1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Driver for	DEC VSXXX-AA mouse (hockey-puck mouse, ball or two rollers)
4 *		DEC VSXXX-GA mouse (rectangular mouse, with ball)
5 *		DEC VSXXX-AB tablet (digitizer with hair cross or stylus)
6 *
7 * Copyright (C) 2003-2004 by Jan-Benedict Glaw <jbglaw@lug-owl.de>
8 *
9 * The packet format was initially taken from a patch to GPM which is (C) 2001
10 * by	Karsten Merker <merker@linuxtag.org>
11 * and	Maciej W. Rozycki <macro@ds2.pg.gda.pl>
12 * Later on, I had access to the device's documentation (referenced below).
13 */
14
15/*
16 * Building an adaptor to DE9 / DB25 RS232
17 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
18 *
19 * DISCLAIMER: Use this description AT YOUR OWN RISK! I'll not pay for
20 * anything if you break your mouse, your computer or whatever!
21 *
22 * In theory, this mouse is a simple RS232 device. In practice, it has got
23 * a quite uncommon plug and the requirement to additionally get a power
24 * supply at +5V and -12V.
25 *
26 * If you look at the socket/jack (_not_ at the plug), we use this pin
27 * numbering:
28 *    _______
29 *   / 7 6 5 \
30 *  | 4 --- 3 |
31 *   \  2 1  /
32 *    -------
33 *
34 *	DEC socket	DE9	DB25	Note
35 *	1 (GND)		5	7	-
36 *	2 (RxD)		2	3	-
37 *	3 (TxD)		3	2	-
38 *	4 (-12V)	-	-	Somewhere from the PSU. At ATX, it's
39 *					the thin blue wire at pin 12 of the
40 *					ATX power connector. Only required for
41 *					VSXXX-AA/-GA mice.
42 *	5 (+5V)		-	-	PSU (red wires of ATX power connector
43 *					on pin 4, 6, 19 or 20) or HDD power
44 *					connector (also red wire).
45 *	6 (+12V)	-	-	HDD power connector, yellow wire. Only
46 *					required for VSXXX-AB digitizer.
47 *	7 (dev. avail.)	-	-	The mouse shorts this one to pin 1.
48 *					This way, the host computer can detect
49 *					the mouse. To use it with the adaptor,
50 *					simply don't connect this pin.
51 *
52 * So to get a working adaptor, you need to connect the mouse with three
53 * wires to a RS232 port and two or three additional wires for +5V, +12V and
54 * -12V to the PSU.
55 *
56 * Flow specification for the link is 4800, 8o1.
57 *
58 * The mice and tablet are described in "VCB02 Video Subsystem - Technical
59 * Manual", DEC EK-104AA-TM-001. You'll find it at MANX, a search engine
60 * specific for DEC documentation. Try
61 * http://www.vt100.net/manx/details?pn=EK-104AA-TM-001;id=21;cp=1
62 */
63
64#include <linux/delay.h>
65#include <linux/module.h>
66#include <linux/slab.h>
67#include <linux/interrupt.h>
68#include <linux/input.h>
69#include <linux/serio.h>
70
71#define DRIVER_DESC "Driver for DEC VSXXX-AA and -GA mice and VSXXX-AB tablet"
72
73MODULE_AUTHOR("Jan-Benedict Glaw <jbglaw@lug-owl.de>");
74MODULE_DESCRIPTION(DRIVER_DESC);
75MODULE_LICENSE("GPL");
76
77#undef VSXXXAA_DEBUG
78#ifdef VSXXXAA_DEBUG
79#define DBG(x...) printk(x)
80#else
81#define DBG(x...) do {} while (0)
82#endif
83
84#define VSXXXAA_INTRO_MASK	0x80
85#define VSXXXAA_INTRO_HEAD	0x80
86#define IS_HDR_BYTE(x)			\
87	(((x) & VSXXXAA_INTRO_MASK) == VSXXXAA_INTRO_HEAD)
88
89#define VSXXXAA_PACKET_MASK	0xe0
90#define VSXXXAA_PACKET_REL	0x80
