Elantech Touchpad Driver ======================== Copyright (C) 2007-2008 Arjan Opmeer Extra information for hardware version 1 found and provided by Steve Havelka Version 2 (EeePC) hardware support based on patches received from Woody at Xandros and forwarded to me by user StewieGriffin at the eeeuser.com forum Contents ~~~~~~~~ 1. Introduction 2. Extra knobs 3. Differentiating hardware versions 4. Hardware version 1 4.1 Registers 4.2 Native relative mode 4 byte packet format 4.3 Native absolute mode 4 byte packet format 5. Hardware version 2 5.1 Registers 5.2 Native absolute mode 6 byte packet format 5.2.1 Parity checking and packet re-synchronization 5.2.2 One/Three finger touch 5.2.3 Two finger touch 6. Hardware version 3 6.1 Registers 6.2 Native absolute mode 6 byte packet format 6.2.1 One/Three finger touch 6.2.2 Two finger touch 1. Introduction ~~~~~~~~~~~~ Currently the Linux Elantech touchpad driver is aware of two different hardware versions unimaginatively called version 1 and version 2. Version 1 is found in "older" laptops and uses 4 bytes per packet. Version 2 seems to be introduced with the EeePC and uses 6 bytes per packet, and provides additional features such as position of two fingers, and width of the touch. The driver tries to support both hardware versions and should be compatible with the Xorg Synaptics touchpad driver and its graphical configuration utilities. Additionally the operation of the touchpad can be altered by adjusting the contents of some of its internal registers. These registers are represented by the driver as sysfs entries under /sys/bus/serio/drivers/psmouse/serio? that can be read from and written to. Currently only the registers for hardware version 1 are somewhat understood. Hardware version 2 seems to use some of the same registers but it is not known whether the bits in the registers represent the same thing or might have changed their meaning. On top of that, some register settings have effect only when the touchpad is in relative mode and not in absolute mode. As the Linux Elantech touchpad driver always puts the hardware into absolute mode not all information mentioned below can be used immediately. But because there is no freely available Elantech documentation the information is provided here anyway for completeness sake. ///////////////////////////////////////////////////////////////////////////// 2. Extra knobs ~~~~~~~~~~~ Currently the Linux Elantech touchpad driver provides two extra knobs under /sys/bus/serio/drivers/psmouse/serio? for the user. * debug Turn different levels of debugging ON or OFF. By echoing "0" to this file all debugging will be turned OFF. Currently a value of "1" will turn on some basic debugging and a value of "2" will turn on packet debugging. For hardware version 1 the default is OFF. For version 2 the default is "1". Turning packet debugging on will make the driver dump every packet received to the syslog before processing it. Be warned that this can generate quite a lot of data! * paritycheck Turns parity checking ON or OFF. By echoing "0" to this file parity checking will be turned OFF. Any non-zero value will turn it ON. For hardware version 1 the default is ON. For version 2 the default it is OFF. Hardware version 1 provides basic data integrity verification by calculating a parity bit for the last 3 bytes of each packet. The driver can check these bits and reject