xref: /linux/drivers/input/joystick/sidewinder.c (revision 41e0d49104dbff888ef6446ea46842fde66c0a76)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Copyright (c) 1998-2005 Vojtech Pavlik
4  */
5 
6 /*
7  * Microsoft SideWinder joystick family driver for Linux
8  */
9 
10 #include <linux/delay.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/input.h>
15 #include <linux/gameport.h>
16 #include <linux/jiffies.h>
17 
18 #define DRIVER_DESC	"Microsoft SideWinder joystick family driver"
19 
20 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
21 MODULE_DESCRIPTION(DRIVER_DESC);
22 MODULE_LICENSE("GPL");
23 
24 /*
25  * These are really magic values. Changing them can make a problem go away,
26  * as well as break everything.
27  */
28 
29 #undef SW_DEBUG
30 #undef SW_DEBUG_DATA
31 
32 #define SW_START	600	/* The time we wait for the first bit [600 us] */
33 #define SW_STROBE	60	/* Max time per bit [60 us] */
34 #define SW_TIMEOUT	6	/* Wait for everything to settle [6 ms] */
35 #define SW_KICK		45	/* Wait after A0 fall till kick [45 us] */
36 #define SW_END		8	/* Number of bits before end of packet to kick */
37 #define SW_FAIL		16	/* Number of packet read errors to fail and reinitialize */
38 #define SW_BAD		2	/* Number of packet read errors to switch off 3d Pro optimization */
39 #define SW_OK		64	/* Number of packet read successes to switch optimization back on */
40 #define SW_LENGTH	512	/* Max number of bits in a packet */
41 
42 #ifdef SW_DEBUG
43 #define dbg(format, arg...) printk(KERN_DEBUG __FILE__ ": " format "\n" , ## arg)
44 #else
45 #define dbg(format, arg...) do {} while (0)
46 #endif
47 
48 /*
49  * SideWinder joystick types ...
50  */
51 
52 #define SW_ID_3DP	0
53 #define SW_ID_GP	1
54 #define SW_ID_PP	2
55 #define SW_ID_FFP	3
56 #define SW_ID_FSP	4
57 #define SW_ID_FFW	5
58 
59 /*
60  * Names, buttons, axes ...
61  */
62 
63 static char *sw_name[] = {	"3D Pro", "GamePad", "Precision Pro", "Force Feedback Pro", "FreeStyle Pro",
64 				"Force Feedback Wheel" };
65 
66 static char sw_abs[][7] = {
67 	{ ABS_X, ABS_Y, ABS_RZ, ABS_THROTTLE, ABS_HAT0X, ABS_HAT0Y },
68 	{ ABS_X, ABS_Y },
69 	{ ABS_X, ABS_Y, ABS_RZ, ABS_THROTTLE, ABS_HAT0X, ABS_HAT0Y },
70 	{ ABS_X, ABS_Y, ABS_RZ, ABS_THROTTLE, ABS_HAT0X, ABS_HAT0Y },
71 	{ ABS_X, ABS_Y,         ABS_THROTTLE, ABS_HAT0X, ABS_HAT0Y },
72 	{ ABS_RX, ABS_RUDDER,   ABS_THROTTLE }};
73 
74 static char sw_bit[][7] = {
75 	{ 10, 10,  9, 10,  1,  1 },
76 	{  1,  1                 },
77 	{ 10, 10,  6,  7,  1,  1 },
78 	{ 10, 10,  6,  7,  1,  1 },
79 	{ 10, 10,  6,  1,  1     },
80 	{ 10,  7,  7,  1,  1     }};
81 
82 static short sw_btn[][12] = {
83 	{ BTN_TRIGGER, BTN_TOP, BTN_THUMB, BTN_THUMB2, BTN_BASE, BTN_BASE2, BTN_BASE3, BTN_BASE4, BTN_MODE },
84 	{ BTN_A, BTN_B, BTN_C, BTN_X, BTN_Y, BTN_Z, BTN_TL, BTN_TR, BTN_START, BTN_MODE },
85 	{ BTN_TRIGGER, BTN_THUMB, BTN_TOP, BTN_TOP2, BTN_BASE, BTN_BASE2, BTN_BASE3, BTN_BASE4, BTN_SELECT },
86 	{ BTN_TRIGGER, BTN_THUMB, BTN_TOP, BTN_TOP2, BTN_BASE, BTN_BASE2, BTN_BASE3, BTN_BASE4, BTN_SELECT },
87 	{ BTN_A, BTN_B, BTN_C, BTN_X, BTN_Y, BTN_Z, BTN_TL, BTN_TR, BTN_START, BTN_MODE, BTN_SELECT },
