diff options
Diffstat (limited to 'Documentation/input/alps.txt')
| -rw-r--r-- | Documentation/input/alps.txt | 319 |
1 files changed, 319 insertions, 0 deletions
diff --git a/Documentation/input/alps.txt b/Documentation/input/alps.txt new file mode 100644 index 000000000..c86f2f1ae --- /dev/null +++ b/Documentation/input/alps.txt @@ -0,0 +1,319 @@ +ALPS Touchpad Protocol +---------------------- + +Introduction +------------ +Currently the ALPS touchpad driver supports seven protocol versions in use by +ALPS touchpads, called versions 1, 2, 3, 4, 5, 6 and 7. + +Since roughly mid-2010 several new ALPS touchpads have been released and +integrated into a variety of laptops and netbooks. These new touchpads +have enough behavior differences that the alps_model_data definition +table, describing the properties of the different versions, is no longer +adequate. The design choices were to re-define the alps_model_data +table, with the risk of regression testing existing devices, or isolate +the new devices outside of the alps_model_data table. The latter design +choice was made. The new touchpad signatures are named: "Rushmore", +"Pinnacle", and "Dolphin", which you will see in the alps.c code. +For the purposes of this document, this group of ALPS touchpads will +generically be called "new ALPS touchpads". + +We experimented with probing the ACPI interface _HID (Hardware ID)/_CID +(Compatibility ID) definition as a way to uniquely identify the +different ALPS variants but there did not appear to be a 1:1 mapping. +In fact, it appeared to be an m:n mapping between the _HID and actual +hardware type. + +Detection +--------- + +All ALPS touchpads should respond to the "E6 report" command sequence: +E8-E6-E6-E6-E9. An ALPS touchpad should respond with either 00-00-0A or +00-00-64 if no buttons are pressed. The bits 0-2 of the first byte will be 1s +if some buttons are pressed. + +If the E6 report is successful, the touchpad model is identified using the "E7 +report" sequence: E8-E7-E7-E7-E9. The response is the model signature and is +matched against known models in the alps_model_data_array. + +For older touchpads supporting protocol versions 3 and 4, the E7 report +model signature is always 73-02-64. To differentiate between these +versions, the response from the "Enter Command Mode" sequence must be +inspected as described below. + +The new ALPS touchpads have an E7 signature of 73-03-50 or 73-03-0A but +seem to be better differentiated by the EC Command Mode response. + +Command Mode +------------ + +Protocol versions 3 and 4 have a command mode that is used to read and write +one-byte device registers in a 16-bit address space. The command sequence +EC-EC-EC-E9 places the device in command mode, and the device will respond +with 88-07 followed by a third byte. This third byte can be used to determine +whether the devices uses the version 3 or 4 protocol. + +To exit command mode, PSMOUSE_CMD_SETSTREAM (EA) is sent to the touchpad. + +While in command mode, register addresses can be set by first sending a +specific command, either EC for v3 devices or F5 for v4 devices. Then the +address is sent one nibble at a time, where each nibble is encoded as a +command with optional data. This encoding differs slightly between the v3 and +v4 protocols. + +Once an address has been set, the addressed register can be read by sending +PSMOUSE_CMD_GETINFO (E9). The first two bytes of the response contains the +address of the register being read, and the third contains the value of the +register. Registers are written by writing the value one nibble at a time +using the same encoding used for addresses. + +For the new ALPS touchpads, the EC command is used to enter command +mode. The response in the new ALPS touchpads is significantly different, +and more important in determining the behavior. This code has been +separated from the original alps_model_data table and put in the +alps_identify function. For example, there seem to be two hardware init +sequences for the "Dolphin" touchpads as determined by the second byte +of the EC response. + +Packet Format +------------- + +In the following tables, the following notation is used. + + CAPITALS = stick, miniscules = touchpad + +?'s can have different meanings on different models, such as wheel rotation, +extra buttons, stick buttons on a dualpoint, etc. + +PS/2 packet format +------------------ + + byte 0: 0 0 YSGN XSGN 1 M R L + byte 1: X7 X6 X5 X4 X3 X2 X1 X0 + byte 2: Y7 Y6 Y5 Y4 Y3 Y2 Y1 Y0 + +Note that the device never signals overflow condition. + +For protocol version 2 devices when the trackpoint is used, and no fingers +are on the touchpad, the M R L bits signal the combined status of both the +pointingstick and touchpad buttons. + +ALPS Absolute Mode - Protocol Version 1 +-------------------------------------- + + byte 0: 1 0 0 0 1 x9 x8 x7 + byte 1: 0 x6 x5 x4 x3 x2 x1 x0 + byte 2: 0 ? ? l r ? fin ges + byte 3: 0 ? ? ? ? y9 y8 y7 + byte 4: 0 y6 y5 y4 y3 y2 y1 y0 + byte 5: 0 z6 z5 z4 z3 z2 z1 z0 + +ALPS Absolute Mode - Protocol Version 2 +--------------------------------------- + + byte 0: 1 ? ? ? 1 PSM PSR PSL + byte 1: 0 x6 x5 x4 x3 x2 x1 x0 + byte 2: 0 x10 x9 x8 x7 ? fin ges + byte 3: 0 y9 y8 y7 1 M R L + byte 4: 0 y6 y5 y4 y3 y2 y1 y0 + byte 5: 0 z6 z5 z4 z3 z2 z1 z0 + +Protocol Version 2 DualPoint devices send standard PS/2 mouse packets for +the DualPoint Stick. For non interleaved dualpoint devices the pointingstick +buttons get reported separately in the PSM, PSR and PSL bits. + +Dualpoint device -- interleaved packet format +--------------------------------------------- + + byte 0: 1 1 0 0 1 1 1 1 + byte 1: 0 x6 x5 x4 x3 x2 x1 x0 + byte 2: 0 x10 x9 x8 x7 0 fin ges + byte 3: 0 0 YSGN XSGN 1 1 1 1 + byte 4: X7 X6 X5 X4 X3 X2 X1 X0 + byte 5: Y7 Y6 Y5 Y4 Y3 Y2 Y1 Y0 + byte 6: 0 y9 y8 y7 1 m r l + byte 7: 0 y6 y5 y4 y3 y2 y1 y0 + byte 8: 0 z6 z5 z4 z3 z2 z1 z0 + +Devices which use the interleaving format normally send standard PS/2 mouse +packets for the DualPoint Stick + ALPS Absolute Mode packets for the +touchpad, switching to the interleaved packet format when both the stick and +the touchpad are used at the same time. + +ALPS Absolute Mode - Protocol Version 3 +--------------------------------------- + +ALPS protocol version 3 has three different packet formats. The first two are +associated with touchpad events, and the third is associated with trackstick +events. + +The first type is the touchpad position packet. + + byte 0: 1 ? x1 x0 1 1 1 1 + byte 1: 0 x10 x9 x8 x7 x6 x5 x4 + byte 2: 0 y10 y9 y8 y7 y6 y5 y4 + byte 3: 0 M R L 1 m r l + byte 4: 0 mt x3 x2 y3 y2 y1 y0 + byte 5: 0 z6 z5 z4 z3 z2 z1 z0 + +Note that for some devices the trackstick buttons are reported in this packet, +and on others it is reported in the trackstick packets. + +The second packet type contains bitmaps representing the x and y axes. In the +bitmaps a given bit is set if there is a finger covering that position on the +given axis. Thus the bitmap packet can be used for low-resolution multi-touch +data, although finger tracking is not possible. This packet also encodes the +number of contacts (f1 and f0 in the table below). + + byte 0: 1 1 x1 x0 1 1 1 1 + byte 1: 0 x8 x7 x6 x5 x4 x3 x2 + byte 2: 0 y7 y6 y5 y4 y3 y2 y1 + byte 3: 0 y10 y9 y8 1 1 1 1 + byte 4: 0 x14 x13 x12 x11 x10 x9 y0 + byte 5: 0 1 ? ? ? ? f1 f0 + +This packet only appears after a position packet with the mt bit set, and +usually only appears when there are two or more contacts (although +occasionally it's seen with only a single contact). + +The final v3 packet type is the trackstick packet. + + byte 0: 1 1 x7 y7 1 1 1 1 + byte 1: 0 x6 x5 x4 x3 x2 x1 x0 + byte 2: 0 y6 y5 y4 y3 y2 y1 y0 + byte 3: 0 1 0 0 1 0 0 0 + byte 4: 0 z4 z3 z2 z1 z0 ? ? + byte 5: 0 0 1 1 1 1 1 1 + +ALPS Absolute Mode - Protocol Version 4 +--------------------------------------- + +Protocol version 4 has an 8-byte packet format. + + byte 0: 1 ? x1 x0 1 1 1 1 + byte 1: 0 x10 x9 x8 x7 x6 x5 x4 + byte 2: 0 y10 y9 y8 y7 y6 y5 y4 + byte 3: 0 1 x3 x2 y3 y2 y1 y0 + byte 4: 0 ? ? ? 