Input: alps - v7: document the v7 touchpad packet protocol

Add a table documenting where all the bits are in the v7 touchpad packets.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Hans de Goede 2014-12-18 09:54:50 -08:00 committed by Dmitry Torokhov
parent d27eb7931c
commit 27a560ba1d
1 changed files with 28 additions and 0 deletions

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@ -881,6 +881,34 @@ static void alps_get_finger_coordinate_v7(struct input_mt_pos *mt,
unsigned char *pkt,
unsigned char pkt_id)
{
/*
* packet-fmt b7 b6 b5 b4 b3 b2 b1 b0
* Byte0 TWO & MULTI L 1 R M 1 Y0-2 Y0-1 Y0-0
* Byte0 NEW L 1 X1-5 1 1 Y0-2 Y0-1 Y0-0
* Byte1 Y0-10 Y0-9 Y0-8 Y0-7 Y0-6 Y0-5 Y0-4 Y0-3
* Byte2 X0-11 1 X0-10 X0-9 X0-8 X0-7 X0-6 X0-5
* Byte3 X1-11 1 X0-4 X0-3 1 X0-2 X0-1 X0-0
* Byte4 TWO X1-10 TWO X1-9 X1-8 X1-7 X1-6 X1-5 X1-4
* Byte4 MULTI X1-10 TWO X1-9 X1-8 X1-7 X1-6 Y1-5 1
* Byte4 NEW X1-10 TWO X1-9 X1-8 X1-7 X1-6 0 0
* Byte5 TWO & NEW Y1-10 0 Y1-9 Y1-8 Y1-7 Y1-6 Y1-5 Y1-4
* Byte5 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 ...
*/
mt[0].x = ((pkt[2] & 0x80) << 4);
mt[0].x |= ((pkt[2] & 0x3F) << 5);
mt[0].x |= ((pkt[3] & 0x30) >> 1);