1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2012-2013 MundoReader S.L.
4  * Author: Heiko Stuebner <heiko@sntech.de>
5  *
6  * based in parts on Nook zforce driver
7  *
8  * Copyright (C) 2010 Barnes & Noble, Inc.
9  * Author: Pieter Truter<ptruter@intrinsyc.com>
10  */
11 
12 #include <linux/module.h>
13 #include <linux/hrtimer.h>
14 #include <linux/slab.h>
15 #include <linux/input.h>
16 #include <linux/interrupt.h>
17 #include <linux/i2c.h>
18 #include <linux/delay.h>
19 #include <linux/gpio/consumer.h>
20 #include <linux/device.h>
21 #include <linux/sysfs.h>
22 #include <linux/input/mt.h>
23 #include <linux/platform_data/zforce_ts.h>
24 #include <linux/regulator/consumer.h>
25 #include <linux/of.h>
26 
27 #define WAIT_TIMEOUT		msecs_to_jiffies(1000)
28 
29 #define FRAME_START		0xee
30 #define FRAME_MAXSIZE		257
31 
32 /* Offsets of the different parts of the payload the controller sends */
33 #define PAYLOAD_HEADER		0
34 #define PAYLOAD_LENGTH		1
35 #define PAYLOAD_BODY		2
36 
37 /* Response offsets */
38 #define RESPONSE_ID		0
39 #define RESPONSE_DATA		1
40 
41 /* Commands */
42 #define COMMAND_DEACTIVATE	0x00
43 #define COMMAND_INITIALIZE	0x01
44 #define COMMAND_RESOLUTION	0x02
45 #define COMMAND_SETCONFIG	0x03
46 #define COMMAND_DATAREQUEST	0x04
47 #define COMMAND_SCANFREQ	0x08
48 #define COMMAND_STATUS		0X1e
49 
50 /*
51  * Responses the controller sends as a result of
52  * command requests
53  */
54 #define RESPONSE_DEACTIVATE	0x00
55 #define RESPONSE_INITIALIZE	0x01
56 #define RESPONSE_RESOLUTION	0x02
57 #define RESPONSE_SETCONFIG	0x03
58 #define RESPONSE_SCANFREQ	0x08
59 #define RESPONSE_STATUS		0X1e
60 
61 /*
62  * Notifications are sent by the touch controller without
63  * being requested by the driver and include for example
64  * touch indications
65  */
66 #define NOTIFICATION_TOUCH		0x04
67 #define NOTIFICATION_BOOTCOMPLETE	0x07
68 #define NOTIFICATION_OVERRUN		0x25
69 #define NOTIFICATION_PROXIMITY		0x26
70 #define NOTIFICATION_INVALID_COMMAND	0xfe
71 
72 #define ZFORCE_REPORT_POINTS		2
73 #define ZFORCE_MAX_AREA			0xff
74 
75 #define STATE_DOWN			0
76 #define STATE_MOVE			1
77 #define STATE_UP			2
78 
79 #define SETCONFIG_DUALTOUCH		(1 << 0)
80 
81 struct zforce_point {
82 	int coord_x;
83 	int coord_y;
84 	int state;
85 	int id;
86 	int area_major;
87 	int area_minor;
88 	int orientation;
89 	int pressure;
90 	int prblty;
91 };
92 
93 /*
94  * @client		the i2c_client
95  * @input		the input device
96  * @suspending		in the process of going to suspend (don't emit wakeup
97  *			events for commands executed to suspend the device)
98  * @suspended		device suspended
99  * @access_mutex	serialize i2c-access, to keep multipart reads together
100  * @command_done	completion to wait for the command result
101  * @command_mutex	serialize commands sent to the ic
102  * @command_waiting	the id of the command that is currently waiting
103  *			for a result
104  * @command_result	returned result of the command
105  */
106 struct zforce_ts {
107 	struct i2c_client	*client;
108 	struct input_dev	*input;
109 	const struct zforce_ts_platdata *pdata;
110 	char			phys[32];
111 
112 	struct regulator	*reg_vdd;
113 
114 	struct gpio_desc	*gpio_int;
115 	struct gpio_desc	*gpio_rst;
116 
117 	bool			suspending;
118 	bool			suspended;
119 	bool			boot_complete;
120 
121 	/* Firmware version information */
122 	u16			version_major;
123 	u16			version_minor;
124 	u16			version_build;
