xref: /linux/drivers/hid/hid-ntrig.c (revision 856e7c4b619af622d56b3b454f7bec32a170ac99)
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 /*
94  * This function converts the 4 byte raw firmware code into
95  * a string containing 5 comma separated numbers.
96  */
97 static int ntrig_version_string(unsigned char *raw, char *buf)
98 {
99 	__u8 a =  (raw[1] & 0x0e) >> 1;
100 	__u8 b =  (raw[0] & 0x3c) >> 2;
101 	__u8 c = ((raw[0] & 0x03) << 3) | ((raw[3] & 0xe0) >> 5);
102 	__u8 d = ((raw[3] & 0x07) << 3) | ((raw[2] & 0xe0) >> 5);
103 	__u8 e =   raw[2] & 0x07;
104 
105 	/*
106 	 * As yet unmapped bits:
107 	 * 0b11000000 0b11110001 0b00011000 0b00011000
108 	 */
109 
110 	return sprintf(buf, "%u.%u.%u.%u.%u", a, b, c, d, e);
111 }
112 
113 static inline int ntrig_get_mode(struct hid_device *hdev)
114 {
115 	struct hid_report *report = hdev->report_enum[HID_FEATURE_REPORT].
116 				    report_id_hash[0x0d];
117 
118 	if (!report || report->maxfield < 1 ||
119 	    report->field[0]->report_count < 1)
120 		return -EINVAL;
121 
122 	hid_hw_request(hdev, report, HID_REQ_GET_REPORT);
123 	hid_hw_wait(hdev);
124 	return (int)report->field[0]->value[0];
125 }
126 
127 static inline void ntrig_set_mode(struct hid_device *hdev, const int mode)
128 {
129 	struct hid_report *report;
130 	__u8 mode_commands[4] = { 0xe, 0xf, 0x1b, 0x10 };
131 
132 	if (mode < 0 || mode > 3)
133 		return;
134 
135 	report = hdev->report_enum[HID_FEATURE_REPORT].
136 		 report_id_hash[mode_commands[mode]];
137 
138 	if (!report)
139 		return;
140 
141 	hid_hw_request(hdev, report, HID_REQ_GET_REPORT);
142 }
143 
144 static void ntrig_report_version(struct hid_device *hdev)
145 {
146 	int ret;
147 	char buf[20];
148 	struct usb_device *usb_dev = hid_to_usb_dev(hdev);
149 	unsigned char *data = kmalloc(8, GFP_KERNEL);
150 
151 	if (!data)
152 		goto err_free;
153 
154 	ret = usb_control_msg(usb_dev, usb_rcvctrlpipe(usb_dev, 0),
155 			      USB_REQ_CLEAR_FEATURE,
156 			      USB_TYPE_CLASS | USB_RECIP_INTERFACE |
157 			      USB_DIR_IN,
158 			      0x30c, 1, data, 8,
159 			      USB_CTRL_SET_TIMEOUT);
160 
161 	if (ret == 8) {
162 		ret = ntrig_version_string(&data[2], buf);
163 
164 		hid_info(hdev, "Firmware version: %s (%02x%02x %02x%02x)\n",
165 			 buf, data[2], data[3], data[4], data[5]);
166 	}
167 
168 err_free:
169 	kfree(data);
170 }
171 
172 static ssize_t show_phys_width(struct device *dev,
173 			       struct device_attribute *attr,
174 			       char *buf)
175 {
176 	struct hid_device *hdev = to_hid_device(dev);
177 	struct ntrig_data *nd = hid_get_drvdata(hdev);
178 
179 	return sprintf(buf, "%d\n", nd->sensor_physical_width);
180 }
181 
182 static DEVICE_ATTR(sensor_physical_width, S_IRUGO, show_phys_width, NULL);
183 
184 static ssize_t show_phys_height(struct device *dev,
185 				struct device_attribute *attr,
186 				char *buf)
187 {
188 	struct hid_device *hdev = to_hid_device(dev);
189 	struct ntrig_data *nd = hid_get_drvdata(hdev);
190 
191 	return sprintf(buf, "%d\n", nd->sensor_physical_height);
192 }
193 
194 static DEVICE_ATTR(sensor_physical_height, S_IRUGO, show_phys_height, NULL);
195 
196 static ssize_t show_log_width(struct device *dev,
197 			      struct device_attribute *attr,
198 			      char *buf)
