xref: /openbmc/linux/drivers/input/mouse/elantech.c (revision b627b4ed)
1 /*
2  * Elantech Touchpad driver (v5)
3  *
4  * Copyright (C) 2007-2008 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/module.h>
15 #include <linux/input.h>
16 #include <linux/serio.h>
17 #include <linux/libps2.h>
18 #include "psmouse.h"
19 #include "elantech.h"
20 
21 #define elantech_debug(format, arg...)				\
22 	do {							\
23 		if (etd->debug)					\
24 			printk(KERN_DEBUG format, ##arg);	\
25 	} while (0)
26 
27 /*
28  * Send a Synaptics style sliced query command
29  */
30 static int synaptics_send_cmd(struct psmouse *psmouse, unsigned char c,
31 				unsigned char *param)
32 {
33 	if (psmouse_sliced_command(psmouse, c) ||
34 	    ps2_command(&psmouse->ps2dev, param, PSMOUSE_CMD_GETINFO)) {
35 		pr_err("elantech.c: synaptics_send_cmd query 0x%02x failed.\n", c);
36 		return -1;
37 	}
38 
39 	return 0;
40 }
41 
42 /*
43  * A retrying version of ps2_command
44  */
45 static int elantech_ps2_command(struct psmouse *psmouse,
46 				unsigned char *param, int command)
47 {
48 	struct ps2dev *ps2dev = &psmouse->ps2dev;
49 	struct elantech_data *etd = psmouse->private;
50 	int rc;
51 	int tries = ETP_PS2_COMMAND_TRIES;
52 
53 	do {
54 		rc = ps2_command(ps2dev, param, command);
55 		if (rc == 0)
56 			break;
57 		tries--;
58 		elantech_debug("elantech.c: retrying ps2 command 0x%02x (%d).\n",
59 			command, tries);
60 		msleep(ETP_PS2_COMMAND_DELAY);
61 	} while (tries > 0);
62 
63 	if (rc)
64 		pr_err("elantech.c: ps2 command 0x%02x failed.\n", command);
65 
66 	return rc;
67 }
68 
69 /*
70  * Send an Elantech style special command to read a value from a register
71  */
72 static int elantech_read_reg(struct psmouse *psmouse, unsigned char reg,
73 				unsigned char *val)
74 {
75 	struct elantech_data *etd = psmouse->private;
76 	unsigned char param[3];
77 	int rc = 0;
78 
79 	if (reg < 0x10 || reg > 0x26)
80 		return -1;
81 
82 	if (reg > 0x11 && reg < 0x20)
83 		return -1;
84 
85 	switch (etd->hw_version) {
86 	case 1:
87 		if (psmouse_sliced_command(psmouse, ETP_REGISTER_READ) ||
88 		    psmouse_sliced_command(psmouse, reg) ||
89 		    ps2_command(&psmouse->ps2dev, param, PSMOUSE_CMD_GETINFO)) {
90 			rc = -1;
91 		}
92 		break;
93 
94 	case 2:
95 		if (elantech_ps2_command(psmouse,  NULL, ETP_PS2_CUSTOM_COMMAND) ||
96 		    elantech_ps2_command(psmouse,  NULL, ETP_REGISTER_READ) ||
97 		    elantech_ps2_command(psmouse,  NULL, ETP_PS2_CUSTOM_COMMAND) ||
98 		    elantech_ps2_command(psmouse,  NULL, reg) ||
99 		    elantech_ps2_command(psmouse, param, PSMOUSE_CMD_GETINFO)) {
100 			rc = -1;
101 		}
102 		break;
103 	}
104 
105 	if (rc)
106 		pr_err("elantech.c: failed to read register 0x%02x.\n", reg);
107 	else
108 		*val = param[0];
109 
110 	return rc;
111 }
112 
113 /*
114  * Send an Elantech style special command to write a register with a value
115  */
116 static int elantech_write_reg(struct psmouse *psmouse, unsigned char reg,
