To circumvent a hardware issue where the touchpad is not physically
connected to the lid angle sensor, implement a notifier chain which
broadcasts lid switch events and a notifier_block which can be enabled
via a quirk to listen for those events turning the touchpad surface
on or off based on if the lid is open or closed. This will prevent
issues resulting from interference between the laptop lid and the
touchpad.

Signed-off-by: Jonathan Denose <jdenose@google.com>
---
Changes in v2:
- Remove notifier logic from input core and add lid-notifier module which exposes lid events
- Kconfig: Add CONFIG_INPUT_LID_NOTIFIER option to include lid-notifier
- Link to v1: https://lore.kernel.org/r/20251030-lid-switch-notifier-v1-0-c58dc9b1439d@google.com

---
Jonathan Denose (2):
      Input: Add lid switch notifier
      HID: multitouch: Toggle touch surface on Elan touchpad on lid event

 drivers/hid/hid-multitouch.c | 32 ++++++++++++++-
 drivers/input/Kconfig        | 11 +++++
 drivers/input/Makefile       |  1 +
 drivers/input/lid-notifier.c | 98 ++++++++++++++++++++++++++++++++++++++++++++
 include/linux/input.h        |  2 +
 5 files changed, 143 insertions(+), 1 deletion(-)
---
base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787
change-id: 20251014-lid-switch-notifier-1cb9918d675d

Best regards,
-- 
Jonathan Denose <jdenose@google.com>