xref: /linux/drivers/input/mouse/elantech.c (revision a33f32244d8550da8b4a26e277ce07d5c6d158b5)
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 #include <linux/delay.h>
14 #include <linux/slab.h>
15 #include <linux/module.h>
16 #include <linux/input.h>
17 #include <linux/serio.h>
18 #include <linux/libps2.h>
19 #include "psmouse.h"
20 #include "elantech.h"
21 
22 #define elantech_debug(format, arg...)				\
23 	do {							\
24 		if (etd->debug)					\
25 			printk(KERN_DEBUG format, ##arg);	\
26 	} while (0)
27 
28 /*
29  * Send a Synaptics style sliced query command
30  */
31 static int synaptics_send_cmd(struct psmouse *psmouse, unsigned char c,
32 				unsigned char *param)
33 {
34 	if (psmouse_sliced_command(psmouse, c) ||
35 	    ps2_command(&psmouse->ps2dev, param, PSMOUSE_CMD_GETINFO)) {
36 		pr_err("elantech.c: synaptics_send_cmd query 0x%02x failed.\n", c);
37 		return -1;
38 	}
39 
40 	return 0;
41 }
42 
43 /*
44  * A retrying version of ps2_command
45  */
46 static int elantech_ps2_command(struct psmouse *psmouse,
47 				unsigned char *param, int command)
48 {
49 	struct ps2dev *ps2dev = &psmouse->ps2dev;
50 	struct elantech_data *etd = psmouse->private;
51 	int rc;
52 	int tries = ETP_PS2_COMMAND_TRIES;
53 
54 	do {
55 		rc = ps2_command(ps2dev, param, command);
56 		if (rc == 0)
57 			break;
58 		tries--;
59 		elantech_debug("elantech.c: retrying ps2 command 0x%02x (%d).\n",
60 			command, tries);
61 		msleep(ETP_PS2_COMMAND_DELAY);
62 	} while (tries > 0);
63 
64 	if (rc)
65 		pr_err("elantech.c: ps2 command 0x%02x failed.\n", command);
66 
67 	return rc;
68 }
69 
70 /*
71  * Send an Elantech style special command to read a value from a register
72  */
73 static int elantech_read_reg(struct psmouse *psmouse, unsigned char reg,
74 				unsigned char *val)
75 {
76 	struct elantech_data *etd = psmouse->private;
77 	unsigned char param[3];
78 	int rc = 0;
79 
80 	if (reg < 0x10 || reg > 0x26)
81 		return -1;
82 
83 	if (reg > 0x11 && reg < 0x20)
84 		return -1;
85 
86 	switch (etd->hw_version) {
87 	case 1:
88 		if (psmouse_sliced_command(psmouse, ETP_REGISTER_READ) ||
89 		    psmouse_sliced_command(psmouse, reg) ||
90 		    ps2_command(&psmouse->ps2dev, param, PSMOUSE_CMD_GETINFO)) {
91 			rc = -1;
92 		}
93 		break;
94 
95 	case 2:
96 		if (elantech_ps2_command(psmouse,  NULL, ETP_PS2_CUSTOM_COMMAND) ||
97 		    elantech_ps2_command(psmouse,  NULL, ETP_REGISTER_READ) ||
98 		    elantech_ps2_command(psmouse,  NULL, ETP_PS2_CUSTOM_COMMAND) ||
99 		    elantech_ps2_command(psmouse,  NULL, reg) ||
100 		    elantech_ps2_command(psmouse, param, PSMOUSE_CMD_GETINFO)) {
101 			rc = -1;
102 		}
103 		break;
104 	}
105 
106 	if (rc)
107 		pr_err("elantech.c: failed to read register 0x%02x.\n", reg);
108 	else
109 		*val = param[0];
110 
111 	return rc;
112 }
113 
114 /*
115  * Send an Elantech style special command to write a register with a value
116  */
117 static int elantech_write_reg(struct psmouse *psmouse, unsigned char reg,
118 				unsigned char val)
119 {
120 	struct elantech_data *etd = psmouse->private;
