[PATCH 6.12 096/567] HID: input: map HID_GD_Z to ABS_DISTANCE for stylus/pen

Greg Kroah-Hartman
2026-01-06T17:19:38Z

From: Ping Cheng <pinglinux@gmail.com>

commit 7953794f741e94d30df9dafaaa4c031c85b891d6 upstream.

HID_GD_Z is mapped to ABS_Z for stylus and pen in hid-input.c. But HID_GD_Z
should be used to report ABS_DISTANCE for stylus and pen as described at:
Documentation/input/event-codes.rst#n226

* ABS_DISTANCE:

- Used to describe the distance of a tool from an interaction surface. This
event should only be emitted while the tool is hovering, meaning in close
proximity of the device and while the value of the BTN_TOUCH code is 0. If
the input device may be used freely in three dimensions, consider ABS_Z
instead.
- BTN_TOOL_<name> should be set to 1 when the tool comes into detectable
proximity and set to 0 when the tool leaves detectable proximity.
BTN_TOOL_<name> signals the type of tool that is currently detected by the
hardware and is otherwise independent of ABS_DISTANCE and/or BTN_TOUCH.

This patch makes the correct mapping. The ABS_DISTANCE is currently not mapped
by any HID usage in hid-generic driver.

Signed-off-by: Ping Cheng <ping.cheng@wacom.com>
Cc: stable@kernel.org
Signed-off-by: Jiri Kosina <jkosina@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/hid/hid-input.c | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)

--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -864,7 +864,7 @@ static void hidinput_configure_usage(str

switch (usage->hid) {
/* These usage IDs map directly to the usage codes. */
- case HID_GD_X: case HID_GD_Y: case HID_GD_Z:
+ case HID_GD_X: case HID_GD_Y:
case HID_GD_RX: case HID_GD_RY: case HID_GD_RZ:
if (field->flags & HID_MAIN_ITEM_RELATIVE)
map_rel(usage->hid & 0xf);
@@ -872,6 +872,22 @@ static void hidinput_configure_usage(str
map_abs_clear(usage->hid & 0xf);
break;

+ case HID_GD_Z:
+ /* HID_GD_Z is mapped to ABS_DISTANCE for stylus/pen */
+ if (field->flags & HID_MAIN_ITEM_RELATIVE) {
+ map_rel(usage->hid & 0xf);
+ } else {
+ if (field->application == HID_DG_PEN ||
+ field->physical == HID_DG_PEN ||
+ field->logical == HID_DG_STYLUS ||
+ field->physical == HID_DG_STYLUS ||
+ field->application == HID_DG_DIGITIZER)
+ map_abs_clear(ABS_DISTANCE);
+ else
+ map_abs_clear(usage->hid & 0xf);
+ }
+ break;
+
case HID_GD_WHEEL:
if (field->flags & HID_MAIN_ITEM_RELATIVE) {
set_bit(REL_WHEEL, input->relbit);