// SPDX-License-Identifier: GPL-2.0-only
/*
* Input Multitouch Library
*
* Copyright (c) 2008-2010 Henrik Rydberg
*/
#include <linux/input/mt.h>
#include <linux/export.h>
#include <linux/slab.h>
#include "input-core-private.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->absinfo[dst].fuzz = 0;
__set_bit(dst, dev->absbit);
}
}
/**
* input_mt_init_slots() - initialize MT input slots
* @dev: input device supporting MT events and finger tracking
* @num_slots: number of slots used by the device
* @flags: mt tasks to handle in core
*
* This function allocates all necessary memory for MT slot handling
* in the input device, prepares the ABS_MT_SLOT and
* ABS_MT_TRACKING_ID events for use and sets up appropriate buffers.
* Depending on the flags set, it also performs pointer emulation and
* frame synchronization.
*
* May be called repeatedly. Returns -EINVAL if attempting to
* reinitialize with a different number of slots.
*/
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;
/* Arbitrary limit for avoiding too large memory allocation. */
if (num_slots > 1024)
return -EINVAL;
mt = kzalloc(struct_size(mt, slots, num_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_SEMI_MT)
__set_bit(INPUT_PROP_SEMI_MT, 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 'inactive' */
for (i = 0; i < num_slots; i++)
input_mt_set_value(&mt->slots[i], ABS_MT_TRACKING_ID, -1);
/* Mark slots as 'unused' */
mt->frame = 1;
dev->mt = mt;
return 0;
err_mem:
kfree(mt);
return -ENOMEM;
}
EXPORT_SYMBOL(input_mt_init_slots);
/**
* input_mt_destroy_slots() - frees the MT slots of the input device
* @dev: input device with allocated MT slots
*
* This function is only needed in error path as the input core will
* automatically free the MT slots when the device is destroyed.
*/
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);
/**
* input_mt_report_slot_state() - report contact state
* @dev: input device with allocated MT slots
* @tool_type: the tool type to use in this slot
* @active: true if contact is active, false otherwise
*
* Reports a contact via ABS_MT_TRACKING_ID, and optionally
* ABS_MT_TOOL_TYPE. If active is true and the slot is currently
* inactive, or if the tool type is changed, a new tracking id is
* assigned to the slot. The tool type is only reported if the
* corresponding absbit field is set.
*
* Returns true if contact is active.
*/
bool 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 false;
slot = &mt->slots[mt->slot];
slot->frame = mt->frame;
if (!active) {
input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
return false;
}
id = input_mt_get_value(slot, ABS_MT_TRACKING_ID);
if (id < 0)
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);
return true;
}
EXPORT_SYMBOL(input_mt_report_slot_state);
/**
* input_mt_report_finger_count() - report contact count
* @dev: input device with allocated MT slots
* @count: the number of contacts
*
* Reports the contact count via BTN_TOOL_FINGER, BTN_TOOL_DOUBLETAP,
* BTN_TOOL_TRIPLETAP and BTN_TOOL_QUADTAP.
*
* The input core ensures only the KEY events already setup for
* this device will produce output.
*/
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);
/**
* input_mt_report_pointer_emulation() - common pointer emulation
* @dev: input device with allocated MT slots
* @use_count: report number of active contacts as finger count
*
* Performs legacy pointer emulation via BTN_TOUCH, ABS_X, ABS_Y and
* ABS_PRESSURE. Touchpad finger count is emulated if use_count is true.
*
* The input core ensures only the KEY and ABS axes already setup for
* this device will produce output.
*/
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 = NULL;
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) {
if (count == 0 &&
!test_bit(ABS_MT_DISTANCE, dev->absbit) &&
test_bit(ABS_DISTANCE, dev->absbit) &&
input_abs_get_val(dev, ABS_DISTANCE) != 0) {
/*
* Force reporting BTN_TOOL_FINGER for devices that
* only report general hover (and not per-contact
* distance) when contact is in proximity but not
* on the surface.
*/
count = 1;
}
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);
static void __input_mt_drop_unused(struct input_dev *dev, struct input_mt *mt)
{
int i;
lockdep_assert_held(&dev->event_lock);
for (i = 0; i < mt->num_slots; i++) {
if (input_mt_is_active(&mt->slots[i]) &&
!input_mt_is_used(mt, &mt->slots[i])) {
input_handle_event(dev, EV_ABS, ABS_MT_SLOT, i);
input_handle_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
}
}
}
/**
* input_mt_drop_unused() - Inactivate slots not seen in this frame
* @dev: input device with allocated MT slots
*
* Lift all slots not seen since the last call to this function.