any packet that appears corrupted. Using this knob you can bypass that check. Hardware version 2 does not provide the same parity bits. Only some basic data consistency checking can be done. For now checking is disabled by default. Currently even turning it on will do nothing. ///////////////////////////////////////////////////////////////////////////// 3. Differentiating hardware versions ================================= To detect the hardware version, read the version number as param[0].param[1].param[2] 4 bytes version: (after the arrow is the name given in the Dell-provided driver) 02.00.22 => EF013 02.06.00 => EF019 In the wild, there appear to be more versions, such as 00.01.64, 01.00.21, 02.00.00, 02.00.04, 02.00.06. 6 bytes: 02.00.30 => EF113 02.08.00 => EF023 02.08.XX => EF123 02.0B.00 => EF215 04.01.XX => Scroll_EF051 04.02.XX => EF051 In the wild, there appear to be more versions, such as 04.03.01, 04.04.11. There appears to be almost no difference, except for EF113, which does not report pressure/width and has different data consistency checks. Probably all the versions with param[0] <= 01 can be considered as 4 bytes/firmware 1. The versions < 02.08.00, with the exception of 02.00.30, as 4 bytes/firmware 2. Everything >= 02.08.00 can be considered as 6 bytes. ///////////////////////////////////////////////////////////////////////////// 4. Hardware version 1 ================== 4.1 Registers ~~~~~~~~~ By echoing a hexadecimal value to a register it contents can be altered. For example: echo -n 0x16 > reg_10 * reg_10 bit 7 6 5 4 3 2 1 0 B C T D L A S E E: 1 = enable smart edges unconditionally S: 1 = enable smart edges only when dragging A: 1 = absolute mode (needs 4 byte packets, see reg_11) L: 1 = enable drag lock (see reg_22) D: 1 = disable dynamic resolution T: 1 = disable tapping C: 1 = enable corner tap B: 1 = swap left and right button * reg_11 bit 7 6 5 4 3 2 1 0 1 0 0 H V 1 F P P: 1 = enable parity checking for relative mode F: 1 = enable native 4 byte packet mode V: 1 = enable vertical scroll area H: 1 = enable horizontal scroll area * reg_20 single finger width? * reg_21 scroll area width (small: 0x40 ... wide: 0xff) * reg_22 drag lock time out (short: 0x14 ... long: 0xfe; 0xff = tap again to release) * reg_23 tap make timeout? * reg_24 tap release timeout? * reg_25 smart edge cursor speed (0x02 = slow, 0x03 = medium, 0x04 = fast) * reg_26 smart edge activation area width? 4.2 Native relative mode 4 byte packet format ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ byte 0: bit 7 6 5 4 3 2 1 0 c c p2 p1 1 M R L L, R, M = 1 when Left, Right, Middle mouse button pressed some models have M as byte 3 odd parity bit when parity checking is enabled (reg_11, P = 1): p1..p2 = byte 1 and 2 odd parity bit c = 1 when corner tap detected byte 1: bit 7 6 5 4 3 2 1 0 dx7 dx6 dx5 dx4 dx3 dx2 dx1 dx0 dx7..dx0 = x movement; positive = right, negative = left byte 1 = 0xf0 when corner tap detected byte 2: bit 7 6 5 4 3 2 1 0 dy7 dy6 dy5 dy4 dy3 dy2 dy1 dy0 dy7..dy0 = y movement; positive = up, negative = down byte 3: parity checking enabled (reg_11, P = 1): bit 7 6 5 4 3 2 1 0 w h n1 n0 ds3 ds2 ds1 ds0 normally: ds3..ds0 = scroll wheel amount and direction positive = down or left negative = up or right when corner tap detected: ds0 = 1 when top right corner tapped ds1 = 1 when bottom right corner tapped ds2 = 1 when bottom left corner