88 	{ BTN_TRIGGER, BTN_TOP, BTN_THUMB, BTN_THUMB2, BTN_BASE, BTN_BASE2, BTN_BASE3, BTN_BASE4 }};
89 
90 static struct {
91 	int x;
92 	int y;
93 } sw_hat_to_axis[] = {{ 0, 0}, { 0,-1}, { 1,-1}, { 1, 0}, { 1, 1}, { 0, 1}, {-1, 1}, {-1, 0}, {-1,-1}};
94 
95 struct sw {
96 	struct gameport *gameport;
97 	struct input_dev *dev[4];
98 	char name[64];
99 	char phys[4][32];
100 	int length;
101 	int type;
102 	int bits;
103 	int number;
104 	int fail;
105 	int ok;
106 	int reads;
107 	int bads;
108 };
109 
110 /*
111  * sw_read_packet() is a function which reads either a data packet, or an
112  * identification packet from a SideWinder joystick. The protocol is very,
113  * very, very braindamaged. Microsoft patented it in US patent #5628686.
114  */
115 
116 static int sw_read_packet(struct gameport *gameport, unsigned char *buf, int length, int id)
117 {
118 	unsigned long flags;
119 	int timeout, bitout, sched, i, kick, start, strobe;
120 	unsigned char pending, u, v;
121 
122 	i = -id;						/* Don't care about data, only want ID */
123 	timeout = id ? gameport_time(gameport, SW_TIMEOUT * 1000) : 0; /* Set up global timeout for ID packet */
124 	kick = id ? gameport_time(gameport, SW_KICK) : 0;	/* Set up kick timeout for ID packet */
125 	start = gameport_time(gameport, SW_START);
126 	strobe = gameport_time(gameport, SW_STROBE);
127 	bitout = start;
128 	pending = 0;
129 	sched = 0;
130 
131         local_irq_save(flags);					/* Quiet, please */
132 
133 	gameport_trigger(gameport);				/* Trigger */
134 	v = gameport_read(gameport);
135 
136 	do {
137 		bitout--;
138 		u = v;
139 		v = gameport_read(gameport);
140 	} while (!(~v & u & 0x10) && (bitout > 0));		/* Wait for first falling edge on clock */
141 
142 	if (bitout > 0)
143 		bitout = strobe;				/* Extend time if not timed out */
144 
145 	while ((timeout > 0 || bitout > 0) && (i < length)) {
146 
147 		timeout--;
148 		bitout--;					/* Decrement timers */
149 		sched--;
150 
151 		u = v;
152 		v = gameport_read(gameport);
153 
154 		if ((~u & v & 0x10) && (bitout > 0)) {		/* Rising edge on clock - data bit */
155 			if (i >= 0)				/* Want this data */
156 				buf[i] = v >> 5;		/* Store it */
157 			i++;					/* Advance index */
158 			bitout = strobe;			/* Extend timeout for next bit */
159 		}
160 
161 		if (kick && (~v & u & 0x01)) {			/* Falling edge on axis 0 */
162 			sched = kick;				/* Schedule second trigger */
163 			kick = 0;				/* Don't schedule next time on falling edge */
164 			pending = 1;				/* Mark schedule */
165 		}
166 
167 		if (pending && sched < 0 && (i > -SW_END)) {	/* Second trigger time */
168 			gameport_trigger(gameport);		/* Trigger */
169 			bitout = start;				/* Long bit timeout */
170 			pending = 0;				/* Unmark schedule */
171 			timeout = 0;				/* Switch from global to bit timeouts */
172 		}
173 	}
174 
175 	local_irq_restore(flags);					/* Done - relax */
176 
177 #ifdef SW_DEBUG_DATA
178 	{
179 		int j;
180 		printk(KERN_DEBUG "sidewinder.c: Read %d triplets. [", i);
181 		for (j = 0; j < i; j++) printk("%d", buf[j]);
182 		printk("]\n");
183 	}
184 #endif
185 
186 	return i;
187 }
188 
189 /*
190  * sw_get_bits() and GB() compose bits from the triplet buffer into a __u64.
