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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Elo serial touchscreen driver
4 *
5 * Copyright (c) 2004 Vojtech Pavlik
6 */
7
8
9/*
10 * This driver can handle serial Elo touchscreens using either the Elo standard
11 * 'E271-2210' 10-byte protocol, Elo legacy 'E281A-4002' 6-byte protocol, Elo
12 * legacy 'E271-140' 4-byte protocol and Elo legacy 'E261-280' 3-byte protocol.
13 */
14
15#include <linux/errno.h>
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/slab.h>
19#include <linux/input.h>
20#include <linux/serio.h>
21#include <linux/ctype.h>
22
23#define DRIVER_DESC "Elo serial touchscreen driver"
24
25MODULE_AUTHOR("Vojtech Pavlik <[email protected]>");
26MODULE_DESCRIPTION(DRIVER_DESC);
27MODULE_LICENSE("GPL");
28
29/*
30 * Definitions & global arrays.
31 */
32
33#define ELO_MAX_LENGTH 10
34
35#define ELO10_PACKET_LEN 8
36#define ELO10_TOUCH 0x03
37#define ELO10_PRESSURE 0x80
38
39#define ELO10_LEAD_BYTE 'U'
40
41#define ELO10_ID_CMD 'i'
42
43#define ELO10_TOUCH_PACKET 'T'
44#define ELO10_ACK_PACKET 'A'
45#define ELI10_ID_PACKET 'I'
46
47/*
48 * Per-touchscreen data.
49 */
50
51struct elo {
52 struct input_dev *dev;
53 struct serio *serio;
54 struct mutex cmd_mutex;
55 struct completion cmd_done;
56 int id;
57 int idx;
58 unsigned char expected_packet;
59 unsigned char csum;
60 unsigned char data[ELO_MAX_LENGTH];
61 unsigned char response[ELO10_PACKET_LEN];
62 char phys[32];
63};
64
65static void elo_process_data_10(struct elo *elo, unsigned char data)
66{
67 struct input_dev *dev = elo->dev;
68
69 elo->data[elo->idx] = data;
70
71 switch (elo->idx++) {
72 case 0:
73 elo->csum = 0xaa;
74 if (data != ELO10_LEAD_BYTE) {
75 dev_dbg(&elo->serio->dev,
76 "unsynchronized data: 0x%02x\n", data);
77 elo->idx = 0;
78 }
79 break;
80
81 case 9:
82 elo->idx = 0;
83 if (data != elo->csum) {
84 dev_dbg(&elo->serio->dev,
85 "bad checksum: 0x%02x, expected 0x%02x\n",
86 data, elo->csum);
87 break;
88 }
89 if (elo->data[1] != elo->expected_packet) {
90 if (elo->data[1] != ELO10_TOUCH_PACKET)
91 dev_dbg(&elo->serio->dev,
92 "unexpected packet: 0x%02x\n",
93 elo->data[1]);
94 break;
95 }
96 if (likely(elo->data[1] == ELO10_TOUCH_PACKET)) {
97 input_report_abs(dev, ABS_X, (elo->data[4] << 8) | elo->data[3]);
98 input_report_abs(dev, ABS_Y, (elo->data[6] << 8) | elo->data[5]);
99 if (elo->data[2] & ELO10_PRESSURE)
100 input_report_abs(dev, ABS_PRESSURE,
101 (elo->data[8] << 8) | elo->data[7]);
102 input_report_key(dev, BTN_TOUCH, elo->data[2] & ELO10_TOUCH);
103 input_sync(dev);
104 } else if (elo->data[1] == ELO10_ACK_PACKET) {
105 if (elo->data[2] == '0')
106 elo->expected_packet = ELO10_TOUCH_PACKET;
107 complete(&elo->cmd_done);
108 } else {
109 memcpy(elo->response, &elo->data[1], ELO10_PACKET_LEN);
110 elo->expected_packet = ELO10_ACK_PACKET;
111 }
112 break;
113 }
114 elo->csum += data;
115}
116
117static void elo_process_data_6(struct elo *elo, unsigned char data)
118{
119 struct input_dev *dev = elo->dev;
120
121 elo->data[elo->idx] = data;
122
123 switch (elo->idx++) {
124
125 case 0:
126 if ((data & 0xc0) != 0xc0)
127 elo->idx = 0;
128 break;
129
130 case 1:
131 if ((data & 0xc0) != 0x80)
132 elo->idx = 0;
133 break;
134
135 case 2:
136 if ((data & 0xc0) != 0x40)
137 elo->idx = 0;
138 break;
139
140 case 3:
141 if (data & 0xc0) {
142 elo->idx = 0;
143 break;
144 }
145
146 input_report_abs(dev, ABS_X, ((elo->data[0] & 0x3f) << 6) | (elo->data[1] & 0x3f));
147 input_report_abs(dev, ABS_Y, ((elo->data[2] & 0x3f) << 6) | (elo->data[3] & 0x3f));
148
149 if (elo->id == 2) {
