libcamera: controls: Auto-generate control_ids.h and control_ids.cpp

Bring back auto-generation of control ids. In this version, both the
header and the source files are generated from a single YAML file that
stores all control definitions. This allows centralising controls in a
single file, while the previous version required keeping both
declarations (in a header) and documentation (in a the source) in sync
manually.

Using YAML as a format to store control definitions is a trade-off
between ease of use (there are many YAML parsers available) and
simplicity (XML was considered, but would have lead to more complex
processing). A new build time dependency is added on python3-yaml, which
should be available as a package in all distributions and build
environments.

The YAML format is likely to change over time as we improve
documentation of controls, the first version simply copies the
information currently available. Future improvements should also include
a YAML schema to validate the YAML source file.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

1 files changed, 1 insertions, 1 deletions

diff --git a/README.rst b/README.rst
index 169837e4..2ccf7cbe 100644
--- a/README.rst
+++ b/README.rst
@@ -40,7 +40,7 @@ A C++ toolchain: [required]
 	Either {g++, clang}
 
 for libcamera: [required]
-	meson ninja-build
+	meson ninja-build python3-yaml
 
 for device hotplug enumeration: [optional]
 	pkg-config libudev-dev