191  * Parameter 'pos' is bit number inside packet where to start at, 'num' is number
192  * of bits to be read, 'shift' is offset in the resulting __u64 to start at, bits
193  * is number of bits per triplet.
194  */
195 
196 #define GB(pos,num) sw_get_bits(buf, pos, num, sw->bits)
197 
198 static __u64 sw_get_bits(unsigned char *buf, int pos, int num, char bits)
199 {
200 	__u64 data = 0;
201 	int tri = pos % bits;						/* Start position */
202 	int i   = pos / bits;
203 	int bit = 0;
204 
205 	while (num--) {
206 		data |= (__u64)((buf[i] >> tri++) & 1) << bit++;	/* Transfer bit */
207 		if (tri == bits) {
208 			i++;						/* Next triplet */
209 			tri = 0;
210 		}
211 	}
212 
213 	return data;
214 }
215 
216 /*
217  * sw_init_digital() initializes a SideWinder 3D Pro joystick
218  * into digital mode.
219  */
220 
221 static void sw_init_digital(struct gameport *gameport)
222 {
223 	static const int seq[] = { 140, 140+725, 140+300, 0 };
224 	unsigned long flags;
225 	int i, t;
226 
227         local_irq_save(flags);
228 
229 	i = 0;
230         do {
231                 gameport_trigger(gameport);			/* Trigger */
232 		t = gameport_time(gameport, SW_TIMEOUT * 1000);
233 		while ((gameport_read(gameport) & 1) && t) t--;	/* Wait for axis to fall back to 0 */
234                 udelay(seq[i]);					/* Delay magic time */
235         } while (seq[++i]);
236 
237 	gameport_trigger(gameport);				/* Last trigger */
238 
239 	local_irq_restore(flags);
240 }
241 
242 /*
243  * sw_parity() computes parity of __u64
244  */
245 
246 static int sw_parity(__u64 t)
247 {
248 	int x = t ^ (t >> 32);
249 
250 	x ^= x >> 16;
251 	x ^= x >> 8;
252 	x ^= x >> 4;
253 	x ^= x >> 2;
254 	x ^= x >> 1;
255 	return x & 1;
256 }
257 
258 /*
259  * sw_ccheck() checks synchronization bits and computes checksum of nibbles.
260  */
261 
262 static int sw_check(__u64 t)
263 {
264 	unsigned char sum = 0;
265 
266 	if ((t & 0x8080808080808080ULL) ^ 0x80)			/* Sync */
267 		return -1;
268 
269 	while (t) {						/* Sum */
270 		sum += t & 0xf;
271 		t >>= 4;
272 	}
273 
274 	return sum & 0xf;
275 }
276 
277 /*
278  * sw_parse() analyzes SideWinder joystick data, and writes the results into
279  * the axes and buttons arrays.