150 input_report_key(dev, BTN_TOUCH, 1);
151 input_sync(dev);
152 elo->idx = 0;
153 }
154
155 break;
156
157 case 4:
158 if (data) {
159 input_sync(dev);
160 elo->idx = 0;
161 }
162 break;
163
164 case 5:
165 if ((data & 0xf0) == 0) {
166 input_report_abs(dev, ABS_PRESSURE, elo->data[5]);
167 input_report_key(dev, BTN_TOUCH, !!elo->data[5]);
168 }
169 input_sync(dev);
170 elo->idx = 0;
171 break;
172 }
173}
174
175static void elo_process_data_3(struct elo *elo, unsigned char data)
176{
177 struct input_dev *dev = elo->dev;
178
179 elo->data[elo->idx] = data;
180
181 switch (elo->idx++) {
182
183 case 0:
184 if ((data & 0x7f) != 0x01)
185 elo->idx = 0;
186 break;
187 case 2:
188 input_report_key(dev, BTN_TOUCH, !(elo->data[1] & 0x80));
189 input_report_abs(dev, ABS_X, elo->data[1]);
190 input_report_abs(dev, ABS_Y, elo->data[2]);
191 input_sync(dev);
192 elo->idx = 0;
193 break;
194 }
195}
196
197static irqreturn_t elo_interrupt(struct serio *serio,
198 unsigned char data, unsigned int flags)
199{
200 struct elo *elo = serio_get_drvdata(serio);
201
202 switch (elo->id) {
203 case 0:
204 elo_process_data_10(elo, data);
205 break;
206
207 case 1:
208 case 2:
209 elo_process_data_6(elo, data);
210 break;
211
212 case 3:
213 elo_process_data_3(elo, data);
214 break;
215 }
216
217 return IRQ_HANDLED;
218}
219
220static int elo_command_10(struct elo *elo, unsigned char *packet)
221{
222 int error;
223 int i;
224 unsigned char csum = 0xaa + ELO10_LEAD_BYTE;
225
226 guard(mutex)(&elo->cmd_mutex);
227
228 scoped_guard(serio_pause_rx, elo->serio) {
229 elo->expected_packet = toupper(packet[0]);
230 init_completion(&elo->cmd_done);
231 }
232
233 error = serio_write(elo->serio, ELO10_LEAD_BYTE);
234 if (error)
235 return error;
236
237 for (i = 0; i < ELO10_PACKET_LEN; i++) {
238 csum += packet[i];
239 error = serio_write(elo->serio, packet[i]);
240 if (error)
241 return error;
242 }
243
244 error = serio_write(elo->serio, csum);
245 if (error)
246 return error;
247
248 wait_for_completion_timeout(&elo->cmd_done, HZ);
249
250 if (elo->expected_packet != ELO10_TOUCH_PACKET)
251 return -EIO;
252
253 /* We are back in reporting mode, the command was ACKed */
254 memcpy(packet, elo->response, ELO10_PACKET_LEN);
255 return 0;
256}
257
258static int elo_setup_10(struct elo *elo)
259{
260 static const char * const elo_types[] = { "Accu", "Dura", "Intelli", "Carroll" };
261 struct input_dev *dev = elo->dev;
262 unsigned char packet[ELO10_PACKET_LEN] = { ELO10_ID_CMD };
263
264 if (elo_command_10(elo, packet))
265 return -1;
266
267 dev->id.version = (packet[5] << 8) | packet[4];
268
269 input_set_abs_params(dev, ABS_X, 96, 4000, 0, 0);
270 input_set_abs_params(dev, ABS_Y, 96, 4000, 0, 0);
271 if (packet[3] & ELO10_PRESSURE)
272 input_set_abs_params(dev, ABS_PRESSURE, 0, 255, 0, 0);
273
274 dev_info(&elo->serio->dev,
275 "%sTouch touchscreen, fw: %02x.%02x, features: 0x%02x, controller: 0x%02x\n",
276 elo_types[(packet[1] - '0') & 0x03],
277 packet[5], packet[4], packet[3], packet[7]);
278
279 return 0;
280}
281
282/*
283 * elo_disconnect() is the opposite of elo_connect()
284 */
285
286static void elo_disconnect(struct serio *serio)
287{
288 struct elo *elo = serio_get_drvdata(serio);
289
290 input_get_device(elo->dev);
291 input_unregister_device(elo->dev);
292 serio_close(serio);
293 serio_set_drvdata(serio, NULL);
294 input_put_device(elo->dev);
295 kfree(elo);
296}
297
298/*
299 * elo_connect() is the routine that is called when someone adds a
300 * new serio device that supports Gunze protocol and registers it as
301 * an input device.
