input-mt.c

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/*
 * Input Multitouch Library
 *
 * Copyright (c) 2008-2010 Henrik Rydberg
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */

#include <linux/input/mt.h>
#include <linux/export.h>
#include <linux/slab.h>

#define TRKID_SGN   ((TRKID_MAX + 1) >> 1)

static void copy_abs(struct input_dev *dev, unsigned int dst, unsigned int src)
{
    if (dev->absinfo && test_bit(src, dev->absbit)) {
        dev->absinfo[dst] = dev->absinfo[src];
        dev->absbit[BIT_WORD(dst)] |= BIT_MASK(dst);
    }
}

int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots,
            unsigned int flags)
{
    struct input_mt *mt = dev->mt;
    int i;

    if (!num_slots)
        return 0;
    if (mt)
        return mt->num_slots != num_slots ? -EINVAL : 0;

    mt = kzalloc(sizeof(*mt) + num_slots * sizeof(*mt->slots), GFP_KERNEL);
    if (!mt)
        goto err_mem;

    mt->num_slots = num_slots;
    mt->flags = flags;
    input_set_abs_params(dev, ABS_MT_SLOT, 0, num_slots - 1, 0, 0);
    input_set_abs_params(dev, ABS_MT_TRACKING_ID, 0, TRKID_MAX, 0, 0);

    if (flags & (INPUT_MT_POINTER | INPUT_MT_DIRECT)) {
        __set_bit(EV_KEY, dev->evbit);
        __set_bit(BTN_TOUCH, dev->keybit);

        copy_abs(dev, ABS_X, ABS_MT_POSITION_X);
        copy_abs(dev, ABS_Y, ABS_MT_POSITION_Y);
        copy_abs(dev, ABS_PRESSURE, ABS_MT_PRESSURE);
    }
    if (flags & INPUT_MT_POINTER) {
        __set_bit(BTN_TOOL_FINGER, dev->keybit);
        __set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
        if (num_slots >= 3)
            __set_bit(BTN_TOOL_TRIPLETAP, dev->keybit);
        if (num_slots >= 4)
            __set_bit(BTN_TOOL_QUADTAP, dev->keybit);
        if (num_slots >= 5)
            __set_bit(BTN_TOOL_QUINTTAP, dev->keybit);
        __set_bit(INPUT_PROP_POINTER, dev->propbit);
    }
    if (flags & INPUT_MT_DIRECT)
        __set_bit(INPUT_PROP_DIRECT, dev->propbit);
    if (flags & INPUT_MT_TRACK) {
        unsigned int n2 = num_slots * num_slots;
        mt->red = kcalloc(n2, sizeof(*mt->red), GFP_KERNEL);
        if (!mt->red)
            goto err_mem;
    }

    /* Mark slots as 'unused' */
    for (i = 0; i < num_slots; i++)
        input_mt_set_value(&mt->slots[i], ABS_MT_TRACKING_ID, -1);

    dev->mt = mt;
    return 0;
err_mem:
    kfree(mt);
    return -ENOMEM;
}
EXPORT_SYMBOL(input_mt_init_slots);

void input_mt_destroy_slots(struct input_dev *dev)
{
    if (dev->mt) {
        kfree(dev->mt->red);
        kfree(dev->mt);
    }
    dev->mt = NULL;
}
EXPORT_SYMBOL(input_mt_destroy_slots);

void input_mt_report_slot_state(struct input_dev *dev,
                unsigned int tool_type, bool active)
{
    struct input_mt *mt = dev->mt;
    struct input_mt_slot *slot;
    int id;

    if (!mt)
        return;

    slot = &mt->slots[mt->slot];
    slot->frame = mt->frame;

    if (!active) {
        input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
        return;
    }

    id = input_mt_get_value(slot, ABS_MT_TRACKING_ID);
    if (id < 0 || input_mt_get_value(slot, ABS_MT_TOOL_TYPE) != tool_type)
        id = input_mt_new_trkid(mt);

    input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, id);
    input_event(dev, EV_ABS, ABS_MT_TOOL_TYPE, tool_type);
}
EXPORT_SYMBOL(input_mt_report_slot_state);

void input_mt_report_finger_count(struct input_dev *dev, int count)
{
    input_event(dev, EV_KEY, BTN_TOOL_FINGER, count == 1);
    input_event(dev, EV_KEY, BTN_TOOL_DOUBLETAP, count == 2);
    input_event(dev, EV_KEY, BTN_TOOL_TRIPLETAP, count == 3);
    input_event(dev, EV_KEY, BTN_TOOL_QUADTAP, count == 4);
    input_event(dev, EV_KEY, BTN_TOOL_QUINTTAP, count == 5);
}
EXPORT_SYMBOL(input_mt_report_finger_count);

void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count)
{
    struct input_mt *mt = dev->mt;
    struct input_mt_slot *oldest;
    int oldid, count, i;

    if (!mt)
        return;

    oldest = 0;
    oldid = mt->trkid;
    count = 0;

    for (i = 0; i < mt->num_slots; ++i) {
        struct input_mt_slot *ps = &mt->slots[i];
        int id = input_mt_get_value(ps, ABS_MT_TRACKING_ID);

