About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Documentation / input / elantech.txt




Custom Search

Based on kernel version 4.0. Page generated on 2015-04-14 21:24 EST.

1	Elantech Touchpad Driver
2	========================
3	
4		Copyright (C) 2007-2008 Arjan Opmeer <arjan@opmeer.net>
5	
6		Extra information for hardware version 1 found and
7		provided by Steve Havelka
8	
9		Version 2 (EeePC) hardware support based on patches
10		received from Woody at Xandros and forwarded to me
11		by user StewieGriffin at the eeeuser.com forum
12	
13	
14	Contents
15	~~~~~~~~
16	
17	 1. Introduction
18	 2. Extra knobs
19	 3. Differentiating hardware versions
20	 4. Hardware version 1
21	    4.1 Registers
22	    4.2 Native relative mode 4 byte packet format
23	    4.3 Native absolute mode 4 byte packet format
24	 5. Hardware version 2
25	    5.1 Registers
26	    5.2 Native absolute mode 6 byte packet format
27	        5.2.1 Parity checking and packet re-synchronization
28	        5.2.2 One/Three finger touch
29	        5.2.3 Two finger touch
30	 6. Hardware version 3
31	    6.1 Registers
32	    6.2 Native absolute mode 6 byte packet format
33	        6.2.1 One/Three finger touch
34	        6.2.2 Two finger touch
35	 7. Hardware version 4
36	    7.1 Registers
37	    7.2 Native absolute mode 6 byte packet format
38	        7.2.1 Status packet
39	        7.2.2 Head packet
40	        7.2.3 Motion packet
41	 8. Trackpoint (for Hardware version 3 and 4)
42	    8.1 Registers
43	    8.2 Native relative mode 6 byte packet format
44	        8.2.1 Status Packet
45	
46	
47	
48	1. Introduction
49	   ~~~~~~~~~~~~
50	
51	Currently the Linux Elantech touchpad driver is aware of four different
52	hardware versions unimaginatively called version 1,version 2, version 3
53	and version 4. Version 1 is found in "older" laptops and uses 4 bytes per
54	packet. Version 2 seems to be introduced with the EeePC and uses 6 bytes
55	per packet, and provides additional features such as position of two fingers,
56	and width of the touch.  Hardware version 3 uses 6 bytes per packet (and
57	for 2 fingers the concatenation of two 6 bytes packets) and allows tracking
58	of up to 3 fingers. Hardware version 4 uses 6 bytes per packet, and can
59	combine a status packet with multiple head or motion packets. Hardware version
60	4 allows tracking up to 5 fingers.
61	
62	Some Hardware version 3 and version 4 also have a trackpoint which uses a
63	separate packet format. It is also 6 bytes per packet.
64	
65	The driver tries to support both hardware versions and should be compatible
66	with the Xorg Synaptics touchpad driver and its graphical configuration
67	utilities.
68	
69	Note that a mouse button is also associated with either the touchpad or the
70	trackpoint when a trackpoint is available.  Disabling the Touchpad in xorg
71	(TouchPadOff=0) will also disable the buttons associated with the touchpad.
72	
73	Additionally the operation of the touchpad can be altered by adjusting the
74	contents of some of its internal registers. These registers are represented
75	by the driver as sysfs entries under /sys/bus/serio/drivers/psmouse/serio?
76	that can be read from and written to.
77	
78	Currently only the registers for hardware version 1 are somewhat understood.
79	Hardware version 2 seems to use some of the same registers but it is not
80	known whether the bits in the registers represent the same thing or might
81	have changed their meaning.
82	
83	On top of that, some register settings have effect only when the touchpad is
84	in relative mode and not in absolute mode. As the Linux Elantech touchpad
85	driver always puts the hardware into absolute mode not all information
86	mentioned below can be used immediately. But because there is no freely
87	available Elantech documentation the information is provided here anyway for
88	completeness sake.
89	
90	
91	/////////////////////////////////////////////////////////////////////////////
92	
93	
94	2. Extra knobs
95	   ~~~~~~~~~~~
96	
97	Currently the Linux Elantech touchpad driver provides three extra knobs under
98	/sys/bus/serio/drivers/psmouse/serio? for the user.