280  */
281 
282 static int sw_parse(unsigned char *buf, struct sw *sw)
283 {
284 	int hat, i, j;
285 	struct input_dev *dev;
286 
287 	switch (sw->type) {
288 
289 		case SW_ID_3DP:
290 
291 			if (sw_check(GB(0,64)) || (hat = (GB(6,1) << 3) | GB(60,3)) > 8)
292 				return -1;
293 
294 			dev = sw->dev[0];
295 
296 			input_report_abs(dev, ABS_X,        (GB( 3,3) << 7) | GB(16,7));
297 			input_report_abs(dev, ABS_Y,        (GB( 0,3) << 7) | GB(24,7));
298 			input_report_abs(dev, ABS_RZ,       (GB(35,2) << 7) | GB(40,7));
299 			input_report_abs(dev, ABS_THROTTLE, (GB(32,3) << 7) | GB(48,7));
300 
301 			input_report_abs(dev, ABS_HAT0X, sw_hat_to_axis[hat].x);
302 			input_report_abs(dev, ABS_HAT0Y, sw_hat_to_axis[hat].y);
303 
304 			for (j = 0; j < 7; j++)
305 				input_report_key(dev, sw_btn[SW_ID_3DP][j], !GB(j+8,1));
306 
307 			input_report_key(dev, BTN_BASE4, !GB(38,1));
308 			input_report_key(dev, BTN_BASE5, !GB(37,1));
309 
310 			input_sync(dev);
311 
312 			return 0;
313 
314 		case SW_ID_GP:
315 
316 			for (i = 0; i < sw->number; i ++) {
317 
318 				if (sw_parity(GB(i*15,15)))
319 					return -1;
320 
321 				input_report_abs(sw->dev[i], ABS_X, GB(i*15+3,1) - GB(i*15+2,1));
322 				input_report_abs(sw->dev[i], ABS_Y, GB(i*15+0,1) - GB(i*15+1,1));
323 
324 				for (j = 0; j < 10; j++)
325 					input_report_key(sw->dev[i], sw_btn[SW_ID_GP][j], !GB(i*15+j+4,1));
326 
327 				input_sync(sw->dev[i]);
328 			}
329 
330 			return 0;
331 
332 		case SW_ID_PP:
333 		case SW_ID_FFP:
334 
335 			if (!sw_parity(GB(0,48)) || (hat = GB(42,4)) > 8)
336 				return -1;
337 
338 			dev = sw->dev[0];
339 			input_report_abs(dev, ABS_X,        GB( 9,10));
340 			input_report_abs(dev, ABS_Y,        GB(19,10));
341 			input_report_abs(dev, ABS_RZ,       GB(36, 6));
342 			input_report_abs(dev, ABS_THROTTLE, GB(29, 7));
343 
344 			input_report_abs(dev, ABS_HAT0X, sw_hat_to_axis[hat].x);
345 			input_report_abs(dev, ABS_HAT0Y, sw_hat_to_axis[hat].y);
346 
347 			for (j = 0; j < 9; j++)
348 				input_report_key(dev, sw_btn[SW_ID_PP][j], !GB(j,1));
349 
350 			input_sync(dev);
351 
352 			return 0;
353 
354 		case SW_ID_FSP:
355 
356 			if (!sw_parity(GB(0,43)) || (hat = GB(28,4)) > 8)
357 				return -1;
358 
359 			dev = sw->dev[0];
360 			input_report_abs(dev, ABS_X,        GB( 0,10));
361 			input_report_abs(dev, ABS_Y,        GB(16,10));
362 			input_report_abs(dev, ABS_THROTTLE, GB(32, 6));
363 
364 			input_report_abs(dev, ABS_HAT0X, sw_hat_to_axis[hat].x);
365 			input_report_abs(dev, ABS_HAT0Y, sw_hat_to_axis[hat].y);
366 
367 			for (j = 0; j < 6; j++)
368 				input_report_key(dev, sw_btn[SW_ID_FSP][j], !GB(j+10,1));
369 
370 			input_report_key(dev, BTN_TR,     !GB(26,1));
371 			input_report_key(dev, BTN_START,  !GB(27,1));
372 			input_report_key(dev, BTN_MODE,   !GB(38,1));
373 			input_report_key(dev, BTN_SELECT, !GB(39,1));
374 
375 			input_sync(dev);
376 
377 			return 0;
378 
379 		case SW_ID_FFW:
380 
381 			if (!sw_parity(GB(0,33)))
382 				return -1;
383 
384 			dev = sw->dev[0];
385 			input_report_abs(dev, ABS_RX,       GB( 0,10));
386 			input_report_abs(dev, ABS_RUDDER,   GB(10, 6));
387 			input_report_abs(dev, ABS_THROTTLE, GB(16, 6));
388 
389 			for (j = 0; j < 8; j++)
390 				input_report_key(dev, sw_btn[SW_ID_FFW][j], !GB(j+22,1));
391 
392 			input_sync(dev);
393 
394 			return 0;
395 	}
396 
397 	return -1;
398 }
399 
400 /*
401  * sw_read() reads SideWinder joystick data, and reinitializes
402  * the joystick in case of persistent problems. This is the function that is
403  * called from the generic code to poll the joystick.
