xref: /linux/drivers/hid/hid-ntrig.c (revision d39d0ed196aa1685bb24771e92f78633c66ac9cb)
1 /*
2  *  HID driver for N-Trig touchscreens
3  *
4  *  Copyright (c) 2008-2010 Rafi Rubin
5  *  Copyright (c) 2009-2010 Stephane Chatty
6  *
7  */
8 
9 /*
10  * This program is free software; you can redistribute it and/or modify it
11  * under the terms of the GNU General Public License as published by the Free
12  * Software Foundation; either version 2 of the License, or (at your option)
13  * any later version.
14  */
15 
16 #include <linux/device.h>
17 #include <linux/hid.h>
18 #include <linux/usb.h>
19 #include "usbhid/usbhid.h"
20 #include <linux/module.h>
21 #include <linux/slab.h>
22 
23 #include "hid-ids.h"
24 
25 #define NTRIG_DUPLICATE_USAGES	0x001
26 
27 static unsigned int min_width;
28 module_param(min_width, uint, 0644);
29 MODULE_PARM_DESC(min_width, "Minimum touch contact width to accept.");
30 
31 static unsigned int min_height;
32 module_param(min_height, uint, 0644);
33 MODULE_PARM_DESC(min_height, "Minimum touch contact height to accept.");
34 
35 static unsigned int activate_slack = 1;
36 module_param(activate_slack, uint, 0644);
37 MODULE_PARM_DESC(activate_slack, "Number of touch frames to ignore at "
38 		 "the start of touch input.");
39 
40 static unsigned int deactivate_slack = 4;
41 module_param(deactivate_slack, uint, 0644);
42 MODULE_PARM_DESC(deactivate_slack, "Number of empty frames to ignore before "
43 		 "deactivating touch.");
44 
45 static unsigned int activation_width = 64;
46 module_param(activation_width, uint, 0644);
47 MODULE_PARM_DESC(activation_width, "Width threshold to immediately start "
48 		 "processing touch events.");
49 
50 static unsigned int activation_height = 32;
51 module_param(activation_height, uint, 0644);
52 MODULE_PARM_DESC(activation_height, "Height threshold to immediately start "
53 		 "processing touch events.");
54 
55 struct ntrig_data {
56 	/* Incoming raw values for a single contact */
57 	__u16 x, y, w, h;
58 	__u16 id;
59 
60 	bool tipswitch;
61 	bool confidence;
62 	bool first_contact_touch;
63 
64 	bool reading_mt;
65 
66 	__u8 mt_footer[4];
67 	__u8 mt_foot_count;
68 
69 	/* The current activation state. */
70 	__s8 act_state;
71 
72 	/* Empty frames to ignore before recognizing the end of activity */
73 	__s8 deactivate_slack;
74 
75 	/* Frames to ignore before acknowledging the start of activity */
76 	__s8 activate_slack;
77 
78 	/* Minimum size contact to accept */
79 	__u16 min_width;
80 	__u16 min_height;
81 
82 	/* Threshold to override activation slack */
83 	__u16 activation_width;
84 	__u16 activation_height;
85 
86 	__u16 sensor_logical_width;
87 	__u16 sensor_logical_height;
88 	__u16 sensor_physical_width;
89 	__u16 sensor_physical_height;
90 };
91 
92 
93 static ssize_t show_phys_width(struct device *dev,
94 			       struct device_attribute *attr,
95 			       char *buf)
96 {
97 	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
98 	struct ntrig_data *nd = hid_get_drvdata(hdev);
99 
100 	return sprintf(buf, "%d\n", nd->sensor_physical_width);
101 }
102 
103 static DEVICE_ATTR(sensor_physical_width, S_IRUGO, show_phys_width, NULL);
104 
105 static ssize_t show_phys_height(struct device *dev,
106 				struct device_attribute *attr,
107 				char *buf)
108 {
109 	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
110 	struct ntrig_data *nd = hid_get_drvdata(hdev);
111 
112 	return sprintf(buf, "%d\n", nd->sensor_physical_height);
