From: Ping Cheng <pinglinux@gmail.com>
Date: Mon, 27 Oct 2025 20:37:42 +0000 (-0700)
Subject: HID: input: map HID_GD_Z to ABS_DISTANCE for stylus/pen
X-Git-Tag: v6.19-rc1~139^2~1^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7953794f741e94d30df9dafaaa4c031c85b891d6;p=thirdparty%2Fkernel%2Flinux.git

HID: input: map HID_GD_Z to ABS_DISTANCE for stylus/pen

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>
---

diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index 2bbb645c2ff41..32a96ae2946f1 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -878,7 +878,7 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel
 
 		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);
@@ -886,6 +886,22 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel
 				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);