1 /*
2  * Copyright (C) 2012-2013 MundoReader S.L.
3  * Author: Heiko Stuebner <heiko@sntech.de>
4  *
5  * based in parts on Nook zforce driver
6  *
7  * Copyright (C) 2010 Barnes & Noble, Inc.
8  * Author: Pieter Truter<ptruter@intrinsyc.com>
9  *
10  * This software is licensed under the terms of the GNU General Public
11  * License version 2, as published by the Free Software Foundation, and
12  * may be copied, distributed, and modified under those terms.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  * GNU General Public License for more details.
18  */
19 
20 #include <linux/module.h>
21 #include <linux/hrtimer.h>
22 #include <linux/slab.h>
23 #include <linux/input.h>
24 #include <linux/interrupt.h>
25 #include <linux/i2c.h>
26 #include <linux/delay.h>
27 #include <linux/gpio/consumer.h>
28 #include <linux/device.h>
29 #include <linux/sysfs.h>
30 #include <linux/input/mt.h>
31 #include <linux/platform_data/zforce_ts.h>
32 #include <linux/regulator/consumer.h>
33 #include <linux/of.h>
34 
35 #define WAIT_TIMEOUT		msecs_to_jiffies(1000)
36 
37 #define FRAME_START		0xee
38 #define FRAME_MAXSIZE		257
39 
40 /* Offsets of the different parts of the payload the controller sends */
41 #define PAYLOAD_HEADER		0
42 #define PAYLOAD_LENGTH		1
43 #define PAYLOAD_BODY		2
44 
45 /* Response offsets */
46 #define RESPONSE_ID		0
47 #define RESPONSE_DATA		1
48 
49 /* Commands */
50 #define COMMAND_DEACTIVATE	0x00
51 #define COMMAND_INITIALIZE	0x01
52 #define COMMAND_RESOLUTION	0x02
53 #define COMMAND_SETCONFIG	0x03
54 #define COMMAND_DATAREQUEST	0x04
55 #define COMMAND_SCANFREQ	0x08
56 #define COMMAND_STATUS		0X1e
57 
58 /*
59  * Responses the controller sends as a result of
60  * command requests
61  */
62 #define RESPONSE_DEACTIVATE	0x00
63 #define RESPONSE_INITIALIZE	0x01
64 #define RESPONSE_RESOLUTION	0x02
65 #define RESPONSE_SETCONFIG	0x03
66 #define RESPONSE_SCANFREQ	0x08
67 #define RESPONSE_STATUS		0X1e
68 
69 /*
70  * Notifications are sent by the touch controller without
71  * being requested by the driver and include for example
72  * touch indications
73  */
74 #define NOTIFICATION_TOUCH		0x04
75 #define NOTIFICATION_BOOTCOMPLETE	0x07
76 #define NOTIFICATION_OVERRUN		0x25
77 #define NOTIFICATION_PROXIMITY		0x26
78 #define NOTIFICATION_INVALID_COMMAND	0xfe
79 
80 #define ZFORCE_REPORT_POINTS		2
81 #define ZFORCE_MAX_AREA			0xff
82 
83 #define STATE_DOWN			0
84 #define STATE_MOVE			1
85 #define STATE_UP			2
86 
87 #define SETCONFIG_DUALTOUCH		(1 << 0)
88 
89 struct zforce_point {
90 	int coord_x;
91 	int coord_y;
92 	int state;
93 	int id;
94 	int area_major;
95 	int area_minor;
96 	int orientation;
97 	int pressure;
98 	int prblty;
99 };
100 
101 /*
102  * @client		the i2c_client
103  * @input		the input device
104  * @suspending		in the process of going to suspend (don't emit wakeup
105  *			events for commands executed to suspend the device)
106  * @suspended		device suspended
107  * @access_mutex	serialize i2c-access, to keep multipart reads together
108  * @command_done	completion to wait for the command result
109  * @command_mutex	serialize commands sent to the ic
110  * @command_waiting	the id of the command that is currently waiting
111  *			for a result
112  * @command_result	returned result of the command
113  */
114 struct zforce_ts {
115 	struct i2c_client	*client;
116 	struct input_dev	*input;
117 	const struct zforce_ts_platdata *pdata;
118 	char			phys[32];
119 
120 	struct regulator	*reg_vdd;
121 
122 	struct gpio_desc	*gpio_int;