*/
void input_mt_drop_unused(struct input_dev *dev)
{
struct input_mt *mt = dev->mt;
if (mt) {
unsigned long flags;
spin_lock_irqsave(&dev->event_lock, flags);
__input_mt_drop_unused(dev, mt);
mt->frame++;
spin_unlock_irqrestore(&dev->event_lock, flags);
}
}
EXPORT_SYMBOL(input_mt_drop_unused);
/**
* input_mt_release_slots() - Deactivate all slots
* @dev: input device with allocated MT slots
*
* Lift all active slots.
*/
void input_mt_release_slots(struct input_dev *dev)
{
struct input_mt *mt = dev->mt;
lockdep_assert_held(&dev->event_lock);
if (mt) {
/* This will effectively mark all slots unused. */
mt->frame++;
__input_mt_drop_unused(dev, mt);
if (test_bit(ABS_PRESSURE, dev->absbit))
input_handle_event(dev, EV_ABS, ABS_PRESSURE, 0);
mt->frame++;
}
}
/**
* input_mt_sync_frame() - synchronize mt frame
* @dev: input device with allocated MT slots
*
* Close the frame and prepare the internal state for a new one.
* Depending on the flags, marks unused slots as inactive and performs
* pointer emulation.
*/
void input_mt_sync_frame(struct input_dev *dev)
{
struct input_mt *mt = dev->mt;
bool use_count = false;
if (!mt)
return;
if (mt->flags & INPUT_MT_DROP_UNUSED) {
unsigned long flags;
spin_lock_irqsave(&dev->event_lock, flags);
__input_mt_drop_unused(dev, mt);
spin_unlock_irqrestore(&dev->event_lock, flags);
}
if ((mt->flags & INPUT_MT_POINTER) && !(mt->flags & INPUT_MT_SEMI_MT))
use_count = true;
input_mt_report_pointer_emulation(dev, use_count);
mt->frame++;
}
EXPORT_SYMBOL(input_mt_sync_frame);
static int adjust_dual(int *begin, int step, int *end, int eq, int mu)
{
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 > mu && (!eq || mu > 0)))
return 0;
/* Improve convergence for positive matrices by penalizing overcovers */
if (s < 0 && mu <= 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 mu)
{
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, mu);
sum = 0;
for (i = 0; i < nrc; i += nr)
sum += adjust_dual(w + i, 1, w + i + nr, nc <= nr, mu);
if (!sum)
break;
}
}
static int input_mt_set_matrix(struct input_mt *mt,
const struct input_mt_pos *pos, int num_pos,
int mu)
{
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 - mu;
}
}
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, j;
for (j = 0; j != num_pos; j++)
slots[j] = -1;
for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
if (!input_mt_is_active(s))
continue;
for (j = 0; j != num_pos; j++) {
if (w[j] < 0) {
slots[j] = s - mt->slots;
break;
}
}
w += num_pos;
}
for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
if (input_mt_is_active(s))
continue;
for (j = 0; j != num_pos; j++) {
if (slots[j] < 0) {
slots[j] = s - mt->slots;
break;
}
}
}
}
/**
* input_mt_assign_slots() - perform a best-match assignment
* @dev: input device with allocated MT slots
* @slots: the slot assignment to be filled
* @pos: the position array to match
* @num_pos: number of positions
* @dmax: maximum ABS_MT_POSITION displacement (zero for infinite)
*
* Performs a best match against the current contacts and returns
* the slot assignment list. New contacts are assigned to unused
* slots.
*
* The assignments are balanced so that all coordinate displacements are
* below the euclidian distance dmax. If no such assignment can be found,
* some contacts are assigned to unused slots.
*
* Returns zero on success, or negative error in case of failure.
*/
int input_mt_assign_slots(struct input_dev *dev, int *slots,
const struct input_mt_pos *pos, int num_pos,
int dmax)
{
struct input_mt *mt = dev->mt;
int mu = 2 * dmax * dmax;
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, mu);
find_reduced_matrix(mt->red, num_pos, nrc / num_pos, nrc, mu);
input_mt_set_slots(mt, slots, num_pos);
return 0;
}
EXPORT_SYMBOL(input_mt_assign_slots);
/**
* input_mt_get_slot_by_key() - return slot matching key
* @dev: input device with allocated MT slots
* @key: the key of the sought slot
*
* Returns the slot of the given key, if it exists, otherwise
* set the key on the first unused slot and return.
*
* If no available slot can be found, -1 is returned.
* Note that for this function to work properly, input_mt_sync_frame() has
* to be called at each frame.
*/
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) && !input_mt_is_used(mt, s)) {
s->key = key;
return s - mt->slots;
}
return -1;
}
EXPORT_SYMBOL(input_mt_get_slot_by_key);
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