Free Electrons

Embedded Linux Experts

  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
/*
 * Driver for	DEC VSXXX-AA mouse (hockey-puck mouse, ball or two rollers)
 *		DEC VSXXX-GA mouse (rectangular mouse, with ball)
 *		DEC VSXXX-AB tablet (digitizer with hair cross or stylus)
 *
 * Copyright (C) 2003-2004 by Jan-Benedict Glaw <jbglaw@lug-owl.de>
 *
 * The packet format was initially taken from a patch to GPM which is (C) 2001
 * by	Karsten Merker <merker@linuxtag.org>
 * and	Maciej W. Rozycki <macro@ds2.pg.gda.pl>
 * Later on, I had access to the device's documentation (referenced below).
 */

/*
 * 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
 */

/*
 * Building an adaptor to DE9 / DB25 RS232
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 * DISCLAIMER: Use this description AT YOUR OWN RISK! I'll not pay for
 * anything if you break your mouse, your computer or whatever!
 *
 * In theory, this mouse is a simple RS232 device. In practice, it has got
 * a quite uncommon plug and the requirement to additionally get a power
 * supply at +5V and -12V.
 *
 * If you look at the socket/jack (_not_ at the plug), we use this pin
 * numbering:
 *    _______
 *   / 7 6 5 \
 *  | 4 --- 3 |
 *   \  2 1  /
 *    -------
 *
 *	DEC socket	DE9	DB25	Note
 *	1 (GND)		5	7	-
 *	2 (RxD)		2	3	-
 *	3 (TxD)		3	2	-
 *	4 (-12V)	-	-	Somewhere from the PSU. At ATX, it's
 *					the thin blue wire at pin 12 of the
 *					ATX power connector. Only required for
 *					VSXXX-AA/-GA mice.
 *	5 (+5V)		-	-	PSU (red wires of ATX power connector
 *					on pin 4, 6, 19 or 20) or HDD power
 *					connector (also red wire).
 *	6 (+12V)	-	-	HDD power connector, yellow wire. Only
 *					required for VSXXX-AB digitizer.
 *	7 (dev. avail.)	-	-	The mouse shorts this one to pin 1.
 *					This way, the host computer can detect
 *					the mouse. To use it with the adaptor,
 *					simply don't connect this pin.
 *
 * So to get a working adaptor, you need to connect the mouse with three
 * wires to a RS232 port and two or three additional wires for +5V, +12V and
 * -12V to the PSU.
 *
 * Flow specification for the link is 4800, 8o1.
 *
 * The mice and tablet are described in "VCB02 Video Subsystem - Technical
 * Manual", DEC EK-104AA-TM-001. You'll find it at MANX, a search engine
 * specific for DEC documentation. Try
 * http://www.vt100.net/manx/details?pn=EK-104AA-TM-001;id=21;cp=1
 */

#include <linux/delay.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/input.h>
#include <linux/serio.h>
#include <linux/init.h>

#define DRIVER_DESC "Driver for DEC VSXXX-AA and -GA mice and VSXXX-AB tablet"

MODULE_AUTHOR("Jan-Benedict Glaw <jbglaw@lug-owl.de>");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

#undef VSXXXAA_DEBUG
#ifdef VSXXXAA_DEBUG
#define DBG(x...) printk(x)
#else
#define DBG(x...) do {} while (0)
#endif

#define VSXXXAA_INTRO_MASK	0x80
#define VSXXXAA_INTRO_HEAD	0x80
#define IS_HDR_BYTE(x)			\
	(((x) & VSXXXAA_INTRO_MASK) == VSXXXAA_INTRO_HEAD)

