xref: /linux/drivers/input/touchscreen/exc3000.c (revision 200323768787a0ee02e01c35c1aff13dc9d77dde) 
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 
43 static const struct i2c_device_id exc3000_id[];
44 
45 struct eeti_dev_info {
46 	const char *name;
47 	int max_xy;
48 };
49 
50 enum eeti_dev_id {
51 	EETI_EXC3000,
52 	EETI_EXC80H60,
53 	EETI_EXC80H84,
54 };
55 
56 static 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 
71 struct 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 
83 static 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 
99 static 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 
107 static inline void exc3000_schedule_timer(struct exc3000_data *data)
108 {
109 	mod_timer(&data->timer, jiffies + msecs_to_jiffies(EXC3000_TIMEOUT_MS));
110 }
111 
112 static void exc3000_shutdown_timer(void *timer)
113 {
114 	timer_shutdown_sync(timer);
115 }
116 
117 static int exc3000_read_frame(struct exc3000_data *data, u8 *buf)
118 {
119 	struct i2c_client *client = data->client;
120 	int ret;
121 
122 	ret = i2c_master_send(client, "'", 2);
123 	if (ret < 0)
124 		return ret;
125 
126 	if (ret != 2)
127 		return -EIO;
128 
129 	ret = i2c_master_recv(client, buf, EXC3000_LEN_FRAME);
130 	if (ret < 0)
131 		return ret;
132 
133 	if (ret != EXC3000_LEN_FRAME)
134 		return -EIO;
135 
136 	if (get_unaligned_le16(buf) != EXC3000_LEN_FRAME)
137 		return -EINVAL;
138 
139 	return 0;
140 }
141 
142 static int exc3000_handle_mt_event(struct exc3000_data *data)
143 {
144 	struct input_dev *input = data->input;
145 	int ret, total_slots;
146 	u8 *buf = data->buf;
147 
148 	total_slots = buf[3];
149 	if (!total_slots || total_slots > EXC3000_NUM_SLOTS) {
150 		ret = -EINVAL;
151 		goto out_fail;
152 	}
153 
154 	if (total_slots > EXC3000_SLOTS_PER_FRAME) {
155 		/* Read 2nd frame to get the rest of the contacts. */
156 		ret = exc3000_read_frame(data, buf + EXC3000_LEN_FRAME);
157 		if (ret)
158 			goto out_fail;
159 
160 		/* 2nd chunk must have number of contacts set to 0. */
161 		if (buf[EXC3000_LEN_FRAME + 3] != 0) {
162 			ret = -EINVAL;
163 			goto out_fail;
164 		}
165 	}
166 
167 	/*
168 	 * We read full state successfully, no contacts will be "stuck".
169 	 */
170 	del_timer_sync(&data->timer);
171 
172 	while (total_slots > 0) {
173 		int slots = min(total_slots, EXC3000_SLOTS_PER_FRAME);
174 
175 		exc3000_report_slots(input, &data->prop, buf + 4, slots);
176 		total_slots -= slots;
177 		buf += EXC3000_LEN_FRAME;
178 	}
179 
180 	input_mt_sync_frame(input);
181 	input_sync(input);
182 
183 	return 0;
184 
185 out_fail:
186 	/* Schedule a timer to release "stuck" contacts */
187 	exc3000_schedule_timer(data);
188 
189 	return ret;
190 }
191 
192 static irqreturn_t exc3000_interrupt(int irq, void *dev_id)
193 {
194 	struct exc3000_data *data = dev_id;
195 	u8 *buf = data->buf;
196 	int ret;
197 
198 	ret = exc3000_read_frame(data, buf);
199 	if (ret) {
200 		/* Schedule a timer to release "stuck" contacts */
201 		exc3000_schedule_timer(data);
202 		goto out;
203 	}
204 
205 	switch (buf[2]) {
206 	case EXC3000_VENDOR_EVENT:
207 		complete(&data->wait_event);
208 		break;
209 
210 	case EXC3000_MT1_EVENT:
211 	case EXC3000_MT2_EVENT:
212 		exc3000_handle_mt_event(data);
213 		break;
214 
215 	default:
216 		break;
217 	}
218 
219 out:
220 	return IRQ_HANDLED;
221 }
222 
223 static int exc3000_vendor_data_request(struct exc3000_data *data, u8 *request,
224 				       u8 request_len, u8 *response, int timeout)
225 {
226 	u8 buf[EXC3000_LEN_VENDOR_REQUEST] = { 0x67, 0x00, 0x42, 0x00, 0x03 };
