        MT_USB_DEVICE(USB_VENDOR_ID_QUANTA,
            USB_DEVICE_ID_QUANTA_OPTICAL_TOUCH) },
    { .driver_data = MT_CLS_CONFIDENCE_CONTACT_ID,
        MT_USB_DEVICE(USB_VENDOR_ID_QUANTA,
            USB_DEVICE_ID_QUANTA_OPTICAL_TOUCH_3001) },
    { .driver_data = MT_CLS_CONFIDENCE_CONTACT_ID,
        MT_USB_DEVICE(USB_VENDOR_ID_QUANTA,
            USB_DEVICE_ID_QUANTA_OPTICAL_TOUCH_3008) },

    /* Stantum panels */
    { .driver_data = MT_CLS_CONFIDENCE,
        MT_USB_DEVICE(USB_VENDOR_ID_STANTUM,
            USB_DEVICE_ID_MTP)},
    { .driver_data = MT_CLS_CONFIDENCE,
        MT_USB_DEVICE(USB_VENDOR_ID_STANTUM_STM,
            USB_DEVICE_ID_MTP_STM)},
    { .driver_data = MT_CLS_CONFIDENCE,
        MT_USB_DEVICE(USB_VENDOR_ID_STANTUM_SITRONIX,
            USB_DEVICE_ID_MTP_SITRONIX)},

    /* TopSeed panels */
    { .driver_data = MT_CLS_TOPSEED,
        MT_USB_DEVICE(USB_VENDOR_ID_TOPSEED2,
            USB_DEVICE_ID_TOPSEED2_PERIPAD_701) },

    /* Touch International panels */
    { .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_TOUCH_INTL,
            USB_DEVICE_ID_TOUCH_INTL_MULTI_TOUCH) },

    /* Unitec panels */
    { .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_UNITEC,
            USB_DEVICE_ID_UNITEC_USB_TOUCH_0709) },
    { .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_UNITEC,
            USB_DEVICE_ID_UNITEC_USB_TOUCH_0A19) },
    /* XAT */
    { .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_XAT,
            USB_DEVICE_ID_XAT_CSR) },

    /* Xiroku */
    { .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_XIROKU,
            USB_DEVICE_ID_XIROKU_SPX) },
    { .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_XIROKU,
            USB_DEVICE_ID_XIROKU_MPX) },
    { .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_XIROKU,
            USB_DEVICE_ID_XIROKU_CSR) },
    { .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_XIROKU,
            USB_DEVICE_ID_XIROKU_SPX1) },
    { .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_XIROKU,
            USB_DEVICE_ID_XIROKU_MPX1) },
    { .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_XIROKU,
            USB_DEVICE_ID_XIROKU_CSR1) },
    { .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_XIROKU,
            USB_DEVICE_ID_XIROKU_SPX2) },
    { .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_XIROKU,
            USB_DEVICE_ID_XIROKU_MPX2) },
    { .driver_data = MT_CLS_DEFAULT,
        MT_USB_DEVICE(USB_VENDOR_ID_XIROKU,
            USB_DEVICE_ID_XIROKU_CSR2) },

    /* Zytronic panels */
    { .driver_data = MT_CLS_SERIAL,
        MT_USB_DEVICE(USB_VENDOR_ID_ZYTRONIC,
            USB_DEVICE_ID_ZYTRONIC_ZXY100) },

    /* Generic MT device */
    { HID_DEVICE(HID_BUS_ANY, HID_GROUP_MULTITOUCH, HID_ANY_ID, HID_ANY_ID) },
    { }
};
MODULE_DEVICE_TABLE(hid, mt_devices);

static const struct hid_usage_id mt_grabbed_usages[] = {
    { HID_ANY_ID, HID_ANY_ID, HID_ANY_ID },
    { HID_ANY_ID - 1, HID_ANY_ID - 1, HID_ANY_ID - 1}
};

static struct hid_driver mt_driver = {
    .name = "hid-multitouch",
    .id_table = mt_devices,
    .probe = mt_probe,
    .remove = mt_remove,
    .input_mapping = mt_input_mapping,
    .input_mapped = mt_input_mapped,
    .input_configured = mt_input_configured,
    .feature_mapping = mt_feature_mapping,
    .usage_table = mt_grabbed_usages,
    .event = mt_event,
#ifdef CONFIG_PM
    .reset_resume = mt_reset_resume,
    .resume = mt_resume,
#endif
};

static int __init mt_init(void)
{
    return hid_register_driver(&mt_driver);
}

static void __exit mt_exit(void)
{
    hid_unregister_driver(&mt_driver);
}

module_init(mt_init);
module_exit(mt_exit);