121 	int rc = 0;
122 
123 	if (reg < 0x10 || reg > 0x26)
124 		return -1;
125 
126 	if (reg > 0x11 && reg < 0x20)
127 		return -1;
128 
129 	switch (etd->hw_version) {
130 	case 1:
131 		if (psmouse_sliced_command(psmouse, ETP_REGISTER_WRITE) ||
132 		    psmouse_sliced_command(psmouse, reg) ||
133 		    psmouse_sliced_command(psmouse, val) ||
134 		    ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_SETSCALE11)) {
135 			rc = -1;
136 		}
137 		break;
138 
139 	case 2:
140 		if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
141 		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_WRITE) ||
142 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
143 		    elantech_ps2_command(psmouse, NULL, reg) ||
144 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
145 		    elantech_ps2_command(psmouse, NULL, val) ||
146 		    elantech_ps2_command(psmouse, NULL, PSMOUSE_CMD_SETSCALE11)) {
147 			rc = -1;
148 		}
149 		break;
150 	}
151 
152 	if (rc)
153 		pr_err("elantech.c: failed to write register 0x%02x with value 0x%02x.\n",
154 			reg, val);
155 
156 	return rc;
157 }
158 
159 /*
160  * Dump a complete mouse movement packet to the syslog
161  */
162 static void elantech_packet_dump(unsigned char *packet, int size)
163 {
164 	int	i;
165 
166 	printk(KERN_DEBUG "elantech.c: PS/2 packet [");
167 	for (i = 0; i < size; i++)
168 		printk("%s0x%02x ", (i) ? ", " : " ", packet[i]);
169 	printk("]\n");
170 }
171 
172 /*
173  * Interpret complete data packets and report absolute mode input events for
174  * hardware version 1. (4 byte packets)
175  */
176 static void elantech_report_absolute_v1(struct psmouse *psmouse)
177 {
178 	struct input_dev *dev = psmouse->dev;
179 	struct elantech_data *etd = psmouse->private;
180 	unsigned char *packet = psmouse->packet;
181 	int fingers;
182 	static int old_fingers;
183 
184 	if (etd->fw_version_maj == 0x01) {
185 		/* byte 0:  D   U  p1  p2   1  p3   R   L
186 		   byte 1:  f   0  th  tw  x9  x8  y9  y8 */
187 		fingers = ((packet[1] & 0x80) >> 7) +
188 				((packet[1] & 0x30) >> 4);
189 	} else {
190 		/* byte 0: n1  n0  p2  p1   1  p3   R   L
191 		   byte 1:  0   0   0   0  x9  x8  y9  y8 */
192 		fingers = (packet[0] & 0xc0) >> 6;
193 	}
194 
195 	if (etd->jumpy_cursor) {
196 		/* Discard packets that are likely to have bogus coordinates */
197 		if (fingers > old_fingers) {
198 			elantech_debug("elantech.c: discarding packet\n");
199 			goto discard_packet_v1;
200 		}
201 	}
202 
203 	input_report_key(dev, BTN_TOUCH, fingers != 0);
204 
205 	/* byte 2: x7  x6  x5  x4  x3  x2  x1  x0
206 	   byte 3: y7  y6  y5  y4  y3  y2  y1  y0 */
207 	if (fingers) {
208 		input_report_abs(dev, ABS_X,
209 			((packet[1] & 0x0c) << 6) | packet[2]);
210 		input_report_abs(dev, ABS_Y, ETP_YMAX_V1 -
211 			(((packet[1] & 0x03) << 8) | packet[3]));
212 	}
213 
214 	input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
215 	input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
216 	input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);
