xref: /linux/drivers/input/touchscreen/exc3000.c (revision ffd01c3bcc1af4d8c3e7949152af0d9fe3d1fda5) 
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 <linux/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 	EETI_EXC81W32,
57 };
58 
59 static struct eeti_dev_info exc3000_info[] = {
60 	[EETI_EXC3000] = {
61 		.name = "EETI EXC3000 Touch Screen",
62 		.max_xy = SZ_4K - 1,
63 	},
64 	[EETI_EXC80H60] = {
65 		.name = "EETI EXC80H60 Touch Screen",
66 		.max_xy = SZ_16K - 1,
67 	},
68 	[EETI_EXC80H84] = {
69 		.name = "EETI EXC80H84 Touch Screen",
70 		.max_xy = SZ_16K - 1,
71 	},
72 	[EETI_EXC81W32] = {
73 		.name = "EETI EXC81W32 Touch Screen",
74 		.max_xy = SZ_16K - 1,
75 	},
76 };
77 
78 struct exc3000_data {
79 	struct i2c_client *client;
80 	const struct eeti_dev_info *info;
81 	struct input_dev *input;
82 	struct touchscreen_properties prop;
83 	struct gpio_desc *reset;
84 	struct timer_list timer;
85 	u8 buf[2 * EXC3000_LEN_FRAME];
86 	struct completion wait_event;
87 	struct mutex query_lock;
88 };
89 
90 static void exc3000_report_slots(struct input_dev *input,
91 				 struct touchscreen_properties *prop,
92 				 const u8 *buf, int num)
93 {
94 	for (; num--; buf += EXC3000_LEN_POINT) {
95 		if (buf[0] & BIT(0)) {
96 			input_mt_slot(input, buf[1]);
97 			input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
98 			touchscreen_report_pos(input, prop,
99 					       get_unaligned_le16(buf + 2),
100 					       get_unaligned_le16(buf + 4),
101 					       true);
102 		}
103 	}
104 }
105 
106 static void exc3000_timer(struct timer_list *t)
107 {
108 	struct exc3000_data *data = timer_container_of(data, t, timer);
109 
110 	input_mt_sync_frame(data->input);
111 	input_sync(data->input);
112 }
113 
114 static inline void exc3000_schedule_timer(struct exc3000_data *data)
115 {
116 	mod_timer(&data->timer, jiffies + msecs_to_jiffies(EXC3000_TIMEOUT_MS));
117 }
118 
119 static void exc3000_shutdown_timer(void *timer)
120 {
121 	timer_shutdown_sync(timer);
122 }
123 
124 static int exc3000_read_frame(struct exc3000_data *data, u8 *buf)
125 {
126 	struct i2c_client *client = data->client;
127 	int ret;
128 
129 	ret = i2c_master_send(client, "'", 2);
130 	if (ret < 0)
131 		return ret;
132 
133 	if (ret != 2)
134 		return -EIO;
135 
136 	ret = i2c_master_recv(client, buf, EXC3000_LEN_FRAME);
137 	if (ret < 0)
138 		return ret;
139 
140 	if (ret != EXC3000_LEN_FRAME)
141 		return -EIO;
142 
143 	if (get_unaligned_le16(buf) != EXC3000_LEN_FRAME)
144 		return -EINVAL;
145 
146 	return 0;
147 }
148 
149 static int exc3000_handle_mt_event(struct exc3000_data *data)
150 {
151 	struct input_dev *input = data->input;
152 	int ret, total_slots;
153 	u8 *buf = data->buf;
154 
155 	total_slots = buf[3];
156 	if (!total_slots || total_slots > EXC3000_NUM_SLOTS) {
157 		ret = -EINVAL;
158 		goto out_fail;
159 	}
160 
161 	if (total_slots > EXC3000_SLOTS_PER_FRAME) {
162 		/* Read 2nd frame to get the rest of the contacts. */
163 		ret = exc3000_read_frame(data, buf + EXC3000_LEN_FRAME);
164 		if (ret)
165 			goto out_fail;
166 
167 		/* 2nd chunk must have number of contacts set to 0. */
168 		if (buf[EXC3000_LEN_FRAME + 3] != 0) {
169 			ret = -EINVAL;
170 			goto out_fail;
171 		}
172 	}
173 
174 	/*
175 	 * We read full state successfully, no contacts will be "stuck".
