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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Driver for I2C connected EETI EXC3000 multiple touch controller
4 *
5 * Copyright (C) 2017 Ahmet Inan <inan@distec.de>
6 *
7 * minimal implementation based on egalax_ts.c and egalax_i2c.c
8 */
9
10#include <linux/bitops.h>
11#include <linux/delay.h>
12#include <linux/device.h>
13#include <linux/gpio/consumer.h>
14#include <linux/i2c.h>
15#include <linux/input.h>
16#include <linux/input/mt.h>
17#include <linux/input/touchscreen.h>
18#include <linux/interrupt.h>
19#include <linux/module.h>
20#include <linux/of.h>
21#include <linux/sizes.h>
22#include <linux/timer.h>
23#include <asm/unaligned.h>
24
25#define EXC3000_NUM_SLOTS 10
26#define EXC3000_SLOTS_PER_FRAME 5
27#define EXC3000_LEN_FRAME 66
28#define EXC3000_LEN_VENDOR_REQUEST 68
29#define EXC3000_LEN_POINT 10
30
31#define EXC3000_LEN_MODEL_NAME 16
32#define EXC3000_LEN_FW_VERSION 16
33
34#define EXC3000_VENDOR_EVENT 0x03
35#define EXC3000_MT1_EVENT 0x06
36#define EXC3000_MT2_EVENT 0x18
37
38#define EXC3000_TIMEOUT_MS 100
39
40#define EXC3000_RESET_MS 10
41#define EXC3000_READY_MS 100
42
43static const struct i2c_device_id exc3000_id[];
44
45struct eeti_dev_info {
46 const char *name;
47 int max_xy;
48};
49
50enum eeti_dev_id {
51 EETI_EXC3000,
52 EETI_EXC80H60,
53 EETI_EXC80H84,
54};
55
56static struct eeti_dev_info exc3000_info[] = {
57 [EETI_EXC3000] = {
58 .name = "EETI EXC3000 Touch Screen",
59 .max_xy = SZ_4K - 1,
60 },
61 [EETI_EXC80H60] = {
62 .name = "EETI EXC80H60 Touch Screen",
63 .max_xy = SZ_16K - 1,
64 },
65 [EETI_EXC80H84] = {
66 .name = "EETI EXC80H84 Touch Screen",
67 .max_xy = SZ_16K - 1,
68 },
69};
70
71struct exc3000_data {
72 struct i2c_client *client;
73 const struct eeti_dev_info *info;
74 struct input_dev *input;
75 struct touchscreen_properties prop;
76 struct gpio_desc *reset;
77 struct timer_list timer;
78 u8 buf[2 * EXC3000_LEN_FRAME];
79 struct completion wait_event;
80 struct mutex query_lock;
81};
82
83static void exc3000_report_slots(struct input_dev *input,
84 struct touchscreen_properties *prop,
85 const u8 *buf, int num)
86{
87 for (; num--; buf += EXC3000_LEN_POINT) {
88 if (buf[0] & BIT(0)) {
89 input_mt_slot(input, buf[1]);
90 input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
91 touchscreen_report_pos(input, prop,
92 get_unaligned_le16(buf + 2),
93 get_unaligned_le16(buf + 4),
94 true);
95 }
96 }
97}
98
99static void exc3000_timer(struct timer_list *t)
100{
101 struct exc3000_data *data = from_timer(data, t, timer);
102
103 input_mt_sync_frame(data->input);
104 input_sync(data->input);
105}
106
107static inline void exc3000_schedule_timer(struct exc3000_data *data)
108{
109 mod_timer(&data->timer, jiffies + msecs_to_jiffies(EXC3000_TIMEOUT_MS));
110}
111
112static int exc3000_read_frame(struct exc3000_data *data, u8 *buf)
113{
114 struct i2c_client *client = data->client;
115 int ret;
116
117 ret = i2c_master_send(client, "'", 2);
118 if (ret < 0)
119 return ret;
120
121 if (ret != 2)
122 return -EIO;
123
124 ret = i2c_master_recv(client, buf, EXC3000_LEN_FRAME);
125 if (ret < 0)
126 return ret;
127
128 if (ret != EXC3000_LEN_FRAME)
129 return -EIO;
130
131 if (get_unaligned_le16(buf) != EXC3000_LEN_FRAME)
132 return -EINVAL;
133
134 return 0;
135}
136
137static int exc3000_handle_mt_event(struct exc3000_data *data)
138{
139 struct input_dev *input = data->input;
140 int ret, total_slots;
141 u8 *buf = data->buf;
142
143 total_slots = buf[3];
144 if (!total_slots || total_slots > EXC3000_NUM_SLOTS) {
145 ret = -EINVAL;
146 goto out_fail;
147 }
148
149 if (total_slots > EXC3000_SLOTS_PER_FRAME) {
150 /* Read 2nd frame to get the rest of the contacts. */
151 ret = exc3000_read_frame(data, buf + EXC3000_LEN_FRAME);
152 if (ret)
153 goto out_fail;
154
155 /* 2nd chunk must have number of contacts set to 0. */
156 if (buf[EXC3000_LEN_FRAME + 3] != 0) {
157 ret = -EINVAL;
158 goto out_fail;
159 }
160 }
161
162 /*
163 * We read full state successfully, no contacts will be "stuck".
