xref: /linux/drivers/input/mouse/elantech.c (revision b43ab901d671e3e3cad425ea5e9a3c74e266dcdd)
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/input/mt.h>
18 #include <linux/serio.h>
19 #include <linux/libps2.h>
20 #include "psmouse.h"
21 #include "elantech.h"
22 
23 #define elantech_debug(fmt, ...)					\
24 	do {								\
25 		if (etd->debug)						\
26 			psmouse_printk(KERN_DEBUG, psmouse,		\
27 					fmt, ##__VA_ARGS__);		\
28 	} while (0)
29 
30 /*
31  * Send a Synaptics style sliced query command
32  */
33 static int synaptics_send_cmd(struct psmouse *psmouse, unsigned char c,
34 				unsigned char *param)
35 {
36 	if (psmouse_sliced_command(psmouse, c) ||
37 	    ps2_command(&psmouse->ps2dev, param, PSMOUSE_CMD_GETINFO)) {
38 		psmouse_err(psmouse, "%s query 0x%02x failed.\n", __func__, c);
39 		return -1;
40 	}
41 
42 	return 0;
43 }
44 
45 /*
46  * V3 and later support this fast command
47  */
48 static int elantech_send_cmd(struct psmouse *psmouse, unsigned char c,
49 				unsigned char *param)
50 {
51 	struct ps2dev *ps2dev = &psmouse->ps2dev;
52 
53 	if (ps2_command(ps2dev, NULL, ETP_PS2_CUSTOM_COMMAND) ||
54 	    ps2_command(ps2dev, NULL, c) ||
55 	    ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO)) {
56 		psmouse_err(psmouse, "%s query 0x%02x failed.\n", __func__, c);
57 		return -1;
58 	}
59 
60 	return 0;
61 }
62 
63 /*
64  * A retrying version of ps2_command
65  */
66 static int elantech_ps2_command(struct psmouse *psmouse,
67 				unsigned char *param, int command)
68 {
69 	struct ps2dev *ps2dev = &psmouse->ps2dev;
70 	struct elantech_data *etd = psmouse->private;
71 	int rc;
72 	int tries = ETP_PS2_COMMAND_TRIES;
73 
74 	do {
75 		rc = ps2_command(ps2dev, param, command);
76 		if (rc == 0)
77 			break;
78 		tries--;
79 		elantech_debug("retrying ps2 command 0x%02x (%d).\n",
80 				command, tries);
81 		msleep(ETP_PS2_COMMAND_DELAY);
82 	} while (tries > 0);
83 
84 	if (rc)
85 		psmouse_err(psmouse, "ps2 command 0x%02x failed.\n", command);
86 
87 	return rc;
88 }
89 
90 /*
91  * Send an Elantech style special command to read a value from a register
92  */
93 static int elantech_read_reg(struct psmouse *psmouse, unsigned char reg,
94 				unsigned char *val)
95 {
96 	struct elantech_data *etd = psmouse->private;
97 	unsigned char param[3];
98 	int rc = 0;
99 
100 	if (reg < 0x07 || reg > 0x26)
101 		return -1;
102 
103 	if (reg > 0x11 && reg < 0x20)
104 		return -1;
105 
106 	switch (etd->hw_version) {
107 	case 1:
108 		if (psmouse_sliced_command(psmouse, ETP_REGISTER_READ) ||
109 		    psmouse_sliced_command(psmouse, reg) ||
110 		    ps2_command(&psmouse->ps2dev, param, PSMOUSE_CMD_GETINFO)) {
111 			rc = -1;
112 		}
113 		break;
114 
115 	case 2:
116 		if (elantech_ps2_command(psmouse,  NULL, ETP_PS2_CUSTOM_COMMAND) ||
117 		    elantech_ps2_command(psmouse,  NULL, ETP_REGISTER_READ) ||
118 		    elantech_ps2_command(psmouse,  NULL, ETP_PS2_CUSTOM_COMMAND) ||
119 		    elantech_ps2_command(psmouse,  NULL, reg) ||
120 		    elantech_ps2_command(psmouse, param, PSMOUSE_CMD_GETINFO)) {
121 			rc = -1;
122 		}
123 		break;
124 
125 	case 3 ... 4:
126 		if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
127 		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
128 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
129 		    elantech_ps2_command(psmouse, NULL, reg) ||
130 		    elantech_ps2_command(psmouse, param, PSMOUSE_CMD_GETINFO)) {
131 			rc = -1;
132 		}
133 		break;
134 	}
135 
136 	if (rc)
137 		psmouse_err(psmouse, "failed to read register 0x%02x.\n", reg);
138 	else if (etd->hw_version != 4)
139 		*val = param[0];
140 	else
141 		*val = param[1];
142 
143 	return rc;
144 }
145 
146 /*
147  * Send an Elantech style special command to write a register with a value
148  */
149 static int elantech_write_reg(struct psmouse *psmouse, unsigned char reg,
150 				unsigned char val)
151 {
152 	struct elantech_data *etd = psmouse->private;
153 	int rc = 0;
154 
155 	if (reg < 0x07 || reg > 0x26)
156 		return -1;
157 
158 	if (reg > 0x11 && reg < 0x20)
159 		return -1;
160 
161 	switch (etd->hw_version) {
162 	case 1:
163 		if (psmouse_sliced_command(psmouse, ETP_REGISTER_WRITE) ||
164 		    psmouse_sliced_command(psmouse, reg) ||
165 		    psmouse_sliced_command(psmouse, val) ||
166 		    ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_SETSCALE11)) {
167 			rc = -1;
168 		}
169 		break;
170 
171 	case 2:
172 		if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
173 		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_WRITE) ||
174 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
175 		    elantech_ps2_command(psmouse, NULL, reg) ||
176 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
177 		    elantech_ps2_command(psmouse, NULL, val) ||
178 		    elantech_ps2_command(psmouse, NULL, PSMOUSE_CMD_SETSCALE11)) {
179 			rc = -1;
180 		}
181 		break;
182 
183 	case 3:
184 		if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
185 		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
186 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
187 		    elantech_ps2_command(psmouse, NULL, reg) ||
188 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
189 		    elantech_ps2_command(psmouse, NULL, val) ||
190 		    elantech_ps2_command(psmouse, NULL, PSMOUSE_CMD_SETSCALE11)) {
191 			rc = -1;
192 		}
193 		break;
194 
195 	case 4:
196 		if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
197 		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
198 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
199 		    elantech_ps2_command(psmouse, NULL, reg) ||