tapped ds3 = 1 when top left corner tapped n1..n0 = number of fingers on touchpad only models with firmware 2.x report this, models with firmware 1.x seem to map one, two and three finger taps directly to L, M and R mouse buttons h = 1 when horizontal scroll action w = 1 when wide finger touch? otherwise (reg_11, P = 0): bit 7 6 5 4 3 2 1 0 ds7 ds6 ds5 ds4 ds3 ds2 ds1 ds0 ds7..ds0 = vertical scroll amount and direction negative = up positive = down 4.3 Native absolute mode 4 byte packet format ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ EF013 and EF019 have a special behaviour (due to a bug in the firmware?), and when 1 finger is touching, the first 2 position reports must be discarded. This counting is reset whenever a different number of fingers is reported. byte 0: firmware version 1.x: bit 7 6 5 4 3 2 1 0 D U p1 p2 1 p3 R L L, R = 1 when Left, Right mouse button pressed p1..p3 = byte 1..3 odd parity bit D, U = 1 when rocker switch pressed Up, Down firmware version 2.x: bit 7 6 5 4 3 2 1 0 n1 n0 p2 p1 1 p3 R L L, R = 1 when Left, Right mouse button pressed p1..p3 = byte 1..3 odd parity bit n1..n0 = number of fingers on touchpad byte 1: firmware version 1.x: bit 7 6 5 4 3 2 1 0 f 0 th tw x9 x8 y9 y8 tw = 1 when two finger touch th = 1 when three finger touch f = 1 when finger touch firmware version 2.x: bit 7 6 5 4 3 2 1 0 . . . . x9 x8 y9 y8 byte 2: bit 7 6 5 4 3 2 1 0 x7 x6 x5 x4 x3 x2 x1 x0 x9..x0 = absolute x value (horizontal) byte 3: bit 7 6 5 4 3 2 1 0 y7 y6 y5 y4 y3 y2 y1 y0 y9..y0 = absolute y value (vertical) ///////////////////////////////////////////////////////////////////////////// 5. Hardware version 2 ================== 5.1 Registers ~~~~~~~~~ By echoing a hexadecimal value to a register it contents can be altered. For example: echo -n 0x56 > reg_10 * reg_10 bit 7 6 5 4 3 2 1 0 0 1 0 1 0 1 D 0 D: 1 = enable drag and drop * reg_11 bit 7 6 5 4 3 2 1 0 1 0 0 0 S 0 1 0 S: 1 = enable vertical scroll * reg_21 unknown (0x00) * reg_22 drag and drop release time out (short: 0x70 ... long 0x7e; 0x7f = never i.e. tap again to release) 5.2 Native absolute mode 6 byte packet format ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 5.2.1 Parity checking and packet re-synchronization There is no parity checking, however some consistency checks can be performed. For instance for EF113: SA1= packet[0]; A1 = packet[1]; B1 = packet[2]; SB1= packet[3]; C1 = packet[4]; D1 = packet[5]; if( (((SA1 & 0x3C) != 0x3C) && ((SA1 & 0xC0) != 0x80)) || // check Byte 1 (((SA1 & 0x0C) != 0x0C) && ((SA1 & 0xC0) == 0x80)) || // check Byte 1 (one finger pressed) (((SA1 & 0xC0) != 0x80) && (( A1 & 0xF0) != 0x00)) || // check Byte 2 (((SB1 & 0x3E) != 0x38) && ((SA1 & 0xC0) != 0x80)) || // check Byte 4 (((SB1 & 0x0E) != 0x08) && ((SA1 & 0xC0) == 0x80)) || // check Byte 4 (one finger pressed) (((SA1 & 0xC0) != 0x80) && (( C1 & 0xF0) != 0x00)) ) // check Byte 5 // error detected For all the other ones, there are just a few constant bits: if( ((packet[0] & 0x0C) != 0x04) || ((packet[3] & 0x0f) != 0x02) ) // error detected In case an error is detected, all the packets are shifted by one (and packet[0] is discarded). 