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8a89db5187
These macros make it slightly easier and more modular to create
a HID report descriptor from scratch. Since they carry the annotation
we don't need to comment it and they cannot get stale.
For comparison, before we had this:
0x15, 0x00, // Logical Minimum (0)
0x25, 0x01, // Logical Maximum (1)
0x95, 0x04, // Report Count (4)
0x75, 0x01, // Report Size (1)
Now we can write this as:
LogicalRange_i8(0, 1)
ReportCount(4)
ReportSize(1)
Because these macros are for creating new report descriptors,
some bits aren't directly exposed. e.g in the example above:
there is a logical range as one macro that sets both min and max.
There is seldom a good use case for skipping either anyway.
These macros will need to be expanded over time.
For Usage Pages and Usage IDs, we use a tool to parse the HUT JSON
(attached to the HUT 1.5 PDF [1]) and generate all #defines for all
usage pages and usages in the form:
#define UsagePage_Foo_Bar
#define Usage_FB_SomeOrOther
Where the FB is simply the acronym based on the capital letters in the
Usage Page name or the first three letters, whichever makes slightly
more sense.
[1] https://usb.org/document-library/hid-usage-tables-15
Link: https://gitlab.freedesktop.org/libevdev/udev-hid-bpf/-/merge_requests/92
Link: https://gitlab.freedesktop.org/libevdev/udev-hid-bpf/-/merge_requests/96
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Link: https://patch.msgid.link/20240627-import-bpf-v1-1-0dbcda4a5b1f@kernel.org
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.