projects/linux·blob v3.6 · refs

172 lines · 5.1 KiB

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/export.h>
13#include <linux/slab.h>
14
15#define TRKID_SGN ((TRKID_MAX + 1) >> 1)
16
17/**
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
21 *
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.
27 */
28int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots)
29{
30 int i;
31
32 if (!num_slots)
33 return 0;
34 if (dev->mt)
35 return dev->mtsize != num_slots ? -EINVAL : 0;
36
37 dev->mt = kcalloc(num_slots, sizeof(struct input_mt_slot), GFP_KERNEL);
38 if (!dev->mt)
39 return -ENOMEM;
40
41 dev->mtsize = num_slots;
42 input_set_abs_params(dev, ABS_MT_SLOT, 0, num_slots - 1, 0, 0);
43 input_set_abs_params(dev, ABS_MT_TRACKING_ID, 0, TRKID_MAX, 0, 0);
44 input_set_events_per_packet(dev, 6 * num_slots);
45
46 /* Mark slots as 'unused' */
47 for (i = 0; i < num_slots; i++)
48 input_mt_set_value(&dev->mt[i], ABS_MT_TRACKING_ID, -1);
49
50 return 0;
51}
52EXPORT_SYMBOL(input_mt_init_slots);
53
54/**
55 * input_mt_destroy_slots() - frees the MT slots of the input device
56 * @dev: input device with allocated MT slots
57 *
58 * This function is only needed in error path as the input core will
59 * automatically free the MT slots when the device is destroyed.
60 */
61void input_mt_destroy_slots(struct input_dev *dev)
62{
63 kfree(dev->mt);
64 dev->mt = NULL;
65 dev->mtsize = 0;
66 dev->slot = 0;
67 dev->trkid = 0;
68}
69EXPORT_SYMBOL(input_mt_destroy_slots);
70
71/**
72 * input_mt_report_slot_state() - report contact state
73 * @dev: input device with allocated MT slots
74 * @tool_type: the tool type to use in this slot
75 * @active: true if contact is active, false otherwise
76 *
77 * Reports a contact via ABS_MT_TRACKING_ID, and optionally
78 * ABS_MT_TOOL_TYPE. If active is true and the slot is currently
79 * inactive, or if the tool type is changed, a new tracking id is
80 * assigned to the slot. The tool type is only reported if the
81 * corresponding absbit field is set.
82 */
83void input_mt_report_slot_state(struct input_dev *dev,
84 unsigned int tool_type, bool active)
85{
86 struct input_mt_slot *mt;
87 int id;
88
89 if (!dev->mt || !active) {
90 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
91 return;
92 }
93
94 mt = &dev->mt[dev->slot];
95 id = input_mt_get_value(mt, ABS_MT_TRACKING_ID);
96 if (id < 0 || input_mt_get_value(mt, ABS_MT_TOOL_TYPE) != tool_type)
97 id = input_mt_new_trkid(dev);
98
99 input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, id);
100 input_event(dev, EV_ABS, ABS_MT_TOOL_TYPE, tool_type);
101}
102EXPORT_SYMBOL(input_mt_report_slot_state);
103
104/**
105 * input_mt_report_finger_count() - report contact count
106 * @dev: input device with allocated MT slots
107 * @count: the number of contacts
108 *
109 * Reports the contact count via BTN_TOOL_FINGER, BTN_TOOL_DOUBLETAP,
110 * BTN_TOOL_TRIPLETAP and BTN_TOOL_QUADTAP.
111 *
112 * The input core ensures only the KEY events already setup for
113 * this device will produce output.
114 */
115void input_mt_report_finger_count(struct input_dev *dev, int count)
116{
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);
122}
123EXPORT_SYMBOL(input_mt_report_finger_count);
124
125/**
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
129 *
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.
132 *
133 * The input core ensures only the KEY and ABS axes already setup for
134 * this device will produce output.
135 */
136void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count)
137{
138 struct input_mt_slot *oldest = NULL;
139 int oldid = dev->trkid;
140 int count = 0;
141 int i;
142
143 for (i = 0; i < dev->mtsize; ++i) {
144 struct input_mt_slot *ps = &dev->mt[i];
145 int id = input_mt_get_value(ps, ABS_MT_TRACKING_ID);
146
147 if (id < 0)
148 continue;
149 if ((id - oldid) & TRKID_SGN) {
150 oldest = ps;
151 oldid = id;
152 }
153 count++;
154 }
155
156 input_event(dev, EV_KEY, BTN_TOUCH, count > 0);
157 if (use_count)
158 input_mt_report_finger_count(dev, count);
159
160 if (oldest) {
161 int x = input_mt_get_value(oldest, ABS_MT_POSITION_X);
162 int y = input_mt_get_value(oldest, ABS_MT_POSITION_Y);
163 int p = input_mt_get_value(oldest, ABS_MT_PRESSURE);
164
165 input_event(dev, EV_ABS, ABS_X, x);
166 input_event(dev, EV_ABS, ABS_Y, y);
167 input_event(dev, EV_ABS, ABS_PRESSURE, p);
168 } else {
169 input_event(dev, EV_ABS, ABS_PRESSURE, 0);
170 }
171}
172EXPORT_SYMBOL(input_mt_report_pointer_emulation);