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
112MODULE_AUTHOR("Julian Squires <julian@cipht.net>, Hans de Goede <hdegoede@redhat.com>");
113MODULE_DESCRIPTION("Wacom protocol 4 serial tablet driver");
114MODULE_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
151enum { STYLUS = 1, ERASER, CURSOR };
152
153static 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
163struct 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
179enum {
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
188static 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			fallthrough;
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
263static 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
274static 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
284static 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
309static 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
366static void wacom_clear_data_buf(struct wacom *wacom)
367{
368	memset(wacom->data, 0, DATA_SIZE);
369	wacom->idx = 0;
370}
371
372static 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
411static 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
421static 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
431static 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
464static 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
487static 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
518static 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
585close_serio:
586	serio_close(serio);
587free_device:
588	serio_set_drvdata(serio, NULL);
589	input_free_device(input_dev);
590	kfree(wacom);
591	return err;
592}
593
594static 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
604MODULE_DEVICE_TABLE(serio, wacom_serio_ids);
605
606static 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
617module_serio_driver(wacom_drv);
618