404  */
405 
406 static int sw_read(struct sw *sw)
407 {
408 	unsigned char buf[SW_LENGTH];
409 	int i;
410 
411 	i = sw_read_packet(sw->gameport, buf, sw->length, 0);
412 
413 	if (sw->type == SW_ID_3DP && sw->length == 66 && i != 66) {		/* Broken packet, try to fix */
414 
415 		if (i == 64 && !sw_check(sw_get_bits(buf,0,64,1))) {		/* Last init failed, 1 bit mode */
416 			printk(KERN_WARNING "sidewinder.c: Joystick in wrong mode on %s"
417 				" - going to reinitialize.\n", sw->gameport->phys);
418 			sw->fail = SW_FAIL;					/* Reinitialize */
419 			i = 128;						/* Bogus value */
420 		}
421 
422 		if (i < 66 && GB(0,64) == GB(i*3-66,64))			/* 1 == 3 */
423 			i = 66;							/* Everything is fine */
424 
425 		if (i < 66 && GB(0,64) == GB(66,64))				/* 1 == 2 */
426 			i = 66;							/* Everything is fine */
427 
428 		if (i < 66 && GB(i*3-132,64) == GB(i*3-66,64)) {		/* 2 == 3 */
429 			memmove(buf, buf + i - 22, 22);				/* Move data */
430 			i = 66;							/* Carry on */
431 		}
432 	}
433 
434 	if (i == sw->length && !sw_parse(buf, sw)) {				/* Parse data */
435 
436 		sw->fail = 0;
437 		sw->ok++;
438 
439 		if (sw->type == SW_ID_3DP && sw->length == 66			/* Many packets OK */
440 			&& sw->ok > SW_OK) {
441 
442 			printk(KERN_INFO "sidewinder.c: No more trouble on %s"
443 				" - enabling optimization again.\n", sw->gameport->phys);
444 			sw->length = 22;
445 		}
446 
447 		return 0;
448 	}
449 
450 	sw->ok = 0;
451 	sw->fail++;
452 
453 	if (sw->type == SW_ID_3DP && sw->length == 22 && sw->fail > SW_BAD) {	/* Consecutive bad packets */
454 
455 		printk(KERN_INFO "sidewinder.c: Many bit errors on %s"
456 			" - disabling optimization.\n", sw->gameport->phys);
457 		sw->length = 66;
458 	}
459 
460 	if (sw->fail < SW_FAIL)
461 		return -1;							/* Not enough, don't reinitialize yet */
462 
463 	printk(KERN_WARNING "sidewinder.c: Too many bit errors on %s"
464 		" - reinitializing joystick.\n", sw->gameport->phys);
465 
466 	if (!i && sw->type == SW_ID_3DP) {					/* 3D Pro can be in analog mode */
467 		mdelay(3 * SW_TIMEOUT);
468 		sw_init_digital(sw->gameport);
469 	}
470 
471 	mdelay(SW_TIMEOUT);
472 	i = sw_read_packet(sw->gameport, buf, SW_LENGTH, 0);			/* Read normal data packet */
473 	mdelay(SW_TIMEOUT);
474 	sw_read_packet(sw->gameport, buf, SW_LENGTH, i);			/* Read ID packet, this initializes the stick */
475 
476 	sw->fail = SW_FAIL;
477 
478 	return -1;
479 }
480 
481 static void sw_poll(struct gameport *gameport)
482 {
483 	struct sw *sw = gameport_get_drvdata(gameport);
484 
485 	sw->reads++;
486 	if (sw_read(sw))
487 		sw->bads++;
488 }
489 
490 static int sw_open(struct input_dev *dev)
491 {
492 	struct sw *sw = input_get_drvdata(dev);
493 
494 	gameport_start_polling(sw->gameport);
495 	return 0;
496 }
497 
498 static void sw_close(struct input_dev *dev)
499 {
500 	struct sw *sw = input_get_drvdata(dev);
501 
502 	gameport_stop_polling(sw->gameport);
503 }
504 
505 /*
506  * sw_print_packet() prints the contents of a SideWinder packet.
