xref: /openbmc/linux/drivers/input/mouse/elantech.c (revision df2634f43f5106947f3735a0b61a6527a4b278cd)
1 /*
2  * Elantech Touchpad driver (v6)
3  *
4  * Copyright (C) 2007-2009 Arjan Opmeer <arjan@opmeer.net>
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License version 2 as published
8  * by the Free Software Foundation.
9  *
10  * Trademarks are the property of their respective owners.
11  */
12 
13 #define pr_fmt(fmt) KBUILD_BASENAME ": " fmt
14 
15 #include <linux/delay.h>
16 #include <linux/slab.h>
17 #include <linux/module.h>
18 #include <linux/input.h>
19 #include <linux/serio.h>
20 #include <linux/libps2.h>
21 #include "psmouse.h"
22 #include "elantech.h"
23 
24 #define elantech_debug(fmt, ...)					\
25 	do {								\
26 		if (etd->debug)						\
27 			printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__);	\
28 	} while (0)
29 
30 static bool force_elantech;
31 module_param_named(force_elantech, force_elantech, bool, 0644);
32 MODULE_PARM_DESC(force_elantech, "Force the Elantech PS/2 protocol extension to be used, 1 = enabled, 0 = disabled (default).");
33 
34 /*
35  * Send a Synaptics style sliced query command
36  */
37 static int synaptics_send_cmd(struct psmouse *psmouse, unsigned char c,
38 				unsigned char *param)
39 {
40 	if (psmouse_sliced_command(psmouse, c) ||
41 	    ps2_command(&psmouse->ps2dev, param, PSMOUSE_CMD_GETINFO)) {
42 		pr_err("synaptics_send_cmd query 0x%02x failed.\n", c);
43 		return -1;
44 	}
45 
46 	return 0;
47 }
48 
49 /*
50  * A retrying version of ps2_command
51  */
52 static int elantech_ps2_command(struct psmouse *psmouse,
53 				unsigned char *param, int command)
54 {
55 	struct ps2dev *ps2dev = &psmouse->ps2dev;
56 	struct elantech_data *etd = psmouse->private;
57 	int rc;
58 	int tries = ETP_PS2_COMMAND_TRIES;
59 
60 	do {
61 		rc = ps2_command(ps2dev, param, command);
62 		if (rc == 0)
63 			break;
64 		tries--;
65 		elantech_debug("retrying ps2 command 0x%02x (%d).\n",
66 				command, tries);
67 		msleep(ETP_PS2_COMMAND_DELAY);
68 	} while (tries > 0);
69 
70 	if (rc)
71 		pr_err("ps2 command 0x%02x failed.\n", command);
72 
73 	return rc;
74 }
75 
76 /*
77  * Send an Elantech style special command to read a value from a register
78  */
79 static int elantech_read_reg(struct psmouse *psmouse, unsigned char reg,
80 				unsigned char *val)
81 {
82 	struct elantech_data *etd = psmouse->private;
83 	unsigned char param[3];
84 	int rc = 0;
85 
86 	if (reg < 0x10 || reg > 0x26)
87 		return -1;
88 
89 	if (reg > 0x11 && reg < 0x20)
90 		return -1;
91 
92 	switch (etd->hw_version) {
93 	case 1:
94 		if (psmouse_sliced_command(psmouse, ETP_REGISTER_READ) ||
95 		    psmouse_sliced_command(psmouse, reg) ||
96 		    ps2_command(&psmouse->ps2dev, param, PSMOUSE_CMD_GETINFO)) {
97 			rc = -1;
98 		}
99 		break;
100 
101 	case 2:
102 		if (elantech_ps2_command(psmouse,  NULL, ETP_PS2_CUSTOM_COMMAND) ||
103 		    elantech_ps2_command(psmouse,  NULL, ETP_REGISTER_READ) ||
104 		    elantech_ps2_command(psmouse,  NULL, ETP_PS2_CUSTOM_COMMAND) ||
105 		    elantech_ps2_command(psmouse,  NULL, reg) ||
106 		    elantech_ps2_command(psmouse, param, PSMOUSE_CMD_GETINFO)) {
107 			rc = -1;
108 		}
109 		break;
110 	}
111 
112 	if (rc)
113 		pr_err("failed to read register 0x%02x.\n", reg);
114 	else
115 		*val = param[0];
116 
117 	return rc;
118 }
119 
120 /*
121  * Send an Elantech style special command to write a register with a value
122  */
123 static int elantech_write_reg(struct psmouse *psmouse, unsigned char reg,
124 				unsigned char val)
125 {
126 	struct elantech_data *etd = psmouse->private;
127 	int rc = 0;
128 
129 	if (reg < 0x10 || reg > 0x26)
130 		return -1;
131 
132 	if (reg > 0x11 && reg < 0x20)
133 		return -1;
134 
135 	switch (etd->hw_version) {
136 	case 1:
137 		if (psmouse_sliced_command(psmouse, ETP_REGISTER_WRITE) ||
138 		    psmouse_sliced_command(psmouse, reg) ||
