1 /*
2  * Elan Microelectronics touch panels with I2C interface
3  *
4  * Copyright (C) 2014 Elan Microelectronics Corporation.
5  * Scott Liu <scott.liu@emc.com.tw>
6  *
7  * This code is partly based on hid-multitouch.c:
8  *
9  *  Copyright (c) 2010-2012 Stephane Chatty <chatty@enac.fr>
10  *  Copyright (c) 2010-2012 Benjamin Tissoires <benjamin.tissoires@gmail.com>
11  *  Copyright (c) 2010-2012 Ecole Nationale de l'Aviation Civile, France
12  *
13  *
14  * This code is partly based on i2c-hid.c:
15  *
16  * Copyright (c) 2012 Benjamin Tissoires <benjamin.tissoires@gmail.com>
17  * Copyright (c) 2012 Ecole Nationale de l'Aviation Civile, France
18  * Copyright (c) 2012 Red Hat, Inc
19  */
20 
21 /*
22  * This software is licensed under the terms of the GNU General Public
23  * License version 2, as published by the Free Software Foundation, and
24  * may be copied, distributed, and modified under those terms.
25  */
26 
27 #include <linux/module.h>
28 #include <linux/input.h>
29 #include <linux/interrupt.h>
30 #include <linux/irq.h>
31 #include <linux/platform_device.h>
32 #include <linux/async.h>
33 #include <linux/i2c.h>
34 #include <linux/delay.h>
35 #include <linux/uaccess.h>
36 #include <linux/buffer_head.h>
37 #include <linux/slab.h>
38 #include <linux/firmware.h>
39 #include <linux/input/mt.h>
40 #include <linux/acpi.h>
41 #include <linux/of.h>
42 #include <linux/gpio/consumer.h>
43 #include <linux/regulator/consumer.h>
44 #include <asm/unaligned.h>
45 
46 /* Device, Driver information */
47 #define DEVICE_NAME	"elants_i2c"
48 
49 /* Convert from rows or columns into resolution */
50 #define ELAN_TS_RESOLUTION(n, m)   (((n) - 1) * (m))
51 
52 /* FW header data */
53 #define HEADER_SIZE		4
54 #define FW_HDR_TYPE		0
55 #define FW_HDR_COUNT		1
56 #define FW_HDR_LENGTH		2
57 
58 /* Buffer mode Queue Header information */
59 #define QUEUE_HEADER_SINGLE	0x62
60 #define QUEUE_HEADER_NORMAL	0X63
61 #define QUEUE_HEADER_WAIT	0x64
62 
63 /* Command header definition */
64 #define CMD_HEADER_WRITE	0x54
65 #define CMD_HEADER_READ		0x53
66 #define CMD_HEADER_6B_READ	0x5B
67 #define CMD_HEADER_RESP		0x52
68 #define CMD_HEADER_6B_RESP	0x9B
69 #define CMD_HEADER_HELLO	0x55
70 #define CMD_HEADER_REK		0x66
71 
72 /* FW position data */
73 #define PACKET_SIZE		55
74 #define MAX_CONTACT_NUM		10
75 #define FW_POS_HEADER		0
76 #define FW_POS_STATE		1
77 #define FW_POS_TOTAL		2
78 #define FW_POS_XY		3
79 #define FW_POS_CHECKSUM		34
80 #define FW_POS_WIDTH		35
81 #define FW_POS_PRESSURE		45
82 
83 #define HEADER_REPORT_10_FINGER	0x62
84 
85 /* Header (4 bytes) plus 3 fill 10-finger packets */
86 #define MAX_PACKET_SIZE		169
87 
88 #define BOOT_TIME_DELAY_MS	50
89 
90 /* FW read command, 0x53 0x?? 0x0, 0x01 */
91 #define E_ELAN_INFO_FW_VER	0x00
92 #define E_ELAN_INFO_BC_VER	0x10
93 #define E_ELAN_INFO_TEST_VER	0xE0
94 #define E_ELAN_INFO_FW_ID	0xF0
95 #define E_INFO_OSR		0xD6
96 #define E_INFO_PHY_SCAN		0xD7
97 #define E_INFO_PHY_DRIVER	0xD8
98 
99 #define MAX_RETRIES		3
100 #define MAX_FW_UPDATE_RETRIES	30
101 
102 #define ELAN_FW_PAGESIZE	132
103 
104 /* calibration timeout definition */
105 #define ELAN_CALI_TIMEOUT_MSEC	12000
106 
107 #define ELAN_POWERON_DELAY_USEC	500
108 #define ELAN_RESET_DELAY_MSEC	20
109 
110 enum elants_state {
111 	ELAN_STATE_NORMAL,
112 	ELAN_WAIT_QUEUE_HEADER,
113 	ELAN_WAIT_RECALIBRATION,
114 };
115 
116 enum elants_iap_mode {
117 	ELAN_IAP_OPERATIONAL,
118 	ELAN_IAP_RECOVERY,
119 };
120 
121 /* struct elants_data - represents state of Elan touchscreen device */
122 struct elants_data {
123 	struct i2c_client *client;
124 	struct input_dev *input;
125 
126 	struct regulator *vcc33;
127 	struct regulator *vccio;
128 	struct gpio_desc *reset_gpio;
129 
130 	u16 fw_version;
131 	u8 test_version;
132 	u8 solution_version;
133 	u8 bc_version;
134 	u8 iap_version;
135 	u16 hw_version;
136 	unsigned int x_res;	/* resolution in units/mm */
137 	unsigned int y_res;
138 	unsigned int x_max;
139 	unsigned int y_max;
140 
141 	enum elants_state state;
142 	enum elants_iap_mode iap_mode;
143 
144 	/* Guards against concurrent access to the device via sysfs */
145 	struct mutex sysfs_mutex;
146 
147 	u8 cmd_resp[HEADER_SIZE];
148 	struct completion cmd_done;
149 
150 	u8 buf[MAX_PACKET_SIZE];
151 
152 	bool wake_irq_enabled;
153 	bool keep_power_in_suspend;
154 };
155 
156 static int elants_i2c_send(struct i2c_client *client,
157 			   const void *data, size_t size)
158 {
159 	int ret;
160 
161 	ret = i2c_master_send(client, data, size);
162 	if (ret == size)
163 		return 0;
164 
165 	if (ret >= 0)
166 		ret = -EIO;
167 
168 	dev_err(&client->dev, "%s failed (%*ph): %d\n",
169 		__func__, (int)size, data, ret);
170 
171 	return ret;
172 }
173 
174 static int elants_i2c_read(struct i2c_client *client, void *data, size_t size)
175 {
176 	int ret;
177 
178 	ret = i2c_master_recv(client, data, size);
179 	if (ret == size)
180 		return 0;
181 
182 	if (ret >= 0)
183 		ret = -EIO;
184 
185 	dev_err(&client->dev, "%s failed: %d\n", __func__, ret);
186 
187 	return ret;
188 }
189 
190 static int elants_i2c_execute_command(struct i2c_client *client,
191 				      const u8 *cmd, size_t cmd_size,
