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47c78e89 HR |
1 | /* |
2 | * Input Multitouch Library | |
3 | * | |
4 | * Copyright (c) 2008-2010 Henrik Rydberg | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify it | |
7 | * under the terms of the GNU General Public License version 2 as published by | |
8 | * the Free Software Foundation. | |
9 | */ | |
10 | ||
11 | #include <linux/input/mt.h> | |
12 | #include <linux/slab.h> | |
13 | ||
14 | /** | |
15 | * input_mt_create_slots() - create MT input slots | |
16 | * @dev: input device supporting MT events and finger tracking | |
17 | * @num_slots: number of slots used by the device | |
18 | * | |
19 | * This function allocates all necessary memory for MT slot handling in the | |
20 | * input device, and adds ABS_MT_SLOT to the device capabilities. All slots | |
21 | * are initially marked as unused by setting ABS_MT_TRACKING_ID to -1. | |
22 | */ | |
23 | int input_mt_create_slots(struct input_dev *dev, unsigned int num_slots) | |
24 | { | |
25 | int i; | |
26 | ||
27 | if (!num_slots) | |
28 | return 0; | |
29 | ||
30 | dev->mt = kcalloc(num_slots, sizeof(struct input_mt_slot), GFP_KERNEL); | |
31 | if (!dev->mt) | |
32 | return -ENOMEM; | |
33 | ||
34 | dev->mtsize = num_slots; | |
35 | input_set_abs_params(dev, ABS_MT_SLOT, 0, num_slots - 1, 0, 0); | |
36 | ||
37 | /* Mark slots as 'unused' */ | |
38 | for (i = 0; i < num_slots; i++) | |
39 | input_mt_set_value(&dev->mt[i], ABS_MT_TRACKING_ID, -1); | |
40 | ||
41 | return 0; | |
42 | } | |
43 | EXPORT_SYMBOL(input_mt_create_slots); | |
44 | ||
45 | /** | |
46 | * input_mt_destroy_slots() - frees the MT slots of the input device | |
47 | * @dev: input device with allocated MT slots | |
48 | * | |
49 | * This function is only needed in error path as the input core will | |
50 | * automatically free the MT slots when the device is destroyed. | |
51 | */ | |
52 | void input_mt_destroy_slots(struct input_dev *dev) | |
53 | { | |
54 | kfree(dev->mt); | |
55 | dev->mt = NULL; | |
56 | dev->mtsize = 0; | |
57 | } | |
58 | EXPORT_SYMBOL(input_mt_destroy_slots); |