139 		    psmouse_sliced_command(psmouse, val) ||
140 		    ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_SETSCALE11)) {
141 			rc = -1;
142 		}
143 		break;
144 
145 	case 2:
146 		if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
147 		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_WRITE) ||
148 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
149 		    elantech_ps2_command(psmouse, NULL, reg) ||
150 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
151 		    elantech_ps2_command(psmouse, NULL, val) ||
152 		    elantech_ps2_command(psmouse, NULL, PSMOUSE_CMD_SETSCALE11)) {
153 			rc = -1;
154 		}
155 		break;
156 	}
157 
158 	if (rc)
159 		pr_err("failed to write register 0x%02x with value 0x%02x.\n",
160 			reg, val);
161 
162 	return rc;
163 }
164 
165 /*
166  * Dump a complete mouse movement packet to the syslog
167  */
168 static void elantech_packet_dump(unsigned char *packet, int size)
169 {
170 	int	i;
171 
172 	printk(KERN_DEBUG pr_fmt("PS/2 packet ["));
173 	for (i = 0; i < size; i++)
174 		printk("%s0x%02x ", (i) ? ", " : " ", packet[i]);
175 	printk("]\n");
176 }
177 
178 /*
179  * Interpret complete data packets and report absolute mode input events for
180  * hardware version 1. (4 byte packets)
181  */
182 static void elantech_report_absolute_v1(struct psmouse *psmouse)
183 {
184 	struct input_dev *dev = psmouse->dev;
185 	struct elantech_data *etd = psmouse->private;
186 	unsigned char *packet = psmouse->packet;
187 	int fingers;
188 
189 	if (etd->fw_version < 0x020000) {
190 		/*
191 		 * byte 0:  D   U  p1  p2   1  p3   R   L
192 		 * byte 1:  f   0  th  tw  x9  x8  y9  y8
193 		 */
194 		fingers = ((packet[1] & 0x80) >> 7) +
195 				((packet[1] & 0x30) >> 4);
196 	} else {
197 		/*
198 		 * byte 0: n1  n0  p2  p1   1  p3   R   L
199 		 * byte 1:  0   0   0   0  x9  x8  y9  y8
200 		 */
201 		fingers = (packet[0] & 0xc0) >> 6;
202 	}
203 
204 	if (etd->jumpy_cursor) {
205 		if (fingers != 1) {
206 			etd->single_finger_reports = 0;
207 		} else if (etd->single_finger_reports < 2) {
208 			/* Discard first 2 reports of one finger, bogus */
209 			etd->single_finger_reports++;
210 			elantech_debug("discarding packet\n");
211 			return;
212 		}
213 	}
214 
215 	input_report_key(dev, BTN_TOUCH, fingers != 0);
216 
217 	/*
218 	 * byte 2: x7  x6  x5  x4  x3  x2  x1  x0
219 	 * byte 3: y7  y6  y5  y4  y3  y2  y1  y0
220 	 */
221 	if (fingers) {
222 		input_report_abs(dev, ABS_X,
223 			((packet[1] & 0x0c) << 6) | packet[2]);
224 		input_report_abs(dev, ABS_Y,
225 			ETP_YMAX_V1 - (((packet[1] & 0x03) << 8) | packet[3]));
226 	}
227 
228 	input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
229 	input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
230 	input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);
231 	input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
232 	input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);
233 
234 	if (etd->fw_version < 0x020000 &&
235 	    (etd->capabilities & ETP_CAP_HAS_ROCKER)) {
236 		/* rocker up */
237 		input_report_key(dev, BTN_FORWARD, packet[0] & 0x40);
238 		/* rocker down */
239 		input_report_key(dev, BTN_BACK, packet[0] & 0x80);
240 	}
241 
242 	input_sync(dev);
243 }
244 
245 /*
246  * Interpret complete data packets and report absolute mode input events for
247  * hardware version 2. (6 byte packets)
248  */
249 static void elantech_report_absolute_v2(struct psmouse *psmouse)
250 {
251 	struct input_dev *dev = psmouse->dev;
252 	unsigned char *packet = psmouse->packet;
253 	int fingers, x1, y1, x2, y2;
254 
255 	/* byte 0: n1  n0   .   .   .   .   R   L */
256 	fingers = (packet[0] & 0xc0) >> 6;
257 	input_report_key(dev, BTN_TOUCH, fingers != 0);
258 
259 	switch (fingers) {
260 	case 3:
261 		/*
262 		 * Same as one finger, except report of more than 3 fingers:
263 		 * byte 3:  n4  .   w1  w0   .   .   .   .