199 {
200 	struct hid_device *hdev = to_hid_device(dev);
201 	struct ntrig_data *nd = hid_get_drvdata(hdev);
202 
203 	return sprintf(buf, "%d\n", nd->sensor_logical_width);
204 }
205 
206 static DEVICE_ATTR(sensor_logical_width, S_IRUGO, show_log_width, NULL);
207 
208 static ssize_t show_log_height(struct device *dev,
209 			       struct device_attribute *attr,
210 			       char *buf)
211 {
212 	struct hid_device *hdev = to_hid_device(dev);
213 	struct ntrig_data *nd = hid_get_drvdata(hdev);
214 
215 	return sprintf(buf, "%d\n", nd->sensor_logical_height);
216 }
217 
218 static DEVICE_ATTR(sensor_logical_height, S_IRUGO, show_log_height, NULL);
219 
220 static ssize_t show_min_width(struct device *dev,
221 			      struct device_attribute *attr,
222 			      char *buf)
223 {
224 	struct hid_device *hdev = to_hid_device(dev);
225 	struct ntrig_data *nd = hid_get_drvdata(hdev);
226 
227 	return sprintf(buf, "%d\n", nd->min_width *
228 				    nd->sensor_physical_width /
229 				    nd->sensor_logical_width);
230 }
231 
232 static ssize_t set_min_width(struct device *dev,
233 			     struct device_attribute *attr,
234 			     const char *buf, size_t count)
235 {
236 	struct hid_device *hdev = to_hid_device(dev);
237 	struct ntrig_data *nd = hid_get_drvdata(hdev);
238 
239 	unsigned long val;
240 
241 	if (kstrtoul(buf, 0, &val))
242 		return -EINVAL;
243 
244 	if (val > nd->sensor_physical_width)
245 		return -EINVAL;
246 
247 	nd->min_width = val * nd->sensor_logical_width /
248 			      nd->sensor_physical_width;
249 
250 	return count;
251 }
252 
253 static DEVICE_ATTR(min_width, S_IWUSR | S_IRUGO, show_min_width, set_min_width);
254 
255 static ssize_t show_min_height(struct device *dev,
256 			       struct device_attribute *attr,
257 			       char *buf)
258 {
259 	struct hid_device *hdev = to_hid_device(dev);
260 	struct ntrig_data *nd = hid_get_drvdata(hdev);
261 
262 	return sprintf(buf, "%d\n", nd->min_height *
263 				    nd->sensor_physical_height /
264 				    nd->sensor_logical_height);
265 }
266 
267 static ssize_t set_min_height(struct device *dev,
268 			      struct device_attribute *attr,
269 			      const char *buf, size_t count)
270 {
271 	struct hid_device *hdev = to_hid_device(dev);
272 	struct ntrig_data *nd = hid_get_drvdata(hdev);
273 
274 	unsigned long val;
275 
276 	if (kstrtoul(buf, 0, &val))
277 		return -EINVAL;
278 
279 	if (val > nd->sensor_physical_height)
280 		return -EINVAL;
281 
282 	nd->min_height = val * nd->sensor_logical_height /
283 			       nd->sensor_physical_height;
284 
285 	return count;
286 }
287 
288 static DEVICE_ATTR(min_height, S_IWUSR | S_IRUGO, show_min_height,
289 		   set_min_height);
290 
291 static ssize_t show_activate_slack(struct device *dev,
292 				   struct device_attribute *attr,
293 				   char *buf)
294 {
295 	struct hid_device *hdev = to_hid_device(dev);
296 	struct ntrig_data *nd = hid_get_drvdata(hdev);
297 
298 	return sprintf(buf, "%d\n", nd->activate_slack);
299 }
300 
301 static ssize_t set_activate_slack(struct device *dev,
302 				  struct device_attribute *attr,
303 				  const char *buf, size_t count)
304 {
305 	struct hid_device *hdev = to_hid_device(dev);
306 	struct ntrig_data *nd = hid_get_drvdata(hdev);
307 
308 	unsigned long val;
