1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Wacom protocol 4 serial tablet driver
4  *
5  * Copyright 2014      Hans de Goede <hdegoede@redhat.com>
6  * Copyright 2011-2012 Julian Squires <julian@cipht.net>
7  *
8  * Many thanks to Bill Seremetis, without whom PenPartner support
9  * would not have been possible. Thanks to Patrick Mahoney.
10  *
11  * This driver was developed with reference to much code written by others,
12  * particularly:
13  *  - elo, gunze drivers by Vojtech Pavlik <vojtech@ucw.cz>;
14  *  - wacom_w8001 driver by Jaya Kumar <jayakumar.lkml@gmail.com>;
15  *  - the USB wacom input driver, credited to many people
16  *    (see drivers/input/tablet/wacom.h);
17  *  - new and old versions of linuxwacom / xf86-input-wacom credited to
18  *    Frederic Lepied, France. <Lepied@XFree86.org> and
19  *    Ping Cheng, Wacom. <pingc@wacom.com>;
20  *  - and xf86wacom.c (a presumably ancient version of the linuxwacom code),
21  *    by Frederic Lepied and Raph Levien <raph@gtk.org>.
22  *
23  * To do:
24  *  - support pad buttons; (requires access to a model with pad buttons)
25  *  - support (protocol 4-style) tilt (requires access to a > 1.4 rom model)
26  */
27 
28 /*
29  * Wacom serial protocol 4 documentation taken from linuxwacom-0.9.9 code,
30  * protocol 4 uses 7 or 9 byte of data in the following format:
31  *
32  *	Byte 1
33  *	bit 7  Sync bit always 1
34  *	bit 6  Pointing device detected
35  *	bit 5  Cursor = 0 / Stylus = 1
36  *	bit 4  Reserved
37  *	bit 3  1 if a button on the pointing device has been pressed
38  *	bit 2  P0 (optional)
39  *	bit 1  X15
40  *	bit 0  X14
41  *
42  *	Byte 2
43  *	bit 7  Always 0
44  *	bits 6-0 = X13 - X7
45  *
46  *	Byte 3
47  *	bit 7  Always 0
48  *	bits 6-0 = X6 - X0
49  *
50  *	Byte 4
51  *	bit 7  Always 0
52  *	bit 6  B3
53  *	bit 5  B2
54  *	bit 4  B1
55  *	bit 3  B0
56  *	bit 2  P1 (optional)
57  *	bit 1  Y15
58  *	bit 0  Y14
59  *
60  *	Byte 5
61  *	bit 7  Always 0
62  *	bits 6-0 = Y13 - Y7
63  *
64  *	Byte 6
65  *	bit 7  Always 0
66  *	bits 6-0 = Y6 - Y0
67  *
68  *	Byte 7
69  *	bit 7 Always 0
70  *	bit 6  Sign of pressure data; or wheel-rel for cursor tool
71  *	bit 5  P7; or REL1 for cursor tool
72  *	bit 4  P6; or REL0 for cursor tool
73  *	bit 3  P5
74  *	bit 2  P4
75  *	bit 1  P3
76  *	bit 0  P2
77  *
78  *	byte 8 and 9 are optional and present only
79  *	in tilt mode.
80  *
81  *	Byte 8
82  *	bit 7 Always 0
83  *	bit 6 Sign of tilt X
84  *	bit 5  Xt6
85  *	bit 4  Xt5
86  *	bit 3  Xt4
87  *	bit 2  Xt3
88  *	bit 1  Xt2
89  *	bit 0  Xt1
90  *
91  *	Byte 9
92  *	bit 7 Always 0
93  *	bit 6 Sign of tilt Y
94  *	bit 5  Yt6
95  *	bit 4  Yt5
96  *	bit 3  Yt4
97  *	bit 2  Yt3
98  *	bit 1  Yt2
99  *	bit 0  Yt1
100  */
101 
102 #include <linux/completion.h>
103 #include <linux/init.h>
104 #include <linux/input.h>
105 #include <linux/interrupt.h>
106 #include <linux/kernel.h>
107 #include <linux/module.h>
108 #include <linux/serio.h>
109 #include <linux/slab.h>
110 #include <linux/string.h>
111 
112 MODULE_AUTHOR("Julian Squires <julian@cipht.net>, Hans de Goede <hdegoede@redhat.com>");
113 MODULE_DESCRIPTION("Wacom protocol 4 serial tablet driver");
114 MODULE_LICENSE("GPL");
115 
116 #define REQUEST_MODEL_AND_ROM_VERSION	"~#"
117 #define REQUEST_MAX_COORDINATES		"~C\r"
118 #define REQUEST_CONFIGURATION_STRING	"~R\r"
119 #define REQUEST_RESET_TO_PROTOCOL_IV	"\r#"
120 /*
121  * Note: sending "\r$\r" causes at least the Digitizer II to send
122  * packets in ASCII instead of binary.  "\r#" seems to undo that.