200 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
201 		    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
202 		    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
203 		    elantech_ps2_command(psmouse, NULL, val) ||
204 		    elantech_ps2_command(psmouse, NULL, PSMOUSE_CMD_SETSCALE11)) {
205 			rc = -1;
206 		}
207 		break;
208 	}
209 
210 	if (rc)
211 		psmouse_err(psmouse,
212 			    "failed to write register 0x%02x with value 0x%02x.\n",
213 			    reg, val);
214 
215 	return rc;
216 }
217 
218 /*
219  * Dump a complete mouse movement packet to the syslog
220  */
221 static void elantech_packet_dump(struct psmouse *psmouse)
222 {
223 	int	i;
224 
225 	psmouse_printk(KERN_DEBUG, psmouse, "PS/2 packet [");
226 	for (i = 0; i < psmouse->pktsize; i++)
227 		printk("%s0x%02x ", i ? ", " : " ", psmouse->packet[i]);
228 	printk("]\n");
229 }
230 
231 /*
232  * Interpret complete data packets and report absolute mode input events for
233  * hardware version 1. (4 byte packets)
234  */
235 static void elantech_report_absolute_v1(struct psmouse *psmouse)
236 {
237 	struct input_dev *dev = psmouse->dev;
238 	struct elantech_data *etd = psmouse->private;
239 	unsigned char *packet = psmouse->packet;
240 	int fingers;
241 
242 	if (etd->fw_version < 0x020000) {
243 		/*
244 		 * byte 0:  D   U  p1  p2   1  p3   R   L
245 		 * byte 1:  f   0  th  tw  x9  x8  y9  y8
246 		 */
247 		fingers = ((packet[1] & 0x80) >> 7) +
248 				((packet[1] & 0x30) >> 4);
249 	} else {
250 		/*
251 		 * byte 0: n1  n0  p2  p1   1  p3   R   L
252 		 * byte 1:  0   0   0   0  x9  x8  y9  y8
253 		 */
254 		fingers = (packet[0] & 0xc0) >> 6;
255 	}
256 
257 	if (etd->jumpy_cursor) {
258 		if (fingers != 1) {
259 			etd->single_finger_reports = 0;
260 		} else if (etd->single_finger_reports < 2) {
261 			/* Discard first 2 reports of one finger, bogus */
262 			etd->single_finger_reports++;
263 			elantech_debug("discarding packet\n");
264 			return;
265 		}
266 	}
267 
268 	input_report_key(dev, BTN_TOUCH, fingers != 0);
269 
270 	/*
271 	 * byte 2: x7  x6  x5  x4  x3  x2  x1  x0
272 	 * byte 3: y7  y6  y5  y4  y3  y2  y1  y0
273 	 */
274 	if (fingers) {
275 		input_report_abs(dev, ABS_X,
276 			((packet[1] & 0x0c) << 6) | packet[2]);
277 		input_report_abs(dev, ABS_Y,
278 			etd->y_max - (((packet[1] & 0x03) << 8) | packet[3]));
279 	}
280 
281 	input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
282 	input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
283 	input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);
284 	input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
285 	input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);
286 
287 	if (etd->fw_version < 0x020000 &&
288 	    (etd->capabilities[0] & ETP_CAP_HAS_ROCKER)) {
289 		/* rocker up */
290 		input_report_key(dev, BTN_FORWARD, packet[0] & 0x40);
291 		/* rocker down */
292 		input_report_key(dev, BTN_BACK, packet[0] & 0x80);
293 	}
294 
295 	input_sync(dev);
296 }
297 
298 static void elantech_set_slot(struct input_dev *dev, int slot, bool active,
299 			      unsigned int x, unsigned int y)
300 {
301 	input_mt_slot(dev, slot);
302 	input_mt_report_slot_state(dev, MT_TOOL_FINGER, active);
303 	if (active) {
304 		input_report_abs(dev, ABS_MT_POSITION_X, x);
305 		input_report_abs(dev, ABS_MT_POSITION_Y, y);
306 	}
307 }
308 
309 /* x1 < x2 and y1 < y2 when two fingers, x = y = 0 when not pressed */
310 static void elantech_report_semi_mt_data(struct input_dev *dev,
311 					 unsigned int num_fingers,
312 					 unsigned int x1, unsigned int y1,
313 					 unsigned int x2, unsigned int y2)
314 {
315 	elantech_set_slot(dev, 0, num_fingers != 0, x1, y1);
316 	elantech_set_slot(dev, 1, num_fingers == 2, x2, y2);
317 }
318 
319 /*
320  * Interpret complete data packets and report absolute mode input events for
321  * hardware version 2. (6 byte packets)
322  */
323 static void elantech_report_absolute_v2(struct psmouse *psmouse)
324 {
325 	struct elantech_data *etd = psmouse->private;
326 	struct input_dev *dev = psmouse->dev;
327 	unsigned char *packet = psmouse->packet;
328 	unsigned int fingers, x1 = 0, y1 = 0, x2 = 0, y2 = 0;
329 	unsigned int width = 0, pres = 0;
330 
331 	/* byte 0: n1  n0   .   .   .   .   R   L */
332 	fingers = (packet[0] & 0xc0) >> 6;
333 
334 	switch (fingers) {
335 	case 3:
336 		/*
337 		 * Same as one finger, except report of more than 3 fingers:
338 		 * byte 3:  n4  .   w1  w0   .   .   .   .
339 		 */
340 		if (packet[3] & 0x80)
341 			fingers = 4;
342 		/* pass through... */
343 	case 1:
344 		/*
345 		 * byte 1:  .   .   .   .  x11 x10 x9  x8
346 		 * byte 2: x7  x6  x5  x4  x4  x2  x1  x0
347 		 */
348 		x1 = ((packet[1] & 0x0f) << 8) | packet[2];
349 		/*
350 		 * byte 4:  .   .   .   .  y11 y10 y9  y8
351 		 * byte 5: y7  y6  y5  y4  y3  y2  y1  y0
352 		 */
353 		y1 = etd->y_max - (((packet[4] & 0x0f) << 8) | packet[5]);
354 
355 		pres = (packet[1] & 0xf0) | ((packet[4] & 0xf0) >> 4);
356 		width = ((packet[0] & 0x30) >> 2) | ((packet[3] & 0x30) >> 4);
357 		break;
358 
359 	case 2:
360 		/*
361 		 * The coordinate of each finger is reported separately
362 		 * with a lower resolution for two finger touches:
363 		 * byte 0:  .   .  ay8 ax8  .   .   .   .
364 		 * byte 1: ax7 ax6 ax5 ax4 ax3 ax2 ax1 ax0
365 		 */
366 		x1 = (((packet[0] & 0x10) << 4) | packet[1]) << 2;
367 		/* byte 2: ay7 ay6 ay5 ay4 ay3 ay2 ay1 ay0 */
368 		y1 = etd->y_max -
369 			((((packet[0] & 0x20) << 3) | packet[2]) << 2);
370 		/*
371 		 * byte 3:  .   .  by8 bx8  .   .   .   .