99	
100	* debug
101	
102	   Turn different levels of debugging ON or OFF.
103	
104	   By echoing "0" to this file all debugging will be turned OFF.
105	
106	   Currently a value of "1" will turn on some basic debugging and a value of
107	   "2" will turn on packet debugging. For hardware version 1 the default is
108	   OFF. For version 2 the default is "1".
109	
110	   Turning packet debugging on will make the driver dump every packet
111	   received to the syslog before processing it. Be warned that this can
112	   generate quite a lot of data!
113	
114	* paritycheck
115	
116	   Turns parity checking ON or OFF.
117	
118	   By echoing "0" to this file parity checking will be turned OFF. Any
119	   non-zero value will turn it ON. For hardware version 1 the default is ON.
120	   For version 2 the default it is OFF.
121	
122	   Hardware version 1 provides basic data integrity verification by
123	   calculating a parity bit for the last 3 bytes of each packet. The driver
124	   can check these bits and reject any packet that appears corrupted. Using
125	   this knob you can bypass that check.
126	
127	   Hardware version 2 does not provide the same parity bits. Only some basic
128	   data consistency checking can be done. For now checking is disabled by
129	   default. Currently even turning it on will do nothing.
130	
131	* crc_enabled
132	
133	   Sets crc_enabled to 0/1. The name "crc_enabled" is the official name of
134	   this integrity check, even though it is not an actual cyclic redundancy
135	   check.
136	
137	   Depending on the state of crc_enabled, certain basic data integrity
138	   verification is done by the driver on hardware version 3 and 4. The
139	   driver will reject any packet that appears corrupted. Using this knob,
140	   The state of crc_enabled can be altered with this knob.
141	
142	   Reading the crc_enabled value will show the active value. Echoing
143	   "0" or "1" to this file will set the state to "0" or "1".
144	
145	/////////////////////////////////////////////////////////////////////////////
146	
147	3. Differentiating hardware versions
148	   =================================
149	
150	To detect the hardware version, read the version number as param[0].param[1].param[2]
151	
152	 4 bytes version: (after the arrow is the name given in the Dell-provided driver)
153	 02.00.22 => EF013
154	 02.06.00 => EF019
155	In the wild, there appear to be more versions, such as 00.01.64, 01.00.21,
156	02.00.00, 02.00.04, 02.00.06.
157	
158	 6 bytes:
159	 02.00.30 => EF113
160	 02.08.00 => EF023
161	 02.08.XX => EF123
162	 02.0B.00 => EF215
163	 04.01.XX => Scroll_EF051
164	 04.02.XX => EF051
165	In the wild, there appear to be more versions, such as 04.03.01, 04.04.11. There
166	appears to be almost no difference, except for EF113, which does not report
167	pressure/width and has different data consistency checks.
168	
169	Probably all the versions with param[0] <= 01 can be considered as
170	4 bytes/firmware 1. The versions < 02.08.00, with the exception of 02.00.30, as
171	4 bytes/firmware 2. Everything >= 02.08.00 can be considered as 6 bytes.
172	
173	/////////////////////////////////////////////////////////////////////////////
174	
175	4. Hardware version 1
176	   ==================
177	
178	4.1 Registers
179	    ~~~~~~~~~
180	
181	By echoing a hexadecimal value to a register it contents can be altered.
182	
183	For example:
184	
185	   echo -n 0x16 > reg_10
186	
187	* reg_10
188	
189	   bit   7   6   5   4   3   2   1   0
190	         B   C   T   D   L   A   S   E
191	
192	         E: 1 = enable smart edges unconditionally
193	         S: 1 = enable smart edges only when dragging
194	         A: 1 = absolute mode (needs 4 byte packets, see reg_11)
195	         L: 1 = enable drag lock (see reg_22)
196	         D: 1 = disable dynamic resolution
197	         T: 1 = disable tapping
198	         C: 1 = enable corner tap
199	         B: 1 = swap left and right button
200	
201	* reg_11
202	
203	   bit   7   6   5   4   3   2   1   0
204	         1   0   0   H   V   1   F   P
205	
206	         P: 1 = enable parity checking for relative mode
207	         F: 1 = enable native 4 byte packet mode
208	         V: 1 = enable vertical scroll area
209	         H: 1 = enable horizontal scroll area
210	
211	* reg_20
212	
213	         single finger width?