264 		 */
265 		if (packet[3] & 0x80)
266 			fingers = 4;
267 		/* pass through... */
268 	case 1:
269 		/*
270 		 * byte 1:  .   .   .   .   .  x10 x9  x8
271 		 * byte 2: x7  x6  x5  x4  x4  x2  x1  x0
272 		 */
273 		input_report_abs(dev, ABS_X,
274 			((packet[1] & 0x07) << 8) | packet[2]);
275 		/*
276 		 * byte 4:  .   .   .   .   .   .  y9  y8
277 		 * byte 5: y7  y6  y5  y4  y3  y2  y1  y0
278 		 */
279 		input_report_abs(dev, ABS_Y,
280 			ETP_YMAX_V2 - (((packet[4] & 0x03) << 8) | packet[5]));
281 		break;
282 
283 	case 2:
284 		/*
285 		 * The coordinate of each finger is reported separately
286 		 * with a lower resolution for two finger touches:
287 		 * byte 0:  .   .  ay8 ax8  .   .   .   .
288 		 * byte 1: ax7 ax6 ax5 ax4 ax3 ax2 ax1 ax0
289 		 */
290 		x1 = ((packet[0] & 0x10) << 4) | packet[1];
291 		/* byte 2: ay7 ay6 ay5 ay4 ay3 ay2 ay1 ay0 */
292 		y1 = ETP_2FT_YMAX - (((packet[0] & 0x20) << 3) | packet[2]);
293 		/*
294 		 * byte 3:  .   .  by8 bx8  .   .   .   .
295 		 * byte 4: bx7 bx6 bx5 bx4 bx3 bx2 bx1 bx0
296 		 */
297 		x2 = ((packet[3] & 0x10) << 4) | packet[4];
298 		/* byte 5: by7 by8 by5 by4 by3 by2 by1 by0 */
299 		y2 = ETP_2FT_YMAX - (((packet[3] & 0x20) << 3) | packet[5]);
300 		/*
301 		 * For compatibility with the X Synaptics driver scale up
302 		 * one coordinate and report as ordinary mouse movent
303 		 */
304 		input_report_abs(dev, ABS_X, x1 << 2);
305 		input_report_abs(dev, ABS_Y, y1 << 2);
306 		/*
307 		 * For compatibility with the proprietary X Elantech driver
308 		 * report both coordinates as hat coordinates
309 		 */
310 		input_report_abs(dev, ABS_HAT0X, x1);
311 		input_report_abs(dev, ABS_HAT0Y, y1);
312 		input_report_abs(dev, ABS_HAT1X, x2);
313 		input_report_abs(dev, ABS_HAT1Y, y2);
314 		break;
315 	}
316 
317 	input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
318 	input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
319 	input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);
320 	input_report_key(dev, BTN_TOOL_QUADTAP, fingers == 4);
321 	input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
322 	input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);
323 
324 	input_sync(dev);
325 }
326 
327 static int elantech_check_parity_v1(struct psmouse *psmouse)
328 {
329 	struct elantech_data *etd = psmouse->private;
330 	unsigned char *packet = psmouse->packet;
331 	unsigned char p1, p2, p3;
332 
333 	/* Parity bits are placed differently */
