[PATCH v4 0/3] TrackPoint doubletap enablement and user control

[Vishnu Sankar <vishnuocv@gmail.com>]

This patch series adds doubletap support for TrackPoint devices with
a clean separation of concerns:

1. Firmware enablement (trackpoint.c): Automatically enables doubletap
   on capable hardware during device detection
2. User control (thinkpad_acpi.c): Provides sysfs interface for 
   controlling event filtering

The simplified approach follows KISS principle:
- Trackpoint driver enables hardware functionality by default
- Thinkpad_acpi driver provides user control via existing filtering
- No cross-driver dependencies or complex interactions

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 simple sysfs interface for event filtering
- thinkpad_acpi.c: Uses clear naming (doubletap_filter)
- 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
- Using strstarts() instead of strcmp()
- Modified is_trackpoint_dt_capable()
- Removed _BIT suffix and used BIT() define

This version addresses the core reviewer feedback by:
- Removing dual filtering complexity
- Following KISS principle with clear separation
- Providing immediate functionality without configuration

Vishnu Sankar (3):
  input: trackpoint - Enable doubletap by default on capable devices
  platform/x86: thinkpad_acpi - Add doubletap_filter sysfs interface
  Documentation: thinkpad-acpi - Document doubletap_filter attribute

 .../admin-guide/laptops/thinkpad-acpi.rst     | 20 +++++++
 drivers/input/mouse/trackpoint.c              | 51 ++++++++++++++++++
 drivers/input/mouse/trackpoint.h              |  5 ++
 drivers/platform/x86/lenovo/thinkpad_acpi.c   | 54 +++++++++++++++++--
 4 files changed, 125 insertions(+), 5 deletions(-)

-- 
2.51.0