117 				unsigned char val)
118 {
119 	struct elantech_data *etd = psmouse->private;
120 	int rc = 0;
121 
122 	if (reg < 0x10 || reg > 0x26)
123 		return -1;
124 
125 	if (reg > 0x11 && reg < 0x20)
126 		return -1;
127 
128 	switch (etd->hw_version) {
129 	case 1:
130 		if (psmouse_sliced_command(psmouse, ETP_REGISTER_WRITE) ||
131 		    psmouse_sliced_command(psmouse, reg) ||
132 		    psmouse_sliced_command(psmouse, val) ||
133 		    ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_SETSCALE11)) {
134 			rc = -1;
135 		}
136 		break;
137 
138 	case 2:
139 		if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
140 		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_WRITE) ||
141 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
142 		    elantech_ps2_command(psmouse, NULL, reg) ||
143 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
144 		    elantech_ps2_command(psmouse, NULL, val) ||
145 		    elantech_ps2_command(psmouse, NULL, PSMOUSE_CMD_SETSCALE11)) {
146 			rc = -1;
147 		}
148 		break;
149 	}
150 
151 	if (rc)
152 		pr_err("elantech.c: failed to write register 0x%02x with value 0x%02x.\n",
153 			reg, val);
154 
155 	return rc;
156 }
157 
158 /*
159  * Dump a complete mouse movement packet to the syslog
160  */
161 static void elantech_packet_dump(unsigned char *packet, int size)
162 {
163 	int	i;
164 
165 	printk(KERN_DEBUG "elantech.c: PS/2 packet [");
166 	for (i = 0; i < size; i++)
167 		printk("%s0x%02x ", (i) ? ", " : " ", packet[i]);
168 	printk("]\n");
169 }
170 
171 /*
172  * Interpret complete data packets and report absolute mode input events for
173  * hardware version 1. (4 byte packets)
174  */
175 static void elantech_report_absolute_v1(struct psmouse *psmouse)
176 {
177 	struct input_dev *dev = psmouse->dev;
178 	struct elantech_data *etd = psmouse->private;
179 	unsigned char *packet = psmouse->packet;
180 	int fingers;
181 
182 	if (etd->fw_version_maj == 0x01) {
183 		/* byte 0:  D   U  p1  p2   1  p3   R   L
184 		   byte 1:  f   0  th  tw  x9  x8  y9  y8 */
185 		fingers = ((packet[1] & 0x80) >> 7) +
186 				((packet[1] & 0x30) >> 4);
187 	} else {
188 		/* byte 0: n1  n0  p2  p1   1  p3   R   L
189 		   byte 1:  0   0   0   0  x9  x8  y9  y8 */
190 		fingers = (packet[0] & 0xc0) >> 6;
191 	}
192 
193 	input_report_key(dev, BTN_TOUCH, fingers != 0);
194 
195 	/* byte 2: x7  x6  x5  x4  x3  x2  x1  x0
196 	   byte 3: y7  y6  y5  y4  y3  y2  y1  y0 */
197 	if (fingers) {
198 		input_report_abs(dev, ABS_X,
199 			((packet[1] & 0x0c) << 6) | packet[2]);
200 		input_report_abs(dev, ABS_Y, ETP_YMAX_V1 -
201 			(((packet[1] & 0x03) << 8) | packet[3]));
202 	}
203 
204 	input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
205 	input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
206 	input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);
207 	input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