164 */
165 del_timer_sync(&data->timer);
166
167 while (total_slots > 0) {
168 int slots = min(total_slots, EXC3000_SLOTS_PER_FRAME);
169
170 exc3000_report_slots(input, &data->prop, buf + 4, slots);
171 total_slots -= slots;
172 buf += EXC3000_LEN_FRAME;
173 }
174
175 input_mt_sync_frame(input);
176 input_sync(input);
177
178 return 0;
179
180out_fail:
181 /* Schedule a timer to release "stuck" contacts */
182 exc3000_schedule_timer(data);
183
184 return ret;
185}
186
187static irqreturn_t exc3000_interrupt(int irq, void *dev_id)
188{
189 struct exc3000_data *data = dev_id;
190 u8 *buf = data->buf;
191 int ret;
192
193 ret = exc3000_read_frame(data, buf);
194 if (ret) {
195 /* Schedule a timer to release "stuck" contacts */
196 exc3000_schedule_timer(data);
197 goto out;
198 }
199
200 switch (buf[2]) {
201 case EXC3000_VENDOR_EVENT:
202 complete(&data->wait_event);
203 break;
204
205 case EXC3000_MT1_EVENT:
206 case EXC3000_MT2_EVENT:
207 exc3000_handle_mt_event(data);
208 break;
209
210 default:
211 break;
212 }
213
214out:
215 return IRQ_HANDLED;
216}
217
218static int exc3000_vendor_data_request(struct exc3000_data *data, u8 *request,
219 u8 request_len, u8 *response, int timeout)
220{
221 u8 buf[EXC3000_LEN_VENDOR_REQUEST] = { 0x67, 0x00, 0x42, 0x00, 0x03 };
222 int ret;
223
224 mutex_lock(&data->query_lock);
225
226 reinit_completion(&data->wait_event);
227
228 buf[5] = request_len;
229 memcpy(&buf[6], request, request_len);
230
231 ret = i2c_master_send(data->client, buf, EXC3000_LEN_VENDOR_REQUEST);
232 if (ret < 0)
233 goto out_unlock;
234
235 if (response) {
236 ret = wait_for_completion_timeout(&data->wait_event,
237 timeout * HZ);
238 if (ret <= 0) {
239 ret = -ETIMEDOUT;
240 goto out_unlock;
241 }
242
243 if (data->buf[3] >= EXC3000_LEN_FRAME) {
244 ret = -ENOSPC;
245 goto out_unlock;
246 }
247
248 memcpy(response, &data->buf[4], data->buf[3]);
249 ret = data->buf[3];
250 }
251
252out_unlock:
253 mutex_unlock(&data->query_lock);
254
255 return ret;
256}
257
258static ssize_t fw_version_show(struct device *dev,
259 struct device_attribute *attr, char *buf)
260{
261 struct i2c_client *client = to_i2c_client(dev);
262 struct exc3000_data *data = i2c_get_clientdata(client);
263 u8 response[EXC3000_LEN_FRAME];
264 int ret;
265
266 /* query bootloader info */
267 ret = exc3000_vendor_data_request(data,
268 (u8[]){0x39, 0x02}, 2, response, 1);
269 if (ret < 0)
270 return ret;
271
272 /*
273 * If the bootloader version is non-zero then the device is in
274 * bootloader mode and won't answer a query for the application FW
275 * version, so we just use the bootloader version info.
