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/acpi.h>
11 #include <linux/bitops.h>
12 #include <linux/delay.h>
13 #include <linux/device.h>
14 #include <linux/gpio/consumer.h>
15 #include <linux/i2c.h>
16 #include <linux/input.h>
17 #include <linux/input/mt.h>
18 #include <linux/input/touchscreen.h>
19 #include <linux/interrupt.h>
20 #include <linux/module.h>
21 #include <linux/of.h>
22 #include <linux/regulator/consumer.h>
23 #include <linux/sizes.h>
24 #include <linux/timer.h>
25 #include <asm/unaligned.h>
26
27 #define EXC3000_NUM_SLOTS 10
28 #define EXC3000_SLOTS_PER_FRAME 5
29 #define EXC3000_LEN_FRAME 66
30 #define EXC3000_LEN_VENDOR_REQUEST 68
31 #define EXC3000_LEN_POINT 10
32
33 #define EXC3000_LEN_MODEL_NAME 16
34 #define EXC3000_LEN_FW_VERSION 16
35
36 #define EXC3000_VENDOR_EVENT 0x03
37 #define EXC3000_MT1_EVENT 0x06
38 #define EXC3000_MT2_EVENT 0x18
39
40 #define EXC3000_TIMEOUT_MS 100
41
42 #define EXC3000_RESET_MS 10
43 #define EXC3000_READY_MS 100
44
45 static const struct i2c_device_id exc3000_id[];
46
47 struct eeti_dev_info {
48 const char *name;
49 int max_xy;
50 };
51
52 enum eeti_dev_id {
53 EETI_EXC3000,
54 EETI_EXC80H60,
55 EETI_EXC80H84,
56 };
57
58 static struct eeti_dev_info exc3000_info[] = {
59 [EETI_EXC3000] = {
60 .name = "EETI EXC3000 Touch Screen",
61 .max_xy = SZ_4K - 1,
62 },
63 [EETI_EXC80H60] = {
64 .name = "EETI EXC80H60 Touch Screen",
65 .max_xy = SZ_16K - 1,
66 },
67 [EETI_EXC80H84] = {
68 .name = "EETI EXC80H84 Touch Screen",
69 .max_xy = SZ_16K - 1,
70 },
71 };
72
73 struct exc3000_data {
74 struct i2c_client *client;
75 const struct eeti_dev_info *info;
76 struct input_dev *input;
77 struct touchscreen_properties prop;
78 struct gpio_desc *reset;
79 struct timer_list timer;
80 u8 buf[2 * EXC3000_LEN_FRAME];
81 struct completion wait_event;
82 struct mutex query_lock;
83 };
84
exc3000_report_slots(struct input_dev * input,struct touchscreen_properties * prop,const u8 * buf,int num)85 static void exc3000_report_slots(struct input_dev *input,
86 struct touchscreen_properties *prop,
87 const u8 *buf, int num)
88 {
89 for (; num--; buf += EXC3000_LEN_POINT) {
90 if (buf[0] & BIT(0)) {
91 input_mt_slot(input, buf[1]);
92 input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
93 touchscreen_report_pos(input, prop,
94 get_unaligned_le16(buf + 2),
95 get_unaligned_le16(buf + 4),
96 true);
97 }
98 }
99 }
100
exc3000_timer(struct timer_list * t)101 static void exc3000_timer(struct timer_list *t)
102 {
103 struct exc3000_data *data = from_timer(data, t, timer);
104
105 input_mt_sync_frame(data->input);
106 input_sync(data->input);
107 }
108
exc3000_schedule_timer(struct exc3000_data * data)109 static inline void exc3000_schedule_timer(struct exc3000_data *data)
110 {
111 mod_timer(&data->timer, jiffies + msecs_to_jiffies(EXC3000_TIMEOUT_MS));
112 }
113
exc3000_shutdown_timer(void * timer)114 static void exc3000_shutdown_timer(void *timer)
115 {
116 timer_shutdown_sync(timer);
117 }
118
exc3000_read_frame(struct exc3000_data * data,u8 * buf)119 static int exc3000_read_frame(struct exc3000_data *data, u8 *buf)
120 {
121 struct i2c_client *client = data->client;
122 int ret;
123
124 ret = i2c_master_send(client, "'", 2);
125 if (ret < 0)
126 return ret;
127
128 if (ret != 2)
129 return -EIO;
130
131 ret = i2c_master_recv(client, buf, EXC3000_LEN_FRAME);
132 if (ret < 0)
133 return ret;
134
135 if (ret != EXC3000_LEN_FRAME)
136 return -EIO;
137
138 if (get_unaligned_le16(buf) != EXC3000_LEN_FRAME)
139 return -EINVAL;
140
141 return 0;
142 }
143
exc3000_handle_mt_event(struct exc3000_data * data)144 static int exc3000_handle_mt_event(struct exc3000_data *data)
