59 lines
1.6 KiB
C
59 lines
1.6 KiB
C
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/*
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* Input Multitouch Library
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*
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* Copyright (c) 2008-2010 Henrik Rydberg
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*/
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#include <linux/input/mt.h>
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#include <linux/slab.h>
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/**
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* input_mt_create_slots() - create MT input slots
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* @dev: input device supporting MT events and finger tracking
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* @num_slots: number of slots used by the device
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*
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* This function allocates all necessary memory for MT slot handling in the
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* input device, and adds ABS_MT_SLOT to the device capabilities. All slots
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* are initially marked as unused by setting ABS_MT_TRACKING_ID to -1.
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*/
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int input_mt_create_slots(struct input_dev *dev, unsigned int num_slots)
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{
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int i;
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if (!num_slots)
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return 0;
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dev->mt = kcalloc(num_slots, sizeof(struct input_mt_slot), GFP_KERNEL);
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if (!dev->mt)
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return -ENOMEM;
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dev->mtsize = num_slots;
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input_set_abs_params(dev, ABS_MT_SLOT, 0, num_slots - 1, 0, 0);
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/* Mark slots as 'unused' */
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for (i = 0; i < num_slots; i++)
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input_mt_set_value(&dev->mt[i], ABS_MT_TRACKING_ID, -1);
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return 0;
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}
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EXPORT_SYMBOL(input_mt_create_slots);
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/**
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* input_mt_destroy_slots() - frees the MT slots of the input device
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* @dev: input device with allocated MT slots
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*
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* This function is only needed in error path as the input core will
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* automatically free the MT slots when the device is destroyed.
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*/
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void input_mt_destroy_slots(struct input_dev *dev)
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{
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kfree(dev->mt);
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dev->mt = NULL;
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dev->mtsize = 0;
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}
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EXPORT_SYMBOL(input_mt_destroy_slots);
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