xref: /linux/drivers/input/mouse/elantech.c (revision 1d421ca9d7edbac1eb118631ee039d50ab54771e)
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/dmi.h>
15 #include <linux/slab.h>
16 #include <linux/module.h>
17 #include <linux/input.h>
18 #include <linux/input/mt.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 			psmouse_printk(KERN_DEBUG, psmouse,		\
28 					fmt, ##__VA_ARGS__);		\
29 	} while (0)
30 
31 /*
32  * Send a Synaptics style sliced query command
33  */
34 static int synaptics_send_cmd(struct psmouse *psmouse, unsigned char c,
35 				unsigned char *param)
36 {
37 	if (psmouse_sliced_command(psmouse, c) ||
38 	    ps2_command(&psmouse->ps2dev, param, PSMOUSE_CMD_GETINFO)) {
39 		psmouse_err(psmouse, "%s query 0x%02x failed.\n", __func__, c);
40 		return -1;
41 	}
42 
43 	return 0;
44 }
45 
46 /*
47  * V3 and later support this fast command
48  */
49 static int elantech_send_cmd(struct psmouse *psmouse, unsigned char c,
50 				unsigned char *param)
51 {
52 	struct ps2dev *ps2dev = &psmouse->ps2dev;
53 
54 	if (ps2_command(ps2dev, NULL, ETP_PS2_CUSTOM_COMMAND) ||
55 	    ps2_command(ps2dev, NULL, c) ||
56 	    ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO)) {
57 		psmouse_err(psmouse, "%s query 0x%02x failed.\n", __func__, c);
58 		return -1;
59 	}
60 
61 	return 0;
62 }
63 
64 /*
65  * A retrying version of ps2_command
66  */
67 static int elantech_ps2_command(struct psmouse *psmouse,
68 				unsigned char *param, int command)
69 {
70 	struct ps2dev *ps2dev = &psmouse->ps2dev;
71 	struct elantech_data *etd = psmouse->private;
72 	int rc;
73 	int tries = ETP_PS2_COMMAND_TRIES;
74 
75 	do {
76 		rc = ps2_command(ps2dev, param, command);
77 		if (rc == 0)
78 			break;
79 		tries--;
80 		elantech_debug("retrying ps2 command 0x%02x (%d).\n",
81 				command, tries);
82 		msleep(ETP_PS2_COMMAND_DELAY);
83 	} while (tries > 0);
84 
85 	if (rc)
86 		psmouse_err(psmouse, "ps2 command 0x%02x failed.\n", command);
87 
88 	return rc;
89 }
90 
91 /*
92  * Send an Elantech style special command to read a value from a register
93  */
94 static int elantech_read_reg(struct psmouse *psmouse, unsigned char reg,
95 				unsigned char *val)
96 {
97 	struct elantech_data *etd = psmouse->private;
98 	unsigned char param[3];
99 	int rc = 0;
100 
101 	if (reg < 0x07 || reg > 0x26)
102 		return -1;
103 
104 	if (reg > 0x11 && reg < 0x20)
105 		return -1;
106 
107 	switch (etd->hw_version) {
108 	case 1:
109 		if (psmouse_sliced_command(psmouse, ETP_REGISTER_READ) ||
110 		    psmouse_sliced_command(psmouse, reg) ||
111 		    ps2_command(&psmouse->ps2dev, param, PSMOUSE_CMD_GETINFO)) {
112 			rc = -1;
113 		}
114 		break;
115 
116 	case 2:
117 		if (elantech_ps2_command(psmouse,  NULL, ETP_PS2_CUSTOM_COMMAND) ||
118 		    elantech_ps2_command(psmouse,  NULL, ETP_REGISTER_READ) ||
119 		    elantech_ps2_command(psmouse,  NULL, ETP_PS2_CUSTOM_COMMAND) ||
120 		    elantech_ps2_command(psmouse,  NULL, reg) ||
121 		    elantech_ps2_command(psmouse, param, PSMOUSE_CMD_GETINFO)) {
122 			rc = -1;
123 		}
124 		break;
125 
126 	case 3 ... 4:
127 		if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
128 		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
129 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
130 		    elantech_ps2_command(psmouse, NULL, reg) ||
131 		    elantech_ps2_command(psmouse, param, PSMOUSE_CMD_GETINFO)) {
132 			rc = -1;
133 		}
134 		break;
135 	}
136 
137 	if (rc)
138 		psmouse_err(psmouse, "failed to read register 0x%02x.\n", reg);
139 	else if (etd->hw_version != 4)
140 		*val = param[0];
141 	else
142 		*val = param[1];
143 
144 	return rc;
145 }
146 
147 /*
148  * Send an Elantech style special command to write a register with a value
149  */
150 static int elantech_write_reg(struct psmouse *psmouse, unsigned char reg,
151 				unsigned char val)
152 {
153 	struct elantech_data *etd = psmouse->private;
154 	int rc = 0;
155 
156 	if (reg < 0x07 || reg > 0x26)
157 		return -1;
158 
159 	if (reg > 0x11 && reg < 0x20)
160 		return -1;
161 
162 	switch (etd->hw_version) {
163 	case 1:
164 		if (psmouse_sliced_command(psmouse, ETP_REGISTER_WRITE) ||
165 		    psmouse_sliced_command(psmouse, reg) ||
166 		    psmouse_sliced_command(psmouse, val) ||
167 		    ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_SETSCALE11)) {
168 			rc = -1;
169 		}
170 		break;
171 
172 	case 2:
173 		if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
174 		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_WRITE) ||
175 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
176 		    elantech_ps2_command(psmouse, NULL, reg) ||
177 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
178 		    elantech_ps2_command(psmouse, NULL, val) ||
179 		    elantech_ps2_command(psmouse, NULL, PSMOUSE_CMD_SETSCALE11)) {
180 			rc = -1;
181 		}
182 		break;
183 
184 	case 3:
185 		if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
186 		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
187 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
188 		    elantech_ps2_command(psmouse, NULL, reg) ||
189 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
190 		    elantech_ps2_command(psmouse, NULL, val) ||
191 		    elantech_ps2_command(psmouse, NULL, PSMOUSE_CMD_SETSCALE11)) {
192 			rc = -1;
193 		}
194 		break;
195 
196 	case 4:
197 		if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
198 		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
199 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
200 		    elantech_ps2_command(psmouse, NULL, reg) ||