1 ? r l + byte 5: 0 z6 z5 z4 z3 z2 z1 z0 + byte 6: bitmap data (described below) + byte 7: bitmap data (described below) + +The last two bytes represent a partial bitmap packet, with 3 full packets +required to construct a complete bitmap packet. Once assembled, the 6-byte +bitmap packet has the following format: + + byte 0: 0 1 x7 x6 x5 x4 x3 x2 + byte 1: 0 x1 x0 y4 y3 y2 y1 y0 + byte 2: 0 0 ? x14 x13 x12 x11 x10 + byte 3: 0 x9 x8 y9 y8 y7 y6 y5 + byte 4: 0 0 0 0 0 0 0 0 + byte 5: 0 0 0 0 0 0 0 y10 + +There are several things worth noting here. + + 1) In the bitmap data, bit 6 of byte 0 serves as a sync byte to + identify the first fragment of a bitmap packet. + + 2) The bitmaps represent the same data as in the v3 bitmap packets, although + the packet layout is different. + + 3) There doesn't seem to be a count of the contact points anywhere in the v4 + protocol packets. Deriving a count of contact points must be done by + analyzing the bitmaps. + + 4) There is a 3 to 1 ratio of position packets to bitmap packets. Therefore + MT position can only be updated for every third ST position update, and + the count of contact points can only be updated every third packet as + well. + +So far no v4 devices with tracksticks have been encountered. + +ALPS Absolute Mode - Protocol Version 5 +--------------------------------------- +This is basically Protocol Version 3 but with different logic for packet +decode. It uses the same alps_process_touchpad_packet_v3 call with a +specialized decode_fields function pointer to correctly interpret the +packets. This appears to only be used by the Dolphin devices. + +For single-touch, the 6-byte packet format is: + + byte 0: 1 1 0 0 1 0 0 0 + byte 1: 0 x6 x5 x4 x3 x2 x1 x0 + byte 2: 0 y6 y5 y4 y3 y2 y1 y0 + byte 3: 0 M R L 1 m r l + byte 4: y10 y9 y8 y7 x10 x9 x8 x7 + byte 5: 0 z6 z5 z4 z3 z2 z1 z0 + +For mt, the format is: + + byte 0: 1 1 1 n3 1 n2 n1 x24 + byte 1: 1 y7 y6 y5 y4 y3 y2 y1 + byte 2: ? x2 x1 y12 y11 y10 y9 y8 + byte 3: 0 x23 x22 x21 x20 x19 x18 x17 + byte 4: 0 x9 x8 x7 x6 x5 x4 x3 + byte 5: 0 x16 x15 x14 x13 x12 x11 x10 + +ALPS Absolute Mode - Protocol Version 6 +--------------------------------------- + +For trackstick packet, the format is: + + byte 0: 1 1 1 1 1 1 1 1 + byte 1: 0 X6 X5 X4 X3 X2 X1 X0 + byte 2: 0 Y6 Y5 Y4 Y3 Y2 Y1 Y0 + byte 3: ? Y7 X7 ? ? M R L + byte 4: Z7 Z6 Z5 Z4 Z3 Z2 Z1 Z0 + byte 5: 0 1 1 1 1 1 1 1 + +For touchpad packet, the format is: + + byte 0: 1 1 1 1 1 1 1 1 + byte 1: 0 0 0 0 x3 x2 x1 x0 + byte 2: 0 0 0 0 y3 y2 y1 y0 + byte 3: ? x7 x6 x5 x4 ? r l + byte 4: ? y7 y6 y5 y4 ? ? ? + byte 5: z7 z6 z5 z4 z3 z2 z1 z0 + +(v6 touchpad does not have middle button) + +ALPS Absolute Mode - Protocol Version 7 +--------------------------------------- + +For trackstick packet, the format is: + + byte 0: 0 1 0 0 1 0 0 0 + byte 1: 1 1 * * 1 M R L + byte 2: X7 1 X5 X4 X3 X2 X1 X0 + byte 3: Z6 1 Y6 X6 1 Y2 Y1 Y0 + byte 4: Y7 0 Y5 Y4 Y3 1 1 0 + byte 5: T&P 0 Z5 Z4 Z3 Z2 Z1 Z0 + +For touchpad packet, the format is: + + packet-fmt b7 b6 b5 b4 b3 b2 b1 b0 + byte 0: TWO & MULTI L 1 R M 1 Y0-2 Y0-1 Y0-0 + byte 0: NEW L 1 X1-5 1 1 Y0-2 Y0-1 Y0-0 + byte 1: Y0-10 Y0-9 Y0-8 Y0-7 Y0-6 Y0-5 Y0-4 Y0-3 + byte 2: X0-11 1 X0-10 X0-9 X0-8 X0-7 X0-6 X0-5 + byte 3: X1-11 1 X0-4 X0-3 1 X0-2 X0-1 X0-0 + byte 4: TWO X1-10 TWO X1-9 X1-8 X1-7 X1-6 X1-5 X1-4 + byte 4: MULTI X1-10 TWO X1-9 X1-8 X1-7 X1-6 Y1-5 1 + byte 4: NEW X1-10 TWO X1-9 X1-8 X1-7 X1-6 0 0 + byte 5: TWO & NEW Y1-10 0 Y1-9 Y1-8 Y1-7 Y1-6 Y1-5 Y1-4 + byte 5: MULTI Y1-10 0 Y1-9 Y1-8 Y1-7 Y1-6 F-1 F-0 + + L: Left button + R / M: Non-clickpads: Right / Middle button + Clickpads: When > 2 fingers are down, and some fingers + are in the button area, then the 2 coordinates reported + are for fingers outside the button area and these report + extra fingers being present in the right / left button + area. Note these fingers are not added to the F field! + so if a TWO packet is received and R = 1 then there are + 3 fingers down, etc. + TWO: 1: Two touches present, byte 0/4/5 are in TWO fmt + 0: If byte 4 bit 0 is 1, then byte 0/4/5 are in MULTI fmt + otherwise byte 0 bit 4 must be set and byte 0/4/5 are + in NEW fmt + F: Number of fingers - 3, 0 means 3 fingers, 1 means 4 ... |