91#define VSXXXAA_PACKET_ABS	0xc0
92#define VSXXXAA_PACKET_POR	0xa0
93#define MATCH_PACKET_TYPE(data, type)	\
94	(((data) & VSXXXAA_PACKET_MASK) == (type))
95
96
97
98struct vsxxxaa {
99	struct input_dev *dev;
100	struct serio *serio;
101#define BUFLEN 15 /* At least 5 is needed for a full tablet packet */
102	unsigned char buf[BUFLEN];
103	unsigned char count;
104	unsigned char version;
105	unsigned char country;
106	unsigned char type;
107	char name[64];
108	char phys[32];
109};
110
111static void vsxxxaa_drop_bytes(struct vsxxxaa *mouse, int num)
112{
113	if (num >= mouse->count) {
114		mouse->count = 0;
115	} else {
116		memmove(mouse->buf, mouse->buf + num, BUFLEN - num);
117		mouse->count -= num;
118	}
119}
120
121static void vsxxxaa_queue_byte(struct vsxxxaa *mouse, unsigned char byte)
122{
123	if (mouse->count == BUFLEN) {
124		printk(KERN_ERR "%s on %s: Dropping a byte of full buffer.\n",
125			mouse->name, mouse->phys);
126		vsxxxaa_drop_bytes(mouse, 1);
127	}
128
129	DBG(KERN_INFO "Queueing byte 0x%02x\n", byte);
130
131	mouse->buf[mouse->count++] = byte;
132}
133
134static void vsxxxaa_detection_done(struct vsxxxaa *mouse)
135{
136	switch (mouse->type) {
137	case 0x02:
138		strscpy(mouse->name, "DEC VSXXX-AA/-GA mouse",
139			sizeof(mouse->name));
140		break;
141
142	case 0x04:
143		strscpy(mouse->name, "DEC VSXXX-AB digitizer",
144			sizeof(mouse->name));
145		break;
146
147	default:
148		snprintf(mouse->name, sizeof(mouse->name),
149			 "unknown DEC pointer device (type = 0x%02x)",
150			 mouse->type);
151		break;
152	}
153
154	printk(KERN_INFO
155		"Found %s version 0x%02x from country 0x%02x on port %s\n",
156		mouse->name, mouse->version, mouse->country, mouse->phys);
157}
158
159/*
160 * Returns number of bytes to be dropped, 0 if packet is okay.
161 */
162static int vsxxxaa_check_packet(struct vsxxxaa *mouse, int packet_len)
163{
164	int i;
165
166	/* First byte must be a header byte */
167	if (!IS_HDR_BYTE(mouse->buf[0])) {
168		DBG("vsck: len=%d, 1st=0x%02x\n", packet_len, mouse->buf[0]);
169		return 1;
170	}
171
172	/* Check all following bytes */
173	for (i = 1; i < packet_len; i++) {
174		if (IS_HDR_BYTE(mouse->buf[i])) {
175			printk(KERN_ERR
176				"Need to drop %d bytes of a broken packet.\n",
177				i - 1);
178			DBG(KERN_INFO "check: len=%d, b[%d]=0x%02x\n",
179			    packet_len, i, mouse->buf[i]);
180			return i - 1;
181		}
182	}
183
184	return 0;
185}
186
187static inline int vsxxxaa_smells_like_packet(struct vsxxxaa *mouse,
188					     unsigned char type, size_t len)
189{
190	return mouse->count >= len && MATCH_PACKET_TYPE(mouse->buf[0], type);
191}
192
193static void vsxxxaa_handle_REL_packet(struct vsxxxaa *mouse)
194{
195	struct input_dev *dev = mouse->dev;
196	unsigned char *buf = mouse->buf;
197	int left, middle, right;
198	int dx, dy;
199
200	/*
201	 * Check for normal stream packets. This is three bytes,
202	 * with the first byte's 3 MSB set to 100.
203	 *
204	 * [0]:	1	0	0	SignX	SignY	Left	Middle	Right
205	 * [1]: 0	dx	dx	dx	dx	dx	dx	dx
206	 * [2]:	0	dy	dy	dy	dy	dy	dy	dy
207	 */
208
209	/*
210	 * Low 7 bit of byte 1 are abs(dx), bit 7 is
211	 * 0, bit 4 of byte 0 is direction.
