3 files changed, 36 insertions, 3 deletions
diff --git a/src/ipa/rpi/controller/black_level_algorithm.h b/src/ipa/rpi/controller/black_level_algorithm.h
new file mode 100644
index 00000000..c2cff2f5
--- /dev/null
+++ b/src/ipa/rpi/controller/black_level_algorithm.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (C) 2023, Raspberry Pi Ltd
+ *
+ * black_level_algorithm.h - black level control algorithm interface
+ */
+#pragma once
+
+#include "algorithm.h"
+
+namespace RPiController {
+
+class BlackLevelAlgorithm : public Algorithm
+{
+public:
+	BlackLevelAlgorithm(Controller *controller)
+		: Algorithm(controller) {}
+	/* A black level algorithm must provide the following: */
+	virtual void initialValues(uint16_t &blackLevelR, uint16_t &blackLevelG,
+				   uint16_t &blackLevelB) = 0;
+};
+
+} /* namespace RPiController */
diff --git a/src/ipa/rpi/controller/rpi/black_level.cpp b/src/ipa/rpi/controller/rpi/black_level.cpp
index 85baec3f..2e3db51f 100644
--- a/src/ipa/rpi/controller/rpi/black_level.cpp
+++ b/src/ipa/rpi/controller/rpi/black_level.cpp
@@ -22,7 +22,7 @@ LOG_DEFINE_CATEGORY(RPiBlackLevel)
 #define NAME "rpi.black_level"
 
 BlackLevel::BlackLevel(Controller *controller)
-	: Algorithm(controller)
+	: BlackLevelAlgorithm(controller)
 {
 }
 
@@ -45,6 +45,14 @@ int BlackLevel::read(const libcamera::YamlObject &params)
 	return 0;
 }
 
+void BlackLevel::initialValues(uint16_t &blackLevelR, uint16_t &blackLevelG,
+			       uint16_t &blackLevelB)
+{
+	blackLevelR = blackLevelR_;
+	blackLevelG = blackLevelG_;
+	blackLevelB = blackLevelB_;
+}
+
 void BlackLevel::prepare(Metadata *imageMetadata)
 {
 	/*
diff --git a/src/ipa/rpi/controller/rpi/black_level.h b/src/ipa/rpi/controller/rpi/black_level.h
index 2403f7f7..d8c41c62 100644
--- a/src/ipa/rpi/controller/rpi/black_level.h
+++ b/src/ipa/rpi/controller/rpi/black_level.h
@@ -6,19 +6,21 @@
  */
 #pragma once
 
-#include "../algorithm.h"
+#include "../black_level_algorithm.h"
 #include "../black_level_status.h"
 
 /* This is our implementation of the "black level algorithm". */
 
 namespace RPiController {
 
-class BlackLevel : public Algorithm
+class BlackLevel : public BlackLevelAlgorithm
 {
 public:
 	BlackLevel(Controller *controller);
 	char const *name() const override;
 	int read(const libcamera::YamlObject &params) override;
+	void initialValues(uint16_t &blackLevelR, uint16_t &blackLevelG,
+			   uint16_t &blackLevelB) override;
 	void prepare(Metadata *imageMetadata) override;
 
 private: