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
27static unsigned int min_width;
28module_param(min_width, uint, 0644);
29MODULE_PARM_DESC(min_width, "Minimum touch contact width to accept.");
30
31static unsigned int min_height;
32module_param(min_height, uint, 0644);
33MODULE_PARM_DESC(min_height, "Minimum touch contact height to accept.");
34
35static unsigned int activate_slack = 1;
36module_param(activate_slack, uint, 0644);
37MODULE_PARM_DESC(activate_slack, "Number of touch frames to ignore at "
38		 "the start of touch input.");
39
40static unsigned int deactivate_slack = 4;
41module_param(deactivate_slack, uint, 0644);
42MODULE_PARM_DESC(deactivate_slack, "Number of empty frames to ignore before "
43		 "deactivating touch.");
44
45static unsigned int activation_width = 64;
46module_param(activation_width, uint, 0644);
47MODULE_PARM_DESC(activation_width, "Width threshold to immediately start "
48		 "processing touch events.");
49
50static unsigned int activation_height = 32;
51module_param(activation_height, uint, 0644);
52MODULE_PARM_DESC(activation_height, "Height threshold to immediately start "
53		 "processing touch events.");
54
55struct 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 */
97static 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
113static 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
127static 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
144static 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
168err_free:
169	kfree(data);
170}
171
172static ssize_t show_phys_width(struct device *dev,
173			       struct device_attribute *attr,
174			       char *buf)
175{
176	struct hid_device *hdev = container_of(dev, struct 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
182static DEVICE_ATTR(sensor_physical_width, S_IRUGO, show_phys_width, NULL);
183
184static ssize_t show_phys_height(struct device *dev,
185				struct device_attribute *attr,
186				char *buf)
187{
188	struct hid_device *hdev = container_of(dev, struct 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
194static DEVICE_ATTR(sensor_physical_height, S_IRUGO, show_phys_height, NULL);
195
196static ssize_t show_log_width(struct device *dev,
197			      struct device_attribute *attr,
198			      char *buf)
199{
200	struct hid_device *hdev = container_of(dev, struct 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
206static DEVICE_ATTR(sensor_logical_width, S_IRUGO, show_log_width, NULL);
207
208static ssize_t show_log_height(struct device *dev,
209			       struct device_attribute *attr,
210			       char *buf)
211{
212	struct hid_device *hdev = container_of(dev, struct 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
218static DEVICE_ATTR(sensor_logical_height, S_IRUGO, show_log_height, NULL);
219
220static ssize_t show_min_width(struct device *dev,
221			      struct device_attribute *attr,
222			      char *buf)
223{
224	struct hid_device *hdev = container_of(dev, struct 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
232static 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 = container_of(dev, struct 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
253static DEVICE_ATTR(min_width, S_IWUSR | S_IRUGO, show_min_width, set_min_width);
254
255static ssize_t show_min_height(struct device *dev,
256			       struct device_attribute *attr,
257			       char *buf)
258{
259	struct hid_device *hdev = container_of(dev, struct 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
267static 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 = container_of(dev, struct 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
288static DEVICE_ATTR(min_height, S_IWUSR | S_IRUGO, show_min_height,
289		   set_min_height);
290
291static ssize_t show_activate_slack(struct device *dev,
292				   struct device_attribute *attr,
293				   char *buf)
294{
295	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
296	struct ntrig_data *nd = hid_get_drvdata(hdev);
297
298	return sprintf(buf, "%d\n", nd->activate_slack);
299}
300
301static 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 = container_of(dev, struct 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
321static DEVICE_ATTR(activate_slack, S_IWUSR | S_IRUGO, show_activate_slack,
322		   set_activate_slack);
323
324static ssize_t show_activation_width(struct device *dev,
325				     struct device_attribute *attr,
326				     char *buf)
327{
328	struct hid_device *hdev = container_of(dev, struct 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
336static 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 = container_of(dev, struct 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
357static DEVICE_ATTR(activation_width, S_IWUSR | S_IRUGO, show_activation_width,
358		   set_activation_width);
359
360static ssize_t show_activation_height(struct device *dev,
361				      struct device_attribute *attr,
362				      char *buf)
363{
364	struct hid_device *hdev = container_of(dev, struct 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
372static 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 = container_of(dev, struct 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
393static DEVICE_ATTR(activation_height, S_IWUSR | S_IRUGO,
394		   show_activation_height, set_activation_height);
395
396static ssize_t show_deactivate_slack(struct device *dev,
397				     struct device_attribute *attr,
398				     char *buf)
399{
400	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
401	struct ntrig_data *nd = hid_get_drvdata(hdev);
402
403	return sprintf(buf, "%d\n", -nd->deactivate_slack);
404}
405
406static 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 = container_of(dev, struct 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