145 {
146 struct input_dev *input = data->input;
147 int ret, total_slots;
148 u8 *buf = data->buf;
149
150 total_slots = buf[3];
151 if (!total_slots || total_slots > EXC3000_NUM_SLOTS) {
152 ret = -EINVAL;
153 goto out_fail;
154 }
155
156 if (total_slots > EXC3000_SLOTS_PER_FRAME) {
157 /* Read 2nd frame to get the rest of the contacts. */
158 ret = exc3000_read_frame(data, buf + EXC3000_LEN_FRAME);
159 if (ret)
160 goto out_fail;
161
162 /* 2nd chunk must have number of contacts set to 0. */
163 if (buf[EXC3000_LEN_FRAME + 3] != 0) {
164 ret = -EINVAL;
165 goto out_fail;
166 }
167 }
168
169 /*
170 * We read full state successfully, no contacts will be "stuck".
171 */
172 del_timer_sync(&data->timer);
173
174 while (total_slots > 0) {
175 int slots = min(total_slots, EXC3000_SLOTS_PER_FRAME);
176
177 exc3000_report_slots(input, &data->prop, buf + 4, slots);
178 total_slots -= slots;
179 buf += EXC3000_LEN_FRAME;
180 }
181
182 input_mt_sync_frame(input);
183 input_sync(input);
184
185 return 0;
186
187 out_fail:
188 /* Schedule a timer to release "stuck" contacts */
189 exc3000_schedule_timer(data);
190
191 return ret;
192 }
193
exc3000_interrupt(int irq,void * dev_id)194 static irqreturn_t exc3000_interrupt(int irq, void *dev_id)
195 {
196 struct exc3000_data *data = dev_id;
197 u8 *buf = data->buf;
198 int ret;
199
200 ret = exc3000_read_frame(data, buf);
201 if (ret) {
202 /* Schedule a timer to release "stuck" contacts */
203 exc3000_schedule_timer(data);
204 goto out;
205 }
206
207 switch (buf[2]) {
208 case EXC3000_VENDOR_EVENT:
209 complete(&data->wait_event);
210 break;
211
212 case EXC3000_MT1_EVENT:
213 case EXC3000_MT2_EVENT:
214 exc3000_handle_mt_event(data);
215 break;
216
217 default:
218 break;
219 }
220
221 out:
222 return IRQ_HANDLED;
223 }
224
exc3000_vendor_data_request(struct exc3000_data * data,u8 * request,u8 request_len,u8 * response,int timeout)225 static int exc3000_vendor_data_request(struct exc3000_data *data, u8 *request,
226 u8 request_len, u8 *response, int timeout)
227 {
228 u8 buf[EXC3000_LEN_VENDOR_REQUEST] = { 0x67, 0x00, 0x42, 0x00, 0x03 };
229 int ret;
230 unsigned long time_left;
231
232 mutex_lock(&data->query_lock);
233
234 reinit_completion(&data->wait_event);
235
236 buf[5] = request_len;
237 memcpy(&buf[6], request, request_len);
238
239 ret = i2c_master_send(data->client, buf, EXC3000_LEN_VENDOR_REQUEST);
240 if (ret < 0)
241 goto out_unlock;
242
243 if (response) {
244 time_left = wait_for_completion_timeout(&data->wait_event,
245 timeout * HZ);
246 if (time_left == 0) {
247 ret = -ETIMEDOUT;
248 goto out_unlock;
249 }
250
251 if (data->buf[3] >= EXC3000_LEN_FRAME) {
252 ret = -ENOSPC;
253 goto out_unlock;
254 }
255
256 memcpy(response, &data->buf[4], data->buf[3]);
257 ret = data->buf[3];
258 }
259
260 out_unlock:
261 mutex_unlock(&data->query_lock);
262
263 return ret;
264 }
265
fw_version_show(struct device * dev,struct device_attribute * attr,char * buf)266 static ssize_t fw_version_show(struct device *dev,
267 struct device_attribute *attr, char *buf)
268 {
269 struct i2c_client *client = to_i2c_client(dev);
270 struct exc3000_data *data = i2c_get_clientdata(client);
271 u8 response[EXC3000_LEN_FRAME];
272 int ret;
273
274 /* query bootloader info */
275 ret = exc3000_vendor_data_request(data,
276 (u8[]){0x39, 0x02}, 2, response, 1);
277 if (ret < 0)
278 return ret;
279
280 /*
281 * If the bootloader version is non-zero then the device is in
282 * bootloader mode and won't answer a query for the application FW
283 * version, so we just use the bootloader version info.