192 				      u8 *resp, size_t resp_size)
193 {
194 	struct i2c_msg msgs[2];
195 	int ret;
196 	u8 expected_response;
197 
198 	switch (cmd[0]) {
199 	case CMD_HEADER_READ:
200 		expected_response = CMD_HEADER_RESP;
201 		break;
202 
203 	case CMD_HEADER_6B_READ:
204 		expected_response = CMD_HEADER_6B_RESP;
205 		break;
206 
207 	default:
208 		dev_err(&client->dev, "%s: invalid command %*ph\n",
209 			__func__, (int)cmd_size, cmd);
210 		return -EINVAL;
211 	}
212 
213 	msgs[0].addr = client->addr;
214 	msgs[0].flags = client->flags & I2C_M_TEN;
215 	msgs[0].len = cmd_size;
216 	msgs[0].buf = (u8 *)cmd;
217 
218 	msgs[1].addr = client->addr;
219 	msgs[1].flags = client->flags & I2C_M_TEN;
220 	msgs[1].flags |= I2C_M_RD;
221 	msgs[1].len = resp_size;
222 	msgs[1].buf = resp;
223 
224 	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
225 	if (ret < 0)
226 		return ret;
227 
228 	if (ret != ARRAY_SIZE(msgs) || resp[FW_HDR_TYPE] != expected_response)
229 		return -EIO;
230 
231 	return 0;
232 }
233 
234 static int elants_i2c_calibrate(struct elants_data *ts)
235 {
236 	struct i2c_client *client = ts->client;
237 	int ret, error;
238 	static const u8 w_flashkey[] = { 0x54, 0xC0, 0xE1, 0x5A };
239 	static const u8 rek[] = { 0x54, 0x29, 0x00, 0x01 };
240 	static const u8 rek_resp[] = { CMD_HEADER_REK, 0x66, 0x66, 0x66 };
241 
242 	disable_irq(client->irq);
243 
244 	ts->state = ELAN_WAIT_RECALIBRATION;
245 	reinit_completion(&ts->cmd_done);
246 
247 	elants_i2c_send(client, w_flashkey, sizeof(w_flashkey));
248 	elants_i2c_send(client, rek, sizeof(rek));
249 
250 	enable_irq(client->irq);
251 
252 	ret = wait_for_completion_interruptible_timeout(&ts->cmd_done,
253 				msecs_to_jiffies(ELAN_CALI_TIMEOUT_MSEC));
254 
255 	ts->state = ELAN_STATE_NORMAL;
256 
257 	if (ret <= 0) {
258 		error = ret < 0 ? ret : -ETIMEDOUT;
259 		dev_err(&client->dev,
260 			"error while waiting for calibration to complete: %d\n",
261 			error);
262 		return error;
263 	}
264 
265 	if (memcmp(rek_resp, ts->cmd_resp, sizeof(rek_resp))) {
266 		dev_err(&client->dev,
267 			"unexpected calibration response: %*ph\n",
268 			(int)sizeof(ts->cmd_resp), ts->cmd_resp);
269 		return -EINVAL;
270 	}
271 
272 	return 0;
273 }
274 
275 static int elants_i2c_sw_reset(struct i2c_client *client)
276 {
277 	const u8 soft_rst_cmd[] = { 0x77, 0x77, 0x77, 0x77 };
278 	int error;
279 
280 	error = elants_i2c_send(client, soft_rst_cmd,
281 				sizeof(soft_rst_cmd));
282 	if (error) {
283 		dev_err(&client->dev, "software reset failed: %d\n", error);
284 		return error;
285 	}
286 
287 	/*
288 	 * We should wait at least 10 msec (but no more than 40) before
289 	 * sending fastboot or IAP command to the device.
290 	 */
291 	msleep(30);
292 
293 	return 0;
294 }
295 
296 static u16 elants_i2c_parse_version(u8 *buf)
297 {
298 	return get_unaligned_be32(buf) >> 4;
299 }
300 
301 static int elants_i2c_query_hw_version(struct elants_data *ts)
302 {
303 	struct i2c_client *client = ts->client;
304 	int error, retry_cnt;
305 	const u8 cmd[] = { CMD_HEADER_READ, E_ELAN_INFO_FW_ID, 0x00, 0x01 };
306 	u8 resp[HEADER_SIZE];
307 
308 	for (retry_cnt = 0; retry_cnt < MAX_RETRIES; retry_cnt++) {
309 		error = elants_i2c_execute_command(client, cmd, sizeof(cmd),
310 						   resp, sizeof(resp));
311 		if (!error) {
312 			ts->hw_version = elants_i2c_parse_version(resp);
313 			if (ts->hw_version != 0xffff)
314 				return 0;
315 		}
316 
317 		dev_dbg(&client->dev, "read fw id error=%d, buf=%*phC\n",
318 			error, (int)sizeof(resp), resp);
319 	}
320 
321 	if (error) {
322 		dev_err(&client->dev,
323 			"Failed to read fw id: %d\n", error);
324 		return error;
325 	}
326 
327 	dev_err(&client->dev, "Invalid fw id: %#04x\n", ts->hw_version);
328 
329 	return -EINVAL;
330 }
331 
332 static int elants_i2c_query_fw_version(struct elants_data *ts)
333 {
334 	struct i2c_client *client = ts->client;
335 	int error, retry_cnt;
336 	const u8 cmd[] = { CMD_HEADER_READ, E_ELAN_INFO_FW_VER, 0x00, 0x01 };
337 	u8 resp[HEADER_SIZE];
338 
339 	for (retry_cnt = 0; retry_cnt < MAX_RETRIES; retry_cnt++) {
340 		error = elants_i2c_execute_command(client, cmd, sizeof(cmd),
341 						   resp, sizeof(resp));
342 		if (!error) {
343 			ts->fw_version = elants_i2c_parse_version(resp);
344 			if (ts->fw_version != 0x0000 &&
345 			    ts->fw_version != 0xffff)
346 				return 0;
347 		}
348 
349 		dev_dbg(&client->dev, "read fw version error=%d, buf=%*phC\n",
350 			error, (int)sizeof(resp), resp);
351 	}
352 
353 	dev_err(&client->dev,
354 		"Failed to read fw version or fw version is invalid\n");
355 
356 	return -EINVAL;
357 }
358 
359 static int elants_i2c_query_test_version(struct elants_data *ts)
360 {
361 	struct i2c_client *client = ts->client;
362 	int error, retry_cnt;
363 	u16 version;
364 	const u8 cmd[] = { CMD_HEADER_READ, E_ELAN_INFO_TEST_VER, 0x00, 0x01 };
365 	u8 resp[HEADER_SIZE];
366 
367 	for (retry_cnt = 0; retry_cnt < MAX_RETRIES; retry_cnt++) {
368 		error = elants_i2c_execute_command(client, cmd, sizeof(cmd),
369 						   resp, sizeof(resp));
370 		if (!error) {
371 			version = elants_i2c_parse_version(resp);
372 			ts->test_version = version >> 8;
