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_POINT		10
29 
30 #define EXC3000_LEN_MODEL_NAME		16
31 #define EXC3000_LEN_FW_VERSION		16
32 
33 #define EXC3000_MT1_EVENT		0x06
34 #define EXC3000_MT2_EVENT		0x18
35 
36 #define EXC3000_TIMEOUT_MS		100
37 
38 #define EXC3000_RESET_MS		10
39 #define EXC3000_READY_MS		100
40 
41 static const struct i2c_device_id exc3000_id[];
42 
43 struct eeti_dev_info {
44 	const char *name;
45 	int max_xy;
46 };
47 
48 enum eeti_dev_id {
49 	EETI_EXC3000,
50 	EETI_EXC80H60,
51 	EETI_EXC80H84,
52 };
53 
54 static struct eeti_dev_info exc3000_info[] = {
55 	[EETI_EXC3000] = {
56 		.name = "EETI EXC3000 Touch Screen",
57 		.max_xy = SZ_4K - 1,
58 	},
59 	[EETI_EXC80H60] = {
60 		.name = "EETI EXC80H60 Touch Screen",
61 		.max_xy = SZ_16K - 1,
62 	},
63 	[EETI_EXC80H84] = {
64 		.name = "EETI EXC80H84 Touch Screen",
65 		.max_xy = SZ_16K - 1,
66 	},
67 };
68 
69 struct exc3000_data {
70 	struct i2c_client *client;
71 	const struct eeti_dev_info *info;
72 	struct input_dev *input;
73 	struct touchscreen_properties prop;
74 	struct gpio_desc *reset;
75 	struct timer_list timer;
76 	u8 buf[2 * EXC3000_LEN_FRAME];
77 	struct completion wait_event;
78 	struct mutex query_lock;
79 	int query_result;
80 	char model[EXC3000_LEN_MODEL_NAME];
81 	char fw_version[EXC3000_LEN_FW_VERSION];
82 };
83 
84 static void exc3000_report_slots(struct input_dev *input,
85 				 struct touchscreen_properties *prop,
86 				 const u8 *buf, int num)
87 {
88 	for (; num--; buf += EXC3000_LEN_POINT) {
89 		if (buf[0] & BIT(0)) {
90 			input_mt_slot(input, buf[1]);
91 			input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
92 			touchscreen_report_pos(input, prop,
93 					       get_unaligned_le16(buf + 2),
94 					       get_unaligned_le16(buf + 4),
95 					       true);
96 		}
97 	}
98 }
99 
100 static void exc3000_timer(struct timer_list *t)
101 {
102 	struct exc3000_data *data = from_timer(data, t, timer);
103 
104 	input_mt_sync_frame(data->input);
105 	input_sync(data->input);
106 }
107 
108 static int exc3000_read_frame(struct exc3000_data *data, u8 *buf)
109 {
110 	struct i2c_client *client = data->client;
111 	u8 expected_event = EXC3000_MT1_EVENT;
112 	int ret;
113 
114 	if (data->info->max_xy == SZ_16K - 1)
115 		expected_event = EXC3000_MT2_EVENT;
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 	if (buf[2] != expected_event)
135 		return -EINVAL;
136 
137 	return 0;
138 }
139 
140 static int exc3000_read_data(struct exc3000_data *data,
141 			     u8 *buf, int *n_slots)
142 {
143 	int error;
144 
145 	error = exc3000_read_frame(data, buf);
146 	if (error)
147 		return error;
148 
149 	*n_slots = buf[3];
150 	if (!*n_slots || *n_slots > EXC3000_NUM_SLOTS)
151 		return -EINVAL;
152 
153 	if (*n_slots > EXC3000_SLOTS_PER_FRAME) {
154 		/* Read 2nd frame to get the rest of the contacts. */
155 		error = exc3000_read_frame(data, buf + EXC3000_LEN_FRAME);
156 		if (error)
157 			return error;
158 
159 		/* 2nd chunk must have number of contacts set to 0. */
160 		if (buf[EXC3000_LEN_FRAME + 3] != 0)
161 			return -EINVAL;
162 	}
163 
164 	return 0;
165 }
166 
167 static int exc3000_query_interrupt(struct exc3000_data *data)
168 {
169 	u8 *buf = data->buf;
170 	int error;
171 
172 	error = i2c_master_recv(data->client, buf, EXC3000_LEN_FRAME);
173 	if (error < 0)
174 		return error;
175 
176 	if (buf[0] != 'B')
177 		return -EPROTO;
178 
179 	if (buf[4] == 'E')
180 		strlcpy(data->model, buf + 5, sizeof(data->model));
181 	else if (buf[4] == 'D')
182 		strlcpy(data->fw_version, buf + 5, sizeof(data->fw_version));
183 	else
184 		return -EPROTO;
185 
186 	return 0;
187 }
188 
189 static irqreturn_t exc3000_interrupt(int irq, void *dev_id)
190 {
191 	struct exc3000_data *data = dev_id;
192 	struct input_dev *input = data->input;
193 	u8 *buf = data->buf;
194 	int slots, total_slots;
195 	int error;
196 
197 	if (mutex_is_locked(&data->query_lock)) {
198 		data->query_result = exc3000_query_interrupt(data);
199 		complete(&data->wait_event);
200 		goto out;
201 	}
202 
203 	error = exc3000_read_data(data, buf, &total_slots);
204 	if (error) {
205 		/* Schedule a timer to release "stuck" contacts */
206 		mod_timer(&data->timer,
207 			  jiffies + msecs_to_jiffies(EXC3000_TIMEOUT_MS));
208 		goto out;
209 	}
210 
211 	/*
212 	 * We read full state successfully, no contacts will be "stuck".