123  */
124 
125 #define COMMAND_START_SENDING_PACKETS		"ST\r"
126 #define COMMAND_STOP_SENDING_PACKETS		"SP\r"
127 #define COMMAND_MULTI_MODE_INPUT		"MU1\r"
128 #define COMMAND_ORIGIN_IN_UPPER_LEFT		"OC1\r"
129 #define COMMAND_ENABLE_ALL_MACRO_BUTTONS	"~M0\r"
130 #define COMMAND_DISABLE_GROUP_1_MACRO_BUTTONS	"~M1\r"
131 #define COMMAND_TRANSMIT_AT_MAX_RATE		"IT0\r"
132 #define COMMAND_DISABLE_INCREMENTAL_MODE	"IN0\r"
133 #define COMMAND_ENABLE_CONTINUOUS_MODE		"SR\r"
134 #define COMMAND_ENABLE_PRESSURE_MODE		"PH1\r"
135 #define COMMAND_Z_FILTER			"ZF1\r"
136 
137 /* Note that this is a protocol 4 packet without tilt information. */
138 #define PACKET_LENGTH		7
139 #define DATA_SIZE		32
140 
141 /* flags */
142 #define F_COVERS_SCREEN		0x01
143 #define F_HAS_STYLUS2		0x02
144 #define F_HAS_SCROLLWHEEL	0x04
145 
146 /* device IDs */
147 #define STYLUS_DEVICE_ID	0x02
148 #define CURSOR_DEVICE_ID	0x06
149 #define ERASER_DEVICE_ID	0x0A
150 
151 enum { STYLUS = 1, ERASER, CURSOR };
152 
153 static const struct {
154 	int device_id;
155 	int input_id;
156 } tools[] = {
157 	{ 0, 0 },
158 	{ STYLUS_DEVICE_ID, BTN_TOOL_PEN },
159 	{ ERASER_DEVICE_ID, BTN_TOOL_RUBBER },
160 	{ CURSOR_DEVICE_ID, BTN_TOOL_MOUSE },
161 };
162 
163 struct wacom {
164 	struct input_dev *dev;
165 	struct completion cmd_done;
166 	int result;
167 	u8 expect;
168 	u8 eraser_mask;
169 	unsigned int extra_z_bits;
170 	unsigned int flags;
171 	unsigned int res_x, res_y;
172 	unsigned int max_x, max_y;
173 	unsigned int tool;
174 	unsigned int idx;
175 	u8 data[DATA_SIZE];
176 	char phys[32];
177 };
178 
179 enum {
180 	MODEL_CINTIQ		= 0x504C, /* PL */
181 	MODEL_CINTIQ2		= 0x4454, /* DT */
182 	MODEL_DIGITIZER_II	= 0x5544, /* UD */
183 	MODEL_GRAPHIRE		= 0x4554, /* ET */
184 	MODEL_PENPARTNER	= 0x4354, /* CT */
185 	MODEL_ARTPAD_II		= 0x4B54, /* KT */
186 };
187 
188 static void wacom_handle_model_response(struct wacom *wacom)
189 {
190 	int major_v, minor_v, r = 0;
191 	char *p;
192 
193 	p = strrchr(wacom->data, 'V');
194 	if (p)
195 		r = sscanf(p + 1, "%u.%u", &major_v, &minor_v);
196 	if (r != 2)
197 		major_v = minor_v = 0;
198 
199 	switch (wacom->data[2] << 8 | wacom->data[3]) {
200 	case MODEL_CINTIQ:	/* UNTESTED */
201 	case MODEL_CINTIQ2:
202 		if ((wacom->data[2] << 8 | wacom->data[3]) == MODEL_CINTIQ) {
203 			wacom->dev->name = "Wacom Cintiq";
204 			wacom->dev->id.version = MODEL_CINTIQ;
205 		} else {
206 			wacom->dev->name = "Wacom Cintiq II";
207 			wacom->dev->id.version = MODEL_CINTIQ2;
208 		}
209 		wacom->res_x = 508;
210 		wacom->res_y = 508;
211 
212 		switch (wacom->data[5] << 8 | wacom->data[6]) {
213 		case 0x3731: /* PL-710 */
214 			wacom->res_x = 2540;