125 	u16			version_rev;
126 
127 	struct mutex		access_mutex;
128 
129 	struct completion	command_done;
130 	struct mutex		command_mutex;
131 	int			command_waiting;
132 	int			command_result;
133 };
134 
135 static int zforce_command(struct zforce_ts *ts, u8 cmd)
136 {
137 	struct i2c_client *client = ts->client;
138 	char buf[3];
139 	int ret;
140 
141 	dev_dbg(&client->dev, "%s: 0x%x\n", __func__, cmd);
142 
143 	buf[0] = FRAME_START;
144 	buf[1] = 1; /* data size, command only */
145 	buf[2] = cmd;
146 
147 	mutex_lock(&ts->access_mutex);
148 	ret = i2c_master_send(client, &buf[0], ARRAY_SIZE(buf));
149 	mutex_unlock(&ts->access_mutex);
150 	if (ret < 0) {
151 		dev_err(&client->dev, "i2c send data request error: %d\n", ret);
152 		return ret;
153 	}
154 
155 	return 0;
156 }
157 
158 static void zforce_reset_assert(struct zforce_ts *ts)
159 {
160 	gpiod_set_value_cansleep(ts->gpio_rst, 1);
161 }
162 
163 static void zforce_reset_deassert(struct zforce_ts *ts)
164 {
165 	gpiod_set_value_cansleep(ts->gpio_rst, 0);
166 }
167 
168 static int zforce_send_wait(struct zforce_ts *ts, const char *buf, int len)
169 {
170 	struct i2c_client *client = ts->client;
171 	int ret;
172 
173 	ret = mutex_trylock(&ts->command_mutex);
174 	if (!ret) {
175 		dev_err(&client->dev, "already waiting for a command\n");
176 		return -EBUSY;
177 	}
178 
179 	dev_dbg(&client->dev, "sending %d bytes for command 0x%x\n",
180 		buf[1], buf[2]);
181 
182 	ts->command_waiting = buf[2];
183 
184 	mutex_lock(&ts->access_mutex);
185 	ret = i2c_master_send(client, buf, len);
186 	mutex_unlock(&ts->access_mutex);
187 	if (ret < 0) {
188 		dev_err(&client->dev, "i2c send data request error: %d\n", ret);
189 		goto unlock;
190 	}
191 
192 	dev_dbg(&client->dev, "waiting for result for command 0x%x\n", buf[2]);
193 
194 	if (wait_for_completion_timeout(&ts->command_done, WAIT_TIMEOUT) == 0) {
195 		ret = -ETIME;
196 		goto unlock;
197 	}
198 
199 	ret = ts->command_result;
200 
201 unlock:
202 	mutex_unlock(&ts->command_mutex);
203 	return ret;
204 }
205 
206 static int zforce_command_wait(struct zforce_ts *ts, u8 cmd)
207 {
208 	struct i2c_client *client = ts->client;
209 	char buf[3];
210 	int ret;
211 
212 	dev_dbg(&client->dev, "%s: 0x%x\n", __func__, cmd);
213 
214 	buf[0] = FRAME_START;
215 	buf[1] = 1; /* data size, command only */
216 	buf[2] = cmd;
217 
218 	ret = zforce_send_wait(ts, &buf[0], ARRAY_SIZE(buf));
219 	if (ret < 0) {
220 		dev_err(&client->dev, "i2c send data request error: %d\n", ret);
221 		return ret;
222 	}
223 
224 	return 0;
225 }
226 
227 static int zforce_resolution(struct zforce_ts *ts, u16 x, u16 y)
228 {
229 	struct i2c_client *client = ts->client;
230 	char buf[7] = { FRAME_START, 5, COMMAND_RESOLUTION,
231 			(x & 0xff), ((x >> 8) & 0xff),
232 			(y & 0xff), ((y >> 8) & 0xff) };
233 
234 	dev_dbg(&client->dev, "set resolution to (%d,%d)\n", x, y);
235 
236 	return zforce_send_wait(ts, &buf[0], ARRAY_SIZE(buf));
237 }
238 
239 static int zforce_scan_frequency(struct zforce_ts *ts, u16 idle, u16 finger,
240 				 u16 stylus)
241 {
242 	struct i2c_client *client = ts->client;
243 	char buf[9] = { FRAME_START, 7, COMMAND_SCANFREQ,
244 			(idle & 0xff), ((idle >> 8) & 0xff),
245 			(finger & 0xff), ((finger >> 8) & 0xff),
246 			(stylus & 0xff), ((stylus >> 8) & 0xff) };
247 
248 	dev_dbg(&client->dev,
249 		"set scan frequency to (idle: %d, finger: %d, stylus: %d)\n",