217 	input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
218 	input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);
219 
220 	if ((etd->fw_version_maj == 0x01) &&
221 	    (etd->capabilities & ETP_CAP_HAS_ROCKER)) {
222 		/* rocker up */
223 		input_report_key(dev, BTN_FORWARD, packet[0] & 0x40);
224 		/* rocker down */
225 		input_report_key(dev, BTN_BACK, packet[0] & 0x80);
226 	}
227 
228 	input_sync(dev);
229 
230  discard_packet_v1:
231 	old_fingers = fingers;
232 }
233 
234 /*
235  * Interpret complete data packets and report absolute mode input events for
236  * hardware version 2. (6 byte packets)
237  */
238 static void elantech_report_absolute_v2(struct psmouse *psmouse)
239 {
240 	struct input_dev *dev = psmouse->dev;
241 	unsigned char *packet = psmouse->packet;
242 	int fingers, x1, y1, x2, y2;
243 
244 	/* byte 0: n1  n0   .   .   .   .   R   L */
245 	fingers = (packet[0] & 0xc0) >> 6;
246 	input_report_key(dev, BTN_TOUCH, fingers != 0);
247 
248 	switch (fingers) {
249 	case 1:
250 		/* byte 1: x15 x14 x13 x12 x11 x10 x9  x8
251 		   byte 2: x7  x6  x5  x4  x4  x2  x1  x0 */
252 		input_report_abs(dev, ABS_X, (packet[1] << 8) | packet[2]);
253 		/* byte 4: y15 y14 y13 y12 y11 y10 y8  y8
254 		   byte 5: y7  y6  y5  y4  y3  y2  y1  y0 */
255 		input_report_abs(dev, ABS_Y, ETP_YMAX_V2 -
256 			((packet[4] << 8) | packet[5]));
257 		break;
258 
259 	case 2:
260 		/* The coordinate of each finger is reported separately with
261 		   a lower resolution for two finger touches */
262 		/* byte 0:  .   .  ay8 ax8  .   .   .   .
263 		   byte 1: ax7 ax6 ax5 ax4 ax3 ax2 ax1 ax0 */
264 		x1 = ((packet[0] & 0x10) << 4) | packet[1];
265 		/* byte 2: ay7 ay6 ay5 ay4 ay3 ay2 ay1 ay0 */
266 		y1 = ETP_2FT_YMAX - (((packet[0] & 0x20) << 3) | packet[2]);
267 		/* byte 3:  .   .  by8 bx8  .   .   .   .
268 		   byte 4: bx7 bx6 bx5 bx4 bx3 bx2 bx1 bx0 */
269 		x2 = ((packet[3] & 0x10) << 4) | packet[4];
270 		/* byte 5: by7 by8 by5 by4 by3 by2 by1 by0 */
271 		y2 = ETP_2FT_YMAX - (((packet[3] & 0x20) << 3) | packet[5]);
272 		/* For compatibility with the X Synaptics driver scale up one
273 		   coordinate and report as ordinary mouse movent */
274 		input_report_abs(dev, ABS_X, x1 << 2);
275 		input_report_abs(dev, ABS_Y, y1 << 2);
276 		/* For compatibility with the proprietary X Elantech driver
277 		   report both coordinates as hat coordinates */
278 		input_report_abs(dev, ABS_HAT0X, x1);
279 		input_report_abs(dev, ABS_HAT0Y, y1);
280 		input_report_abs(dev, ABS_HAT1X, x2);
281 		input_report_abs(dev, ABS_HAT1Y, y2);
282 		break;
283 	}
284 
285 	input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
286 	input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
287 	input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);
288 	input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
289 	input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);
290 
291 	input_sync(dev);
292 }
293 
294 static int elantech_check_parity_v1(struct psmouse *psmouse)
295 {
