2 * Input Multitouch Library
4 * Copyright (c) 2008-2010 Henrik Rydberg
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.
11 #include <linux/input/mt.h>
12 #include <linux/export.h>
13 #include <linux/slab.h>
15 #define TRKID_SGN ((TRKID_MAX + 1) >> 1)
18 * input_mt_init_slots() - initialize MT input slots
19 * @dev: input device supporting MT events and finger tracking
20 * @num_slots: number of slots used by the device
22 * This function allocates all necessary memory for MT slot handling
23 * in the input device, prepares the ABS_MT_SLOT and
24 * ABS_MT_TRACKING_ID events for use and sets up appropriate buffers.
25 * May be called repeatedly. Returns -EINVAL if attempting to
26 * reinitialize with a different number of slots.
28 int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots)
30 struct input_mt *mt = dev->mt;
36 return mt->num_slots != num_slots ? -EINVAL : 0;
38 mt = kzalloc(sizeof(*mt) + num_slots * sizeof(*mt->slots), GFP_KERNEL);
42 mt->num_slots = num_slots;
43 input_set_abs_params(dev, ABS_MT_SLOT, 0, num_slots - 1, 0, 0);
44 input_set_abs_params(dev, ABS_MT_TRACKING_ID, 0, TRKID_MAX, 0, 0);
45 input_set_events_per_packet(dev, 6 * num_slots);
47 /* Mark slots as 'unused' */
48 for (i = 0; i < num_slots; i++)
49 input_mt_set_value(&mt->slots[i], ABS_MT_TRACKING_ID, -1);
54 EXPORT_SYMBOL(input_mt_init_slots);
57 * input_mt_destroy_slots() - frees the MT slots of the input device
58 * @dev: input device with allocated MT slots
60 * This function is only needed in error path as the input core will
61 * automatically free the MT slots when the device is destroyed.
63 void input_mt_destroy_slots(struct input_dev *dev)
68 EXPORT_SYMBOL(input_mt_destroy_slots);
71 * input_mt_report_slot_state() - report contact state
72 * @dev: input device with allocated MT slots
73 * @tool_type: the tool type to use in this slot
74 * @active: true if contact is active, false otherwise
76 * Reports a contact via ABS_MT_TRACKING_ID, and optionally
77 * ABS_MT_TOOL_TYPE. If active is true and the slot is currently
78 * inactive, or if the tool type is changed, a new tracking id is
79 * assigned to the slot. The tool type is only reported if the
80 * corresponding absbit field is set.
82 void input_mt_report_slot_state(struct input_dev *dev,
83 unsigned int tool_type, bool active)
85 struct input_mt *mt = dev->mt;
86 struct input_mt_slot *slot;
90 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
94 slot = &mt->slots[mt->slot];
95 id = input_mt_get_value(slot, ABS_MT_TRACKING_ID);
96 if (id < 0 || input_mt_get_value(slot, ABS_MT_TOOL_TYPE) != tool_type)
97 id = input_mt_new_trkid(mt);
99 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, id);
100 input_event(dev, EV_ABS, ABS_MT_TOOL_TYPE, tool_type);
102 EXPORT_SYMBOL(input_mt_report_slot_state);
105 * input_mt_report_finger_count() - report contact count
106 * @dev: input device with allocated MT slots
107 * @count: the number of contacts
109 * Reports the contact count via BTN_TOOL_FINGER, BTN_TOOL_DOUBLETAP,
110 * BTN_TOOL_TRIPLETAP and BTN_TOOL_QUADTAP.
112 * The input core ensures only the KEY events already setup for
113 * this device will produce output.
115 void input_mt_report_finger_count(struct input_dev *dev, int count)
117 input_event(dev, EV_KEY, BTN_TOOL_FINGER, count == 1);
118 input_event(dev, EV_KEY, BTN_TOOL_DOUBLETAP, count == 2);
119 input_event(dev, EV_KEY, BTN_TOOL_TRIPLETAP, count == 3);
120 input_event(dev, EV_KEY, BTN_TOOL_QUADTAP, count == 4);
121 input_event(dev, EV_KEY, BTN_TOOL_QUINTTAP, count == 5);
123 EXPORT_SYMBOL(input_mt_report_finger_count);
126 * input_mt_report_pointer_emulation() - common pointer emulation
127 * @dev: input device with allocated MT slots
128 * @use_count: report number of active contacts as finger count
130 * Performs legacy pointer emulation via BTN_TOUCH, ABS_X, ABS_Y and
131 * ABS_PRESSURE. Touchpad finger count is emulated if use_count is true.
133 * The input core ensures only the KEY and ABS axes already setup for
134 * this device will produce output.
136 void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count)
138 struct input_mt *mt = dev->mt;
139 struct input_mt_slot *oldest;
149 for (i = 0; i < mt->num_slots; ++i) {
150 struct input_mt_slot *ps = &mt->slots[i];
151 int id = input_mt_get_value(ps, ABS_MT_TRACKING_ID);
155 if ((id - oldid) & TRKID_SGN) {
162 input_event(dev, EV_KEY, BTN_TOUCH, count > 0);
164 input_mt_report_finger_count(dev, count);
167 int x = input_mt_get_value(oldest, ABS_MT_POSITION_X);
168 int y = input_mt_get_value(oldest, ABS_MT_POSITION_Y);
169 int p = input_mt_get_value(oldest, ABS_MT_PRESSURE);
171 input_event(dev, EV_ABS, ABS_X, x);
172 input_event(dev, EV_ABS, ABS_Y, y);
173 input_event(dev, EV_ABS, ABS_PRESSURE, p);
175 input_event(dev, EV_ABS, ABS_PRESSURE, 0);
178 EXPORT_SYMBOL(input_mt_report_pointer_emulation);