309 
310 	if (kstrtoul(buf, 0, &val))
311 		return -EINVAL;
312 
313 	if (val > 0x7f)
314 		return -EINVAL;
315 
316 	nd->activate_slack = val;
317 
318 	return count;
319 }
320 
321 static DEVICE_ATTR(activate_slack, S_IWUSR | S_IRUGO, show_activate_slack,
322 		   set_activate_slack);
323 
324 static ssize_t show_activation_width(struct device *dev,
325 				     struct device_attribute *attr,
326 				     char *buf)
327 {
328 	struct hid_device *hdev = to_hid_device(dev);
329 	struct ntrig_data *nd = hid_get_drvdata(hdev);
330 
331 	return sprintf(buf, "%d\n", nd->activation_width *
332 				    nd->sensor_physical_width /
333 				    nd->sensor_logical_width);
334 }
335 
336 static ssize_t set_activation_width(struct device *dev,
337 				    struct device_attribute *attr,
338 				    const char *buf, size_t count)
339 {
340 	struct hid_device *hdev = to_hid_device(dev);
341 	struct ntrig_data *nd = hid_get_drvdata(hdev);
342 
343 	unsigned long val;
344 
345 	if (kstrtoul(buf, 0, &val))
346 		return -EINVAL;
347 
348 	if (val > nd->sensor_physical_width)
349 		return -EINVAL;
350 
351 	nd->activation_width = val * nd->sensor_logical_width /
352 				     nd->sensor_physical_width;
353 
354 	return count;
355 }
356 
357 static DEVICE_ATTR(activation_width, S_IWUSR | S_IRUGO, show_activation_width,
358 		   set_activation_width);
359 
360 static ssize_t show_activation_height(struct device *dev,
361 				      struct device_attribute *attr,
362 				      char *buf)
363 {
364 	struct hid_device *hdev = to_hid_device(dev);
365 	struct ntrig_data *nd = hid_get_drvdata(hdev);
366 
367 	return sprintf(buf, "%d\n", nd->activation_height *
368 				    nd->sensor_physical_height /
369 				    nd->sensor_logical_height);
370 }
371 
372 static ssize_t set_activation_height(struct device *dev,
373 				     struct device_attribute *attr,
374 				     const char *buf, size_t count)
375 {
376 	struct hid_device *hdev = to_hid_device(dev);
377 	struct ntrig_data *nd = hid_get_drvdata(hdev);
378 
379 	unsigned long val;
380 
381 	if (kstrtoul(buf, 0, &val))
382 		return -EINVAL;
383 
384 	if (val > nd->sensor_physical_height)
385 		return -EINVAL;
386 
387 	nd->activation_height = val * nd->sensor_logical_height /
388 				      nd->sensor_physical_height;
389 
390 	return count;
391 }
392 
393 static DEVICE_ATTR(activation_height, S_IWUSR | S_IRUGO,
394 		   show_activation_height, set_activation_height);
395 
396 static ssize_t show_deactivate_slack(struct device *dev,
397 				     struct device_attribute *attr,
398 				     char *buf)
399 {
400 	struct hid_device *hdev = to_hid_device(dev);
401 	struct ntrig_data *nd = hid_get_drvdata(hdev);
402 
403 	return sprintf(buf, "%d\n", -nd->deactivate_slack);
404 }
405 
406 static ssize_t set_deactivate_slack(struct device *dev,
407 				    struct device_attribute *attr,
408 				    const char *buf, size_t count)
409 {
410 	struct hid_device *hdev = to_hid_device(dev);
411 	struct ntrig_data *nd = hid_get_drvdata(hdev);
412 
413 	unsigned long val;
414 
415 	if (kstrtoul(buf, 0, &val))
416 		return -EINVAL;
417 
418 	/*
419 	 * No more than 8 terminal frames have been observed so far
420 	 * and higher slack is highly likely to leave the single
421 	 * touch emulation stuck down.