212	 */
213	dx = buf[1] & 0x7f;
214	dx *= ((buf[0] >> 4) & 0x01) ? 1 : -1;
215
216	/*
217	 * Low 7 bit of byte 2 are abs(dy), bit 7 is
218	 * 0, bit 3 of byte 0 is direction.
219	 */
220	dy = buf[2] & 0x7f;
221	dy *= ((buf[0] >> 3) & 0x01) ? -1 : 1;
222
223	/*
224	 * Get button state. It's the low three bits
225	 * (for three buttons) of byte 0.
226	 */
227	left	= buf[0] & 0x04;
228	middle	= buf[0] & 0x02;
229	right	= buf[0] & 0x01;
230
231	vsxxxaa_drop_bytes(mouse, 3);
232
233	DBG(KERN_INFO "%s on %s: dx=%d, dy=%d, buttons=%s%s%s\n",
234	    mouse->name, mouse->phys, dx, dy,
235	    left ? "L" : "l", middle ? "M" : "m", right ? "R" : "r");
236
237	/*
238	 * Report what we've found so far...
239	 */
240	input_report_key(dev, BTN_LEFT, left);
241	input_report_key(dev, BTN_MIDDLE, middle);
242	input_report_key(dev, BTN_RIGHT, right);
243	input_report_key(dev, BTN_TOUCH, 0);
244	input_report_rel(dev, REL_X, dx);
245	input_report_rel(dev, REL_Y, dy);
246	input_sync(dev);
247}
248
249static void vsxxxaa_handle_ABS_packet(struct vsxxxaa *mouse)
250{
251	struct input_dev *dev = mouse->dev;
252	unsigned char *buf = mouse->buf;
253	int left, middle, right, touch;
254	int x, y;
255
256	/*
257	 * Tablet position / button packet
258	 *
259	 * [0]:	1	1	0	B4	B3	B2	B1	Pr
260	 * [1]:	0	0	X5	X4	X3	X2	X1	X0
261	 * [2]:	0	0	X11	X10	X9	X8	X7	X6
262	 * [3]:	0	0	Y5	Y4	Y3	Y2	Y1	Y0
263	 * [4]:	0	0	Y11	Y10	Y9	Y8	Y7	Y6
264	 */
265
266	/*
267	 * Get X/Y position. Y axis needs to be inverted since VSXXX-AB
268	 * counts down->top while monitor counts top->bottom.
269	 */
270	x = ((buf[2] & 0x3f) << 6) | (buf[1] & 0x3f);
271	y = ((buf[4] & 0x3f) << 6) | (buf[3] & 0x3f);
272	y = 1023 - y;
273
274	/*
275	 * Get button state. It's bits <4..1> of byte 0.
276	 */
277	left	= buf[0] & 0x02;
278	middle	= buf[0] & 0x04;
279	right	= buf[0] & 0x08;
280	touch	= buf[0] & 0x10;
281
282	vsxxxaa_drop_bytes(mouse, 5);
283
284	DBG(KERN_INFO "%s on %s: x=%d, y=%d, buttons=%s%s%s%s\n",
285	    mouse->name, mouse->phys, x, y,
286	    left ? "L" : "l", middle ? "M" : "m",
287	    right ? "R" : "r", touch ? "T" : "t");
288
289	/*
290	 * Report what we've found so far...
291	 */
292	input_report_key(dev, BTN_LEFT, left);
293	input_report_key(dev, BTN_MIDDLE, middle);
294	input_report_key(dev, BTN_RIGHT, right);
295	input_report_key(dev, BTN_TOUCH, touch);
296	input_report_abs(dev, ABS_X, x);
297	input_report_abs(dev, ABS_Y, y);
298	input_sync(dev);
299}
300
301static void vsxxxaa_handle_POR_packet(struct vsxxxaa *mouse)
302{
303	struct input_dev *dev = mouse->dev;
304	unsigned char *buf = mouse->buf;
305	int left, middle, right;
306	unsigned char error;
307
308	/*
309	 * Check for Power-On-Reset packets. These are sent out
310	 * after plugging the mouse in, or when explicitly
311	 * requested by sending 'T'.