507  */
508 
509 static void sw_print_packet(char *name, int length, unsigned char *buf, char bits)
510 {
511 	int i;
512 
513 	printk(KERN_INFO "sidewinder.c: %s packet, %d bits. [", name, length);
514 	for (i = (((length + 3) >> 2) - 1); i >= 0; i--)
515 		printk("%x", (int)sw_get_bits(buf, i << 2, 4, bits));
516 	printk("]\n");
517 }
518 
519 /*
520  * sw_3dp_id() translates the 3DP id into a human legible string.
521  * Unfortunately I don't know how to do this for the other SW types.
522  */
523 
524 static void sw_3dp_id(unsigned char *buf, char *comment, size_t size)
525 {
526 	int i;
527 	char pnp[8], rev[9];
528 
529 	for (i = 0; i < 7; i++)						/* ASCII PnP ID */
530 		pnp[i] = sw_get_bits(buf, 24+8*i, 8, 1);
531 
532 	for (i = 0; i < 8; i++)						/* ASCII firmware revision */
533 		rev[i] = sw_get_bits(buf, 88+8*i, 8, 1);
534 
535 	pnp[7] = rev[8] = 0;
536 
537 	snprintf(comment, size, " [PnP %d.%02d id %s rev %s]",
538 		(int) ((sw_get_bits(buf, 8, 6, 1) << 6) |		/* Two 6-bit values */
539 			sw_get_bits(buf, 16, 6, 1)) / 100,
540 		(int) ((sw_get_bits(buf, 8, 6, 1) << 6) |
541 			sw_get_bits(buf, 16, 6, 1)) % 100,
542 		 pnp, rev);
543 }
544 
545 /*
546  * sw_guess_mode() checks the upper two button bits for toggling -
547  * indication of that the joystick is in 3-bit mode. This is documented
548  * behavior for 3DP ID packet, and for example the FSP does this in
549  * normal packets instead. Fun ...
550  */
551 
552 static int sw_guess_mode(unsigned char *buf, int len)
553 {
554 	int i;
555 	unsigned char xor = 0;
556 
557 	for (i = 1; i < len; i++)
558 		xor |= (buf[i - 1] ^ buf[i]) & 6;
559 
560 	return !!xor * 2 + 1;
561 }
562 
563 /*
564  * sw_connect() probes for SideWinder type joysticks.
565  */
566 
567 static int sw_connect(struct gameport *gameport, struct gameport_driver *drv)
568 {
569 	struct sw *sw;
570 	struct input_dev *input_dev;
571 	int i, j, k, l;
572 	int err = 0;
573 	unsigned char *buf = NULL;	/* [SW_LENGTH] */
574 	unsigned char *idbuf = NULL;	/* [SW_LENGTH] */
575 	unsigned char m = 1;
576 	char comment[40];
577 
578 	comment[0] = 0;
579 
580 	sw = kzalloc(sizeof(struct sw), GFP_KERNEL);
581 	buf = kmalloc(SW_LENGTH, GFP_KERNEL);
582 	idbuf = kmalloc(SW_LENGTH, GFP_KERNEL);
583 	if (!sw || !buf || !idbuf) {
584 		err = -ENOMEM;
585 		goto fail1;
586 	}
587 
588 	sw->gameport = gameport;
589 
590 	gameport_set_drvdata(gameport, sw);
591 
592 	err = gameport_open(gameport, drv, GAMEPORT_MODE_RAW);
593 	if (err)
594 		goto fail1;
595 
596 	dbg("Init 0: Opened %s, io %#x, speed %d",
597 		gameport->phys, gameport->io, gameport->speed);
598 
599 	i = sw_read_packet(gameport, buf, SW_LENGTH, 0);		/* Read normal packet */
600 	msleep(SW_TIMEOUT);
601 	dbg("Init 1: Mode %d. Length %d.", m , i);
602 
603 	if (!i) {							/* No data. 3d Pro analog mode? */
604 		sw_init_digital(gameport);				/* Switch to digital */
