1Elantech 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
14Contents
15~~~~~~~~
16
17 1. Introduction
18 2. Extra knobs
19 3. Hardware version 1
20    3.1 Registers
21    3.2 Native relative mode 4 byte packet format
22    3.3 Native absolute mode 4 byte packet format
23 4. Hardware version 2
24    4.1 Registers
25    4.2 Native absolute mode 6 byte packet format
26        4.2.1 One finger touch
27        4.2.2 Two finger touch
28
29
30
311. Introduction
32   ~~~~~~~~~~~~
33
34Currently the Linux Elantech touchpad driver is aware of two different
35hardware versions unimaginatively called version 1 and version 2. Version 1
36is found in "older" laptops and uses 4 bytes per packet. Version 2 seems to
37be introduced with the EeePC and uses 6 bytes per packet.
38
39The driver tries to support both hardware versions and should be compatible
40with the Xorg Synaptics touchpad driver and its graphical configuration
41utilities.
42
43Additionally the operation of the touchpad can be altered by adjusting the
44contents of some of its internal registers. These registers are represented
45by the driver as sysfs entries under /sys/bus/serio/drivers/psmouse/serio?
46that can be read from and written to.
47
48Currently only the registers for hardware version 1 are somewhat understood.
49Hardware version 2 seems to use some of the same registers but it is not
50known whether the bits in the registers represent the same thing or might
51have changed their meaning.
52
53On top of that, some register settings have effect only when the touchpad is
54in relative mode and not in absolute mode. As the Linux Elantech touchpad
55driver always puts the hardware into absolute mode not all information
56mentioned below can be used immediately. But because there is no freely
57available Elantech documentation the information is provided here anyway for
58completeness sake.
59
60
61/////////////////////////////////////////////////////////////////////////////
62
63
642. Extra knobs
65   ~~~~~~~~~~~
66
67Currently the Linux Elantech touchpad driver provides two extra knobs under
68/sys/bus/serio/drivers/psmouse/serio? for the user.
69
70* debug
71
72   Turn different levels of debugging ON or OFF.
73
74   By echoing "0" to this file all debugging will be turned OFF.
75
76   Currently a value of "1" will turn on some basic debugging and a value of
77   "2" will turn on packet debugging. For hardware version 1 the default is
78   OFF. For version 2 the default is "1".
79
80   Turning packet debugging on will make the driver dump every packet
81   received to the syslog before processing it. Be warned that this can
82   generate quite a lot of data!
83
84* paritycheck
85
86   Turns parity checking ON or OFF.
87
88   By echoing "0" to this file parity checking will be turned OFF. Any
89   non-zero value will turn it ON. For hardware version 1 the default is ON.
90   For version 2 the default it is OFF.
91
92   Hardware version 1 provides basic data integrity verification by
93   calculating a parity bit for the last 3 bytes of each packet. The driver
94   can check these bits and reject any packet that appears corrupted. Using
95   this knob you can bypass that check.
96
97   It is not known yet whether hardware version 2 provides the same parity
98   bits. Hence checking is disabled by default. Currently even turning it on
99   will do nothing.
100
101
102/////////////////////////////////////////////////////////////////////////////
103
104
1053. Hardware version 1
106   ==================
107
1083.1 Registers
109    ~~~~~~~~~
110
111By echoing a hexadecimal value to a register it contents can be altered.
112
113For example:
114
115   echo -n 0x16 > reg_10
116
117* reg_10
118
119   bit   7   6   5   4   3   2   1   0
120         B   C   T   D   L   A   S   E
121
122         E: 1 = enable smart edges unconditionally
123         S: 1 = enable smart edges only when dragging
124         A: 1 = absolute mode (needs 4 byte packets, see reg_11)
125         L: 1 = enable drag lock (see reg_22)
126         D: 1 = disable dynamic resolution
127         T: 1 = disable tapping
128         C: 1 = enable corner tap
129         B: 1 = swap left and right button
130
131* reg_11
132
133   bit   7   6   5   4   3   2   1   0
134         1   0   0   H   V   1   F   P
135
136         P: 1 = enable parity checking for relative mode
137         F: 1 = enable native 4 byte packet mode
138         V: 1 = enable vertical scroll area
139         H: 1 = enable horizontal scroll area
140
141* reg_20
142
143         single finger width?