372 		 * byte 4: bx7 bx6 bx5 bx4 bx3 bx2 bx1 bx0
373 		 */
374 		x2 = (((packet[3] & 0x10) << 4) | packet[4]) << 2;
375 		/* byte 5: by7 by8 by5 by4 by3 by2 by1 by0 */
376 		y2 = etd->y_max -
377 			((((packet[3] & 0x20) << 3) | packet[5]) << 2);
378 
379 		/* Unknown so just report sensible values */
380 		pres = 127;
381 		width = 7;
382 		break;
383 	}
384 
385 	input_report_key(dev, BTN_TOUCH, fingers != 0);
386 	if (fingers != 0) {
387 		input_report_abs(dev, ABS_X, x1);
388 		input_report_abs(dev, ABS_Y, y1);
389 	}
390 	elantech_report_semi_mt_data(dev, fingers, x1, y1, x2, y2);
391 	input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
392 	input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
393 	input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);
394 	input_report_key(dev, BTN_TOOL_QUADTAP, fingers == 4);
395 	input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
396 	input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);
397 	if (etd->reports_pressure) {
398 		input_report_abs(dev, ABS_PRESSURE, pres);
399 		input_report_abs(dev, ABS_TOOL_WIDTH, width);
400 	}
401 
402 	input_sync(dev);
403 }
404 
405 /*
406  * Interpret complete data packets and report absolute mode input events for
407  * hardware version 3. (12 byte packets for two fingers)
408  */
409 static void elantech_report_absolute_v3(struct psmouse *psmouse,
410 					int packet_type)
411 {
412 	struct input_dev *dev = psmouse->dev;
413 	struct elantech_data *etd = psmouse->private;
414 	unsigned char *packet = psmouse->packet;
415 	unsigned int fingers = 0, x1 = 0, y1 = 0, x2 = 0, y2 = 0;
416 	unsigned int width = 0, pres = 0;
417 
418 	/* byte 0: n1  n0   .   .   .   .   R   L */
419 	fingers = (packet[0] & 0xc0) >> 6;
420 
421 	switch (fingers) {
422 	case 3:
423 	case 1:
424 		/*
425 		 * byte 1:  .   .   .   .  x11 x10 x9  x8
426 		 * byte 2: x7  x6  x5  x4  x4  x2  x1  x0
427 		 */
428 		x1 = ((packet[1] & 0x0f) << 8) | packet[2];
429 		/*
430 		 * byte 4:  .   .   .   .  y11 y10 y9  y8
431 		 * byte 5: y7  y6  y5  y4  y3  y2  y1  y0
432 		 */
433 		y1 = etd->y_max - (((packet[4] & 0x0f) << 8) | packet[5]);
434 		break;
435 
436 	case 2:
437 		if (packet_type == PACKET_V3_HEAD) {
438 			/*
439 			 * byte 1:   .    .    .    .  ax11 ax10 ax9  ax8
440 			 * byte 2: ax7  ax6  ax5  ax4  ax3  ax2  ax1  ax0
441 			 */
442 			etd->mt[0].x = ((packet[1] & 0x0f) << 8) | packet[2];
443 			/*
444 			 * byte 4:   .    .    .    .  ay11 ay10 ay9  ay8
445 			 * byte 5: ay7  ay6  ay5  ay4  ay3  ay2  ay1  ay0
446 			 */
447 			etd->mt[0].y = etd->y_max -
448 				(((packet[4] & 0x0f) << 8) | packet[5]);
449 			/*
450 			 * wait for next packet
451 			 */
452 			return;
453 		}
454 
455 		/* packet_type == PACKET_V3_TAIL */
456 		x1 = etd->mt[0].x;
457 		y1 = etd->mt[0].y;
458 		x2 = ((packet[1] & 0x0f) << 8) | packet[2];
459 		y2 = etd->y_max - (((packet[4] & 0x0f) << 8) | packet[5]);
460 		break;
461 	}
462 
463 	pres = (packet[1] & 0xf0) | ((packet[4] & 0xf0) >> 4);
464 	width = ((packet[0] & 0x30) >> 2) | ((packet[3] & 0x30) >> 4);
465 
466 	input_report_key(dev, BTN_TOUCH, fingers != 0);
467 	if (fingers != 0) {
468 		input_report_abs(dev, ABS_X, x1);
469 		input_report_abs(dev, ABS_Y, y1);
470 	}
471 	elantech_report_semi_mt_data(dev, fingers, x1, y1, x2, y2);
472 	input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
473 	input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
474 	input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);
475 	input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
476 	input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);
477 	input_report_abs(dev, ABS_PRESSURE, pres);
478 	input_report_abs(dev, ABS_TOOL_WIDTH, width);
479 
480 	input_sync(dev);
481 }
482 
483 static void elantech_input_sync_v4(struct psmouse *psmouse)
484 {
485 	struct input_dev *dev = psmouse->dev;
486 	unsigned char *packet = psmouse->packet;
487 
488 	input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
489 	input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);
490 	input_mt_report_pointer_emulation(dev, true);
491 	input_sync(dev);
492 }
493 
494 static void process_packet_status_v4(struct psmouse *psmouse)
495 {
496 	struct input_dev *dev = psmouse->dev;
497 	unsigned char *packet = psmouse->packet;
498 	unsigned fingers;
499 	int i;
500 
501 	/* notify finger state change */
502 	fingers = packet[1] & 0x1f;
503 	for (i = 0; i < ETP_MAX_FINGERS; i++) {
504 		if ((fingers & (1 << i)) == 0) {
505 			input_mt_slot(dev, i);
506 			input_mt_report_slot_state(dev, MT_TOOL_FINGER, false);
507 		}
508 	}
509 
510 	elantech_input_sync_v4(psmouse);
511 }
512 
513 static void process_packet_head_v4(struct psmouse *psmouse)
514 {
515 	struct input_dev *dev = psmouse->dev;
516 	struct elantech_data *etd = psmouse->private;
517 	unsigned char *packet = psmouse->packet;
518 	int id = ((packet[3] & 0xe0) >> 5) - 1;
519 	int pres, traces;
520 
521 	if (id < 0)
522 		return;
523 
524 	etd->mt[id].x = ((packet[1] & 0x0f) << 8) | packet[2];
525 	etd->mt[id].y = etd->y_max - (((packet[4] & 0x0f) << 8) | packet[5]);
526 	pres = (packet[1] & 0xf0) | ((packet[4] & 0xf0) >> 4);
527 	traces = (packet[0] & 0xf0) >> 4;
528 
529 	input_mt_slot(dev, id);
530 	input_mt_report_slot_state(dev, MT_TOOL_FINGER, true);
531 
532 	input_report_abs(dev, ABS_MT_POSITION_X, etd->mt[id].x);
533 	input_report_abs(dev, ABS_MT_POSITION_Y, etd->mt[id].y);
534 	input_report_abs(dev, ABS_MT_PRESSURE, pres);
535 	input_report_abs(dev, ABS_MT_TOUCH_MAJOR, traces * etd->width);
536 	/* report this for backwards compatibility */
537 	input_report_abs(dev, ABS_TOOL_WIDTH, traces);
538 
539 	elantech_input_sync_v4(psmouse);
540 }
541 
542 static void process_packet_motion_v4(struct psmouse *psmouse)
543 {
544 	struct input_dev *dev = psmouse->dev;
545 	struct elantech_data *etd = psmouse->private;
546 	unsigned char *packet = psmouse->packet;
547 	int weight, delta_x1 = 0, delta_y1 = 0, delta_x2 = 0, delta_y2 = 0;
548 	int id, sid;
549 
550 	id = ((packet[0] & 0xe0) >> 5) - 1;
551 	if (id < 0)
552 		return;
553 
554 	sid = ((packet[3] & 0xe0) >> 5) - 1;
555 	weight = (packet[0] & 0x10) ? ETP_WEIGHT_VALUE : 1;
556 	/*
557 	 * Motion packets give us the delta of x, y values of specific fingers,
558 	 * but in two's complement. Let the compiler do the conversion for us.