334 	if (etd->fw_version < 0x020000) {
335 		/* byte 0:  D   U  p1  p2   1  p3   R   L */
336 		p1 = (packet[0] & 0x20) >> 5;
337 		p2 = (packet[0] & 0x10) >> 4;
338 	} else {
339 		/* byte 0: n1  n0  p2  p1   1  p3   R   L */
340 		p1 = (packet[0] & 0x10) >> 4;
341 		p2 = (packet[0] & 0x20) >> 5;
342 	}
343 
344 	p3 = (packet[0] & 0x04) >> 2;
345 
346 	return etd->parity[packet[1]] == p1 &&
347 	       etd->parity[packet[2]] == p2 &&
348 	       etd->parity[packet[3]] == p3;
349 }
350 
351 /*
352  * Process byte stream from mouse and handle complete packets
353  */
354 static psmouse_ret_t elantech_process_byte(struct psmouse *psmouse)
355 {
356 	struct elantech_data *etd = psmouse->private;
357 
358 	if (psmouse->pktcnt < psmouse->pktsize)
359 		return PSMOUSE_GOOD_DATA;
360 
361 	if (etd->debug > 1)
362 		elantech_packet_dump(psmouse->packet, psmouse->pktsize);
363 
364 	switch (etd->hw_version) {
365 	case 1:
366 		if (etd->paritycheck && !elantech_check_parity_v1(psmouse))
367 			return PSMOUSE_BAD_DATA;
368 
369 		elantech_report_absolute_v1(psmouse);
370 		break;
371 
372 	case 2:
373 		/* We don't know how to check parity in protocol v2 */
374 		elantech_report_absolute_v2(psmouse);
375 		break;
376 	}
377 
378 	return PSMOUSE_FULL_PACKET;
379 }
380 
381 /*
382  * Put the touchpad into absolute mode
383  */
384 static int elantech_set_absolute_mode(struct psmouse *psmouse)
385 {
386 	struct elantech_data *etd = psmouse->private;
387 	unsigned char val;
388 	int tries = ETP_READ_BACK_TRIES;
389 	int rc = 0;
390 
391 	switch (etd->hw_version) {
392 	case 1:
393 		etd->reg_10 = 0x16;
394 		etd->reg_11 = 0x8f;
395 		if (elantech_write_reg(psmouse, 0x10, etd->reg_10) ||
396 		    elantech_write_reg(psmouse, 0x11, etd->reg_11)) {
397 			rc = -1;
398 		}
399 		break;
400 
401 	case 2:
402 					/* Windows driver values */
403 		etd->reg_10 = 0x54;
404 		etd->reg_11 = 0x88;	/* 0x8a */
405 		etd->reg_21 = 0x60;	/* 0x00 */
406 		if (elantech_write_reg(psmouse, 0x10, etd->reg_10) ||
407 		    elantech_write_reg(psmouse, 0x11, etd->reg_11) ||
408 		    elantech_write_reg(psmouse, 0x21, etd->reg_21)) {
409 			rc = -1;
410 			break;
411 		}
412 	}
413 
414 	if (rc == 0) {
415 		/*
416 		 * Read back reg 0x10. For hardware version 1 we must make
417 		 * sure the absolute mode bit is set. For hardware version 2
418 		 * the touchpad is probably initalising and not ready until
419 		 * we read back the value we just wrote.