227 	int ret;
228 	unsigned long time_left;
229 
230 	mutex_lock(&data->query_lock);
231 
232 	reinit_completion(&data->wait_event);
233 
234 	buf[5] = request_len;
235 	memcpy(&buf[6], request, request_len);
236 
237 	ret = i2c_master_send(data->client, buf, EXC3000_LEN_VENDOR_REQUEST);
238 	if (ret < 0)
239 		goto out_unlock;
240 
241 	if (response) {
242 		time_left = wait_for_completion_timeout(&data->wait_event,
243 							timeout * HZ);
244 		if (time_left == 0) {
245 			ret = -ETIMEDOUT;
246 			goto out_unlock;
247 		}
248 
249 		if (data->buf[3] >= EXC3000_LEN_FRAME) {
250 			ret = -ENOSPC;
251 			goto out_unlock;
252 		}
253 
254 		memcpy(response, &data->buf[4], data->buf[3]);
255 		ret = data->buf[3];
256 	}
257 
258 out_unlock:
259 	mutex_unlock(&data->query_lock);
260 
261 	return ret;
262 }
263 
264 static ssize_t fw_version_show(struct device *dev,
265 			       struct device_attribute *attr, char *buf)
266 {
267 	struct i2c_client *client = to_i2c_client(dev);
268 	struct exc3000_data *data = i2c_get_clientdata(client);
269 	u8 response[EXC3000_LEN_FRAME];
270 	int ret;
271 
272 	/* query bootloader info */
273 	ret = exc3000_vendor_data_request(data,
274 					  (u8[]){0x39, 0x02}, 2, response, 1);
275 	if (ret < 0)
276 		return ret;
277 
278 	/*
279 	 * If the bootloader version is non-zero then the device is in
280 	 * bootloader mode and won't answer a query for the application FW
281 	 * version, so we just use the bootloader version info.
282 	 */
283 	if (response[2] || response[3])
284 		return sprintf(buf, "%d.%d\n", response[2], response[3]);
285 
286 	ret = exc3000_vendor_data_request(data, (u8[]){'D'}, 1, response, 1);
287 	if (ret < 0)
288 		return ret;
289 
290 	return sprintf(buf, "%s\n", &response[1]);
291 }
292 static DEVICE_ATTR_RO(fw_version);
293 
294 static ssize_t model_show(struct device *dev,
295 			  struct device_attribute *attr, char *buf)
296 {
297 	struct i2c_client *client = to_i2c_client(dev);
298 	struct exc3000_data *data = i2c_get_clientdata(client);
299 	u8 response[EXC3000_LEN_FRAME];
300 	int ret;
301 
302 	ret = exc3000_vendor_data_request(data, (u8[]){'E'}, 1, response, 1);
303 	if (ret < 0)
304 		return ret;
305 
306 	return sprintf(buf, "%s\n", &response[1]);
307 }
308 static DEVICE_ATTR_RO(model);
309 
310 static ssize_t type_show(struct device *dev,
311 			  struct device_attribute *attr, char *buf)
312 {
313 	struct i2c_client *client = to_i2c_client(dev);
314 	struct exc3000_data *data = i2c_get_clientdata(client);
315 	u8 response[EXC3000_LEN_FRAME];
316 	int ret;
317 
318 	ret = exc3000_vendor_data_request(data, (u8[]){'F'}, 1, response, 1);
319 	if (ret < 0)
320 		return ret;
321 
322 	return sprintf(buf, "%s\n", &response[1]);
323 }
324 static DEVICE_ATTR_RO(type);
325 
326 static struct attribute *sysfs_attrs[] = {
327 	&dev_attr_fw_version.attr,
328 	&dev_attr_model.attr,
329 	&dev_attr_type.attr,
330 	NULL
331 };
332 
333 static struct attribute_group exc3000_attribute_group = {
334 	.attrs = sysfs_attrs
335 };
336 
337 static int exc3000_probe(struct i2c_client *client)
338 {
339 	struct exc3000_data *data;
340 	struct input_dev *input;
341 	int error, max_xy, retry;
342 
343 	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
344 	if (!data)
345 		return -ENOMEM;
346 
347 	data->client = client;
348 	data->info = device_get_match_data(&client->dev);
349 	if (!data->info) {
350 		enum eeti_dev_id eeti_dev_id =
351 			i2c_match_id(exc3000_id, client)->driver_data;
352 		data->info = &exc3000_info[eeti_dev_id];
353 	}
354 	timer_setup(&data->timer, exc3000_timer, 0);
