| Henrik Rydberg | 47c78e8 | 2010-11-27 09:16:48 +0100 | [diff] [blame^] | 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); |