208 	input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);
209 
210 	if ((etd->fw_version_maj == 0x01) &&
211 	    (etd->capabilities & ETP_CAP_HAS_ROCKER)) {
212 		/* rocker up */
213 		input_report_key(dev, BTN_FORWARD, packet[0] & 0x40);
214 		/* rocker down */
215 		input_report_key(dev, BTN_BACK, packet[0] & 0x80);
216 	}
217 
218 	input_sync(dev);
219 }
220 
221 /*
222  * Interpret complete data packets and report absolute mode input events for
223  * hardware version 2. (6 byte packets)
224  */
225 static void elantech_report_absolute_v2(struct psmouse *psmouse)
226 {
227 	struct input_dev *dev = psmouse->dev;
228 	unsigned char *packet = psmouse->packet;
229 	int fingers, x1, y1, x2, y2;
230 
231 	/* byte 0: n1  n0   .   .   .   .   R   L */
232 	fingers = (packet[0] & 0xc0) >> 6;
233 	input_report_key(dev, BTN_TOUCH, fingers != 0);
234 
235 	switch (fingers) {
236 	case 1:
237 		/* byte 1: x15 x14 x13 x12 x11 x10 x9  x8
238 		   byte 2: x7  x6  x5  x4  x4  x2  x1  x0 */
239 		input_report_abs(dev, ABS_X, (packet[1] << 8) | packet[2]);
240 		/* byte 4: y15 y14 y13 y12 y11 y10 y8  y8
241 		   byte 5: y7  y6  y5  y4  y3  y2  y1  y0 */
242 		input_report_abs(dev, ABS_Y, ETP_YMAX_V2 -
243 			((packet[4] << 8) | packet[5]));
244 		break;
245 
246 	case 2:
247 		/* The coordinate of each finger is reported separately with
248 		   a lower resolution for two finger touches */
249 		/* byte 0:  .   .  ay8 ax8  .   .   .   .
250 		   byte 1: ax7 ax6 ax5 ax4 ax3 ax2 ax1 ax0 */
251 		x1 = ((packet[0] & 0x10) << 4) | packet[1];
252 		/* byte 2: ay7 ay6 ay5 ay4 ay3 ay2 ay1 ay0 */
253 		y1 = ETP_2FT_YMAX - (((packet[0] & 0x20) << 3) | packet[2]);
254 		/* byte 3:  .   .  by8 bx8  .   .   .   .
255 		   byte 4: bx7 bx6 bx5 bx4 bx3 bx2 bx1 bx0 */
256 		x2 = ((packet[3] & 0x10) << 4) | packet[4];
257 		/* byte 5: by7 by8 by5 by4 by3 by2 by1 by0 */
258 		y2 = ETP_2FT_YMAX - (((packet[3] & 0x20) << 3) | packet[5]);
259 		/* For compatibility with the X Synaptics driver scale up one
260 		   coordinate and report as ordinary mouse movent */
261 		input_report_abs(dev, ABS_X, x1 << 2);
262 		input_report_abs(dev, ABS_Y, y1 << 2);
263 		/* For compatibility with the proprietary X Elantech driver
264 		   report both coordinates as hat coordinates */
265 		input_report_abs(dev, ABS_HAT0X, x1);
266 		input_report_abs(dev, ABS_HAT0Y, y1);
267 		input_report_abs(dev, ABS_HAT1X, x2);
268 		input_report_abs(dev, ABS_HAT1Y, y2);
269 		break;
270 	}
271 
272 	input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
273 	input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
274 	input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);
275 	input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
276 	input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);
277 
278 	input_sync(dev);
279 }
280 
281 static int elantech_check_parity_v1(struct psmouse *psmouse)
282 {