296 	struct elantech_data *etd = psmouse->private;
297 	unsigned char *packet = psmouse->packet;
298 	unsigned char p1, p2, p3;
299 
300 	/* Parity bits are placed differently */
301 	if (etd->fw_version_maj == 0x01) {
302 		/* byte 0:  D   U  p1  p2   1  p3   R   L */
303 		p1 = (packet[0] & 0x20) >> 5;
304 		p2 = (packet[0] & 0x10) >> 4;
305 	} else {
306 		/* byte 0: n1  n0  p2  p1   1  p3   R   L */
307 		p1 = (packet[0] & 0x10) >> 4;
308 		p2 = (packet[0] & 0x20) >> 5;
309 	}
310 
311 	p3 = (packet[0] & 0x04) >> 2;
312 
313 	return etd->parity[packet[1]] == p1 &&
314 	       etd->parity[packet[2]] == p2 &&
315 	       etd->parity[packet[3]] == p3;
316 }
317 
318 /*
319  * Process byte stream from mouse and handle complete packets
320  */
321 static psmouse_ret_t elantech_process_byte(struct psmouse *psmouse)
322 {
323 	struct elantech_data *etd = psmouse->private;
324 
325 	if (psmouse->pktcnt < psmouse->pktsize)
326 		return PSMOUSE_GOOD_DATA;
327 
328 	if (etd->debug > 1)
329 		elantech_packet_dump(psmouse->packet, psmouse->pktsize);
330 
331 	switch (etd->hw_version) {
332 	case 1:
333 		if (etd->paritycheck && !elantech_check_parity_v1(psmouse))
334 			return PSMOUSE_BAD_DATA;
335 
336 		elantech_report_absolute_v1(psmouse);
337 		break;
338 
339 	case 2:
340 		/* We don't know how to check parity in protocol v2 */
341 		elantech_report_absolute_v2(psmouse);
342 		break;
343 	}
344 
345 	return PSMOUSE_FULL_PACKET;
346 }
347 
348 /*
349  * Put the touchpad into absolute mode
350  */
351 static int elantech_set_absolute_mode(struct psmouse *psmouse)
352 {
353 	struct elantech_data *etd = psmouse->private;
354 	unsigned char val;
355 	int tries = ETP_READ_BACK_TRIES;
356 	int rc = 0;
357 
358 	switch (etd->hw_version) {
359 	case 1:
360 		etd->reg_10 = 0x16;
361 		etd->reg_11 = 0x8f;
362 		if (elantech_write_reg(psmouse, 0x10, etd->reg_10) ||
363 		    elantech_write_reg(psmouse, 0x11, etd->reg_11)) {
364 			rc = -1;
365 		}
366 		break;
367 
368 	case 2:
369 					/* Windows driver values */
370 		etd->reg_10 = 0x54;
371 		etd->reg_11 = 0x88;	/* 0x8a */
372 		etd->reg_21 = 0x60;	/* 0x00 */
373 		if (elantech_write_reg(psmouse, 0x10, etd->reg_10) ||
374 		    elantech_write_reg(psmouse, 0x11, etd->reg_11) ||
375 		    elantech_write_reg(psmouse, 0x21, etd->reg_21)) {
376 			rc = -1;
377 			break;
378 		}
379 	}
380 
381 	if (rc == 0) {
382 		/*
383 		 * Read back reg 0x10. For hardware version 1 we must make
384 		 * sure the absolute mode bit is set. For hardware version 2
385 		 * the touchpad is probably initalising and not ready until
386 		 * we read back the value we just wrote.
387 		 */
388 		do {
389 			rc = elantech_read_reg(psmouse, 0x10, &val);
390 			if (rc == 0)
391 				break;
392 			tries--;
393 			elantech_debug("elantech.c: retrying read (%d).\n",
394 					tries);
395 			msleep(ETP_READ_BACK_DELAY);
396 		} while (tries > 0);
397 
398 		if (rc) {
399 			pr_err("elantech.c: failed to read back register 0x10.\n");
400 		} else if (etd->hw_version == 1 &&
401 			   !(val & ETP_R10_ABSOLUTE_MODE)) {