        if (id < 0)
            continue;
        if ((id - oldid) & TRKID_SGN) {
            oldest = ps;
            oldid = id;
        }
        count++;
    }

    input_event(dev, EV_KEY, BTN_TOUCH, count > 0);
    if (use_count)
        input_mt_report_finger_count(dev, count);

    if (oldest) {
        int x = input_mt_get_value(oldest, ABS_MT_POSITION_X);
        int y = input_mt_get_value(oldest, ABS_MT_POSITION_Y);

        input_event(dev, EV_ABS, ABS_X, x);
        input_event(dev, EV_ABS, ABS_Y, y);

        if (test_bit(ABS_MT_PRESSURE, dev->absbit)) {
            int p = input_mt_get_value(oldest, ABS_MT_PRESSURE);
            input_event(dev, EV_ABS, ABS_PRESSURE, p);
        }
    } else {
        if (test_bit(ABS_MT_PRESSURE, dev->absbit))
            input_event(dev, EV_ABS, ABS_PRESSURE, 0);
    }
}
EXPORT_SYMBOL(input_mt_report_pointer_emulation);

void input_mt_sync_frame(struct input_dev *dev)
{
    struct input_mt *mt = dev->mt;
    struct input_mt_slot *s;

    if (!mt)
        return;

    if (mt->flags & INPUT_MT_DROP_UNUSED) {
        for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
            if (s->frame == mt->frame)
                continue;
            input_mt_slot(dev, s - mt->slots);
            input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
        }
    }

    input_mt_report_pointer_emulation(dev, (mt->flags & INPUT_MT_POINTER));

    mt->frame++;
}
EXPORT_SYMBOL(input_mt_sync_frame);

static int adjust_dual(int *begin, int step, int *end, int eq)
{
    int f, *p, s, c;

    if (begin == end)
        return 0;

    f = *begin;
    p = begin + step;
    s = p == end ? f + 1 : *p;

    for (; p != end; p += step)
        if (*p < f)
            s = f, f = *p;
        else if (*p < s)
            s = *p;

    c = (f + s + 1) / 2;
    if (c == 0 || (c > 0 && !eq))
        return 0;
    if (s < 0)
        c *= 2;

    for (p = begin; p != end; p += step)
        *p -= c;

    return (c < s && s <= 0) || (f >= 0 && f < c);
}

static void find_reduced_matrix(int *w, int nr, int nc, int nrc)
{
    int i, k, sum;

    for (k = 0; k < nrc; k++) {
        for (i = 0; i < nr; i++)
            adjust_dual(w + i, nr, w + i + nrc, nr <= nc);
        sum = 0;
        for (i = 0; i < nrc; i += nr)
            sum += adjust_dual(w + i, 1, w + i + nr, nc <= nr);
        if (!sum)
            break;
    }
}

static int input_mt_set_matrix(struct input_mt *mt,
                   const struct input_mt_pos *pos, int num_pos)
{
    const struct input_mt_pos *p;
    struct input_mt_slot *s;
    int *w = mt->red;
    int x, y;

    for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
        if (!input_mt_is_active(s))
            continue;
        x = input_mt_get_value(s, ABS_MT_POSITION_X);
        y = input_mt_get_value(s, ABS_MT_POSITION_Y);
        for (p = pos; p != pos + num_pos; p++) {
            int dx = x - p->x, dy = y - p->y;
            *w++ = dx * dx + dy * dy;
        }
    }

    return w - mt->red;
}

static void input_mt_set_slots(struct input_mt *mt,
                   int *slots, int num_pos)
{
    struct input_mt_slot *s;
    int *w = mt->red, *p;

    for (p = slots; p != slots + num_pos; p++)
        *p = -1;

    for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
        if (!input_mt_is_active(s))
            continue;
        for (p = slots; p != slots + num_pos; p++)
            if (*w++ < 0)
                *p = s - mt->slots;
    }

    for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
        if (input_mt_is_active(s))
            continue;
        for (p = slots; p != slots + num_pos; p++)
            if (*p < 0) {
                *p = s - mt->slots;
                break;
            }
    }
}

int input_mt_assign_slots(struct input_dev *dev, int *slots,
              const struct input_mt_pos *pos, int num_pos)
{
    struct input_mt *mt = dev->mt;
    int nrc;

    if (!mt || !mt->red)
        return -ENXIO;
    if (num_pos > mt->num_slots)
        return -EINVAL;
    if (num_pos < 1)
        return 0;

    nrc = input_mt_set_matrix(mt, pos, num_pos);
    find_reduced_matrix(mt->red, num_pos, nrc / num_pos, nrc);
    input_mt_set_slots(mt, slots, num_pos);

    return 0;
}
EXPORT_SYMBOL(input_mt_assign_slots);

int input_mt_get_slot_by_key(struct input_dev *dev, int key)
{
    struct input_mt *mt = dev->mt;
    struct input_mt_slot *s;

    if (!mt)
        return -1;

    for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
        if (input_mt_is_active(s) && s->key == key)
            return s - mt->slots;

    for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
        if (!input_mt_is_active(s)) {
            s->key = key;
            return s - mt->slots;
        }

    return -1;
}
EXPORT_SYMBOL(input_mt_get_slot_by_key);