#define VSXXXAA_PACKET_MASK	0xe0
#define VSXXXAA_PACKET_REL	0x80
#define VSXXXAA_PACKET_ABS	0xc0
#define VSXXXAA_PACKET_POR	0xa0
#define MATCH_PACKET_TYPE(data, type)	\
	(((data) & VSXXXAA_PACKET_MASK) == (type))



struct vsxxxaa {
	struct input_dev *dev;
	struct serio *serio;
#define BUFLEN 15 /* At least 5 is needed for a full tablet packet */
	unsigned char buf[BUFLEN];
	unsigned char count;
	unsigned char version;
	unsigned char country;
	unsigned char type;
	char name[64];
	char phys[32];
};

static void vsxxxaa_drop_bytes(struct vsxxxaa *mouse, int num)
{
	if (num >= mouse->count) {
		mouse->count = 0;
	} else {
		memmove(mouse->buf, mouse->buf + num - 1, BUFLEN - num);
		mouse->count -= num;
	}
}

static void vsxxxaa_queue_byte(struct vsxxxaa *mouse, unsigned char byte)
{
	if (mouse->count == BUFLEN) {
		printk(KERN_ERR "%s on %s: Dropping a byte of full buffer.\n",
			mouse->name, mouse->phys);
		vsxxxaa_drop_bytes(mouse, 1);
	}

	DBG(KERN_INFO "Queueing byte 0x%02x\n", byte);

	mouse->buf[mouse->count++] = byte;
}

static void vsxxxaa_detection_done(struct vsxxxaa *mouse)
{
	switch (mouse->type) {
	case 0x02:
		strlcpy(mouse->name, "DEC VSXXX-AA/-GA mouse",
			sizeof(mouse->name));
		break;

	case 0x04:
		strlcpy(mouse->name, "DEC VSXXX-AB digitizer",
			sizeof(mouse->name));
		break;

	default:
		snprintf(mouse->name, sizeof(mouse->name),
			 "unknown DEC pointer device (type = 0x%02x)",
			 mouse->type);
		break;
	}

	printk(KERN_INFO
		"Found %s version 0x%02x from country 0x%02x on port %s\n",
		mouse->name, mouse->version, mouse->country, mouse->phys);
}

/*
 * Returns number of bytes to be dropped, 0 if packet is okay.
 */
static int vsxxxaa_check_packet(struct vsxxxaa *mouse, int packet_len)
{
	int i;

	/* First byte must be a header byte */
	if (!IS_HDR_BYTE(mouse->buf[0])) {
		DBG("vsck: len=%d, 1st=0x%02x\n", packet_len, mouse->buf[0]);
		return 1;
	}

	/* Check all following bytes */
	for (i = 1; i < packet_len; i++) {
		if (IS_HDR_BYTE(mouse->buf[i])) {
			printk(KERN_ERR
				"Need to drop %d bytes of a broken packet.\n",
				i - 1);
			DBG(KERN_INFO "check: len=%d, b[%d]=0x%02x\n",
			    packet_len, i, mouse->buf[i]);
			return i - 1;
		}
	}

	return 0;
}

static inline int vsxxxaa_smells_like_packet(struct vsxxxaa *mouse,
					     unsigned char type, size_t len)
{
	return mouse->count >= len && MATCH_PACKET_TYPE(mouse->buf[0], type);
}

static void vsxxxaa_handle_REL_packet(struct vsxxxaa *mouse)
{
	struct input_dev *dev = mouse->dev;
	unsigned char *buf = mouse->buf;
	int left, middle, right;
	int dx, dy;

	/*
	 * Check for normal stream packets. This is three bytes,
	 * with the first byte's 3 MSB set to 100.
	 *
	 * [0]:	1	0	0	SignX	SignY	Left	Middle	Right
	 * [1]: 0	dx	dx	dx	dx	dx	dx	dx
	 * [2]:	0	dy	dy	dy	dy	dy	dy	dy
	 */

	/*
	 * Low 7 bit of byte 1 are abs(dx), bit 7 is
	 * 0, bit 4 of byte 0 is direction.
	 */
	dx = buf[1] & 0x7f;
	dx *= ((buf[0] >> 4) & 0x01) ? 1 : -1;