113 }
114 
115 static DEVICE_ATTR(sensor_physical_height, S_IRUGO, show_phys_height, NULL);
116 
117 static ssize_t show_log_width(struct device *dev,
118 			      struct device_attribute *attr,
119 			      char *buf)
120 {
121 	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
122 	struct ntrig_data *nd = hid_get_drvdata(hdev);
123 
124 	return sprintf(buf, "%d\n", nd->sensor_logical_width);
125 }
126 
127 static DEVICE_ATTR(sensor_logical_width, S_IRUGO, show_log_width, NULL);
128 
129 static ssize_t show_log_height(struct device *dev,
130 			       struct device_attribute *attr,
131 			       char *buf)
132 {
133 	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
134 	struct ntrig_data *nd = hid_get_drvdata(hdev);
135 
136 	return sprintf(buf, "%d\n", nd->sensor_logical_height);
137 }
138 
139 static DEVICE_ATTR(sensor_logical_height, S_IRUGO, show_log_height, NULL);
140 
141 static ssize_t show_min_width(struct device *dev,
142 			      struct device_attribute *attr,
143 			      char *buf)
144 {
145 	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
146 	struct ntrig_data *nd = hid_get_drvdata(hdev);
147 
148 	return sprintf(buf, "%d\n", nd->min_width *
149 				    nd->sensor_physical_width /
150 				    nd->sensor_logical_width);
151 }
152 
153 static ssize_t set_min_width(struct device *dev,
154 			     struct device_attribute *attr,
155 			     const char *buf, size_t count)
156 {
157 	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
158 	struct ntrig_data *nd = hid_get_drvdata(hdev);
159 
160 	unsigned long val;
161 
162 	if (strict_strtoul(buf, 0, &val))
163 		return -EINVAL;
164 
165 	if (val > nd->sensor_physical_width)
166 		return -EINVAL;
167 
168 	nd->min_width = val * nd->sensor_logical_width /
169 			      nd->sensor_physical_width;
170 
171 	return count;
172 }
173 
174 static DEVICE_ATTR(min_width, S_IWUSR | S_IRUGO, show_min_width, set_min_width);
175 
176 static ssize_t show_min_height(struct device *dev,
177 			       struct device_attribute *attr,
178 			       char *buf)
179 {
180 	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
181 	struct ntrig_data *nd = hid_get_drvdata(hdev);
182 
183 	return sprintf(buf, "%d\n", nd->min_height *
184 				    nd->sensor_physical_height /
185 				    nd->sensor_logical_height);
186 }
187 
188 static ssize_t set_min_height(struct device *dev,
189 			      struct device_attribute *attr,
190 			      const char *buf, size_t count)
191 {
192 	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
193 	struct ntrig_data *nd = hid_get_drvdata(hdev);
194 
195 	unsigned long val;
196 
197 	if (strict_strtoul(buf, 0, &val))
198 		return -EINVAL;
199 
200 	if (val > nd->sensor_physical_height)
201 		return -EINVAL;
202 
203 	nd->min_height = val * nd->sensor_logical_height /
204 			       nd->sensor_physical_height;
205 
206 	return count;
207 }
208 
209 static DEVICE_ATTR(min_height, S_IWUSR | S_IRUGO, show_min_height,
210 		   set_min_height);
211 
212 static ssize_t show_activate_slack(struct device *dev,
213 				   struct device_attribute *attr,
214 				   char *buf)
215 {
216 	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
217 	struct ntrig_data *nd = hid_get_drvdata(hdev);
218 
219 	return sprintf(buf, "%d\n", nd->activate_slack);
220 }
221 
222 static ssize_t set_activate_slack(struct device *dev,
223 				  struct device_attribute *attr,
224 				  const char *buf, size_t count)
225 {