559 	 * Also _enlarge_ the numbers to int, in case of overflow.
560 	 */
561 	delta_x1 = (signed char)packet[1];
562 	delta_y1 = (signed char)packet[2];
563 	delta_x2 = (signed char)packet[4];
564 	delta_y2 = (signed char)packet[5];
565 
566 	etd->mt[id].x += delta_x1 * weight;
567 	etd->mt[id].y -= delta_y1 * weight;
568 	input_mt_slot(dev, id);
569 	input_report_abs(dev, ABS_MT_POSITION_X, etd->mt[id].x);
570 	input_report_abs(dev, ABS_MT_POSITION_Y, etd->mt[id].y);
571 
572 	if (sid >= 0) {
573 		etd->mt[sid].x += delta_x2 * weight;
574 		etd->mt[sid].y -= delta_y2 * weight;
575 		input_mt_slot(dev, sid);
576 		input_report_abs(dev, ABS_MT_POSITION_X, etd->mt[sid].x);
577 		input_report_abs(dev, ABS_MT_POSITION_Y, etd->mt[sid].y);
578 	}
579 
580 	elantech_input_sync_v4(psmouse);
581 }
582 
583 static void elantech_report_absolute_v4(struct psmouse *psmouse,
584 					int packet_type)
585 {
586 	switch (packet_type) {
587 	case PACKET_V4_STATUS:
588 		process_packet_status_v4(psmouse);
589 		break;
590 
591 	case PACKET_V4_HEAD:
592 		process_packet_head_v4(psmouse);
593 		break;
594 
595 	case PACKET_V4_MOTION:
596 		process_packet_motion_v4(psmouse);
597 		break;
598 
599 	case PACKET_UNKNOWN:
600 	default:
601 		/* impossible to get here */
602 		break;
603 	}
604 }
605 
606 static int elantech_packet_check_v1(struct psmouse *psmouse)
607 {
608 	struct elantech_data *etd = psmouse->private;
609 	unsigned char *packet = psmouse->packet;
610 	unsigned char p1, p2, p3;
611 
612 	/* Parity bits are placed differently */
613 	if (etd->fw_version < 0x020000) {
614 		/* byte 0:  D   U  p1  p2   1  p3   R   L */
615 		p1 = (packet[0] & 0x20) >> 5;
616 		p2 = (packet[0] & 0x10) >> 4;
617 	} else {
618 		/* byte 0: n1  n0  p2  p1   1  p3   R   L */
619 		p1 = (packet[0] & 0x10) >> 4;
620 		p2 = (packet[0] & 0x20) >> 5;
621 	}
622 
623 	p3 = (packet[0] & 0x04) >> 2;
624 
625 	return etd->parity[packet[1]] == p1 &&
626 	       etd->parity[packet[2]] == p2 &&
627 	       etd->parity[packet[3]] == p3;
628 }
629 
630 static int elantech_debounce_check_v2(struct psmouse *psmouse)
631 {
632         /*
633          * When we encounter packet that matches this exactly, it means the
634          * hardware is in debounce status. Just ignore the whole packet.
635          */
636         const u8 debounce_packet[] = { 0x84, 0xff, 0xff, 0x02, 0xff, 0xff };
637         unsigned char *packet = psmouse->packet;
638 
639         return !memcmp(packet, debounce_packet, sizeof(debounce_packet));
640 }
641 
642 static int elantech_packet_check_v2(struct psmouse *psmouse)
643 {
644 	struct elantech_data *etd = psmouse->private;
645 	unsigned char *packet = psmouse->packet;
646 
647 	/*
648 	 * V2 hardware has two flavors. Older ones that do not report pressure,
649 	 * and newer ones that reports pressure and width. With newer ones, all
650 	 * packets (1, 2, 3 finger touch) have the same constant bits. With
651 	 * older ones, 1/3 finger touch packets and 2 finger touch packets
652 	 * have different constant bits.
653 	 * With all three cases, if the constant bits are not exactly what I
654 	 * expected, I consider them invalid.
655 	 */
656 	if (etd->reports_pressure)
657 		return (packet[0] & 0x0c) == 0x04 &&
658 		       (packet[3] & 0x0f) == 0x02;
659 
660 	if ((packet[0] & 0xc0) == 0x80)
661 		return (packet[0] & 0x0c) == 0x0c &&
662 		       (packet[3] & 0x0e) == 0x08;
663 
664 	return (packet[0] & 0x3c) == 0x3c &&
665 	       (packet[1] & 0xf0) == 0x00 &&
666 	       (packet[3] & 0x3e) == 0x38 &&
667 	       (packet[4] & 0xf0) == 0x00;
668 }
669 
670 /*
671  * We check the constant bits to determine what packet type we get,
672  * so packet checking is mandatory for v3 and later hardware.
673  */
674 static int elantech_packet_check_v3(struct psmouse *psmouse)
675 {
676 	const u8 debounce_packet[] = { 0xc4, 0xff, 0xff, 0x02, 0xff, 0xff };
677 	unsigned char *packet = psmouse->packet;
678 
679 	/*
680 	 * check debounce first, it has the same signature in byte 0
681 	 * and byte 3 as PACKET_V3_HEAD.