123 	struct gpio_desc	*gpio_rst;
124 
125 	bool			suspending;
126 	bool			suspended;
127 	bool			boot_complete;
128 
129 	/* Firmware version information */
130 	u16			version_major;
131 	u16			version_minor;
132 	u16			version_build;
133 	u16			version_rev;
134 
135 	struct mutex		access_mutex;
136 
137 	struct completion	command_done;
138 	struct mutex		command_mutex;
139 	int			command_waiting;
140 	int			command_result;
141 };
142 
143 static int zforce_command(struct zforce_ts *ts, u8 cmd)
144 {
145 	struct i2c_client *client = ts->client;
146 	char buf[3];
147 	int ret;
148 
149 	dev_dbg(&client->dev, "%s: 0x%x\n", __func__, cmd);
150 
151 	buf[0] = FRAME_START;
152 	buf[1] = 1; /* data size, command only */
153 	buf[2] = cmd;
154 
155 	mutex_lock(&ts->access_mutex);
156 	ret = i2c_master_send(client, &buf[0], ARRAY_SIZE(buf));
157 	mutex_unlock(&ts->access_mutex);
158 	if (ret < 0) {
159 		dev_err(&client->dev, "i2c send data request error: %d\n", ret);
160 		return ret;
161 	}
162 
163 	return 0;
164 }
165 
166 static void zforce_reset_assert(struct zforce_ts *ts)
167 {
168 	gpiod_set_value_cansleep(ts->gpio_rst, 1);
169 }
170 
171 static void zforce_reset_deassert(struct zforce_ts *ts)
172 {
173 	gpiod_set_value_cansleep(ts->gpio_rst, 0);
174 }
175 
176 static int zforce_send_wait(struct zforce_ts *ts, const char *buf, int len)
177 {
178 	struct i2c_client *client = ts->client;
179 	int ret;
180 
181 	ret = mutex_trylock(&ts->command_mutex);
182 	if (!ret) {
183 		dev_err(&client->dev, "already waiting for a command\n");
184 		return -EBUSY;
185 	}
186 
187 	dev_dbg(&client->dev, "sending %d bytes for command 0x%x\n",
188 		buf[1], buf[2]);
189 
190 	ts->command_waiting = buf[2];
191 
192 	mutex_lock(&ts->access_mutex);
193 	ret = i2c_master_send(client, buf, len);
194 	mutex_unlock(&ts->access_mutex);
195 	if (ret < 0) {
196 		dev_err(&client->dev, "i2c send data request error: %d\n", ret);
197 		goto unlock;
198 	}
199 
200 	dev_dbg(&client->dev, "waiting for result for command 0x%x\n", buf[2]);
201 
202 	if (wait_for_completion_timeout(&ts->command_done, WAIT_TIMEOUT) == 0) {
203 		ret = -ETIME;
204 		goto unlock;
205 	}
206 
207 	ret = ts->command_result;
208 
209 unlock:
210 	mutex_unlock(&ts->command_mutex);
211 	return ret;
212 }
213 
214 static int zforce_command_wait(struct zforce_ts *ts, u8 cmd)
215 {
216 	struct i2c_client *client = ts->client;
217 	char buf[3];
218 	int ret;
219 
220 	dev_dbg(&client->dev, "%s: 0x%x\n", __func__, cmd);
221 
222 	buf[0] = FRAME_START;
223 	buf[1] = 1; /* data size, command only */
224 	buf[2] = cmd;
225 
226 	ret = zforce_send_wait(ts, &buf[0], ARRAY_SIZE(buf));
227 	if (ret < 0) {
228 		dev_err(&client->dev, "i2c send data request error: %d\n", ret);
229 		return ret;
230 	}
231 
232 	return 0;
233 }
234 
235 static int zforce_resolution(struct zforce_ts *ts, u16 x, u16 y)
236 {
237 	struct i2c_client *client = ts->client;
238 	char buf[7] = { FRAME_START, 5, COMMAND_RESOLUTION,
239 			(x & 0xff), ((x >> 8) & 0xff),
240 			(y & 0xff), ((y >> 8) & 0xff) };
241 
242 	dev_dbg(&client->dev, "set resolution to (%d,%d)\n", x, y);
243 
244 	return zforce_send_wait(ts, &buf[0], ARRAY_SIZE(buf));
245 }
246 
247 static int zforce_scan_frequency(struct zforce_ts *ts, u16 idle, u16 finger,
248 				 u16 stylus)
249 {
250 	struct i2c_client *client = ts->client;
251 	char buf[9] = { FRAME_START, 7, COMMAND_SCANFREQ,
252 			(idle & 0xff), ((idle >> 8) & 0xff),
253 			(finger & 0xff), ((finger >> 8) & 0xff),