176 	 */
177 	timer_delete_sync(&data->timer);
178 
179 	while (total_slots > 0) {
180 		int slots = min(total_slots, EXC3000_SLOTS_PER_FRAME);
181 
182 		exc3000_report_slots(input, &data->prop, buf + 4, slots);
183 		total_slots -= slots;
184 		buf += EXC3000_LEN_FRAME;
185 	}
186 
187 	input_mt_sync_frame(input);
188 	input_sync(input);
189 
190 	return 0;
191 
192 out_fail:
193 	/* Schedule a timer to release "stuck" contacts */
194 	exc3000_schedule_timer(data);
195 
196 	return ret;
197 }
198 
199 static irqreturn_t exc3000_interrupt(int irq, void *dev_id)
200 {
201 	struct exc3000_data *data = dev_id;
202 	u8 *buf = data->buf;
203 	int ret;
204 
205 	ret = exc3000_read_frame(data, buf);
206 	if (ret) {
207 		/* Schedule a timer to release "stuck" contacts */
208 		exc3000_schedule_timer(data);
209 		goto out;
210 	}
211 
212 	switch (buf[2]) {
213 	case EXC3000_VENDOR_EVENT:
214 		complete(&data->wait_event);
215 		break;
216 
217 	case EXC3000_MT1_EVENT:
218 	case EXC3000_MT2_EVENT:
219 		exc3000_handle_mt_event(data);
220 		break;
221 
222 	default:
223 		break;
224 	}
225 
226 out:
227 	return IRQ_HANDLED;
228 }
229 
230 static int exc3000_vendor_data_request(struct exc3000_data *data, u8 *request,
231 				       u8 request_len, u8 *response, int timeout)
232 {
233 	u8 buf[EXC3000_LEN_VENDOR_REQUEST] = { 0x67, 0x00, 0x42, 0x00, 0x03 };
234 	int ret;
235 	unsigned long time_left;
236 
237 	guard(mutex)(&data->query_lock);
238 
239 	reinit_completion(&data->wait_event);
240 
241 	buf[5] = request_len;
242 	memcpy(&buf[6], request, request_len);
243 
244 	ret = i2c_master_send(data->client, buf, EXC3000_LEN_VENDOR_REQUEST);
245 	if (ret < 0)
246 		return ret;
247 
248 	time_left = wait_for_completion_timeout(&data->wait_event,
249 						timeout * HZ);
250 	if (time_left == 0)
251 		return -ETIMEDOUT;
252 
253 	if (data->buf[3] >= EXC3000_LEN_FRAME)
254 		return -ENOSPC;
255 
256 	memcpy(response, &data->buf[4], data->buf[3]);
257 	return data->buf[3];
258 }
259 
260 static ssize_t fw_version_show(struct device *dev,
261 			       struct device_attribute *attr, char *buf)
262 {
263 	struct i2c_client *client = to_i2c_client(dev);
264 	struct exc3000_data *data = i2c_get_clientdata(client);
265 	u8 response[EXC3000_LEN_FRAME];
266 	int ret;
267 
268 	/* query bootloader info */
269 	ret = exc3000_vendor_data_request(data,
270 					  (u8[]){0x39, 0x02}, 2, response, 1);
271 	if (ret < 0)
272 		return ret;
273 
274 	/*
275 	 * If the bootloader version is non-zero then the device is in
276 	 * bootloader mode and won't answer a query for the application FW
277 	 * version, so we just use the bootloader version info.