682 	 */
683 	if (!memcmp(packet, debounce_packet, sizeof(debounce_packet)))
684 		return PACKET_DEBOUNCE;
685 
686 	if ((packet[0] & 0x0c) == 0x04 && (packet[3] & 0xcf) == 0x02)
687 		return PACKET_V3_HEAD;
688 
689 	if ((packet[0] & 0x0c) == 0x0c && (packet[3] & 0xce) == 0x0c)
690 		return PACKET_V3_TAIL;
691 
692 	return PACKET_UNKNOWN;
693 }
694 
695 static int elantech_packet_check_v4(struct psmouse *psmouse)
696 {
697 	unsigned char *packet = psmouse->packet;
698 
699 	if ((packet[0] & 0x0c) == 0x04 &&
700 	    (packet[3] & 0x1f) == 0x11)
701 		return PACKET_V4_HEAD;
702 
703 	if ((packet[0] & 0x0c) == 0x04 &&
704 	    (packet[3] & 0x1f) == 0x12)
705 		return PACKET_V4_MOTION;
706 
707 	if ((packet[0] & 0x0c) == 0x04 &&
708 	    (packet[3] & 0x1f) == 0x10)
709 		return PACKET_V4_STATUS;
710 
711 	return PACKET_UNKNOWN;
712 }
713 
714 /*
715  * Process byte stream from mouse and handle complete packets
716  */
717 static psmouse_ret_t elantech_process_byte(struct psmouse *psmouse)
718 {
719 	struct elantech_data *etd = psmouse->private;
720 	int packet_type;
721 
722 	if (psmouse->pktcnt < psmouse->pktsize)
723 		return PSMOUSE_GOOD_DATA;
724 
725 	if (etd->debug > 1)
726 		elantech_packet_dump(psmouse);
727 
728 	switch (etd->hw_version) {
729 	case 1:
730 		if (etd->paritycheck && !elantech_packet_check_v1(psmouse))
731 			return PSMOUSE_BAD_DATA;
732 
733 		elantech_report_absolute_v1(psmouse);
734 		break;
735 
736 	case 2:
737 		/* ignore debounce */
738 		if (elantech_debounce_check_v2(psmouse))
739 			return PSMOUSE_FULL_PACKET;
740 
741 		if (etd->paritycheck && !elantech_packet_check_v2(psmouse))
742 			return PSMOUSE_BAD_DATA;
743 
744 		elantech_report_absolute_v2(psmouse);
745 		break;
746 
747 	case 3:
748 		packet_type = elantech_packet_check_v3(psmouse);
749 		/* ignore debounce */
750 		if (packet_type == PACKET_DEBOUNCE)
751 			return PSMOUSE_FULL_PACKET;
752 
753 		if (packet_type == PACKET_UNKNOWN)
754 			return PSMOUSE_BAD_DATA;
755 
756 		elantech_report_absolute_v3(psmouse, packet_type);
757 		break;
758 
759 	case 4:
760 		packet_type = elantech_packet_check_v4(psmouse);
761 		if (packet_type == PACKET_UNKNOWN)
762 			return PSMOUSE_BAD_DATA;
763 
764 		elantech_report_absolute_v4(psmouse, packet_type);
765 		break;
766 	}
767 
768 	return PSMOUSE_FULL_PACKET;
769 }
770 
771 /*
772  * Put the touchpad into absolute mode
773  */
774 static int elantech_set_absolute_mode(struct psmouse *psmouse)
775 {
776 	struct elantech_data *etd = psmouse->private;
777 	unsigned char val;
778 	int tries = ETP_READ_BACK_TRIES;
779 	int rc = 0;
780 
781 	switch (etd->hw_version) {
782 	case 1:
783 		etd->reg_10 = 0x16;
784 		etd->reg_11 = 0x8f;
785 		if (elantech_write_reg(psmouse, 0x10, etd->reg_10) ||
786 		    elantech_write_reg(psmouse, 0x11, etd->reg_11)) {
787 			rc = -1;
788 		}
789 		break;
790 
791 	case 2:
792 					/* Windows driver values */
793 		etd->reg_10 = 0x54;
794 		etd->reg_11 = 0x88;	/* 0x8a */
795 		etd->reg_21 = 0x60;	/* 0x00 */
796 		if (elantech_write_reg(psmouse, 0x10, etd->reg_10) ||
797 		    elantech_write_reg(psmouse, 0x11, etd->reg_11) ||
798 		    elantech_write_reg(psmouse, 0x21, etd->reg_21)) {
799 			rc = -1;
800 		}
801 		break;
802 
803 	case 3:
804 		etd->reg_10 = 0x0b;
805 		if (elantech_write_reg(psmouse, 0x10, etd->reg_10))
806 			rc = -1;
807 
808 		break;
809 
810 	case 4:
811 		etd->reg_07 = 0x01;
812 		if (elantech_write_reg(psmouse, 0x07, etd->reg_07))
813 			rc = -1;
814 
815 		goto skip_readback_reg_10; /* v4 has no reg 0x10 to read */
816 	}
817 
818 	if (rc == 0) {
819 		/*
820 		 * Read back reg 0x10. For hardware version 1 we must make
821 		 * sure the absolute mode bit is set. For hardware version 2
822 		 * the touchpad is probably initializing and not ready until
823 		 * we read back the value we just wrote.
824 		 */
825 		do {
826 			rc = elantech_read_reg(psmouse, 0x10, &val);
827 			if (rc == 0)
828 				break;
829 			tries--;
830 			elantech_debug("retrying read (%d).\n", tries);
831 			msleep(ETP_READ_BACK_DELAY);
832 		} while (tries > 0);
833 
834 		if (rc) {
835 			psmouse_err(psmouse,
836 				    "failed to read back register 0x10.\n");
837 		} else if (etd->hw_version == 1 &&
838 			   !(val & ETP_R10_ABSOLUTE_MODE)) {
839 			psmouse_err(psmouse,
840 				    "touchpad refuses to switch to absolute mode.\n");
841 			rc = -1;
842 		}
843 	}
844 
845  skip_readback_reg_10:
846 	if (rc)
847 		psmouse_err(psmouse, "failed to initialise registers.\n");
848 
849 	return rc;
850 }
851 
852 static int elantech_set_range(struct psmouse *psmouse,
853 			      unsigned int *x_min, unsigned int *y_min,
854 			      unsigned int *x_max, unsigned int *y_max,
855 			      unsigned int *width)
856 {
857 	struct elantech_data *etd = psmouse->private;
858 	unsigned char param[3];
859 	unsigned char traces;
860 
861 	switch (etd->hw_version) {
862 	case 1:
863 		*x_min = ETP_XMIN_V1;
864 		*y_min = ETP_YMIN_V1;
865 		*x_max = ETP_XMAX_V1;
866 		*y_max = ETP_YMAX_V1;
867 		break;
868 
869 	case 2:
870 		if (etd->fw_version == 0x020800 ||
871 		    etd->fw_version == 0x020b00 ||
872 		    etd->fw_version == 0x020030) {
873 			*x_min = ETP_XMIN_V2;
874 			*y_min = ETP_YMIN_V2;
875 			*x_max = ETP_XMAX_V2;
876 			*y_max = ETP_YMAX_V2;
877 		} else {
878 			int i;
879 			int fixed_dpi;
880 
881 			i = (etd->fw_version > 0x020800 &&
882 			     etd->fw_version < 0x020900) ? 1 : 2;
883 
884 			if (etd->send_cmd(psmouse, ETP_FW_ID_QUERY, param))