213 	 */
214 	del_timer_sync(&data->timer);
215 
216 	while (total_slots > 0) {
217 		slots = min(total_slots, EXC3000_SLOTS_PER_FRAME);
218 		exc3000_report_slots(input, &data->prop, buf + 4, slots);
219 		total_slots -= slots;
220 		buf += EXC3000_LEN_FRAME;
221 	}
222 
223 	input_mt_sync_frame(input);
224 	input_sync(input);
225 
226 out:
227 	return IRQ_HANDLED;
228 }
229 
230 static ssize_t fw_version_show(struct device *dev,
231 			       struct device_attribute *attr, char *buf)
232 {
233 	struct i2c_client *client = to_i2c_client(dev);
234 	struct exc3000_data *data = i2c_get_clientdata(client);
235 	static const u8 request[68] = {
236 		0x67, 0x00, 0x42, 0x00, 0x03, 0x01, 'D', 0x00
237 	};
238 	int error;
239 
240 	mutex_lock(&data->query_lock);
241 
242 	data->query_result = -ETIMEDOUT;
243 	reinit_completion(&data->wait_event);
244 
245 	error = i2c_master_send(client, request, sizeof(request));
246 	if (error < 0) {
247 		mutex_unlock(&data->query_lock);
248 		return error;
249 	}
250 
251 	wait_for_completion_interruptible_timeout(&data->wait_event, 1 * HZ);
252 	mutex_unlock(&data->query_lock);
253 
254 	if (data->query_result < 0)
255 		return data->query_result;
256 
257 	return sprintf(buf, "%s\n", data->fw_version);
258 }
259 static DEVICE_ATTR_RO(fw_version);
260 
261 static ssize_t exc3000_get_model(struct exc3000_data *data)
262 {
263 	static const u8 request[68] = {
264 		0x67, 0x00, 0x42, 0x00, 0x03, 0x01, 'E', 0x00
265 	};
266 	struct i2c_client *client = data->client;
267 	int error;
268 
269 	mutex_lock(&data->query_lock);
270 	data->query_result = -ETIMEDOUT;
271 	reinit_completion(&data->wait_event);
272 
273 	error = i2c_master_send(client, request, sizeof(request));
274 	if (error < 0) {
275 		mutex_unlock(&data->query_lock);
276 		return error;
277 	}
278 
279 	wait_for_completion_interruptible_timeout(&data->wait_event, 1 * HZ);
280 	mutex_unlock(&data->query_lock);
281 
282 	return data->query_result;
283 }
284 
285 static ssize_t model_show(struct device *dev,
286 			  struct device_attribute *attr, char *buf)
287 {
288 	struct i2c_client *client = to_i2c_client(dev);
289 	struct exc3000_data *data = i2c_get_clientdata(client);
290 	int error;
291 
292 	error = exc3000_get_model(data);
293 	if (error < 0)
294 		return error;
295 
296 	return sprintf(buf, "%s\n", data->model);
297 }
298 static DEVICE_ATTR_RO(model);
299 
300 static struct attribute *sysfs_attrs[] = {
301 	&dev_attr_fw_version.attr,
302 	&dev_attr_model.attr,
303 	NULL
304 };
305 
306 static struct attribute_group exc3000_attribute_group = {
307 	.attrs = sysfs_attrs
308 };
309 
310 static int exc3000_probe(struct i2c_client *client)
311 {
312 	struct exc3000_data *data;
313 	struct input_dev *input;
314 	int error, max_xy, retry;
315 
316 	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
317 	if (!data)
318 		return -ENOMEM;
319 
320 	data->client = client;
321 	data->info = device_get_match_data(&client->dev);
322 	if (!data->info) {
323 		enum eeti_dev_id eeti_dev_id =
324 			i2c_match_id(exc3000_id, client)->driver_data;
325 		data->info = &exc3000_info[eeti_dev_id];
326 	}
327 	timer_setup(&data->timer, exc3000_timer, 0);
328 	init_completion(&data->wait_event);
329 	mutex_init(&data->query_lock);