144
145* reg_21
146
147         scroll area width (small: 0x40 ... wide: 0xff)
148
149* reg_22
150
151         drag lock time out (short: 0x14 ... long: 0xfe;
152                             0xff = tap again to release)
153
154* reg_23
155
156         tap make timeout?
157
158* reg_24
159
160         tap release timeout?
161
162* reg_25
163
164         smart edge cursor speed (0x02 = slow, 0x03 = medium, 0x04 = fast)
165
166* reg_26
167
168         smart edge activation area width?
169
170
1713.2 Native relative mode 4 byte packet format
172    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
173
174byte 0:
175   bit   7   6   5   4   3   2   1   0
176         c   c  p2  p1   1   M   R   L
177
178         L, R, M = 1 when Left, Right, Middle mouse button pressed
179            some models have M as byte 3 odd parity bit
180         when parity checking is enabled (reg_11, P = 1):
181            p1..p2 = byte 1 and 2 odd parity bit
182         c = 1 when corner tap detected
183
184byte 1:
185   bit   7   6   5   4   3   2   1   0
186        dx7 dx6 dx5 dx4 dx3 dx2 dx1 dx0
187
188         dx7..dx0 = x movement;   positive = right, negative = left
189         byte 1 = 0xf0 when corner tap detected
190
191byte 2:
192   bit   7   6   5   4   3   2   1   0
193        dy7 dy6 dy5 dy4 dy3 dy2 dy1 dy0
194
195         dy7..dy0 = y movement;   positive = up,    negative = down
196
197byte 3:
198   parity checking enabled (reg_11, P = 1):
199
200      bit   7   6   5   4   3   2   1   0
201            w   h  n1  n0  ds3 ds2 ds1 ds0
202
203            normally:
204               ds3..ds0 = scroll wheel amount and direction
205                          positive = down or left
206                          negative = up or right
207            when corner tap detected:
208               ds0 = 1 when top right corner tapped
209               ds1 = 1 when bottom right corner tapped
210               ds2 = 1 when bottom left corner tapped
211               ds3 = 1 when top left corner tapped
212            n1..n0 = number of fingers on touchpad
213               only models with firmware 2.x report this, models with
214               firmware 1.x seem to map one, two and three finger taps
215               directly to L, M and R mouse buttons
216            h = 1 when horizontal scroll action
217            w = 1 when wide finger touch?
218
219   otherwise (reg_11, P = 0):
220
221      bit   7   6   5   4   3   2   1   0
222           ds7 ds6 ds5 ds4 ds3 ds2 ds1 ds0
223
224            ds7..ds0 = vertical scroll amount and direction
225                       negative = up
226                       positive = down
227
228
2293.3 Native absolute mode 4 byte packet format
230    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
231
232byte 0:
233   firmware version 1.x:
234
235      bit   7   6   5   4   3   2   1   0
236            D   U  p1  p2   1  p3   R   L
237
238            L, R = 1 when Left, Right mouse button pressed
239            p1..p3 = byte 1..3 odd parity bit
240            D, U = 1 when rocker switch pressed Up, Down
241
242   firmware version 2.x:
243
244      bit   7   6   5   4   3   2   1   0
245           n1  n0  p2  p1   1  p3   R   L
246
247            L, R = 1 when Left, Right mouse button pressed
248            p1..p3 = byte 1..3 odd parity bit
249            n1..n0 = number of fingers on touchpad
250
251byte 1:
252   firmware version 1.x:
253
254      bit   7   6   5   4   3   2   1   0
255            f   0  th  tw  x9  x8  y9  y8
256
257            tw = 1 when two finger touch
258            th = 1 when three finger touch
259            f  = 1 when finger touch
260
261   firmware version 2.x:
262
263      bit   7   6   5   4   3   2   1   0
264            .   .   .   .  x9  x8  y9  y8
265
266byte 2:
267   bit   7   6   5   4   3   2   1   0
268        x7  x6  x5  x4  x3  x2  x1  x0
269
270         x9..x0 = absolute x value (horizontal)
271
272byte 3:
273   bit   7   6   5   4   3   2   1   0
274        y7  y6  y5  y4  y3  y2  y1  y0
275
276         y9..y0 = absolute y value (vertical)
277
278
279/////////////////////////////////////////////////////////////////////////////
280
281
2824. Hardware version 2
283   ==================
284
285
2864.1 Registers
287    ~~~~~~~~~
288
289By echoing a hexadecimal value to a register it contents can be altered.