885 				return -1;
886 
887 			fixed_dpi = param[1] & 0x10;
888 
889 			if (((etd->fw_version >> 16) == 0x14) && fixed_dpi) {
890 				if (etd->send_cmd(psmouse, ETP_SAMPLE_QUERY, param))
891 					return -1;
892 
893 				*x_max = (etd->capabilities[1] - i) * param[1] / 2;
894 				*y_max = (etd->capabilities[2] - i) * param[2] / 2;
895 			} else if (etd->fw_version == 0x040216) {
896 				*x_max = 819;
897 				*y_max = 405;
898 			} else if (etd->fw_version == 0x040219 || etd->fw_version == 0x040215) {
899 				*x_max = 900;
900 				*y_max = 500;
901 			} else {
902 				*x_max = (etd->capabilities[1] - i) * 64;
903 				*y_max = (etd->capabilities[2] - i) * 64;
904 			}
905 		}
906 		break;
907 
908 	case 3:
909 		if (etd->send_cmd(psmouse, ETP_FW_ID_QUERY, param))
910 			return -1;
911 
912 		*x_max = (0x0f & param[0]) << 8 | param[1];
913 		*y_max = (0xf0 & param[0]) << 4 | param[2];
914 		break;
915 
916 	case 4:
917 		if (etd->send_cmd(psmouse, ETP_FW_ID_QUERY, param))
918 			return -1;
919 
920 		*x_max = (0x0f & param[0]) << 8 | param[1];
921 		*y_max = (0xf0 & param[0]) << 4 | param[2];
922 		traces = etd->capabilities[1];
923 		if ((traces < 2) || (traces > *x_max))
924 			return -1;
925 
926 		*width = *x_max / (traces - 1);
927 		break;
928 	}
929 
930 	return 0;
931 }
932 
933 /*
934  * (value from firmware) * 10 + 790 = dpi
935  * we also have to convert dpi to dots/mm (*10/254 to avoid floating point)
936  */
937 static unsigned int elantech_convert_res(unsigned int val)
938 {
939 	return (val * 10 + 790) * 10 / 254;
940 }
941 
942 static int elantech_get_resolution_v4(struct psmouse *psmouse,
943 				      unsigned int *x_res,
944 				      unsigned int *y_res)
945 {
946 	unsigned char param[3];
947 
948 	if (elantech_send_cmd(psmouse, ETP_RESOLUTION_QUERY, param))
949 		return -1;
950 
951 	*x_res = elantech_convert_res(param[1] & 0x0f);
952 	*y_res = elantech_convert_res((param[1] & 0xf0) >> 4);
953 
954 	return 0;
955 }
956 
957 /*
958  * Set the appropriate event bits for the input subsystem
959  */
960 static int elantech_set_input_params(struct psmouse *psmouse)
961 {
962 	struct input_dev *dev = psmouse->dev;
963 	struct elantech_data *etd = psmouse->private;
964 	unsigned int x_min = 0, y_min = 0, x_max = 0, y_max = 0, width = 0;
965 	unsigned int x_res = 0, y_res = 0;
966 
967 	if (elantech_set_range(psmouse, &x_min, &y_min, &x_max, &y_max, &width))
968 		return -1;
969 
970 	__set_bit(EV_KEY, dev->evbit);
971 	__set_bit(EV_ABS, dev->evbit);
972 	__clear_bit(EV_REL, dev->evbit);
973 
974 	__set_bit(BTN_LEFT, dev->keybit);
975 	__set_bit(BTN_RIGHT, dev->keybit);
976 
977 	__set_bit(BTN_TOUCH, dev->keybit);
978 	__set_bit(BTN_TOOL_FINGER, dev->keybit);
979 	__set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
980 	__set_bit(BTN_TOOL_TRIPLETAP, dev->keybit);
981 
982 	switch (etd->hw_version) {
983 	case 1:
984 		/* Rocker button */
985 		if (etd->fw_version < 0x020000 &&
986 		    (etd->capabilities[0] & ETP_CAP_HAS_ROCKER)) {
987 			__set_bit(BTN_FORWARD, dev->keybit);
988 			__set_bit(BTN_BACK, dev->keybit);
989 		}
990 		input_set_abs_params(dev, ABS_X, x_min, x_max, 0, 0);
991 		input_set_abs_params(dev, ABS_Y, y_min, y_max, 0, 0);
992 		break;
993 
994 	case 2:
995 		__set_bit(BTN_TOOL_QUADTAP, dev->keybit);
996 		__set_bit(INPUT_PROP_SEMI_MT, dev->propbit);
997 		/* fall through */
998 	case 3:
999 		input_set_abs_params(dev, ABS_X, x_min, x_max, 0, 0);
1000 		input_set_abs_params(dev, ABS_Y, y_min, y_max, 0, 0);
1001 		if (etd->reports_pressure) {
1002 			input_set_abs_params(dev, ABS_PRESSURE, ETP_PMIN_V2,
1003 					     ETP_PMAX_V2, 0, 0);
1004 			input_set_abs_params(dev, ABS_TOOL_WIDTH, ETP_WMIN_V2,
1005 					     ETP_WMAX_V2, 0, 0);
1006 		}
1007 		input_mt_init_slots(dev, 2);
1008 		input_set_abs_params(dev, ABS_MT_POSITION_X, x_min, x_max, 0, 0);
1009 		input_set_abs_params(dev, ABS_MT_POSITION_Y, y_min, y_max, 0, 0);
1010 		break;
1011 
1012 	case 4:
1013 		if (elantech_get_resolution_v4(psmouse, &x_res, &y_res)) {
1014 			/*
1015 			 * if query failed, print a warning and leave the values
1016 			 * zero to resemble synaptics.c behavior.
1017 			 */
1018 			psmouse_warn(psmouse, "couldn't query resolution data.\n");
1019 		}
1020 
1021 		__set_bit(BTN_TOOL_QUADTAP, dev->keybit);
1022 		/* For X to recognize me as touchpad. */
1023 		input_set_abs_params(dev, ABS_X, x_min, x_max, 0, 0);
1024 		input_set_abs_params(dev, ABS_Y, y_min, y_max, 0, 0);
1025 		input_abs_set_res(dev, ABS_X, x_res);
1026 		input_abs_set_res(dev, ABS_Y, y_res);
1027 		/*
1028 		 * range of pressure and width is the same as v2,
1029 		 * report ABS_PRESSURE, ABS_TOOL_WIDTH for compatibility.
1030 		 */
1031 		input_set_abs_params(dev, ABS_PRESSURE, ETP_PMIN_V2,
1032 				     ETP_PMAX_V2, 0, 0);
1033 		input_set_abs_params(dev, ABS_TOOL_WIDTH, ETP_WMIN_V2,
1034 				     ETP_WMAX_V2, 0, 0);
1035 		/* Multitouch capable pad, up to 5 fingers. */
1036 		input_mt_init_slots(dev, ETP_MAX_FINGERS);
1037 		input_set_abs_params(dev, ABS_MT_POSITION_X, x_min, x_max, 0, 0);
1038 		input_set_abs_params(dev, ABS_MT_POSITION_Y, y_min, y_max, 0, 0);
1039 		input_abs_set_res(dev, ABS_MT_POSITION_X, x_res);
1040 		input_abs_set_res(dev, ABS_MT_POSITION_Y, y_res);
1041 		input_set_abs_params(dev, ABS_MT_PRESSURE, ETP_PMIN_V2,
1042 				     ETP_PMAX_V2, 0, 0);
1043 		/*
1044 		 * The firmware reports how many trace lines the finger spans,
1045 		 * convert to surface unit as Protocol-B requires.
1046 		 */
1047 		input_set_abs_params(dev, ABS_MT_TOUCH_MAJOR, 0,
1048 				     ETP_WMAX_V2 * width, 0, 0);
1049 		break;
1050 	}
1051 
1052 	etd->y_max = y_max;
1053 	etd->width = width;
1054 
1055 	return 0;
1056 }
1057 
1058 struct elantech_attr_data {
1059 	size_t		field_offset;
1060 	unsigned char	reg;
1061 };
1062 
1063 /*
1064  * Display a register value by reading a sysfs entry
1065  */
1066 static ssize_t elantech_show_int_attr(struct psmouse *psmouse, void *data,
1067 					char *buf)
1068 {
1069 	struct elantech_data *etd = psmouse->private;
1070 	struct elantech_attr_data *attr = data;
1071 	unsigned char *reg = (unsigned char *) etd + attr->field_offset;
1072 	int rc = 0;
1073 
1074 	if (attr->reg)
1075 		rc = elantech_read_reg(psmouse, attr->reg, reg);
1076 
1077 	return sprintf(buf, "0x%02x\n", (attr->reg && rc) ? -1 : *reg);
1078 }
1079 
1080 /*
1081  * Write a register value by writing a sysfs entry
1082  */
1083 static ssize_t elantech_set_int_attr(struct psmouse *psmouse,
1084 				     void *data, const char *buf, size_t count)
1085 {
1086 	struct elantech_data *etd = psmouse->private;
1087 	struct elantech_attr_data *attr = data;
1088 	unsigned char *reg = (unsigned char *) etd + attr->field_offset;
1089 	unsigned char value;
1090 	int err;
1091 
1092 	err = kstrtou8(buf, 16, &value);
1093 	if (err)
1094 		return err;
1095 
1096 	/* Do we need to preserve some bits for version 2 hardware too? */
1097 	if (etd->hw_version == 1) {
1098 		if (attr->reg == 0x10)
1099 			/* Force absolute mode always on */
1100 			value |= ETP_R10_ABSOLUTE_MODE;
1101 		else if (attr->reg == 0x11)
1102 			/* Force 4 byte mode always on */
1103 			value |= ETP_R11_4_BYTE_MODE;
1104 	}
1105 
1106 	if (!attr->reg || elantech_write_reg(psmouse, attr->reg, value) == 0)
1107 		*reg = value;
1108 
1109 	return count;
1110 }
1111 
1112 #define ELANTECH_INT_ATTR(_name, _register)				\
1113 	static struct elantech_attr_data elantech_attr_##_name = {	\
1114 		.field_offset = offsetof(struct elantech_data, _name),	\
1115 		.reg = _register,					\
1116 	};								\
1117 	PSMOUSE_DEFINE_ATTR(_name, S_IWUSR | S_IRUGO,			\
1118 			    &elantech_attr_##_name,			\
1119 			    elantech_show_int_attr,			\
1120 			    elantech_set_int_attr)
1121 
1122 ELANTECH_INT_ATTR(reg_07, 0x07);
1123 ELANTECH_INT_ATTR(reg_10, 0x10);
1124 ELANTECH_INT_ATTR(reg_11, 0x11);
1125 ELANTECH_INT_ATTR(reg_20, 0x20);
1126 ELANTECH_INT_ATTR(reg_21, 0x21);
1127 ELANTECH_INT_ATTR(reg_22, 0x22);
1128 ELANTECH_INT_ATTR(reg_23, 0x23);
1129 ELANTECH_INT_ATTR(reg_24, 0x24);
1130 ELANTECH_INT_ATTR(reg_25, 0x25);
1131 ELANTECH_INT_ATTR(reg_26, 0x26);
1132 ELANTECH_INT_ATTR(debug, 0);
1133 ELANTECH_INT_ATTR(paritycheck, 0);
1134 
1135 static struct attribute *elantech_attrs[] = {
1136 	&psmouse_attr_reg_07.dattr.attr,
1137 	&psmouse_attr_reg_10.dattr.attr,
1138 	&psmouse_attr_reg_11.dattr.attr,
1139 	&psmouse_attr_reg_20.dattr.attr,
1140 	&psmouse_attr_reg_21.dattr.attr,
1141 	&psmouse_attr_reg_22.dattr.attr,
1142 	&psmouse_attr_reg_23.dattr.attr,
1143 	&psmouse_attr_reg_24.dattr.attr,
1144 	&psmouse_attr_reg_25.dattr.attr,
1145 	&psmouse_attr_reg_26.dattr.attr,
1146 	&psmouse_attr_debug.dattr.attr,
1147 	&psmouse_attr_paritycheck.dattr.attr,
1148 	NULL
1149 };
1150 
1151 static struct attribute_group elantech_attr_group = {
1152 	.attrs = elantech_attrs,
1153 };
1154 
1155 static bool elantech_is_signature_valid(const unsigned char *param)
1156 {
1157 	static const unsigned char rates[] = { 200, 100, 80, 60, 40, 20, 10 };
1158 	int i;
1159 
1160 	if (param[0] == 0)
1161 		return false;
1162 
1163 	if (param[1] == 0)
1164 		return true;
1165 
1166 	for (i = 0; i < ARRAY_SIZE(rates); i++)
1167 		if (param[2] == rates[i])
1168 			return false;
1169 
1170 	return true;
1171 }
1172 
1173 /*
1174  * Use magic knock to detect Elantech touchpad
1175  */
1176 int elantech_detect(struct psmouse *psmouse, bool set_properties)
1177 {
1178 	struct ps2dev *ps2dev = &psmouse->ps2dev;
1179 	unsigned char param[3];
1180 
1181 	ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_RESET_DIS);
1182 
1183 	if (ps2_command(ps2dev,  NULL, PSMOUSE_CMD_DISABLE) ||
1184 	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
1185 	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
1186 	    ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
1187 	    ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO)) {
1188 		psmouse_dbg(psmouse, "sending Elantech magic knock failed.\n");
1189 		return -1;
1190 	}
1191 
1192 	/*
1193 	 * Report this in case there are Elantech models that use a different
1194 	 * set of magic numbers
1195 	 */
1196 	if (param[0] != 0x3c || param[1] != 0x03 ||
1197 	    (param[2] != 0xc8 && param[2] != 0x00)) {
1198 		psmouse_dbg(psmouse,
1199 			    "unexpected magic knock result 0x%02x, 0x%02x, 0x%02x.\n",
1200 			    param[0], param[1], param[2]);
1201 		return -1;
1202 	}
1203 
1204 	/*
1205 	 * Query touchpad's firmware version and see if it reports known
1206 	 * value to avoid mis-detection. Logitech mice are known to respond
1207 	 * to Elantech magic knock and there might be more.