283 	struct elantech_data *etd = psmouse->private;
284 	unsigned char *packet = psmouse->packet;
285 	unsigned char p1, p2, p3;
286 
287 	/* Parity bits are placed differently */
288 	if (etd->fw_version_maj == 0x01) {
289 		/* byte 0:  D   U  p1  p2   1  p3   R   L */
290 		p1 = (packet[0] & 0x20) >> 5;
291 		p2 = (packet[0] & 0x10) >> 4;
292 	} else {
293 		/* byte 0: n1  n0  p2  p1   1  p3   R   L */
294 		p1 = (packet[0] & 0x10) >> 4;
295 		p2 = (packet[0] & 0x20) >> 5;
296 	}
297 
298 	p3 = (packet[0] & 0x04) >> 2;
299 
300 	return etd->parity[packet[1]] == p1 &&
301 	       etd->parity[packet[2]] == p2 &&
302 	       etd->parity[packet[3]] == p3;
303 }
304 
305 /*
306  * Process byte stream from mouse and handle complete packets
307  */
308 static psmouse_ret_t elantech_process_byte(struct psmouse *psmouse)
309 {
310 	struct elantech_data *etd = psmouse->private;
311 
312 	if (psmouse->pktcnt < psmouse->pktsize)
313 		return PSMOUSE_GOOD_DATA;
314 
315 	if (etd->debug > 1)
316 		elantech_packet_dump(psmouse->packet, psmouse->pktsize);
317 
318 	switch (etd->hw_version) {
319 	case 1:
320 		if (etd->paritycheck && !elantech_check_parity_v1(psmouse))
321 			return PSMOUSE_BAD_DATA;
322 
323 		elantech_report_absolute_v1(psmouse);
324 		break;
325 
326 	case 2:
327 		/* We don't know how to check parity in protocol v2 */
328 		elantech_report_absolute_v2(psmouse);
329 		break;
330 	}
331 
332 	return PSMOUSE_FULL_PACKET;
333 }
334 
335 /*
336  * Put the touchpad into absolute mode
337  */
338 static int elantech_set_absolute_mode(struct psmouse *psmouse)
339 {
340 	struct elantech_data *etd = psmouse->private;
341 	unsigned char val;
342 	int tries = ETP_READ_BACK_TRIES;
343 	int rc = 0;
344 
345 	switch (etd->hw_version) {
346 	case 1:
347 		etd->reg_10 = 0x16;
348 		etd->reg_11 = 0x8f;
349 		if (elantech_write_reg(psmouse, 0x10, etd->reg_10) ||
350 		    elantech_write_reg(psmouse, 0x11, etd->reg_11)) {
351 			rc = -1;
352 		}
353 		break;
354 
355 	case 2:
356 					/* Windows driver values */
357 		etd->reg_10 = 0x54;
358 		etd->reg_11 = 0x88;	/* 0x8a */
359 		etd->reg_21 = 0x60;	/* 0x00 */
360 		if (elantech_write_reg(psmouse, 0x10, etd->reg_10) ||
361 		    elantech_write_reg(psmouse, 0x11, etd->reg_11) ||
362 		    elantech_write_reg(psmouse, 0x21, etd->reg_21)) {
363 			rc = -1;
364 			break;
365 		}
366 		/*
367 		 * Read back reg 0x10. The touchpad is probably initalising
368 		 * and not ready until we read back the value we just wrote.
369 		 */
370 		do {
371 			rc = elantech_read_reg(psmouse, 0x10, &val);
372 			if (rc == 0)
373 				break;
374 			tries--;
375 			elantech_debug("elantech.c: retrying read (%d).\n",
376 				tries);
377 			msleep(ETP_READ_BACK_DELAY);
378 		} while (tries > 0);
379 		if (rc)
380 			pr_err("elantech.c: failed to read back register 0x10.\n");
381 		break;
382 	}
383 
384 	if (rc)
385 		pr_err("elantech.c: failed to initialise registers.\n");