214	
215	* reg_21
216	
217	         scroll area width (small: 0x40 ... wide: 0xff)
218	
219	* reg_22
220	
221	         drag lock time out (short: 0x14 ... long: 0xfe;
222	                             0xff = tap again to release)
223	
224	* reg_23
225	
226	         tap make timeout?
227	
228	* reg_24
229	
230	         tap release timeout?
231	
232	* reg_25
233	
234	         smart edge cursor speed (0x02 = slow, 0x03 = medium, 0x04 = fast)
235	
236	* reg_26
237	
238	         smart edge activation area width?
239	
240	
241	4.2 Native relative mode 4 byte packet format
242	    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
243	
244	byte 0:
245	   bit   7   6   5   4   3   2   1   0
246	         c   c  p2  p1   1   M   R   L
247	
248	         L, R, M = 1 when Left, Right, Middle mouse button pressed
249	            some models have M as byte 3 odd parity bit
250	         when parity checking is enabled (reg_11, P = 1):
251	            p1..p2 = byte 1 and 2 odd parity bit
252	         c = 1 when corner tap detected
253	
254	byte 1:
255	   bit   7   6   5   4   3   2   1   0
256	        dx7 dx6 dx5 dx4 dx3 dx2 dx1 dx0
257	
258	         dx7..dx0 = x movement;   positive = right, negative = left
259	         byte 1 = 0xf0 when corner tap detected
260	
261	byte 2:
262	   bit   7   6   5   4   3   2   1   0
263	        dy7 dy6 dy5 dy4 dy3 dy2 dy1 dy0
264	
265	         dy7..dy0 = y movement;   positive = up,    negative = down
266	
267	byte 3:
268	   parity checking enabled (reg_11, P = 1):
269	
270	      bit   7   6   5   4   3   2   1   0
271	            w   h  n1  n0  ds3 ds2 ds1 ds0
272	
273	            normally:
274	               ds3..ds0 = scroll wheel amount and direction
275	                          positive = down or left
276	                          negative = up or right
277	            when corner tap detected:
278	               ds0 = 1 when top right corner tapped
279	               ds1 = 1 when bottom right corner tapped
280	               ds2 = 1 when bottom left corner tapped
281	               ds3 = 1 when top left corner tapped
282	            n1..n0 = number of fingers on touchpad
283	               only models with firmware 2.x report this, models with
284	               firmware 1.x seem to map one, two and three finger taps
285	               directly to L, M and R mouse buttons
286	            h = 1 when horizontal scroll action
287	            w = 1 when wide finger touch?
288	
289	   otherwise (reg_11, P = 0):
290	
291	      bit   7   6   5   4   3   2   1   0
292	           ds7 ds6 ds5 ds4 ds3 ds2 ds1 ds0
293	
294	            ds7..ds0 = vertical scroll amount and direction
295	                       negative = up
296	                       positive = down
297	
298	
299	4.3 Native absolute mode 4 byte packet format
300	    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
301	
302	EF013 and EF019 have a special behaviour (due to a bug in the firmware?), and
303	when 1 finger is touching, the first 2 position reports must be discarded.
