Hi Tero,


I have a question. As you know, USI provides a room for vendors to 
differentiate their stylus. If a vendor wants to add reach features to 
differentiate their stylus. Do you think the vendor needs to come up 
with like HID-USI-<vendor>.c to configure the corresponding 
usages(vendor-defined data) ? or we should use other approach ? like 
register callbacks via HID-core ?

-Hyungwoo

On 11/26/21 5:01 AM, Tero Kristo wrote:

Hi,

This series is an update based on comments from Benjamin. What is done
is this series is to ditch the separate hid-driver for USI, and add the
generic support to core layers. This part basically brings the support
for providing USI events, without programmability (patches 1-6).

Additionally, a HID-BPF based sample is provided which can be used to
program / query pen parameters in comparison to the old driver level
implementation (patches 7-8, patch #8 is an incremental change on top of
patch #7 which just converts the fifo to socket so that the client can
also get results back from the server.)

The whole series is based on top of Benjamin's hid-bpf support work, and
I've pushed a branch at [1] with a series that works and brings in
the dependency. There are also a few separate patches in this series to
fix the problems I found from Benjamin's initial work for hid-bpf; I
wasn't able to get things working without those. The branch is also
based on top of 5.16-rc2 which required some extra changes to the
patches from Benjamin.

-Tero

[1] https://github.com/t-kristo/linux/tree/usi-5.16-rfc-v2-bpf