215 			wacom->res_y = 2540;
216 			/* fall through */
217 		case 0x3535: /* PL-550 */
218 		case 0x3830: /* PL-800 */
219 			wacom->extra_z_bits = 2;
220 		}
221 
222 		wacom->flags = F_COVERS_SCREEN;
223 		break;
224 
225 	case MODEL_PENPARTNER:
226 		wacom->dev->name = "Wacom Penpartner";
227 		wacom->dev->id.version = MODEL_PENPARTNER;
228 		wacom->res_x = 1000;
229 		wacom->res_y = 1000;
230 		break;
231 
232 	case MODEL_GRAPHIRE:
233 		wacom->dev->name = "Wacom Graphire";
234 		wacom->dev->id.version = MODEL_GRAPHIRE;
235 		wacom->res_x = 1016;
236 		wacom->res_y = 1016;
237 		wacom->max_x = 5103;
238 		wacom->max_y = 3711;
239 		wacom->extra_z_bits = 2;
240 		wacom->eraser_mask = 0x08;
241 		wacom->flags = F_HAS_STYLUS2 | F_HAS_SCROLLWHEEL;
242 		break;
243 
244 	case MODEL_ARTPAD_II:
245 	case MODEL_DIGITIZER_II:
246 		wacom->dev->name = "Wacom Digitizer II";
247 		wacom->dev->id.version = MODEL_DIGITIZER_II;
248 		if (major_v == 1 && minor_v <= 2)
249 			wacom->extra_z_bits = 0; /* UNTESTED */
250 		break;
251 
252 	default:
253 		dev_err(&wacom->dev->dev, "Unsupported Wacom model %s\n",
254 			wacom->data);
255 		wacom->result = -ENODEV;
256 		return;
257 	}
258 
259 	dev_info(&wacom->dev->dev, "%s tablet, version %u.%u\n",
260 		 wacom->dev->name, major_v, minor_v);
261 }
262 
263 static void wacom_handle_configuration_response(struct wacom *wacom)
264 {
265 	int r, skip;
266 
267 	dev_dbg(&wacom->dev->dev, "Configuration string: %s\n", wacom->data);
268 	r = sscanf(wacom->data, "~R%x,%u,%u,%u,%u", &skip, &skip, &skip,
269 		   &wacom->res_x, &wacom->res_y);
270 	if (r != 5)
271 		dev_warn(&wacom->dev->dev, "could not get resolution\n");
272 }
273 
274 static void wacom_handle_coordinates_response(struct wacom *wacom)
275 {
276 	int r;
277 
278 	dev_dbg(&wacom->dev->dev, "Coordinates string: %s\n", wacom->data);
279 	r = sscanf(wacom->data, "~C%u,%u", &wacom->max_x, &wacom->max_y);
280 	if (r != 2)
281 		dev_warn(&wacom->dev->dev, "could not get max coordinates\n");
282 }
283 
284 static void wacom_handle_response(struct wacom *wacom)
285 {
286 	if (wacom->data[0] != '~' || wacom->data[1] != wacom->expect) {
287 		dev_err(&wacom->dev->dev,
288 			"Wacom got an unexpected response: %s\n", wacom->data);
289 		wacom->result = -EIO;
290 	} else {
291 		wacom->result = 0;
292 
293 		switch (wacom->data[1]) {
294 		case '#':
295 			wacom_handle_model_response(wacom);
296 			break;
297 		case 'R':
298 			wacom_handle_configuration_response(wacom);
299 			break;
300 		case 'C':
301 			wacom_handle_coordinates_response(wacom);
302 			break;
303 		}
304 	}
305 
306 	complete(&wacom->cmd_done);
307 }
308 
309 static void wacom_handle_packet(struct wacom *wacom)