254 			(stylus & 0xff), ((stylus >> 8) & 0xff) };
255 
256 	dev_dbg(&client->dev,
257 		"set scan frequency to (idle: %d, finger: %d, stylus: %d)\n",
258 		idle, finger, stylus);
259 
260 	return zforce_send_wait(ts, &buf[0], ARRAY_SIZE(buf));
261 }
262 
263 static int zforce_setconfig(struct zforce_ts *ts, char b1)
264 {
265 	struct i2c_client *client = ts->client;
266 	char buf[7] = { FRAME_START, 5, COMMAND_SETCONFIG,
267 			b1, 0, 0, 0 };
268 
269 	dev_dbg(&client->dev, "set config to (%d)\n", b1);
270 
271 	return zforce_send_wait(ts, &buf[0], ARRAY_SIZE(buf));
272 }
273 
274 static int zforce_start(struct zforce_ts *ts)
275 {
276 	struct i2c_client *client = ts->client;
277 	const struct zforce_ts_platdata *pdata = ts->pdata;
278 	int ret;
279 
280 	dev_dbg(&client->dev, "starting device\n");
281 
282 	ret = zforce_command_wait(ts, COMMAND_INITIALIZE);
283 	if (ret) {
284 		dev_err(&client->dev, "Unable to initialize, %d\n", ret);
285 		return ret;
286 	}
287 
288 	ret = zforce_resolution(ts, pdata->x_max, pdata->y_max);
289 	if (ret) {
290 		dev_err(&client->dev, "Unable to set resolution, %d\n", ret);
291 		goto error;
292 	}
293 
294 	ret = zforce_scan_frequency(ts, 10, 50, 50);
295 	if (ret) {
296 		dev_err(&client->dev, "Unable to set scan frequency, %d\n",
297 			ret);
298 		goto error;
299 	}
300 
301 	ret = zforce_setconfig(ts, SETCONFIG_DUALTOUCH);
302 	if (ret) {
303 		dev_err(&client->dev, "Unable to set config\n");
304 		goto error;
305 	}
306 
307 	/* start sending touch events */
308 	ret = zforce_command(ts, COMMAND_DATAREQUEST);
309 	if (ret) {
310 		dev_err(&client->dev, "Unable to request data\n");
311 		goto error;
312 	}
313 
314 	/*
315 	 * Per NN, initial cal. take max. of 200msec.
316 	 * Allow time to complete this calibration
317 	 */
318 	msleep(200);
319 
320 	return 0;
321 
322 error:
323 	zforce_command_wait(ts, COMMAND_DEACTIVATE);
324 	return ret;
325 }
326 
327 static int zforce_stop(struct zforce_ts *ts)
328 {
329 	struct i2c_client *client = ts->client;
330 	int ret;
331 
332 	dev_dbg(&client->dev, "stopping device\n");
333 
334 	/* Deactivates touch sensing and puts the device into sleep. */
335 	ret = zforce_command_wait(ts, COMMAND_DEACTIVATE);
336 	if (ret != 0) {
337 		dev_err(&client->dev, "could not deactivate device, %d\n",
338 			ret);
339 		return ret;
340 	}
341 
342 	return 0;
343 }
344 
345 static int zforce_touch_event(struct zforce_ts *ts, u8 *payload)
346 {
347 	struct i2c_client *client = ts->client;
348 	const struct zforce_ts_platdata *pdata = ts->pdata;
349 	struct zforce_point point;
350 	int count, i, num = 0;
351 
352 	count = payload[0];
353 	if (count > ZFORCE_REPORT_POINTS) {
354 		dev_warn(&client->dev,
355 			 "too many coordinates %d, expected max %d\n",
356 			 count, ZFORCE_REPORT_POINTS);
357 		count = ZFORCE_REPORT_POINTS;
358 	}
359 
360 	for (i = 0; i < count; i++) {
361 		point.coord_x =
362 			payload[9 * i + 2] << 8 | payload[9 * i + 1];
363 		point.coord_y =
364 			payload[9 * i + 4] << 8 | payload[9 * i + 3];
365 
366 		if (point.coord_x > pdata->x_max ||
367 		    point.coord_y > pdata->y_max) {
368 			dev_warn(&client->dev, "coordinates (%d,%d) invalid\n",
369 				point.coord_x, point.coord_y);
370 			point.coord_x = point.coord_y = 0;
371 		}
372 
373 		point.state = payload[9 * i + 5] & 0x03;
374 		point.id = (payload[9 * i + 5] & 0xfc) >> 2;
375 
376 		/* determine touch major, minor and orientation */
377 		point.area_major = max(payload[9 * i + 6],
378 					  payload[9 * i + 7]);