201 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
202 		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
203 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
204 		    elantech_ps2_command(psmouse, NULL, val) ||
205 		    elantech_ps2_command(psmouse, NULL, PSMOUSE_CMD_SETSCALE11)) {
206 			rc = -1;
207 		}
208 		break;
209 	}
210 
211 	if (rc)
212 		psmouse_err(psmouse,
213 			    "failed to write register 0x%02x with value 0x%02x.\n",
214 			    reg, val);
215 
216 	return rc;
217 }
218 
219 /*
220  * Dump a complete mouse movement packet to the syslog
221  */
222 static void elantech_packet_dump(struct psmouse *psmouse)
223 {
224 	int	i;
225 
226 	psmouse_printk(KERN_DEBUG, psmouse, "PS/2 packet [");
227 	for (i = 0; i < psmouse->pktsize; i++)
228 		printk("%s0x%02x ", i ? ", " : " ", psmouse->packet[i]);
229 	printk("]\n");
230 }
231 
232 /*
233  * Interpret complete data packets and report absolute mode input events for
234  * hardware version 1. (4 byte packets)
235  */
236 static void elantech_report_absolute_v1(struct psmouse *psmouse)
237 {
238 	struct input_dev *dev = psmouse->dev;
239 	struct elantech_data *etd = psmouse->private;
240 	unsigned char *packet = psmouse->packet;
241 	int fingers;
242 
243 	if (etd->fw_version < 0x020000) {
244 		/*
245 		 * byte 0:  D   U  p1  p2   1  p3   R   L
246 		 * byte 1:  f   0  th  tw  x9  x8  y9  y8
247 		 */
248 		fingers = ((packet[1] & 0x80) >> 7) +
249 				((packet[1] & 0x30) >> 4);
250 	} else {
251 		/*
252 		 * byte 0: n1  n0  p2  p1   1  p3   R   L
253 		 * byte 1:  0   0   0   0  x9  x8  y9  y8
254 		 */
255 		fingers = (packet[0] & 0xc0) >> 6;
256 	}
257 
258 	if (etd->jumpy_cursor) {
259 		if (fingers != 1) {
260 			etd->single_finger_reports = 0;
261 		} else if (etd->single_finger_reports < 2) {
262 			/* Discard first 2 reports of one finger, bogus */
263 			etd->single_finger_reports++;
264 			elantech_debug("discarding packet\n");
265 			return;
266 		}
267 	}
268 
269 	input_report_key(dev, BTN_TOUCH, fingers != 0);
270 
271 	/*
272 	 * byte 2: x7  x6  x5  x4  x3  x2  x1  x0
273 	 * byte 3: y7  y6  y5  y4  y3  y2  y1  y0
274 	 */
275 	if (fingers) {
276 		input_report_abs(dev, ABS_X,
277 			((packet[1] & 0x0c) << 6) | packet[2]);
278 		input_report_abs(dev, ABS_Y,
279 			etd->y_max - (((packet[1] & 0x03) << 8) | packet[3]));
280 	}
281 
282 	input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
283 	input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
284 	input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);
285 	input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
286 	input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);
287 
288 	if (etd->fw_version < 0x020000 &&
289 	    (etd->capabilities[0] & ETP_CAP_HAS_ROCKER)) {
290 		/* rocker up */
291 		input_report_key(dev, BTN_FORWARD, packet[0] & 0x40);
292 		/* rocker down */
293 		input_report_key(dev, BTN_BACK, packet[0] & 0x80);
294 	}
295 
296 	input_sync(dev);
297 }
298 
299 static void elantech_set_slot(struct input_dev *dev, int slot, bool active,
300 			      unsigned int x, unsigned int y)
301 {
302 	input_mt_slot(dev, slot);
303 	input_mt_report_slot_state(dev, MT_TOOL_FINGER, active);
304 	if (active) {
305 		input_report_abs(dev, ABS_MT_POSITION_X, x);
306 		input_report_abs(dev, ABS_MT_POSITION_Y, y);
307 	}
308 }
309 
310 /* x1 < x2 and y1 < y2 when two fingers, x = y = 0 when not pressed */
311 static void elantech_report_semi_mt_data(struct input_dev *dev,
312 					 unsigned int num_fingers,
313 					 unsigned int x1, unsigned int y1,
314 					 unsigned int x2, unsigned int y2)
315 {
316 	elantech_set_slot(dev, 0, num_fingers != 0, x1, y1);
317 	elantech_set_slot(dev, 1, num_fingers == 2, x2, y2);
318 }
319 
320 /*
321  * Interpret complete data packets and report absolute mode input events for
322  * hardware version 2. (6 byte packets)
323  */
324 static void elantech_report_absolute_v2(struct psmouse *psmouse)
325 {
326 	struct elantech_data *etd = psmouse->private;
327 	struct input_dev *dev = psmouse->dev;
328 	unsigned char *packet = psmouse->packet;
329 	unsigned int fingers, x1 = 0, y1 = 0, x2 = 0, y2 = 0;
330 	unsigned int width = 0, pres = 0;
331 
332 	/* byte 0: n1  n0   .   .   .   .   R   L */
333 	fingers = (packet[0] & 0xc0) >> 6;
334 
335 	switch (fingers) {
336 	case 3:
337 		/*
338 		 * Same as one finger, except report of more than 3 fingers:
339 		 * byte 3:  n4  .   w1  w0   .   .   .   .
340 		 */
341 		if (packet[3] & 0x80)
342 			fingers = 4;
343 		/* pass through... */
344 	case 1:
345 		/*
346 		 * byte 1:  .   .   .   .  x11 x10 x9  x8
347 		 * byte 2: x7  x6  x5  x4  x4  x2  x1  x0
348 		 */
349 		x1 = ((packet[1] & 0x0f) << 8) | packet[2];
350 		/*
351 		 * byte 4:  .   .   .   .  y11 y10 y9  y8
352 		 * byte 5: y7  y6  y5  y4  y3  y2  y1  y0
353 		 */
354 		y1 = etd->y_max - (((packet[4] & 0x0f) << 8) | packet[5]);
355 
356 		pres = (packet[1] & 0xf0) | ((packet[4] & 0xf0) >> 4);
357 		width = ((packet[0] & 0x30) >> 2) | ((packet[3] & 0x30) >> 4);
358 		break;
359 
360 	case 2:
361 		/*
362 		 * The coordinate of each finger is reported separately
363 		 * with a lower resolution for two finger touches:
364 		 * byte 0:  .   .  ay8 ax8  .   .   .   .
365 		 * byte 1: ax7 ax6 ax5 ax4 ax3 ax2 ax1 ax0
366 		 */
367 		x1 = (((packet[0] & 0x10) << 4) | packet[1]) << 2;
368 		/* byte 2: ay7 ay6 ay5 ay4 ay3 ay2 ay1 ay0 */
369 		y1 = etd->y_max -
370 			((((packet[0] & 0x20) << 3) | packet[2]) << 2);
371 		/*
372 		 * byte 3:  .   .  by8 bx8  .   .   .   .