290
291For example:
292
293   echo -n 0x56 > reg_10
294
295* reg_10
296
297   bit   7   6   5   4   3   2   1   0
298         0   1   0   1   0   1   D   0
299
300         D: 1 = enable drag and drop
301
302* reg_11
303
304   bit   7   6   5   4   3   2   1   0
305         1   0   0   0   S   0   1   0
306
307         S: 1 = enable vertical scroll
308
309* reg_21
310
311         unknown (0x00)
312
313* reg_22
314
315         drag and drop release time out (short: 0x70 ... long 0x7e;
316                                   0x7f = never i.e. tap again to release)
317
318
3194.2 Native absolute mode 6 byte packet format
320    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
321
3224.2.1 One finger touch
323      ~~~~~~~~~~~~~~~~
324
325byte 0:
326
327   bit   7   6   5   4   3   2   1   0
328        n1  n0   .   .   .   .   R   L
329
330         L, R = 1 when Left, Right mouse button pressed
331         n1..n0 = numbers of fingers on touchpad
332
333byte 1:
334
335   bit   7   6   5   4   3   2   1   0
336         .   .   .   .   .  x10 x9  x8
337
338byte 2:
339
340   bit   7   6   5   4   3   2   1   0
341        x7  x6  x5  x4  x4  x2  x1  x0
342
343         x10..x0 = absolute x value (horizontal)
344
345byte 3:
346
347   bit   7   6   5   4   3   2   1   0
348         .   .   .   .   .   .   .   .
349
350byte 4:
351
352   bit   7   6   5   4   3   2   1   0
353         .   .   .   .   .   .  y9  y8
354
355byte 5:
356
357   bit   7   6   5   4   3   2   1   0
358        y7  y6  y5  y4  y3  y2  y1  y0
359
360         y9..y0 = absolute y value (vertical)
361
362
3634.2.2 Two finger touch
364      ~~~~~~~~~~~~~~~~
365
366byte 0:
367
368   bit   7   6   5   4   3   2   1   0
369        n1  n0  ay8 ax8  .   .   R   L
370
371         L, R = 1 when Left, Right mouse button pressed
372         n1..n0 = numbers of fingers on touchpad
373
374byte 1:
375
376   bit   7   6   5   4   3   2   1   0
377        ax7 ax6 ax5 ax4 ax3 ax2 ax1 ax0
378
379         ax8..ax0 = first finger absolute x value
380
381byte 2:
382
383   bit   7   6   5   4   3   2   1   0
384        ay7 ay6 ay5 ay4 ay3 ay2 ay1 ay0
385
386         ay8..ay0 = first finger absolute y value
387
388byte 3:
389
390   bit   7   6   5   4   3   2   1   0
391         .   .  by8 bx8  .   .   .   .
392
393byte 4:
394
395   bit   7   6   5   4   3   2   1   0
396        bx7 bx6 bx5 bx4 bx3 bx2 bx1 bx0
397
398         bx8..bx0 = second finger absolute x value
399
400byte 5:
401
402   bit   7   6   5   4   3   2   1   0
403        by7 by8 by5 by4 by3 by2 by1 by0
404
405         by8..by0 = second finger absolute y value
406