summaryrefslogtreecommitdiffstats
path: root/kernel/drivers/input/joystick/sidewinder.c
blob: 4a95b224169f33f32fbc106a97add8a5b62e141b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
/*
 *  Copyright (c) 1998-2005 Vojtech Pavlik
 */

/*
 * Microsoft SideWinder joystick family driver for Linux
 */

/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Should you need to contact me, the author, you can do so either by
 * e-mail - mail your message to <vojtech@ucw.cz>, or by paper mail:
 * Vojtech Pavlik, Simunkova 1594, Prague 8, 182 00 Czech Republic
 */

#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/gameport.h>
#include <linux/jiffies.h>

#define DRIVER_DESC	"Microsoft SideWinder joystick family driver"

MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

/*
 * These are really magic values. Changing them can make a problem go away,
 * as well as break everything.
 */

#undef SW_DEBUG
#undef SW_DEBUG_DATA

#define SW_START	600	/* The time we wait for the first bit [600 us] */
#define SW_STROBE	60	/* Max time per bit [60 us] */
#define SW_TIMEOUT	6	/* Wait for everything to settle [6 ms] */
#define SW_KICK		45	/* Wait after A0 fall till kick [45 us] */
#define SW_END		8	/* Number of bits before end of packet to kick */
#define SW_FAIL		16	/* Number of packet read errors to fail and reinitialize */
#define SW_BAD		2	/* Number of packet read errors to switch off 3d Pro optimization */
#define SW_OK		64	/* Number of packet read successes to switch optimization back on */
#define SW_LENGTH	512	/* Max number of bits in a packet */

#ifdef SW_DEBUG
#define dbg(format, arg...) printk(KERN_DEBUG __FILE__ ": " format "\n" , ## arg)
#else
#define dbg(format, arg...) do {} while (0)
#endif

/*
 * SideWinder joystick types ...
 */

#define SW_ID_3DP	0
#define SW_ID_GP	1
#define SW_ID_PP	2
#define SW_ID_FFP	3
#define SW_ID_FSP	4
#define SW_ID_FFW	5

/*
 * Names, buttons, axes ...
 */

static char *sw_name[] = {	"3D Pro", "GamePad", "Precision Pro", "Force Feedback Pro", "FreeStyle Pro",
				"Force Feedback Wheel" };

static char sw_abs[][7] = {
	{ ABS_X, ABS_Y, ABS_RZ, ABS_THROTTLE, ABS_HAT0X, ABS_HAT0Y },
	{ ABS_X, ABS_Y },
	{ ABS_X, ABS_Y, ABS_RZ, ABS_THROTTLE, ABS_HAT0X, ABS_HAT0Y },
	{ ABS_X, ABS_Y, ABS_RZ, ABS_THROTTLE, ABS_HAT0X, ABS_HAT0Y },
	{ ABS_X, ABS_Y,         ABS_THROTTLE, ABS_HAT0X, ABS_HAT0Y },
	{ ABS_RX, ABS_RUDDER,   ABS_THROTTLE }};

static char sw_bit[][7] = {
	{ 10, 10,  9, 10,  1,  1 },
	{  1,  1                 },
	{ 10, 10,  6,  7,  1,  1 },
	{ 10, 10,  6,  7,  1,  1 },
	{ 10, 10,  6,  1,  1     },
	{ 10,  7,  7,  1,  1     }};

static short sw_btn[][12] = {
	{ BTN_TRIGGER, BTN_TOP, BTN_THUMB, BTN_THUMB2, BTN_BASE, BTN_BASE2, BTN_BASE3, BTN_BASE4, BTN_MODE },
	{ BTN_A, BTN_B, BTN_C, BTN_X, BTN_Y, BTN_Z, BTN_TL, BTN_TR, BTN_START, BTN_MODE },
	{ BTN_TRIGGER, BTN_THUMB, BTN_TOP, BTN_TOP2, BTN_BASE, BTN_BASE2, BTN_BASE3, BTN_BASE4, BTN_SELECT },
	{ BTN_TRIGGER, BTN_THUMB, BTN_TOP, BTN_TOP2, BTN_BASE, BTN_BASE2, BTN_BASE3, BTN_BASE4, BTN_SELECT },
	{ BTN_A, BTN_B, BTN_C, BTN_X, BTN_Y, BTN_Z, BTN_TL, BTN_TR, BTN_START, BTN_MODE, BTN_SELECT },
	{ BTN_TRIGGER, BTN_TOP, BTN_THUMB, BTN_THUMB2, BTN_BASE, BTN_BASE2, BTN_BASE3, BTN_BASE4 }};