250 		idle, finger, stylus);
251 
252 	return zforce_send_wait(ts, &buf[0], ARRAY_SIZE(buf));
253 }
254 
255 static int zforce_setconfig(struct zforce_ts *ts, char b1)
256 {
257 	struct i2c_client *client = ts->client;
258 	char buf[7] = { FRAME_START, 5, COMMAND_SETCONFIG,
259 			b1, 0, 0, 0 };
260 
261 	dev_dbg(&client->dev, "set config to (%d)\n", b1);
262 
263 	return zforce_send_wait(ts, &buf[0], ARRAY_SIZE(buf));
264 }
265 
266 static int zforce_start(struct zforce_ts *ts)
267 {
268 	struct i2c_client *client = ts->client;
269 	const struct zforce_ts_platdata *pdata = ts->pdata;
270 	int ret;
271 
272 	dev_dbg(&client->dev, "starting device\n");
273 
274 	ret = zforce_command_wait(ts, COMMAND_INITIALIZE);
275 	if (ret) {
276 		dev_err(&client->dev, "Unable to initialize, %d\n", ret);
277 		return ret;
278 	}
279 
280 	ret = zforce_resolution(ts, pdata->x_max, pdata->y_max);
281 	if (ret) {
282 		dev_err(&client->dev, "Unable to set resolution, %d\n", ret);
283 		goto error;
284 	}
285 
286 	ret = zforce_scan_frequency(ts, 10, 50, 50);
287 	if (ret) {
288 		dev_err(&client->dev, "Unable to set scan frequency, %d\n",
289 			ret);
290 		goto error;
291 	}
292 
293 	ret = zforce_setconfig(ts, SETCONFIG_DUALTOUCH);
294 	if (ret) {
295 		dev_err(&client->dev, "Unable to set config\n");
296 		goto error;
297 	}
298 
299 	/* start sending touch events */
300 	ret = zforce_command(ts, COMMAND_DATAREQUEST);
301 	if (ret) {
302 		dev_err(&client->dev, "Unable to request data\n");
303 		goto error;
304 	}
305 
306 	/*
307 	 * Per NN, initial cal. take max. of 200msec.
308 	 * Allow time to complete this calibration
309 	 */
310 	msleep(200);
311 
312 	return 0;
313 
314 error:
315 	zforce_command_wait(ts, COMMAND_DEACTIVATE);
316 	return ret;
317 }
318 
319 static int zforce_stop(struct zforce_ts *ts)
320 {
321 	struct i2c_client *client = ts->client;
322 	int ret;
323 
324 	dev_dbg(&client->dev, "stopping device\n");
325 
326 	/* Deactivates touch sensing and puts the device into sleep. */
327 	ret = zforce_command_wait(ts, COMMAND_DEACTIVATE);
328 	if (ret != 0) {
329 		dev_err(&client->dev, "could not deactivate device, %d\n",
330 			ret);
331 		return ret;
332 	}
333 
334 	return 0;
335 }
336 
337 static int zforce_touch_event(struct zforce_ts *ts, u8 *payload)
338 {
339 	struct i2c_client *client = ts->client;
340 	const struct zforce_ts_platdata *pdata = ts->pdata;
341 	struct zforce_point point;
342 	int count, i, num = 0;
343 
344 	count = payload[0];
345 	if (count > ZFORCE_REPORT_POINTS) {
346 		dev_warn(&client->dev,
347 			 "too many coordinates %d, expected max %d\n",
348 			 count, ZFORCE_REPORT_POINTS);
349 		count = ZFORCE_REPORT_POINTS;
350 	}
351 
352 	for (i = 0; i < count; i++) {
353 		point.coord_x =
354 			payload[9 * i + 2] << 8 | payload[9 * i + 1];
355 		point.coord_y =
356 			payload[9 * i + 4] << 8 | payload[9 * i + 3];
357 
358 		if (point.coord_x > pdata->x_max ||
359 		    point.coord_y > pdata->y_max) {
360 			dev_warn(&client->dev, "coordinates (%d,%d) invalid\n",
361 				point.coord_x, point.coord_y);
362 			point.coord_x = point.coord_y = 0;
363 		}
364 
365 		point.state = payload[9 * i + 5] & 0x0f;
366 		point.id = (payload[9 * i + 5] & 0xf0) >> 4;
367 
368 		/* determine touch major, minor and orientation */
369 		point.area_major = max(payload[9 * i + 6],
370 					  payload[9 * i + 7]);
371 		point.area_minor = min(payload[9 * i + 6],
372 					  payload[9 * i + 7]);