373 			ts->solution_version = version & 0xff;
374 
375 			return 0;
376 		}
377 
378 		dev_dbg(&client->dev,
379 			"read test version error rc=%d, buf=%*phC\n",
380 			error, (int)sizeof(resp), resp);
381 	}
382 
383 	dev_err(&client->dev, "Failed to read test version\n");
384 
385 	return -EINVAL;
386 }
387 
388 static int elants_i2c_query_bc_version(struct elants_data *ts)
389 {
390 	struct i2c_client *client = ts->client;
391 	const u8 cmd[] = { CMD_HEADER_READ, E_ELAN_INFO_BC_VER, 0x00, 0x01 };
392 	u8 resp[HEADER_SIZE];
393 	u16 version;
394 	int error;
395 
396 	error = elants_i2c_execute_command(client, cmd, sizeof(cmd),
397 					   resp, sizeof(resp));
398 	if (error) {
399 		dev_err(&client->dev,
400 			"read BC version error=%d, buf=%*phC\n",
401 			error, (int)sizeof(resp), resp);
402 		return error;
403 	}
404 
405 	version = elants_i2c_parse_version(resp);
406 	ts->bc_version = version >> 8;
407 	ts->iap_version = version & 0xff;
408 
409 	return 0;
410 }
411 
412 static int elants_i2c_query_ts_info(struct elants_data *ts)
413 {
414 	struct i2c_client *client = ts->client;
415 	int error;
416 	u8 resp[17];
417 	u16 phy_x, phy_y, rows, cols, osr;
418 	const u8 get_resolution_cmd[] = {
419 		CMD_HEADER_6B_READ, 0x00, 0x00, 0x00, 0x00, 0x00
420 	};
421 	const u8 get_osr_cmd[] = {
422 		CMD_HEADER_READ, E_INFO_OSR, 0x00, 0x01
423 	};
424 	const u8 get_physical_scan_cmd[] = {
425 		CMD_HEADER_READ, E_INFO_PHY_SCAN, 0x00, 0x01
426 	};
427 	const u8 get_physical_drive_cmd[] = {
428 		CMD_HEADER_READ, E_INFO_PHY_DRIVER, 0x00, 0x01
429 	};
430 
431 	/* Get trace number */
432 	error = elants_i2c_execute_command(client,
433 					   get_resolution_cmd,
434 					   sizeof(get_resolution_cmd),
435 					   resp, sizeof(resp));
436 	if (error) {
437 		dev_err(&client->dev, "get resolution command failed: %d\n",
438 			error);
439 		return error;
440 	}
441 
442 	rows = resp[2] + resp[6] + resp[10];
443 	cols = resp[3] + resp[7] + resp[11];
444 
445 	/* Process mm_to_pixel information */
446 	error = elants_i2c_execute_command(client,
447 					   get_osr_cmd, sizeof(get_osr_cmd),
448 					   resp, sizeof(resp));
449 	if (error) {
450 		dev_err(&client->dev, "get osr command failed: %d\n",
451 			error);
452 		return error;
453 	}
454 
455 	osr = resp[3];
456 
457 	error = elants_i2c_execute_command(client,
458 					   get_physical_scan_cmd,
459 					   sizeof(get_physical_scan_cmd),
460 					   resp, sizeof(resp));
461 	if (error) {
462 		dev_err(&client->dev, "get physical scan command failed: %d\n",
463 			error);
464 		return error;
465 	}
466 
467 	phy_x = get_unaligned_be16(&resp[2]);
468 
469 	error = elants_i2c_execute_command(client,
470 					   get_physical_drive_cmd,
471 					   sizeof(get_physical_drive_cmd),
472 					   resp, sizeof(resp));
473 	if (error) {
474 		dev_err(&client->dev, "get physical drive command failed: %d\n",
475 			error);
476 		return error;
477 	}
478 
479 	phy_y = get_unaligned_be16(&resp[2]);
480 
481 	dev_dbg(&client->dev, "phy_x=%d, phy_y=%d\n", phy_x, phy_y);
482 
483 	if (rows == 0 || cols == 0 || osr == 0) {
484 		dev_warn(&client->dev,
485 			 "invalid trace number data: %d, %d, %d\n",
486 			 rows, cols, osr);
487 	} else {
488 		/* translate trace number to TS resolution */
489 		ts->x_max = ELAN_TS_RESOLUTION(rows, osr);
490 		ts->x_res = DIV_ROUND_CLOSEST(ts->x_max, phy_x);
491 		ts->y_max = ELAN_TS_RESOLUTION(cols, osr);
492 		ts->y_res = DIV_ROUND_CLOSEST(ts->y_max, phy_y);
493 	}
494 
495 	return 0;
496 }
497 
498 static int elants_i2c_fastboot(struct i2c_client *client)
499 {
500 	const u8 boot_cmd[] = { 0x4D, 0x61, 0x69, 0x6E };
501 	int error;
502 
503 	error = elants_i2c_send(client, boot_cmd, sizeof(boot_cmd));
504 	if (error) {
505 		dev_err(&client->dev, "boot failed: %d\n", error);
506 		return error;
507 	}
508 
509 	dev_dbg(&client->dev, "boot success -- 0x%x\n", client->addr);
510 	return 0;
511 }
512 
513 static int elants_i2c_initialize(struct elants_data *ts)
514 {
515 	struct i2c_client *client = ts->client;
516 	int error, error2, retry_cnt;
517 	const u8 hello_packet[] = { 0x55, 0x55, 0x55, 0x55 };
518 	const u8 recov_packet[] = { 0x55, 0x55, 0x80, 0x80 };
519 	u8 buf[HEADER_SIZE];
520 
521 	for (retry_cnt = 0; retry_cnt < MAX_RETRIES; retry_cnt++) {
522 		error = elants_i2c_sw_reset(client);
523 		if (error) {
524 			/* Continue initializing if it's the last try */
525 			if (retry_cnt < MAX_RETRIES - 1)
526 				continue;
527 		}
528 
529 		error = elants_i2c_fastboot(client);
530 		if (error) {
531 			/* Continue initializing if it's the last try */
532 			if (retry_cnt < MAX_RETRIES - 1)
533 				continue;
534 		}
535 
536 		/* Wait for Hello packet */
537 		msleep(BOOT_TIME_DELAY_MS);
538 
539 		error = elants_i2c_read(client, buf, sizeof(buf));
540 		if (error) {
541 			dev_err(&client->dev,
542 				"failed to read 'hello' packet: %d\n", error);
543 		} else if (!memcmp(buf, hello_packet, sizeof(hello_packet))) {
544 			ts->iap_mode = ELAN_IAP_OPERATIONAL;
545 			break;
546 		} else if (!memcmp(buf, recov_packet, sizeof(recov_packet))) {
547 			/*
548 			 * Setting error code will mark device
549 			 * in recovery mode below.