	/*
	 * Low 7 bit of byte 2 are abs(dy), bit 7 is
	 * 0, bit 3 of byte 0 is direction.
	 */
	dy = buf[2] & 0x7f;
	dy *= ((buf[0] >> 3) & 0x01) ? -1 : 1;

	/*
	 * Get button state. It's the low three bits
	 * (for three buttons) of byte 0.
	 */
	left	= buf[0] & 0x04;
	middle	= buf[0] & 0x02;
	right	= buf[0] & 0x01;

	vsxxxaa_drop_bytes(mouse, 3);

	DBG(KERN_INFO "%s on %s: dx=%d, dy=%d, buttons=%s%s%s\n",
	    mouse->name, mouse->phys, dx, dy,
	    left ? "L" : "l", middle ? "M" : "m", right ? "R" : "r");

	/*
	 * Report what we've found so far...
	 */
	input_report_key(dev, BTN_LEFT, left);
	input_report_key(dev, BTN_MIDDLE, middle);
	input_report_key(dev, BTN_RIGHT, right);
	input_report_key(dev, BTN_TOUCH, 0);
	input_report_rel(dev, REL_X, dx);
	input_report_rel(dev, REL_Y, dy);
	input_sync(dev);
}

static void vsxxxaa_handle_ABS_packet(struct vsxxxaa *mouse)
{
	struct input_dev *dev = mouse->dev;
	unsigned char *buf = mouse->buf;
	int left, middle, right, touch;
	int x, y;

	/*
	 * Tablet position / button packet
	 *
	 * [0]:	1	1	0	B4	B3	B2	B1	Pr
	 * [1]:	0	0	X5	X4	X3	X2	X1	X0
	 * [2]:	0	0	X11	X10	X9	X8	X7	X6
	 * [3]:	0	0	Y5	Y4	Y3	Y2	Y1	Y0
	 * [4]:	0	0	Y11	Y10	Y9	Y8	Y7	Y6
	 */

	/*
	 * Get X/Y position. Y axis needs to be inverted since VSXXX-AB
	 * counts down->top while monitor counts top->bottom.
	 */
	x = ((buf[2] & 0x3f) << 6) | (buf[1] & 0x3f);
	y = ((buf[4] & 0x3f) << 6) | (buf[3] & 0x3f);
	y = 1023 - y;

	/*
	 * Get button state. It's bits <4..1> of byte 0.
	 */
	left	= buf[0] & 0x02;
	middle	= buf[0] & 0x04;
	right	= buf[0] & 0x08;
	touch	= buf[0] & 0x10;

	vsxxxaa_drop_bytes(mouse, 5);

	DBG(KERN_INFO "%s on %s: x=%d, y=%d, buttons=%s%s%s%s\n",
	    mouse->name, mouse->phys, x, y,
	    left ? "L" : "l", middle ? "M" : "m",
	    right ? "R" : "r", touch ? "T" : "t");

	/*
	 * Report what we've found so far...
	 */
	input_report_key(dev, BTN_LEFT, left);
	input_report_key(dev, BTN_MIDDLE, middle);
	input_report_key(dev, BTN_RIGHT, right);
	input_report_key(dev, BTN_TOUCH, touch);
	input_report_abs(dev, ABS_X, x);
	input_report_abs(dev, ABS_Y, y);
	input_sync(dev);
}

static void vsxxxaa_handle_POR_packet(struct vsxxxaa *mouse)
{
	struct input_dev *dev = mouse->dev;
	unsigned char *buf = mouse->buf;
	int left, middle, right;
	unsigned char error;

	/*
	 * Check for Power-On-Reset packets. These are sent out
	 * after plugging the mouse in, or when explicitly
	 * requested by sending 'T'.
	 *
	 * [0]:	1	0	1	0	R3	R2	R1	R0
	 * [1]:	0	M2	M1	M0	D3	D2	D1	D0
	 * [2]:	0	E6	E5	E4	E3	E2	E1	E0
	 * [3]:	0	0	0	0	0	Left	Middle	Right
	 *
	 * M: manufacturer location code
	 * R: revision code
	 * E: Error code. If it's in the range of 0x00..0x1f, only some
	 *    minor problem occured. Errors >= 0x20 are considered bad
	 *    and the device may not work properly...
	 * D: <0010> == mouse, <0100> == tablet
	 */

	mouse->version = buf[0] & 0x0f;
	mouse->country = (buf[1] >> 4) & 0x07;
	mouse->type = buf[1] & 0x0f;
	error = buf[2] & 0x7f;

