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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/slab.h>
/**
* input_mt_create_slots() - create 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, and adds ABS_MT_SLOT to the device capabilities. All slots
* are initially marked as unused by setting ABS_MT_TRACKING_ID to -1.
*/
int input_mt_create_slots(struct input_dev *dev, unsigned int num_slots)
{
int i;
if (!num_slots)
return 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);
/* 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_create_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;
}
EXPORT_SYMBOL(input_mt_destroy_slots);
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