550 			 */
551 			error = -EIO;
552 			break;
553 		} else {
554 			error = -EINVAL;
555 			dev_err(&client->dev,
556 				"invalid 'hello' packet: %*ph\n",
557 				(int)sizeof(buf), buf);
558 		}
559 	}
560 
561 	/* hw version is available even if device in recovery state */
562 	error2 = elants_i2c_query_hw_version(ts);
563 	if (!error)
564 		error = error2;
565 
566 	if (!error)
567 		error = elants_i2c_query_fw_version(ts);
568 	if (!error)
569 		error = elants_i2c_query_test_version(ts);
570 	if (!error)
571 		error = elants_i2c_query_bc_version(ts);
572 	if (!error)
573 		error = elants_i2c_query_ts_info(ts);
574 
575 	if (error)
576 		ts->iap_mode = ELAN_IAP_RECOVERY;
577 
578 	return 0;
579 }
580 
581 /*
582  * Firmware update interface.
583  */
584 
585 static int elants_i2c_fw_write_page(struct i2c_client *client,
586 				    const void *page)
587 {
588 	const u8 ack_ok[] = { 0xaa, 0xaa };
589 	u8 buf[2];
590 	int retry;
591 	int error;
592 
593 	for (retry = 0; retry < MAX_FW_UPDATE_RETRIES; retry++) {
594 		error = elants_i2c_send(client, page, ELAN_FW_PAGESIZE);
595 		if (error) {
596 			dev_err(&client->dev,
597 				"IAP Write Page failed: %d\n", error);
598 			continue;
599 		}
600 
601 		error = elants_i2c_read(client, buf, 2);
602 		if (error) {
603 			dev_err(&client->dev,
604 				"IAP Ack read failed: %d\n", error);
605 			return error;
606 		}
607 
608 		if (!memcmp(buf, ack_ok, sizeof(ack_ok)))
609 			return 0;
610 
611 		error = -EIO;
612 		dev_err(&client->dev,
613 			"IAP Get Ack Error [%02x:%02x]\n",
614 			buf[0], buf[1]);
615 	}
616 
617 	return error;
618 }
619 
620 static int elants_i2c_do_update_firmware(struct i2c_client *client,
621 					 const struct firmware *fw,
622 					 bool force)
623 {
624 	const u8 enter_iap[] = { 0x45, 0x49, 0x41, 0x50 };
625 	const u8 enter_iap2[] = { 0x54, 0x00, 0x12, 0x34 };
626 	const u8 iap_ack[] = { 0x55, 0xaa, 0x33, 0xcc };
627 	const u8 close_idle[] = {0x54, 0x2c, 0x01, 0x01};
628 	u8 buf[HEADER_SIZE];
629 	u16 send_id;
630 	int page, n_fw_pages;
631 	int error;
632 
633 	/* Recovery mode detection! */
634 	if (force) {
635 		dev_dbg(&client->dev, "Recovery mode procedure\n");
636 		error = elants_i2c_send(client, enter_iap2, sizeof(enter_iap2));
637 	} else {
638 		/* Start IAP Procedure */
639 		dev_dbg(&client->dev, "Normal IAP procedure\n");
640 		/* Close idle mode */
641 		error = elants_i2c_send(client, close_idle, sizeof(close_idle));
642 		if (error)
643 			dev_err(&client->dev, "Failed close idle: %d\n", error);
644 		msleep(60);
645 		elants_i2c_sw_reset(client);
646 		msleep(20);
647 		error = elants_i2c_send(client, enter_iap, sizeof(enter_iap));
648 	}
649 
650 	if (error) {
651 		dev_err(&client->dev, "failed to enter IAP mode: %d\n", error);
652 		return error;
653 	}
654 
655 	msleep(20);
656 
657 	/* check IAP state */
658 	error = elants_i2c_read(client, buf, 4);
659 	if (error) {
660 		dev_err(&client->dev,
661 			"failed to read IAP acknowledgement: %d\n",
662 			error);
663 		return error;
664 	}
665 
666 	if (memcmp(buf, iap_ack, sizeof(iap_ack))) {
667 		dev_err(&client->dev,
668 			"failed to enter IAP: %*ph (expected %*ph)\n",
669 			(int)sizeof(buf), buf, (int)sizeof(iap_ack), iap_ack);
670 		return -EIO;
671 	}
672 
673 	dev_info(&client->dev, "successfully entered IAP mode");
674 
675 	send_id = client->addr;
676 	error = elants_i2c_send(client, &send_id, 1);
677 	if (error) {
678 		dev_err(&client->dev, "sending dummy byte failed: %d\n",
679 			error);
680 		return error;
681 	}
682 
683 	/* Clear the last page of Master */
684 	error = elants_i2c_send(client, fw->data, ELAN_FW_PAGESIZE);
685 	if (error) {
686 		dev_err(&client->dev, "clearing of the last page failed: %d\n",
687 			error);
688 		return error;
689 	}
690 
691 	error = elants_i2c_read(client, buf, 2);
692 	if (error) {
693 		dev_err(&client->dev,
694 			"failed to read ACK for clearing the last page: %d\n",
695 			error);
696 		return error;
697 	}
698 
699 	n_fw_pages = fw->size / ELAN_FW_PAGESIZE;
700 	dev_dbg(&client->dev, "IAP Pages = %d\n", n_fw_pages);
701 
702 	for (page = 0; page < n_fw_pages; page++) {
703 		error = elants_i2c_fw_write_page(client,
704 					fw->data + page * ELAN_FW_PAGESIZE);
705 		if (error) {
706 			dev_err(&client->dev,
707 				"failed to write FW page %d: %d\n",
708 				page, error);
709 			return error;
710 		}
711 	}
712 
713 	/* Old iap needs to wait 200ms for WDT and rest is for hello packets */
714 	msleep(300);
715 
716 	dev_info(&client->dev, "firmware update completed\n");
717 	return 0;
718 }
719 
720 static int elants_i2c_fw_update(struct elants_data *ts)
721 {
722 	struct i2c_client *client = ts->client;
723 	const struct firmware *fw;
724 	char *fw_name;
725 	int error;
726 
727 	fw_name = kasprintf(GFP_KERNEL, "elants_i2c_%04x.bin", ts->hw_version);
728 	if (!fw_name)
729 		return -ENOMEM;
730 
731 	dev_info(&client->dev, "requesting fw name = %s\n", fw_name);
732 	error = request_firmware(&fw, fw_name, &client->dev);
733 	kfree(fw_name);
734 	if (error) {
735 		dev_err(&client->dev, "failed to request firmware: %d\n",
736 			error);
737 		return error;
738 	}
739 
740 	if (fw->size % ELAN_FW_PAGESIZE) {
741 		dev_err(&client->dev, "invalid firmware length: %zu\n",
742 			fw->size);
743 		error = -EINVAL;
744 		goto out;
745 	}
746 
747 	disable_irq(client->irq);
748 
749 	error = elants_i2c_do_update_firmware(client, fw,
750 					ts->iap_mode == ELAN_IAP_RECOVERY);
751 	if (error) {
752 		dev_err(&client->dev, "firmware update failed: %d\n", error);
753 		ts->iap_mode = ELAN_IAP_RECOVERY;
754 		goto out_enable_irq;
755 	}
756 
757 	error = elants_i2c_initialize(ts);
758 	if (error) {
759 		dev_err(&client->dev,
760 			"failed to initialize device after firmware update: %d\n",
761 			error);
762 		ts->iap_mode = ELAN_IAP_RECOVERY;
763 		goto out_enable_irq;
764 	}
765 
766 	ts->iap_mode = ELAN_IAP_OPERATIONAL;
767 
768 out_enable_irq:
769 	ts->state = ELAN_STATE_NORMAL;
770 	enable_irq(client->irq);
771 	msleep(100);
772 
773 	if (!error)
774 		elants_i2c_calibrate(ts);
775 out:
776 	release_firmware(fw);
777 	return error;
778 }
779 
780 /*
781  * Event reporting.