605 		msleep(SW_TIMEOUT);
606 		i = sw_read_packet(gameport, buf, SW_LENGTH, 0);	/* Retry reading packet */
607 		msleep(SW_TIMEOUT);
608 		dbg("Init 1b: Length %d.", i);
609 		if (!i) {						/* No data -> FAIL */
610 			err = -ENODEV;
611 			goto fail2;
612 		}
613 	}
614 
615 	j = sw_read_packet(gameport, idbuf, SW_LENGTH, i);		/* Read ID. This initializes the stick */
616 	m |= sw_guess_mode(idbuf, j);					/* ID packet should carry mode info [3DP] */
617 	dbg("Init 2: Mode %d. ID Length %d.", m, j);
618 
619 	if (j <= 0) {							/* Read ID failed. Happens in 1-bit mode on PP */
620 		msleep(SW_TIMEOUT);
621 		i = sw_read_packet(gameport, buf, SW_LENGTH, 0);	/* Retry reading packet */
622 		m |= sw_guess_mode(buf, i);
623 		dbg("Init 2b: Mode %d. Length %d.", m, i);
624 		if (!i) {
625 			err = -ENODEV;
626 			goto fail2;
627 		}
628 		msleep(SW_TIMEOUT);
629 		j = sw_read_packet(gameport, idbuf, SW_LENGTH, i);	/* Retry reading ID */
630 		dbg("Init 2c: ID Length %d.", j);
631 	}
632 
633 	sw->type = -1;
634 	k = SW_FAIL;							/* Try SW_FAIL times */
635 	l = 0;
636 
637 	do {
638 		k--;
639 		msleep(SW_TIMEOUT);
640 		i = sw_read_packet(gameport, buf, SW_LENGTH, 0);	/* Read data packet */
641 		dbg("Init 3: Mode %d. Length %d. Last %d. Tries %d.", m, i, l, k);
642 
643 		if (i > l) {						/* Longer? As we can only lose bits, it makes */
644 									/* no sense to try detection for a packet shorter */
645 			l = i;						/* than the previous one */
646 
647 			sw->number = 1;
648 			sw->gameport = gameport;
649 			sw->length = i;
650 			sw->bits = m;
651 
652 			dbg("Init 3a: Case %d.\n", i * m);
653 
654 			switch (i * m) {
655 				case 60:
656 					sw->number++;
657 					fallthrough;
658 				case 45:				/* Ambiguous packet length */
659 					if (j <= 40) {			/* ID length less or eq 40 -> FSP */
660 					fallthrough;
661 				case 43:
662 						sw->type = SW_ID_FSP;
663 						break;
664 					}
665 					sw->number++;
666 					fallthrough;
667 				case 30:
668 					sw->number++;
669 					fallthrough;
670 				case 15:
671 					sw->type = SW_ID_GP;
672 					break;
673 				case 33:
674 				case 31:
675 					sw->type = SW_ID_FFW;
676 					break;
677 				case 48:				/* Ambiguous */
678 					if (j == 14) {			/* ID length 14*3 -> FFP */
679 						sw->type = SW_ID_FFP;
680 						sprintf(comment, " [AC %s]", sw_get_bits(idbuf,38,1,3) ? "off" : "on");
681 					} else
682 						sw->type = SW_ID_PP;
683 					break;
684 				case 66:
685 					sw->bits = 3;
686 					fallthrough;
687 				case 198:
688 					sw->length = 22;
689 					fallthrough;
690 				case 64:
691 					sw->type = SW_ID_3DP;
692 					if (j == 160)
693 						sw_3dp_id(idbuf, comment, sizeof(comment));
694 					break;
695 			}
696 		}
697 
698 	} while (k && sw->type == -1);
699 
700 	if (sw->type == -1) {
701 		printk(KERN_WARNING "sidewinder.c: unknown joystick device detected "
702 			"on %s, contact <vojtech@ucw.cz>\n", gameport->phys);