386 
387 	return rc;
388 }
389 
390 /*
391  * Set the appropriate event bits for the input subsystem
392  */
393 static void elantech_set_input_params(struct psmouse *psmouse)
394 {
395 	struct input_dev *dev = psmouse->dev;
396 	struct elantech_data *etd = psmouse->private;
397 
398 	__set_bit(EV_KEY, dev->evbit);
399 	__set_bit(EV_ABS, dev->evbit);
400 
401 	__set_bit(BTN_LEFT, dev->keybit);
402 	__set_bit(BTN_RIGHT, dev->keybit);
403 
404 	__set_bit(BTN_TOUCH, dev->keybit);
405 	__set_bit(BTN_TOOL_FINGER, dev->keybit);
406 	__set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
407 	__set_bit(BTN_TOOL_TRIPLETAP, dev->keybit);
408 
409 	switch (etd->hw_version) {
410 	case 1:
411 		/* Rocker button */
412 		if ((etd->fw_version_maj == 0x01) &&
413 		    (etd->capabilities & ETP_CAP_HAS_ROCKER)) {
414 			__set_bit(BTN_FORWARD, dev->keybit);
415 			__set_bit(BTN_BACK, dev->keybit);
416 		}
417 		input_set_abs_params(dev, ABS_X, ETP_XMIN_V1, ETP_XMAX_V1, 0, 0);
418 		input_set_abs_params(dev, ABS_Y, ETP_YMIN_V1, ETP_YMAX_V1, 0, 0);
419 		break;
420 
421 	case 2:
422 		input_set_abs_params(dev, ABS_X, ETP_XMIN_V2, ETP_XMAX_V2, 0, 0);
423 		input_set_abs_params(dev, ABS_Y, ETP_YMIN_V2, ETP_YMAX_V2, 0, 0);
424 		input_set_abs_params(dev, ABS_HAT0X, ETP_2FT_XMIN, ETP_2FT_XMAX, 0, 0);
425 		input_set_abs_params(dev, ABS_HAT0Y, ETP_2FT_YMIN, ETP_2FT_YMAX, 0, 0);
426 		input_set_abs_params(dev, ABS_HAT1X, ETP_2FT_XMIN, ETP_2FT_XMAX, 0, 0);
427 		input_set_abs_params(dev, ABS_HAT1Y, ETP_2FT_YMIN, ETP_2FT_YMAX, 0, 0);
428 		break;
429 	}
430 }
431 
432 struct elantech_attr_data {
433 	size_t		field_offset;
434 	unsigned char	reg;
435 };
436 
437 /*
438  * Display a register value by reading a sysfs entry
439  */
440 static ssize_t elantech_show_int_attr(struct psmouse *psmouse, void *data,
441 					char *buf)
442 {
443 	struct elantech_data *etd = psmouse->private;
444 	struct elantech_attr_data *attr = data;
445 	unsigned char *reg = (unsigned char *) etd + attr->field_offset;
446 	int rc = 0;
447 
448 	if (attr->reg)
449 		rc = elantech_read_reg(psmouse, attr->reg, reg);
450 
451 	return sprintf(buf, "0x%02x\n", (attr->reg && rc) ? -1 : *reg);
452 }
453 
454 /*
455  * Write a register value by writing a sysfs entry
456  */
457 static ssize_t elantech_set_int_attr(struct psmouse *psmouse,
458 				     void *data, const char *buf, size_t count)
459 {
460 	struct elantech_data *etd = psmouse->private;
461 	struct elantech_attr_data *attr = data;
462 	unsigned char *reg = (unsigned char *) etd + attr->field_offset;
463 	unsigned long value;
464 	int err;
465 
466 	err = strict_strtoul(buf, 16, &value);
467 	if (err)
468 		return err;
469 
470 	if (value > 0xff)
471 		return -EINVAL;
472 
473 	/* Do we need to preserve some bits for version 2 hardware too? */
474 	if (etd->hw_version == 1) {
475 		if (attr->reg == 0x10)
476 			/* Force absolute mode always on */
477 			value |= ETP_R10_ABSOLUTE_MODE;