static struct {
	int x;
	int y;
} sw_hat_to_axis[] = {{ 0, 0}, { 0,-1}, { 1,-1}, { 1, 0}, { 1, 1}, { 0, 1}, {-1, 1}, {-1, 0}, {-1,-1}};

struct sw {
	struct gameport *gameport;
	struct input_dev *dev[4];
	char name[64];
	char phys[4][32];
	int length;
	int type;
	int bits;
	int number;
	int fail;
	int ok;
	int reads;
	int bads;
};

/*
 * sw_read_packet() is a function which reads either a data packet, or an
 * identification packet from a SideWinder joystick. The protocol is very,
 * very, very braindamaged. Microsoft patented it in US patent #5628686.
 */

static int sw_read_packet(struct gameport *gameport, unsigned char *buf, int length, int id)
{
	unsigned long flags;
	int timeout, bitout, sched, i, kick, start, strobe;
	unsigned char pending, u, v;

	i = -id;						/* Don't care about data, only want ID */
	timeout = id ? gameport_time(gameport, SW_TIMEOUT * 1000) : 0; /* Set up global timeout for ID packet */
	kick = id ? gameport_time(gameport, SW_KICK) : 0;	/* Set up kick timeout for ID packet */
	start = gameport_time(gameport, SW_START);
	strobe = gameport_time(gameport, SW_STROBE);
	bitout = start;
	pending = 0;
	sched = 0;

        local_irq_save(flags);					/* Quiet, please */

	gameport_trigger(gameport);				/* Trigger */
	v = gameport_read(gameport);

	do {
		bitout--;
		u = v;
		v = gameport_read(gameport);
	} while (!(~v & u & 0x10) && (bitout > 0));		/* Wait for first falling edge on clock */

	if (bitout > 0)
		bitout = strobe;				/* Extend time if not timed out */

	while ((timeout > 0 || bitout > 0) && (i < length)) {

		timeout--;
		bitout--;					/* Decrement timers */
		sched--;

		u = v;
		v = gameport_read(gameport);

		if ((~u & v & 0x10) && (bitout > 0)) {		/* Rising edge on clock - data bit */
			if (i >= 0)				/* Want this data */
				buf[i] = v >> 5;		/* Store it */
			i++;					/* Advance index */
			bitout = strobe;			/* Extend timeout for next bit */
		}

		if (kick && (~v & u & 0x01)) {			/* Falling edge on axis 0 */
			sched = kick;				/* Schedule second trigger */
			kick = 0;				/* Don't schedule next time on falling edge */
			pending = 1;				/* Mark schedule */
		}

		if (pending && sched < 0 && (i > -SW_END)) {	/* Second trigger time */
			gameport_trigger(gameport);		/* Trigger */
			bitout = start;				/* Long bit timeout */
			pending = 0;				/* Unmark schedule */
			timeout = 0;				/* Switch from global to bit timeouts */
		}
	}

	local_irq_restore(flags);					/* Done - relax */

#ifdef SW_DEBUG_DATA
	{
		int j;
		printk(KERN_DEBUG "sidewinder.c: Read %d triplets. [", i);
		for (j = 0; j < i; j++) printk("%d", buf[j]);
		printk("]\n");
	}
#endif

	return i;
}

/*
 * sw_get_bits() and GB() compose bits from the triplet buffer into a __u64.
 * Parameter 'pos' is bit number inside packet where to start at, 'num' is number
 * of bits to be read, 'shift' is offset in the resulting __u64 to start at, bits
 * is number of bits per triplet.
 */