379 		point.area_minor = min(payload[9 * i + 6],
380 					  payload[9 * i + 7]);
381 		point.orientation = payload[9 * i + 6] > payload[9 * i + 7];
382 
383 		point.pressure = payload[9 * i + 8];
384 		point.prblty = payload[9 * i + 9];
385 
386 		dev_dbg(&client->dev,
387 			"point %d/%d: state %d, id %d, pressure %d, prblty %d, x %d, y %d, amajor %d, aminor %d, ori %d\n",
388 			i, count, point.state, point.id,
389 			point.pressure, point.prblty,
390 			point.coord_x, point.coord_y,
391 			point.area_major, point.area_minor,
392 			point.orientation);
393 
394 		/* the zforce id starts with "1", so needs to be decreased */
395 		input_mt_slot(ts->input, point.id - 1);
396 
397 		input_mt_report_slot_state(ts->input, MT_TOOL_FINGER,
398 						point.state != STATE_UP);
399 
400 		if (point.state != STATE_UP) {
401 			input_report_abs(ts->input, ABS_MT_POSITION_X,
402 					 point.coord_x);
403 			input_report_abs(ts->input, ABS_MT_POSITION_Y,
404 					 point.coord_y);
405 			input_report_abs(ts->input, ABS_MT_TOUCH_MAJOR,
406 					 point.area_major);
407 			input_report_abs(ts->input, ABS_MT_TOUCH_MINOR,
408 					 point.area_minor);
409 			input_report_abs(ts->input, ABS_MT_ORIENTATION,
410 					 point.orientation);
411 			num++;
412 		}
413 	}
414 
415 	input_mt_sync_frame(ts->input);
416 
417 	input_mt_report_finger_count(ts->input, num);
418 
419 	input_sync(ts->input);
420 
421 	return 0;
422 }
423 
424 static int zforce_read_packet(struct zforce_ts *ts, u8 *buf)
425 {
426 	struct i2c_client *client = ts->client;
427 	int ret;
428 
429 	mutex_lock(&ts->access_mutex);
430 
431 	/* read 2 byte message header */
432 	ret = i2c_master_recv(client, buf, 2);
433 	if (ret < 0) {
434 		dev_err(&client->dev, "error reading header: %d\n", ret);
435 		goto unlock;
436 	}
437 
438 	if (buf[PAYLOAD_HEADER] != FRAME_START) {
439 		dev_err(&client->dev, "invalid frame start: %d\n", buf[0]);
440 		ret = -EIO;
441 		goto unlock;
442 	}
443 
444 	if (buf[PAYLOAD_LENGTH] == 0) {
445 		dev_err(&client->dev, "invalid payload length: %d\n",
446 			buf[PAYLOAD_LENGTH]);
447 		ret = -EIO;
448 		goto unlock;
449 	}
450 
451 	/* read the message */
452 	ret = i2c_master_recv(client, &buf[PAYLOAD_BODY], buf[PAYLOAD_LENGTH]);
453 	if (ret < 0) {
454 		dev_err(&client->dev, "error reading payload: %d\n", ret);
455 		goto unlock;
456 	}
457 
458 	dev_dbg(&client->dev, "read %d bytes for response command 0x%x\n",
459 		buf[PAYLOAD_LENGTH], buf[PAYLOAD_BODY]);
460 
461 unlock:
462 	mutex_unlock(&ts->access_mutex);
463 	return ret;
464 }
465 
466 static void zforce_complete(struct zforce_ts *ts, int cmd, int result)
467 {
468 	struct i2c_client *client = ts->client;
469 
470 	if (ts->command_waiting == cmd) {
471 		dev_dbg(&client->dev, "completing command 0x%x\n", cmd);
472 		ts->command_result = result;
473 		complete(&ts->command_done);
474 	} else {
475 		dev_dbg(&client->dev, "command %d not for us\n", cmd);
476 	}
477 }
478 
479 static irqreturn_t zforce_irq(int irq, void *dev_id)
480 {
481 	struct zforce_ts *ts = dev_id;
482 	struct i2c_client *client = ts->client;
483 
484 	if (ts->suspended && device_may_wakeup(&client->dev))
485 		pm_wakeup_event(&client->dev, 500);
486 
487 	return IRQ_WAKE_THREAD;
488 }
489 
490 static irqreturn_t zforce_irq_thread(int irq, void *dev_id)
491 {
492 	struct zforce_ts *ts = dev_id;
493 	struct i2c_client *client = ts->client;
494 	int ret;
495 	u8 payload_buffer[FRAME_MAXSIZE];
496 	u8 *payload;
497 
498 	/*
499 	 * When still suspended, return.