276 */
277 if (response[2] || response[3])
278 return sprintf(buf, "%d.%d\n", response[2], response[3]);
279
280 ret = exc3000_vendor_data_request(data, (u8[]){'D'}, 1, response, 1);
281 if (ret < 0)
282 return ret;
283
284 return sprintf(buf, "%s\n", &response[1]);
285}
286static DEVICE_ATTR_RO(fw_version);
287
288static ssize_t model_show(struct device *dev,
289 struct device_attribute *attr, char *buf)
290{
291 struct i2c_client *client = to_i2c_client(dev);
292 struct exc3000_data *data = i2c_get_clientdata(client);
293 u8 response[EXC3000_LEN_FRAME];
294 int ret;
295
296 ret = exc3000_vendor_data_request(data, (u8[]){'E'}, 1, response, 1);
297 if (ret < 0)
298 return ret;
299
300 return sprintf(buf, "%s\n", &response[1]);
301}
302static DEVICE_ATTR_RO(model);
303
304static ssize_t type_show(struct device *dev,
305 struct device_attribute *attr, char *buf)
306{
307 struct i2c_client *client = to_i2c_client(dev);
308 struct exc3000_data *data = i2c_get_clientdata(client);
309 u8 response[EXC3000_LEN_FRAME];
310 int ret;
311
312 ret = exc3000_vendor_data_request(data, (u8[]){'F'}, 1, response, 1);
313 if (ret < 0)
314 return ret;
315
316 return sprintf(buf, "%s\n", &response[1]);
317}
318static DEVICE_ATTR_RO(type);
319
320static struct attribute *sysfs_attrs[] = {
321 &dev_attr_fw_version.attr,
322 &dev_attr_model.attr,
323 &dev_attr_type.attr,
324 NULL
325};
326
327static struct attribute_group exc3000_attribute_group = {
328 .attrs = sysfs_attrs
329};
330
331static int exc3000_probe(struct i2c_client *client)
332{
333 struct exc3000_data *data;
334 struct input_dev *input;
335 int error, max_xy, retry;
336
337 data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
338 if (!data)
339 return -ENOMEM;
340
341 data->client = client;
342 data->info = device_get_match_data(&client->dev);
343 if (!data->info) {
344 enum eeti_dev_id eeti_dev_id =
345 i2c_match_id(exc3000_id, client)->driver_data;
346 data->info = &exc3000_info[eeti_dev_id];
347 }
348 timer_setup(&data->timer, exc3000_timer, 0);
349 init_completion(&data->wait_event);
350 mutex_init(&data->query_lock);
351
352 data->reset = devm_gpiod_get_optional(&client->dev, "reset",
353 GPIOD_OUT_HIGH);
354 if (IS_ERR(data->reset))
355 return PTR_ERR(data->reset);
356
357 if (data->reset) {
358 msleep(EXC3000_RESET_MS);
359 gpiod_set_value_cansleep(data->reset, 0);
360 msleep(EXC3000_READY_MS);
361 }
362
363 input = devm_input_allocate_device(&client->dev);
364 if (!input)
365 return -ENOMEM;
366
367 data->input = input;
368 input_set_drvdata(input, data);
369
370 input->name = data->info->name;
371 input->id.bustype = BUS_I2C;
372
373 max_xy = data->info->max_xy;
374 input_set_abs_params(input, ABS_MT_POSITION_X, 0, max_xy, 0, 0);
375 input_set_abs_params(input, ABS_MT_POSITION_Y, 0, max_xy, 0, 0);
376
377 touchscreen_parse_properties(input, true, &data->prop);
378
379 error = input_mt_init_slots(input, EXC3000_NUM_SLOTS,
380 INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
381 if (error)
382 return error;
383
384 error = input_register_device(input);
385 if (error)
386 return error;
387
388 error = devm_request_threaded_irq(&client->dev, client->irq,
389 NULL, exc3000_interrupt, IRQF_ONESHOT,
390 client->name, data);
391 if (error)
392 return error;
393
394 /*
395 * I²C does not have built-in recovery, so retry on failure. This
396 * ensures, that the device probe will not fail for temporary issues
397 * on the bus. This is not needed for the sysfs calls (userspace
398 * will receive the error code and can start another query) and
399 * cannot be done for touch events (but that only means loosing one
400 * or two touch events anyways).
401 */
402 for (retry = 0; retry < 3; retry++) {
403 u8 response[EXC3000_LEN_FRAME];
404
405 error = exc3000_vendor_data_request(data, (u8[]){'E'}, 1,
406 response, 1);
407 if (error > 0) {
408 dev_dbg(&client->dev, "TS Model: %s", &response[1]);
409 error = 0;
410 break;
411 }
412 dev_warn(&client->dev, "Retry %d get EETI EXC3000 model: %d\n",
413 retry + 1, error);
414 }
415
416 if (error)
417 return error;
418
419 i2c_set_clientdata(client, data);
420
421 error = devm_device_add_group(&client->dev, &exc3000_attribute_group);
422 if (error)
423 return error;
424
425 return 0;
426}
427
428static const struct i2c_device_id exc3000_id[] = {
429 { "exc3000", EETI_EXC3000 },
430 { "exc80h60", EETI_EXC80H60 },
431 { "exc80h84", EETI_EXC80H84 },
432 { }
433};
434MODULE_DEVICE_TABLE(i2c, exc3000_id);
435
436#ifdef CONFIG_OF
437static const struct of_device_id exc3000_of_match[] = {
438 { .compatible = "eeti,exc3000", .data = &exc3000_info[EETI_EXC3000] },
439 { .compatible = "eeti,exc80h60", .data = &exc3000_info[EETI_EXC80H60] },
440 { .compatible = "eeti,exc80h84", .data = &exc3000_info[EETI_EXC80H84] },
441 { }
442};
443MODULE_DEVICE_TABLE(of, exc3000_of_match);
444#endif
445
446static struct i2c_driver exc3000_driver = {
447 .driver = {
448 .name = "exc3000",
449 .of_match_table = of_match_ptr(exc3000_of_match),
450 },
451 .id_table = exc3000_id,
452 .probe_new = exc3000_probe,
453};
454
455module_i2c_driver(exc3000_driver);
456
457MODULE_AUTHOR("Ahmet Inan <inan@distec.de>");
458MODULE_DESCRIPTION("I2C connected EETI EXC3000 multiple touch controller driver");
459MODULE_LICENSE("GPL v2");