/*
* 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/slab.h>
#define TRKID_SGN ((TRKID_MAX + 1) >> 1)
/**
* 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
*
* 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.
* 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)
{
int i;
if (!num_slots)
return 0;
if (dev->mt)
return dev->mtsize != num_slots ? -EINVAL : 0;
dev->mt = kcalloc(num_slots, sizeof(struct input_mt_slot), GFP_KERNEL);
if (!dev->mt)
return -ENOMEM;
dev->mtsize = num_slots;
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);
input_set_events_per_packet(dev, 6 * num_slots);
/* Mark slots as 'unused' */
for (i = 0; i < num_slots; i++)
input_mt_set_value(&dev->mt[i], ABS_MT_TRACKING_ID, -1);
return 0;
}
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)
{
kfree(dev->mt);
dev->mt = NULL;
dev->mtsize = 0;
dev->slot = 0;
dev->trkid = 0;
}
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.
*/
void input_mt_report_slot_state(struct input_dev *dev,
unsigned int tool_type, bool active)
{
struct input_mt_slot *mt;
int id;
if (!dev->mt || !active) {
input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
return;
}
mt = &dev->mt[dev->slot];
id = input_mt_get_value(mt, ABS_MT_TRACKING_ID);
if (id < 0 || input_mt_get_value(mt, ABS_MT_TOOL_TYPE) != tool_type)
id = input_mt_new_trkid(dev);
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);
/**
* 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);
}
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_slot *oldest = 0;
int oldid = dev->trkid;
int count = 0;
int i;
for (i = 0; i < dev->mtsize; ++i) {
struct input_mt_slot *ps = &dev->mt[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);
int p = input_mt_get_value(oldest, ABS_MT_PRESSURE);
input_event(dev, EV_ABS, ABS_X, x);
input_event(dev, EV_ABS, ABS_Y, y);
input_event(dev, EV_ABS, ABS_PRESSURE, p);
} else {
input_event(dev, EV_ABS, ABS_PRESSURE, 0);
}
}
EXPORT_SYMBOL(input_mt_report_pointer_emulation);
