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)
17 static void copy_abs(struct input_dev
*dev
, unsigned int dst
, unsigned int src
)
19 if (dev
->absinfo
&& test_bit(src
, dev
->absbit
)) {
20 dev
->absinfo
[dst
] = dev
->absinfo
[src
];
21 dev
->absinfo
[dst
].fuzz
= 0;
22 dev
->absbit
[BIT_WORD(dst
)] |= BIT_MASK(dst
);
27 * input_mt_init_slots() - initialize MT input slots
28 * @dev: input device supporting MT events and finger tracking
29 * @num_slots: number of slots used by the device
30 * @flags: mt tasks to handle in core
32 * This function allocates all necessary memory for MT slot handling
33 * in the input device, prepares the ABS_MT_SLOT and
34 * ABS_MT_TRACKING_ID events for use and sets up appropriate buffers.
35 * Depending on the flags set, it also performs pointer emulation and
36 * frame synchronization.
38 * May be called repeatedly. Returns -EINVAL if attempting to
39 * reinitialize with a different number of slots.
41 int input_mt_init_slots(struct input_dev
*dev
, unsigned int num_slots
,
44 struct input_mt
*mt
= dev
->mt
;
50 return mt
->num_slots
!= num_slots
? -EINVAL
: 0;
52 mt
= kzalloc(sizeof(*mt
) + num_slots
* sizeof(*mt
->slots
), GFP_KERNEL
);
56 mt
->num_slots
= num_slots
;
58 input_set_abs_params(dev
, ABS_MT_SLOT
, 0, num_slots
- 1, 0, 0);
59 input_set_abs_params(dev
, ABS_MT_TRACKING_ID
, 0, TRKID_MAX
, 0, 0);
61 if (flags
& (INPUT_MT_POINTER
| INPUT_MT_DIRECT
)) {
62 __set_bit(EV_KEY
, dev
->evbit
);
63 __set_bit(BTN_TOUCH
, dev
->keybit
);
65 copy_abs(dev
, ABS_X
, ABS_MT_POSITION_X
);
66 copy_abs(dev
, ABS_Y
, ABS_MT_POSITION_Y
);
67 copy_abs(dev
, ABS_PRESSURE
, ABS_MT_PRESSURE
);
69 if (flags
& INPUT_MT_POINTER
) {
70 __set_bit(BTN_TOOL_FINGER
, dev
->keybit
);
71 __set_bit(BTN_TOOL_DOUBLETAP
, dev
->keybit
);
73 __set_bit(BTN_TOOL_TRIPLETAP
, dev
->keybit
);
75 __set_bit(BTN_TOOL_QUADTAP
, dev
->keybit
);
77 __set_bit(BTN_TOOL_QUINTTAP
, dev
->keybit
);
78 __set_bit(INPUT_PROP_POINTER
, dev
->propbit
);
80 if (flags
& INPUT_MT_DIRECT
)
81 __set_bit(INPUT_PROP_DIRECT
, dev
->propbit
);
82 if (flags
& INPUT_MT_SEMI_MT
)
83 __set_bit(INPUT_PROP_SEMI_MT
, dev
->propbit
);
84 if (flags
& INPUT_MT_TRACK
) {
85 unsigned int n2
= num_slots
* num_slots
;
86 mt
->red
= kcalloc(n2
, sizeof(*mt
->red
), GFP_KERNEL
);
91 /* Mark slots as 'unused' */
92 for (i
= 0; i
< num_slots
; i
++)
93 input_mt_set_value(&mt
->slots
[i
], ABS_MT_TRACKING_ID
, -1);
101 EXPORT_SYMBOL(input_mt_init_slots
);
104 * input_mt_destroy_slots() - frees the MT slots of the input device
105 * @dev: input device with allocated MT slots
107 * This function is only needed in error path as the input core will
108 * automatically free the MT slots when the device is destroyed.
110 void input_mt_destroy_slots(struct input_dev
*dev
)
118 EXPORT_SYMBOL(input_mt_destroy_slots
);
121 * input_mt_report_slot_state() - report contact state
122 * @dev: input device with allocated MT slots
123 * @tool_type: the tool type to use in this slot
124 * @active: true if contact is active, false otherwise
126 * Reports a contact via ABS_MT_TRACKING_ID, and optionally
127 * ABS_MT_TOOL_TYPE. If active is true and the slot is currently
128 * inactive, or if the tool type is changed, a new tracking id is
129 * assigned to the slot. The tool type is only reported if the
130 * corresponding absbit field is set.