#define GB(pos,num) sw_get_bits(buf, pos, num, sw->bits)

static __u64 sw_get_bits(unsigned char *buf, int pos, int num, char bits)
{
	__u64 data = 0;
	int tri = pos % bits;						/* Start position */
	int i   = pos / bits;
	int bit = 0;

	while (num--) {
		data |= (__u64)((buf[i] >> tri++) & 1) << bit++;	/* Transfer bit */
		if (tri == bits) {
			i++;						/* Next triplet */
			tri = 0;
		}
	}

	return data;
}

/*
 * sw_init_digital() initializes a SideWinder 3D Pro joystick
 * into digital mode.
 */

static void sw_init_digital(struct gameport *gameport)
{
	int seq[] = { 140, 140+725, 140+300, 0 };
	unsigned long flags;
	int i, t;

        local_irq_save(flags);

	i = 0;
        do {
                gameport_trigger(gameport);			/* Trigger */
		t = gameport_time(gameport, SW_TIMEOUT * 1000);
		while ((gameport_read(gameport) & 1) && t) t--;	/* Wait for axis to fall back to 0 */
                udelay(seq[i]);					/* Delay magic time */
        } while (seq[++i]);

	gameport_trigger(gameport);				/* Last trigger */

	local_irq_restore(flags);
}

/*
 * sw_parity() computes parity of __u64
 */

static int sw_parity(__u64 t)
{
	int x = t ^ (t >> 32);

	x ^= x >> 16;
	x ^= x >> 8;
	x ^= x >> 4;
	x ^= x >> 2;
	x ^= x >> 1;
	return x & 1;
}

/*
 * sw_ccheck() checks synchronization bits and computes checksum of nibbles.
 */

static int sw_check(__u64 t)
{
	unsigned char sum = 0;

	if ((t & 0x8080808080808080ULL) ^ 0x80)			/* Sync */
		return -1;

	while (t) {						/* Sum */
		sum += t & 0xf;
		t >>= 4;
	}

	return sum & 0xf;
}

/*
 * sw_parse() analyzes SideWinder joystick data, and writes the results into
 * the axes and buttons arrays.
 */

static int sw_parse(unsigned char *buf, struct sw *sw)
{
	int hat, i, j;
	struct input_dev *dev;

	switch (sw->type) {

		case SW_ID_3DP:

			if (sw_check(GB(0,64)) || (hat = (GB(6,1) << 3) | GB(60,3)) > 8)
				return -1;

			dev = sw->dev[0];

			input_report_abs(dev, ABS_X,        (GB( 3,3) << 7) | GB(16,7));
			input_report_abs(dev, ABS_Y,        (GB( 0,3) << 7) | GB(24,7));
			input_report_abs(dev, ABS_RZ,       (GB(35,2) << 7) | GB(40,7));
			input_report_abs(dev, ABS_THROTTLE, (GB(32,3) << 7) | GB(48,7));

			input_report_abs(dev, ABS_HAT0X, sw_hat_to_axis[hat].x);
			input_report_abs(dev, ABS_HAT0Y, sw_hat_to_axis[hat].y);

			for (j = 0; j < 7; j++)
				input_report_key(dev, sw_btn[SW_ID_3DP][j], !GB(j+8,1));

			input_report_key(dev, BTN_BASE4, !GB(38,1));
			input_report_key(dev, BTN_BASE5, !GB(37,1));

			input_sync(dev);

			return 0;

		case SW_ID_GP:

			for (i = 0; i < sw->number; i ++) {

				if (sw_parity(GB(i*15,15)))
					return -1;

				input_report_abs(sw->dev[i], ABS_X, GB(i*15+3,1) - GB(i*15+2,1));
				input_report_abs(sw->dev[i], ABS_Y, GB(i*15+0,1) - GB(i*15+1,1));

				for (j = 0; j < 10; j++)
					input_report_key(sw->dev[i], sw_btn[SW_ID_GP][j], !GB(i*15+j+4,1));

				input_sync(sw->dev[i]);
			}

			return 0;