1208 	 */
1209 	if (synaptics_send_cmd(psmouse, ETP_FW_VERSION_QUERY, param)) {
1210 		psmouse_dbg(psmouse, "failed to query firmware version.\n");
1211 		return -1;
1212 	}
1213 
1214 	psmouse_dbg(psmouse,
1215 		    "Elantech version query result 0x%02x, 0x%02x, 0x%02x.\n",
1216 		    param[0], param[1], param[2]);
1217 
1218 	if (!elantech_is_signature_valid(param)) {
1219 		psmouse_dbg(psmouse,
1220 			    "Probably not a real Elantech touchpad. Aborting.\n");
1221 		return -1;
1222 	}
1223 
1224 	if (set_properties) {
1225 		psmouse->vendor = "Elantech";
1226 		psmouse->name = "Touchpad";
1227 	}
1228 
1229 	return 0;
1230 }
1231 
1232 /*
1233  * Clean up sysfs entries when disconnecting
1234  */
1235 static void elantech_disconnect(struct psmouse *psmouse)
1236 {
1237 	sysfs_remove_group(&psmouse->ps2dev.serio->dev.kobj,
1238 			   &elantech_attr_group);
1239 	kfree(psmouse->private);
1240 	psmouse->private = NULL;
1241 }
1242 
1243 /*
1244  * Put the touchpad back into absolute mode when reconnecting
1245  */
1246 static int elantech_reconnect(struct psmouse *psmouse)
1247 {
1248 	if (elantech_detect(psmouse, 0))
1249 		return -1;
1250 
1251 	if (elantech_set_absolute_mode(psmouse)) {
1252 		psmouse_err(psmouse,
1253 			    "failed to put touchpad back into absolute mode.\n");
1254 		return -1;
1255 	}
1256 
1257 	return 0;
1258 }
1259 
1260 /*
1261  * determine hardware version and set some properties according to it.
1262  */
1263 static int elantech_set_properties(struct elantech_data *etd)
1264 {
1265 	/* This represents the version of IC body. */
1266 	int ver = (etd->fw_version & 0x0f0000) >> 16;
1267 
1268 	/* Early version of Elan touchpads doesn't obey the rule. */
1269 	if (etd->fw_version < 0x020030 || etd->fw_version == 0x020600)
1270 		etd->hw_version = 1;
1271 	else {
1272 		switch (ver) {
1273 		case 2:
1274 		case 4:
1275 			etd->hw_version = 2;
1276 			break;
1277 		case 5:
1278 			etd->hw_version = 3;
1279 			break;
1280 		case 6:
1281 			etd->hw_version = 4;
1282 			break;
1283 		default:
1284 			return -1;
1285 		}
1286 	}
1287 
1288 	/* decide which send_cmd we're gonna use early */
1289 	etd->send_cmd = etd->hw_version >= 3 ? elantech_send_cmd :
1290 					       synaptics_send_cmd;
1291 
1292 	/* Turn on packet checking by default */
1293 	etd->paritycheck = 1;
1294 
1295 	/*
1296 	 * This firmware suffers from misreporting coordinates when
1297 	 * a touch action starts causing the mouse cursor or scrolled page
1298 	 * to jump. Enable a workaround.
1299 	 */
1300 	etd->jumpy_cursor =
1301 		(etd->fw_version == 0x020022 || etd->fw_version == 0x020600);
1302 
1303 	if (etd->hw_version > 1) {
1304 		/* For now show extra debug information */
1305 		etd->debug = 1;
1306 
1307 		if (etd->fw_version >= 0x020800)
1308 			etd->reports_pressure = true;
1309 	}
1310 
1311 	return 0;
1312 }
1313 
1314 /*
1315  * Initialize the touchpad and create sysfs entries
1316  */
1317 int elantech_init(struct psmouse *psmouse)
1318 {
1319 	struct elantech_data *etd;
1320 	int i, error;
1321 	unsigned char param[3];
1322 
1323 	psmouse->private = etd = kzalloc(sizeof(struct elantech_data), GFP_KERNEL);
1324 	if (!etd)
1325 		return -ENOMEM;
1326 
1327 	etd->parity[0] = 1;
1328 	for (i = 1; i < 256; i++)
1329 		etd->parity[i] = etd->parity[i & (i - 1)] ^ 1;
1330 
1331 	/*
1332 	 * Do the version query again so we can store the result
1333 	 */
1334 	if (synaptics_send_cmd(psmouse, ETP_FW_VERSION_QUERY, param)) {
1335 		psmouse_err(psmouse, "failed to query firmware version.\n");
1336 		goto init_fail;
1337 	}
1338 	etd->fw_version = (param[0] << 16) | (param[1] << 8) | param[2];
1339 
1340 	if (elantech_set_properties(etd)) {
1341 		psmouse_err(psmouse, "unknown hardware version, aborting...\n");
1342 		goto init_fail;
1343 	}
1344 	psmouse_info(psmouse,
1345 		     "assuming hardware version %d (with firmware version 0x%02x%02x%02x)\n",
1346 		     etd->hw_version, param[0], param[1], param[2]);
1347 
1348 	if (etd->send_cmd(psmouse, ETP_CAPABILITIES_QUERY,
1349 	    etd->capabilities)) {
1350 		psmouse_err(psmouse, "failed to query capabilities.\n");
1351 		goto init_fail;
1352 	}
1353 	psmouse_info(psmouse,
1354 		     "Synaptics capabilities query result 0x%02x, 0x%02x, 0x%02x.\n",
1355 		     etd->capabilities[0], etd->capabilities[1],
1356 		     etd->capabilities[2]);
1357 
1358 	if (elantech_set_absolute_mode(psmouse)) {
1359 		psmouse_err(psmouse,
1360 			    "failed to put touchpad into absolute mode.\n");
1361 		goto init_fail;
1362 	}
1363 
1364 	if (elantech_set_input_params(psmouse)) {
1365 		psmouse_err(psmouse, "failed to query touchpad range.\n");
1366 		goto init_fail;
1367 	}
1368 
1369 	error = sysfs_create_group(&psmouse->ps2dev.serio->dev.kobj,
1370 				   &elantech_attr_group);
1371 	if (error) {
1372 		psmouse_err(psmouse,
1373 			    "failed to create sysfs attributes, error: %d.\n",
1374 			    error);
1375 		goto init_fail;
1376 	}
1377 
1378 	psmouse->protocol_handler = elantech_process_byte;
1379 	psmouse->disconnect = elantech_disconnect;
1380 	psmouse->reconnect = elantech_reconnect;
1381 	psmouse->pktsize = etd->hw_version > 1 ? 6 : 4;
1382 
1383 	return 0;
1384 
1385  init_fail:
1386 	kfree(etd);
1387 	return -1;
1388 }
1389