302 */
303
304static int elo_connect(struct serio *serio, struct serio_driver *drv)
305{
306 struct elo *elo;
307 struct input_dev *input_dev;
308 int err;
309
310 elo = kzalloc_obj(*elo);
311 input_dev = input_allocate_device();
312 if (!elo || !input_dev) {
313 err = -ENOMEM;
314 goto fail1;
315 }
316
317 elo->serio = serio;
318 elo->id = serio->id.id;
319 elo->dev = input_dev;
320 elo->expected_packet = ELO10_TOUCH_PACKET;
321 mutex_init(&elo->cmd_mutex);
322 init_completion(&elo->cmd_done);
323 scnprintf(elo->phys, sizeof(elo->phys), "%s/input0", serio->phys);
324
325 input_dev->name = "Elo Serial TouchScreen";
326 input_dev->phys = elo->phys;
327 input_dev->id.bustype = BUS_RS232;
328 input_dev->id.vendor = SERIO_ELO;
329 input_dev->id.product = elo->id;
330 input_dev->id.version = 0x0100;
331 input_dev->dev.parent = &serio->dev;
332
333 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
334 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
335
336 serio_set_drvdata(serio, elo);
337 err = serio_open(serio, drv);
338 if (err)
339 goto fail2;
340
341 switch (elo->id) {
342
343 case 0: /* 10-byte protocol */
344 if (elo_setup_10(elo)) {
345 err = -EIO;
346 goto fail3;
347 }
348
349 break;
350
351 case 1: /* 6-byte protocol */
352 input_set_abs_params(input_dev, ABS_PRESSURE, 0, 15, 0, 0);
353 fallthrough;
354
355 case 2: /* 4-byte protocol */
356 input_set_abs_params(input_dev, ABS_X, 96, 4000, 0, 0);
357 input_set_abs_params(input_dev, ABS_Y, 96, 4000, 0, 0);
358 break;
359
360 case 3: /* 3-byte protocol */
361 input_set_abs_params(input_dev, ABS_X, 0, 255, 0, 0);
362 input_set_abs_params(input_dev, ABS_Y, 0, 255, 0, 0);
363 break;
364 }
365
366 err = input_register_device(elo->dev);
367 if (err)
368 goto fail3;
369
370 return 0;
371
372 fail3: serio_close(serio);
373 fail2: serio_set_drvdata(serio, NULL);
374 fail1: input_free_device(input_dev);
375 kfree(elo);
376 return err;
377}
378
379/*
380 * The serio driver structure.
381 */
382
383static const struct serio_device_id elo_serio_ids[] = {
384 {
385 .type = SERIO_RS232,
386 .proto = SERIO_ELO,
387 .id = SERIO_ANY,
388 .extra = SERIO_ANY,
389 },
390 { 0 }
391};
392
393MODULE_DEVICE_TABLE(serio, elo_serio_ids);
394
395static struct serio_driver elo_drv = {
396 .driver = {
397 .name = "elo",
398 },
399 .description = DRIVER_DESC,
400 .id_table = elo_serio_ids,
401 .interrupt = elo_interrupt,
402 .connect = elo_connect,
403 .disconnect = elo_disconnect,
404};
405
406module_serio_driver(elo_drv);