312	 *
313	 * [0]:	1	0	1	0	R3	R2	R1	R0
314	 * [1]:	0	M2	M1	M0	D3	D2	D1	D0
315	 * [2]:	0	E6	E5	E4	E3	E2	E1	E0
316	 * [3]:	0	0	0	0	0	Left	Middle	Right
317	 *
318	 * M: manufacturer location code
319	 * R: revision code
320	 * E: Error code. If it's in the range of 0x00..0x1f, only some
321	 *    minor problem occurred. Errors >= 0x20 are considered bad
322	 *    and the device may not work properly...
323	 * D: <0010> == mouse, <0100> == tablet
324	 */
325
326	mouse->version = buf[0] & 0x0f;
327	mouse->country = (buf[1] >> 4) & 0x07;
328	mouse->type = buf[1] & 0x0f;
329	error = buf[2] & 0x7f;
330
331	/*
332	 * Get button state. It's the low three bits
333	 * (for three buttons) of byte 0. Maybe even the bit <3>
334	 * has some meaning if a tablet is attached.
335	 */
336	left	= buf[0] & 0x04;
337	middle	= buf[0] & 0x02;
338	right	= buf[0] & 0x01;
339
340	vsxxxaa_drop_bytes(mouse, 4);
341	vsxxxaa_detection_done(mouse);
342
343	if (error <= 0x1f) {
344		/* No (serious) error. Report buttons */
345		input_report_key(dev, BTN_LEFT, left);
346		input_report_key(dev, BTN_MIDDLE, middle);
347		input_report_key(dev, BTN_RIGHT, right);
348		input_report_key(dev, BTN_TOUCH, 0);
349		input_sync(dev);
350
351		if (error != 0)
352			printk(KERN_INFO "Your %s on %s reports error=0x%02x\n",
353				mouse->name, mouse->phys, error);
354
355	}
356
357	/*
358	 * If the mouse was hot-plugged, we need to force differential mode
359	 * now... However, give it a second to recover from it's reset.
360	 */
361	printk(KERN_NOTICE
362		"%s on %s: Forcing standard packet format, "
363		"incremental streaming mode and 72 samples/sec\n",
364		mouse->name, mouse->phys);
365	serio_write(mouse->serio, 'S');	/* Standard format */
366	mdelay(50);
367	serio_write(mouse->serio, 'R');	/* Incremental */
368	mdelay(50);
369	serio_write(mouse->serio, 'L');	/* 72 samples/sec */
370}
371
372static void vsxxxaa_parse_buffer(struct vsxxxaa *mouse)
373{
374	unsigned char *buf = mouse->buf;
375	int stray_bytes;
376
377	/*
378	 * Parse buffer to death...
379	 */
380	do {
381		/*
382		 * Out of sync? Throw away what we don't understand. Each
383		 * packet starts with a byte whose bit 7 is set. Unhandled
384		 * packets (ie. which we don't know about or simply b0rk3d
385		 * data...) will get shifted out of the buffer after some
386		 * activity on the mouse.
387		 */
388		while (mouse->count > 0 && !IS_HDR_BYTE(buf[0])) {
389			printk(KERN_ERR "%s on %s: Dropping a byte to regain "
390				"sync with mouse data stream...\n",
391				mouse->name, mouse->phys);
392			vsxxxaa_drop_bytes(mouse, 1);
393		}
394
395		/*
396		 * Check for packets we know about.
