path: root/Documentation
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authorLinus Torvalds <torvalds@linux-foundation.org>2013-03-11 07:49:37 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-03-11 07:49:37 -0700
commit152fcb2784c9305e19e7caee2932b9e32b0a1d41 (patch)
treea8fceed3656ea2e7ef6a3c2f5afb450cf7620bdd /Documentation
parentLinux 3.9-rc2 (diff)
parentInput: mms114 - Fix regulator enable and disable paths (diff)
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
Pull input updates from Dmitry Torokhov: "Except for the largish change to the ALPS driver adding "Dolphin V1" support and Wacom getting a new signature of yet another device, the rest are straightforward driver fixes." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: Input: mms114 - Fix regulator enable and disable paths Input: ads7864 - check return value of regulator enable Input: tc3589x-keypad - fix keymap size Input: wacom - add support for 0x10d Input: ALPS - update documentation for recent touchpad driver mods Input: ALPS - add "Dolphin V1" touchpad support Input: ALPS - remove unused argument to alps_enter_command_mode() Input: cypress_ps2 - fix trackpadi found in Dell XPS12
Diffstat (limited to 'Documentation')
1 files changed, 60 insertions, 7 deletions
diff --git a/Documentation/input/alps.txt b/Documentation/input/alps.txt
index 3262b6e4d686..e544c7ff8cfa 100644
--- a/Documentation/input/alps.txt
+++ b/Documentation/input/alps.txt
@@ -3,10 +3,26 @@ ALPS Touchpad Protocol
-Currently the ALPS touchpad driver supports four protocol versions in use by
-ALPS touchpads, called versions 1, 2, 3, and 4. Information about the various
-protocol versions is contained in the following sections.
+Currently the ALPS touchpad driver supports five protocol versions in use by
+ALPS touchpads, called versions 1, 2, 3, 4 and 5.
+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.
@@ -20,9 +36,13 @@ 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.
-With 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.
+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
@@ -47,6 +67,14 @@ 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
@@ -187,3 +215,28 @@ There are several things worth noting here.
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