From dbf871c7a4ec1988b7963c1e49dd51e3276eedb7 Mon Sep 17 00:00:00 2001
From: Peter Hutterer <peter.hutterer@who-t.net>
Date: Wed, 5 Dec 2018 10:42:21 +1000
Subject: [PATCH] UPSTREAM: Input: add `REL_WHEEL_HI_RES` and
 `REL_HWHEEL_HI_RES`

This event code represents scroll reports from high-resolution wheels and
is modelled after the approach Windows uses. The value 120 is one detent
(wheel click) of movement. Mice with higher-resolution scrolling can send
fractions of 120 which must be accumulated in userspace. Userspace can either
wait for a full 120 to accumulate or scroll by fractions of one logical scroll
movement as the events come in. 120 was picked as magic number because it has
a high number of integer fractions that can be used by high-resolution wheels.

For more information see
https://docs.microsoft.com/en-us/previous-versions/windows/hardware/design/dn613912(v=vs.85)

These new axes obsolete REL_WHEEL and REL_HWHEEL. The legacy axes are emulated
by the kernel but the most accurate (and most granular) data is available
through the new axes.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
(am from https://patchwork.kernel.org/patch/10712855/)
(also found at https://lkml.kernel.org/r/20181205004228.10714-2-peter.hutterer@who-t.net)
(cherry picked from commit 52ea899637c746984d657b508da6e3f2686adfca)

BUG=chromium:888172
TEST=None

Change-Id: I205f0722ab9333834dbac156a0fbff244194e370
Signed-off-by: Harry Cutts <hcutts@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1465422
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Dmitry Torokhov <dtor@chromium.org>
---

diff --git a/include/uapi/linux/input-event-codes.h b/include/uapi/linux/input-event-codes.h
index 61769d4b7dbac7..3c755b6815c574 100644
--- a/include/uapi/linux/input-event-codes.h
+++ b/include/uapi/linux/input-event-codes.h
@@ -706,6 +706,8 @@
 #define REL_DIAL		0x07
 #define REL_WHEEL		0x08
 #define REL_MISC		0x09
+#define REL_WHEEL_HI_RES	0x0b
+#define REL_HWHEEL_HI_RES	0x0c
 #define REL_MAX			0x0f
 #define REL_CNT			(REL_MAX+1)
 
-- 
2.24.1.735.g03f4e72817-goog