373 		 * byte 4: bx7 bx6 bx5 bx4 bx3 bx2 bx1 bx0
374 		 */
375 		x2 = (((packet[3] & 0x10) << 4) | packet[4]) << 2;
376 		/* byte 5: by7 by8 by5 by4 by3 by2 by1 by0 */
377 		y2 = etd->y_max -
378 			((((packet[3] & 0x20) << 3) | packet[5]) << 2);
379 
380 		/* Unknown so just report sensible values */
381 		pres = 127;
382 		width = 7;
383 		break;
384 	}
385 
386 	input_report_key(dev, BTN_TOUCH, fingers != 0);
387 	if (fingers != 0) {
388 		input_report_abs(dev, ABS_X, x1);
389 		input_report_abs(dev, ABS_Y, y1);
390 	}
391 	elantech_report_semi_mt_data(dev, fingers, x1, y1, x2, y2);
392 	input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
393 	input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
394 	input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);
395 	input_report_key(dev, BTN_TOOL_QUADTAP, fingers == 4);
396 	input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
397 	input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);
398 	if (etd->reports_pressure) {
399 		input_report_abs(dev, ABS_PRESSURE, pres);
400 		input_report_abs(dev, ABS_TOOL_WIDTH, width);
401 	}
402 
403 	input_sync(dev);
404 }
405 
406 /*
407  * Interpret complete data packets and report absolute mode input events for
408  * hardware version 3. (12 byte packets for two fingers)
409  */
410 static void elantech_report_absolute_v3(struct psmouse *psmouse,
411 					int packet_type)
412 {
413 	struct input_dev *dev = psmouse->dev;
414 	struct elantech_data *etd = psmouse->private;
415 	unsigned char *packet = psmouse->packet;
416 	unsigned int fingers = 0, x1 = 0, y1 = 0, x2 = 0, y2 = 0;
417 	unsigned int width = 0, pres = 0;
418 
419 	/* byte 0: n1  n0   .   .   .   .   R   L */
420 	fingers = (packet[0] & 0xc0) >> 6;
421 
422 	switch (fingers) {
423 	case 3:
424 	case 1:
425 		/*
426 		 * byte 1:  .   .   .   .  x11 x10 x9  x8
427 		 * byte 2: x7  x6  x5  x4  x4  x2  x1  x0
428 		 */
429 		x1 = ((packet[1] & 0x0f) << 8) | packet[2];
430 		/*
431 		 * byte 4:  .   .   .   .  y11 y10 y9  y8
432 		 * byte 5: y7  y6  y5  y4  y3  y2  y1  y0
433 		 */
434 		y1 = etd->y_max - (((packet[4] & 0x0f) << 8) | packet[5]);
435 		break;
436 
437 	case 2:
438 		if (packet_type == PACKET_V3_HEAD) {
439 			/*
440 			 * byte 1:   .    .    .    .  ax11 ax10 ax9  ax8
441 			 * byte 2: ax7  ax6  ax5  ax4  ax3  ax2  ax1  ax0
442 			 */
443 			etd->mt[0].x = ((packet[1] & 0x0f) << 8) | packet[2];
444 			/*
445 			 * byte 4:   .    .    .    .  ay11 ay10 ay9  ay8
446 			 * byte 5: ay7  ay6  ay5  ay4  ay3  ay2  ay1  ay0
447 			 */
448 			etd->mt[0].y = etd->y_max -
449 				(((packet[4] & 0x0f) << 8) | packet[5]);
450 			/*
451 			 * wait for next packet
452 			 */
453 			return;
454 		}
455 
456 		/* packet_type == PACKET_V3_TAIL */
457 		x1 = etd->mt[0].x;
458 		y1 = etd->mt[0].y;
459 		x2 = ((packet[1] & 0x0f) << 8) | packet[2];
460 		y2 = etd->y_max - (((packet[4] & 0x0f) << 8) | packet[5]);
461 		break;
462 	}
463 
464 	pres = (packet[1] & 0xf0) | ((packet[4] & 0xf0) >> 4);
465 	width = ((packet[0] & 0x30) >> 2) | ((packet[3] & 0x30) >> 4);
466 
467 	input_report_key(dev, BTN_TOUCH, fingers != 0);
468 	if (fingers != 0) {
469 		input_report_abs(dev, ABS_X, x1);
470 		input_report_abs(dev, ABS_Y, y1);
471 	}
472 	elantech_report_semi_mt_data(dev, fingers, x1, y1, x2, y2);
473 	input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
474 	input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
475 	input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);
476 	input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
477 	input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);
478 	input_report_abs(dev, ABS_PRESSURE, pres);
479 	input_report_abs(dev, ABS_TOOL_WIDTH, width);
480 
481 	input_sync(dev);
482 }
483 
484 static void elantech_input_sync_v4(struct psmouse *psmouse)
485 {
486 	struct input_dev *dev = psmouse->dev;
487 	unsigned char *packet = psmouse->packet;
488 
489 	input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
490 	input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);
491 	input_mt_report_pointer_emulation(dev, true);
492 	input_sync(dev);
493 }
494 
495 static void process_packet_status_v4(struct psmouse *psmouse)
496 {
497 	struct input_dev *dev = psmouse->dev;
498 	unsigned char *packet = psmouse->packet;
499 	unsigned fingers;
500 	int i;
501 
502 	/* notify finger state change */
503 	fingers = packet[1] & 0x1f;
504 	for (i = 0; i < ETP_MAX_FINGERS; i++) {
505 		if ((fingers & (1 << i)) == 0) {
506 			input_mt_slot(dev, i);
507 			input_mt_report_slot_state(dev, MT_TOOL_FINGER, false);
508 		}
509 	}
510 
511 	elantech_input_sync_v4(psmouse);
512 }
513 
514 static void process_packet_head_v4(struct psmouse *psmouse)
515 {
516 	struct input_dev *dev = psmouse->dev;
517 	struct elantech_data *etd = psmouse->private;
518 	unsigned char *packet = psmouse->packet;
519 	int id = ((packet[3] & 0xe0) >> 5) - 1;
520 	int pres, traces;
521 
522 	if (id < 0)
523 		return;
524 
525 	etd->mt[id].x = ((packet[1] & 0x0f) << 8) | packet[2];
526 	etd->mt[id].y = etd->y_max - (((packet[4] & 0x0f) << 8) | packet[5]);
527 	pres = (packet[1] & 0xf0) | ((packet[4] & 0xf0) >> 4);
528 	traces = (packet[0] & 0xf0) >> 4;
529 
530 	input_mt_slot(dev, id);
531 	input_mt_report_slot_state(dev, MT_TOOL_FINGER, true);
532 
533 	input_report_abs(dev, ABS_MT_POSITION_X, etd->mt[id].x);
534 	input_report_abs(dev, ABS_MT_POSITION_Y, etd->mt[id].y);
535 	input_report_abs(dev, ABS_MT_PRESSURE, pres);
536 	input_report_abs(dev, ABS_MT_TOUCH_MAJOR, traces * etd->width);
537 	/* report this for backwards compatibility */
538 	input_report_abs(dev, ABS_TOOL_WIDTH, traces);
539 
540 	elantech_input_sync_v4(psmouse);
541 }
542 
543 static void process_packet_motion_v4(struct psmouse *psmouse)
544 {
545 	struct input_dev *dev = psmouse->dev;
546 	struct elantech_data *etd = psmouse->private;
547 	unsigned char *packet = psmouse->packet;
548 	int weight, delta_x1 = 0, delta_y1 = 0, delta_x2 = 0, delta_y2 = 0;
549 	int id, sid;
550 
551 	id = ((packet[0] & 0xe0) >> 5) - 1;
552 	if (id < 0)
553 		return;
554 
555 	sid = ((packet[3] & 0xe0) >> 5) - 1;
556 	weight = (packet[0] & 0x10) ? ETP_WEIGHT_VALUE : 1;
557 	/*
558 	 * Motion packets give us the delta of x, y values of specific fingers,
559 	 * but in two's complement. Let the compiler do the conversion for us.
560 	 * Also _enlarge_ the numbers to int, in case of overflow.
