[libcamera-devel] [PATCH v4 6/6] documentation: Document vendor specific controls and properties handling
Naushir Patuck
naush at raspberrypi.com
Thu Nov 30 15:25:34 CET 2023
Add some documentation to the pipeline handler file describing how to
implement and handle vendor specific controls and properties with a
small example.
Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
---
Documentation/guides/pipeline-handler.rst | 52 +++++++++++++++++++++++
1 file changed, 52 insertions(+)
diff --git a/Documentation/guides/pipeline-handler.rst b/Documentation/guides/pipeline-handler.rst
index 66d428a19c4f..26dc93589382 100644
--- a/Documentation/guides/pipeline-handler.rst
+++ b/Documentation/guides/pipeline-handler.rst
@@ -672,6 +672,58 @@ handling controls:
#include <libcamera/controls.h>
#include <libcamera/control_ids.h>
+Vendor-specific controls and properties
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Vendor-specific controls and properties must be defined in a separate YAML file
+and included in the build by defining the pipeline handler to file mapping in
+include/libcamera/meson.build. These YAML files live in the src/libcamera
+directory.
+
+For example, adding a Raspberry Pi vendor control file for the PiSP pipeline
+handler is done with the following mapping:
+
+.. code-block:: meson
+
+ controls_map = {
+ 'controls': {
+ 'draft': 'control_ids_draft.yaml',
+ 'libcamera': 'control_ids_core.yaml',
+ 'rpi/pisp': 'control_ids_rpi.yaml',
+ },
+
+ 'properties': {
+ 'draft': 'property_ids_draft.yaml',
+ 'libcamera': 'property_ids_core.yaml',
+ }
+ }
+
+The pipeline handler named above must match the pipeline handler option string
+specified in the meson build configuration.
+
+Vendor-specific controls and properties must contain a `vendor: <vendor_string>`
+tag in the YAML file. Every unique vendor tag must define a unique and
+non-overlapping range of reserved control IDs in src/libcamera/control_ranges.yaml.
+
+For example, the following block defines a vendor-specific control with the
+`rpi` vendor tag:
+
+.. code-block:: yaml
+
+ vendor: rpi
+ controls:
+ - PispConfigDumpFile:
+ type: string
+ description: |
+ Triggers the Raspberry Pi PiSP pipeline handler to generate a JSON
+ formatted dump of the Backend configuration to the filename given by the
+ value of the control.
+
+The controls will be generated in the vendor-specific namespace
+`libcamera::controls::rpi`. Additionally a `#define
+LIBCAMERA_HAS_RPI_VENDOR_CONTROLS` will be available to allow applications to
+test for the availability of these controls.
+
Generating a default configuration
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
--
2.34.1
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