431static DEVICE_ATTR(deactivate_slack, S_IWUSR | S_IRUGO, show_deactivate_slack,
432		   set_deactivate_slack);
433
434static 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
448static 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
458static 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
549static 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 */
570static 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 = 1;
595		nd->first_contact_touch = 0;
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 = 0;
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 = 0;
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 = 0;
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
853not_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
862static void 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;
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
895static int ntrig_probe(struct hid_device *hdev, const struct hid_device_id *id)
896{
897	int ret;
898	struct ntrig_data *nd;
899	struct hid_report *report;
900
901	if (id->driver_data)
902		hdev->quirks |= HID_QUIRK_MULTI_INPUT
903				| HID_QUIRK_NO_INIT_REPORTS;
904
905	nd = kmalloc(sizeof(struct ntrig_data), GFP_KERNEL);
906	if (!nd) {
907		hid_err(hdev, "cannot allocate N-Trig data\n");
908		return -ENOMEM;
909	}
910
911	nd->reading_mt = 0;
912	nd->min_width = 0;
913	nd->min_height = 0;
914	nd->activate_slack = activate_slack;
915	nd->act_state = activate_slack;
916	nd->deactivate_slack = -deactivate_slack;
917	nd->sensor_logical_width = 1;
918	nd->sensor_logical_height = 1;
919	nd->sensor_physical_width = 1;
920	nd->sensor_physical_height = 1;
921
922	hid_set_drvdata(hdev, nd);
923
924	ret = hid_parse(hdev);
925	if (ret) {
926		hid_err(hdev, "parse failed\n");
927		goto err_free;
928	}
929
930	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT & ~HID_CONNECT_FF);
931	if (ret) {
932		hid_err(hdev, "hw start failed\n");
933		goto err_free;
934	}
935
936	/* This is needed for devices with more recent firmware versions */
937	report = hdev->report_enum[HID_FEATURE_REPORT].report_id_hash[0x0a];
938	if (report) {
939		/* Let the device settle to ensure the wakeup message gets
940		 * through */
941		hid_hw_wait(hdev);
942		hid_hw_request(hdev, report, HID_REQ_GET_REPORT);
943
944		/*
945		 * Sanity check: if the current mode is invalid reset it to
946		 * something reasonable.
947		 */
948		if (ntrig_get_mode(hdev) >= 4)
949			ntrig_set_mode(hdev, 3);
950	}
951
952	ntrig_report_version(hdev);
953
954	ret = sysfs_create_group(&hdev->dev.kobj,
955			&ntrig_attribute_group);
956
957	return 0;
958err_free:
959	kfree(nd);
960	return ret;
961}
962
963static void ntrig_remove(struct hid_device *hdev)
964{
965	sysfs_remove_group(&hdev->dev.kobj,
966			   &ntrig_attribute_group);
967	hid_hw_stop(hdev);
968	kfree(hid_get_drvdata(hdev));
969}
970
971static const struct hid_device_id ntrig_devices[] = {
972	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN),
973		.driver_data = NTRIG_DUPLICATE_USAGES },
974	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_1),
975		.driver_data = NTRIG_DUPLICATE_USAGES },
976	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_2),
977		.driver_data = NTRIG_DUPLICATE_USAGES },
978	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_3),
979		.driver_data = NTRIG_DUPLICATE_USAGES },
980	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_4),
981		.driver_data = NTRIG_DUPLICATE_USAGES },
982	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_5),
983		.driver_data = NTRIG_DUPLICATE_USAGES },
984	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_6),
985		.driver_data = NTRIG_DUPLICATE_USAGES },
986	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_7),
987		.driver_data = NTRIG_DUPLICATE_USAGES },
988	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_8),
989		.driver_data = NTRIG_DUPLICATE_USAGES },
990	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_9),
991		.driver_data = NTRIG_DUPLICATE_USAGES },
992	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_10),
993		.driver_data = NTRIG_DUPLICATE_USAGES },
994	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_11),
995		.driver_data = NTRIG_DUPLICATE_USAGES },
996	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_12),
997		.driver_data = NTRIG_DUPLICATE_USAGES },
998	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_13),
999		.driver_data = NTRIG_DUPLICATE_USAGES },
1000	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_14),
1001		.driver_data = NTRIG_DUPLICATE_USAGES },
1002	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_15),
1003		.driver_data = NTRIG_DUPLICATE_USAGES },
1004	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_16),
1005		.driver_data = NTRIG_DUPLICATE_USAGES },
1006	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_17),
1007		.driver_data = NTRIG_DUPLICATE_USAGES },
1008	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_18),
1009		.driver_data = NTRIG_DUPLICATE_USAGES },
1010	{ }
1011};
1012MODULE_DEVICE_TABLE(hid, ntrig_devices);
1013
1014static const struct hid_usage_id ntrig_grabbed_usages[] = {
1015	{ HID_ANY_ID, HID_ANY_ID, HID_ANY_ID },
1016	{ HID_ANY_ID - 1, HID_ANY_ID - 1, HID_ANY_ID - 1 }
1017};
1018
1019static struct hid_driver ntrig_driver = {
1020	.name = "ntrig",
1021	.id_table = ntrig_devices,
1022	.probe = ntrig_probe,
1023	.remove = ntrig_remove,
1024	.input_mapping = ntrig_input_mapping,
1025	.input_mapped = ntrig_input_mapped,
1026	.input_configured = ntrig_input_configured,
1027	.usage_table = ntrig_grabbed_usages,
1028	.event = ntrig_event,
1029};
1030module_hid_driver(ntrig_driver);
1031
1032MODULE_LICENSE("GPL");
1033