782  */
783 
784 static void elants_i2c_mt_event(struct elants_data *ts, u8 *buf)
785 {
786 	struct input_dev *input = ts->input;
787 	unsigned int n_fingers;
788 	u16 finger_state;
789 	int i;
790 
791 	n_fingers = buf[FW_POS_STATE + 1] & 0x0f;
792 	finger_state = ((buf[FW_POS_STATE + 1] & 0x30) << 4) |
793 			buf[FW_POS_STATE];
794 
795 	dev_dbg(&ts->client->dev,
796 		"n_fingers: %u, state: %04x\n",  n_fingers, finger_state);
797 
798 	for (i = 0; i < MAX_CONTACT_NUM && n_fingers; i++) {
799 		if (finger_state & 1) {
800 			unsigned int x, y, p, w;
801 			u8 *pos;
802 
803 			pos = &buf[FW_POS_XY + i * 3];
804 			x = (((u16)pos[0] & 0xf0) << 4) | pos[1];
805 			y = (((u16)pos[0] & 0x0f) << 8) | pos[2];
806 			p = buf[FW_POS_PRESSURE + i];
807 			w = buf[FW_POS_WIDTH + i];
808 
809 			dev_dbg(&ts->client->dev, "i=%d x=%d y=%d p=%d w=%d\n",
810 				i, x, y, p, w);
811 
812 			input_mt_slot(input, i);
813 			input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
814 			input_event(input, EV_ABS, ABS_MT_POSITION_X, x);
815 			input_event(input, EV_ABS, ABS_MT_POSITION_Y, y);
816 			input_event(input, EV_ABS, ABS_MT_PRESSURE, p);
817 			input_event(input, EV_ABS, ABS_MT_TOUCH_MAJOR, w);
818 
819 			n_fingers--;
820 		}
821 
822 		finger_state >>= 1;
823 	}
824 
825 	input_mt_sync_frame(input);
826 	input_sync(input);
827 }
828 
829 static u8 elants_i2c_calculate_checksum(u8 *buf)
830 {
831 	u8 checksum = 0;
832 	u8 i;
833 
834 	for (i = 0; i < FW_POS_CHECKSUM; i++)
835 		checksum += buf[i];
836 
837 	return checksum;
838 }
839 
840 static void elants_i2c_event(struct elants_data *ts, u8 *buf)
841 {
842 	u8 checksum = elants_i2c_calculate_checksum(buf);
843 
844 	if (unlikely(buf[FW_POS_CHECKSUM] != checksum))
845 		dev_warn(&ts->client->dev,
846 			 "%s: invalid checksum for packet %02x: %02x vs. %02x\n",
847 			 __func__, buf[FW_POS_HEADER],
848 			 checksum, buf[FW_POS_CHECKSUM]);
849 	else if (unlikely(buf[FW_POS_HEADER] != HEADER_REPORT_10_FINGER))
850 		dev_warn(&ts->client->dev,
851 			 "%s: unknown packet type: %02x\n",
852 			 __func__, buf[FW_POS_HEADER]);
853 	else
854 		elants_i2c_mt_event(ts, buf);
855 }
856 
857 static irqreturn_t elants_i2c_irq(int irq, void *_dev)
858 {
859 	const u8 wait_packet[] = { 0x64, 0x64, 0x64, 0x64 };
860 	struct elants_data *ts = _dev;
861 	struct i2c_client *client = ts->client;
862 	int report_count, report_len;
863 	int i;
864 	int len;
865 
866 	len = i2c_master_recv(client, ts->buf, sizeof(ts->buf));
867 	if (len < 0) {
868 		dev_err(&client->dev, "%s: failed to read data: %d\n",
869 			__func__, len);
870 		goto out;
871 	}
872 
873 	dev_dbg(&client->dev, "%s: packet %*ph\n",
874 		__func__, HEADER_SIZE, ts->buf);
875 
876 	switch (ts->state) {
877 	case ELAN_WAIT_RECALIBRATION:
878 		if (ts->buf[FW_HDR_TYPE] == CMD_HEADER_REK) {
879 			memcpy(ts->cmd_resp, ts->buf, sizeof(ts->cmd_resp));
880 			complete(&ts->cmd_done);
881 			ts->state = ELAN_STATE_NORMAL;
882 		}
883 		break;
884 
885 	case ELAN_WAIT_QUEUE_HEADER:
886 		if (ts->buf[FW_HDR_TYPE] != QUEUE_HEADER_NORMAL)
887 			break;
888 
889 		ts->state = ELAN_STATE_NORMAL;
890 		/* fall through */
891 
892 	case ELAN_STATE_NORMAL:
893 
894 		switch (ts->buf[FW_HDR_TYPE]) {
895 		case CMD_HEADER_HELLO:
896 		case CMD_HEADER_RESP:
897 		case CMD_HEADER_REK:
898 			break;
899 
900 		case QUEUE_HEADER_WAIT:
901 			if (memcmp(ts->buf, wait_packet, sizeof(wait_packet))) {
902 				dev_err(&client->dev,
903 					"invalid wait packet %*ph\n",
904 					HEADER_SIZE, ts->buf);
905 			} else {
906 				ts->state = ELAN_WAIT_QUEUE_HEADER;
907 				udelay(30);
908 			}
909 			break;
910 
911 		case QUEUE_HEADER_SINGLE:
912 			elants_i2c_event(ts, &ts->buf[HEADER_SIZE]);
913 			break;
914 
915 		case QUEUE_HEADER_NORMAL:
916 			report_count = ts->buf[FW_HDR_COUNT];
917 			if (report_count == 0 || report_count > 3) {
918 				dev_err(&client->dev,
919 					"bad report count: %*ph\n",
920 					HEADER_SIZE, ts->buf);
921 				break;
922 			}
923 
924 			report_len = ts->buf[FW_HDR_LENGTH] / report_count;
925 			if (report_len != PACKET_SIZE) {
926 				dev_err(&client->dev,
927 					"mismatching report length: %*ph\n",
928 					HEADER_SIZE, ts->buf);
929 				break;
930 			}
931 
932 			for (i = 0; i < report_count; i++) {
933 				u8 *buf = ts->buf + HEADER_SIZE +
934 							i * PACKET_SIZE;
935 				elants_i2c_event(ts, buf);
936 			}
937 			break;