402 			pr_err("elantech.c: touchpad refuses "
403 				"to switch to absolute mode.\n");
404 			rc = -1;
405 		}
406 	}
407 
408 	if (rc)
409 		pr_err("elantech.c: failed to initialise registers.\n");
410 
411 	return rc;
412 }
413 
414 /*
415  * Set the appropriate event bits for the input subsystem
416  */
417 static void elantech_set_input_params(struct psmouse *psmouse)
418 {
419 	struct input_dev *dev = psmouse->dev;
420 	struct elantech_data *etd = psmouse->private;
421 
422 	__set_bit(EV_KEY, dev->evbit);
423 	__set_bit(EV_ABS, dev->evbit);
424 	__clear_bit(EV_REL, dev->evbit);
425 
426 	__set_bit(BTN_LEFT, dev->keybit);
427 	__set_bit(BTN_RIGHT, dev->keybit);
428 
429 	__set_bit(BTN_TOUCH, dev->keybit);
430 	__set_bit(BTN_TOOL_FINGER, dev->keybit);
431 	__set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
432 	__set_bit(BTN_TOOL_TRIPLETAP, dev->keybit);
433 
434 	switch (etd->hw_version) {
435 	case 1:
436 		/* Rocker button */
437 		if ((etd->fw_version_maj == 0x01) &&
438 		    (etd->capabilities & ETP_CAP_HAS_ROCKER)) {
439 			__set_bit(BTN_FORWARD, dev->keybit);
440 			__set_bit(BTN_BACK, dev->keybit);
441 		}
442 		input_set_abs_params(dev, ABS_X, ETP_XMIN_V1, ETP_XMAX_V1, 0, 0);
443 		input_set_abs_params(dev, ABS_Y, ETP_YMIN_V1, ETP_YMAX_V1, 0, 0);
444 		break;
445 
446 	case 2:
447 		input_set_abs_params(dev, ABS_X, ETP_XMIN_V2, ETP_XMAX_V2, 0, 0);
448 		input_set_abs_params(dev, ABS_Y, ETP_YMIN_V2, ETP_YMAX_V2, 0, 0);
449 		input_set_abs_params(dev, ABS_HAT0X, ETP_2FT_XMIN, ETP_2FT_XMAX, 0, 0);
450 		input_set_abs_params(dev, ABS_HAT0Y, ETP_2FT_YMIN, ETP_2FT_YMAX, 0, 0);
451 		input_set_abs_params(dev, ABS_HAT1X, ETP_2FT_XMIN, ETP_2FT_XMAX, 0, 0);
452 		input_set_abs_params(dev, ABS_HAT1Y, ETP_2FT_YMIN, ETP_2FT_YMAX, 0, 0);
453 		break;
454 	}
455 }
456 
457 struct elantech_attr_data {
458 	size_t		field_offset;
459 	unsigned char	reg;
460 };
461 
462 /*
463  * Display a register value by reading a sysfs entry
464  */
465 static ssize_t elantech_show_int_attr(struct psmouse *psmouse, void *data,
466 					char *buf)
467 {
468 	struct elantech_data *etd = psmouse->private;
469 	struct elantech_attr_data *attr = data;
470 	unsigned char *reg = (unsigned char *) etd + attr->field_offset;
471 	int rc = 0;
472 
473 	if (attr->reg)
474 		rc = elantech_read_reg(psmouse, attr->reg, reg);
475 
476 	return sprintf(buf, "0x%02x\n", (attr->reg && rc) ? -1 : *reg);
477 }
478 
479 /*
480  * Write a register value by writing a sysfs entry
481  */
482 static ssize_t elantech_set_int_attr(struct psmouse *psmouse,
483 				     void *data, const char *buf, size_t count)
484 {
485 	struct elantech_data *etd = psmouse->private;
486 	struct elantech_attr_data *attr = data;
487 	unsigned char *reg = (unsigned char *) etd + attr->field_offset;
488 	unsigned long value;
489 	int err;
490 
491 	err = strict_strtoul(buf, 16, &value);
492 	if (err)
493 		return err;
494 
495 	if (value > 0xff)
496 		return -EINVAL;
497 
498 	/* Do we need to preserve some bits for version 2 hardware too? */