278 	 */
279 	if (response[2] || response[3])
280 		return sprintf(buf, "%d.%d\n", response[2], response[3]);
281 
282 	ret = exc3000_vendor_data_request(data, (u8[]){'D'}, 1, response, 1);
283 	if (ret < 0)
284 		return ret;
285 
286 	return sprintf(buf, "%s\n", &response[1]);
287 }
288 static DEVICE_ATTR_RO(fw_version);
289 
290 static ssize_t model_show(struct device *dev,
291 			  struct device_attribute *attr, char *buf)
292 {
293 	struct i2c_client *client = to_i2c_client(dev);
294 	struct exc3000_data *data = i2c_get_clientdata(client);
295 	u8 response[EXC3000_LEN_FRAME];
296 	int ret;
297 
298 	ret = exc3000_vendor_data_request(data, (u8[]){'E'}, 1, response, 1);
299 	if (ret < 0)
300 		return ret;
301 
302 	return sprintf(buf, "%s\n", &response[1]);
303 }
304 static DEVICE_ATTR_RO(model);
305 
306 static ssize_t type_show(struct device *dev,
307 			  struct device_attribute *attr, char *buf)
308 {
309 	struct i2c_client *client = to_i2c_client(dev);
310 	struct exc3000_data *data = i2c_get_clientdata(client);
311 	u8 response[EXC3000_LEN_FRAME];
312 	int ret;
313 
314 	ret = exc3000_vendor_data_request(data, (u8[]){'F'}, 1, response, 1);
315 	if (ret < 0)
316 		return ret;
317 
318 	return sprintf(buf, "%s\n", &response[1]);
319 }
320 static DEVICE_ATTR_RO(type);
321 
322 static struct attribute *exc3000_attrs[] = {
323 	&dev_attr_fw_version.attr,
324 	&dev_attr_model.attr,
325 	&dev_attr_type.attr,
326 	NULL
327 };
328 ATTRIBUTE_GROUPS(exc3000);
329 
330 static int exc3000_probe(struct i2c_client *client)
331 {
332 	struct exc3000_data *data;
333 	struct input_dev *input;
334 	int error, max_xy, retry;
335 
336 	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
337 	if (!data)
338 		return -ENOMEM;
339 
340 	data->client = client;
341 	data->info = device_get_match_data(&client->dev);
342 	if (!data->info) {
343 		enum eeti_dev_id eeti_dev_id =
344 			i2c_match_id(exc3000_id, client)->driver_data;
345 		data->info = &exc3000_info[eeti_dev_id];
346 	}
347 	timer_setup(&data->timer, exc3000_timer, 0);
348 	init_completion(&data->wait_event);
349 	mutex_init(&data->query_lock);
350 
351 	data->reset = devm_gpiod_get_optional(&client->dev, "reset",
352 					      GPIOD_OUT_HIGH);
353 	if (IS_ERR(data->reset))
354 		return PTR_ERR(data->reset);
355 
356 	/* For proper reset sequence, enable power while reset asserted */
357 	error = devm_regulator_get_enable(&client->dev, "vdd");
358 	if (error && error != -ENODEV)
359 		return dev_err_probe(&client->dev, error,
360 				     "failed to request vdd regulator\n");
361 
362 	if (data->reset) {
363 		msleep(EXC3000_RESET_MS);
364 		gpiod_set_value_cansleep(data->reset, 0);
365 		msleep(EXC3000_READY_MS);
366 	}
367 
368 	input = devm_input_allocate_device(&client->dev);
369 	if (!input)
370 		return -ENOMEM;
371 
372 	data->input = input;
373 	input_set_drvdata(input, data);
374 
375 	input->name = data->info->name;
376 	input->id.bustype = BUS_I2C;
377 
378 	max_xy = data->info->max_xy;
379 	input_set_abs_params(input, ABS_MT_POSITION_X, 0, max_xy, 0, 0);
380 	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, max_xy, 0, 0);
381 
382 	touchscreen_parse_properties(input, true, &data->prop);
383 
384 	error = input_mt_init_slots(input, EXC3000_NUM_SLOTS,
385 				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
386 	if (error)
387 		return error;
388 
389 	error = input_register_device(input);
390 	if (error)
391 		return error;
392 
393 	error = devm_add_action_or_reset(&client->dev, exc3000_shutdown_timer,
394 					 &data->timer);
395 	if (error)
396 		return error;
397 
398 	error = devm_request_threaded_irq(&client->dev, client->irq,
399 					  NULL, exc3000_interrupt, IRQF_ONESHOT,
400 					  client->name, data);
401 	if (error)
402 		return error;
403 
404 	/*
405 	 * I²C does not have built-in recovery, so retry on failure. This
406 	 * ensures, that the device probe will not fail for temporary issues
407 	 * on the bus.  This is not needed for the sysfs calls (userspace
408 	 * will receive the error code and can start another query) and
409 	 * cannot be done for touch events (but that only means loosing one
410 	 * or two touch events anyways).