938 
939 		default:
940 			dev_err(&client->dev, "unknown packet %*ph\n",
941 				HEADER_SIZE, ts->buf);
942 			break;
943 		}
944 		break;
945 	}
946 
947 out:
948 	return IRQ_HANDLED;
949 }
950 
951 /*
952  * sysfs interface
953  */
954 static ssize_t calibrate_store(struct device *dev,
955 			       struct device_attribute *attr,
956 			      const char *buf, size_t count)
957 {
958 	struct i2c_client *client = to_i2c_client(dev);
959 	struct elants_data *ts = i2c_get_clientdata(client);
960 	int error;
961 
962 	error = mutex_lock_interruptible(&ts->sysfs_mutex);
963 	if (error)
964 		return error;
965 
966 	error = elants_i2c_calibrate(ts);
967 
968 	mutex_unlock(&ts->sysfs_mutex);
969 	return error ?: count;
970 }
971 
972 static ssize_t write_update_fw(struct device *dev,
973 			       struct device_attribute *attr,
974 			       const char *buf, size_t count)
975 {
976 	struct i2c_client *client = to_i2c_client(dev);
977 	struct elants_data *ts = i2c_get_clientdata(client);
978 	int error;
979 
980 	error = mutex_lock_interruptible(&ts->sysfs_mutex);
981 	if (error)
982 		return error;
983 
984 	error = elants_i2c_fw_update(ts);
985 	dev_dbg(dev, "firmware update result: %d\n", error);
986 
987 	mutex_unlock(&ts->sysfs_mutex);
988 	return error ?: count;
989 }
990 
991 static ssize_t show_iap_mode(struct device *dev,
992 			     struct device_attribute *attr, char *buf)
993 {
994 	struct i2c_client *client = to_i2c_client(dev);
995 	struct elants_data *ts = i2c_get_clientdata(client);
996 
997 	return sprintf(buf, "%s\n",
998 		       ts->iap_mode == ELAN_IAP_OPERATIONAL ?
999 				"Normal" : "Recovery");
1000 }
1001 
1002 static DEVICE_ATTR_WO(calibrate);
1003 static DEVICE_ATTR(iap_mode, S_IRUGO, show_iap_mode, NULL);
1004 static DEVICE_ATTR(update_fw, S_IWUSR, NULL, write_update_fw);
1005 
1006 struct elants_version_attribute {
1007 	struct device_attribute dattr;
1008 	size_t field_offset;
1009 	size_t field_size;
1010 };
1011 
1012 #define __ELANTS_FIELD_SIZE(_field)					\
1013 	sizeof(((struct elants_data *)NULL)->_field)
1014 #define __ELANTS_VERIFY_SIZE(_field)					\
1015 	(BUILD_BUG_ON_ZERO(__ELANTS_FIELD_SIZE(_field) > 2) +		\
1016 	 __ELANTS_FIELD_SIZE(_field))
1017 #define ELANTS_VERSION_ATTR(_field)					\
1018 	struct elants_version_attribute elants_ver_attr_##_field = {	\
1019 		.dattr = __ATTR(_field, S_IRUGO,			\
1020 				elants_version_attribute_show, NULL),	\
1021 		.field_offset = offsetof(struct elants_data, _field),	\
1022 		.field_size = __ELANTS_VERIFY_SIZE(_field),		\
1023 	}
1024 
1025 static ssize_t elants_version_attribute_show(struct device *dev,
1026 					     struct device_attribute *dattr,
1027 					     char *buf)
1028 {
1029 	struct i2c_client *client = to_i2c_client(dev);
1030 	struct elants_data *ts = i2c_get_clientdata(client);
1031 	struct elants_version_attribute *attr =
1032 		container_of(dattr, struct elants_version_attribute, dattr);
1033 	u8 *field = (u8 *)((char *)ts + attr->field_offset);
1034 	unsigned int fmt_size;
1035 	unsigned int val;
1036 
1037 	if (attr->field_size == 1) {
1038 		val = *field;
1039 		fmt_size = 2; /* 2 HEX digits */
1040 	} else {
1041 		val = *(u16 *)field;
1042 		fmt_size = 4; /* 4 HEX digits */
1043 	}
1044 
1045 	return sprintf(buf, "%0*x\n", fmt_size, val);
1046 }
1047 
1048 static ELANTS_VERSION_ATTR(fw_version);
1049 static ELANTS_VERSION_ATTR(hw_version);
1050 static ELANTS_VERSION_ATTR(test_version);
1051 static ELANTS_VERSION_ATTR(solution_version);
1052 static ELANTS_VERSION_ATTR(bc_version);
1053 static ELANTS_VERSION_ATTR(iap_version);
1054 
1055 static struct attribute *elants_attributes[] = {
1056 	&dev_attr_calibrate.attr,
1057 	&dev_attr_update_fw.attr,
1058 	&dev_attr_iap_mode.attr,
1059 
1060 	&elants_ver_attr_fw_version.dattr.attr,
1061 	&elants_ver_attr_hw_version.dattr.attr,
1062 	&elants_ver_attr_test_version.dattr.attr,
1063 	&elants_ver_attr_solution_version.dattr.attr,
1064 	&elants_ver_attr_bc_version.dattr.attr,
1065 	&elants_ver_attr_iap_version.dattr.attr,
1066 	NULL
1067 };
1068 
1069 static const struct attribute_group elants_attribute_group = {
1070 	.attrs = elants_attributes,
1071 };
1072 
1073 static int elants_i2c_power_on(struct elants_data *ts)
1074 {
1075 	int error;
1076 
1077 	/*
1078 	 * If we do not have reset gpio assume platform firmware
1079 	 * controls regulators and does power them on for us.