422 	 */
423 	if (val > 7)
424 		return -EINVAL;
425 
426 	nd->deactivate_slack = -val;
427 
428 	return count;
429 }
430 
431 static DEVICE_ATTR(deactivate_slack, S_IWUSR | S_IRUGO, show_deactivate_slack,
432 		   set_deactivate_slack);
433 
434 static struct attribute *sysfs_attrs[] = {
435 	&dev_attr_sensor_physical_width.attr,
436 	&dev_attr_sensor_physical_height.attr,
437 	&dev_attr_sensor_logical_width.attr,
438 	&dev_attr_sensor_logical_height.attr,
439 	&dev_attr_min_height.attr,
440 	&dev_attr_min_width.attr,
441 	&dev_attr_activate_slack.attr,
442 	&dev_attr_activation_width.attr,
443 	&dev_attr_activation_height.attr,
444 	&dev_attr_deactivate_slack.attr,
445 	NULL
446 };
447 
448 static const struct attribute_group ntrig_attribute_group = {
449 	.attrs = sysfs_attrs
450 };
451 
452 /*
453  * this driver is aimed at two firmware versions in circulation:
454  *  - dual pen/finger single touch
455  *  - finger multitouch, pen not working
456  */
457 
458 static int ntrig_input_mapping(struct hid_device *hdev, struct hid_input *hi,
459 			       struct hid_field *field, struct hid_usage *usage,
460 			       unsigned long **bit, int *max)
461 {
462 	struct ntrig_data *nd = hid_get_drvdata(hdev);
463 
464 	/* No special mappings needed for the pen and single touch */
465 	if (field->physical)
466 		return 0;
467 
468 	switch (usage->hid & HID_USAGE_PAGE) {
469 	case HID_UP_GENDESK:
470 		switch (usage->hid) {
471 		case HID_GD_X:
472 			hid_map_usage(hi, usage, bit, max,
473 					EV_ABS, ABS_MT_POSITION_X);
474 			input_set_abs_params(hi->input, ABS_X,
475 					field->logical_minimum,
476 					field->logical_maximum, 0, 0);
477 
478 			if (!nd->sensor_logical_width) {
479 				nd->sensor_logical_width =
480 					field->logical_maximum -
481 					field->logical_minimum;
482 				nd->sensor_physical_width =
483 					field->physical_maximum -
484 					field->physical_minimum;
485 				nd->activation_width = activation_width *
486 					nd->sensor_logical_width /
487 					nd->sensor_physical_width;
488 				nd->min_width = min_width *
489 					nd->sensor_logical_width /
490 					nd->sensor_physical_width;
491 			}
492 			return 1;
493 		case HID_GD_Y:
494 			hid_map_usage(hi, usage, bit, max,
495 					EV_ABS, ABS_MT_POSITION_Y);
496 			input_set_abs_params(hi->input, ABS_Y,
497 					field->logical_minimum,
498 					field->logical_maximum, 0, 0);
499 
500 			if (!nd->sensor_logical_height) {
501 				nd->sensor_logical_height =
502 					field->logical_maximum -
503 					field->logical_minimum;
504 				nd->sensor_physical_height =
505 					field->physical_maximum -
506 					field->physical_minimum;
507 				nd->activation_height = activation_height *
508 					nd->sensor_logical_height /
509 					nd->sensor_physical_height;
510 				nd->min_height = min_height *
511 					nd->sensor_logical_height /
512 					nd->sensor_physical_height;
513 			}
514 			return 1;
515 		}
516 		return 0;
517 
518 	case HID_UP_DIGITIZER:
519 		switch (usage->hid) {
520 		/* we do not want to map these for now */
521 		case HID_DG_CONTACTID: /* Not trustworthy, squelch for now */
522 		case HID_DG_INPUTMODE:
523 		case HID_DG_DEVICEINDEX:
524 		case HID_DG_CONTACTMAX:
525 			return -1;
526 
527 		/* width/height mapped on TouchMajor/TouchMinor/Orientation */
528 		case HID_DG_WIDTH:
529 			hid_map_usage(hi, usage, bit, max,
530 				      EV_ABS, ABS_MT_TOUCH_MAJOR);
531 			return 1;
532 		case HID_DG_HEIGHT:
533 			hid_map_usage(hi, usage, bit, max,
534 				      EV_ABS, ABS_MT_TOUCH_MINOR);
535 			input_set_abs_params(hi->input, ABS_MT_ORIENTATION,
536 					     0, 1, 0, 0);
537 			return 1;
538 		}
539 		return 0;
540 
541 	case 0xff000000:
542 		/* we do not want to map these: no input-oriented meaning */
