[PATCH v3 4/6] ipa: rkisp1: blc: Report sensor black levels in metadata

[Stefan Klug]

Add sensor black levels to the metadata of the rkisp1 pipeline.

Additionally enable raw support for this algorithm and add it to
uncalibrated.yaml, so that black levels get reported when capturing
tuning images. This is a bit of a hack, because no actual black level
correction is taking place in raw mode, but it is the easiest way to get
blacklevel reported for raw streams.

Signed-off-by: Stefan Klug <stefan.klug at ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder at ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 src/ipa/rkisp1/algorithms/blc.cpp     | 28 +++++++++++++++++++++++++++
 src/ipa/rkisp1/algorithms/blc.h       |  5 ++++-
 src/ipa/rkisp1/data/uncalibrated.yaml |  1 +
 3 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/ipa/rkisp1/algorithms/blc.cpp b/src/ipa/rkisp1/algorithms/blc.cpp
index b17b549c55df..03ec57f24be0 100644
--- a/src/ipa/rkisp1/algorithms/blc.cpp
+++ b/src/ipa/rkisp1/algorithms/blc.cpp
@@ -9,6 +9,8 @@
 
 #include <libcamera/base/log.h>
 
+#include <libcamera/control_ids.h>
+
 #include "libcamera/internal/yaml_parser.h"
 
 /**
@@ -38,6 +40,13 @@ LOG_DEFINE_CATEGORY(RkISP1Blc)
 BlackLevelCorrection::BlackLevelCorrection()
 	: tuningParameters_(false)
 {
+	/*
+	 * This is a bit of a hack. In raw mode no black level correction
+	 * happens. This flag is used to ensure the metadata gets populated with
+	 * the black level which is needed to capture proper raw images for
+	 * tuning.
+	 */
+	supportsRaw_ = true;
 }
 
 /**
@@ -107,6 +116,9 @@ void BlackLevelCorrection::prepare([[maybe_unused]] IPAContext &context,
 				   [[maybe_unused]] IPAFrameContext &frameContext,
 				   rkisp1_params_cfg *params)
 {
+	if (context.configuration.raw)
+		return;
+
 	if (frame > 0)
 		return;
 
@@ -125,6 +137,22 @@ void BlackLevelCorrection::prepare([[maybe_unused]] IPAContext &context,
 	params->module_cfg_update |= RKISP1_CIF_ISP_MODULE_BLS;
 }
 
+/**
+ * \copydoc libcamera::ipa::Algorithm::process
+ */
+void BlackLevelCorrection::process([[maybe_unused]] IPAContext &context,
+				   [[maybe_unused]] const uint32_t frame,
+				   [[maybe_unused]] IPAFrameContext &frameContext,
+				   [[maybe_unused]] const rkisp1_stat_buffer *stats,
+				   ControlList &metadata)
+{
+	metadata.set(controls::SensorBlackLevels,
+		     { static_cast<int32_t>(blackLevelRed_),
+		       static_cast<int32_t>(blackLevelGreenR_),
+		       static_cast<int32_t>(blackLevelGreenB_),
+		       static_cast<int32_t>(blackLevelBlue_) });
+}
+
 REGISTER_IPA_ALGORITHM(BlackLevelCorrection, "BlackLevelCorrection")
 
 } /* namespace ipa::rkisp1::algorithms */
diff --git a/src/ipa/rkisp1/algorithms/blc.h b/src/ipa/rkisp1/algorithms/blc.h
index 460ebcc15739..4ecac233f88b 100644
--- a/src/ipa/rkisp1/algorithms/blc.h
+++ b/src/ipa/rkisp1/algorithms/blc.h
@@ -23,7 +23,10 @@ public:
 	void prepare(IPAContext &context, const uint32_t frame,
 		     IPAFrameContext &frameContext,
 		     rkisp1_params_cfg *params) override;
-
+	void process(IPAContext &context, const uint32_t frame,
+		     IPAFrameContext &frameContext,
+		     const rkisp1_stat_buffer *stats,
+		     ControlList &metadata) override;
 private:
 	bool tuningParameters_;
 	int16_t blackLevelRed_;
diff --git a/src/ipa/rkisp1/data/uncalibrated.yaml b/src/ipa/rkisp1/data/uncalibrated.yaml
index a7bbd8d84263..609012967e02 100644
--- a/src/ipa/rkisp1/data/uncalibrated.yaml
+++ b/src/ipa/rkisp1/data/uncalibrated.yaml
@@ -5,4 +5,5 @@ version: 1
 algorithms:
   - Agc:
   - Awb:
+  - BlackLevelCorrection:
 ...
-- 
2.43.0