132 void input_mt_report_slot_state(struct input_dev
*dev
,
133 unsigned int tool_type
, bool active
)
135 struct input_mt
*mt
= dev
->mt
;
136 struct input_mt_slot
*slot
;
142 slot
= &mt
->slots
[mt
->slot
];
143 slot
->frame
= mt
->frame
;
146 input_event(dev
, EV_ABS
, ABS_MT_TRACKING_ID
, -1);
150 id
= input_mt_get_value(slot
, ABS_MT_TRACKING_ID
);
151 if (id
< 0 || input_mt_get_value(slot
, ABS_MT_TOOL_TYPE
) != tool_type
)
152 id
= input_mt_new_trkid(mt
);
154 input_event(dev
, EV_ABS
, ABS_MT_TRACKING_ID
, id
);
155 input_event(dev
, EV_ABS
, ABS_MT_TOOL_TYPE
, tool_type
);
157 EXPORT_SYMBOL(input_mt_report_slot_state
);
160 * input_mt_report_finger_count() - report contact count
161 * @dev: input device with allocated MT slots
162 * @count: the number of contacts
164 * Reports the contact count via BTN_TOOL_FINGER, BTN_TOOL_DOUBLETAP,
165 * BTN_TOOL_TRIPLETAP and BTN_TOOL_QUADTAP.
167 * The input core ensures only the KEY events already setup for
168 * this device will produce output.
170 void input_mt_report_finger_count(struct input_dev
*dev
, int count
)
172 input_event(dev
, EV_KEY
, BTN_TOOL_FINGER
, count
== 1);
173 input_event(dev
, EV_KEY
, BTN_TOOL_DOUBLETAP
, count
== 2);
174 input_event(dev
, EV_KEY
, BTN_TOOL_TRIPLETAP
, count
== 3);
175 input_event(dev
, EV_KEY
, BTN_TOOL_QUADTAP
, count
== 4);
176 input_event(dev
, EV_KEY
, BTN_TOOL_QUINTTAP
, count
== 5);
178 EXPORT_SYMBOL(input_mt_report_finger_count
);
181 * input_mt_report_pointer_emulation() - common pointer emulation
182 * @dev: input device with allocated MT slots
183 * @use_count: report number of active contacts as finger count
185 * Performs legacy pointer emulation via BTN_TOUCH, ABS_X, ABS_Y and
186 * ABS_PRESSURE. Touchpad finger count is emulated if use_count is true.
188 * The input core ensures only the KEY and ABS axes already setup for
189 * this device will produce output.
191 void input_mt_report_pointer_emulation(struct input_dev
*dev
, bool use_count
)
193 struct input_mt
*mt
= dev
->mt
;
194 struct input_mt_slot
*oldest
;
204 for (i
= 0; i
< mt
->num_slots
; ++i
) {
205 struct input_mt_slot
*ps
= &mt
->slots
[i
];
206 int id
= input_mt_get_value(ps
, ABS_MT_TRACKING_ID
);
210 if ((id
- oldid
) & TRKID_SGN
) {
217 input_event(dev
, EV_KEY
, BTN_TOUCH
, count
> 0);
219 input_mt_report_finger_count(dev
, count
);
222 int x
= input_mt_get_value(oldest
, ABS_MT_POSITION_X
);
223 int y
= input_mt_get_value(oldest
, ABS_MT_POSITION_Y
);
225 input_event(dev
, EV_ABS
, ABS_X
, x
);
226 input_event(dev
, EV_ABS
, ABS_Y
, y
);
228 if (test_bit(ABS_MT_PRESSURE
, dev
->absbit
)) {
229 int p
= input_mt_get_value(oldest
, ABS_MT_PRESSURE
);
230 input_event(dev
, EV_ABS
, ABS_PRESSURE
, p
);
233 if (test_bit(ABS_MT_PRESSURE
, dev
->absbit
))
234 input_event(dev
, EV_ABS
, ABS_PRESSURE
, 0);
237 EXPORT_SYMBOL(input_mt_report_pointer_emulation
);
239 static void __input_mt_drop_unused(struct input_dev
*dev
, struct input_mt
*mt
)
243 for (i
= 0; i
< mt
->num_slots
; i
++) {
244 if (!input_mt_is_used(mt
, &mt
->slots
[i
])) {
245 input_mt_slot(dev
, i
);
246 input_event(dev
, EV_ABS
, ABS_MT_TRACKING_ID
, -1);
252 * input_mt_drop_unused() - Inactivate slots not seen in this frame
253 * @dev: input device with allocated MT slots
255 * Lift all slots not seen since the last call to this function.
257 void input_mt_drop_unused(struct input_dev
*dev
)
259 struct input_mt
*mt
= dev
->mt
;
262 __input_mt_drop_unused(dev
, mt
);
266 EXPORT_SYMBOL(input_mt_drop_unused
);
269 * input_mt_sync_frame() - synchronize mt frame
270 * @dev: input device with allocated MT slots
272 * Close the frame and prepare the internal state for a new one.