420 		 */
421 		do {
422 			rc = elantech_read_reg(psmouse, 0x10, &val);
423 			if (rc == 0)
424 				break;
425 			tries--;
426 			elantech_debug("retrying read (%d).\n", tries);
427 			msleep(ETP_READ_BACK_DELAY);
428 		} while (tries > 0);
429 
430 		if (rc) {
431 			pr_err("failed to read back register 0x10.\n");
432 		} else if (etd->hw_version == 1 &&
433 			   !(val & ETP_R10_ABSOLUTE_MODE)) {
434 			pr_err("touchpad refuses to switch to absolute mode.\n");
435 			rc = -1;
436 		}
437 	}
438 
439 	if (rc)
440 		pr_err("failed to initialise registers.\n");
441 
442 	return rc;
443 }
444 
445 /*
446  * Set the appropriate event bits for the input subsystem
447  */
448 static void elantech_set_input_params(struct psmouse *psmouse)
449 {
450 	struct input_dev *dev = psmouse->dev;
451 	struct elantech_data *etd = psmouse->private;
452 
453 	__set_bit(EV_KEY, dev->evbit);
454 	__set_bit(EV_ABS, dev->evbit);
455 	__clear_bit(EV_REL, dev->evbit);
456 
457 	__set_bit(BTN_LEFT, dev->keybit);
458 	__set_bit(BTN_RIGHT, dev->keybit);
459 
460 	__set_bit(BTN_TOUCH, dev->keybit);
461 	__set_bit(BTN_TOOL_FINGER, dev->keybit);
462 	__set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
463 	__set_bit(BTN_TOOL_TRIPLETAP, dev->keybit);
464 
465 	switch (etd->hw_version) {
466 	case 1:
467 		/* Rocker button */
468 		if (etd->fw_version < 0x020000 &&
469 		    (etd->capabilities & ETP_CAP_HAS_ROCKER)) {
470 			__set_bit(BTN_FORWARD, dev->keybit);
471 			__set_bit(BTN_BACK, dev->keybit);
472 		}
473 		input_set_abs_params(dev, ABS_X, ETP_XMIN_V1, ETP_XMAX_V1, 0, 0);
474 		input_set_abs_params(dev, ABS_Y, ETP_YMIN_V1, ETP_YMAX_V1, 0, 0);
475 		break;
476 
477 	case 2:
478 		__set_bit(BTN_TOOL_QUADTAP, dev->keybit);
479 		input_set_abs_params(dev, ABS_X, ETP_XMIN_V2, ETP_XMAX_V2, 0, 0);
480 		input_set_abs_params(dev, ABS_Y, ETP_YMIN_V2, ETP_YMAX_V2, 0, 0);
481 		input_set_abs_params(dev, ABS_HAT0X, ETP_2FT_XMIN, ETP_2FT_XMAX, 0, 0);
482 		input_set_abs_params(dev, ABS_HAT0Y, ETP_2FT_YMIN, ETP_2FT_YMAX, 0, 0);
483 		input_set_abs_params(dev, ABS_HAT1X, ETP_2FT_XMIN, ETP_2FT_XMAX, 0, 0);
484 		input_set_abs_params(dev, ABS_HAT1Y, ETP_2FT_YMIN, ETP_2FT_YMAX, 0, 0);
485 		break;
486 	}
487 }
488 
489 struct elantech_attr_data {
490 	size_t		field_offset;
491 	unsigned char	reg;
492 };
493 
494 /*
495  * Display a register value by reading a sysfs entry
496  */
497 static ssize_t elantech_show_int_attr(struct psmouse *psmouse, void *data,
498 					char *buf)
499 {
500 	struct elantech_data *etd = psmouse->private;
501 	struct elantech_attr_data *attr = data;
502 	unsigned char *reg = (unsigned char *) etd + attr->field_offset;
503 	int rc = 0;
504 
505 	if (attr->reg)
506 		rc = elantech_read_reg(psmouse, attr->reg, reg);
507 
508 	return sprintf(buf, "0x%02x\n", (attr->reg && rc) ? -1 : *reg);
509 }
510 
511 /*
512  * Write a register value by writing a sysfs entry
513  */
514 static ssize_t elantech_set_int_attr(struct psmouse *psmouse,
515 				     void *data, const char *buf, size_t count)
516 {
517 	struct elantech_data *etd = psmouse->private;
518 	struct elantech_attr_data *attr = data;
519 	unsigned char *reg = (unsigned char *) etd + attr->field_offset;
520 	unsigned long value;
521 	int err;
522 
523 	err = strict_strtoul(buf, 16, &value);
524 	if (err)
525 		return err;
526 
527 	if (value > 0xff)
528 		return -EINVAL;
529 
530 	/* Do we need to preserve some bits for version 2 hardware too? */