226 	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
227 	struct ntrig_data *nd = hid_get_drvdata(hdev);
228 
229 	unsigned long val;
230 
231 	if (strict_strtoul(buf, 0, &val))
232 		return -EINVAL;
233 
234 	if (val > 0x7f)
235 		return -EINVAL;
236 
237 	nd->activate_slack = val;
238 
239 	return count;
240 }
241 
242 static DEVICE_ATTR(activate_slack, S_IWUSR | S_IRUGO, show_activate_slack,
243 		   set_activate_slack);
244 
245 static ssize_t show_activation_width(struct device *dev,
246 				     struct device_attribute *attr,
247 				     char *buf)
248 {
249 	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
250 	struct ntrig_data *nd = hid_get_drvdata(hdev);
251 
252 	return sprintf(buf, "%d\n", nd->activation_width *
253 				    nd->sensor_physical_width /
254 				    nd->sensor_logical_width);
255 }
256 
257 static ssize_t set_activation_width(struct device *dev,
258 				    struct device_attribute *attr,
259 				    const char *buf, size_t count)
260 {
261 	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
262 	struct ntrig_data *nd = hid_get_drvdata(hdev);
263 
264 	unsigned long val;
265 
266 	if (strict_strtoul(buf, 0, &val))
267 		return -EINVAL;
268 
269 	if (val > nd->sensor_physical_width)
270 		return -EINVAL;
271 
272 	nd->activation_width = val * nd->sensor_logical_width /
273 				     nd->sensor_physical_width;
274 
275 	return count;
276 }
277 
278 static DEVICE_ATTR(activation_width, S_IWUSR | S_IRUGO, show_activation_width,
279 		   set_activation_width);
280 
281 static ssize_t show_activation_height(struct device *dev,
282 				      struct device_attribute *attr,
283 				      char *buf)
284 {
285 	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
286 	struct ntrig_data *nd = hid_get_drvdata(hdev);
287 
288 	return sprintf(buf, "%d\n", nd->activation_height *
289 				    nd->sensor_physical_height /
290 				    nd->sensor_logical_height);
291 }
292 
293 static ssize_t set_activation_height(struct device *dev,
294 				     struct device_attribute *attr,
295 				     const char *buf, size_t count)
296 {
297 	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
298 	struct ntrig_data *nd = hid_get_drvdata(hdev);
299 
300 	unsigned long val;
301 
302 	if (strict_strtoul(buf, 0, &val))
303 		return -EINVAL;
304 
305 	if (val > nd->sensor_physical_height)
306 		return -EINVAL;
307 
308 	nd->activation_height = val * nd->sensor_logical_height /
309 				      nd->sensor_physical_height;
310 
311 	return count;
312 }
313 
314 static DEVICE_ATTR(activation_height, S_IWUSR | S_IRUGO,
315 		   show_activation_height, set_activation_height);
316 
317 static ssize_t show_deactivate_slack(struct device *dev,
318 				     struct device_attribute *attr,
319 				     char *buf)
320 {
321 	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
322 	struct ntrig_data *nd = hid_get_drvdata(hdev);
323 
324 	return sprintf(buf, "%d\n", -nd->deactivate_slack);
325 }
326 
327 static ssize_t set_deactivate_slack(struct device *dev,
328 				    struct device_attribute *attr,
329 				    const char *buf, size_t count)
330 {
331 	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
332 	struct ntrig_data *nd = hid_get_drvdata(hdev);
333 
334 	unsigned long val;
335 
336 	if (strict_strtoul(buf, 0, &val))
337 		return -EINVAL;
338 
339 	/*
340 	 * No more than 8 terminal frames have been observed so far
341 	 * and higher slack is highly likely to leave the single
342 	 * touch emulation stuck down.