499 	if (etd->hw_version == 1) {
500 		if (attr->reg == 0x10)
501 			/* Force absolute mode always on */
502 			value |= ETP_R10_ABSOLUTE_MODE;
503 		else if (attr->reg == 0x11)
504 			/* Force 4 byte mode always on */
505 			value |= ETP_R11_4_BYTE_MODE;
506 	}
507 
508 	if (!attr->reg || elantech_write_reg(psmouse, attr->reg, value) == 0)
509 		*reg = value;
510 
511 	return count;
512 }
513 
514 #define ELANTECH_INT_ATTR(_name, _register)				\
515 	static struct elantech_attr_data elantech_attr_##_name = {	\
516 		.field_offset = offsetof(struct elantech_data, _name),	\
517 		.reg = _register,					\
518 	};								\
519 	PSMOUSE_DEFINE_ATTR(_name, S_IWUSR | S_IRUGO,			\
520 			    &elantech_attr_##_name,			\
521 			    elantech_show_int_attr,			\
522 			    elantech_set_int_attr)
523 
524 ELANTECH_INT_ATTR(reg_10, 0x10);
525 ELANTECH_INT_ATTR(reg_11, 0x11);
526 ELANTECH_INT_ATTR(reg_20, 0x20);
527 ELANTECH_INT_ATTR(reg_21, 0x21);
528 ELANTECH_INT_ATTR(reg_22, 0x22);
529 ELANTECH_INT_ATTR(reg_23, 0x23);
530 ELANTECH_INT_ATTR(reg_24, 0x24);
531 ELANTECH_INT_ATTR(reg_25, 0x25);
532 ELANTECH_INT_ATTR(reg_26, 0x26);
533 ELANTECH_INT_ATTR(debug, 0);
534 ELANTECH_INT_ATTR(paritycheck, 0);
535 
536 static struct attribute *elantech_attrs[] = {
537 	&psmouse_attr_reg_10.dattr.attr,
538 	&psmouse_attr_reg_11.dattr.attr,
539 	&psmouse_attr_reg_20.dattr.attr,
540 	&psmouse_attr_reg_21.dattr.attr,
541 	&psmouse_attr_reg_22.dattr.attr,
542 	&psmouse_attr_reg_23.dattr.attr,
543 	&psmouse_attr_reg_24.dattr.attr,
544 	&psmouse_attr_reg_25.dattr.attr,
545 	&psmouse_attr_reg_26.dattr.attr,
546 	&psmouse_attr_debug.dattr.attr,
547 	&psmouse_attr_paritycheck.dattr.attr,
548 	NULL
549 };
550 
551 static struct attribute_group elantech_attr_group = {
552 	.attrs = elantech_attrs,
553 };
554 
555 /*
556  * Use magic knock to detect Elantech touchpad
557  */
558 int elantech_detect(struct psmouse *psmouse, bool set_properties)
559 {
560 	struct ps2dev *ps2dev = &psmouse->ps2dev;
561 	unsigned char param[3];
562 
563 	ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_RESET_DIS);
564 
565 	if (ps2_command(ps2dev,  NULL, PSMOUSE_CMD_DISABLE) ||
566 	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
567 	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
568 	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
569 	    ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO)) {
570 		pr_debug("elantech.c: sending Elantech magic knock failed.\n");
571 		return -1;
572 	}
573 
574 	/*
575 	 * Report this in case there are Elantech models that use a different
576 	 * set of magic numbers
577 	 */
578 	if (param[0] != 0x3c || param[1] != 0x03 || param[2] != 0xc8) {
579 		pr_debug("elantech.c: "
580 			 "unexpected magic knock result 0x%02x, 0x%02x, 0x%02x.\n",
581 			 param[0], param[1], param[2]);
582 		return -1;
583 	}
584 
585 	/*
586 	 * Query touchpad's firmware version and see if it reports known
587 	 * value to avoid mis-detection. Logitech mice are known to respond
588 	 * to Elantech magic knock and there might be more.