543 		return -1;
544 	}
545 
546 	return 0;
547 }
548 
549 static int ntrig_input_mapped(struct hid_device *hdev, struct hid_input *hi,
550 			      struct hid_field *field, struct hid_usage *usage,
551 			      unsigned long **bit, int *max)
552 {
553 	/* No special mappings needed for the pen and single touch */
554 	if (field->physical)
555 		return 0;
556 
557 	if (usage->type == EV_KEY || usage->type == EV_REL
558 			|| usage->type == EV_ABS)
559 		clear_bit(usage->code, *bit);
560 
561 	return 0;
562 }
563 
564 /*
565  * this function is called upon all reports
566  * so that we can filter contact point information,
567  * decide whether we are in multi or single touch mode
568  * and call input_mt_sync after each point if necessary
569  */
570 static int ntrig_event (struct hid_device *hid, struct hid_field *field,
571 			struct hid_usage *usage, __s32 value)
572 {
573 	struct ntrig_data *nd = hid_get_drvdata(hid);
574 	struct input_dev *input;
575 
576 	/* Skip processing if not a claimed input */
577 	if (!(hid->claimed & HID_CLAIMED_INPUT))
578 		goto not_claimed_input;
579 
580 	/* This function is being called before the structures are fully
581 	 * initialized */
582 	if(!(field->hidinput && field->hidinput->input))
583 		return -EINVAL;
584 
585 	input = field->hidinput->input;
586 
587 	/* No special handling needed for the pen */
588 	if (field->application == HID_DG_PEN)
589 		return 0;
590 
591 	switch (usage->hid) {
592 	case 0xff000001:
593 		/* Tag indicating the start of a multitouch group */
594 		nd->reading_mt = true;
595 		nd->first_contact_touch = false;
596 		break;
597 	case HID_DG_TIPSWITCH:
598 		nd->tipswitch = value;
599 		/* Prevent emission of touch until validated */
600 		return 1;
601 	case HID_DG_CONFIDENCE:
602 		nd->confidence = value;
603 		break;
604 	case HID_GD_X:
605 		nd->x = value;
606 		/* Clear the contact footer */
607 		nd->mt_foot_count = 0;
608 		break;
609 	case HID_GD_Y:
610 		nd->y = value;
611 		break;
612 	case HID_DG_CONTACTID:
613 		nd->id = value;
614 		break;
615 	case HID_DG_WIDTH:
616 		nd->w = value;
617 		break;
618 	case HID_DG_HEIGHT:
619 		nd->h = value;
620 		/*
621 		 * when in single touch mode, this is the last
622 		 * report received in a finger event. We want
623 		 * to emit a normal (X, Y) position
624 		 */
625 		if (!nd->reading_mt) {
626 			/*
627 			 * TipSwitch indicates the presence of a
628 			 * finger in single touch mode.
629 			 */
630 			input_report_key(input, BTN_TOUCH,
631 					 nd->tipswitch);
632 			input_report_key(input, BTN_TOOL_DOUBLETAP,
633 					 nd->tipswitch);
634 			input_event(input, EV_ABS, ABS_X, nd->x);
635 			input_event(input, EV_ABS, ABS_Y, nd->y);
636 		}
637 		break;
638 	case 0xff000002:
639 		/*
640 		 * we receive this when the device is in multitouch
641 		 * mode. The first of the three values tagged with
642 		 * this usage tells if the contact point is real
643 		 * or a placeholder
644 		 */
645 
646 		/* Shouldn't get more than 4 footer packets, so skip */
647 		if (nd->mt_foot_count >= 4)
648 			break;
649 
650 		nd->mt_footer[nd->mt_foot_count++] = value;
651 
652 		/* if the footer isn't complete break */
653 		if (nd->mt_foot_count != 4)
654 			break;
655 
656 		/* Pen activity signal. */
657 		if (nd->mt_footer[2]) {
658 			/*
659 			 * When the pen deactivates touch, we see a
660 			 * bogus frame with ContactCount > 0.
661 			 * We can
662 			 * save a bit of work by ensuring act_state < 0
663 			 * even if deactivation slack is turned off.
664 			 */
665 			nd->act_state = deactivate_slack - 1;
666 			nd->confidence = false;
667 			break;
668 		}
669 
670 		/*
671 		 * The first footer value indicates the presence of a
672 		 * finger.