343 	 */
344 	if (val > 7)
345 		return -EINVAL;
346 
347 	nd->deactivate_slack = -val;
348 
349 	return count;
350 }
351 
352 static DEVICE_ATTR(deactivate_slack, S_IWUSR | S_IRUGO, show_deactivate_slack,
353 		   set_deactivate_slack);
354 
355 static struct attribute *sysfs_attrs[] = {
356 	&dev_attr_sensor_physical_width.attr,
357 	&dev_attr_sensor_physical_height.attr,
358 	&dev_attr_sensor_logical_width.attr,
359 	&dev_attr_sensor_logical_height.attr,
360 	&dev_attr_min_height.attr,
361 	&dev_attr_min_width.attr,
362 	&dev_attr_activate_slack.attr,
363 	&dev_attr_activation_width.attr,
364 	&dev_attr_activation_height.attr,
365 	&dev_attr_deactivate_slack.attr,
366 	NULL
367 };
368 
369 static struct attribute_group ntrig_attribute_group = {
370 	.attrs = sysfs_attrs
371 };
372 
373 /*
374  * this driver is aimed at two firmware versions in circulation:
375  *  - dual pen/finger single touch
376  *  - finger multitouch, pen not working
377  */
378 
379 static int ntrig_input_mapping(struct hid_device *hdev, struct hid_input *hi,
380 		struct hid_field *field, struct hid_usage *usage,
381 		unsigned long **bit, int *max)
382 {
383 	struct ntrig_data *nd = hid_get_drvdata(hdev);
384 
385 	/* No special mappings needed for the pen and single touch */
386 	if (field->physical)
387 		return 0;
388 
389 	switch (usage->hid & HID_USAGE_PAGE) {
390 	case HID_UP_GENDESK:
391 		switch (usage->hid) {
392 		case HID_GD_X:
393 			hid_map_usage(hi, usage, bit, max,
394 					EV_ABS, ABS_MT_POSITION_X);
395 			input_set_abs_params(hi->input, ABS_X,
396 					field->logical_minimum,
397 					field->logical_maximum, 0, 0);
398 
399 			if (!nd->sensor_logical_width) {
400 				nd->sensor_logical_width =
401 					field->logical_maximum -
402 					field->logical_minimum;
403 				nd->sensor_physical_width =
404 					field->physical_maximum -
405 					field->physical_minimum;
406 				nd->activation_width = activation_width *
407 					nd->sensor_logical_width /
408 					nd->sensor_physical_width;
409 				nd->min_width = min_width *
410 					nd->sensor_logical_width /
411 					nd->sensor_physical_width;
412 			}
413 			return 1;
414 		case HID_GD_Y:
415 			hid_map_usage(hi, usage, bit, max,
416 					EV_ABS, ABS_MT_POSITION_Y);
417 			input_set_abs_params(hi->input, ABS_Y,
418 					field->logical_minimum,
419 					field->logical_maximum, 0, 0);
420 
421 			if (!nd->sensor_logical_height) {
422 				nd->sensor_logical_height =
423 					field->logical_maximum -
424 					field->logical_minimum;
425 				nd->sensor_physical_height =
426 					field->physical_maximum -
427 					field->physical_minimum;
428 				nd->activation_height = activation_height *
429 					nd->sensor_logical_height /
430 					nd->sensor_physical_height;
431 				nd->min_height = min_height *
432 					nd->sensor_logical_height /
433 					nd->sensor_physical_height;
434 			}
435 			return 1;
436 		}
437 		return 0;
438 
439 	case HID_UP_DIGITIZER:
440 		switch (usage->hid) {
441 		/* we do not want to map these for now */
442 		case HID_DG_CONTACTID: /* Not trustworthy, squelch for now */
443 		case HID_DG_INPUTMODE:
444 		case HID_DG_DEVICEINDEX:
445 		case HID_DG_CONTACTMAX:
446 			return -1;
447 
448 		/* width/height mapped on TouchMajor/TouchMinor/Orientation */
449 		case HID_DG_WIDTH:
450 			hid_map_usage(hi, usage, bit, max,
451 					EV_ABS, ABS_MT_TOUCH_MAJOR);
452 			return 1;
453 		case HID_DG_HEIGHT:
454 			hid_map_usage(hi, usage, bit, max,
455 					EV_ABS, ABS_MT_TOUCH_MINOR);
456 			input_set_abs_params(hi->input, ABS_MT_ORIENTATION,
457 					0, 1, 0, 0);
458 			return 1;
459 		}
460 		return 0;
461 