531 	if (etd->hw_version == 1) {
532 		if (attr->reg == 0x10)
533 			/* Force absolute mode always on */
534 			value |= ETP_R10_ABSOLUTE_MODE;
535 		else if (attr->reg == 0x11)
536 			/* Force 4 byte mode always on */
537 			value |= ETP_R11_4_BYTE_MODE;
538 	}
539 
540 	if (!attr->reg || elantech_write_reg(psmouse, attr->reg, value) == 0)
541 		*reg = value;
542 
543 	return count;
544 }
545 
546 #define ELANTECH_INT_ATTR(_name, _register)				\
547 	static struct elantech_attr_data elantech_attr_##_name = {	\
548 		.field_offset = offsetof(struct elantech_data, _name),	\
549 		.reg = _register,					\
550 	};								\
551 	PSMOUSE_DEFINE_ATTR(_name, S_IWUSR | S_IRUGO,			\
552 			    &elantech_attr_##_name,			\
553 			    elantech_show_int_attr,			\
554 			    elantech_set_int_attr)
555 
556 ELANTECH_INT_ATTR(reg_10, 0x10);
557 ELANTECH_INT_ATTR(reg_11, 0x11);
558 ELANTECH_INT_ATTR(reg_20, 0x20);
559 ELANTECH_INT_ATTR(reg_21, 0x21);
560 ELANTECH_INT_ATTR(reg_22, 0x22);
561 ELANTECH_INT_ATTR(reg_23, 0x23);
562 ELANTECH_INT_ATTR(reg_24, 0x24);
563 ELANTECH_INT_ATTR(reg_25, 0x25);
564 ELANTECH_INT_ATTR(reg_26, 0x26);
565 ELANTECH_INT_ATTR(debug, 0);
566 ELANTECH_INT_ATTR(paritycheck, 0);
567 
568 static struct attribute *elantech_attrs[] = {
569 	&psmouse_attr_reg_10.dattr.attr,
570 	&psmouse_attr_reg_11.dattr.attr,
571 	&psmouse_attr_reg_20.dattr.attr,
572 	&psmouse_attr_reg_21.dattr.attr,
573 	&psmouse_attr_reg_22.dattr.attr,
574 	&psmouse_attr_reg_23.dattr.attr,
575 	&psmouse_attr_reg_24.dattr.attr,
576 	&psmouse_attr_reg_25.dattr.attr,
577 	&psmouse_attr_reg_26.dattr.attr,
578 	&psmouse_attr_debug.dattr.attr,
579 	&psmouse_attr_paritycheck.dattr.attr,
580 	NULL
581 };
582 
583 static struct attribute_group elantech_attr_group = {
584 	.attrs = elantech_attrs,
585 };
586 
587 static bool elantech_is_signature_valid(const unsigned char *param)
588 {
589 	static const unsigned char rates[] = { 200, 100, 80, 60, 40, 20, 10 };
590 	int i;
591 
592 	if (param[0] == 0)
593 		return false;
594 
595 	if (param[1] == 0)
596 		return true;
597 
598 	for (i = 0; i < ARRAY_SIZE(rates); i++)
599 		if (param[2] == rates[i])
600 			return false;
601 
602 	return true;
603 }
604 
605 /*
606  * Use magic knock to detect Elantech touchpad
607  */
608 int elantech_detect(struct psmouse *psmouse, bool set_properties)
609 {
610 	struct ps2dev *ps2dev = &psmouse->ps2dev;
611 	unsigned char param[3];
612 
613 	ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_RESET_DIS);
614 
615 	if (ps2_command(ps2dev,  NULL, PSMOUSE_CMD_DISABLE) ||
616 	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
617 	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
618 	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
619 	    ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO)) {
620 		pr_debug("sending Elantech magic knock failed.\n");
621 		return -1;
622 	}
623 
624 	/*
625 	 * Report this in case there are Elantech models that use a different
626 	 * set of magic numbers
627 	 */
628 	if (param[0] != 0x3c || param[1] != 0x03 || param[2] != 0xc8) {
629 		pr_debug("unexpected magic knock result 0x%02x, 0x%02x, 0x%02x.\n",
630 			 param[0], param[1], param[2]);
631 		return -1;
632 	}
633 
634 	/*
635 	 * Query touchpad's firmware version and see if it reports known
636 	 * value to avoid mis-detection. Logitech mice are known to respond
637 	 * to Elantech magic knock and there might be more.