411 	 */
412 	for (retry = 0; retry < 3; retry++) {
413 		u8 response[EXC3000_LEN_FRAME];
414 
415 		error = exc3000_vendor_data_request(data, (u8[]){'E'}, 1,
416 						    response, 1);
417 		if (error > 0) {
418 			dev_dbg(&client->dev, "TS Model: %s", &response[1]);
419 			error = 0;
420 			break;
421 		}
422 		dev_warn(&client->dev, "Retry %d get EETI EXC3000 model: %d\n",
423 			 retry + 1, error);
424 	}
425 
426 	if (error)
427 		return error;
428 
429 	i2c_set_clientdata(client, data);
430 
431 	return 0;
432 }
433 
434 static const struct i2c_device_id exc3000_id[] = {
435 	{ "exc3000", EETI_EXC3000 },
436 	{ "exc80h60", EETI_EXC80H60 },
437 	{ "exc80h84", EETI_EXC80H84 },
438 	{ "exc81w32", EETI_EXC81W32 },
439 	{ }
440 };
441 MODULE_DEVICE_TABLE(i2c, exc3000_id);
442 
443 #ifdef CONFIG_OF
444 static const struct of_device_id exc3000_of_match[] = {
445 	{ .compatible = "eeti,exc3000", .data = &exc3000_info[EETI_EXC3000] },
446 	{ .compatible = "eeti,exc80h60", .data = &exc3000_info[EETI_EXC80H60] },
447 	{ .compatible = "eeti,exc80h84", .data = &exc3000_info[EETI_EXC80H84] },
448 	{ .compatible = "eeti,exc81w32", .data = &exc3000_info[EETI_EXC81W32] },
449 	{ }
450 };
451 MODULE_DEVICE_TABLE(of, exc3000_of_match);
452 #endif
453 
454 #ifdef CONFIG_ACPI
455 static const struct acpi_device_id exc3000_acpi_match[] = {
456 	{ "EGA00001", .driver_data = (kernel_ulong_t)&exc3000_info[EETI_EXC80H60] },
457 	{ }
458 };
459 MODULE_DEVICE_TABLE(acpi, exc3000_acpi_match);
460 #endif
461 
462 static struct i2c_driver exc3000_driver = {
463 	.driver = {
464 		.name	= "exc3000",
465 		.dev_groups = exc3000_groups,
466 		.of_match_table = of_match_ptr(exc3000_of_match),
467 		.acpi_match_table = ACPI_PTR(exc3000_acpi_match),
468 	},
469 	.id_table	= exc3000_id,
470 	.probe		= exc3000_probe,
471 };
472 
473 module_i2c_driver(exc3000_driver);
474 
475 MODULE_AUTHOR("Ahmet Inan <inan@distec.de>");
476 MODULE_DESCRIPTION("I2C connected EETI EXC3000 multiple touch controller driver");
477 MODULE_LICENSE("GPL v2");
478