462 	case 0xff000000:
463 		/* we do not want to map these: no input-oriented meaning */
464 		return -1;
465 	}
466 
467 	return 0;
468 }
469 
470 static int ntrig_input_mapped(struct hid_device *hdev, struct hid_input *hi,
471 		struct hid_field *field, struct hid_usage *usage,
472 		unsigned long **bit, int *max)
473 {
474 	/* No special mappings needed for the pen and single touch */
475 	if (field->physical)
476 		return 0;
477 
478 	if (usage->type == EV_KEY || usage->type == EV_REL
479 			|| usage->type == EV_ABS)
480 		clear_bit(usage->code, *bit);
481 
482 	return 0;
483 }
484 
485 /*
486  * this function is called upon all reports
487  * so that we can filter contact point information,
488  * decide whether we are in multi or single touch mode
489  * and call input_mt_sync after each point if necessary
490  */
491 static int ntrig_event (struct hid_device *hid, struct hid_field *field,
492 		                        struct hid_usage *usage, __s32 value)
493 {
494 	struct input_dev *input = field->hidinput->input;
495 	struct ntrig_data *nd = hid_get_drvdata(hid);
496 
497 	/* No special handling needed for the pen */
498 	if (field->application == HID_DG_PEN)
499 		return 0;
500 
501         if (hid->claimed & HID_CLAIMED_INPUT) {
502 		switch (usage->hid) {
503 		case 0xff000001:
504 			/* Tag indicating the start of a multitouch group */
505 			nd->reading_mt = 1;
506 			nd->first_contact_touch = 0;
507 			break;
508 		case HID_DG_TIPSWITCH:
509 			nd->tipswitch = value;
510 			/* Prevent emission of touch until validated */
511 			return 1;
512 		case HID_DG_CONFIDENCE:
513 			nd->confidence = value;
514 			break;
515 		case HID_GD_X:
516 			nd->x = value;
517 			/* Clear the contact footer */
518 			nd->mt_foot_count = 0;
519 			break;
520 		case HID_GD_Y:
521 			nd->y = value;
522 			break;
523 		case HID_DG_CONTACTID:
524 			nd->id = value;
525 			break;
526 		case HID_DG_WIDTH:
527 			nd->w = value;
528 			break;
529 		case HID_DG_HEIGHT:
530 			nd->h = value;
531 			/*
532 			 * when in single touch mode, this is the last
533 			 * report received in a finger event. We want
534 			 * to emit a normal (X, Y) position
535 			 */
536 			if (!nd->reading_mt) {
537 				/*
538 				 * TipSwitch indicates the presence of a
539 				 * finger in single touch mode.
540 				 */
541 				input_report_key(input, BTN_TOUCH,
542 						 nd->tipswitch);
543 				input_report_key(input, BTN_TOOL_DOUBLETAP,
544 						 nd->tipswitch);
545 				input_event(input, EV_ABS, ABS_X, nd->x);
546 				input_event(input, EV_ABS, ABS_Y, nd->y);
547 			}
548 			break;
549 		case 0xff000002:
550 			/*
551 			 * we receive this when the device is in multitouch
552 			 * mode. The first of the three values tagged with
553 			 * this usage tells if the contact point is real
554 			 * or a placeholder
555 			 */
556 
557 			/* Shouldn't get more than 4 footer packets, so skip */
558 			if (nd->mt_foot_count >= 4)
559 				break;
560 
561 			nd->mt_footer[nd->mt_foot_count++] = value;
562 
563 			/* if the footer isn't complete break */
564 			if (nd->mt_foot_count != 4)
565 				break;
566 
567 			/* Pen activity signal. */
568 			if (nd->mt_footer[2]) {
569 				/*
570 				 * When the pen deactivates touch, we see a
571 				 * bogus frame with ContactCount > 0.
572 				 * We can
573 				 * save a bit of work by ensuring act_state < 0
574 				 * even if deactivation slack is turned off.
575 				 */
576 				nd->act_state = deactivate_slack - 1;
577 				nd->confidence = 0;
578 				break;
579 			}
580 
581 			/*
582 			 * The first footer value indicates the presence of a
583 			 * finger.