638 	 */
639 	if (synaptics_send_cmd(psmouse, ETP_FW_VERSION_QUERY, param)) {
640 		pr_debug("failed to query firmware version.\n");
641 		return -1;
642 	}
643 
644 	pr_debug("Elantech version query result 0x%02x, 0x%02x, 0x%02x.\n",
645 		 param[0], param[1], param[2]);
646 
647 	if (!elantech_is_signature_valid(param)) {
648 		if (!force_elantech) {
649 			pr_debug("Probably not a real Elantech touchpad. Aborting.\n");
650 			return -1;
651 		}
652 
653 		pr_debug("Probably not a real Elantech touchpad. Enabling anyway due to force_elantech.\n");
654 	}
655 
656 	if (set_properties) {
657 		psmouse->vendor = "Elantech";
658 		psmouse->name = "Touchpad";
659 	}
660 
661 	return 0;
662 }
663 
664 /*
665  * Clean up sysfs entries when disconnecting
666  */
667 static void elantech_disconnect(struct psmouse *psmouse)
668 {
669 	sysfs_remove_group(&psmouse->ps2dev.serio->dev.kobj,
670 			   &elantech_attr_group);
671 	kfree(psmouse->private);
672 	psmouse->private = NULL;
673 }
674 
675 /*
676  * Put the touchpad back into absolute mode when reconnecting
677  */
678 static int elantech_reconnect(struct psmouse *psmouse)
679 {
680 	if (elantech_detect(psmouse, 0))
681 		return -1;
682 
683 	if (elantech_set_absolute_mode(psmouse)) {
684 		pr_err("failed to put touchpad back into absolute mode.\n");
685 		return -1;
686 	}
687 
688 	return 0;
689 }
690 
691 /*
692  * Initialize the touchpad and create sysfs entries
693  */
694 int elantech_init(struct psmouse *psmouse)
695 {
696 	struct elantech_data *etd;
697 	int i, error;
698 	unsigned char param[3];
699 
700 	psmouse->private = etd = kzalloc(sizeof(struct elantech_data), GFP_KERNEL);
701 	if (!etd)
702 		return -ENOMEM;
703 
704 	etd->parity[0] = 1;
705 	for (i = 1; i < 256; i++)
706 		etd->parity[i] = etd->parity[i & (i - 1)] ^ 1;
707 
708 	/*
709 	 * Do the version query again so we can store the result
710 	 */
711 	if (synaptics_send_cmd(psmouse, ETP_FW_VERSION_QUERY, param)) {
712 		pr_err("failed to query firmware version.\n");
713 		goto init_fail;
714 	}
715 
716 	etd->fw_version = (param[0] << 16) | (param[1] << 8) | param[2];
717 
718 	/*
719 	 * Assume every version greater than this is new EeePC style
720 	 * hardware with 6 byte packets
721 	 */
722 	if (etd->fw_version >= 0x020030) {
723 		etd->hw_version = 2;
724 		/* For now show extra debug information */
725 		etd->debug = 1;
726 		/* Don't know how to do parity checking for version 2 */
727 		etd->paritycheck = 0;
728 	} else {
729 		etd->hw_version = 1;
730 		etd->paritycheck = 1;
731 	}
732 
733 	pr_info("assuming hardware version %d, firmware version %d.%d.%d\n",
734 		etd->hw_version, param[0], param[1], param[2]);
735 
736 	if (synaptics_send_cmd(psmouse, ETP_CAPABILITIES_QUERY, param)) {
737 		pr_err("failed to query capabilities.\n");
738 		goto init_fail;
739 	}
740 	pr_info("Synaptics capabilities query result 0x%02x, 0x%02x, 0x%02x.\n",
741 		param[0], param[1], param[2]);
742 	etd->capabilities = param[0];
743 
744 	/*
745 	 * This firmware suffers from misreporting coordinates when
746 	 * a touch action starts causing the mouse cursor or scrolled page
747 	 * to jump. Enable a workaround.
748 	 */
749 	if (etd->fw_version == 0x020022 || etd->fw_version == 0x020600) {
750 		pr_info("firmware version 2.0.34/2.6.0 detected, enabling jumpy cursor workaround\n");
751 		etd->jumpy_cursor = true;
752 	}
753 
754 	if (elantech_set_absolute_mode(psmouse)) {
755 		pr_err("failed to put touchpad into absolute mode.\n");
756 		goto init_fail;
757 	}
758 
759 	elantech_set_input_params(psmouse);
760 
761 	error = sysfs_create_group(&psmouse->ps2dev.serio->dev.kobj,
762 				   &elantech_attr_group);
763 	if (error) {
764 		pr_err("failed to create sysfs attributes, error: %d.\n", error);
765 		goto init_fail;
766 	}
767 
768 	psmouse->protocol_handler = elantech_process_byte;
769 	psmouse->disconnect = elantech_disconnect;
770 	psmouse->reconnect = elantech_reconnect;
771 	psmouse->pktsize = etd->hw_version == 2 ? 6 : 4;
772 
773 	return 0;
774 
775  init_fail:
776 	kfree(etd);
777 	return -1;
778 }
779