373 		point.orientation = payload[9 * i + 6] > payload[9 * i + 7];
374 
375 		point.pressure = payload[9 * i + 8];
376 		point.prblty = payload[9 * i + 9];
377 
378 		dev_dbg(&client->dev,
379 			"point %d/%d: state %d, id %d, pressure %d, prblty %d, x %d, y %d, amajor %d, aminor %d, ori %d\n",
380 			i, count, point.state, point.id,
381 			point.pressure, point.prblty,
382 			point.coord_x, point.coord_y,
383 			point.area_major, point.area_minor,
384 			point.orientation);
385 
386 		/* the zforce id starts with "1", so needs to be decreased */
387 		input_mt_slot(ts->input, point.id - 1);
388 
389 		input_mt_report_slot_state(ts->input, MT_TOOL_FINGER,
390 						point.state != STATE_UP);
391 
392 		if (point.state != STATE_UP) {
393 			input_report_abs(ts->input, ABS_MT_POSITION_X,
394 					 point.coord_x);
395 			input_report_abs(ts->input, ABS_MT_POSITION_Y,
396 					 point.coord_y);
397 			input_report_abs(ts->input, ABS_MT_TOUCH_MAJOR,
398 					 point.area_major);
399 			input_report_abs(ts->input, ABS_MT_TOUCH_MINOR,
400 					 point.area_minor);
401 			input_report_abs(ts->input, ABS_MT_ORIENTATION,
402 					 point.orientation);
403 			num++;
404 		}
405 	}
406 
407 	input_mt_sync_frame(ts->input);
408 
409 	input_mt_report_finger_count(ts->input, num);
410 
411 	input_sync(ts->input);
412 
413 	return 0;
414 }
415 
416 static int zforce_read_packet(struct zforce_ts *ts, u8 *buf)
417 {
418 	struct i2c_client *client = ts->client;
419 	int ret;
420 
421 	mutex_lock(&ts->access_mutex);
422 
423 	/* read 2 byte message header */
424 	ret = i2c_master_recv(client, buf, 2);
425 	if (ret < 0) {
426 		dev_err(&client->dev, "error reading header: %d\n", ret);
427 		goto unlock;
428 	}
429 
430 	if (buf[PAYLOAD_HEADER] != FRAME_START) {
431 		dev_err(&client->dev, "invalid frame start: %d\n", buf[0]);
432 		ret = -EIO;
433 		goto unlock;
434 	}
435 
436 	if (buf[PAYLOAD_LENGTH] == 0) {
437 		dev_err(&client->dev, "invalid payload length: %d\n",
438 			buf[PAYLOAD_LENGTH]);
439 		ret = -EIO;
440 		goto unlock;
441 	}
442 
443 	/* read the message */
444 	ret = i2c_master_recv(client, &buf[PAYLOAD_BODY], buf[PAYLOAD_LENGTH]);
445 	if (ret < 0) {
446 		dev_err(&client->dev, "error reading payload: %d\n", ret);
447 		goto unlock;
448 	}
449 
450 	dev_dbg(&client->dev, "read %d bytes for response command 0x%x\n",
451 		buf[PAYLOAD_LENGTH], buf[PAYLOAD_BODY]);
452 
453 unlock:
454 	mutex_unlock(&ts->access_mutex);
455 	return ret;
456 }
457 
458 static void zforce_complete(struct zforce_ts *ts, int cmd, int result)
459 {
460 	struct i2c_client *client = ts->client;
461 
462 	if (ts->command_waiting == cmd) {
463 		dev_dbg(&client->dev, "completing command 0x%x\n", cmd);
464 		ts->command_result = result;
465 		complete(&ts->command_done);
466 	} else {
467 		dev_dbg(&client->dev, "command %d not for us\n", cmd);
468 	}
469 }
470 
471 static irqreturn_t zforce_irq(int irq, void *dev_id)
472 {
473 	struct zforce_ts *ts = dev_id;
474 	struct i2c_client *client = ts->client;
475 
476 	if (ts->suspended && device_may_wakeup(&client->dev))
477 		pm_wakeup_event(&client->dev, 500);
478 
479 	return IRQ_WAKE_THREAD;
480 }
481 
482 static irqreturn_t zforce_irq_thread(int irq, void *dev_id)
483 {
484 	struct zforce_ts *ts = dev_id;
485 	struct i2c_client *client = ts->client;
486 	int ret;
487 	u8 payload_buffer[FRAME_MAXSIZE];
488 	u8 *payload;
489 
490 	/*
491 	 * When still suspended, return.