584 			 */
585 			if (nd->mt_footer[0]) {
586 				/*
587 				 * We do not want to process contacts under
588 				 * the size threshold, but do not want to
589 				 * ignore them for activation state
590 				 */
591 				if (nd->w < nd->min_width ||
592 				    nd->h < nd->min_height)
593 					nd->confidence = 0;
594 			} else
595 				break;
596 
597 			if (nd->act_state > 0) {
598 				/*
599 				 * Contact meets the activation size threshold
600 				 */
601 				if (nd->w >= nd->activation_width &&
602 				    nd->h >= nd->activation_height) {
603 					if (nd->id)
604 						/*
605 						 * first contact, activate now
606 						 */
607 						nd->act_state = 0;
608 					else {
609 						/*
610 						 * avoid corrupting this frame
611 						 * but ensure next frame will
612 						 * be active
613 						 */
614 						nd->act_state = 1;
615 						break;
616 					}
617 				} else
618 					/*
619 					 * Defer adjusting the activation state
620 					 * until the end of the frame.
621 					 */
622 					break;
623 			}
624 
625 			/* Discarding this contact */
626 			if (!nd->confidence)
627 				break;
628 
629 			/* emit a normal (X, Y) for the first point only */
630 			if (nd->id == 0) {
631 				/*
632 				 * TipSwitch is superfluous in multitouch
633 				 * mode.  The footer events tell us
634 				 * if there is a finger on the screen or
635 				 * not.
636 				 */
637 				nd->first_contact_touch = nd->confidence;
638 				input_event(input, EV_ABS, ABS_X, nd->x);
639 				input_event(input, EV_ABS, ABS_Y, nd->y);
640 			}
641 
642 			/* Emit MT events */
643 			input_event(input, EV_ABS, ABS_MT_POSITION_X, nd->x);
644 			input_event(input, EV_ABS, ABS_MT_POSITION_Y, nd->y);
645 
646 			/*
647 			 * Translate from height and width to size
648 			 * and orientation.
649 			 */
650 			if (nd->w > nd->h) {
651 				input_event(input, EV_ABS,
652 						ABS_MT_ORIENTATION, 1);
653 				input_event(input, EV_ABS,
654 						ABS_MT_TOUCH_MAJOR, nd->w);
655 				input_event(input, EV_ABS,
656 						ABS_MT_TOUCH_MINOR, nd->h);
657 			} else {
658 				input_event(input, EV_ABS,
659 						ABS_MT_ORIENTATION, 0);
660 				input_event(input, EV_ABS,
661 						ABS_MT_TOUCH_MAJOR, nd->h);
662 				input_event(input, EV_ABS,
663 						ABS_MT_TOUCH_MINOR, nd->w);
664 			}
665 			input_mt_sync(field->hidinput->input);
666 			break;
667 
668 		case HID_DG_CONTACTCOUNT: /* End of a multitouch group */
669 			if (!nd->reading_mt) /* Just to be sure */
670 				break;
671 
672 			nd->reading_mt = 0;
673 
674 
675 			/*
676 			 * Activation state machine logic:
677 			 *
678 			 * Fundamental states:
679 			 *	state >  0: Inactive
680 			 *	state <= 0: Active
681 			 *	state <  -deactivate_slack:
682 			 *		 Pen termination of touch
683 			 *
684 			 * Specific values of interest
685 			 *	state == activate_slack
686 			 *		 no valid input since the last reset
687 			 *
688 			 *	state == 0
689 			 *		 general operational state
690 			 *
691 			 *	state == -deactivate_slack
692 			 *		 read sufficient empty frames to accept
693 			 *		 the end of input and reset
694 			 */
695 
696 			if (nd->act_state > 0) { /* Currently inactive */
697 				if (value)
698 					/*
699 					 * Consider each live contact as
700 					 * evidence of intentional activity.
701 					 */
702 					nd->act_state = (nd->act_state > value)
703 							? nd->act_state - value
704 							: 0;
705 				else
706 					/*
707 					 * Empty frame before we hit the
708 					 * activity threshold, reset.
709 					 */
710 					nd->act_state = nd->activate_slack;
711 
712 				/*
713 				 * Entered this block inactive and no
714 				 * coordinates sent this frame, so hold off
715 				 * on button state.
716 				 */
717 				break;
718 			} else { /* Currently active */
719 				if (value && nd->act_state >=
720 					     nd->deactivate_slack)
721 					/*
722 					 * Live point: clear accumulated
723 					 * deactivation count.