		case SW_ID_PP:
		case SW_ID_FFP:

			if (!sw_parity(GB(0,48)) || (hat = GB(42,4)) > 8)
				return -1;

			dev = sw->dev[0];
			input_report_abs(dev, ABS_X,        GB( 9,10));
			input_report_abs(dev, ABS_Y,        GB(19,10));
			input_report_abs(dev, ABS_RZ,       GB(36, 6));
			input_report_abs(dev, ABS_THROTTLE, GB(29, 7));

			input_report_abs(dev, ABS_HAT0X, sw_hat_to_axis[hat].x);
			input_report_abs(dev, ABS_HAT0Y, sw_hat_to_axis[hat].y);

			for (j = 0; j < 9; j++)
				input_report_key(dev, sw_btn[SW_ID_PP][j], !GB(j,1));

			input_sync(dev);

			return 0;

		case SW_ID_FSP:

			if (!sw_parity(GB(0,43)) || (hat = GB(28,4)) > 8)
				return -1;

			dev = sw->dev[0];
			input_report_abs(dev, ABS_X,        GB( 0,10));
			input_report_abs(dev, ABS_Y,        GB(16,10));
			input_report_abs(dev, ABS_THROTTLE, GB(32, 6));

			input_report_abs(dev, ABS_HAT0X, sw_hat_to_axis[hat].x);
			input_report_abs(dev, ABS_HAT0Y, sw_hat_to_axis[hat].y);

			for (j = 0; j < 6; j++)
				input_report_key(dev, sw_btn[SW_ID_FSP][j], !GB(j+10,1));

			input_report_key(dev, BTN_TR,     !GB(26,1));
			input_report_key(dev, BTN_START,  !GB(27,1));
			input_report_key(dev, BTN_MODE,   !GB(38,1));
			input_report_key(dev, BTN_SELECT, !GB(39,1));

			input_sync(dev);

			return 0;

		case SW_ID_FFW:

			if (!sw_parity(GB(0,33)))
				return -1;

			dev = sw->dev[0];
			input_report_abs(dev, ABS_RX,       GB( 0,10));
			input_report_abs(dev, ABS_RUDDER,   GB(10, 6));
			input_report_abs(dev, ABS_THROTTLE, GB(16, 6));

			for (j = 0; j < 8; j++)
				input_report_key(dev, sw_btn[SW_ID_FFW][j], !GB(j+22,1));

			input_sync(dev);

			return 0;
	}

	return -1;
}

/*
 * sw_read() reads SideWinder joystick data, and reinitializes
 * the joystick in case of persistent problems. This is the function that is
 * called from the generic code to poll the joystick.
 */

static int sw_read(struct sw *sw)
{
	unsigned char buf[SW_LENGTH];
	int i;

	i = sw_read_packet(sw->gameport, buf, sw->length, 0);

	if (sw->type == SW_ID_3DP && sw->length == 66 && i != 66) {		/* Broken packet, try to fix */

		if (i == 64 && !sw_check(sw_get_bits(buf,0,64,1))) {		/* Last init failed, 1 bit mode */
			printk(KERN_WARNING "sidewinder.c: Joystick in wrong mode on %s"
				" - going to reinitialize.\n", sw->gameport->phys);
			sw->fail = SW_FAIL;					/* Reinitialize */
			i = 128;						/* Bogus value */
		}

		if (i < 66 && GB(0,64) == GB(i*3-66,64))			/* 1 == 3 */
			i = 66;							/* Everything is fine */

		if (i < 66 && GB(0,64) == GB(66,64))				/* 1 == 2 */
			i = 66;							/* Everything is fine */

		if (i < 66 && GB(i*3-132,64) == GB(i*3-66,64)) {		/* 2 == 3 */
			memmove(buf, buf + i - 22, 22);				/* Move data */
			i = 66;							/* Carry on */
		}
	}

	if (i == sw->length && !sw_parse(buf, sw)) {				/* Parse data */

		sw->fail = 0;
		sw->ok++;