500 	 * Due to the level-interrupt we will get re-triggered later.
501 	 */
502 	if (ts->suspended) {
503 		msleep(20);
504 		return IRQ_HANDLED;
505 	}
506 
507 	dev_dbg(&client->dev, "handling interrupt\n");
508 
509 	/* Don't emit wakeup events from commands run by zforce_suspend */
510 	if (!ts->suspending && device_may_wakeup(&client->dev))
511 		pm_stay_awake(&client->dev);
512 
513 	/*
514 	 * Run at least once and exit the loop if
515 	 * - the optional interrupt GPIO isn't specified
516 	 *   (there is only one packet read per ISR invocation, then)
517 	 * or
518 	 * - the GPIO isn't active any more
519 	 *   (packet read until the level GPIO indicates that there is
520 	 *    no IRQ any more)
521 	 */
522 	do {
523 		ret = zforce_read_packet(ts, payload_buffer);
524 		if (ret < 0) {
525 			dev_err(&client->dev,
526 				"could not read packet, ret: %d\n", ret);
527 			break;
528 		}
529 
530 		payload =  &payload_buffer[PAYLOAD_BODY];
531 
532 		switch (payload[RESPONSE_ID]) {
533 		case NOTIFICATION_TOUCH:
534 			/*
535 			 * Always report touch-events received while
536 			 * suspending, when being a wakeup source
537 			 */
538 			if (ts->suspending && device_may_wakeup(&client->dev))
539 				pm_wakeup_event(&client->dev, 500);
540 			zforce_touch_event(ts, &payload[RESPONSE_DATA]);
541 			break;
542 
543 		case NOTIFICATION_BOOTCOMPLETE:
544 			ts->boot_complete = payload[RESPONSE_DATA];
545 			zforce_complete(ts, payload[RESPONSE_ID], 0);
546 			break;
547 
548 		case RESPONSE_INITIALIZE:
549 		case RESPONSE_DEACTIVATE:
550 		case RESPONSE_SETCONFIG:
551 		case RESPONSE_RESOLUTION:
552 		case RESPONSE_SCANFREQ:
553 			zforce_complete(ts, payload[RESPONSE_ID],
554 					payload[RESPONSE_DATA]);
555 			break;
556 
557 		case RESPONSE_STATUS:
558 			/*
559 			 * Version Payload Results
560 			 * [2:major] [2:minor] [2:build] [2:rev]
561 			 */
562 			ts->version_major = (payload[RESPONSE_DATA + 1] << 8) |
563 						payload[RESPONSE_DATA];
564 			ts->version_minor = (payload[RESPONSE_DATA + 3] << 8) |
565 						payload[RESPONSE_DATA + 2];
566 			ts->version_build = (payload[RESPONSE_DATA + 5] << 8) |
567 						payload[RESPONSE_DATA + 4];
568 			ts->version_rev   = (payload[RESPONSE_DATA + 7] << 8) |
569 						payload[RESPONSE_DATA + 6];
570 			dev_dbg(&ts->client->dev,
571 				"Firmware Version %04x:%04x %04x:%04x\n",
572 				ts->version_major, ts->version_minor,
573 				ts->version_build, ts->version_rev);
574 
575 			zforce_complete(ts, payload[RESPONSE_ID], 0);
576 			break;
577 
578 		case NOTIFICATION_INVALID_COMMAND:
579 			dev_err(&ts->client->dev, "invalid command: 0x%x\n",
580 				payload[RESPONSE_DATA]);
581 			break;
582 
583 		default:
584 			dev_err(&ts->client->dev,
585 				"unrecognized response id: 0x%x\n",
586 				payload[RESPONSE_ID]);
587 			break;
588 		}
589 	} while (gpiod_get_value_cansleep(ts->gpio_int));
590 
591 	if (!ts->suspending && device_may_wakeup(&client->dev))
592 		pm_relax(&client->dev);
593 
594 	dev_dbg(&client->dev, "finished interrupt\n");
595 
596 	return IRQ_HANDLED;
597 }
598 
599 static int zforce_input_open(struct input_dev *dev)
600 {
601 	struct zforce_ts *ts = input_get_drvdata(dev);
602 
603 	return zforce_start(ts);
604 }
605 
606 static void zforce_input_close(struct input_dev *dev)
607 {
608 	struct zforce_ts *ts = input_get_drvdata(dev);
609 	struct i2c_client *client = ts->client;
610 	int ret;
611 
612 	ret = zforce_stop(ts);
613 	if (ret)
614 		dev_warn(&client->dev, "stopping zforce failed\n");
615 
616 	return;
617 }
618 
619 static int __maybe_unused zforce_suspend(struct device *dev)
620 {
621 	struct i2c_client *client = to_i2c_client(dev);
622 	struct zforce_ts *ts = i2c_get_clientdata(client);
623 	struct input_dev *input = ts->input;
624 	int ret = 0;
625 
626 	mutex_lock(&input->mutex);
627 	ts->suspending = true;
628 
629 	/*
630 	 * When configured as a wakeup source device should always wake
631 	 * the system, therefore start device if necessary.