304	This counting is reset whenever a different number of fingers is reported.
305	
306	byte 0:
307	   firmware version 1.x:
308	
309	      bit   7   6   5   4   3   2   1   0
310	            D   U  p1  p2   1  p3   R   L
311	
312	            L, R = 1 when Left, Right mouse button pressed
313	            p1..p3 = byte 1..3 odd parity bit
314	            D, U = 1 when rocker switch pressed Up, Down
315	
316	   firmware version 2.x:
317	
318	      bit   7   6   5   4   3   2   1   0
319	           n1  n0  p2  p1   1  p3   R   L
320	
321	            L, R = 1 when Left, Right mouse button pressed
322	            p1..p3 = byte 1..3 odd parity bit
323	            n1..n0 = number of fingers on touchpad
324	
325	byte 1:
326	   firmware version 1.x:
327	
328	      bit   7   6   5   4   3   2   1   0
329	            f   0  th  tw  x9  x8  y9  y8
330	
331	            tw = 1 when two finger touch
332	            th = 1 when three finger touch
333	            f  = 1 when finger touch
334	
335	   firmware version 2.x:
336	
337	      bit   7   6   5   4   3   2   1   0
338	            .   .   .   .  x9  x8  y9  y8
339	
340	byte 2:
341	   bit   7   6   5   4   3   2   1   0
342	        x7  x6  x5  x4  x3  x2  x1  x0
343	
344	         x9..x0 = absolute x value (horizontal)
345	
346	byte 3:
347	   bit   7   6   5   4   3   2   1   0
348	        y7  y6  y5  y4  y3  y2  y1  y0
349	
350	         y9..y0 = absolute y value (vertical)
351	
352	
353	/////////////////////////////////////////////////////////////////////////////
354	
355	
356	5. Hardware version 2
357	   ==================
358	
359	
360	5.1 Registers
361	    ~~~~~~~~~
362	
363	By echoing a hexadecimal value to a register it contents can be altered.
364	
365	For example:
366	
367	   echo -n 0x56 > reg_10
368	
369	* reg_10
370	
371	   bit   7   6   5   4   3   2   1   0
372	         0   1   0   1   0   1   D   0
373	
374	         D: 1 = enable drag and drop
375	
376	* reg_11
377	
378	   bit   7   6   5   4   3   2   1   0
379	         1   0   0   0   S   0   1   0
380	
381	         S: 1 = enable vertical scroll
382	
383	* reg_21
384	
385	         unknown (0x00)
386	
387	* reg_22
388	
389	         drag and drop release time out (short: 0x70 ... long 0x7e;
390	                                   0x7f = never i.e. tap again to release)
391	
392	
393	5.2 Native absolute mode 6 byte packet format
394	    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
395	5.2.1 Parity checking and packet re-synchronization
396	There is no parity checking, however some consistency checks can be performed.
397	
398	For instance for EF113:
399	        SA1= packet[0];
400	        A1 = packet[1];
401	        B1 = packet[2];
402	        SB1= packet[3];
403	        C1 = packet[4];
404	        D1 = packet[5];
405	        if( (((SA1 & 0x3C) != 0x3C) && ((SA1 & 0xC0) != 0x80)) || // check Byte 1
406	            (((SA1 & 0x0C) != 0x0C) && ((SA1 & 0xC0) == 0x80)) || // check Byte 1 (one finger pressed)
407	            (((SA1 & 0xC0) != 0x80) && (( A1 & 0xF0) != 0x00)) || // check Byte 2
408	            (((SB1 & 0x3E) != 0x38) && ((SA1 & 0xC0) != 0x80)) || // check Byte 4
409	            (((SB1 & 0x0E) != 0x08) && ((SA1 & 0xC0) == 0x80)) || // check Byte 4 (one finger pressed)
410	            (((SA1 & 0xC0) != 0x80) && (( C1 & 0xF0) != 0x00))  ) // check Byte 5
411			// error detected
412	
413	For all the other ones, there are just a few constant bits:
414	        if( ((packet[0] & 0x0C) != 0x04) ||
415	            ((packet[3] & 0x0f) != 0x02) )
