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 */ 28 int 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 } 52 EXPORT_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 */ 61 void 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 } 69 EXPORT_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 */ 83 void 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 } 102 EXPORT_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 */ 115 void 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 } 123 EXPORT_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 */ 136 void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count) 137 { 138 struct input_mt_slot *oldest = 0; 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 } 172 EXPORT_SYMBOL(input_mt_report_pointer_emulation); 173