561 	 */
562 	delta_x1 = (signed char)packet[1];
563 	delta_y1 = (signed char)packet[2];
564 	delta_x2 = (signed char)packet[4];
565 	delta_y2 = (signed char)packet[5];
566 
567 	etd->mt[id].x += delta_x1 * weight;
568 	etd->mt[id].y -= delta_y1 * weight;
569 	input_mt_slot(dev, id);
570 	input_report_abs(dev, ABS_MT_POSITION_X, etd->mt[id].x);
571 	input_report_abs(dev, ABS_MT_POSITION_Y, etd->mt[id].y);
572 
573 	if (sid >= 0) {
574 		etd->mt[sid].x += delta_x2 * weight;
575 		etd->mt[sid].y -= delta_y2 * weight;
576 		input_mt_slot(dev, sid);
577 		input_report_abs(dev, ABS_MT_POSITION_X, etd->mt[sid].x);
578 		input_report_abs(dev, ABS_MT_POSITION_Y, etd->mt[sid].y);
579 	}
580 
581 	elantech_input_sync_v4(psmouse);
582 }
583 
584 static void elantech_report_absolute_v4(struct psmouse *psmouse,
585 					int packet_type)
586 {
587 	switch (packet_type) {
588 	case PACKET_V4_STATUS:
589 		process_packet_status_v4(psmouse);
590 		break;
591 
592 	case PACKET_V4_HEAD:
593 		process_packet_head_v4(psmouse);
594 		break;
595 
596 	case PACKET_V4_MOTION:
597 		process_packet_motion_v4(psmouse);
598 		break;
599 
600 	case PACKET_UNKNOWN:
601 	default:
602 		/* impossible to get here */
603 		break;
604 	}
605 }
606 
607 static int elantech_packet_check_v1(struct psmouse *psmouse)
608 {
609 	struct elantech_data *etd = psmouse->private;
610 	unsigned char *packet = psmouse->packet;
611 	unsigned char p1, p2, p3;
612 
613 	/* Parity bits are placed differently */
614 	if (etd->fw_version < 0x020000) {
615 		/* byte 0:  D   U  p1  p2   1  p3   R   L */
616 		p1 = (packet[0] & 0x20) >> 5;
617 		p2 = (packet[0] & 0x10) >> 4;
618 	} else {
619 		/* byte 0: n1  n0  p2  p1   1  p3   R   L */
620 		p1 = (packet[0] & 0x10) >> 4;
621 		p2 = (packet[0] & 0x20) >> 5;
622 	}
623 
624 	p3 = (packet[0] & 0x04) >> 2;
625 
626 	return etd->parity[packet[1]] == p1 &&
627 	       etd->parity[packet[2]] == p2 &&
628 	       etd->parity[packet[3]] == p3;
629 }
630 
631 static int elantech_debounce_check_v2(struct psmouse *psmouse)
632 {
633         /*
634          * When we encounter packet that matches this exactly, it means the
635          * hardware is in debounce status. Just ignore the whole packet.
636          */
637         const u8 debounce_packet[] = { 0x84, 0xff, 0xff, 0x02, 0xff, 0xff };
638         unsigned char *packet = psmouse->packet;
639 
640         return !memcmp(packet, debounce_packet, sizeof(debounce_packet));
641 }
642 
643 static int elantech_packet_check_v2(struct psmouse *psmouse)
644 {
645 	struct elantech_data *etd = psmouse->private;
646 	unsigned char *packet = psmouse->packet;
647 
648 	/*
649 	 * V2 hardware has two flavors. Older ones that do not report pressure,
650 	 * and newer ones that reports pressure and width. With newer ones, all
651 	 * packets (1, 2, 3 finger touch) have the same constant bits. With
652 	 * older ones, 1/3 finger touch packets and 2 finger touch packets
653 	 * have different constant bits.
654 	 * With all three cases, if the constant bits are not exactly what I
655 	 * expected, I consider them invalid.
656 	 */
657 	if (etd->reports_pressure)
658 		return (packet[0] & 0x0c) == 0x04 &&
659 		       (packet[3] & 0x0f) == 0x02;
660 
661 	if ((packet[0] & 0xc0) == 0x80)
662 		return (packet[0] & 0x0c) == 0x0c &&
663 		       (packet[3] & 0x0e) == 0x08;
664 
665 	return (packet[0] & 0x3c) == 0x3c &&
666 	       (packet[1] & 0xf0) == 0x00 &&
667 	       (packet[3] & 0x3e) == 0x38 &&
668 	       (packet[4] & 0xf0) == 0x00;
669 }
670 
671 /*
672  * We check the constant bits to determine what packet type we get,
673  * so packet checking is mandatory for v3 and later hardware.
674  */
675 static int elantech_packet_check_v3(struct psmouse *psmouse)
676 {
677 	struct elantech_data *etd = psmouse->private;
678 	const u8 debounce_packet[] = { 0xc4, 0xff, 0xff, 0x02, 0xff, 0xff };
679 	unsigned char *packet = psmouse->packet;
680 
681 	/*
682 	 * check debounce first, it has the same signature in byte 0
683 	 * and byte 3 as PACKET_V3_HEAD.
684 	 */
685 	if (!memcmp(packet, debounce_packet, sizeof(debounce_packet)))
686 		return PACKET_DEBOUNCE;
687 
688 	/*
689 	 * If the hardware flag 'crc_enabled' is set the packets have
690 	 * different signatures.
691 	 */
692 	if (etd->crc_enabled) {
693 		if ((packet[3] & 0x09) == 0x08)
694 			return PACKET_V3_HEAD;
695 
696 		if ((packet[3] & 0x09) == 0x09)
697 			return PACKET_V3_TAIL;
698 	} else {
699 		if ((packet[0] & 0x0c) == 0x04 && (packet[3] & 0xcf) == 0x02)
700 			return PACKET_V3_HEAD;
701 
702 		if ((packet[0] & 0x0c) == 0x0c && (packet[3] & 0xce) == 0x0c)
703 			return PACKET_V3_TAIL;
704 	}
705 
706 	return PACKET_UNKNOWN;
707 }
708 
709 static int elantech_packet_check_v4(struct psmouse *psmouse)
710 {
711 	struct elantech_data *etd = psmouse->private;
712 	unsigned char *packet = psmouse->packet;
713 	unsigned char packet_type = packet[3] & 0x03;
714 	bool sanity_check;
715 
716 	/*
717 	 * Sanity check based on the constant bits of a packet.
718 	 * The constant bits change depending on the value of
719 	 * the hardware flag 'crc_enabled' but are the same for
720 	 * every packet, regardless of the type.