673 		 */
674 		if (nd->mt_footer[0]) {
675 			/*
676 			 * We do not want to process contacts under
677 			 * the size threshold, but do not want to
678 			 * ignore them for activation state
679 			 */
680 			if (nd->w < nd->min_width ||
681 			    nd->h < nd->min_height)
682 				nd->confidence = false;
683 		} else
684 			break;
685 
686 		if (nd->act_state > 0) {
687 			/*
688 			 * Contact meets the activation size threshold
689 			 */
690 			if (nd->w >= nd->activation_width &&
691 			    nd->h >= nd->activation_height) {
692 				if (nd->id)
693 					/*
694 					 * first contact, activate now
695 					 */
696 					nd->act_state = 0;
697 				else {
698 					/*
699 					 * avoid corrupting this frame
700 					 * but ensure next frame will
701 					 * be active
702 					 */
703 					nd->act_state = 1;
704 					break;
705 				}
706 			} else
707 				/*
708 				 * Defer adjusting the activation state
709 				 * until the end of the frame.
710 				 */
711 				break;
712 		}
713 
714 		/* Discarding this contact */
715 		if (!nd->confidence)
716 			break;
717 
718 		/* emit a normal (X, Y) for the first point only */
719 		if (nd->id == 0) {
720 			/*
721 			 * TipSwitch is superfluous in multitouch
722 			 * mode.  The footer events tell us
723 			 * if there is a finger on the screen or
724 			 * not.
725 			 */
726 			nd->first_contact_touch = nd->confidence;
727 			input_event(input, EV_ABS, ABS_X, nd->x);
728 			input_event(input, EV_ABS, ABS_Y, nd->y);
729 		}
730 
731 		/* Emit MT events */
732 		input_event(input, EV_ABS, ABS_MT_POSITION_X, nd->x);
733 		input_event(input, EV_ABS, ABS_MT_POSITION_Y, nd->y);
734 
735 		/*
736 		 * Translate from height and width to size
737 		 * and orientation.
738 		 */
739 		if (nd->w > nd->h) {
740 			input_event(input, EV_ABS,
741 					ABS_MT_ORIENTATION, 1);
742 			input_event(input, EV_ABS,
743 					ABS_MT_TOUCH_MAJOR, nd->w);
744 			input_event(input, EV_ABS,
745 					ABS_MT_TOUCH_MINOR, nd->h);
746 		} else {
747 			input_event(input, EV_ABS,
748 					ABS_MT_ORIENTATION, 0);
749 			input_event(input, EV_ABS,
750 					ABS_MT_TOUCH_MAJOR, nd->h);
751 			input_event(input, EV_ABS,
752 					ABS_MT_TOUCH_MINOR, nd->w);
753 		}
754 		input_mt_sync(field->hidinput->input);
755 		break;
756 
757 	case HID_DG_CONTACTCOUNT: /* End of a multitouch group */
758 		if (!nd->reading_mt) /* Just to be sure */
759 			break;
760 
761 		nd->reading_mt = false;
762 
763 
764 		/*
765 		 * Activation state machine logic:
766 		 *
767 		 * Fundamental states:
768 		 *	state >  0: Inactive
769 		 *	state <= 0: Active
770 		 *	state <  -deactivate_slack:
771 		 *		 Pen termination of touch
772 		 *
773 		 * Specific values of interest
774 		 *	state == activate_slack
775 		 *		 no valid input since the last reset
776 		 *
777 		 *	state == 0
778 		 *		 general operational state
779 		 *
780 		 *	state == -deactivate_slack
781 		 *		 read sufficient empty frames to accept
782 		 *		 the end of input and reset
783 		 */
784 
785 		if (nd->act_state > 0) { /* Currently inactive */
786 			if (value)
787 				/*
788 				 * Consider each live contact as
789 				 * evidence of intentional activity.
790 				 */
791 				nd->act_state = (nd->act_state > value)
792 						? nd->act_state - value
793 						: 0;
794 			else
795 				/*
796 				 * Empty frame before we hit the
797 				 * activity threshold, reset.
798 				 */
799 				nd->act_state = nd->activate_slack;
800 
801 			/*
802 			 * Entered this block inactive and no
803 			 * coordinates sent this frame, so hold off
804 			 * on button state.