5.2.2 One/Three finger touch ~~~~~~~~~~~~~~~~ byte 0: bit 7 6 5 4 3 2 1 0 n1 n0 w3 w2 . . R L L, R = 1 when Left, Right mouse button pressed n1..n0 = number of fingers on touchpad byte 1: bit 7 6 5 4 3 2 1 0 p7 p6 p5 p4 x11 x10 x9 x8 byte 2: bit 7 6 5 4 3 2 1 0 x7 x6 x5 x4 x3 x2 x1 x0 x11..x0 = absolute x value (horizontal) byte 3: bit 7 6 5 4 3 2 1 0 n4 vf w1 w0 . . . b2 n4 = set if more than 3 fingers (only in 3 fingers mode) vf = a kind of flag ? (only on EF123, 0 when finger is over one of the buttons, 1 otherwise) w3..w0 = width of the finger touch (not EF113) b2 (on EF113 only, 0 otherwise), b2.R.L indicates one button pressed: 0 = none 1 = Left 2 = Right 3 = Middle (Left and Right) 4 = Forward 5 = Back 6 = Another one 7 = Another one byte 4: bit 7 6 5 4 3 2 1 0 p3 p1 p2 p0 y11 y10 y9 y8 p7..p0 = pressure (not EF113) byte 5: bit 7 6 5 4 3 2 1 0 y7 y6 y5 y4 y3 y2 y1 y0 y11..y0 = absolute y value (vertical) 5.2.3 Two finger touch ~~~~~~~~~~~~~~~~ Note that the two pairs of coordinates are not exactly the coordinates of the two fingers, but only the pair of the lower-left and upper-right coordinates. So the actual fingers might be situated on the other diagonal of the square defined by these two points. byte 0: bit 7 6 5 4 3 2 1 0 n1 n0 ay8 ax8 . . R L L, R = 1 when Left, Right mouse button pressed n1..n0 = number of fingers on touchpad byte 1: bit 7 6 5 4 3 2 1 0 ax7 ax6 ax5 ax4 ax3 ax2 ax1 ax0 ax8..ax0 = lower-left finger absolute x value byte 2: bit 7 6 5 4 3 2 1 0 ay7 ay6 ay5 ay4 ay3 ay2 ay1 ay0 ay8..ay0 = lower-left finger absolute y value byte 3: bit 7 6 5 4 3 2 1 0 . . by8 bx8 . . . . byte 4: bit 7 6 5 4 3 2 1 0 bx7 bx6 bx5 bx4 bx3 bx2 bx1 bx0 bx8..bx0 = upper-right finger absolute x value byte 5: bit 7 6 5 4 3 2 1 0 by7 by8 by5 by4 by3 by2 by1 by0 by8..by0 = upper-right finger absolute y value ///////////////////////////////////////////////////////////////////////////// 6. Hardware version 3 ================== 6.1 Registers ~~~~~~~~~ * reg_10 bit 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 A A: 1 = enable absolute tracking 6.2 Native absolute mode 6 byte packet format ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1 and 3 finger touch shares the same 6-byte packet format, except that 3 finger touch only reports the position of the center of all three fingers. Firmware would send 12 bytes of data for 2 finger touch. Note on debounce: In case the box has unstable power supply or other electricity issues, or when number of finger changes, F/W would send "debounce packet" to inform driver that the hardware is in debounce status. The debouce packet has the following signature: byte 0: 0xc4 byte 1: 0xff byte 2: 0xff byte 3: 0x02 byte 4: 0xff byte 5: 0xff When we encounter this kind of packet, we just ignore it. 6.2.1 One/Three finger touch ~~~~~~~~~~~~~~~~~~~~~~ byte 0: bit 7 6 5 4 3 2 1 0 n1 n0 w3 w2 0 1 R L L, R = 1 when Left, Right mouse button pressed n1..n0 = number of fingers on touchpad byte 1: bit 7 6 5 4 3 2 1 0 p7 p6 p5 p4 x11 x10 x9 x8 byte 2: bit 7 6 5 4 3 2 1 0 x7 x6 x5 x4 x3 x2 x1 x0 x11..x0 = absolute x value (horizontal) byte 3: bit 7 6 5 4 3 2 1 0 0 0 w1 w0 0 0 1 0 w3..w0 = width of the finger touch byte 4: bit 7 6 5 4 3 2 1 0 p3 p1 p2 p0 y11 y10 y9 y8 p7..p0 = pressure byte 5: bit 7 6 5 4 3 2 1 0 y7 y6 y5 y4 y3 y2 y1 y0 y11..y0 = absolute y value (vertical) 6.2.2 Two finger touch ~~~~~~~~~~~~~~~~ The packet format is exactly the same for two finger touch, except the hardware sends two 6 byte packets. The first packet contains data for the first finger, the second packet has data for the second finger. So for two finger touch a total of 12 bytes are sent.