721 	 */
722 	if (etd->crc_enabled)
723 		sanity_check = ((packet[3] & 0x08) == 0x00);
724 	else
725 		sanity_check = ((packet[0] & 0x0c) == 0x04 &&
726 				(packet[3] & 0x1c) == 0x10);
727 
728 	if (!sanity_check)
729 		return PACKET_UNKNOWN;
730 
731 	switch (packet_type) {
732 	case 0:
733 		return PACKET_V4_STATUS;
734 
735 	case 1:
736 		return PACKET_V4_HEAD;
737 
738 	case 2:
739 		return PACKET_V4_MOTION;
740 	}
741 
742 	return PACKET_UNKNOWN;
743 }
744 
745 /*
746  * Process byte stream from mouse and handle complete packets
747  */
748 static psmouse_ret_t elantech_process_byte(struct psmouse *psmouse)
749 {
750 	struct elantech_data *etd = psmouse->private;
751 	int packet_type;
752 
753 	if (psmouse->pktcnt < psmouse->pktsize)
754 		return PSMOUSE_GOOD_DATA;
755 
756 	if (etd->debug > 1)
757 		elantech_packet_dump(psmouse);
758 
759 	switch (etd->hw_version) {
760 	case 1:
761 		if (etd->paritycheck && !elantech_packet_check_v1(psmouse))
762 			return PSMOUSE_BAD_DATA;
763 
764 		elantech_report_absolute_v1(psmouse);
765 		break;
766 
767 	case 2:
768 		/* ignore debounce */
769 		if (elantech_debounce_check_v2(psmouse))
770 			return PSMOUSE_FULL_PACKET;
771 
772 		if (etd->paritycheck && !elantech_packet_check_v2(psmouse))
773 			return PSMOUSE_BAD_DATA;
774 
775 		elantech_report_absolute_v2(psmouse);
776 		break;
777 
778 	case 3:
779 		packet_type = elantech_packet_check_v3(psmouse);
780 		/* ignore debounce */
781 		if (packet_type == PACKET_DEBOUNCE)
782 			return PSMOUSE_FULL_PACKET;
783 
784 		if (packet_type == PACKET_UNKNOWN)
785 			return PSMOUSE_BAD_DATA;
786 
787 		elantech_report_absolute_v3(psmouse, packet_type);
788 		break;
789 
790 	case 4:
791 		packet_type = elantech_packet_check_v4(psmouse);
792 		if (packet_type == PACKET_UNKNOWN)
793 			return PSMOUSE_BAD_DATA;
794 
795 		elantech_report_absolute_v4(psmouse, packet_type);
796 		break;
797 	}
798 
799 	return PSMOUSE_FULL_PACKET;
800 }
801 
802 /*
803  * Put the touchpad into absolute mode
804  */
805 static int elantech_set_absolute_mode(struct psmouse *psmouse)
806 {
807 	struct elantech_data *etd = psmouse->private;
808 	unsigned char val;
809 	int tries = ETP_READ_BACK_TRIES;
810 	int rc = 0;
811 
812 	switch (etd->hw_version) {
813 	case 1:
814 		etd->reg_10 = 0x16;
815 		etd->reg_11 = 0x8f;
816 		if (elantech_write_reg(psmouse, 0x10, etd->reg_10) ||
817 		    elantech_write_reg(psmouse, 0x11, etd->reg_11)) {
818 			rc = -1;
819 		}
820 		break;
821 
822 	case 2:
823 					/* Windows driver values */
824 		etd->reg_10 = 0x54;
825 		etd->reg_11 = 0x88;	/* 0x8a */
826 		etd->reg_21 = 0x60;	/* 0x00 */
827 		if (elantech_write_reg(psmouse, 0x10, etd->reg_10) ||
828 		    elantech_write_reg(psmouse, 0x11, etd->reg_11) ||
829 		    elantech_write_reg(psmouse, 0x21, etd->reg_21)) {
830 			rc = -1;
831 		}
832 		break;
833 
834 	case 3:
835 		if (etd->set_hw_resolution)
836 			etd->reg_10 = 0x0b;
837 		else
838 			etd->reg_10 = 0x03;
839 
840 		if (elantech_write_reg(psmouse, 0x10, etd->reg_10))
841 			rc = -1;
842 
843 		break;
844 
845 	case 4:
846 		etd->reg_07 = 0x01;
847 		if (elantech_write_reg(psmouse, 0x07, etd->reg_07))
848 			rc = -1;
849 
850 		goto skip_readback_reg_10; /* v4 has no reg 0x10 to read */
851 	}
852 
853 	if (rc == 0) {
854 		/*
855 		 * Read back reg 0x10. For hardware version 1 we must make
856 		 * sure the absolute mode bit is set. For hardware version 2
857 		 * the touchpad is probably initializing and not ready until
858 		 * we read back the value we just wrote.
859 		 */
860 		do {
861 			rc = elantech_read_reg(psmouse, 0x10, &val);
862 			if (rc == 0)
863 				break;
864 			tries--;
865 			elantech_debug("retrying read (%d).\n", tries);
866 			msleep(ETP_READ_BACK_DELAY);
867 		} while (tries > 0);
868 
869 		if (rc) {
870 			psmouse_err(psmouse,
871 				    "failed to read back register 0x10.\n");
872 		} else if (etd->hw_version == 1 &&
873 			   !(val & ETP_R10_ABSOLUTE_MODE)) {
874 			psmouse_err(psmouse,
875 				    "touchpad refuses to switch to absolute mode.\n");
876 			rc = -1;
877 		}
878 	}
879 
880  skip_readback_reg_10:
881 	if (rc)
882 		psmouse_err(psmouse, "failed to initialise registers.\n");
883 
884 	return rc;
885 }
886 
887 static int elantech_set_range(struct psmouse *psmouse,
888 			      unsigned int *x_min, unsigned int *y_min,
889 			      unsigned int *x_max, unsigned int *y_max,
890 			      unsigned int *width)
891 {
892 	struct elantech_data *etd = psmouse->private;
893 	unsigned char param[3];
894 	unsigned char traces;
895 
896 	switch (etd->hw_version) {
897 	case 1:
898 		*x_min = ETP_XMIN_V1;
899 		*y_min = ETP_YMIN_V1;
900 		*x_max = ETP_XMAX_V1;
901 		*y_max = ETP_YMAX_V1;
902 		break;
903 
904 	case 2:
905 		if (etd->fw_version == 0x020800 ||
906 		    etd->fw_version == 0x020b00 ||
907 		    etd->fw_version == 0x020030) {
908 			*x_min = ETP_XMIN_V2;
909 			*y_min = ETP_YMIN_V2;
910 			*x_max = ETP_XMAX_V2;
911 			*y_max = ETP_YMAX_V2;
912 		} else {
913 			int i;
914 			int fixed_dpi;
915 
916 			i = (etd->fw_version > 0x020800 &&
917 			     etd->fw_version < 0x020900) ? 1 : 2;
918 
919 			if (etd->send_cmd(psmouse, ETP_FW_ID_QUERY, param))
920 				return -1;
921 
922 			fixed_dpi = param[1] & 0x10;
923 
924 			if (((etd->fw_version >> 16) == 0x14) && fixed_dpi) {
925 				if (etd->send_cmd(psmouse, ETP_SAMPLE_QUERY, param))
926 					return -1;
927 
928 				*x_max = (etd->capabilities[1] - i) * param[1] / 2;
929 				*y_max = (etd->capabilities[2] - i) * param[2] / 2;
930 			} else if (etd->fw_version == 0x040216) {
931 				*x_max = 819;
932 				*y_max = 405;
933 			} else if (etd->fw_version == 0x040219 || etd->fw_version == 0x040215) {
934 				*x_max = 900;
935 				*y_max = 500;
936 			} else {
937 				*x_max = (etd->capabilities[1] - i) * 64;
938 				*y_max = (etd->capabilities[2] - i) * 64;
939 			}
940 		}
941 		break;
942 
943 	case 3:
944 		if (etd->send_cmd(psmouse, ETP_FW_ID_QUERY, param))
945 			return -1;
946 
947 		*x_max = (0x0f & param[0]) << 8 | param[1];
948 		*y_max = (0xf0 & param[0]) << 4 | param[2];
949 		break;
950 
951 	case 4:
952 		if (etd->send_cmd(psmouse, ETP_FW_ID_QUERY, param))
953 			return -1;
954 
955 		*x_max = (0x0f & param[0]) << 8 | param[1];
956 		*y_max = (0xf0 & param[0]) << 4 | param[2];
957 		traces = etd->capabilities[1];
958 		if ((traces < 2) || (traces > *x_max))
959 			return -1;
960 
961 		*width = *x_max / (traces - 1);
962 		break;
963 	}
964 
965 	return 0;
966 }
967 
968 /*
