Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid

Pull HID updates from Jiri Kosina:

 - rework of generic input handling which ultimately makes the
   processing of tablet events more generic and reliable (Benjamin
   Tissoires)

 - fixes for handling unnumbered reports fully correctly in i2c-hid
   (Angela Czubak, Dmitry Torokhov)

 - untangling of intermingled code for sending and handling output
   reports in i2c-hid (Dmitry Torokhov)

 - Apple magic keyboard support improvements for newer models (José
   Expósito)

 - Apple T2 Macs support improvements (Aun-Ali Zaidi, Paul Pawlowski)

 - driver for Razer Blackwidow keyboards (Jelle van der Waa)

 - driver for SiGma Micro keyboards (Desmond Lim)

 - integration of first part of DIGImend patches in order to ultimately
   vastly improve Linux support of tablets (Nikolai Kondrashov, José
   Expósito)

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid: (55 commits)
  HID: intel-ish-hid: Use dma_alloc_coherent for firmware update
  Input: docs: add more details on the use of BTN_TOOL
  HID: input: accommodate priorities for slotted devices
  HID: input: remove the need for HID_QUIRK_INVERT
  HID: input: enforce Invert usage to be processed before InRange
  HID: core: for input reports, process the usages by priority list
  HID: compute an ordered list of input fields to process
  HID: input: move up out-of-range processing of input values
  HID: input: rework spaghetti code with switch statements
  HID: input: tag touchscreens as such if the physical is not there
  HID: core: split data fetching from processing in hid_input_field()
  HID: core: de-duplicate some code in hid_input_field()
  HID: core: statically allocate read buffers
  HID: uclogic: Support multiple frame input devices
  HID: uclogic: Define report IDs before their descriptors
  HID: uclogic: Put version first in rdesc namespace
  HID: uclogic: Use "frame" instead of "buttonpad"
  HID: uclogic: Use different constants for frame report IDs
  HID: uclogic: Specify total report size to buttonpad macro
  HID: uclogic: Switch to matching subreport bytes
  ...

1 files changed, 5 insertions, 1 deletions

diff --git a/Documentation/input/event-codes.rst b/Documentation/input/event-codes.rst
index b24ae7d292cc..8741d390b184 100644
--- a/Documentation/input/event-codes.rst
+++ b/Documentation/input/event-codes.rst
@@ -137,7 +137,11 @@ A few EV_KEY codes have special meanings:
     code should be set to a value of 1. When the tool is no longer interacting
     with the input device, the BTN_TOOL_<name> code should be reset to 0. All
     trackpads, tablets, and touchscreens should use at least one BTN_TOOL_<name>
-    code when events are generated.
+    code when events are generated. Likewise all trackpads, tablets, and
+    touchscreens should export only one BTN_TOOL_<name> at a time. To not break
+    existing userspace, it is recommended to not switch tool in one EV_SYN frame
+    but first emitting the old BTN_TOOL_<name> at 0, then emit one SYN_REPORT
+    and then set the new BTN_TOOL_<name> at 1.
 
 * BTN_TOUCH: