Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux

Input: trackpoint: document sysfs interface

Descriptions have been collected from git commit logs, code commits and
the TrackPoint System Version 4.0 Engineering Specification.

Signed-off-by: Aishwarya Pant <aishpant@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

authored by

Aishwarya Pant and committed by
Jonathan Corbet
aebb47d4 a10c5d91

+115
+115
Documentation/ABI/testing/sysfs-devices-platform-trackpoint
··· 1 + What: /sys/devices/platform/i8042/.../sensitivity 2 + Date: Aug, 2005 3 + KernelVersion: 2.6.14 4 + Contact: linux-input@vger.kernel.org 5 + Description: 6 + (RW) Trackpoint sensitivity. 7 + 8 + What: /sys/devices/platform/i8042/.../intertia 9 + Date: Aug, 2005 10 + KernelVersion: 2.6.14 11 + Contact: linux-input@vger.kernel.org 12 + Description: 13 + (RW) Negative inertia factor. High values cause the cursor to 14 + snap backward when the trackpoint is released. 15 + 16 + What: /sys/devices/platform/i8042/.../reach 17 + Date: Aug, 2005 18 + KernelVersion: 2.6.14 19 + Contact: linux-input@vger.kernel.org 20 + Description: 21 + (RW) Backup range for z-axis press. 22 + 23 + What: /sys/devices/platform/i8042/.../draghys 24 + Date: Aug, 2005 25 + KernelVersion: 2.6.14 26 + Contact: linux-input@vger.kernel.org 27 + Description: 28 + (RW) The drag hysteresis controls how hard it is to drag with 29 + z-axis pressed. 30 + 31 + What: /sys/devices/platform/i8042/.../mindrag 32 + Date: Aug, 2005 33 + KernelVersion: 2.6.14 34 + Contact: linux-input@vger.kernel.org 35 + Description: 36 + (RW) Minimum amount of force needed to trigger dragging. 37 + 38 + What: /sys/devices/platform/i8042/.../speed 39 + Date: Aug, 2005 40 + KernelVersion: 2.6.14 41 + Contact: linux-input@vger.kernel.org 42 + Description: 43 + (RW) Speed of the trackpoint cursor. 44 + 45 + What: /sys/devices/platform/i8042/.../thresh 46 + Date: Aug, 2005 47 + KernelVersion: 2.6.14 48 + Contact: linux-input@vger.kernel.org 49 + Description: 50 + (RW) Minimum value for z-axis force required to trigger a press 51 + or release, relative to the running average. 52 + 53 + What: /sys/devices/platform/i8042/.../upthresh 54 + Date: Aug, 2005 55 + KernelVersion: 2.6.14 56 + Contact: linux-input@vger.kernel.org 57 + Description: 58 + (RW) The offset from the running average required to generate a 59 + select (click) on z-axis on release. 60 + 61 + What: /sys/devices/platform/i8042/.../ztime 62 + Date: Aug, 2005 63 + KernelVersion: 2.6.14 64 + Contact: linux-input@vger.kernel.org 65 + Description: 66 + (RW) This attribute determines how sharp a press has to be in 67 + order to be recognized. 68 + 69 + What: /sys/devices/platform/i8042/.../jenks 70 + Date: Aug, 2005 71 + KernelVersion: 2.6.14 72 + Contact: linux-input@vger.kernel.org 73 + Description: 74 + (RW) Minimum curvature in degrees required to generate a double 75 + click without a release. 76 + 77 + What: /sys/devices/platform/i8042/.../skipback 78 + Date: Aug, 2005 79 + KernelVersion: 2.6.14 80 + Contact: linux-input@vger.kernel.org 81 + Description: 82 + (RW) When the skipback bit is set, backup cursor movement during 83 + releases from drags will be suppressed. The default value for 84 + this bit is 0. 85 + 86 + What: /sys/devices/platform/i8042/.../ext_dev 87 + Date: Aug, 2005 88 + KernelVersion: 2.6.14 89 + Contact: linux-input@vger.kernel.org 90 + Description: 91 + (RW) Disable (0) or enable (1) external pointing device. 92 + 93 + What: /sys/devices/platform/i8042/.../press_to_select 94 + Date: Aug, 2005 95 + KernelVersion: 2.6.14 96 + Contact: linux-input@vger.kernel.org 97 + Description: 98 + (RW) Writing a value of 1 to this file will enable the Press to 99 + Select functions like tapping the control stick to simulate a 100 + left click, and writing 0 will disable it. 101 + 102 + What: /sys/devices/platform/i8042/.../drift_time 103 + Date: Dec, 2014 104 + KernelVersion: 3.19 105 + Contact: linux-input@vger.kernel.org 106 + Description: 107 + (RW) This parameter controls the period of time to test for a 108 + ‘hands off’ condition (i.e. when no force is applied) before a 109 + drift (noise) calibration occurs. 110 + 111 + IBM Trackpoints have a feature to compensate for drift by 112 + recalibrating themselves periodically. By default, if for 0.5 113 + seconds there is no change in position, it's used as the new 114 + zero. This duration is too low. Often, the calibration happens 115 + when the trackpoint is in fact being used.