969  * (value from firmware) * 10 + 790 = dpi
970  * we also have to convert dpi to dots/mm (*10/254 to avoid floating point)
971  */
972 static unsigned int elantech_convert_res(unsigned int val)
973 {
974 	return (val * 10 + 790) * 10 / 254;
975 }
976 
977 static int elantech_get_resolution_v4(struct psmouse *psmouse,
978 				      unsigned int *x_res,
979 				      unsigned int *y_res)
980 {
981 	unsigned char param[3];
982 
983 	if (elantech_send_cmd(psmouse, ETP_RESOLUTION_QUERY, param))
984 		return -1;
985 
986 	*x_res = elantech_convert_res(param[1] & 0x0f);
987 	*y_res = elantech_convert_res((param[1] & 0xf0) >> 4);
988 
989 	return 0;
990 }
991 
992 /*
993  * Advertise INPUT_PROP_BUTTONPAD for clickpads. The testing of bit 12 in
994  * fw_version for this is based on the following fw_version & caps table:
995  *
996  * Laptop-model:           fw_version:     caps:           buttons:
997  * Acer S3                 0x461f00        10, 13, 0e      clickpad
998  * Acer S7-392             0x581f01        50, 17, 0d      clickpad
999  * Acer V5-131             0x461f02        01, 16, 0c      clickpad
1000  * Acer V5-551             0x461f00        ?               clickpad
1001  * Asus K53SV              0x450f01        78, 15, 0c      2 hw buttons
1002  * Asus G46VW              0x460f02        00, 18, 0c      2 hw buttons
1003  * Asus G750JX             0x360f00        00, 16, 0c      2 hw buttons
1004  * Asus UX31               0x361f00        20, 15, 0e      clickpad
1005  * Asus UX32VD             0x361f02        00, 15, 0e      clickpad
1006  * Avatar AVIU-145A2       0x361f00        ?               clickpad
1007  * Gigabyte U2442          0x450f01        58, 17, 0c      2 hw buttons
1008  * Lenovo L430             0x350f02        b9, 15, 0c      2 hw buttons (*)
1009  * Samsung NF210           0x150b00        78, 14, 0a      2 hw buttons
1010  * Samsung NP770Z5E        0x575f01        10, 15, 0f      clickpad
1011  * Samsung NP700Z5B        0x361f06        21, 15, 0f      clickpad
1012  * Samsung NP900X3E-A02    0x575f03        ?               clickpad
1013  * Samsung NP-QX410        0x851b00        19, 14, 0c      clickpad
1014  * Samsung RC512           0x450f00        08, 15, 0c      2 hw buttons
1015  * Samsung RF710           0x450f00        ?               2 hw buttons
1016  * System76 Pangolin       0x250f01        ?               2 hw buttons
1017  * (*) + 3 trackpoint buttons
1018  */
1019 static void elantech_set_buttonpad_prop(struct psmouse *psmouse)
1020 {
1021 	struct input_dev *dev = psmouse->dev;
1022 	struct elantech_data *etd = psmouse->private;
1023 
1024 	if (etd->fw_version & 0x001000) {
1025 		__set_bit(INPUT_PROP_BUTTONPAD, dev->propbit);
1026 		__clear_bit(BTN_RIGHT, dev->keybit);
1027 	}
1028 }
1029 
1030 /*
1031  * Set the appropriate event bits for the input subsystem
1032  */
1033 static int elantech_set_input_params(struct psmouse *psmouse)
1034 {
1035 	struct input_dev *dev = psmouse->dev;
1036 	struct elantech_data *etd = psmouse->private;
1037 	unsigned int x_min = 0, y_min = 0, x_max = 0, y_max = 0, width = 0;
1038 	unsigned int x_res = 0, y_res = 0;
1039 
1040 	if (elantech_set_range(psmouse, &x_min, &y_min, &x_max, &y_max, &width))
1041 		return -1;
1042 
1043 	__set_bit(INPUT_PROP_POINTER, dev->propbit);
1044 	__set_bit(EV_KEY, dev->evbit);
1045 	__set_bit(EV_ABS, dev->evbit);
1046 	__clear_bit(EV_REL, dev->evbit);
1047 
1048 	__set_bit(BTN_LEFT, dev->keybit);
1049 	__set_bit(BTN_RIGHT, dev->keybit);
1050 
1051 	__set_bit(BTN_TOUCH, dev->keybit);
1052 	__set_bit(BTN_TOOL_FINGER, dev->keybit);
1053 	__set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
1054 	__set_bit(BTN_TOOL_TRIPLETAP, dev->keybit);
1055 
1056 	switch (etd->hw_version) {
1057 	case 1:
1058 		/* Rocker button */
1059 		if (etd->fw_version < 0x020000 &&
1060 		    (etd->capabilities[0] & ETP_CAP_HAS_ROCKER)) {
1061 			__set_bit(BTN_FORWARD, dev->keybit);
1062 			__set_bit(BTN_BACK, dev->keybit);
1063 		}
1064 		input_set_abs_params(dev, ABS_X, x_min, x_max, 0, 0);
1065 		input_set_abs_params(dev, ABS_Y, y_min, y_max, 0, 0);
1066 		break;
1067 
1068 	case 2:
1069 		__set_bit(BTN_TOOL_QUADTAP, dev->keybit);
1070 		__set_bit(INPUT_PROP_SEMI_MT, dev->propbit);
1071 		/* fall through */
1072 	case 3:
1073 		if (etd->hw_version == 3)
1074 			elantech_set_buttonpad_prop(psmouse);
1075 		input_set_abs_params(dev, ABS_X, x_min, x_max, 0, 0);
1076 		input_set_abs_params(dev, ABS_Y, y_min, y_max, 0, 0);
1077 		if (etd->reports_pressure) {
1078 			input_set_abs_params(dev, ABS_PRESSURE, ETP_PMIN_V2,
1079 					     ETP_PMAX_V2, 0, 0);
1080 			input_set_abs_params(dev, ABS_TOOL_WIDTH, ETP_WMIN_V2,
1081 					     ETP_WMAX_V2, 0, 0);
1082 		}
1083 		input_mt_init_slots(dev, 2, 0);
1084 		input_set_abs_params(dev, ABS_MT_POSITION_X, x_min, x_max, 0, 0);
1085 		input_set_abs_params(dev, ABS_MT_POSITION_Y, y_min, y_max, 0, 0);
1086 		break;
1087 
1088 	case 4:
1089 		if (elantech_get_resolution_v4(psmouse, &x_res, &y_res)) {
1090 			/*
1091 			 * if query failed, print a warning and leave the values
1092 			 * zero to resemble synaptics.c behavior.
1093 			 */
1094 			psmouse_warn(psmouse, "couldn't query resolution data.\n");
1095 		}
1096 		elantech_set_buttonpad_prop(psmouse);
1097 		__set_bit(BTN_TOOL_QUADTAP, dev->keybit);
1098 		/* For X to recognize me as touchpad. */
1099 		input_set_abs_params(dev, ABS_X, x_min, x_max, 0, 0);
1100 		input_set_abs_params(dev, ABS_Y, y_min, y_max, 0, 0);
1101 		input_abs_set_res(dev, ABS_X, x_res);
1102 		input_abs_set_res(dev, ABS_Y, y_res);
1103 		/*
1104 		 * range of pressure and width is the same as v2,
1105 		 * report ABS_PRESSURE, ABS_TOOL_WIDTH for compatibility.
1106 		 */
1107 		input_set_abs_params(dev, ABS_PRESSURE, ETP_PMIN_V2,
1108 				     ETP_PMAX_V2, 0, 0);
1109 		input_set_abs_params(dev, ABS_TOOL_WIDTH, ETP_WMIN_V2,
1110 				     ETP_WMAX_V2, 0, 0);
1111 		/* Multitouch capable pad, up to 5 fingers. */
1112 		input_mt_init_slots(dev, ETP_MAX_FINGERS, 0);
1113 		input_set_abs_params(dev, ABS_MT_POSITION_X, x_min, x_max, 0, 0);
1114 		input_set_abs_params(dev, ABS_MT_POSITION_Y, y_min, y_max, 0, 0);
1115 		input_abs_set_res(dev, ABS_MT_POSITION_X, x_res);
1116 		input_abs_set_res(dev, ABS_MT_POSITION_Y, y_res);
1117 		input_set_abs_params(dev, ABS_MT_PRESSURE, ETP_PMIN_V2,
1118 				     ETP_PMAX_V2, 0, 0);
1119 		/*
1120 		 * The firmware reports how many trace lines the finger spans,
1121 		 * convert to surface unit as Protocol-B requires.