492 	 * Due to the level-interrupt we will get re-triggered later.
493 	 */
494 	if (ts->suspended) {
495 		msleep(20);
496 		return IRQ_HANDLED;
497 	}
498 
499 	dev_dbg(&client->dev, "handling interrupt\n");
500 
501 	/* Don't emit wakeup events from commands run by zforce_suspend */
502 	if (!ts->suspending && device_may_wakeup(&client->dev))
503 		pm_stay_awake(&client->dev);
504 
505 	/*
506 	 * Run at least once and exit the loop if
507 	 * - the optional interrupt GPIO isn't specified
508 	 *   (there is only one packet read per ISR invocation, then)
509 	 * or
510 	 * - the GPIO isn't active any more
511 	 *   (packet read until the level GPIO indicates that there is
512 	 *    no IRQ any more)
513 	 */
514 	do {
515 		ret = zforce_read_packet(ts, payload_buffer);
516 		if (ret < 0) {
517 			dev_err(&client->dev,
518 				"could not read packet, ret: %d\n", ret);
519 			break;
520 		}
521 
522 		payload =  &payload_buffer[PAYLOAD_BODY];
523 
524 		switch (payload[RESPONSE_ID]) {
525 		case NOTIFICATION_TOUCH:
526 			/*
527 			 * Always report touch-events received while
528 			 * suspending, when being a wakeup source
529 			 */
530 			if (ts->suspending && device_may_wakeup(&client->dev))
531 				pm_wakeup_event(&client->dev, 500);
532 			zforce_touch_event(ts, &payload[RESPONSE_DATA]);
533 			break;
534 
535 		case NOTIFICATION_BOOTCOMPLETE:
536 			ts->boot_complete = payload[RESPONSE_DATA];
537 			zforce_complete(ts, payload[RESPONSE_ID], 0);
538 			break;
539 
540 		case RESPONSE_INITIALIZE:
541 		case RESPONSE_DEACTIVATE:
542 		case RESPONSE_SETCONFIG:
543 		case RESPONSE_RESOLUTION:
544 		case RESPONSE_SCANFREQ:
545 			zforce_complete(ts, payload[RESPONSE_ID],
546 					payload[RESPONSE_DATA]);
547 			break;
548 
549 		case RESPONSE_STATUS:
550 			/*
551 			 * Version Payload Results
552 			 * [2:major] [2:minor] [2:build] [2:rev]
553 			 */
554 			ts->version_major = (payload[RESPONSE_DATA + 1] << 8) |
555 						payload[RESPONSE_DATA];
556 			ts->version_minor = (payload[RESPONSE_DATA + 3] << 8) |
557 						payload[RESPONSE_DATA + 2];
558 			ts->version_build = (payload[RESPONSE_DATA + 5] << 8) |
559 						payload[RESPONSE_DATA + 4];
560 			ts->version_rev   = (payload[RESPONSE_DATA + 7] << 8) |
561 						payload[RESPONSE_DATA + 6];
562 			dev_dbg(&ts->client->dev,
563 				"Firmware Version %04x:%04x %04x:%04x\n",
564 				ts->version_major, ts->version_minor,
565 				ts->version_build, ts->version_rev);
566 
567 			zforce_complete(ts, payload[RESPONSE_ID], 0);
568 			break;
569 
570 		case NOTIFICATION_INVALID_COMMAND:
571 			dev_err(&ts->client->dev, "invalid command: 0x%x\n",
572 				payload[RESPONSE_DATA]);
573 			break;
574 
575 		default:
576 			dev_err(&ts->client->dev,
577 				"unrecognized response id: 0x%x\n",
578 				payload[RESPONSE_ID]);
579 			break;
580 		}
581 	} while (gpiod_get_value_cansleep(ts->gpio_int));
582 
583 	if (!ts->suspending && device_may_wakeup(&client->dev))
584 		pm_relax(&client->dev);
585 
586 	dev_dbg(&client->dev, "finished interrupt\n");
587 
588 	return IRQ_HANDLED;
589 }
590 
591 static int zforce_input_open(struct input_dev *dev)
592 {
593 	struct zforce_ts *ts = input_get_drvdata(dev);
594 
595 	return zforce_start(ts);
596 }
597 
598 static void zforce_input_close(struct input_dev *dev)
599 {
600 	struct zforce_ts *ts = input_get_drvdata(dev);
601 	struct i2c_client *client = ts->client;
602 	int ret;
603 
604 	ret = zforce_stop(ts);
605 	if (ret)
606 		dev_warn(&client->dev, "stopping zforce failed\n");
607 
608 	return;
609 }
610 
611 static int __maybe_unused zforce_suspend(struct device *dev)
612 {
613 	struct i2c_client *client = to_i2c_client(dev);
614 	struct zforce_ts *ts = i2c_get_clientdata(client);
615 	struct input_dev *input = ts->input;
616 	int ret = 0;
617 
618 	mutex_lock(&input->mutex);
619 	ts->suspending = true;
620 
621 	/*
622 	 * When configured as a wakeup source device should always wake
623 	 * the system, therefore start device if necessary.
