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 #define TRKID_SGN ((TRKID_MAX + 1) >> 1)
15
16 /**
17 * input_mt_init_slots() - initialize MT input slots
18 * @dev: input device supporting MT events and finger tracking
19 * @num_slots: number of slots used by the device
20 *
21 * This function allocates all necessary memory for MT slot handling
22 * in the input device, prepares the ABS_MT_SLOT and
23 * ABS_MT_TRACKING_ID events for use and sets up appropriate buffers.
24 * May be called repeatedly. Returns -EINVAL if attempting to
25 * reinitialize with a different number of slots.
26 */
input_mt_init_slots(struct input_dev * dev,unsigned int num_slots)27 int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots)
28 {
29 int i;
30
31 if (!num_slots)
32 return 0;
33 if (dev->mt)
34 return dev->mtsize != num_slots ? -EINVAL : 0;
35
36 dev->mt = kcalloc(num_slots, sizeof(struct input_mt_slot), GFP_KERNEL);
37 if (!dev->mt)
38 return -ENOMEM;
39
40 dev->mtsize = num_slots;
41 input_set_abs_params(dev, ABS_MT_SLOT, 0, num_slots - 1, 0, 0);
42 input_set_abs_params(dev, ABS_MT_TRACKING_ID, 0, TRKID_MAX, 0, 0);
43 input_set_events_per_packet(dev, 6 * num_slots);
44
45 /* Mark slots as 'unused' */
46 for (i = 0; i < num_slots; i++)
47 input_mt_set_value(&dev->mt[i], ABS_MT_TRACKING_ID, -1);
48
49 return 0;
50 }
51 EXPORT_SYMBOL(input_mt_init_slots);
52
53 /**
54 * input_mt_destroy_slots() - frees the MT slots of the input device
55 * @dev: input device with allocated MT slots
56 *
57 * This function is only needed in error path as the input core will
58 * automatically free the MT slots when the device is destroyed.
59 */
input_mt_destroy_slots(struct input_dev * dev)60 void input_mt_destroy_slots(struct input_dev *dev)
61 {
62 kfree(dev->mt);
63 dev->mt = NULL;
64 dev->mtsize = 0;
65 dev->slot = 0;
66 dev->trkid = 0;
67 }
68 EXPORT_SYMBOL(input_mt_destroy_slots);
69
70 /**
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
75 *
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.
81 */
input_mt_report_slot_state(struct input_dev * dev,unsigned int tool_type,bool active)82 void input_mt_report_slot_state(struct input_dev *dev,
83 unsigned int tool_type, bool active)
84 {
85 struct input_mt_slot *mt;
86 int id;
87
88 if (!dev->mt || !active) {
89 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
90 return;
91 }
92
93 mt = &dev->mt[dev->slot];
94 id = input_mt_get_value(mt, ABS_MT_TRACKING_ID);
95 if (id < 0 || input_mt_get_value(mt, ABS_MT_TOOL_TYPE) != tool_type)
96 id = input_mt_new_trkid(dev);
97
98 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, id);
99 input_event(dev, EV_ABS, ABS_MT_TOOL_TYPE, tool_type);
100 }
101 EXPORT_SYMBOL(input_mt_report_slot_state);
102
103 /**
104 * input_mt_report_finger_count() - report contact count
105 * @dev: input device with allocated MT slots
106 * @count: the number of contacts
107 *
108 * Reports the contact count via BTN_TOOL_FINGER, BTN_TOOL_DOUBLETAP,
109 * BTN_TOOL_TRIPLETAP and BTN_TOOL_QUADTAP.
110 *
111 * The input core ensures only the KEY events already setup for
112 * this device will produce output.
113 */
input_mt_report_finger_count(struct input_dev * dev,int count)114 void input_mt_report_finger_count(struct input_dev *dev, int count)
115 {
116 input_event(dev, EV_KEY, BTN_TOOL_FINGER, count == 1);
117 input_event(dev, EV_KEY, BTN_TOOL_DOUBLETAP, count == 2);
118 input_event(dev, EV_KEY, BTN_TOOL_TRIPLETAP, count == 3);
119 input_event(dev, EV_KEY, BTN_TOOL_QUADTAP, count == 4);
120 }
121 EXPORT_SYMBOL(input_mt_report_finger_count);
122
123 /**
124 * input_mt_report_pointer_emulation() - common pointer emulation
125 * @dev: input device with allocated MT slots
126 * @use_count: report number of active contacts as finger count
127 *
128 * Performs legacy pointer emulation via BTN_TOUCH, ABS_X, ABS_Y and
129 * ABS_PRESSURE. Touchpad finger count is emulated if use_count is true.
130 *
131 * The input core ensures only the KEY and ABS axes already setup for
132 * this device will produce output.
133 */
input_mt_report_pointer_emulation(struct input_dev * dev,bool use_count)134 void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count)
135 {
136 struct input_mt_slot *oldest = 0;
137 int oldid = dev->trkid;
138 int count = 0;
139 int i;
140
141 for (i = 0; i < dev->mtsize; ++i) {
142 struct input_mt_slot *ps = &dev->mt[i];
143 int id = input_mt_get_value(ps, ABS_MT_TRACKING_ID);
144
145 if (id < 0)
146 continue;
147 if ((id - oldid) & TRKID_SGN) {
148 oldest = ps;
149 oldid = id;
150 }
151 count++;
152 }
153
154 input_event(dev, EV_KEY, BTN_TOUCH, count > 0);
155 if (use_count)
156 input_mt_report_finger_count(dev, count);
157
158 if (oldest) {
159 int x = input_mt_get_value(oldest, ABS_MT_POSITION_X);
160 int y = input_mt_get_value(oldest, ABS_MT_POSITION_Y);
161 int p = input_mt_get_value(oldest, ABS_MT_PRESSURE);
162
163 input_event(dev, EV_ABS, ABS_X, x);
164 input_event(dev, EV_ABS, ABS_Y, y);
165 input_event(dev, EV_ABS, ABS_PRESSURE, p);
166 } else {
167 input_event(dev, EV_ABS, ABS_PRESSURE, 0);
168 }
169 }
170 EXPORT_SYMBOL(input_mt_report_pointer_emulation);
171