1122 		 */
1123 		input_set_abs_params(dev, ABS_MT_TOUCH_MAJOR, 0,
1124 				     ETP_WMAX_V2 * width, 0, 0);
1125 		break;
1126 	}
1127 
1128 	etd->y_max = y_max;
1129 	etd->width = width;
1130 
1131 	return 0;
1132 }
1133 
1134 struct elantech_attr_data {
1135 	size_t		field_offset;
1136 	unsigned char	reg;
1137 };
1138 
1139 /*
1140  * Display a register value by reading a sysfs entry
1141  */
1142 static ssize_t elantech_show_int_attr(struct psmouse *psmouse, void *data,
1143 					char *buf)
1144 {
1145 	struct elantech_data *etd = psmouse->private;
1146 	struct elantech_attr_data *attr = data;
1147 	unsigned char *reg = (unsigned char *) etd + attr->field_offset;
1148 	int rc = 0;
1149 
1150 	if (attr->reg)
1151 		rc = elantech_read_reg(psmouse, attr->reg, reg);
1152 
1153 	return sprintf(buf, "0x%02x\n", (attr->reg && rc) ? -1 : *reg);
1154 }
1155 
1156 /*
1157  * Write a register value by writing a sysfs entry
1158  */
1159 static ssize_t elantech_set_int_attr(struct psmouse *psmouse,
1160 				     void *data, const char *buf, size_t count)
1161 {
1162 	struct elantech_data *etd = psmouse->private;
1163 	struct elantech_attr_data *attr = data;
1164 	unsigned char *reg = (unsigned char *) etd + attr->field_offset;
1165 	unsigned char value;
1166 	int err;
1167 
1168 	err = kstrtou8(buf, 16, &value);
1169 	if (err)
1170 		return err;
1171 
1172 	/* Do we need to preserve some bits for version 2 hardware too? */
1173 	if (etd->hw_version == 1) {
1174 		if (attr->reg == 0x10)
1175 			/* Force absolute mode always on */
1176 			value |= ETP_R10_ABSOLUTE_MODE;
1177 		else if (attr->reg == 0x11)
1178 			/* Force 4 byte mode always on */
1179 			value |= ETP_R11_4_BYTE_MODE;
1180 	}
1181 
1182 	if (!attr->reg || elantech_write_reg(psmouse, attr->reg, value) == 0)
1183 		*reg = value;
1184 
1185 	return count;
1186 }
1187 
1188 #define ELANTECH_INT_ATTR(_name, _register)				\
1189 	static struct elantech_attr_data elantech_attr_##_name = {	\
1190 		.field_offset = offsetof(struct elantech_data, _name),	\
1191 		.reg = _register,					\
1192 	};								\
1193 	PSMOUSE_DEFINE_ATTR(_name, S_IWUSR | S_IRUGO,			\
1194 			    &elantech_attr_##_name,			\
1195 			    elantech_show_int_attr,			\
1196 			    elantech_set_int_attr)
1197 
1198 ELANTECH_INT_ATTR(reg_07, 0x07);
1199 ELANTECH_INT_ATTR(reg_10, 0x10);
1200 ELANTECH_INT_ATTR(reg_11, 0x11);
1201 ELANTECH_INT_ATTR(reg_20, 0x20);
1202 ELANTECH_INT_ATTR(reg_21, 0x21);
1203 ELANTECH_INT_ATTR(reg_22, 0x22);
1204 ELANTECH_INT_ATTR(reg_23, 0x23);
1205 ELANTECH_INT_ATTR(reg_24, 0x24);
1206 ELANTECH_INT_ATTR(reg_25, 0x25);
1207 ELANTECH_INT_ATTR(reg_26, 0x26);
1208 ELANTECH_INT_ATTR(debug, 0);
1209 ELANTECH_INT_ATTR(paritycheck, 0);
1210 
1211 static struct attribute *elantech_attrs[] = {
1212 	&psmouse_attr_reg_07.dattr.attr,
1213 	&psmouse_attr_reg_10.dattr.attr,
1214 	&psmouse_attr_reg_11.dattr.attr,
1215 	&psmouse_attr_reg_20.dattr.attr,
1216 	&psmouse_attr_reg_21.dattr.attr,
1217 	&psmouse_attr_reg_22.dattr.attr,
1218 	&psmouse_attr_reg_23.dattr.attr,
1219 	&psmouse_attr_reg_24.dattr.attr,
1220 	&psmouse_attr_reg_25.dattr.attr,
1221 	&psmouse_attr_reg_26.dattr.attr,
1222 	&psmouse_attr_debug.dattr.attr,
1223 	&psmouse_attr_paritycheck.dattr.attr,
1224 	NULL
1225 };
1226 
1227 static struct attribute_group elantech_attr_group = {
1228 	.attrs = elantech_attrs,
1229 };
1230 
1231 static bool elantech_is_signature_valid(const unsigned char *param)
1232 {
1233 	static const unsigned char rates[] = { 200, 100, 80, 60, 40, 20, 10 };
1234 	int i;
1235 
1236 	if (param[0] == 0)
1237 		return false;
1238 
1239 	if (param[1] == 0)
1240 		return true;
1241 
1242 	for (i = 0; i < ARRAY_SIZE(rates); i++)
1243 		if (param[2] == rates[i])
1244 			return false;
1245 
1246 	return true;
1247 }
1248 
1249 /*
1250  * Use magic knock to detect Elantech touchpad
1251  */
1252 int elantech_detect(struct psmouse *psmouse, bool set_properties)
1253 {
1254 	struct ps2dev *ps2dev = &psmouse->ps2dev;
1255 	unsigned char param[3];
1256 
1257 	ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_RESET_DIS);
1258 
1259 	if (ps2_command(ps2dev,  NULL, PSMOUSE_CMD_DISABLE) ||
1260 	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
1261 	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
1262 	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
1263 	    ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO)) {
1264 		psmouse_dbg(psmouse, "sending Elantech magic knock failed.\n");
1265 		return -1;
1266 	}
1267 
1268 	/*
1269 	 * Report this in case there are Elantech models that use a different
1270 	 * set of magic numbers
1271 	 */
1272 	if (param[0] != 0x3c || param[1] != 0x03 ||
1273 	    (param[2] != 0xc8 && param[2] != 0x00)) {
1274 		psmouse_dbg(psmouse,
1275 			    "unexpected magic knock result 0x%02x, 0x%02x, 0x%02x.\n",
1276 			    param[0], param[1], param[2]);
1277 		return -1;
1278 	}
1279 
1280 	/*
1281 	 * Query touchpad's firmware version and see if it reports known
1282 	 * value to avoid mis-detection. Logitech mice are known to respond
1283 	 * to Elantech magic knock and there might be more.
