drivers/input/joystick/sidewinder.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  Copyright (c) 1998-2005 Vojtech Pavlik
  */

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

 #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)
 {
 	static const 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(*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++;
 					fallthrough;
 				case 45:				/* Ambiguous packet length */
 					if (j <= 40) {			/* ID length less or eq 40 -> FSP */
 					fallthrough;
 				case 43:
 						sw->type = SW_ID_FSP;
 						break;
 					}
 					sw->number++;
 					fallthrough;
 				case 30:
 					sw->number++;
 					fallthrough;
 				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;
 					fallthrough;
 				case 198:
 					sw->length = 22;
 					fallthrough;
 				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);
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Copyright (c) 1998-2005 Vojtech Pavlik
	*/

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

	#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)
	{
	static const 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(i15+3,1) - GB(i15+2,1));
	input_report_abs(sw->dev[i], ABS_Y, GB(i15+0,1) - GB(i15+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(i3-66,64)) / 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(i3-132,64) == GB(i3-66,64)) { /* 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(*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++;
	fallthrough;
	case 45: /* Ambiguous packet length */
	if (j <= 40) { /* ID length less or eq 40 -> FSP */
	fallthrough;
	case 43:
	sw->type = SW_ID_FSP;
	break;
	}
	sw->number++;
	fallthrough;
	case 30:
	sw->number++;
	fallthrough;
	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 143 -> 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;
	fallthrough;
	case 198:
	sw->length = 22;
	fallthrough;
	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);