632 	 */
633 	if (device_may_wakeup(&client->dev)) {
634 		dev_dbg(&client->dev, "suspend while being a wakeup source\n");
635 
636 		/* Need to start device, if not open, to be a wakeup source. */
637 		if (!input->users) {
638 			ret = zforce_start(ts);
639 			if (ret)
640 				goto unlock;
641 		}
642 
643 		enable_irq_wake(client->irq);
644 	} else if (input->users) {
645 		dev_dbg(&client->dev,
646 			"suspend without being a wakeup source\n");
647 
648 		ret = zforce_stop(ts);
649 		if (ret)
650 			goto unlock;
651 
652 		disable_irq(client->irq);
653 	}
654 
655 	ts->suspended = true;
656 
657 unlock:
658 	ts->suspending = false;
659 	mutex_unlock(&input->mutex);
660 
661 	return ret;
662 }
663 
664 static int __maybe_unused zforce_resume(struct device *dev)
665 {
666 	struct i2c_client *client = to_i2c_client(dev);
667 	struct zforce_ts *ts = i2c_get_clientdata(client);
668 	struct input_dev *input = ts->input;
669 	int ret = 0;
670 
671 	mutex_lock(&input->mutex);
672 
673 	ts->suspended = false;
674 
675 	if (device_may_wakeup(&client->dev)) {
676 		dev_dbg(&client->dev, "resume from being a wakeup source\n");
677 
678 		disable_irq_wake(client->irq);
679 
680 		/* need to stop device if it was not open on suspend */
681 		if (!input->users) {
682 			ret = zforce_stop(ts);
683 			if (ret)
684 				goto unlock;
685 		}
686 	} else if (input->users) {
687 		dev_dbg(&client->dev, "resume without being a wakeup source\n");
688 
689 		enable_irq(client->irq);
690 
691 		ret = zforce_start(ts);
692 		if (ret < 0)
693 			goto unlock;
694 	}
695 
696 unlock:
697 	mutex_unlock(&input->mutex);
698 
699 	return ret;
700 }
701 
702 static SIMPLE_DEV_PM_OPS(zforce_pm_ops, zforce_suspend, zforce_resume);
703 
704 static void zforce_reset(void *data)
705 {
706 	struct zforce_ts *ts = data;
707 
708 	zforce_reset_assert(ts);
709 
710 	udelay(10);
711 
712 	if (!IS_ERR(ts->reg_vdd))
713 		regulator_disable(ts->reg_vdd);
714 }
715 
716 static struct zforce_ts_platdata *zforce_parse_dt(struct device *dev)
717 {
718 	struct zforce_ts_platdata *pdata;
719 	struct device_node *np = dev->of_node;
720 
721 	if (!np)
722 		return ERR_PTR(-ENOENT);
723 
724 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
725 	if (!pdata) {
726 		dev_err(dev, "failed to allocate platform data\n");
727 		return ERR_PTR(-ENOMEM);
728 	}
729 
730 	if (of_property_read_u32(np, "x-size", &pdata->x_max)) {
731 		dev_err(dev, "failed to get x-size property\n");