624 	 */
625 	if (device_may_wakeup(&client->dev)) {
626 		dev_dbg(&client->dev, "suspend while being a wakeup source\n");
627 
628 		/* Need to start device, if not open, to be a wakeup source. */
629 		if (!input_device_enabled(input)) {
630 			ret = zforce_start(ts);
631 			if (ret)
632 				goto unlock;
633 		}
634 
635 		enable_irq_wake(client->irq);
636 	} else if (input_device_enabled(input)) {
637 		dev_dbg(&client->dev,
638 			"suspend without being a wakeup source\n");
639 
640 		ret = zforce_stop(ts);
641 		if (ret)
642 			goto unlock;
643 
644 		disable_irq(client->irq);
645 	}
646 
647 	ts->suspended = true;
648 
649 unlock:
650 	ts->suspending = false;
651 	mutex_unlock(&input->mutex);
652 
653 	return ret;
654 }
655 
656 static int __maybe_unused zforce_resume(struct device *dev)
657 {
658 	struct i2c_client *client = to_i2c_client(dev);
659 	struct zforce_ts *ts = i2c_get_clientdata(client);
660 	struct input_dev *input = ts->input;
661 	int ret = 0;
662 
663 	mutex_lock(&input->mutex);
664 
665 	ts->suspended = false;
666 
667 	if (device_may_wakeup(&client->dev)) {
668 		dev_dbg(&client->dev, "resume from being a wakeup source\n");
669 
670 		disable_irq_wake(client->irq);
671 
672 		/* need to stop device if it was not open on suspend */
673 		if (!input_device_enabled(input)) {
674 			ret = zforce_stop(ts);
675 			if (ret)
676 				goto unlock;
677 		}
678 	} else if (input_device_enabled(input)) {
679 		dev_dbg(&client->dev, "resume without being a wakeup source\n");
680 
681 		enable_irq(client->irq);
682 
683 		ret = zforce_start(ts);
684 		if (ret < 0)
685 			goto unlock;
686 	}
687 
688 unlock:
689 	mutex_unlock(&input->mutex);
690 
691 	return ret;
692 }
693 
694 static SIMPLE_DEV_PM_OPS(zforce_pm_ops, zforce_suspend, zforce_resume);
695 
696 static void zforce_reset(void *data)
697 {
698 	struct zforce_ts *ts = data;
699 
700 	zforce_reset_assert(ts);
701 
702 	udelay(10);
703 
704 	if (!IS_ERR(ts->reg_vdd))
705 		regulator_disable(ts->reg_vdd);
706 }
707 
708 static struct zforce_ts_platdata *zforce_parse_dt(struct device *dev)
709 {
710 	struct zforce_ts_platdata *pdata;
711 	struct device_node *np = dev->of_node;
712 
713 	if (!np)
714 		return ERR_PTR(-ENOENT);
715 
716 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
717 	if (!pdata) {
718 		dev_err(dev, "failed to allocate platform data\n");
719 		return ERR_PTR(-ENOMEM);
720 	}
721 
722 	if (of_property_read_u32(np, "x-size", &pdata->x_max)) {