310 {
311 	u8 in_proximity_p, stylus_p, button;
312 	unsigned int tool;
313 	int x, y, z;
314 
315 	in_proximity_p = wacom->data[0] & 0x40;
316 	stylus_p = wacom->data[0] & 0x20;
317 	button = (wacom->data[3] & 0x78) >> 3;
318 	x = (wacom->data[0] & 3) << 14 | wacom->data[1]<<7 | wacom->data[2];
319 	y = (wacom->data[3] & 3) << 14 | wacom->data[4]<<7 | wacom->data[5];
320 
321 	if (in_proximity_p && stylus_p) {
322 		z = wacom->data[6] & 0x7f;
323 		if (wacom->extra_z_bits >= 1)
324 			z = z << 1 | (wacom->data[3] & 0x4) >> 2;
325 		if (wacom->extra_z_bits > 1)
326 			z = z << 1 | (wacom->data[0] & 0x4) >> 2;
327 		z = z ^ (0x40 << wacom->extra_z_bits);
328 	} else {
329 		z = -1;
330 	}
331 
332 	if (stylus_p)
333 		tool = (button & wacom->eraser_mask) ? ERASER : STYLUS;
334 	else
335 		tool = CURSOR;
336 
337 	if (tool != wacom->tool && wacom->tool != 0) {
338 		input_report_key(wacom->dev, tools[wacom->tool].input_id, 0);
339 		input_sync(wacom->dev);
340 	}
341 	wacom->tool = tool;
342 
343 	input_report_key(wacom->dev, tools[tool].input_id, in_proximity_p);
344 	input_report_abs(wacom->dev, ABS_MISC,
345 			 in_proximity_p ? tools[tool].device_id : 0);
346 	input_report_abs(wacom->dev, ABS_X, x);
347 	input_report_abs(wacom->dev, ABS_Y, y);
348 	input_report_abs(wacom->dev, ABS_PRESSURE, z);
349 	if (stylus_p) {
350 		input_report_key(wacom->dev, BTN_TOUCH, button & 1);
351 		input_report_key(wacom->dev, BTN_STYLUS, button & 2);
352 		input_report_key(wacom->dev, BTN_STYLUS2, button & 4);
353 	} else {
354 		input_report_key(wacom->dev, BTN_LEFT, button & 1);
355 		input_report_key(wacom->dev, BTN_RIGHT, button & 2);
356 		input_report_key(wacom->dev, BTN_MIDDLE, button & 4);
357 		/* handle relative wheel for non-stylus device */
358 		z = (wacom->data[6] & 0x30) >> 4;
359 		if (wacom->data[6] & 0x40)
360 			z = -z;
361 		input_report_rel(wacom->dev, REL_WHEEL, z);
362 	}
363 	input_sync(wacom->dev);
364 }
365 
366 static void wacom_clear_data_buf(struct wacom *wacom)
367 {
368 	memset(wacom->data, 0, DATA_SIZE);
369 	wacom->idx = 0;
370 }
371 
372 static irqreturn_t wacom_interrupt(struct serio *serio, unsigned char data,
373 				   unsigned int flags)
374 {
375 	struct wacom *wacom = serio_get_drvdata(serio);
376 
377 	if (data & 0x80)
378 		wacom->idx = 0;
379 
380 	/*
381 	 * We're either expecting a carriage return-terminated ASCII
382 	 * response string, or a seven-byte packet with the MSB set on
383 	 * the first byte.
384 	 *
385 	 * Note however that some tablets (the PenPartner, for
386 	 * example) don't send a carriage return at the end of a
387 	 * command.  We handle these by waiting for timeout.
