Re: [PATCH 12/12] Input: docs: add more details on the use of BTN_TOOL

From: Peter Hutterer
Date: Wed Feb 09 2022 - 02:21:04 EST


On Wed, Jan 26, 2022 at 05:18:32PM +0100, Benjamin Tissoires wrote:
> The HID core stack used to be very relaxed considering the BTN_TOOL_*
> usage. With the recent commits, we should now enforce to have only one
> tool at a time, meaning that we can now express that requirement in the
> docs.
>
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
> ---
> Documentation/input/event-codes.rst | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/input/event-codes.rst b/Documentation/input/event-codes.rst
> index b24ae7d292cc..41b1fa647dab 100644
> --- a/Documentation/input/event-codes.rst
> +++ b/Documentation/input/event-codes.rst
> @@ -137,7 +137,10 @@ 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. It is

s/export/set to nonzero/ to avoid any ambiguity with setting the evbit on the
device vs setting the value to nonzero.

> + however accepted to switch tool in one EV_SYN frame by setting the old
> + BTN_TOOL_<name> at a value of 0 and the new one at 1.

I would even s/accepted/recommended/ but this LGTM to me, thanks.

Acked-by: Peter Hutterer <peter.hutterer@xxxxxxxxx>

Cheers,
Peter