diff options
Diffstat (limited to 'drivers/input/input-mt.c')
| -rw-r--r-- | drivers/input/input-mt.c | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c new file mode 100644 index 00000000000..463a4d7d54f --- /dev/null +++ b/drivers/input/input-mt.c @@ -0,0 +1,58 @@ +/* + * 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); |