388 	 */
389 	if (data == '\r' && !(wacom->data[0] & 0x80)) {
390 		wacom_handle_response(wacom);
391 		wacom_clear_data_buf(wacom);
392 		return IRQ_HANDLED;
393 	}
394 
395 	/* Leave place for 0 termination */
396 	if (wacom->idx > (DATA_SIZE - 2)) {
397 		dev_dbg(&wacom->dev->dev,
398 			"throwing away %d bytes of garbage\n", wacom->idx);
399 		wacom_clear_data_buf(wacom);
400 	}
401 	wacom->data[wacom->idx++] = data;
402 
403 	if (wacom->idx == PACKET_LENGTH && (wacom->data[0] & 0x80)) {
404 		wacom_handle_packet(wacom);
405 		wacom_clear_data_buf(wacom);
406 	}
407 
408 	return IRQ_HANDLED;
409 }
410 
411 static void wacom_disconnect(struct serio *serio)
412 {
413 	struct wacom *wacom = serio_get_drvdata(serio);
414 
415 	serio_close(serio);
416 	serio_set_drvdata(serio, NULL);
417 	input_unregister_device(wacom->dev);
418 	kfree(wacom);
419 }
420 
421 static int wacom_send(struct serio *serio, const u8 *command)
422 {
423 	int err = 0;
424 
425 	for (; !err && *command; command++)
426 		err = serio_write(serio, *command);
427 
428 	return err;
429 }
430 
431 static int wacom_send_setup_string(struct wacom *wacom, struct serio *serio)
432 {
433 	const u8 *cmd;
434 
435 	switch (wacom->dev->id.version) {
436 	case MODEL_CINTIQ:	/* UNTESTED */
437 		cmd = COMMAND_ORIGIN_IN_UPPER_LEFT
438 			COMMAND_TRANSMIT_AT_MAX_RATE
439 			COMMAND_ENABLE_CONTINUOUS_MODE
440 			COMMAND_START_SENDING_PACKETS;
441 		break;
442 
443 	case MODEL_PENPARTNER:
444 		cmd = COMMAND_ENABLE_PRESSURE_MODE
445 			COMMAND_START_SENDING_PACKETS;
446 		break;
447 
448 	default:
449 		cmd = COMMAND_MULTI_MODE_INPUT
450 			COMMAND_ORIGIN_IN_UPPER_LEFT
451 			COMMAND_ENABLE_ALL_MACRO_BUTTONS
452 			COMMAND_DISABLE_GROUP_1_MACRO_BUTTONS
453 			COMMAND_TRANSMIT_AT_MAX_RATE
454 			COMMAND_DISABLE_INCREMENTAL_MODE
455 			COMMAND_ENABLE_CONTINUOUS_MODE
456 			COMMAND_Z_FILTER
457 			COMMAND_START_SENDING_PACKETS;
458 		break;
459 	}
460 
461 	return wacom_send(serio, cmd);
462 }
463 
464 static int wacom_send_and_wait(struct wacom *wacom, struct serio *serio,
465 			       const u8 *cmd, const char *desc)
466 {
467 	int err;
468 	unsigned long u;
469 
470 	wacom->expect = cmd[1];
471 	init_completion(&wacom->cmd_done);
472 
473 	err = wacom_send(serio, cmd);
474 	if (err)
475 		return err;
476 
477 	u = wait_for_completion_timeout(&wacom->cmd_done, HZ);
478 	if (u == 0) {
479 		/* Timeout, process what we've received. */
480 		wacom_handle_response(wacom);
481 	}
482 
483 	wacom->expect = 0;
484 	return wacom->result;
485 }
486 
487 static int wacom_setup(struct wacom *wacom, struct serio *serio)
488 {
489 	int err;
490 
491 	/* Note that setting the link speed is the job of inputattach.