330 
331 	data->reset = devm_gpiod_get_optional(&client->dev, "reset",
332 					      GPIOD_OUT_HIGH);
333 	if (IS_ERR(data->reset))
334 		return PTR_ERR(data->reset);
335 
336 	if (data->reset) {
337 		msleep(EXC3000_RESET_MS);
338 		gpiod_set_value_cansleep(data->reset, 0);
339 		msleep(EXC3000_READY_MS);
340 	}
341 
342 	input = devm_input_allocate_device(&client->dev);
343 	if (!input)
344 		return -ENOMEM;
345 
346 	data->input = input;
347 	input_set_drvdata(input, data);
348 
349 	input->name = data->info->name;
350 	input->id.bustype = BUS_I2C;
351 
352 	max_xy = data->info->max_xy;
353 	input_set_abs_params(input, ABS_MT_POSITION_X, 0, max_xy, 0, 0);
354 	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, max_xy, 0, 0);
355 
356 	touchscreen_parse_properties(input, true, &data->prop);
357 
358 	error = input_mt_init_slots(input, EXC3000_NUM_SLOTS,
359 				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
360 	if (error)
361 		return error;
362 
363 	error = input_register_device(input);
364 	if (error)
365 		return error;
366 
367 	error = devm_request_threaded_irq(&client->dev, client->irq,
368 					  NULL, exc3000_interrupt, IRQF_ONESHOT,
369 					  client->name, data);
370 	if (error)
371 		return error;
372 
373 	/*
374 	 * I²C does not have built-in recovery, so retry on failure. This
375 	 * ensures, that the device probe will not fail for temporary issues
376 	 * on the bus.  This is not needed for the sysfs calls (userspace
377 	 * will receive the error code and can start another query) and
378 	 * cannot be done for touch events (but that only means loosing one
379 	 * or two touch events anyways).
380 	 */
381 	for (retry = 0; retry < 3; retry++) {
382 		error = exc3000_get_model(data);
383 		if (!error)
384 			break;
385 		dev_warn(&client->dev, "Retry %d get EETI EXC3000 model: %d\n",
386 			 retry + 1, error);
387 	}
388 
389 	if (error)
390 		return error;
391 
392 	dev_dbg(&client->dev, "TS Model: %s", data->model);
393 
394 	i2c_set_clientdata(client, data);
395 
396 	error = devm_device_add_group(&client->dev, &exc3000_attribute_group);
397 	if (error)
398 		return error;
399 
400 	return 0;
401 }
402 
403 static const struct i2c_device_id exc3000_id[] = {
404 	{ "exc3000", EETI_EXC3000 },
405 	{ "exc80h60", EETI_EXC80H60 },
406 	{ "exc80h84", EETI_EXC80H84 },
407 	{ }
408 };
409 MODULE_DEVICE_TABLE(i2c, exc3000_id);
410 
411 #ifdef CONFIG_OF
412 static const struct of_device_id exc3000_of_match[] = {
413 	{ .compatible = "eeti,exc3000", .data = &exc3000_info[EETI_EXC3000] },
414 	{ .compatible = "eeti,exc80h60", .data = &exc3000_info[EETI_EXC80H60] },
415 	{ .compatible = "eeti,exc80h84", .data = &exc3000_info[EETI_EXC80H84] },
416 	{ }
417 };
418 MODULE_DEVICE_TABLE(of, exc3000_of_match);
419 #endif
420 
421 static struct i2c_driver exc3000_driver = {
422 	.driver = {
423 		.name	= "exc3000",
424 		.of_match_table = of_match_ptr(exc3000_of_match),
425 	},
426 	.id_table	= exc3000_id,
427 	.probe_new	= exc3000_probe,
428 };
429 
430 module_i2c_driver(exc3000_driver);
431 
432 MODULE_AUTHOR("Ahmet Inan <inan@distec.de>");
433 MODULE_DESCRIPTION("I2C connected EETI EXC3000 multiple touch controller driver");
434 MODULE_LICENSE("GPL v2");
435