589 	 */
590 	if (synaptics_send_cmd(psmouse, ETP_FW_VERSION_QUERY, param)) {
591 		pr_debug("elantech.c: failed to query firmware version.\n");
592 		return -1;
593 	}
594 
595 	pr_debug("elantech.c: Elantech version query result 0x%02x, 0x%02x, 0x%02x.\n",
596 		 param[0], param[1], param[2]);
597 
598 	if (param[0] == 0 || param[1] != 0) {
599 		pr_debug("elantech.c: Probably not a real Elantech touchpad. Aborting.\n");
600 		return -1;
601 	}
602 
603 	if (set_properties) {
604 		psmouse->vendor = "Elantech";
605 		psmouse->name = "Touchpad";
606 	}
607 
608 	return 0;
609 }
610 
611 /*
612  * Clean up sysfs entries when disconnecting
613  */
614 static void elantech_disconnect(struct psmouse *psmouse)
615 {
616 	sysfs_remove_group(&psmouse->ps2dev.serio->dev.kobj,
617 			   &elantech_attr_group);
618 	kfree(psmouse->private);
619 	psmouse->private = NULL;
620 }
621 
622 /*
623  * Put the touchpad back into absolute mode when reconnecting
624  */
625 static int elantech_reconnect(struct psmouse *psmouse)
626 {
627 	if (elantech_detect(psmouse, 0))
628 		return -1;
629 
630 	if (elantech_set_absolute_mode(psmouse)) {
631 		pr_err("elantech.c: failed to put touchpad back into absolute mode.\n");
632 		return -1;
633 	}
634 
635 	return 0;
636 }
637 
638 /*
639  * Initialize the touchpad and create sysfs entries
640  */
641 int elantech_init(struct psmouse *psmouse)
642 {
643 	struct elantech_data *etd;
644 	int i, error;
645 	unsigned char param[3];
646 
647 	psmouse->private = etd = kzalloc(sizeof(struct elantech_data), GFP_KERNEL);
648 	if (!etd)
649 		return -1;
650 
651 	etd->parity[0] = 1;
652 	for (i = 1; i < 256; i++)
653 		etd->parity[i] = etd->parity[i & (i - 1)] ^ 1;
654 
655 	/*
656 	 * Do the version query again so we can store the result
657 	 */
658 	if (synaptics_send_cmd(psmouse, ETP_FW_VERSION_QUERY, param)) {
659 		pr_err("elantech.c: failed to query firmware version.\n");
660 		goto init_fail;
661 	}
662 	etd->fw_version_maj = param[0];
663 	etd->fw_version_min = param[2];
664 
665 	/*
666 	 * Assume every version greater than this is new EeePC style
667 	 * hardware with 6 byte packets
668 	 */
669 	if (etd->fw_version_maj >= 0x02 && etd->fw_version_min >= 0x30) {
670 		etd->hw_version = 2;
671 		/* For now show extra debug information */
672 		etd->debug = 1;
673 		/* Don't know how to do parity checking for version 2 */
674 		etd->paritycheck = 0;
675 	} else {
676 		etd->hw_version = 1;
677 		etd->paritycheck = 1;
678 	}
679 	pr_info("elantech.c: assuming hardware version %d, firmware version %d.%d\n",
680 		etd->hw_version, etd->fw_version_maj, etd->fw_version_min);
681 
682 	if (synaptics_send_cmd(psmouse, ETP_CAPABILITIES_QUERY, param)) {
683 		pr_err("elantech.c: failed to query capabilities.\n");
684 		goto init_fail;
685 	}
686 	pr_info("elantech.c: Synaptics capabilities query result 0x%02x, 0x%02x, 0x%02x.\n",
687 		param[0], param[1], param[2]);
688 	etd->capabilities = param[0];
689 
690 	/*
691 	 * This firmware seems to suffer from misreporting coordinates when
692 	 * a touch action starts causing the mouse cursor or scrolled page
693 	 * to jump. Enable a workaround.
694 	 */
695 	if (etd->fw_version_maj == 0x02 && etd->fw_version_min == 0x22) {
696 		pr_info("elantech.c: firmware version 2.34 detected, "
697 			"enabling jumpy cursor workaround\n");
698 		etd->jumpy_cursor = 1;
699 	}
700 
701 	if (elantech_set_absolute_mode(psmouse)) {
702 		pr_err("elantech.c: failed to put touchpad into absolute mode.\n");
703 		goto init_fail;
704 	}
705 
706 	elantech_set_input_params(psmouse);
707 
708 	error = sysfs_create_group(&psmouse->ps2dev.serio->dev.kobj,
709 				   &elantech_attr_group);
710 	if (error) {
711 		pr_err("elantech.c: failed to create sysfs attributes, error: %d.\n",
712 			error);
713 		goto init_fail;
714 	}
715 
716 	psmouse->protocol_handler = elantech_process_byte;
717 	psmouse->disconnect = elantech_disconnect;
718 	psmouse->reconnect = elantech_reconnect;
719 	psmouse->pktsize = etd->hw_version == 2 ? 6 : 4;
720 
721 	return 0;
722 
723  init_fail:
724 	kfree(etd);
725 	return -1;
726 }
727