492 	 * We assume that reset negotiation has already happened,
493 	 * here. */
494 	err = wacom_send_and_wait(wacom, serio, REQUEST_MODEL_AND_ROM_VERSION,
495 				  "model and version");
496 	if (err)
497 		return err;
498 
499 	if (!(wacom->res_x && wacom->res_y)) {
500 		err = wacom_send_and_wait(wacom, serio,
501 					  REQUEST_CONFIGURATION_STRING,
502 					  "configuration string");
503 		if (err)
504 			return err;
505 	}
506 
507 	if (!(wacom->max_x && wacom->max_y)) {
508 		err = wacom_send_and_wait(wacom, serio,
509 					  REQUEST_MAX_COORDINATES,
510 					  "coordinates string");
511 		if (err)
512 			return err;
513 	}
514 
515 	return wacom_send_setup_string(wacom, serio);
516 }
517 
518 static int wacom_connect(struct serio *serio, struct serio_driver *drv)
519 {
520 	struct wacom *wacom;
521 	struct input_dev *input_dev;
522 	int err = -ENOMEM;
523 
524 	wacom = kzalloc(sizeof(struct wacom), GFP_KERNEL);
525 	input_dev = input_allocate_device();
526 	if (!wacom || !input_dev)
527 		goto free_device;
528 
529 	wacom->dev = input_dev;
530 	wacom->extra_z_bits = 1;
531 	wacom->eraser_mask = 0x04;
532 	wacom->tool = wacom->idx = 0;
533 	snprintf(wacom->phys, sizeof(wacom->phys), "%s/input0", serio->phys);
534 	input_dev->phys = wacom->phys;
535 	input_dev->id.bustype = BUS_RS232;
536 	input_dev->id.vendor  = SERIO_WACOM_IV;
537 	input_dev->id.product = serio->id.extra;
538 	input_dev->dev.parent = &serio->dev;
539 
540 	input_dev->evbit[0] =
541 		BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS) | BIT_MASK(EV_REL);
542 	set_bit(ABS_MISC, input_dev->absbit);
543 	set_bit(BTN_TOOL_PEN, input_dev->keybit);
544 	set_bit(BTN_TOOL_RUBBER, input_dev->keybit);
545 	set_bit(BTN_TOOL_MOUSE, input_dev->keybit);
546 	set_bit(BTN_TOUCH, input_dev->keybit);
547 	set_bit(BTN_STYLUS, input_dev->keybit);
548 	set_bit(BTN_LEFT, input_dev->keybit);
549 	set_bit(BTN_RIGHT, input_dev->keybit);
550 	set_bit(BTN_MIDDLE, input_dev->keybit);
551 
552 	serio_set_drvdata(serio, wacom);
553 
554 	err = serio_open(serio, drv);
555 	if (err)
556 		goto free_device;
557 
558 	err = wacom_setup(wacom, serio);
559 	if (err)
560 		goto close_serio;
561 
562 	set_bit(INPUT_PROP_DIRECT, input_dev->propbit);
563 	if (!(wacom->flags & F_COVERS_SCREEN))
564 		__set_bit(INPUT_PROP_POINTER, input_dev->propbit);
565 
566 	if (wacom->flags & F_HAS_STYLUS2)
567 		__set_bit(BTN_STYLUS2, input_dev->keybit);
568 
569 	if (wacom->flags & F_HAS_SCROLLWHEEL)
570 		__set_bit(REL_WHEEL, input_dev->relbit);
571 
572 	input_abs_set_res(wacom->dev, ABS_X, wacom->res_x);
573 	input_abs_set_res(wacom->dev, ABS_Y, wacom->res_y);
574 	input_set_abs_params(wacom->dev, ABS_X, 0, wacom->max_x, 0, 0);
575 	input_set_abs_params(wacom->dev, ABS_Y, 0, wacom->max_y, 0, 0);
576 	input_set_abs_params(wacom->dev, ABS_PRESSURE, -1,
577 			     (1 << (7 + wacom->extra_z_bits)) - 1, 0, 0);
578 
579 	err = input_register_device(wacom->dev);
580 	if (err)
581 		goto close_serio;
582 
583 	return 0;
584 
585 close_serio:
586 	serio_close(serio);
587 free_device:
588 	serio_set_drvdata(serio, NULL);
589 	input_free_device(input_dev);
590 	kfree(wacom);
591 	return err;
592 }
593 
594 static const struct serio_device_id wacom_serio_ids[] = {
595 	{
596 		.type	= SERIO_RS232,
597 		.proto	= SERIO_WACOM_IV,
598 		.id	= SERIO_ANY,
599 		.extra	= SERIO_ANY,
600 	},
601 	{ 0 }
602 };
603 
604 MODULE_DEVICE_TABLE(serio, wacom_serio_ids);
605 
606 static struct serio_driver wacom_drv = {
607 	.driver		= {
608 		.name	= "wacom_serial4",
609 	},
610 	.description	= "Wacom protocol 4 serial tablet driver",
611 	.id_table	= wacom_serio_ids,
612 	.interrupt	= wacom_interrupt,
613 	.connect	= wacom_connect,
614 	.disconnect	= wacom_disconnect,
615 };
616 
617 module_serio_driver(wacom_drv);
618