		if (sw->type == SW_ID_3DP && sw->length == 66			/* Many packets OK */
			&& sw->ok > SW_OK) {

			printk(KERN_INFO "sidewinder.c: No more trouble on %s"
				" - enabling optimization again.\n", sw->gameport->phys);
			sw->length = 22;
		}

		return 0;
	}

	sw->ok = 0;
	sw->fail++;

	if (sw->type == SW_ID_3DP && sw->length == 22 && sw->fail > SW_BAD) {	/* Consecutive bad packets */

		printk(KERN_INFO "sidewinder.c: Many bit errors on %s"
			" - disabling optimization.\n", sw->gameport->phys);
		sw->length = 66;
	}

	if (sw->fail < SW_FAIL)
		return -1;							/* Not enough, don't reinitialize yet */

	printk(KERN_WARNING "sidewinder.c: Too many bit errors on %s"
		" - reinitializing joystick.\n", sw->gameport->phys);

	if (!i && sw->type == SW_ID_3DP) {					/* 3D Pro can be in analog mode */
		mdelay(3 * SW_TIMEOUT);
		sw_init_digital(sw->gameport);
	}

	mdelay(SW_TIMEOUT);
	i = sw_read_packet(sw->gameport, buf, SW_LENGTH, 0);			/* Read normal data packet */
	mdelay(SW_TIMEOUT);
	sw_read_packet(sw->gameport, buf, SW_LENGTH, i);			/* Read ID packet, this initializes the stick */

	sw->fail = SW_FAIL;

	return -1;
}

static void sw_poll(struct gameport *gameport)
{
	struct sw *sw = gameport_get_drvdata(gameport);

	sw->reads++;
	if (sw_read(sw))
		sw->bads++;
}

static int sw_open(struct input_dev *dev)
{
	struct sw *sw = input_get_drvdata(dev);

	gameport_start_polling(sw->gameport);
	return 0;
}

static void sw_close(struct input_dev *dev)
{
	struct sw *sw = input_get_drvdata(dev);

	gameport_stop_polling(sw->gameport);
}

/*
 * sw_print_packet() prints the contents of a SideWinder packet.
 */

static void sw_print_packet(char *name, int length, unsigned char *buf, char bits)
{
	int i;

	printk(KERN_INFO "sidewinder.c: %s packet, %d bits. [", name, length);
	for (i = (((length + 3) >> 2) - 1); i >= 0; i--)
		printk("%x", (int)sw_get_bits(buf, i << 2, 4, bits));
	printk("]\n");
}

/*
 * sw_3dp_id() translates the 3DP id into a human legible string.
 * Unfortunately I don't know how to do this for the other SW types.
 */

static void sw_3dp_id(unsigned char *buf, char *comment, size_t size)
{
	int i;
	char pnp[8], rev[9];

	for (i = 0; i < 7; i++)						/* ASCII PnP ID */
		pnp[i] = sw_get_bits(buf, 24+8*i, 8, 1);

	for (i = 0; i < 8; i++)						/* ASCII firmware revision */
		rev[i] = sw_get_bits(buf, 88+8*i, 8, 1);

	pnp[7] = rev[8] = 0;

	snprintf(comment, size, " [PnP %d.%02d id %s rev %s]",
		(int) ((sw_get_bits(buf, 8, 6, 1) << 6) |		/* Two 6-bit values */
			sw_get_bits(buf, 16, 6, 1)) / 100,
		(int) ((sw_get_bits(buf, 8, 6, 1) << 6) |
			sw_get_bits(buf, 16, 6, 1)) % 100,
		 pnp, rev);
}