1080 	 */
1081 	if (IS_ERR_OR_NULL(ts->reset_gpio))
1082 		return 0;
1083 
1084 	gpiod_set_value_cansleep(ts->reset_gpio, 1);
1085 
1086 	error = regulator_enable(ts->vcc33);
1087 	if (error) {
1088 		dev_err(&ts->client->dev,
1089 			"failed to enable vcc33 regulator: %d\n",
1090 			error);
1091 		goto release_reset_gpio;
1092 	}
1093 
1094 	error = regulator_enable(ts->vccio);
1095 	if (error) {
1096 		dev_err(&ts->client->dev,
1097 			"failed to enable vccio regulator: %d\n",
1098 			error);
1099 		regulator_disable(ts->vcc33);
1100 		goto release_reset_gpio;
1101 	}
1102 
1103 	/*
1104 	 * We need to wait a bit after powering on controller before
1105 	 * we are allowed to release reset GPIO.
1106 	 */
1107 	udelay(ELAN_POWERON_DELAY_USEC);
1108 
1109 release_reset_gpio:
1110 	gpiod_set_value_cansleep(ts->reset_gpio, 0);
1111 	if (error)
1112 		return error;
1113 
1114 	msleep(ELAN_RESET_DELAY_MSEC);
1115 
1116 	return 0;
1117 }
1118 
1119 static void elants_i2c_power_off(void *_data)
1120 {
1121 	struct elants_data *ts = _data;
1122 
1123 	if (!IS_ERR_OR_NULL(ts->reset_gpio)) {
1124 		/*
1125 		 * Activate reset gpio to prevent leakage through the
1126 		 * pin once we shut off power to the controller.
1127 		 */
1128 		gpiod_set_value_cansleep(ts->reset_gpio, 1);
1129 		regulator_disable(ts->vccio);
1130 		regulator_disable(ts->vcc33);
1131 	}
1132 }
1133 
1134 static int elants_i2c_probe(struct i2c_client *client,
1135 			    const struct i2c_device_id *id)
1136 {
1137 	union i2c_smbus_data dummy;
1138 	struct elants_data *ts;
1139 	unsigned long irqflags;
1140 	int error;
1141 
1142 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
1143 		dev_err(&client->dev,
1144 			"%s: i2c check functionality error\n", DEVICE_NAME);
1145 		return -ENXIO;
1146 	}
1147 
1148 	ts = devm_kzalloc(&client->dev, sizeof(struct elants_data), GFP_KERNEL);
1149 	if (!ts)
1150 		return -ENOMEM;
1151 
1152 	mutex_init(&ts->sysfs_mutex);
1153 	init_completion(&ts->cmd_done);
1154 
1155 	ts->client = client;
1156 	i2c_set_clientdata(client, ts);
1157 
1158 	ts->vcc33 = devm_regulator_get(&client->dev, "vcc33");
1159 	if (IS_ERR(ts->vcc33)) {
1160 		error = PTR_ERR(ts->vcc33);
1161 		if (error != -EPROBE_DEFER)
1162 			dev_err(&client->dev,
1163 				"Failed to get 'vcc33' regulator: %d\n",
1164 				error);
1165 		return error;
1166 	}
1167 
1168 	ts->vccio = devm_regulator_get(&client->dev, "vccio");
1169 	if (IS_ERR(ts->vccio)) {
1170 		error = PTR_ERR(ts->vccio);
1171 		if (error != -EPROBE_DEFER)
1172 			dev_err(&client->dev,
1173 				"Failed to get 'vccio' regulator: %d\n",
1174 				error);
1175 		return error;
1176 	}
1177 
1178 	ts->reset_gpio = devm_gpiod_get(&client->dev, "reset", GPIOD_OUT_LOW);
1179 	if (IS_ERR(ts->reset_gpio)) {
1180 		error = PTR_ERR(ts->reset_gpio);
1181 
1182 		if (error == -EPROBE_DEFER)
1183 			return error;
1184 
1185 		if (error != -ENOENT && error != -ENOSYS) {
1186 			dev_err(&client->dev,
1187 				"failed to get reset gpio: %d\n",
1188 				error);
1189 			return error;
1190 		}
1191 
1192 		ts->keep_power_in_suspend = true;
1193 	}
1194 
1195 	error = elants_i2c_power_on(ts);
1196 	if (error)
1197 		return error;
1198 
1199 	error = devm_add_action(&client->dev, elants_i2c_power_off, ts);
1200 	if (error) {
1201 		dev_err(&client->dev,
1202 			"failed to install power off action: %d\n", error);
1203 		elants_i2c_power_off(ts);
1204 		return error;
1205 	}
1206 
1207 	/* Make sure there is something at this address */
1208 	if (i2c_smbus_xfer(client->adapter, client->addr, 0,
1209 			   I2C_SMBUS_READ, 0, I2C_SMBUS_BYTE, &dummy) < 0) {
1210 		dev_err(&client->dev, "nothing at this address\n");
1211 		return -ENXIO;
1212 	}
1213 
1214 	error = elants_i2c_initialize(ts);
1215 	if (error) {
1216 		dev_err(&client->dev, "failed to initialize: %d\n", error);
1217 		return error;
1218 	}
1219 
1220 	ts->input = devm_input_allocate_device(&client->dev);
1221 	if (!ts->input) {
1222 		dev_err(&client->dev, "Failed to allocate input device\n");
1223 		return -ENOMEM;
1224 	}
1225 
1226 	ts->input->name = "Elan Touchscreen";
1227 	ts->input->id.bustype = BUS_I2C;
1228 
1229 	__set_bit(BTN_TOUCH, ts->input->keybit);
1230 	__set_bit(EV_ABS, ts->input->evbit);
1231 	__set_bit(EV_KEY, ts->input->evbit);
1232 
1233 	/* Single touch input params setup */
1234 	input_set_abs_params(ts->input, ABS_X, 0, ts->x_max, 0, 0);
1235 	input_set_abs_params(ts->input, ABS_Y, 0, ts->y_max, 0, 0);
1236 	input_set_abs_params(ts->input, ABS_PRESSURE, 0, 255, 0, 0);
1237 	input_abs_set_res(ts->input, ABS_X, ts->x_res);
1238 	input_abs_set_res(ts->input, ABS_Y, ts->y_res);
1239 
1240 	/* Multitouch input params setup */
1241 	error = input_mt_init_slots(ts->input, MAX_CONTACT_NUM,
1242 				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
1243 	if (error) {
1244 		dev_err(&client->dev,
1245 			"failed to initialize MT slots: %d\n", error);
1246 		return error;
1247 	}
1248 
1249 	input_set_abs_params(ts->input, ABS_MT_POSITION_X, 0, ts->x_max, 0, 0);
1250 	input_set_abs_params(ts->input, ABS_MT_POSITION_Y, 0, ts->y_max, 0, 0);
1251 	input_set_abs_params(ts->input, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);
1252 	input_set_abs_params(ts->input, ABS_MT_PRESSURE, 0, 255, 0, 0);
1253 	input_abs_set_res(ts->input, ABS_MT_POSITION_X, ts->x_res);
1254 	input_abs_set_res(ts->input, ABS_MT_POSITION_Y, ts->y_res);
1255 
1256 	error = input_register_device(ts->input);
1257 	if (error) {
1258 		dev_err(&client->dev,
1259 			"unable to register input device: %d\n", error);
1260 		return error;
1261 	}
1262 
1263 	/*
1264 	 * Platform code (ACPI, DTS) should normally set up interrupt
1265 	 * for us, but in case it did not let's fall back to using falling
1266 	 * edge to be compatible with older Chromebooks.
