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
 43static const struct i2c_device_id exc3000_id[];
 44
 45struct eeti_dev_info {
 46	const char *name;
 47	int max_xy;
 48};
 49
 50enum eeti_dev_id {
 51	EETI_EXC3000,
 52	EETI_EXC80H60,
 53	EETI_EXC80H84,
 54};
 55
 56static 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
 71struct 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
 83static 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
 99static 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
107static inline void exc3000_schedule_timer(struct exc3000_data *data)
108{
109	mod_timer(&data->timer, jiffies + msecs_to_jiffies(EXC3000_TIMEOUT_MS));
110}
111
112static 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
137static 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
180out_fail:
181	/* Schedule a timer to release "stuck" contacts */
182	exc3000_schedule_timer(data);
183
184	return ret;
185}
186
187static 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
214out:
215	return IRQ_HANDLED;
216}
217
218static 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	unsigned long time_left;
224
225	mutex_lock(&data->query_lock);
226
227	reinit_completion(&data->wait_event);
228
229	buf[5] = request_len;
230	memcpy(&buf[6], request, request_len);
231
232	ret = i2c_master_send(data->client, buf, EXC3000_LEN_VENDOR_REQUEST);
233	if (ret < 0)
234		goto out_unlock;
235
236	if (response) {
237		time_left = wait_for_completion_timeout(&data->wait_event,
238							timeout * HZ);
239		if (time_left == 0) {
240			ret = -ETIMEDOUT;
241			goto out_unlock;
242		}
243
244		if (data->buf[3] >= EXC3000_LEN_FRAME) {
245			ret = -ENOSPC;
246			goto out_unlock;
247		}
248
249		memcpy(response, &data->buf[4], data->buf[3]);
250		ret = data->buf[3];
251	}
252
253out_unlock:
254	mutex_unlock(&data->query_lock);
255
256	return ret;
257}
258
259static ssize_t fw_version_show(struct device *dev,
260			       struct device_attribute *attr, char *buf)
261{
262	struct i2c_client *client = to_i2c_client(dev);
263	struct exc3000_data *data = i2c_get_clientdata(client);
264	u8 response[EXC3000_LEN_FRAME];
265	int ret;
266
267	/* query bootloader info */
268	ret = exc3000_vendor_data_request(data,
269					  (u8[]){0x39, 0x02}, 2, response, 1);
270	if (ret < 0)
271		return ret;
272
273	/*
274	 * If the bootloader version is non-zero then the device is in
275	 * bootloader mode and won't answer a query for the application FW
276	 * version, so we just use the bootloader version info.
277	 */
278	if (response[2] || response[3])
279		return sprintf(buf, "%d.%d\n", response[2], response[3]);
280
281	ret = exc3000_vendor_data_request(data, (u8[]){'D'}, 1, response, 1);
282	if (ret < 0)
283		return ret;
284
285	return sprintf(buf, "%s\n", &response[1]);
286}
287static DEVICE_ATTR_RO(fw_version);
288
289static ssize_t model_show(struct device *dev,
290			  struct device_attribute *attr, char *buf)
291{
292	struct i2c_client *client = to_i2c_client(dev);
293	struct exc3000_data *data = i2c_get_clientdata(client);
294	u8 response[EXC3000_LEN_FRAME];
295	int ret;
296
297	ret = exc3000_vendor_data_request(data, (u8[]){'E'}, 1, response, 1);
298	if (ret < 0)
299		return ret;
300
301	return sprintf(buf, "%s\n", &response[1]);
302}
303static DEVICE_ATTR_RO(model);
304
305static ssize_t type_show(struct device *dev,
306			  struct device_attribute *attr, char *buf)
307{
308	struct i2c_client *client = to_i2c_client(dev);
309	struct exc3000_data *data = i2c_get_clientdata(client);
310	u8 response[EXC3000_LEN_FRAME];
311	int ret;
312
313	ret = exc3000_vendor_data_request(data, (u8[]){'F'}, 1, response, 1);
314	if (ret < 0)
315		return ret;
316
317	return sprintf(buf, "%s\n", &response[1]);
318}
319static DEVICE_ATTR_RO(type);
320
321static struct attribute *sysfs_attrs[] = {
322	&dev_attr_fw_version.attr,
323	&dev_attr_model.attr,
324	&dev_attr_type.attr,
325	NULL
326};
327
