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 */ 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 */ 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 */ 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 */ 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 */ 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