/*
 * sw_guess_mode() checks the upper two button bits for toggling -
 * indication of that the joystick is in 3-bit mode. This is documented
 * behavior for 3DP ID packet, and for example the FSP does this in
 * normal packets instead. Fun ...
 */

static int sw_guess_mode(unsigned char *buf, int len)
{
	int i;
	unsigned char xor = 0;

	for (i = 1; i < len; i++)
		xor |= (buf[i - 1] ^ buf[i]) & 6;

	return !!xor * 2 + 1;
}

/*
 * sw_connect() probes for SideWinder type joysticks.
 */

static int sw_connect(struct gameport *gameport, struct gameport_driver *drv)
{
	struct sw *sw;
	struct input_dev *input_dev;
	int i, j, k, l;
	int err = 0;
	unsigned char *buf = NULL;	/* [SW_LENGTH] */
	unsigned char *idbuf = NULL;	/* [SW_LENGTH] */
	unsigned char m = 1;
	char comment[40];

	comment[0] = 0;

	sw = kzalloc(sizeof(struct sw), GFP_KERNEL);
	buf = kmalloc(SW_LENGTH, GFP_KERNEL);
	idbuf = kmalloc(SW_LENGTH, GFP_KERNEL);
	if (!sw || !buf || !idbuf) {
		err = -ENOMEM;
		goto fail1;
	}

	sw->gameport = gameport;

	gameport_set_drvdata(gameport, sw);

	err = gameport_open(gameport, drv, GAMEPORT_MODE_RAW);
	if (err)
		goto fail1;

	dbg("Init 0: Opened %s, io %#x, speed %d",
		gameport->phys, gameport->io, gameport->speed);

	i = sw_read_packet(gameport, buf, SW_LENGTH, 0);		/* Read normal packet */
	msleep(SW_TIMEOUT);
	dbg("Init 1: Mode %d. Length %d.", m , i);

	if (!i) {							/* No data. 3d Pro analog mode? */
		sw_init_digital(gameport);				/* Switch to digital */
		msleep(SW_TIMEOUT);
		i = sw_read_packet(gameport, buf, SW_LENGTH, 0);	/* Retry reading packet */
		msleep(SW_TIMEOUT);
		dbg("Init 1b: Length %d.", i);
		if (!i) {						/* No data -> FAIL */
			err = -ENODEV;
			goto fail2;
		}
	}

	j = sw_read_packet(gameport, idbuf, SW_LENGTH, i);		/* Read ID. This initializes the stick */
	m |= sw_guess_mode(idbuf, j);					/* ID packet should carry mode info [3DP] */
	dbg("Init 2: Mode %d. ID Length %d.", m, j);

	if (j <= 0) {							/* Read ID failed. Happens in 1-bit mode on PP */
		msleep(SW_TIMEOUT);
		i = sw_read_packet(gameport, buf, SW_LENGTH, 0);	/* Retry reading packet */
		m |= sw_guess_mode(buf, i);
		dbg("Init 2b: Mode %d. Length %d.", m, i);
		if (!i) {
			err = -ENODEV;
			goto fail2;
		}
		msleep(SW_TIMEOUT);
		j = sw_read_packet(gameport, idbuf, SW_LENGTH, i);	/* Retry reading ID */
		dbg("Init 2c: ID Length %d.", j);
	}

	sw->type = -1;
	k = SW_FAIL;							/* Try SW_FAIL times */
	l = 0;

	do {
		k--;
		msleep(SW_TIMEOUT);
		i = sw_read_packet(gameport, buf, SW_LENGTH, 0);	/* Read data packet */
		dbg("Init 3: Mode %d. Length %d. Last %d. Tries %d.", m, i, l, k);

		if (i > l) {						/* Longer? As we can only lose bits, it makes */
									/* no sense to try detection for a packet shorter */
			l = i;						/* than the previous one */

			sw->number = 1;
			sw->gameport = gameport;
			sw->length = i;
			sw->bits = m;

			dbg("Init 3a: Case %d.\n", i * m);

			switch (i * m) {
				case 60:
					sw->number++;
				case 45:				/* Ambiguous packet length */
					if (j <= 40) {			/* ID length less or eq 40 -> FSP */
				case 43:
						sw->type = SW_ID_FSP;
						break;
					}
					sw->number++;
				case 30:
					sw->number++;
				case 15:
					sw->type = SW_ID_GP;
					break;
				case 33:
				case 31:
					sw->type = SW_ID_FFW;
					break;
				case 48:				/* Ambiguous */
					if (j == 14) {			/* ID length 14*3 -> FFP */
						sw->type = SW_ID_FFP;
						sprintf(comment, " [AC %s]", sw_get_bits(idbuf,38,1,3) ? "off" : "on");
					} else
						sw->type = SW_ID_PP;
					break;
				case 66:
					sw->bits = 3;
				case 198:
					sw->length = 22;
				case 64:
					sw->type = SW_ID_3DP;
					if (j == 160)
						sw_3dp_id(idbuf, comment, sizeof(comment));
					break;
			}
		}

