xref: /linux/drivers/input/touchscreen/exc3000.c (revision d0fde6aae2bacdc024fff43461ba0f325375fa97) 
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 
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 
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 
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 
114 static void exc3000_shutdown_timer(void *timer)
115 {
116 	timer_shutdown_sync(timer);
117 }
118 
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 
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 
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 
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 
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 
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 
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 *exc3000_attrs[] = {
329 	&dev_attr_fw_version.attr,
330 	&dev_attr_model.attr,
331 	&dev_attr_type.attr,
332 	NULL
333 };
334 ATTRIBUTE_GROUPS(exc3000);
335 
336 static int exc3000_probe(struct i2c_client *client)
337 {
338 	struct exc3000_data *data;
339 	struct input_dev *input;
340 	int error, max_xy, retry;
341 
342 	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
343 	if (!data)
344 		return -ENOMEM;
345 
346 	data->client = client;
347 	data->info = device_get_match_data(&client->dev);
348 	if (!data->info) {
349 		enum eeti_dev_id eeti_dev_id =
350 			i2c_match_id(exc3000_id, client)->driver_data;
351 		data->info = &exc3000_info[eeti_dev_id];
352 	}
353 	timer_setup(&data->timer, exc3000_timer, 0);
354 	init_completion(&data->wait_event);
355 	mutex_init(&data->query_lock);
356 
357 	data->reset = devm_gpiod_get_optional(&client->dev, "reset",
358 					      GPIOD_OUT_HIGH);
359 	if (IS_ERR(data->reset))
360 		return PTR_ERR(data->reset);
361 
362 	/* For proper reset sequence, enable power while reset asserted */
363 	error = devm_regulator_get_enable(&client->dev, "vdd");
364 	if (error && error != -ENODEV)
365 		return dev_err_probe(&client->dev, error,
366 				     "failed to request vdd regulator\n");
367 
368 	if (data->reset) {
369 		msleep(EXC3000_RESET_MS);
370 		gpiod_set_value_cansleep(data->reset, 0);
371 		msleep(EXC3000_READY_MS);
372 	}
373 
374 	input = devm_input_allocate_device(&client->dev);
375 	if (!input)
376 		return -ENOMEM;
377 
378 	data->input = input;
379 	input_set_drvdata(input, data);
380 
381 	input->name = data->info->name;
382 	input->id.bustype = BUS_I2C;
383 
384 	max_xy = data->info->max_xy;
385 	input_set_abs_params(input, ABS_MT_POSITION_X, 0, max_xy, 0, 0);
386 	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, max_xy, 0, 0);
387 
388 	touchscreen_parse_properties(input, true, &data->prop);
389 
390 	error = input_mt_init_slots(input, EXC3000_NUM_SLOTS,
391 				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
392 	if (error)
393 		return error;
394 
395 	error = input_register_device(input);
396 	if (error)
397 		return error;
398 
399 	error = devm_add_action_or_reset(&client->dev, exc3000_shutdown_timer,
400 					 &data->timer);
401 	if (error)
402 		return error;
403 
404 	error = devm_request_threaded_irq(&client->dev, client->irq,
405 					  NULL, exc3000_interrupt, IRQF_ONESHOT,
406 					  client->name, data);
407 	if (error)
408 		return error;
409 
410 	/*
411 	 * I²C does not have built-in recovery, so retry on failure. This
412 	 * ensures, that the device probe will not fail for temporary issues
413 	 * on the bus.  This is not needed for the sysfs calls (userspace
414 	 * will receive the error code and can start another query) and
415 	 * cannot be done for touch events (but that only means loosing one
416 	 * or two touch events anyways).
417 	 */
418 	for (retry = 0; retry < 3; retry++) {
419 		u8 response[EXC3000_LEN_FRAME];
420 
421 		error = exc3000_vendor_data_request(data, (u8[]){'E'}, 1,
422 						    response, 1);
423 		if (error > 0) {
424 			dev_dbg(&client->dev, "TS Model: %s", &response[1]);
425 			error = 0;
426 			break;
427 		}
428 		dev_warn(&client->dev, "Retry %d get EETI EXC3000 model: %d\n",
429 			 retry + 1, error);
430 	}
431 
432 	if (error)
433 		return error;
434 
435 	i2c_set_clientdata(client, data);
436 
437 	return 0;
438 }
439 
440 static const struct i2c_device_id exc3000_id[] = {
441 	{ "exc3000", EETI_EXC3000 },
442 	{ "exc80h60", EETI_EXC80H60 },
443 	{ "exc80h84", EETI_EXC80H84 },
444 	{ }
445 };
446 MODULE_DEVICE_TABLE(i2c, exc3000_id);
447 
448 #ifdef CONFIG_OF
449 static const struct of_device_id exc3000_of_match[] = {
450 	{ .compatible = "eeti,exc3000", .data = &exc3000_info[EETI_EXC3000] },
451 	{ .compatible = "eeti,exc80h60", .data = &exc3000_info[EETI_EXC80H60] },
452 	{ .compatible = "eeti,exc80h84", .data = &exc3000_info[EETI_EXC80H84] },
453 	{ }
454 };
455 MODULE_DEVICE_TABLE(of, exc3000_of_match);
456 #endif
457 
458 #ifdef CONFIG_ACPI
459 static const struct acpi_device_id exc3000_acpi_match[] = {
460 	{ "EGA00001", .driver_data = (kernel_ulong_t)&exc3000_info[EETI_EXC80H60] },
461 	{ }
462 };
463 MODULE_DEVICE_TABLE(acpi, exc3000_acpi_match);
464 #endif
465 
466 static struct i2c_driver exc3000_driver = {
467 	.driver = {
468 		.name	= "exc3000",
469 		.dev_groups = exc3000_groups,
470 		.of_match_table = of_match_ptr(exc3000_of_match),
471 		.acpi_match_table = ACPI_PTR(exc3000_acpi_match),
472 	},
473 	.id_table	= exc3000_id,
474 	.probe		= exc3000_probe,
475 };
476 
477 module_i2c_driver(exc3000_driver);
478 
479 MODULE_AUTHOR("Ahmet Inan <inan@distec.de>");
480 MODULE_DESCRIPTION("I2C connected EETI EXC3000 multiple touch controller driver");
481 MODULE_LICENSE("GPL v2");
482