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
45static const struct i2c_device_id exc3000_id[];
46
47struct eeti_dev_info {
48	const char *name;
49	int max_xy;
50};
51
52enum eeti_dev_id {
53	EETI_EXC3000,
54	EETI_EXC80H60,
55	EETI_EXC80H84,
56};
57
58static 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
73struct 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
85static 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
101static 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
109static inline void exc3000_schedule_timer(struct exc3000_data *data)
110{
111	mod_timer(&data->timer, jiffies + msecs_to_jiffies(EXC3000_TIMEOUT_MS));
112}
113
114static void exc3000_shutdown_timer(void *timer)
115{
116	timer_shutdown_sync(timer);
117}
118
119static 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
144static 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
187out_fail:
188	/* Schedule a timer to release "stuck" contacts */
189	exc3000_schedule_timer(data);
190
191	return ret;
192}
193
194static 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
221out:
222	return IRQ_HANDLED;
223}
224
225static 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
260out_unlock:
261	mutex_unlock(&data->query_lock);
262
263	return ret;
264}
265
266static 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}
294static DEVICE_ATTR_RO(fw_version);
295
296static 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}
310static DEVICE_ATTR_RO(model);
311
312static 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}
326static DEVICE_ATTR_RO(type);
327
328static struct attribute *sysfs_attrs[] = {
329	&dev_attr_fw_version.attr,
330	&dev_attr_model.attr,
331	&dev_attr_type.attr,
332	NULL
333};
334
335static struct attribute_group exc3000_attribute_group = {
336	.attrs = sysfs_attrs
337};
338
339static int exc3000_probe(struct i2c_client *client)
340{
341	struct exc3000_data *data;
342	struct input_dev *input;
343	int error, max_xy, retry;
344
345	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
346	if (!data)
347		return -ENOMEM;
348
349	data->client = client;
350	data->info = device_get_match_data(&client->dev);
351	if (!data->info) {
352		enum eeti_dev_id eeti_dev_id =
353			i2c_match_id(exc3000_id, client)->driver_data;
354		data->info = &exc3000_info[eeti_dev_id];
355	}
356	timer_setup(&data->timer, exc3000_timer, 0);
357	init_completion(&data->wait_event);
358	mutex_init(&data->query_lock);
359
360	data->reset = devm_gpiod_get_optional(&client->dev, "reset",
361					      GPIOD_OUT_HIGH);
362	if (IS_ERR(data->reset))
363		return PTR_ERR(data->reset);
364
365	/* For proper reset sequence, enable power while reset asserted */
366	error = devm_regulator_get_enable(&client->dev, "vdd");
367	if (error && error != -ENODEV)
368		return dev_err_probe(&client->dev, error,
369				     "failed to request vdd regulator\n");
370
371	if (data->reset) {
372		msleep(EXC3000_RESET_MS);
373		gpiod_set_value_cansleep(data->reset, 0);
374		msleep(EXC3000_READY_MS);
375	}
376
377	input = devm_input_allocate_device(&client->dev);
378	if (!input)
379		return -ENOMEM;
380
381	data->input = input;
382	input_set_drvdata(input, data);
383
384	input->name = data->info->name;
385	input->id.bustype = BUS_I2C;
386
387	max_xy = data->info->max_xy;
388	input_set_abs_params(input, ABS_MT_POSITION_X, 0, max_xy, 0, 0);
389	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, max_xy, 0, 0);
390
391	touchscreen_parse_properties(input, true, &data->prop);
392
393	error = input_mt_init_slots(input, EXC3000_NUM_SLOTS,
394				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
395	if (error)
396		return error;
397
398	error = input_register_device(input);
399	if (error)
400		return error;
401
402	error = devm_add_action_or_reset(&client->dev, exc3000_shutdown_timer,
403					 &data->timer);
404	if (error)
405		return error;
406
407	error = devm_request_threaded_irq(&client->dev, client->irq,
408					  NULL, exc3000_interrupt, IRQF_ONESHOT,
409					  client->name, data);
410	if (error)
411		return error;
412
413	/*
414	 * I²C does not have built-in recovery, so retry on failure. This
415	 * ensures, that the device probe will not fail for temporary issues
416	 * on the bus.  This is not needed for the sysfs calls (userspace
417	 * will receive the error code and can start another query) and
418	 * cannot be done for touch events (but that only means loosing one
419	 * or two touch events anyways).
420	 */
421	for (retry = 0; retry < 3; retry++) {
422		u8 response[EXC3000_LEN_FRAME];
423
424		error = exc3000_vendor_data_request(data, (u8[]){'E'}, 1,
425						    response, 1);
426		if (error > 0) {
427			dev_dbg(&client->dev, "TS Model: %s", &response[1]);
428			error = 0;
429			break;
430		}
431		dev_warn(&client->dev, "Retry %d get EETI EXC3000 model: %d\n",
432			 retry + 1, error);
433	}
434
435	if (error)
436		return error;
437
438	i2c_set_clientdata(client, data);
439
440	error = devm_device_add_group(&client->dev, &exc3000_attribute_group);
441	if (error)
442		return error;
443
444	return 0;
445}
446
447static const struct i2c_device_id exc3000_id[] = {
448	{ "exc3000", EETI_EXC3000 },
449	{ "exc80h60", EETI_EXC80H60 },
450	{ "exc80h84", EETI_EXC80H84 },
451	{ }
452};
453MODULE_DEVICE_TABLE(i2c, exc3000_id);
454
455#ifdef CONFIG_OF
456static const struct of_device_id exc3000_of_match[] = {
457	{ .compatible = "eeti,exc3000", .data = &exc3000_info[EETI_EXC3000] },
458	{ .compatible = "eeti,exc80h60", .data = &exc3000_info[EETI_EXC80H60] },
459	{ .compatible = "eeti,exc80h84", .data = &exc3000_info[EETI_EXC80H84] },
460	{ }
461};
462MODULE_DEVICE_TABLE(of, exc3000_of_match);
463#endif
464
465#ifdef CONFIG_ACPI
466static const struct acpi_device_id exc3000_acpi_match[] = {
467	{ "EGA00001", .driver_data = (kernel_ulong_t)&exc3000_info[EETI_EXC80H60] },
468	{ }
469};
470MODULE_DEVICE_TABLE(acpi, exc3000_acpi_match);
471#endif
472
473static struct i2c_driver exc3000_driver = {
474	.driver = {
475		.name	= "exc3000",
476		.of_match_table = of_match_ptr(exc3000_of_match),
477		.acpi_match_table = ACPI_PTR(exc3000_acpi_match),
478	},
479	.id_table	= exc3000_id,
480	.probe		= exc3000_probe,
481};
482
483module_i2c_driver(exc3000_driver);
484
485MODULE_AUTHOR("Ahmet Inan <inan@distec.de>");
486MODULE_DESCRIPTION("I2C connected EETI EXC3000 multiple touch controller driver");
487MODULE_LICENSE("GPL v2");
488