284 */
285 if (response[2] || response[3])
286 return sprintf(buf, "%d.%d\n", response[2], response[3]);
287
288 ret = exc3000_vendor_data_request(data, (u8[]){'D'}, 1, response, 1);
289 if (ret < 0)
290 return ret;
291
292 return sprintf(buf, "%s\n", &response[1]);
293 }
294 static DEVICE_ATTR_RO(fw_version);
295
model_show(struct device * dev,struct device_attribute * attr,char * buf)296 static ssize_t model_show(struct device *dev,
297 struct device_attribute *attr, char *buf)
298 {
299 struct i2c_client *client = to_i2c_client(dev);
300 struct exc3000_data *data = i2c_get_clientdata(client);
301 u8 response[EXC3000_LEN_FRAME];
302 int ret;
303
304 ret = exc3000_vendor_data_request(data, (u8[]){'E'}, 1, response, 1);
305 if (ret < 0)
306 return ret;
307
308 return sprintf(buf, "%s\n", &response[1]);
309 }
310 static DEVICE_ATTR_RO(model);
311
type_show(struct device * dev,struct device_attribute * attr,char * buf)312 static ssize_t type_show(struct device *dev,
313 struct device_attribute *attr, char *buf)
314 {
315 struct i2c_client *client = to_i2c_client(dev);
316 struct exc3000_data *data = i2c_get_clientdata(client);
317 u8 response[EXC3000_LEN_FRAME];
318 int ret;
319
320 ret = exc3000_vendor_data_request(data, (u8[]){'F'}, 1, response, 1);
321 if (ret < 0)
322 return ret;
323
324 return sprintf(buf, "%s\n", &response[1]);
325 }
326 static DEVICE_ATTR_RO(type);
327
328 static struct attribute *sysfs_attrs[] = {
329 &dev_attr_fw_version.attr,
330 &dev_attr_model.attr,
331 &dev_attr_type.attr,
332 NULL
333 };
334
335 static struct attribute_group exc3000_attribute_group = {
336 .attrs = sysfs_attrs
337 };
338
exc3000_probe(struct i2c_client * client)339 static int exc3000_probe(struct i2c_client *client)
340 {
341 struct exc3000_data *data;
342 struct input_dev *input;
343 int error, max_xy, retry;
344
345 data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
346 if (!data)
347 return -ENOMEM;
348
349 data->client = client;
350 data->info = device_get_match_data(&client->dev);
351 if (!data->info) {
352 enum eeti_dev_id eeti_dev_id =
353 i2c_match_id(exc3000_id, client)->driver_data;
354 data->info = &exc3000_info[eeti_dev_id];
355 }
356 timer_setup(&data->timer, exc3000_timer, 0);
357 init_completion(&data->wait_event);
358 mutex_init(&data->query_lock);
359
360 data->reset = devm_gpiod_get_optional(&client->dev, "reset",
361 GPIOD_OUT_HIGH);
362 if (IS_ERR(data->reset))
363 return PTR_ERR(data->reset);
364
365 /* For proper reset sequence, enable power while reset asserted */
366 error = devm_regulator_get_enable(&client->dev, "vdd");
367 if (error && error != -ENODEV)
368 return dev_err_probe(&client->dev, error,
369 "failed to request vdd regulator\n");
370
371 if (data->reset) {
372 msleep(EXC3000_RESET_MS);
373 gpiod_set_value_cansleep(data->reset, 0);
374 msleep(EXC3000_READY_MS);
375 }
376
377 input = devm_input_allocate_device(&client->dev);
378 if (!input)
379 return -ENOMEM;
380
381 data->input = input;
382 input_set_drvdata(input, data);
383
384 input->name = data->info->name;
385 input->id.bustype = BUS_I2C;
386