416			// error detected
417	
418	
419	In case an error is detected, all the packets are shifted by one (and packet[0] is discarded).
420	
421	5.2.2 One/Three finger touch
422	      ~~~~~~~~~~~~~~~~
423	
424	byte 0:
425	
426	   bit   7   6   5   4   3   2   1   0
427		 n1  n0  w3  w2   .   .   R   L
428	
429	         L, R = 1 when Left, Right mouse button pressed
430	         n1..n0 = number of fingers on touchpad
431	
432	byte 1:
433	
434	   bit   7   6   5   4   3   2   1   0
435		 p7  p6  p5  p4 x11 x10 x9  x8
436	
437	byte 2:
438	
439	   bit   7   6   5   4   3   2   1   0
440		 x7  x6  x5  x4  x3  x2  x1  x0
441	
442	         x11..x0 = absolute x value (horizontal)
443	
444	byte 3:
445	
446	   bit   7   6   5   4   3   2   1   0
447		 n4  vf  w1  w0   .   .   .  b2
448	
449		 n4 = set if more than 3 fingers (only in 3 fingers mode)
450		 vf = a kind of flag ? (only on EF123, 0 when finger is over one
451		      of the buttons, 1 otherwise)
452		 w3..w0 = width of the finger touch (not EF113)
453		 b2 (on EF113 only, 0 otherwise), b2.R.L indicates one button pressed:
454			0 = none
455			1 = Left
456			2 = Right
457			3 = Middle (Left and Right)
458			4 = Forward
459			5 = Back
460			6 = Another one
461			7 = Another one
462	
463	byte 4:
464	
465	   bit   7   6   5   4   3   2   1   0
466	        p3  p1  p2  p0  y11 y10 y9  y8
467	
468		 p7..p0 = pressure (not EF113)
469	
470	byte 5:
471	
472	   bit   7   6   5   4   3   2   1   0
473	        y7  y6  y5  y4  y3  y2  y1  y0
474	
475	         y11..y0 = absolute y value (vertical)
476	
477	
478	5.2.3 Two finger touch
479	      ~~~~~~~~~~~~~~~~
480	
481	Note that the two pairs of coordinates are not exactly the coordinates of the
482	two fingers, but only the pair of the lower-left and upper-right coordinates.
483	So the actual fingers might be situated on the other diagonal of the square
484	defined by these two points.
485	
486	byte 0:
487	
488	   bit   7   6   5   4   3   2   1   0
489	        n1  n0  ay8 ax8  .   .   R   L
490	
491	         L, R = 1 when Left, Right mouse button pressed
492	         n1..n0 = number of fingers on touchpad
493	
494	byte 1:
495	
496	   bit   7   6   5   4   3   2   1   0
497	        ax7 ax6 ax5 ax4 ax3 ax2 ax1 ax0
498	
499		 ax8..ax0 = lower-left finger absolute x value
500	
501	byte 2:
502	
503	   bit   7   6   5   4   3   2   1   0
504	        ay7 ay6 ay5 ay4 ay3 ay2 ay1 ay0
505	
506		 ay8..ay0 = lower-left finger absolute y value
507	
508	byte 3:
509	
510	   bit   7   6   5   4   3   2   1   0
511	         .   .  by8 bx8  .   .   .   .
512	
513	byte 4:
514	
515	   bit   7   6   5   4   3   2   1   0
516	        bx7 bx6 bx5 bx4 bx3 bx2 bx1 bx0
517	
518	         bx8..bx0 = upper-right finger absolute x value
519	
520	byte 5:
521	
522	   bit   7   6   5   4   3   2   1   0
523	        by7 by8 by5 by4 by3 by2 by1 by0
524	
525	         by8..by0 = upper-right finger absolute y value
526	
527	/////////////////////////////////////////////////////////////////////////////
528	
529	6. Hardware version 3
530	   ==================
531	
532	6.1 Registers
533	    ~~~~~~~~~
534	* reg_10
535	
536	   bit   7   6   5   4   3   2   1   0
537	         0   0   0   0   R   F   T   A
538	
539	         A: 1 = enable absolute tracking
540	         T: 1 = enable two finger mode auto correct
541	         F: 1 = disable ABS Position Filter
542	         R: 1 = enable real hardware resolution
543	
544	6.2 Native absolute mode 6 byte packet format
545	    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
546	1 and 3 finger touch shares the same 6-byte packet format, except that
547	3 finger touch only reports the position of the center of all three fingers.
548	
549	Firmware would send 12 bytes of data for 2 finger touch.
550	
551	Note on debounce:
552	In case the box has unstable power supply or other electricity issues, or
553	when number of finger changes, F/W would send "debounce packet" to inform
554	driver that the hardware is in debounce status.