703 		sw_print_packet("ID", j * 3, idbuf, 3);
704 		sw_print_packet("Data", i * m, buf, m);
705 		err = -ENODEV;
706 		goto fail2;
707 	}
708 
709 #ifdef SW_DEBUG
710 	sw_print_packet("ID", j * 3, idbuf, 3);
711 	sw_print_packet("Data", i * m, buf, m);
712 #endif
713 
714 	gameport_set_poll_handler(gameport, sw_poll);
715 	gameport_set_poll_interval(gameport, 20);
716 
717 	k = i;
718 	l = j;
719 
720 	for (i = 0; i < sw->number; i++) {
721 		int bits, code;
722 
723 		snprintf(sw->name, sizeof(sw->name),
724 			 "Microsoft SideWinder %s", sw_name[sw->type]);
725 		snprintf(sw->phys[i], sizeof(sw->phys[i]),
726 			 "%s/input%d", gameport->phys, i);
727 
728 		sw->dev[i] = input_dev = input_allocate_device();
729 		if (!input_dev) {
730 			err = -ENOMEM;
731 			goto fail3;
732 		}
733 
734 		input_dev->name = sw->name;
735 		input_dev->phys = sw->phys[i];
736 		input_dev->id.bustype = BUS_GAMEPORT;
737 		input_dev->id.vendor = GAMEPORT_ID_VENDOR_MICROSOFT;
738 		input_dev->id.product = sw->type;
739 		input_dev->id.version = 0x0100;
740 		input_dev->dev.parent = &gameport->dev;
741 
742 		input_set_drvdata(input_dev, sw);
743 
744 		input_dev->open = sw_open;
745 		input_dev->close = sw_close;
746 
747 		input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
748 
749 		for (j = 0; (bits = sw_bit[sw->type][j]); j++) {
750 			int min, max, fuzz, flat;
751 
752 			code = sw_abs[sw->type][j];
753 			min = bits == 1 ? -1 : 0;
754 			max = (1 << bits) - 1;
755 			fuzz = (bits >> 1) >= 2 ? 1 << ((bits >> 1) - 2) : 0;
756 			flat = code == ABS_THROTTLE || bits < 5 ?
757 				0 : 1 << (bits - 5);
758 
759 			input_set_abs_params(input_dev, code,
760 					     min, max, fuzz, flat);
761 		}
762 
763 		for (j = 0; (code = sw_btn[sw->type][j]); j++)
764 			__set_bit(code, input_dev->keybit);
765 
766 		dbg("%s%s [%d-bit id %d data %d]\n", sw->name, comment, m, l, k);
767 
768 		err = input_register_device(sw->dev[i]);
769 		if (err)
770 			goto fail4;
771 	}
772 
773  out:	kfree(buf);
774 	kfree(idbuf);
775 
776 	return err;
777 
778  fail4:	input_free_device(sw->dev[i]);
779  fail3:	while (--i >= 0)
780 		input_unregister_device(sw->dev[i]);
781  fail2:	gameport_close(gameport);
782  fail1:	gameport_set_drvdata(gameport, NULL);
783 	kfree(sw);
784 	goto out;
785 }
786 
787 static void sw_disconnect(struct gameport *gameport)
788 {
789 	struct sw *sw = gameport_get_drvdata(gameport);
790 	int i;
791 
792 	for (i = 0; i < sw->number; i++)
793 		input_unregister_device(sw->dev[i]);
794 	gameport_close(gameport);
795 	gameport_set_drvdata(gameport, NULL);
796 	kfree(sw);
797 }
798 
799 static struct gameport_driver sw_drv = {
800 	.driver		= {
801 		.name	= "sidewinder",
802 		.owner	= THIS_MODULE,
803 	},
804 	.description	= DRIVER_DESC,
805 	.connect	= sw_connect,
806 	.disconnect	= sw_disconnect,
807 };
808 
809 module_gameport_driver(sw_drv);
810