805 			 */
806 			break;
807 		} else { /* Currently active */
808 			if (value && nd->act_state >=
809 				     nd->deactivate_slack)
810 				/*
811 				 * Live point: clear accumulated
812 				 * deactivation count.
813 				 */
814 				nd->act_state = 0;
815 			else if (nd->act_state <= nd->deactivate_slack)
816 				/*
817 				 * We've consumed the deactivation
818 				 * slack, time to deactivate and reset.
819 				 */
820 				nd->act_state =
821 					nd->activate_slack;
822 			else { /* Move towards deactivation */
823 				nd->act_state--;
824 				break;
825 			}
826 		}
827 
828 		if (nd->first_contact_touch && nd->act_state <= 0) {
829 			/*
830 			 * Check to see if we're ready to start
831 			 * emitting touch events.
832 			 *
833 			 * Note: activation slack will decrease over
834 			 * the course of the frame, and it will be
835 			 * inconsistent from the start to the end of
836 			 * the frame.  However if the frame starts
837 			 * with slack, first_contact_touch will still
838 			 * be 0 and we will not get to this point.
839 			 */
840 			input_report_key(input, BTN_TOOL_DOUBLETAP, 1);
841 			input_report_key(input, BTN_TOUCH, 1);
842 		} else {
843 			input_report_key(input, BTN_TOOL_DOUBLETAP, 0);
844 			input_report_key(input, BTN_TOUCH, 0);
845 		}
846 		break;
847 
848 	default:
849 		/* fall-back to the generic hidinput handling */
850 		return 0;
851 	}
852 
853 not_claimed_input:
854 
855 	/* we have handled the hidinput part, now remains hiddev */
856 	if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_hid_event)
857 		hid->hiddev_hid_event(hid, field, usage, value);
858 
859 	return 1;
860 }
861 
862 static int ntrig_input_configured(struct hid_device *hid,
863 		struct hid_input *hidinput)
864 
865 {
866 	struct input_dev *input = hidinput->input;
867 
868 	if (hidinput->report->maxfield < 1)
869 		return 0;
870 
871 	switch (hidinput->report->field[0]->application) {
872 	case HID_DG_PEN:
873 		input->name = "N-Trig Pen";
874 		break;
875 	case HID_DG_TOUCHSCREEN:
876 		/* These keys are redundant for fingers, clear them
877 		 * to prevent incorrect identification */
878 		__clear_bit(BTN_TOOL_PEN, input->keybit);
879 		__clear_bit(BTN_TOOL_FINGER, input->keybit);
880 		__clear_bit(BTN_0, input->keybit);
881 		__set_bit(BTN_TOOL_DOUBLETAP, input->keybit);
882 		/*
883 		 * The physical touchscreen (single touch)
884 		 * input has a value for physical, whereas
885 		 * the multitouch only has logical input
886 		 * fields.
887 		 */
888 		input->name = (hidinput->report->field[0]->physical) ?
889 							"N-Trig Touchscreen" :
890 							"N-Trig MultiTouch";
891 		break;
892 	}
893 
894 	return 0;
895 }
896 
897 static int ntrig_probe(struct hid_device *hdev, const struct hid_device_id *id)
898 {
899 	int ret;
900 	struct ntrig_data *nd;
901 	struct hid_report *report;
902 
903 	if (id->driver_data)
904 		hdev->quirks |= HID_QUIRK_MULTI_INPUT
905 				| HID_QUIRK_NO_INIT_REPORTS;
906 
907 	nd = kmalloc(sizeof(struct ntrig_data), GFP_KERNEL);
908 	if (!nd) {
909 		hid_err(hdev, "cannot allocate N-Trig data\n");
910 		return -ENOMEM;
911 	}
912 
913 	nd->reading_mt = false;
914 	nd->min_width = 0;
915 	nd->min_height = 0;
916 	nd->activate_slack = activate_slack;
917 	nd->act_state = activate_slack;
918 	nd->deactivate_slack = -deactivate_slack;
919 	nd->sensor_logical_width = 1;
920 	nd->sensor_logical_height = 1;
921 	nd->sensor_physical_width = 1;
922 	nd->sensor_physical_height = 1;
923 
924 	hid_set_drvdata(hdev, nd);
925 
926 	ret = hid_parse(hdev);
927 	if (ret) {
928 		hid_err(hdev, "parse failed\n");
929 		goto err_free;
930 	}
931 
932 	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT & ~HID_CONNECT_FF);
933 	if (ret) {
934 		hid_err(hdev, "hw start failed\n");
935 		goto err_free;
936 	}
937 
938 	/* This is needed for devices with more recent firmware versions */
939 	report = hdev->report_enum[HID_FEATURE_REPORT].report_id_hash[0x0a];
940 	if (report) {
941 		/* Let the device settle to ensure the wakeup message gets
942 		 * through */
943 		hid_hw_wait(hdev);
944 		hid_hw_request(hdev, report, HID_REQ_GET_REPORT);
945 
946 		/*
947 		 * Sanity check: if the current mode is invalid reset it to
948 		 * something reasonable.