555	The debouce packet has the following signature:
556	    byte 0: 0xc4
557	    byte 1: 0xff
558	    byte 2: 0xff
559	    byte 3: 0x02
560	    byte 4: 0xff
561	    byte 5: 0xff
562	When we encounter this kind of packet, we just ignore it.
563	
564	6.2.1 One/Three finger touch
565	      ~~~~~~~~~~~~~~~~~~~~~~
566	
567	byte 0:
568	
569	   bit   7   6   5   4   3   2   1   0
570	        n1  n0  w3  w2   0   1   R   L
571	
572	        L, R = 1 when Left, Right mouse button pressed
573	        n1..n0 = number of fingers on touchpad
574	
575	byte 1:
576	
577	   bit   7   6   5   4   3   2   1   0
578	        p7  p6  p5  p4 x11 x10  x9  x8
579	
580	byte 2:
581	
582	   bit   7   6   5   4   3   2   1   0
583	        x7  x6  x5  x4  x3  x2  x1  x0
584	
585	        x11..x0 = absolute x value (horizontal)
586	
587	byte 3:
588	
589	   bit   7   6   5   4   3   2   1   0
590	         0   0  w1  w0   0   0   1   0
591	
592	         w3..w0 = width of the finger touch
593	
594	byte 4:
595	
596	   bit   7   6   5   4   3   2   1   0
597	        p3  p1  p2  p0  y11 y10 y9  y8
598	
599	        p7..p0 = pressure
600	
601	byte 5:
602	
603	   bit   7   6   5   4   3   2   1   0
604	        y7  y6  y5  y4  y3  y2  y1  y0
605	
606	        y11..y0 = absolute y value (vertical)
607	
608	6.2.2 Two finger touch
609	      ~~~~~~~~~~~~~~~~
610	
611	The packet format is exactly the same for two finger touch, except the hardware
612	sends two 6 byte packets. The first packet contains data for the first finger,
613	the second packet has data for the second finger. So for two finger touch a
614	total of 12 bytes are sent.
615	
616	/////////////////////////////////////////////////////////////////////////////
617	
618	7. Hardware version 4
619	   ==================
620	
621	7.1 Registers
622	    ~~~~~~~~~
623	* reg_07
624	
625	   bit   7   6   5   4   3   2   1   0
626	         0   0   0   0   0   0   0   A
627	
628	         A: 1 = enable absolute tracking
629	
630	7.2 Native absolute mode 6 byte packet format
631	    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
632	v4 hardware is a true multitouch touchpad, capable of tracking up to 5 fingers.
633	Unfortunately, due to PS/2's limited bandwidth, its packet format is rather
634	complex.
635	
636	Whenever the numbers or identities of the fingers changes, the hardware sends a
637	status packet to indicate how many and which fingers is on touchpad, followed by
638	head packets or motion packets. A head packet contains data of finger id, finger
639	position (absolute x, y values), width, and pressure. A motion packet contains
640	two fingers' position delta.
641	
642	For example, when status packet tells there are 2 fingers on touchpad, then we
643	can expect two following head packets. If the finger status doesn't change,
644	the following packets would be motion packets, only sending delta of finger
645	position, until we receive a status packet.
646	
647	One exception is one finger touch. when a status packet tells us there is only
648	one finger, the hardware would just send head packets afterwards.
649	
650	7.2.1 Status packet
651	      ~~~~~~~~~~~~~
652	
653	byte 0:
654	
655	   bit   7   6   5   4   3   2   1   0
656	         .   .   .   .   0   1   R   L
657	
658	         L, R = 1 when Left, Right mouse button pressed
659	
660	byte 1:
661	
662	   bit   7   6   5   4   3   2   1   0
663	         .   .   . ft4 ft3 ft2 ft1 ft0
664	
665	         ft4 ft3 ft2 ft1 ft0 ftn = 1 when finger n is on touchpad
666	
667	byte 2: not used
668	
669	byte 3:
670	
671	   bit   7   6   5   4   3   2   1   0
672	         .   .   .   1   0   0   0   0
673	
674	         constant bits
675	
676	byte 4:
677	
678	   bit   7   6   5   4   3   2   1   0
679	         p   .   .   .   .   .   .   .
