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authorAishwarya Pant <aishpant@gmail.com>2018-03-02 23:00:19 +0530
committerJonathan Corbet <corbet@lwn.net>2018-03-21 09:35:01 -0600
commitaebb47d4e7a9c5a4f456aa0b2e1f7d612d1c78ba (patch)
tree0f1e461e77e229ad08c1b190406258a0f4f3269e /Documentation/ABI
parenta10c5d91c340bc1ee09ca62949a23d8fc45e7c0a (diff)
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>
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+What: /sys/devices/platform/i8042/.../sensitivity
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) Trackpoint sensitivity.
+
+What: /sys/devices/platform/i8042/.../intertia
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) Negative inertia factor. High values cause the cursor to
+ snap backward when the trackpoint is released.
+
+What: /sys/devices/platform/i8042/.../reach
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) Backup range for z-axis press.
+
+What: /sys/devices/platform/i8042/.../draghys
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) The drag hysteresis controls how hard it is to drag with
+ z-axis pressed.
+
+What: /sys/devices/platform/i8042/.../mindrag
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) Minimum amount of force needed to trigger dragging.
+
+What: /sys/devices/platform/i8042/.../speed
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) Speed of the trackpoint cursor.
+
+What: /sys/devices/platform/i8042/.../thresh
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) Minimum value for z-axis force required to trigger a press
+ or release, relative to the running average.
+
+What: /sys/devices/platform/i8042/.../upthresh
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) The offset from the running average required to generate a
+ select (click) on z-axis on release.
+
+What: /sys/devices/platform/i8042/.../ztime
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) This attribute determines how sharp a press has to be in
+ order to be recognized.
+
+What: /sys/devices/platform/i8042/.../jenks
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) Minimum curvature in degrees required to generate a double
+ click without a release.
+
+What: /sys/devices/platform/i8042/.../skipback
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) When the skipback bit is set, backup cursor movement during
+ releases from drags will be suppressed. The default value for
+ this bit is 0.
+
+What: /sys/devices/platform/i8042/.../ext_dev
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) Disable (0) or enable (1) external pointing device.
+
+What: /sys/devices/platform/i8042/.../press_to_select
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) Writing a value of 1 to this file will enable the Press to
+ Select functions like tapping the control stick to simulate a
+ left click, and writing 0 will disable it.
+
+What: /sys/devices/platform/i8042/.../drift_time
+Date: Dec, 2014
+KernelVersion: 3.19
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) This parameter controls the period of time to test for a
+ ‘hands off’ condition (i.e. when no force is applied) before a
+ drift (noise) calibration occurs.
+
+ IBM Trackpoints have a feature to compensate for drift by
+ recalibrating themselves periodically. By default, if for 0.5
+ seconds there is no change in position, it's used as the new
+ zero. This duration is too low. Often, the calibration happens
+ when the trackpoint is in fact being used.