478 		else if (attr->reg == 0x11)
479 			/* Force 4 byte mode always on */
480 			value |= ETP_R11_4_BYTE_MODE;
481 	}
482 
483 	if (!attr->reg || elantech_write_reg(psmouse, attr->reg, value) == 0)
484 		*reg = value;
485 
486 	return count;
487 }
488 
489 #define ELANTECH_INT_ATTR(_name, _register)				\
490 	static struct elantech_attr_data elantech_attr_##_name = {	\
491 		.field_offset = offsetof(struct elantech_data, _name),	\
492 		.reg = _register,					\
493 	};								\
494 	PSMOUSE_DEFINE_ATTR(_name, S_IWUSR | S_IRUGO,			\
495 			    &elantech_attr_##_name,			\
496 			    elantech_show_int_attr,			\
497 			    elantech_set_int_attr)
498 
499 ELANTECH_INT_ATTR(reg_10, 0x10);
500 ELANTECH_INT_ATTR(reg_11, 0x11);
501 ELANTECH_INT_ATTR(reg_20, 0x20);
502 ELANTECH_INT_ATTR(reg_21, 0x21);
503 ELANTECH_INT_ATTR(reg_22, 0x22);
504 ELANTECH_INT_ATTR(reg_23, 0x23);
505 ELANTECH_INT_ATTR(reg_24, 0x24);
506 ELANTECH_INT_ATTR(reg_25, 0x25);
507 ELANTECH_INT_ATTR(reg_26, 0x26);
508 ELANTECH_INT_ATTR(debug, 0);
509 ELANTECH_INT_ATTR(paritycheck, 0);
510 
511 static struct attribute *elantech_attrs[] = {
512 	&psmouse_attr_reg_10.dattr.attr,
513 	&psmouse_attr_reg_11.dattr.attr,
514 	&psmouse_attr_reg_20.dattr.attr,
515 	&psmouse_attr_reg_21.dattr.attr,
516 	&psmouse_attr_reg_22.dattr.attr,
517 	&psmouse_attr_reg_23.dattr.attr,
518 	&psmouse_attr_reg_24.dattr.attr,
519 	&psmouse_attr_reg_25.dattr.attr,
520 	&psmouse_attr_reg_26.dattr.attr,
521 	&psmouse_attr_debug.dattr.attr,
522 	&psmouse_attr_paritycheck.dattr.attr,
523 	NULL
524 };
525 
526 static struct attribute_group elantech_attr_group = {
527 	.attrs = elantech_attrs,
528 };
529 
530 /*
531  * Use magic knock to detect Elantech touchpad
532  */
533 int elantech_detect(struct psmouse *psmouse, int set_properties)
534 {
535 	struct ps2dev *ps2dev = &psmouse->ps2dev;
536 	unsigned char param[3];
537 
538 	ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_RESET_DIS);
539 
540 	if (ps2_command(ps2dev,  NULL, PSMOUSE_CMD_DISABLE) ||
541 	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
542 	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
543 	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
544 	    ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO)) {
545 		pr_debug("elantech.c: sending Elantech magic knock failed.\n");
546 		return -1;
547 	}
548 
549 	/*
550 	 * Report this in case there are Elantech models that use a different
551 	 * set of magic numbers
552 	 */
553 	if (param[0] != 0x3c || param[1] != 0x03 || param[2] != 0xc8) {
554 		pr_debug("elantech.c: "
555 			 "unexpected magic knock result 0x%02x, 0x%02x, 0x%02x.\n",
556 			 param[0], param[1], param[2]);
557 		return -1;
558 	}
559 
560 	/*
561 	 * Query touchpad's firmware version and see if it reports known
562 	 * value to avoid mis-detection. Logitech mice are known to respond
563 	 * to Elantech magic knock and there might be more.