	} while (k && sw->type == -1);

	if (sw->type == -1) {
		printk(KERN_WARNING "sidewinder.c: unknown joystick device detected "
			"on %s, contact <vojtech@ucw.cz>\n", gameport->phys);
		sw_print_packet("ID", j * 3, idbuf, 3);
		sw_print_packet("Data", i * m, buf, m);
		err = -ENODEV;
		goto fail2;
	}

#ifdef SW_DEBUG
	sw_print_packet("ID", j * 3, idbuf, 3);
	sw_print_packet("Data", i * m, buf, m);
#endif

	gameport_set_poll_handler(gameport, sw_poll);
	gameport_set_poll_interval(gameport, 20);

	k = i;
	l = j;

	for (i = 0; i < sw->number; i++) {
		int bits, code;

		snprintf(sw->name, sizeof(sw->name),
			 "Microsoft SideWinder %s", sw_name[sw->type]);
		snprintf(sw->phys[i], sizeof(sw->phys[i]),
			 "%s/input%d", gameport->phys, i);

		sw->dev[i] = input_dev = input_allocate_device();
		if (!input_dev) {
			err = -ENOMEM;
			goto fail3;
		}

		input_dev->name = sw->name;
		input_dev->phys = sw->phys[i];
		input_dev->id.bustype = BUS_GAMEPORT;
		input_dev->id.vendor = GAMEPORT_ID_VENDOR_MICROSOFT;
		input_dev->id.product = sw->type;
		input_dev->id.version = 0x0100;
		input_dev->dev.parent = &gameport->dev;

		input_set_drvdata(input_dev, sw);

		input_dev->open = sw_open;
		input_dev->close = sw_close;

		input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);

		for (j = 0; (bits = sw_bit[sw->type][j]); j++) {
			int min, max, fuzz, flat;

			code = sw_abs[sw->type][j];
			min = bits == 1 ? -1 : 0;
			max = (1 << bits) - 1;
			fuzz = (bits >> 1) >= 2 ? 1 << ((bits >> 1) - 2) : 0;
			flat = code == ABS_THROTTLE || bits < 5 ?
				0 : 1 << (bits - 5);

			input_set_abs_params(input_dev, code,
					     min, max, fuzz, flat);
		}

		for (j = 0; (code = sw_btn[sw->type][j]); j++)
			__set_bit(code, input_dev->keybit);

		dbg("%s%s [%d-bit id %d data %d]\n", sw->name, comment, m, l, k);

		err = input_register_device(sw->dev[i]);
		if (err)
			goto fail4;
	}

 out:	kfree(buf);
	kfree(idbuf);

	return err;

 fail4:	input_free_device(sw->dev[i]);
 fail3:	while (--i >= 0)
		input_unregister_device(sw->dev[i]);
 fail2:	gameport_close(gameport);
 fail1:	gameport_set_drvdata(gameport, NULL);
	kfree(sw);
	goto out;
}

static void sw_disconnect(struct gameport *gameport)
{
	struct sw *sw = gameport_get_drvdata(gameport);
	int i;

	for (i = 0; i < sw->number; i++)
		input_unregister_device(sw->dev[i]);
	gameport_close(gameport);
	gameport_set_drvdata(gameport, NULL);
	kfree(sw);
}

static struct gameport_driver sw_drv = {
	.driver		= {
		.name	= "sidewinder",
		.owner	= THIS_MODULE,
	},
	.description	= DRIVER_DESC,
	.connect	= sw_connect,
	.disconnect	= sw_disconnect,
};

module_gameport_driver(sw_drv);