732 		return ERR_PTR(-EINVAL);
733 	}
734 
735 	if (of_property_read_u32(np, "y-size", &pdata->y_max)) {
736 		dev_err(dev, "failed to get y-size property\n");
737 		return ERR_PTR(-EINVAL);
738 	}
739 
740 	return pdata;
741 }
742 
743 static int zforce_probe(struct i2c_client *client,
744 			const struct i2c_device_id *id)
745 {
746 	const struct zforce_ts_platdata *pdata = dev_get_platdata(&client->dev);
747 	struct zforce_ts *ts;
748 	struct input_dev *input_dev;
749 	int ret;
750 
751 	if (!pdata) {
752 		pdata = zforce_parse_dt(&client->dev);
753 		if (IS_ERR(pdata))
754 			return PTR_ERR(pdata);
755 	}
756 
757 	ts = devm_kzalloc(&client->dev, sizeof(struct zforce_ts), GFP_KERNEL);
758 	if (!ts)
759 		return -ENOMEM;
760 
761 	ts->gpio_rst = devm_gpiod_get_optional(&client->dev, "reset",
762 					       GPIOD_OUT_HIGH);
763 	if (IS_ERR(ts->gpio_rst)) {
764 		ret = PTR_ERR(ts->gpio_rst);
765 		dev_err(&client->dev,
766 			"failed to request reset GPIO: %d\n", ret);
767 		return ret;
768 	}
769 
770 	if (ts->gpio_rst) {
771 		ts->gpio_int = devm_gpiod_get_optional(&client->dev, "irq",
772 						       GPIOD_IN);
773 		if (IS_ERR(ts->gpio_int)) {
774 			ret = PTR_ERR(ts->gpio_int);
775 			dev_err(&client->dev,
776 				"failed to request interrupt GPIO: %d\n", ret);
777 			return ret;
778 		}
779 	} else {
780 		/*
781 		 * Deprecated GPIO handling for compatibility
782 		 * with legacy binding.
783 		 */
784 
785 		/* INT GPIO */
786 		ts->gpio_int = devm_gpiod_get_index(&client->dev, NULL, 0,
787 						    GPIOD_IN);
788 		if (IS_ERR(ts->gpio_int)) {
789 			ret = PTR_ERR(ts->gpio_int);
790 			dev_err(&client->dev,
791 				"failed to request interrupt GPIO: %d\n", ret);
792 			return ret;
793 		}
794 
795 		/* RST GPIO */
796 		ts->gpio_rst = devm_gpiod_get_index(&client->dev, NULL, 1,
797 					    GPIOD_OUT_HIGH);
798 		if (IS_ERR(ts->gpio_rst)) {
799 			ret = PTR_ERR(ts->gpio_rst);
800 			dev_err(&client->dev,
801 				"failed to request reset GPIO: %d\n", ret);
802 			return ret;
803 		}
804 	}
805 
806 	ts->reg_vdd = devm_regulator_get_optional(&client->dev, "vdd");
807 	if (IS_ERR(ts->reg_vdd)) {
808 		ret = PTR_ERR(ts->reg_vdd);
809 		if (ret == -EPROBE_DEFER)
810 			return ret;
811 	} else {
812 		ret = regulator_enable(ts->reg_vdd);
813 		if (ret)
814 			return ret;
815 
816 		/*
817 		 * according to datasheet add 100us grace time after regular
818 		 * regulator enable delay.