	/*
	 * Get button state. It's the low three bits
	 * (for three buttons) of byte 0. Maybe even the bit <3>
	 * has some meaning if a tablet is attached.
	 */
	left	= buf[0] & 0x04;
	middle	= buf[0] & 0x02;
	right	= buf[0] & 0x01;

	vsxxxaa_drop_bytes(mouse, 4);
	vsxxxaa_detection_done(mouse);

	if (error <= 0x1f) {
		/* No (serious) error. Report buttons */
		input_report_key(dev, BTN_LEFT, left);
		input_report_key(dev, BTN_MIDDLE, middle);
		input_report_key(dev, BTN_RIGHT, right);
		input_report_key(dev, BTN_TOUCH, 0);
		input_sync(dev);

		if (error != 0)
			printk(KERN_INFO "Your %s on %s reports error=0x%02x\n",
				mouse->name, mouse->phys, error);

	}

	/*
	 * If the mouse was hot-plugged, we need to force differential mode
	 * now... However, give it a second to recover from it's reset.
	 */
	printk(KERN_NOTICE
		"%s on %s: Forcing standard packet format, "
		"incremental streaming mode and 72 samples/sec\n",
		mouse->name, mouse->phys);
	serio_write(mouse->serio, 'S');	/* Standard format */
	mdelay(50);
	serio_write(mouse->serio, 'R');	/* Incremental */
	mdelay(50);
	serio_write(mouse->serio, 'L');	/* 72 samples/sec */
}

static void vsxxxaa_parse_buffer(struct vsxxxaa *mouse)
{
	unsigned char *buf = mouse->buf;
	int stray_bytes;

	/*
	 * Parse buffer to death...
	 */
	do {
		/*
		 * Out of sync? Throw away what we don't understand. Each
		 * packet starts with a byte whose bit 7 is set. Unhandled
		 * packets (ie. which we don't know about or simply b0rk3d
		 * data...) will get shifted out of the buffer after some
		 * activity on the mouse.
		 */
		while (mouse->count > 0 && !IS_HDR_BYTE(buf[0])) {
			printk(KERN_ERR "%s on %s: Dropping a byte to regain "
				"sync with mouse data stream...\n",
				mouse->name, mouse->phys);
			vsxxxaa_drop_bytes(mouse, 1);
		}

		/*
		 * Check for packets we know about.
		 */

		if (vsxxxaa_smells_like_packet(mouse, VSXXXAA_PACKET_REL, 3)) {
			/* Check for broken packet */
			stray_bytes = vsxxxaa_check_packet(mouse, 3);
			if (!stray_bytes)
				vsxxxaa_handle_REL_packet(mouse);

		} else if (vsxxxaa_smells_like_packet(mouse,
						      VSXXXAA_PACKET_ABS, 5)) {
			/* Check for broken packet */
			stray_bytes = vsxxxaa_check_packet(mouse, 5);
			if (!stray_bytes)
				vsxxxaa_handle_ABS_packet(mouse);

		} else if (vsxxxaa_smells_like_packet(mouse,
						      VSXXXAA_PACKET_POR, 4)) {
			/* Check for broken packet */
			stray_bytes = vsxxxaa_check_packet(mouse, 4);
			if (!stray_bytes)
				vsxxxaa_handle_POR_packet(mouse);

		} else {
			break; /* No REL, ABS or POR packet found */
		}

		if (stray_bytes > 0) {
			printk(KERN_ERR "Dropping %d bytes now...\n",
				stray_bytes);
			vsxxxaa_drop_bytes(mouse, stray_bytes);
		}