680	
681	         p = 1 for palm
682	
683	byte 5: not used
684	
685	7.2.2 Head packet
686	      ~~~~~~~~~~~
687	
688	byte 0:
689	
690	   bit   7   6   5   4   3   2   1   0
691	        w3  w2  w1  w0   0   1   R   L
692	
693	        L, R = 1 when Left, Right mouse button pressed
694	        w3..w0 = finger width (spans how many trace lines)
695	
696	byte 1:
697	
698	   bit   7   6   5   4   3   2   1   0
699	        p7  p6  p5  p4 x11 x10  x9  x8
700	
701	byte 2:
702	
703	   bit   7   6   5   4   3   2   1   0
704	        x7  x6  x5  x4  x3  x2  x1  x0
705	
706	        x11..x0 = absolute x value (horizontal)
707	
708	byte 3:
709	
710	   bit   7   6   5   4   3   2   1   0
711	       id2 id1 id0   1   0   0   0   1
712	
713	       id2..id0 = finger id
714	
715	byte 4:
716	
717	   bit   7   6   5   4   3   2   1   0
718	        p3  p1  p2  p0  y11 y10 y9  y8
719	
720	        p7..p0 = pressure
721	
722	byte 5:
723	
724	   bit   7   6   5   4   3   2   1   0
725	        y7  y6  y5  y4  y3  y2  y1  y0
726	
727	        y11..y0 = absolute y value (vertical)
728	
729	7.2.3 Motion packet
730	      ~~~~~~~~~~~~~
731	
732	byte 0:
733	
734	   bit   7   6   5   4   3   2   1   0
735	       id2 id1 id0   w   0   1   R   L
736	
737	       L, R = 1 when Left, Right mouse button pressed
738	       id2..id0 = finger id
739	       w = 1 when delta overflows (> 127 or < -128), in this case
740	       firmware sends us (delta x / 5) and (delta y  / 5)
741	
742	byte 1:
743	
744	   bit   7   6   5   4   3   2   1   0
745	        x7  x6  x5  x4  x3  x2  x1  x0
746	
747	        x7..x0 = delta x (two's complement)
748	
749	byte 2:
750	
751	   bit   7   6   5   4   3   2   1   0
752	        y7  y6  y5  y4  y3  y2  y1  y0
753	
754	        y7..y0 = delta y (two's complement)
755	
756	byte 3:
757	
758	   bit   7   6   5   4   3   2   1   0
759	       id2 id1 id0   1   0   0   1   0
760	
761	       id2..id0 = finger id
762	
763	byte 4:
764	
765	   bit   7   6   5   4   3   2   1   0
766	        x7  x6  x5  x4  x3  x2  x1  x0
767	
768	        x7..x0 = delta x (two's complement)
769	
770	byte 5:
771	
772	   bit   7   6   5   4   3   2   1   0
773	        y7  y6  y5  y4  y3  y2  y1  y0
774	
775	        y7..y0 = delta y (two's complement)
776	
777	        byte 0 ~ 2 for one finger
778	        byte 3 ~ 5 for another
779	
780	
781	8. Trackpoint (for Hardware version 3 and 4)
782	   =========================================
783	8.1 Registers
784	    ~~~~~~~~~
785	No special registers have been identified.
786	
787	8.2 Native relative mode 6 byte packet format
788	    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
789	8.2.1 Status Packet
790	      ~~~~~~~~~~~~~
791	
792	byte 0:
793	   bit   7   6   5   4   3   2   1   0
794	         0   0  sx  sy   0   M   R   L
795	byte 1:
796	   bit   7   6   5   4   3   2   1   0
797	       ~sx   0   0   0   0   0   0   0
798	byte 2:
799	   bit   7   6   5   4   3   2   1   0
800	       ~sy   0   0   0   0   0   0   0
801	byte 3:
802	   bit   7   6   5   4   3   2   1   0
803	         0   0 ~sy ~sx   0   1   1   0
804	byte 4:
805	   bit   7   6   5   4   3   2   1   0
806	        x7  x6  x5  x4  x3  x2  x1  x0
807	byte 5:
808	   bit   7   6   5   4   3   2   1   0
809	        y7  y6  y5  y4  y3  y2  y1  y0
810	
811	
812	         x and y are written in two's complement spread
813	             over 9 bits with sx/sy the relative top bit and
814	             x7..x0 and y7..y0 the lower bits.
815		 ~sx is the inverse of sx, ~sy is the inverse of sy.
816	         The sign of y is opposite to what the input driver
817	             expects for a relative movement
Hide Line Numbers
About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Information is copyright its respective author. All material is available from the Linux Kernel Source distributed under a GPL License. This page is provided as a free service by mjmwired.net.