387 max_xy = data->info->max_xy;
388 input_set_abs_params(input, ABS_MT_POSITION_X, 0, max_xy, 0, 0);
389 input_set_abs_params(input, ABS_MT_POSITION_Y, 0, max_xy, 0, 0);
390
391 touchscreen_parse_properties(input, true, &data->prop);
392
393 error = input_mt_init_slots(input, EXC3000_NUM_SLOTS,
394 INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
395 if (error)
396 return error;
397
398 error = input_register_device(input);
399 if (error)
400 return error;
401
402 error = devm_add_action_or_reset(&client->dev, exc3000_shutdown_timer,
403 &data->timer);
404 if (error)
405 return error;
406
407 error = devm_request_threaded_irq(&client->dev, client->irq,
408 NULL, exc3000_interrupt, IRQF_ONESHOT,
409 client->name, data);
410 if (error)
411 return error;
412
413 /*
414 * I²C does not have built-in recovery, so retry on failure. This
415 * ensures, that the device probe will not fail for temporary issues
416 * on the bus. This is not needed for the sysfs calls (userspace
417 * will receive the error code and can start another query) and
418 * cannot be done for touch events (but that only means loosing one
419 * or two touch events anyways).
420 */
421 for (retry = 0; retry < 3; retry++) {
422 u8 response[EXC3000_LEN_FRAME];
423
424 error = exc3000_vendor_data_request(data, (u8[]){'E'}, 1,
425 response, 1);
426 if (error > 0) {
427 dev_dbg(&client->dev, "TS Model: %s", &response[1]);
428 error = 0;
429 break;
430 }
431 dev_warn(&client->dev, "Retry %d get EETI EXC3000 model: %d\n",
432 retry + 1, error);
433 }
434
435 if (error)
436 return error;
437
438 i2c_set_clientdata(client, data);
439
440 error = devm_device_add_group(&client->dev, &exc3000_attribute_group);
441 if (error)
442 return error;
443
444 return 0;
445 }
446
447 static const struct i2c_device_id exc3000_id[] = {
448 { "exc3000", EETI_EXC3000 },
449 { "exc80h60", EETI_EXC80H60 },
450 { "exc80h84", EETI_EXC80H84 },
451 { }
452 };
453 MODULE_DEVICE_TABLE(i2c, exc3000_id);
454
455 #ifdef CONFIG_OF
456 static const struct of_device_id exc3000_of_match[] = {
457 { .compatible = "eeti,exc3000", .data = &exc3000_info[EETI_EXC3000] },
458 { .compatible = "eeti,exc80h60", .data = &exc3000_info[EETI_EXC80H60] },
459 { .compatible = "eeti,exc80h84", .data = &exc3000_info[EETI_EXC80H84] },
460 { }
461 };
462 MODULE_DEVICE_TABLE(of, exc3000_of_match);
463 #endif
464
465 #ifdef CONFIG_ACPI
466 static const struct acpi_device_id exc3000_acpi_match[] = {
467 { "EGA00001", .driver_data = (kernel_ulong_t)&exc3000_info[EETI_EXC80H60] },
468 { }
469 };
470 MODULE_DEVICE_TABLE(acpi, exc3000_acpi_match);
471 #endif
472
473 static struct i2c_driver exc3000_driver = {
474 .driver = {
475 .name = "exc3000",
476 .of_match_table = of_match_ptr(exc3000_of_match),
477 .acpi_match_table = ACPI_PTR(exc3000_acpi_match),
478 },
479 .id_table = exc3000_id,
480 .probe = exc3000_probe,
481 };
482
483 module_i2c_driver(exc3000_driver);
484
485 MODULE_AUTHOR("Ahmet Inan <inan@distec.de>");
486 MODULE_DESCRIPTION("I2C connected EETI EXC3000 multiple touch controller driver");
487 MODULE_LICENSE("GPL v2");
488