	} while (1);
}

static irqreturn_t vsxxxaa_interrupt(struct serio *serio,
				     unsigned char data, unsigned int flags)
{
	struct vsxxxaa *mouse = serio_get_drvdata(serio);

	vsxxxaa_queue_byte(mouse, data);
	vsxxxaa_parse_buffer(mouse);

	return IRQ_HANDLED;
}

static void vsxxxaa_disconnect(struct serio *serio)
{
	struct vsxxxaa *mouse = serio_get_drvdata(serio);

	serio_close(serio);
	serio_set_drvdata(serio, NULL);
	input_unregister_device(mouse->dev);
	kfree(mouse);
}

static int vsxxxaa_connect(struct serio *serio, struct serio_driver *drv)
{
	struct vsxxxaa *mouse;
	struct input_dev *input_dev;
	int err = -ENOMEM;

	mouse = kzalloc(sizeof(struct vsxxxaa), GFP_KERNEL);
	input_dev = input_allocate_device();
	if (!mouse || !input_dev)
		goto fail1;

	mouse->dev = input_dev;
	mouse->serio = serio;
	strlcat(mouse->name, "DEC VSXXX-AA/-GA mouse or VSXXX-AB digitizer",
		 sizeof(mouse->name));
	snprintf(mouse->phys, sizeof(mouse->phys), "%s/input0", serio->phys);

	input_dev->name = mouse->name;
	input_dev->phys = mouse->phys;
	input_dev->id.bustype = BUS_RS232;
	input_dev->dev.parent = &serio->dev;

	__set_bit(EV_KEY, input_dev->evbit);		/* We have buttons */
	__set_bit(EV_REL, input_dev->evbit);
	__set_bit(EV_ABS, input_dev->evbit);
	__set_bit(BTN_LEFT, input_dev->keybit);		/* We have 3 buttons */
	__set_bit(BTN_MIDDLE, input_dev->keybit);
	__set_bit(BTN_RIGHT, input_dev->keybit);
	__set_bit(BTN_TOUCH, input_dev->keybit);	/* ...and Tablet */
	__set_bit(REL_X, input_dev->relbit);
	__set_bit(REL_Y, input_dev->relbit);
	input_set_abs_params(input_dev, ABS_X, 0, 1023, 0, 0);
	input_set_abs_params(input_dev, ABS_Y, 0, 1023, 0, 0);

	serio_set_drvdata(serio, mouse);

	err = serio_open(serio, drv);
	if (err)
		goto fail2;

	/*
	 * Request selftest. Standard packet format and differential
	 * mode will be requested after the device ID'ed successfully.
	 */
	serio_write(serio, 'T'); /* Test */

	err = input_register_device(input_dev);
	if (err)
		goto fail3;

	return 0;

 fail3:	serio_close(serio);
 fail2:	serio_set_drvdata(serio, NULL);
 fail1:	input_free_device(input_dev);
	kfree(mouse);
	return err;
}

static struct serio_device_id vsxxaa_serio_ids[] = {
	{
		.type	= SERIO_RS232,
		.proto	= SERIO_VSXXXAA,
		.id	= SERIO_ANY,
		.extra	= SERIO_ANY,
	},
	{ 0 }
};

MODULE_DEVICE_TABLE(serio, vsxxaa_serio_ids);

static struct serio_driver vsxxxaa_drv = {
	.driver		= {
		.name	= "vsxxxaa",
	},
	.description	= DRIVER_DESC,
	.id_table	= vsxxaa_serio_ids,
	.connect	= vsxxxaa_connect,
	.interrupt	= vsxxxaa_interrupt,
	.disconnect	= vsxxxaa_disconnect,
};

static int __init vsxxxaa_init(void)
{
	return serio_register_driver(&vsxxxaa_drv);
}

static void __exit vsxxxaa_exit(void)
{
	serio_unregister_driver(&vsxxxaa_drv);
}

module_init(vsxxxaa_init);
module_exit(vsxxxaa_exit);