723 		dev_err(dev, "failed to get x-size property\n");
724 		return ERR_PTR(-EINVAL);
725 	}
726 
727 	if (of_property_read_u32(np, "y-size", &pdata->y_max)) {
728 		dev_err(dev, "failed to get y-size property\n");
729 		return ERR_PTR(-EINVAL);
730 	}
731 
732 	return pdata;
733 }
734 
735 static int zforce_probe(struct i2c_client *client,
736 			const struct i2c_device_id *id)
737 {
738 	const struct zforce_ts_platdata *pdata = dev_get_platdata(&client->dev);
739 	struct zforce_ts *ts;
740 	struct input_dev *input_dev;
741 	int ret;
742 
743 	if (!pdata) {
744 		pdata = zforce_parse_dt(&client->dev);
745 		if (IS_ERR(pdata))
746 			return PTR_ERR(pdata);
747 	}
748 
749 	ts = devm_kzalloc(&client->dev, sizeof(struct zforce_ts), GFP_KERNEL);
750 	if (!ts)
751 		return -ENOMEM;
752 
753 	ts->gpio_rst = devm_gpiod_get_optional(&client->dev, "reset",
754 					       GPIOD_OUT_HIGH);
755 	if (IS_ERR(ts->gpio_rst)) {
756 		ret = PTR_ERR(ts->gpio_rst);
757 		dev_err(&client->dev,
758 			"failed to request reset GPIO: %d\n", ret);
759 		return ret;
760 	}
761 
762 	if (ts->gpio_rst) {
763 		ts->gpio_int = devm_gpiod_get_optional(&client->dev, "irq",
764 						       GPIOD_IN);
765 		if (IS_ERR(ts->gpio_int)) {
766 			ret = PTR_ERR(ts->gpio_int);
767 			dev_err(&client->dev,
768 				"failed to request interrupt GPIO: %d\n", ret);
769 			return ret;
770 		}
771 	} else {
772 		/*
773 		 * Deprecated GPIO handling for compatibility
774 		 * with legacy binding.
775 		 */
776 
777 		/* INT GPIO */
778 		ts->gpio_int = devm_gpiod_get_index(&client->dev, NULL, 0,
779 						    GPIOD_IN);
780 		if (IS_ERR(ts->gpio_int)) {
781 			ret = PTR_ERR(ts->gpio_int);
782 			dev_err(&client->dev,
783 				"failed to request interrupt GPIO: %d\n", ret);
784 			return ret;
785 		}
786 
787 		/* RST GPIO */
788 		ts->gpio_rst = devm_gpiod_get_index(&client->dev, NULL, 1,
789 					    GPIOD_OUT_HIGH);
790 		if (IS_ERR(ts->gpio_rst)) {
791 			ret = PTR_ERR(ts->gpio_rst);
792 			dev_err(&client->dev,
793 				"failed to request reset GPIO: %d\n", ret);
794 			return ret;
795 		}
796 	}
797 
798 	ts->reg_vdd = devm_regulator_get_optional(&client->dev, "vdd");
799 	if (IS_ERR(ts->reg_vdd)) {
800 		ret = PTR_ERR(ts->reg_vdd);
801 		if (ret == -EPROBE_DEFER)
802 			return ret;
803 	} else {
804 		ret = regulator_enable(ts->reg_vdd);
805 		if (ret)
806 			return ret;
807 
808 		/*
809 		 * according to datasheet add 100us grace time after regular
810 		 * regulator enable delay.