1284 	 */
1285 	if (synaptics_send_cmd(psmouse, ETP_FW_VERSION_QUERY, param)) {
1286 		psmouse_dbg(psmouse, "failed to query firmware version.\n");
1287 		return -1;
1288 	}
1289 
1290 	psmouse_dbg(psmouse,
1291 		    "Elantech version query result 0x%02x, 0x%02x, 0x%02x.\n",
1292 		    param[0], param[1], param[2]);
1293 
1294 	if (!elantech_is_signature_valid(param)) {
1295 		psmouse_dbg(psmouse,
1296 			    "Probably not a real Elantech touchpad. Aborting.\n");
1297 		return -1;
1298 	}
1299 
1300 	if (set_properties) {
1301 		psmouse->vendor = "Elantech";
1302 		psmouse->name = "Touchpad";
1303 	}
1304 
1305 	return 0;
1306 }
1307 
1308 /*
1309  * Clean up sysfs entries when disconnecting
1310  */
1311 static void elantech_disconnect(struct psmouse *psmouse)
1312 {
1313 	sysfs_remove_group(&psmouse->ps2dev.serio->dev.kobj,
1314 			   &elantech_attr_group);
1315 	kfree(psmouse->private);
1316 	psmouse->private = NULL;
1317 }
1318 
1319 /*
1320  * Put the touchpad back into absolute mode when reconnecting
1321  */
1322 static int elantech_reconnect(struct psmouse *psmouse)
1323 {
1324 	psmouse_reset(psmouse);
1325 
1326 	if (elantech_detect(psmouse, 0))
1327 		return -1;
1328 
1329 	if (elantech_set_absolute_mode(psmouse)) {
1330 		psmouse_err(psmouse,
1331 			    "failed to put touchpad back into absolute mode.\n");
1332 		return -1;
1333 	}
1334 
1335 	return 0;
1336 }
1337 
1338 /*
1339  * Some hw_version 3 models go into error state when we try to set bit 3 of r10
1340  */
1341 static const struct dmi_system_id no_hw_res_dmi_table[] = {
1342 #if defined(CONFIG_DMI) && defined(CONFIG_X86)
1343 	{
1344 		/* Gigabyte U2442 */
1345 		.matches = {
1346 			DMI_MATCH(DMI_SYS_VENDOR, "GIGABYTE"),
1347 			DMI_MATCH(DMI_PRODUCT_NAME, "U2442"),
1348 		},
1349 	},
1350 #endif
1351 	{ }
1352 };
1353 
1354 /*
1355  * determine hardware version and set some properties according to it.
1356  */
1357 static int elantech_set_properties(struct elantech_data *etd)
1358 {
1359 	/* This represents the version of IC body. */
1360 	int ver = (etd->fw_version & 0x0f0000) >> 16;
1361 
1362 	/* Early version of Elan touchpads doesn't obey the rule. */
1363 	if (etd->fw_version < 0x020030 || etd->fw_version == 0x020600)
1364 		etd->hw_version = 1;
1365 	else {
1366 		switch (ver) {
1367 		case 2:
1368 		case 4:
1369 			etd->hw_version = 2;
1370 			break;
1371 		case 5:
1372 			etd->hw_version = 3;
1373 			break;
1374 		case 6:
1375 		case 7:
1376 		case 8:
1377 		case 9:
1378 			etd->hw_version = 4;
1379 			break;
1380 		default:
1381 			return -1;
1382 		}
1383 	}
1384 
1385 	/* decide which send_cmd we're gonna use early */
1386 	etd->send_cmd = etd->hw_version >= 3 ? elantech_send_cmd :
1387 					       synaptics_send_cmd;
1388 
1389 	/* Turn on packet checking by default */
1390 	etd->paritycheck = 1;
1391 
1392 	/*
1393 	 * This firmware suffers from misreporting coordinates when
1394 	 * a touch action starts causing the mouse cursor or scrolled page
1395 	 * to jump. Enable a workaround.
1396 	 */
1397 	etd->jumpy_cursor =
1398 		(etd->fw_version == 0x020022 || etd->fw_version == 0x020600);
1399 
1400 	if (etd->hw_version > 1) {
1401 		/* For now show extra debug information */
1402 		etd->debug = 1;
1403 
1404 		if (etd->fw_version >= 0x020800)
1405 			etd->reports_pressure = true;
1406 	}
1407 
1408 	/*
1409 	 * The signatures of v3 and v4 packets change depending on the
1410 	 * value of this hardware flag.
1411 	 */
1412 	etd->crc_enabled = ((etd->fw_version & 0x4000) == 0x4000);
1413 
1414 	/* Enable real hardware resolution on hw_version 3 ? */
1415 	etd->set_hw_resolution = !dmi_check_system(no_hw_res_dmi_table);
1416 
1417 	return 0;
1418 }
1419 
1420 /*
1421  * Initialize the touchpad and create sysfs entries
1422  */
1423 int elantech_init(struct psmouse *psmouse)
1424 {
1425 	struct elantech_data *etd;
1426 	int i, error;
1427 	unsigned char param[3];
1428 
1429 	psmouse->private = etd = kzalloc(sizeof(struct elantech_data), GFP_KERNEL);
1430 	if (!etd)
1431 		return -ENOMEM;
1432 
1433 	psmouse_reset(psmouse);
1434 
1435 	etd->parity[0] = 1;
1436 	for (i = 1; i < 256; i++)
1437 		etd->parity[i] = etd->parity[i & (i - 1)] ^ 1;
1438 
1439 	/*
1440 	 * Do the version query again so we can store the result
1441 	 */
1442 	if (synaptics_send_cmd(psmouse, ETP_FW_VERSION_QUERY, param)) {
1443 		psmouse_err(psmouse, "failed to query firmware version.\n");
1444 		goto init_fail;
1445 	}
1446 	etd->fw_version = (param[0] << 16) | (param[1] << 8) | param[2];
1447 
1448 	if (elantech_set_properties(etd)) {
1449 		psmouse_err(psmouse, "unknown hardware version, aborting...\n");
1450 		goto init_fail;
1451 	}
1452 	psmouse_info(psmouse,
1453 		     "assuming hardware version %d (with firmware version 0x%02x%02x%02x)\n",
1454 		     etd->hw_version, param[0], param[1], param[2]);
1455 
1456 	if (etd->send_cmd(psmouse, ETP_CAPABILITIES_QUERY,
1457 	    etd->capabilities)) {
1458 		psmouse_err(psmouse, "failed to query capabilities.\n");
1459 		goto init_fail;
1460 	}
1461 	psmouse_info(psmouse,
1462 		     "Synaptics capabilities query result 0x%02x, 0x%02x, 0x%02x.\n",
1463 		     etd->capabilities[0], etd->capabilities[1],
1464 		     etd->capabilities[2]);
1465 
1466 	if (elantech_set_absolute_mode(psmouse)) {
1467 		psmouse_err(psmouse,
1468 			    "failed to put touchpad into absolute mode.\n");
1469 		goto init_fail;
1470 	}
1471 
1472 	if (elantech_set_input_params(psmouse)) {
1473 		psmouse_err(psmouse, "failed to query touchpad range.\n");
1474 		goto init_fail;
1475 	}
1476 
1477 	error = sysfs_create_group(&psmouse->ps2dev.serio->dev.kobj,
1478 				   &elantech_attr_group);
1479 	if (error) {
1480 		psmouse_err(psmouse,
1481 			    "failed to create sysfs attributes, error: %d.\n",
1482 			    error);
1483 		goto init_fail;
1484 	}
1485 
1486 	psmouse->protocol_handler = elantech_process_byte;
1487 	psmouse->disconnect = elantech_disconnect;
1488 	psmouse->reconnect = elantech_reconnect;
1489 	psmouse->pktsize = etd->hw_version > 1 ? 6 : 4;
1490 
1491 	return 0;
1492 
1493  init_fail:
1494 	kfree(etd);
1495 	return -1;
1496 }
1497