[PATCH v6 0/3] TrackPoint doubletap enablement and user control

[Vishnu Sankar <vishnuocv@gmail.com>]

This patch series adds support for TrackPoint doubletap with a clear and
simple separation of responsibilities between drivers:

1. Firmware enablement (trackpoint.c):
   Automatically enables doubletap on capable hardware during device
   detection.

2. User control (thinkpad_acpi.c):
   Provides a sysfs interface to enable or disable delivery of doubletap
   events to userspace.

The approach follows the KISS principle:
- The TrackPoint driver enables hardware functionality by default.
- The thinkpad_acpi driver controls whether ACPI doubletap events are
  delivered, using existing hotkey filtering infrastructure.
- No cross-driver APIs or dual filtering paths are introduced.

Changes in v6:
- Documentation: fix formatting of the doubletap_enable sysfs attribute
  description (separate "Values" list)

Changes in v5:
- Rename sysfs attribute from doubletap_filter to doubletap_enable to
  reflect actual behavior.
- Fix inverted logic so events are delivered only when doubletap is
  enabled.
- Suppress ACPI hotkey delivery instead of injecting or filtering input
  events.
- Register the sysfs attribute via hotkey_attributes[] instead of
  device_create_file().
- Drop unnecessary helper wrappers and debug logging.
- Update Documentation to reflect the new naming and semantics.

Changes in v4:
- Complete redesign based on reviewer feedback.
- trackpoint.c: Simplified to only enable doubletap by default.
- trackpoint.c: Removed all sysfs attributes and global variables.
- trackpoint.c: Uses firmware ID detection with deny list.
- thinkpad_acpi.c: Added sysfs interface for kernel-level event control.
- thinkpad_acpi.c: No cross-driver dependencies.
- Documentation: Updated to reflect simplified sysfs approach.

Changes in v3:
- No changes.

Changes in v2:
- Improved commit messages.
- Removed unnecessary comments and debug messages.
- Switched to strstarts() usage.
- Simplified firmware capability detection logic.

This version addresses the remaining review feedback by correcting the
naming and logic inversion, aligning sysfs semantics with behavior, and
fully integrating with existing thinkpad_acpi hotkey handling.

Vishnu Sankar (3):
  input: trackpoint - Enable doubletap by default on capable devices
  platform/x86: thinkpad_acpi: Add sysfs control for TrackPoint
    double-tap
  Documentation: thinkpad-acpi - Document doubletap_enable attribute

 .../admin-guide/laptops/thinkpad-acpi.rst     | 21 +++++++++
 drivers/input/mouse/trackpoint.c              | 47 +++++++++++++++++++
 drivers/input/mouse/trackpoint.h              |  5 ++
 drivers/platform/x86/lenovo/thinkpad_acpi.c   | 42 ++++++++++++++---
 4 files changed, 108 insertions(+), 7 deletions(-)

-- 
2.51.0