564 	 */
565 	if (synaptics_send_cmd(psmouse, ETP_FW_VERSION_QUERY, param)) {
566 		pr_debug("elantech.c: failed to query firmware version.\n");
567 		return -1;
568 	}
569 
570 	pr_debug("elantech.c: Elantech version query result 0x%02x, 0x%02x, 0x%02x.\n",
571 		 param[0], param[1], param[2]);
572 
573 	if (param[0] == 0 || param[1] != 0) {
574 		pr_debug("elantech.c: Probably not a real Elantech touchpad. Aborting.\n");
575 		return -1;
576 	}
577 
578 	if (set_properties) {
579 		psmouse->vendor = "Elantech";
580 		psmouse->name = "Touchpad";
581 	}
582 
583 	return 0;
584 }
585 
586 /*
587  * Clean up sysfs entries when disconnecting
588  */
589 static void elantech_disconnect(struct psmouse *psmouse)
590 {
591 	sysfs_remove_group(&psmouse->ps2dev.serio->dev.kobj,
592 			   &elantech_attr_group);
593 	kfree(psmouse->private);
594 	psmouse->private = NULL;
595 }
596 
597 /*
598  * Put the touchpad back into absolute mode when reconnecting
599  */
600 static int elantech_reconnect(struct psmouse *psmouse)
601 {
602 	if (elantech_detect(psmouse, 0))
603 		return -1;
604 
605 	if (elantech_set_absolute_mode(psmouse)) {
606 		pr_err("elantech.c: failed to put touchpad back into absolute mode.\n");
607 		return -1;
608 	}
609 
610 	return 0;
611 }
612 
613 /*
614  * Initialize the touchpad and create sysfs entries
615  */
616 int elantech_init(struct psmouse *psmouse)
617 {
618 	struct elantech_data *etd;
619 	int i, error;
620 	unsigned char param[3];
621 
622 	psmouse->private = etd = kzalloc(sizeof(struct elantech_data), GFP_KERNEL);
623 	if (!etd)
624 		return -1;
625 
626 	etd->parity[0] = 1;
627 	for (i = 1; i < 256; i++)
628 		etd->parity[i] = etd->parity[i & (i - 1)] ^ 1;
629 
630 	/*
631 	 * Do the version query again so we can store the result
632 	 */
633 	if (synaptics_send_cmd(psmouse, ETP_FW_VERSION_QUERY, param)) {
634 		pr_err("elantech.c: failed to query firmware version.\n");
635 		goto init_fail;
636 	}
637 	etd->fw_version_maj = param[0];
638 	etd->fw_version_min = param[2];
639 
640 	/*
641 	 * Assume every version greater than this is new EeePC style
642 	 * hardware with 6 byte packets
643 	 */
644 	if (etd->fw_version_maj >= 0x02 && etd->fw_version_min >= 0x30) {
645 		etd->hw_version = 2;
646 		/* For now show extra debug information */
647 		etd->debug = 1;
648 		/* Don't know how to do parity checking for version 2 */
649 		etd->paritycheck = 0;
650 	} else {
651 		etd->hw_version = 1;
652 		etd->paritycheck = 1;
653 	}
654 	pr_info("elantech.c: assuming hardware version %d, firmware version %d.%d\n",
655 		etd->hw_version, etd->fw_version_maj, etd->fw_version_min);
656 
657 	if (synaptics_send_cmd(psmouse, ETP_CAPABILITIES_QUERY, param)) {
658 		pr_err("elantech.c: failed to query capabilities.\n");
659 		goto init_fail;
660 	}
661 	pr_info("elantech.c: Synaptics capabilities query result 0x%02x, 0x%02x, 0x%02x.\n",
662 		param[0], param[1], param[2]);
663 	etd->capabilities = param[0];
664 
665 	if (elantech_set_absolute_mode(psmouse)) {
666 		pr_err("elantech.c: failed to put touchpad into absolute mode.\n");
667 		goto init_fail;
668 	}
669 
670 	elantech_set_input_params(psmouse);
671 
672 	error = sysfs_create_group(&psmouse->ps2dev.serio->dev.kobj,
673 				   &elantech_attr_group);
674 	if (error) {
675 		pr_err("elantech.c: failed to create sysfs attributes, error: %d.\n",
676 			error);
677 		goto init_fail;
678 	}
679 
680 	psmouse->protocol_handler = elantech_process_byte;
681 	psmouse->disconnect = elantech_disconnect;
682 	psmouse->reconnect = elantech_reconnect;
683 	psmouse->pktsize = etd->hw_version == 2 ? 6 : 4;
684 
685 	return 0;
686 
687  init_fail:
688 	kfree(etd);
689 	return -1;
690 }
691