811 		 */
812 		udelay(100);
813 	}
814 
815 	ret = devm_add_action(&client->dev, zforce_reset, ts);
816 	if (ret) {
817 		dev_err(&client->dev, "failed to register reset action, %d\n",
818 			ret);
819 
820 		/* hereafter the regulator will be disabled by the action */
821 		if (!IS_ERR(ts->reg_vdd))
822 			regulator_disable(ts->reg_vdd);
823 
824 		return ret;
825 	}
826 
827 	snprintf(ts->phys, sizeof(ts->phys),
828 		 "%s/input0", dev_name(&client->dev));
829 
830 	input_dev = devm_input_allocate_device(&client->dev);
831 	if (!input_dev) {
832 		dev_err(&client->dev, "could not allocate input device\n");
833 		return -ENOMEM;
834 	}
835 
836 	mutex_init(&ts->access_mutex);
837 	mutex_init(&ts->command_mutex);
838 
839 	ts->pdata = pdata;
840 	ts->client = client;
841 	ts->input = input_dev;
842 
843 	input_dev->name = "Neonode zForce touchscreen";
844 	input_dev->phys = ts->phys;
845 	input_dev->id.bustype = BUS_I2C;
846 
847 	input_dev->open = zforce_input_open;
848 	input_dev->close = zforce_input_close;
849 
850 	__set_bit(EV_KEY, input_dev->evbit);
851 	__set_bit(EV_SYN, input_dev->evbit);
852 	__set_bit(EV_ABS, input_dev->evbit);
853 
854 	/* For multi touch */
855 	input_set_abs_params(input_dev, ABS_MT_POSITION_X, 0,
856 			     pdata->x_max, 0, 0);
857 	input_set_abs_params(input_dev, ABS_MT_POSITION_Y, 0,
858 			     pdata->y_max, 0, 0);
859 
860 	input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0,
861 			     ZFORCE_MAX_AREA, 0, 0);
862 	input_set_abs_params(input_dev, ABS_MT_TOUCH_MINOR, 0,
863 			     ZFORCE_MAX_AREA, 0, 0);
864 	input_set_abs_params(input_dev, ABS_MT_ORIENTATION, 0, 1, 0, 0);
865 	input_mt_init_slots(input_dev, ZFORCE_REPORT_POINTS, INPUT_MT_DIRECT);
866 
867 	input_set_drvdata(ts->input, ts);
868 
869 	init_completion(&ts->command_done);
870 
871 	/*
872 	 * The zforce pulls the interrupt low when it has data ready.
873 	 * After it is triggered the isr thread runs until all the available
874 	 * packets have been read and the interrupt is high again.
875 	 * Therefore we can trigger the interrupt anytime it is low and do
876 	 * not need to limit it to the interrupt edge.
877 	 */
878 	ret = devm_request_threaded_irq(&client->dev, client->irq,
879 					zforce_irq, zforce_irq_thread,
880 					IRQF_TRIGGER_LOW | IRQF_ONESHOT,
881 					input_dev->name, ts);
882 	if (ret) {
883 		dev_err(&client->dev, "irq %d request failed\n", client->irq);
884 		return ret;
885 	}
886 
887 	i2c_set_clientdata(client, ts);
888 
889 	/* let the controller boot */
890 	zforce_reset_deassert(ts);
891 
892 	ts->command_waiting = NOTIFICATION_BOOTCOMPLETE;
893 	if (wait_for_completion_timeout(&ts->command_done, WAIT_TIMEOUT) == 0)
894 		dev_warn(&client->dev, "bootcomplete timed out\n");
895 
896 	/* need to start device to get version information */
897 	ret = zforce_command_wait(ts, COMMAND_INITIALIZE);
898 	if (ret) {
899 		dev_err(&client->dev, "unable to initialize, %d\n", ret);
900 		return ret;
901 	}
902 
903 	/* this gets the firmware version among other information */
904 	ret = zforce_command_wait(ts, COMMAND_STATUS);
905 	if (ret < 0) {
906 		dev_err(&client->dev, "couldn't get status, %d\n", ret);
907 		zforce_stop(ts);
908 		return ret;
909 	}
910 
911 	/* stop device and put it into sleep until it is opened */
912 	ret = zforce_stop(ts);
913 	if (ret < 0)
914 		return ret;
915 
916 	device_set_wakeup_capable(&client->dev, true);
917 
918 	ret = input_register_device(input_dev);
919 	if (ret) {
920 		dev_err(&client->dev, "could not register input device, %d\n",
921 			ret);
922 		return ret;
923 	}
924 
925 	return 0;
926 }
927 
928 static struct i2c_device_id zforce_idtable[] = {
929 	{ "zforce-ts", 0 },
930 	{ }
931 };
932 MODULE_DEVICE_TABLE(i2c, zforce_idtable);
933 
934 #ifdef CONFIG_OF
935 static const struct of_device_id zforce_dt_idtable[] = {
936 	{ .compatible = "neonode,zforce" },
937 	{},
938 };
939 MODULE_DEVICE_TABLE(of, zforce_dt_idtable);
940 #endif
941 
942 static struct i2c_driver zforce_driver = {
943 	.driver = {
944 		.name	= "zforce-ts",
945 		.pm	= &zforce_pm_ops,
946 		.of_match_table	= of_match_ptr(zforce_dt_idtable),
947 	},
948 	.probe		= zforce_probe,
949 	.id_table	= zforce_idtable,
950 };
951 
952 module_i2c_driver(zforce_driver);
953 
954 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
955 MODULE_DESCRIPTION("zForce TouchScreen Driver");
956 MODULE_LICENSE("GPL");
957