724 					 */
725 					nd->act_state = 0;
726 				else if (nd->act_state <= nd->deactivate_slack)
727 					/*
728 					 * We've consumed the deactivation
729 					 * slack, time to deactivate and reset.
730 					 */
731 					nd->act_state =
732 						nd->activate_slack;
733 				else { /* Move towards deactivation */
734 					nd->act_state--;
735 					break;
736 				}
737 			}
738 
739 			if (nd->first_contact_touch && nd->act_state <= 0) {
740 				/*
741 				 * Check to see if we're ready to start
742 				 * emitting touch events.
743 				 *
744 				 * Note: activation slack will decrease over
745 				 * the course of the frame, and it will be
746 				 * inconsistent from the start to the end of
747 				 * the frame.  However if the frame starts
748 				 * with slack, first_contact_touch will still
749 				 * be 0 and we will not get to this point.
750 				 */
751 				input_report_key(input, BTN_TOOL_DOUBLETAP, 1);
752 				input_report_key(input, BTN_TOUCH, 1);
753 			} else {
754 				input_report_key(input, BTN_TOOL_DOUBLETAP, 0);
755 				input_report_key(input, BTN_TOUCH, 0);
756 			}
757 			break;
758 
759 		default:
760 			/* fall-back to the generic hidinput handling */
761 			return 0;
762 		}
763 	}
764 
765 	/* we have handled the hidinput part, now remains hiddev */
766 	if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_hid_event)
767 		hid->hiddev_hid_event(hid, field, usage, value);
768 
769 	return 1;
770 }
771 
772 static int ntrig_probe(struct hid_device *hdev, const struct hid_device_id *id)
773 {
774 	int ret;
775 	struct ntrig_data *nd;
776 	struct hid_input *hidinput;
777 	struct input_dev *input;
778 	struct hid_report *report;
779 
780 	if (id->driver_data)
781 		hdev->quirks |= HID_QUIRK_MULTI_INPUT;
782 
783 	nd = kmalloc(sizeof(struct ntrig_data), GFP_KERNEL);
784 	if (!nd) {
785 		dev_err(&hdev->dev, "cannot allocate N-Trig data\n");
786 		return -ENOMEM;
787 	}
788 
789 	nd->reading_mt = 0;
790 	nd->min_width = 0;
791 	nd->min_height = 0;
792 	nd->activate_slack = activate_slack;
793 	nd->act_state = activate_slack;
794 	nd->deactivate_slack = -deactivate_slack;
795 	nd->sensor_logical_width = 0;
796 	nd->sensor_logical_height = 0;
797 	nd->sensor_physical_width = 0;
798 	nd->sensor_physical_height = 0;
799 
800 	hid_set_drvdata(hdev, nd);
801 
802 	ret = hid_parse(hdev);
803 	if (ret) {
804 		dev_err(&hdev->dev, "parse failed\n");
805 		goto err_free;
806 	}
807 
808 	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT & ~HID_CONNECT_FF);
809 	if (ret) {
810 		dev_err(&hdev->dev, "hw start failed\n");
811 		goto err_free;
812 	}
813 
814 
815 	list_for_each_entry(hidinput, &hdev->inputs, list) {
816 		if (hidinput->report->maxfield < 1)
817 			continue;
818 
819 		input = hidinput->input;
820 		switch (hidinput->report->field[0]->application) {
821 		case HID_DG_PEN:
822 			input->name = "N-Trig Pen";
823 			break;
824 		case HID_DG_TOUCHSCREEN:
825 			/* These keys are redundant for fingers, clear them
826 			 * to prevent incorrect identification */
827 			__clear_bit(BTN_TOOL_PEN, input->keybit);
828 			__clear_bit(BTN_TOOL_FINGER, input->keybit);
829 			__clear_bit(BTN_0, input->keybit);
830 			__set_bit(BTN_TOOL_DOUBLETAP, input->keybit);
831 			/*
832 			 * The physical touchscreen (single touch)
833 			 * input has a value for physical, whereas
834 			 * the multitouch only has logical input
835 			 * fields.