1267 	 */
1268 	irqflags = irq_get_trigger_type(client->irq);
1269 	if (!irqflags)
1270 		irqflags = IRQF_TRIGGER_FALLING;
1271 
1272 	error = devm_request_threaded_irq(&client->dev, client->irq,
1273 					  NULL, elants_i2c_irq,
1274 					  irqflags | IRQF_ONESHOT,
1275 					  client->name, ts);
1276 	if (error) {
1277 		dev_err(&client->dev, "Failed to register interrupt\n");
1278 		return error;
1279 	}
1280 
1281 	/*
1282 	 * Systems using device tree should set up wakeup via DTS,
1283 	 * the rest will configure device as wakeup source by default.
1284 	 */
1285 	if (!client->dev.of_node)
1286 		device_init_wakeup(&client->dev, true);
1287 
1288 	error = devm_device_add_group(&client->dev, &elants_attribute_group);
1289 	if (error) {
1290 		dev_err(&client->dev, "failed to create sysfs attributes: %d\n",
1291 			error);
1292 		return error;
1293 	}
1294 
1295 	return 0;
1296 }
1297 
1298 static int __maybe_unused elants_i2c_suspend(struct device *dev)
1299 {
1300 	struct i2c_client *client = to_i2c_client(dev);
1301 	struct elants_data *ts = i2c_get_clientdata(client);
1302 	const u8 set_sleep_cmd[] = { 0x54, 0x50, 0x00, 0x01 };
1303 	int retry_cnt;
1304 	int error;
1305 
1306 	/* Command not support in IAP recovery mode */
1307 	if (ts->iap_mode != ELAN_IAP_OPERATIONAL)
1308 		return -EBUSY;
1309 
1310 	disable_irq(client->irq);
1311 
1312 	if (device_may_wakeup(dev)) {
1313 		/*
1314 		 * The device will automatically enter idle mode
1315 		 * that has reduced power consumption.
1316 		 */
1317 		ts->wake_irq_enabled = (enable_irq_wake(client->irq) == 0);
1318 	} else if (ts->keep_power_in_suspend) {
1319 		for (retry_cnt = 0; retry_cnt < MAX_RETRIES; retry_cnt++) {
1320 			error = elants_i2c_send(client, set_sleep_cmd,
1321 						sizeof(set_sleep_cmd));
1322 			if (!error)
1323 				break;
1324 
1325 			dev_err(&client->dev,
1326 				"suspend command failed: %d\n", error);
1327 		}
1328 	} else {
1329 		elants_i2c_power_off(ts);
1330 	}
1331 
1332 	return 0;
1333 }
1334 
1335 static int __maybe_unused elants_i2c_resume(struct device *dev)
1336 {
1337 	struct i2c_client *client = to_i2c_client(dev);
1338 	struct elants_data *ts = i2c_get_clientdata(client);
1339 	const u8 set_active_cmd[] = { 0x54, 0x58, 0x00, 0x01 };
1340 	int retry_cnt;
1341 	int error;
1342 
1343 	if (device_may_wakeup(dev)) {
1344 		if (ts->wake_irq_enabled)
1345 			disable_irq_wake(client->irq);
1346 		elants_i2c_sw_reset(client);
1347 	} else if (ts->keep_power_in_suspend) {
1348 		for (retry_cnt = 0; retry_cnt < MAX_RETRIES; retry_cnt++) {
1349 			error = elants_i2c_send(client, set_active_cmd,
1350 						sizeof(set_active_cmd));
1351 			if (!error)
1352 				break;
1353 
1354 			dev_err(&client->dev,
1355 				"resume command failed: %d\n", error);
1356 		}
1357 	} else {
1358 		elants_i2c_power_on(ts);
1359 		elants_i2c_initialize(ts);
1360 	}
1361 
1362 	ts->state = ELAN_STATE_NORMAL;
1363 	enable_irq(client->irq);
1364 
1365 	return 0;
1366 }
1367 
1368 static SIMPLE_DEV_PM_OPS(elants_i2c_pm_ops,
1369 			 elants_i2c_suspend, elants_i2c_resume);
1370 
1371 static const struct i2c_device_id elants_i2c_id[] = {
1372 	{ DEVICE_NAME, 0 },
1373 	{ }
1374 };
1375 MODULE_DEVICE_TABLE(i2c, elants_i2c_id);
1376 
1377 #ifdef CONFIG_ACPI
1378 static const struct acpi_device_id elants_acpi_id[] = {
1379 	{ "ELAN0001", 0 },
1380 	{ }
1381 };
1382 MODULE_DEVICE_TABLE(acpi, elants_acpi_id);
1383 #endif
1384 
1385 #ifdef CONFIG_OF
1386 static const struct of_device_id elants_of_match[] = {
1387 	{ .compatible = "elan,ekth3500" },
1388 	{ /* sentinel */ }
1389 };
1390 MODULE_DEVICE_TABLE(of, elants_of_match);
1391 #endif
1392 
1393 static struct i2c_driver elants_i2c_driver = {
1394 	.probe = elants_i2c_probe,
1395 	.id_table = elants_i2c_id,
1396 	.driver = {
1397 		.name = DEVICE_NAME,
1398 		.pm = &elants_i2c_pm_ops,
1399 		.acpi_match_table = ACPI_PTR(elants_acpi_id),
1400 		.of_match_table = of_match_ptr(elants_of_match),
1401 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
1402 	},
1403 };
1404 module_i2c_driver(elants_i2c_driver);
1405 
1406 MODULE_AUTHOR("Scott Liu <scott.liu@emc.com.tw>");
1407 MODULE_DESCRIPTION("Elan I2c Touchscreen driver");
1408 MODULE_LICENSE("GPL");
1409