273 * Depending on the flags, marks unused slots as inactive and performs
276 void input_mt_sync_frame(struct input_dev
*dev
)
278 struct input_mt
*mt
= dev
->mt
;
279 bool use_count
= false;
284 if (mt
->flags
& INPUT_MT_DROP_UNUSED
)
285 __input_mt_drop_unused(dev
, mt
);
287 if ((mt
->flags
& INPUT_MT_POINTER
) && !(mt
->flags
& INPUT_MT_SEMI_MT
))
290 input_mt_report_pointer_emulation(dev
, use_count
);
294 EXPORT_SYMBOL(input_mt_sync_frame
);
296 static int adjust_dual(int *begin
, int step
, int *end
, int eq
, int mu
)
305 s
= p
== end
? f
+ 1 : *p
;
307 for (; p
!= end
; p
+= step
)
314 if (c
== 0 || (c
> mu
&& (!eq
|| mu
> 0)))
316 /* Improve convergence for positive matrices by penalizing overcovers */
317 if (s
< 0 && mu
<= 0)
320 for (p
= begin
; p
!= end
; p
+= step
)
323 return (c
< s
&& s
<= 0) || (f
>= 0 && f
< c
);
326 static void find_reduced_matrix(int *w
, int nr
, int nc
, int nrc
, int mu
)
330 for (k
= 0; k
< nrc
; k
++) {
331 for (i
= 0; i
< nr
; i
++)
332 adjust_dual(w
+ i
, nr
, w
+ i
+ nrc
, nr
<= nc
, mu
);
334 for (i
= 0; i
< nrc
; i
+= nr
)
335 sum
+= adjust_dual(w
+ i
, 1, w
+ i
+ nr
, nc
<= nr
, mu
);
341 static int input_mt_set_matrix(struct input_mt
*mt
,
342 const struct input_mt_pos
*pos
, int num_pos
,
345 const struct input_mt_pos
*p
;
346 struct input_mt_slot
*s
;
350 for (s
= mt
->slots
; s
!= mt
->slots
+ mt
->num_slots
; s
++) {
351 if (!input_mt_is_active(s
))
353 x
= input_mt_get_value(s
, ABS_MT_POSITION_X
);
354 y
= input_mt_get_value(s
, ABS_MT_POSITION_Y
);
355 for (p
= pos
; p
!= pos
+ num_pos
; p
++) {
356 int dx
= x
- p
->x
, dy
= y
- p
->y
;
357 *w
++ = dx
* dx
+ dy
* dy
- mu
;
364 static void input_mt_set_slots(struct input_mt
*mt
,
365 int *slots
, int num_pos
)
367 struct input_mt_slot
*s
;
370 for (j
= 0; j
!= num_pos
; j
++)
373 for (s
= mt
->slots
; s
!= mt
->slots
+ mt
->num_slots
; s
++) {
374 if (!input_mt_is_active(s
))
377 for (j
= 0; j
!= num_pos
; j
++) {
379 slots
[j
] = s
- mt
->slots
;
387 for (s
= mt
->slots
; s
!= mt
->slots
+ mt
->num_slots
; s
++) {
388 if (input_mt_is_active(s
))
391 for (j
= 0; j
!= num_pos
; j
++) {
393 slots
[j
] = s
- mt
->slots
;
401 * input_mt_assign_slots() - perform a best-match assignment
402 * @dev: input device with allocated MT slots
403 * @slots: the slot assignment to be filled
404 * @pos: the position array to match
405 * @num_pos: number of positions
406 * @dmax: maximum ABS_MT_POSITION displacement (zero for infinite)
408 * Performs a best match against the current contacts and returns
409 * the slot assignment list. New contacts are assigned to unused
412 * The assignments are balanced so that all coordinate displacements are
413 * below the euclidian distance dmax. If no such assignment can be found,
414 * some contacts are assigned to unused slots.
416 * Returns zero on success, or negative error in case of failure.
418 int input_mt_assign_slots(struct input_dev
*dev
, int *slots
,
419 const struct input_mt_pos
*pos
, int num_pos
,
422 struct input_mt
*mt
= dev
->mt
;
423 int mu
= 2 * dmax
* dmax
;
428 if (num_pos
> mt
->num_slots
)
433 nrc
= input_mt_set_matrix(mt
, pos
, num_pos
, mu
);
434 find_reduced_matrix(mt
->red
, num_pos
, nrc
/ num_pos
, nrc
, mu
);
435 input_mt_set_slots(mt
, slots
, num_pos
);
439 EXPORT_SYMBOL(input_mt_assign_slots
);
442 * input_mt_get_slot_by_key() - return slot matching key
443 * @dev: input device with allocated MT slots
444 * @key: the key of the sought slot
446 * Returns the slot of the given key, if it exists, otherwise
447 * set the key on the first unused slot and return.
449 * If no available slot can be found, -1 is returned.
451 int input_mt_get_slot_by_key(struct input_dev
*dev
, int key
)
453 struct input_mt
*mt
= dev
->mt
;
454 struct input_mt_slot
*s
;
459 for (s
= mt
->slots
; s
!= mt
->slots
+ mt
->num_slots
; s
++)
460 if (input_mt_is_active(s
) && s
->key
== key
)
461 return s
- mt
->slots
;
463 for (s
= mt
->slots
; s
!= mt
->slots
+ mt
->num_slots
; s
++)
464 if (!input_mt_is_active(s
)) {
466 return s
- mt
->slots
;
471 EXPORT_SYMBOL(input_mt_get_slot_by_key
);