949 		 */
950 		if (ntrig_get_mode(hdev) >= 4)
951 			ntrig_set_mode(hdev, 3);
952 	}
953 
954 	ntrig_report_version(hdev);
955 
956 	ret = sysfs_create_group(&hdev->dev.kobj,
957 			&ntrig_attribute_group);
958 
959 	return 0;
960 err_free:
961 	kfree(nd);
962 	return ret;
963 }
964 
965 static void ntrig_remove(struct hid_device *hdev)
966 {
967 	sysfs_remove_group(&hdev->dev.kobj,
968 			   &ntrig_attribute_group);
969 	hid_hw_stop(hdev);
970 	kfree(hid_get_drvdata(hdev));
971 }
972 
973 static const struct hid_device_id ntrig_devices[] = {
974 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN),
975 		.driver_data = NTRIG_DUPLICATE_USAGES },
976 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_1),
977 		.driver_data = NTRIG_DUPLICATE_USAGES },
978 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_2),
979 		.driver_data = NTRIG_DUPLICATE_USAGES },
980 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_3),
981 		.driver_data = NTRIG_DUPLICATE_USAGES },
982 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_4),
983 		.driver_data = NTRIG_DUPLICATE_USAGES },
984 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_5),
985 		.driver_data = NTRIG_DUPLICATE_USAGES },
986 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_6),
987 		.driver_data = NTRIG_DUPLICATE_USAGES },
988 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_7),
989 		.driver_data = NTRIG_DUPLICATE_USAGES },
990 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_8),
991 		.driver_data = NTRIG_DUPLICATE_USAGES },
992 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_9),
993 		.driver_data = NTRIG_DUPLICATE_USAGES },
994 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_10),
995 		.driver_data = NTRIG_DUPLICATE_USAGES },
996 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_11),
997 		.driver_data = NTRIG_DUPLICATE_USAGES },
998 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_12),
999 		.driver_data = NTRIG_DUPLICATE_USAGES },
1000 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_13),
1001 		.driver_data = NTRIG_DUPLICATE_USAGES },
1002 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_14),
1003 		.driver_data = NTRIG_DUPLICATE_USAGES },
1004 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_15),
1005 		.driver_data = NTRIG_DUPLICATE_USAGES },
1006 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_16),
1007 		.driver_data = NTRIG_DUPLICATE_USAGES },
1008 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_17),
1009 		.driver_data = NTRIG_DUPLICATE_USAGES },
1010 	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_18),
1011 		.driver_data = NTRIG_DUPLICATE_USAGES },
1012 	{ }
1013 };
1014 MODULE_DEVICE_TABLE(hid, ntrig_devices);
1015 
1016 static const struct hid_usage_id ntrig_grabbed_usages[] = {
1017 	{ HID_ANY_ID, HID_ANY_ID, HID_ANY_ID },
1018 	{ HID_ANY_ID - 1, HID_ANY_ID - 1, HID_ANY_ID - 1 }
1019 };
1020 
1021 static struct hid_driver ntrig_driver = {
1022 	.name = "ntrig",
1023 	.id_table = ntrig_devices,
1024 	.probe = ntrig_probe,
1025 	.remove = ntrig_remove,
1026 	.input_mapping = ntrig_input_mapping,
1027 	.input_mapped = ntrig_input_mapped,
1028 	.input_configured = ntrig_input_configured,
1029 	.usage_table = ntrig_grabbed_usages,
1030 	.event = ntrig_event,
1031 };
1032 module_hid_driver(ntrig_driver);
1033 
1034 MODULE_LICENSE("GPL");
1035