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Arjan Opmeer2a0bd752008-10-16 22:10:19 -04001Elantech 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
Florian Ragwitze938fbf2010-05-03 23:29:37 -0700336 . . . . . x10 x9 x8
Arjan Opmeer2a0bd752008-10-16 22:10:19 -0400337
338byte 2:
339
340 bit 7 6 5 4 3 2 1 0
341 x7 x6 x5 x4 x4 x2 x1 x0
342
Florian Ragwitze938fbf2010-05-03 23:29:37 -0700343 x10..x0 = absolute x value (horizontal)
Arjan Opmeer2a0bd752008-10-16 22:10:19 -0400344
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
Florian Ragwitze938fbf2010-05-03 23:29:37 -0700353 . . . . . . y9 y8
Arjan Opmeer2a0bd752008-10-16 22:10:19 -0400354
355byte 5:
356
357 bit 7 6 5 4 3 2 1 0
358 y7 y6 y5 y4 y3 y2 y1 y0
359
Florian Ragwitze938fbf2010-05-03 23:29:37 -0700360 y9..y0 = absolute y value (vertical)
Arjan Opmeer2a0bd752008-10-16 22:10:19 -0400361
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