xref: /linux/drivers/input/touchscreen/exc3000.c (revision a4eb44a6435d6d8f9e642407a4a06f65eb90ca04) 
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 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 
137 static 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 
180 out_fail:
181 	/* Schedule a timer to release "stuck" contacts */
182 	exc3000_schedule_timer(data);
183 
184 	return ret;
185 }
186 
187 static 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 
214 out:
215 	return IRQ_HANDLED;
216 }
217 
218 static 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 
252 out_unlock:
253 	mutex_unlock(&data->query_lock);
254 
255 	return ret;
256 }
257 
258 static 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 }
286 static DEVICE_ATTR_RO(fw_version);
287 
288 static 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 }
302 static DEVICE_ATTR_RO(model);
303 
304 static 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 }
318 static DEVICE_ATTR_RO(type);
319 
320 static struct attribute *sysfs_attrs[] = {
321 	&dev_attr_fw_version.attr,
322 	&dev_attr_model.attr,
323 	&dev_attr_type.attr,
324 	NULL
325 };
326 
327 static struct attribute_group exc3000_attribute_group = {
328 	.attrs = sysfs_attrs
329 };
330 
331 static 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 
428 static const struct i2c_device_id exc3000_id[] = {
429 	{ "exc3000", EETI_EXC3000 },
430 	{ "exc80h60", EETI_EXC80H60 },
431 	{ "exc80h84", EETI_EXC80H84 },
432 	{ }
433 };
434 MODULE_DEVICE_TABLE(i2c, exc3000_id);
435 
436 #ifdef CONFIG_OF
437 static 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 };
443 MODULE_DEVICE_TABLE(of, exc3000_of_match);
444 #endif
445 
446 static 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 
455 module_i2c_driver(exc3000_driver);
456 
457 MODULE_AUTHOR("Ahmet Inan <inan@distec.de>");
458 MODULE_DESCRIPTION("I2C connected EETI EXC3000 multiple touch controller driver");
459 MODULE_LICENSE("GPL v2");
460