819 		 */
820 		udelay(100);
821 	}
822 
823 	ret = devm_add_action(&client->dev, zforce_reset, ts);
824 	if (ret) {
825 		dev_err(&client->dev, "failed to register reset action, %d\n",
826 			ret);
827 
828 		/* hereafter the regulator will be disabled by the action */
829 		if (!IS_ERR(ts->reg_vdd))
830 			regulator_disable(ts->reg_vdd);
831 
832 		return ret;
833 	}
834 
835 	snprintf(ts->phys, sizeof(ts->phys),
836 		 "%s/input0", dev_name(&client->dev));
837 
838 	input_dev = devm_input_allocate_device(&client->dev);
839 	if (!input_dev) {
840 		dev_err(&client->dev, "could not allocate input device\n");
841 		return -ENOMEM;
842 	}
843 
844 	mutex_init(&ts->access_mutex);
845 	mutex_init(&ts->command_mutex);
846 
847 	ts->pdata = pdata;
848 	ts->client = client;
849 	ts->input = input_dev;
850 
851 	input_dev->name = "Neonode zForce touchscreen";
852 	input_dev->phys = ts->phys;
853 	input_dev->id.bustype = BUS_I2C;
854 
855 	input_dev->open = zforce_input_open;
856 	input_dev->close = zforce_input_close;
857 
858 	__set_bit(EV_KEY, input_dev->evbit);
859 	__set_bit(EV_SYN, input_dev->evbit);
860 	__set_bit(EV_ABS, input_dev->evbit);
861 
862 	/* For multi touch */
863 	input_set_abs_params(input_dev, ABS_MT_POSITION_X, 0,
864 			     pdata->x_max, 0, 0);
865 	input_set_abs_params(input_dev, ABS_MT_POSITION_Y, 0,
866 			     pdata->y_max, 0, 0);
867 
868 	input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0,
869 			     ZFORCE_MAX_AREA, 0, 0);
870 	input_set_abs_params(input_dev, ABS_MT_TOUCH_MINOR, 0,
871 			     ZFORCE_MAX_AREA, 0, 0);
872 	input_set_abs_params(input_dev, ABS_MT_ORIENTATION, 0, 1, 0, 0);
873 	input_mt_init_slots(input_dev, ZFORCE_REPORT_POINTS, INPUT_MT_DIRECT);
874 
875 	input_set_drvdata(ts->input, ts);
876 
877 	init_completion(&ts->command_done);
878 
879 	/*
880 	 * The zforce pulls the interrupt low when it has data ready.
881 	 * After it is triggered the isr thread runs until all the available
882 	 * packets have been read and the interrupt is high again.
883 	 * Therefore we can trigger the interrupt anytime it is low and do
884 	 * not need to limit it to the interrupt edge.
885 	 */
886 	ret = devm_request_threaded_irq(&client->dev, client->irq,
887 					zforce_irq, zforce_irq_thread,
888 					IRQF_TRIGGER_LOW | IRQF_ONESHOT,
889 					input_dev->name, ts);
890 	if (ret) {
891 		dev_err(&client->dev, "irq %d request failed\n", client->irq);
892 		return ret;
893 	}
894 
895 	i2c_set_clientdata(client, ts);
896 
897 	/* let the controller boot */
898 	zforce_reset_deassert(ts);
899 
900 	ts->command_waiting = NOTIFICATION_BOOTCOMPLETE;
901 	if (wait_for_completion_timeout(&ts->command_done, WAIT_TIMEOUT) == 0)
902 		dev_warn(&client->dev, "bootcomplete timed out\n");
903 
904 	/* need to start device to get version information */
905 	ret = zforce_command_wait(ts, COMMAND_INITIALIZE);
906 	if (ret) {
907 		dev_err(&client->dev, "unable to initialize, %d\n", ret);
908 		return ret;
909 	}
910 
911 	/* this gets the firmware version among other information */
912 	ret = zforce_command_wait(ts, COMMAND_STATUS);
913 	if (ret < 0) {
914 		dev_err(&client->dev, "couldn't get status, %d\n", ret);
915 		zforce_stop(ts);
916 		return ret;
917 	}
918 
919 	/* stop device and put it into sleep until it is opened */
920 	ret = zforce_stop(ts);
921 	if (ret < 0)
922 		return ret;
923 
924 	device_set_wakeup_capable(&client->dev, true);
925 
926 	ret = input_register_device(input_dev);
927 	if (ret) {
928 		dev_err(&client->dev, "could not register input device, %d\n",
929 			ret);
930 		return ret;
931 	}
932 
933 	return 0;
934 }
935 
936 static struct i2c_device_id zforce_idtable[] = {
937 	{ "zforce-ts", 0 },
938 	{ }
939 };
940 MODULE_DEVICE_TABLE(i2c, zforce_idtable);
941 
942 #ifdef CONFIG_OF
943 static const struct of_device_id zforce_dt_idtable[] = {
944 	{ .compatible = "neonode,zforce" },
945 	{},
946 };
947 MODULE_DEVICE_TABLE(of, zforce_dt_idtable);
948 #endif
949 
950 static struct i2c_driver zforce_driver = {
951 	.driver = {
952 		.name	= "zforce-ts",
953 		.pm	= &zforce_pm_ops,
954 		.of_match_table	= of_match_ptr(zforce_dt_idtable),
955 	},
956 	.probe		= zforce_probe,
957 	.id_table	= zforce_idtable,
958 };
959 
960 module_i2c_driver(zforce_driver);
961 
962 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
963 MODULE_DESCRIPTION("zForce TouchScreen Driver");
964 MODULE_LICENSE("GPL");
965