355 	init_completion(&data->wait_event);
356 	mutex_init(&data->query_lock);
357 
358 	data->reset = devm_gpiod_get_optional(&client->dev, "reset",
359 					      GPIOD_OUT_HIGH);
360 	if (IS_ERR(data->reset))
361 		return PTR_ERR(data->reset);
362 
363 	if (data->reset) {
364 		msleep(EXC3000_RESET_MS);
365 		gpiod_set_value_cansleep(data->reset, 0);
366 		msleep(EXC3000_READY_MS);
367 	}
368 
369 	input = devm_input_allocate_device(&client->dev);
370 	if (!input)
371 		return -ENOMEM;
372 
373 	data->input = input;
374 	input_set_drvdata(input, data);
375 
376 	input->name = data->info->name;
377 	input->id.bustype = BUS_I2C;
378 
379 	max_xy = data->info->max_xy;
380 	input_set_abs_params(input, ABS_MT_POSITION_X, 0, max_xy, 0, 0);
381 	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, max_xy, 0, 0);
382 
383 	touchscreen_parse_properties(input, true, &data->prop);
384 
385 	error = input_mt_init_slots(input, EXC3000_NUM_SLOTS,
386 				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
387 	if (error)
388 		return error;
389 
390 	error = input_register_device(input);
391 	if (error)
392 		return error;
393 
394 	error = devm_add_action_or_reset(&client->dev, exc3000_shutdown_timer,
395 					 &data->timer);
396 	if (error)
397 		return error;
398 
399 	error = devm_request_threaded_irq(&client->dev, client->irq,
400 					  NULL, exc3000_interrupt, IRQF_ONESHOT,
401 					  client->name, data);
402 	if (error)
403 		return error;
404 
405 	/*
406 	 * I²C does not have built-in recovery, so retry on failure. This
407 	 * ensures, that the device probe will not fail for temporary issues
408 	 * on the bus.  This is not needed for the sysfs calls (userspace
409 	 * will receive the error code and can start another query) and
410 	 * cannot be done for touch events (but that only means loosing one
411 	 * or two touch events anyways).
412 	 */
413 	for (retry = 0; retry < 3; retry++) {
414 		u8 response[EXC3000_LEN_FRAME];
415 
416 		error = exc3000_vendor_data_request(data, (u8[]){'E'}, 1,
417 						    response, 1);
418 		if (error > 0) {
419 			dev_dbg(&client->dev, "TS Model: %s", &response[1]);
420 			error = 0;
421 			break;
422 		}
423 		dev_warn(&client->dev, "Retry %d get EETI EXC3000 model: %d\n",
424 			 retry + 1, error);
425 	}
426 
427 	if (error)
428 		return error;
429 
430 	i2c_set_clientdata(client, data);
431 
432 	error = devm_device_add_group(&client->dev, &exc3000_attribute_group);
433 	if (error)
434 		return error;
435 
436 	return 0;
437 }
438 
439 static const struct i2c_device_id exc3000_id[] = {
440 	{ "exc3000", EETI_EXC3000 },
441 	{ "exc80h60", EETI_EXC80H60 },
442 	{ "exc80h84", EETI_EXC80H84 },
443 	{ }
444 };
445 MODULE_DEVICE_TABLE(i2c, exc3000_id);
446 
447 #ifdef CONFIG_OF
448 static const struct of_device_id exc3000_of_match[] = {
449 	{ .compatible = "eeti,exc3000", .data = &exc3000_info[EETI_EXC3000] },
450 	{ .compatible = "eeti,exc80h60", .data = &exc3000_info[EETI_EXC80H60] },
451 	{ .compatible = "eeti,exc80h84", .data = &exc3000_info[EETI_EXC80H84] },
452 	{ }
453 };
454 MODULE_DEVICE_TABLE(of, exc3000_of_match);
455 #endif
456 
457 static struct i2c_driver exc3000_driver = {
458 	.driver = {
459 		.name	= "exc3000",
460 		.of_match_table = of_match_ptr(exc3000_of_match),
461 	},
462 	.id_table	= exc3000_id,
463 	.probe_new	= exc3000_probe,
464 };
465 
466 module_i2c_driver(exc3000_driver);
467 
468 MODULE_AUTHOR("Ahmet Inan <inan@distec.de>");
469 MODULE_DESCRIPTION("I2C connected EETI EXC3000 multiple touch controller driver");
470 MODULE_LICENSE("GPL v2");
471