397		 */
398
399		if (vsxxxaa_smells_like_packet(mouse, VSXXXAA_PACKET_REL, 3)) {
400			/* Check for broken packet */
401			stray_bytes = vsxxxaa_check_packet(mouse, 3);
402			if (!stray_bytes)
403				vsxxxaa_handle_REL_packet(mouse);
404
405		} else if (vsxxxaa_smells_like_packet(mouse,
406						      VSXXXAA_PACKET_ABS, 5)) {
407			/* Check for broken packet */
408			stray_bytes = vsxxxaa_check_packet(mouse, 5);
409			if (!stray_bytes)
410				vsxxxaa_handle_ABS_packet(mouse);
411
412		} else if (vsxxxaa_smells_like_packet(mouse,
413						      VSXXXAA_PACKET_POR, 4)) {
414			/* Check for broken packet */
415			stray_bytes = vsxxxaa_check_packet(mouse, 4);
416			if (!stray_bytes)
417				vsxxxaa_handle_POR_packet(mouse);
418
419		} else {
420			break; /* No REL, ABS or POR packet found */
421		}
422
423		if (stray_bytes > 0) {
424			printk(KERN_ERR "Dropping %d bytes now...\n",
425				stray_bytes);
426			vsxxxaa_drop_bytes(mouse, stray_bytes);
427		}
428
429	} while (1);
430}
431
432static irqreturn_t vsxxxaa_interrupt(struct serio *serio,
433				     unsigned char data, unsigned int flags)
434{
435	struct vsxxxaa *mouse = serio_get_drvdata(serio);
436
437	vsxxxaa_queue_byte(mouse, data);
438	vsxxxaa_parse_buffer(mouse);
439
440	return IRQ_HANDLED;
441}
442
443static void vsxxxaa_disconnect(struct serio *serio)
444{
445	struct vsxxxaa *mouse = serio_get_drvdata(serio);
446
447	serio_close(serio);
448	serio_set_drvdata(serio, NULL);
449	input_unregister_device(mouse->dev);
450	kfree(mouse);
451}
452
453static int vsxxxaa_connect(struct serio *serio, struct serio_driver *drv)
454{
455	struct vsxxxaa *mouse;
456	struct input_dev *input_dev;
457	int err = -ENOMEM;
458
459	mouse = kzalloc(sizeof(struct vsxxxaa), GFP_KERNEL);
460	input_dev = input_allocate_device();
461	if (!mouse || !input_dev)
462		goto fail1;
463
464	mouse->dev = input_dev;
465	mouse->serio = serio;
466	strlcat(mouse->name, "DEC VSXXX-AA/-GA mouse or VSXXX-AB digitizer",
467		 sizeof(mouse->name));
468	snprintf(mouse->phys, sizeof(mouse->phys), "%s/input0", serio->phys);
469
470	input_dev->name = mouse->name;
471	input_dev->phys = mouse->phys;
472	input_dev->id.bustype = BUS_RS232;
473	input_dev->dev.parent = &serio->dev;
474
475	__set_bit(EV_KEY, input_dev->evbit);		/* We have buttons */
476	__set_bit(EV_REL, input_dev->evbit);
477	__set_bit(EV_ABS, input_dev->evbit);
478	__set_bit(BTN_LEFT, input_dev->keybit);		/* We have 3 buttons */
479	__set_bit(BTN_MIDDLE, input_dev->keybit);
480	__set_bit(BTN_RIGHT, input_dev->keybit);
481	__set_bit(BTN_TOUCH, input_dev->keybit);	/* ...and Tablet */
482	__set_bit(REL_X, input_dev->relbit);
483	__set_bit(REL_Y, input_dev->relbit);
484	input_set_abs_params(input_dev, ABS_X, 0, 1023, 0, 0);
485	input_set_abs_params(input_dev, ABS_Y, 0, 1023, 0, 0);
486
487	serio_set_drvdata(serio, mouse);
488
489	err = serio_open(serio, drv);
490	if (err)
491		goto fail2;
492
493	/*
494	 * Request selftest. Standard packet format and differential
495	 * mode will be requested after the device ID'ed successfully.
496	 */
497	serio_write(serio, 'T'); /* Test */
498
499	err = input_register_device(input_dev);
500	if (err)
501		goto fail3;
502
503	return 0;
504
505 fail3:	serio_close(serio);
506 fail2:	serio_set_drvdata(serio, NULL);
507 fail1:	input_free_device(input_dev);
508	kfree(mouse);
509	return err;
510}
511
512static struct serio_device_id vsxxaa_serio_ids[] = {
513	{
514		.type	= SERIO_RS232,
515		.proto	= SERIO_VSXXXAA,
516		.id	= SERIO_ANY,
517		.extra	= SERIO_ANY,
518	},
519	{ 0 }
520};
521
522MODULE_DEVICE_TABLE(serio, vsxxaa_serio_ids);
523
524static struct serio_driver vsxxxaa_drv = {
525	.driver		= {
526		.name	= "vsxxxaa",
527	},
528	.description	= DRIVER_DESC,
529	.id_table	= vsxxaa_serio_ids,
530	.connect	= vsxxxaa_connect,
531	.interrupt	= vsxxxaa_interrupt,
532	.disconnect	= vsxxxaa_disconnect,
533};
534
535module_serio_driver(vsxxxaa_drv);
536