328static struct attribute_group exc3000_attribute_group = {
329	.attrs = sysfs_attrs
330};
331
332static int exc3000_probe(struct i2c_client *client)
333{
334	struct exc3000_data *data;
335	struct input_dev *input;
336	int error, max_xy, retry;
337
338	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
339	if (!data)
340		return -ENOMEM;
341
342	data->client = client;
343	data->info = device_get_match_data(&client->dev);
344	if (!data->info) {
345		enum eeti_dev_id eeti_dev_id =
346			i2c_match_id(exc3000_id, client)->driver_data;
347		data->info = &exc3000_info[eeti_dev_id];
348	}
349	timer_setup(&data->timer, exc3000_timer, 0);
350	init_completion(&data->wait_event);
351	mutex_init(&data->query_lock);
352
353	data->reset = devm_gpiod_get_optional(&client->dev, "reset",
354					      GPIOD_OUT_HIGH);
355	if (IS_ERR(data->reset))
356		return PTR_ERR(data->reset);
357
358	if (data->reset) {
359		msleep(EXC3000_RESET_MS);
360		gpiod_set_value_cansleep(data->reset, 0);
361		msleep(EXC3000_READY_MS);
362	}
363
364	input = devm_input_allocate_device(&client->dev);
365	if (!input)
366		return -ENOMEM;
367
368	data->input = input;
369	input_set_drvdata(input, data);
370
371	input->name = data->info->name;
372	input->id.bustype = BUS_I2C;
373
374	max_xy = data->info->max_xy;
375	input_set_abs_params(input, ABS_MT_POSITION_X, 0, max_xy, 0, 0);
376	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, max_xy, 0, 0);
377
378	touchscreen_parse_properties(input, true, &data->prop);
379
380	error = input_mt_init_slots(input, EXC3000_NUM_SLOTS,
381				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
382	if (error)
383		return error;
384
385	error = input_register_device(input);
386	if (error)
387		return error;
388
389	error = devm_request_threaded_irq(&client->dev, client->irq,
390					  NULL, exc3000_interrupt, IRQF_ONESHOT,
391					  client->name, data);
392	if (error)
393		return error;
394
395	/*
396	 * I²C does not have built-in recovery, so retry on failure. This
397	 * ensures, that the device probe will not fail for temporary issues
398	 * on the bus.  This is not needed for the sysfs calls (userspace
399	 * will receive the error code and can start another query) and
400	 * cannot be done for touch events (but that only means loosing one
401	 * or two touch events anyways).
402	 */
403	for (retry = 0; retry < 3; retry++) {
404		u8 response[EXC3000_LEN_FRAME];
405
406		error = exc3000_vendor_data_request(data, (u8[]){'E'}, 1,
407						    response, 1);
408		if (error > 0) {
409			dev_dbg(&client->dev, "TS Model: %s", &response[1]);
410			error = 0;
411			break;
412		}
413		dev_warn(&client->dev, "Retry %d get EETI EXC3000 model: %d\n",
414			 retry + 1, error);
415	}
416
417	if (error)
418		return error;
419
420	i2c_set_clientdata(client, data);
421
422	error = devm_device_add_group(&client->dev, &exc3000_attribute_group);
423	if (error)
424		return error;
425
426	return 0;
427}
428
429static const struct i2c_device_id exc3000_id[] = {
430	{ "exc3000", EETI_EXC3000 },
431	{ "exc80h60", EETI_EXC80H60 },
432	{ "exc80h84", EETI_EXC80H84 },
433	{ }
434};
435MODULE_DEVICE_TABLE(i2c, exc3000_id);
436
437#ifdef CONFIG_OF
438static const struct of_device_id exc3000_of_match[] = {
439	{ .compatible = "eeti,exc3000", .data = &exc3000_info[EETI_EXC3000] },
440	{ .compatible = "eeti,exc80h60", .data = &exc3000_info[EETI_EXC80H60] },
441	{ .compatible = "eeti,exc80h84", .data = &exc3000_info[EETI_EXC80H84] },
442	{ }
443};
444MODULE_DEVICE_TABLE(of, exc3000_of_match);
445#endif
446
447static struct i2c_driver exc3000_driver = {
448	.driver = {
449		.name	= "exc3000",
450		.of_match_table = of_match_ptr(exc3000_of_match),
451	},
452	.id_table	= exc3000_id,
453	.probe_new	= exc3000_probe,
454};
455
456module_i2c_driver(exc3000_driver);
457
458MODULE_AUTHOR("Ahmet Inan <inan@distec.de>");
459MODULE_DESCRIPTION("I2C connected EETI EXC3000 multiple touch controller driver");
460MODULE_LICENSE("GPL v2");