836 			 */
837 			input->name =
838 				(hidinput->report->field[0]
839 				 ->physical) ?
840 				"N-Trig Touchscreen" :
841 				"N-Trig MultiTouch";
842 			break;
843 		}
844 	}
845 
846 	/* This is needed for devices with more recent firmware versions */
847 	report = hdev->report_enum[HID_FEATURE_REPORT].report_id_hash[0x0a];
848 	if (report)
849 		usbhid_submit_report(hdev, report, USB_DIR_OUT);
850 
851 	ret = sysfs_create_group(&hdev->dev.kobj,
852 			&ntrig_attribute_group);
853 
854 	return 0;
855 err_free:
856 	kfree(nd);
857 	return ret;
858 }
859 
860 static void ntrig_remove(struct hid_device *hdev)
861 {
862 	sysfs_remove_group(&hdev->dev.kobj,
863 			&ntrig_attribute_group);
864 	hid_hw_stop(hdev);
865 	kfree(hid_get_drvdata(hdev));
866 }
867 
868 static const struct hid_device_id ntrig_devices[] = {
869 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN),
870 		.driver_data = NTRIG_DUPLICATE_USAGES },
871 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_1),
872 		.driver_data = NTRIG_DUPLICATE_USAGES },
873 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_2),
874 		.driver_data = NTRIG_DUPLICATE_USAGES },
875 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_3),
876 		.driver_data = NTRIG_DUPLICATE_USAGES },
877 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_4),
878 		.driver_data = NTRIG_DUPLICATE_USAGES },
879 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_5),
880 		.driver_data = NTRIG_DUPLICATE_USAGES },
881 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_6),
882 		.driver_data = NTRIG_DUPLICATE_USAGES },
883 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_7),
884 		.driver_data = NTRIG_DUPLICATE_USAGES },
885 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_8),
886 		.driver_data = NTRIG_DUPLICATE_USAGES },
887 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_9),
888 		.driver_data = NTRIG_DUPLICATE_USAGES },
889 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_10),
890 		.driver_data = NTRIG_DUPLICATE_USAGES },
891 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_11),
892 		.driver_data = NTRIG_DUPLICATE_USAGES },
893 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_12),
894 		.driver_data = NTRIG_DUPLICATE_USAGES },
895 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_13),
896 		.driver_data = NTRIG_DUPLICATE_USAGES },
897 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_14),
898 		.driver_data = NTRIG_DUPLICATE_USAGES },
899 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_15),
900 		.driver_data = NTRIG_DUPLICATE_USAGES },
901 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_16),
902 		.driver_data = NTRIG_DUPLICATE_USAGES },
903 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_17),
904 		.driver_data = NTRIG_DUPLICATE_USAGES },
905 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_18),
906 		.driver_data = NTRIG_DUPLICATE_USAGES },
907 	{ }
908 };
909 MODULE_DEVICE_TABLE(hid, ntrig_devices);
910 
911 static const struct hid_usage_id ntrig_grabbed_usages[] = {
912 	{ HID_ANY_ID, HID_ANY_ID, HID_ANY_ID },
913 	{ HID_ANY_ID - 1, HID_ANY_ID - 1, HID_ANY_ID - 1 }
914 };
915 
916 static struct hid_driver ntrig_driver = {
917 	.name = "ntrig",
918 	.id_table = ntrig_devices,
919 	.probe = ntrig_probe,
920 	.remove = ntrig_remove,
921 	.input_mapping = ntrig_input_mapping,
922 	.input_mapped = ntrig_input_mapped,
923 	.usage_table = ntrig_grabbed_usages,
924 	.event = ntrig_event,
925 };
926 
927 static int __init ntrig_init(void)
928 {
929 	return hid_register_driver(&ntrig_driver);
930 }
931 
932 static void __exit ntrig_exit(void)
933 {
934 	hid_unregister_driver(&ntrig_driver);
935 }
936 
937 module_init(ntrig_init);
938 module_exit(ntrig_exit);
939 MODULE_LICENSE("GPL");
940