4 files changed, 90 insertions, 0 deletions
diff --git a/src/ipa/rkisp1/algorithms/blc.cpp b/src/ipa/rkisp1/algorithms/blc.cpp
new file mode 100644
index 00000000..0c5948ff
--- /dev/null
+++ b/src/ipa/rkisp1/algorithms/blc.cpp
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2021-2022, Ideas On Board
+ *
+ * blc.cpp - RkISP1 Black Level Correction control
+ */
+
+#include "blc.h"
+
+/**
+ * \file blc.h
+ */
+
+namespace libcamera {
+
+namespace ipa::rkisp1::algorithms {
+
+/**
+ * \class BlackLevelCorrection
+ * \brief RkISP1 Black Level Correction control
+ *
+ * The pixels output by the camera normally include a black level, because
+ * sensors do not always report a signal level of '0' for black. Pixels at or
+ * below this level should be considered black. To achieve that, the RkISP BLC
+ * algorithm subtracts a configurable offset from all pixels.
+ *
+ * The black level can be measured at runtime from an optical dark region of the
+ * camera sensor, or measured during the camera tuning process. The first option
+ * isn't currently supported.
+ */
+
+/**
+ * \copydoc libcamera::ipa::Algorithm::prepare
+ */
+void BlackLevelCorrection::prepare(IPAContext &context,
+				   rkisp1_params_cfg *params)
+{
+	if (context.frameContext.frameCount > 0)
+		return;
+	/*
+	 * Substract fixed values taken from imx219 tuning file.
+	 * \todo Use a configuration file for it ?
+	 */
+	params->others.bls_config.enable_auto = 0;
+	params->others.bls_config.fixed_val.r = 256;
+	params->others.bls_config.fixed_val.gr = 256;
+	params->others.bls_config.fixed_val.gb = 256;
+	params->others.bls_config.fixed_val.b = 256;
+
+	params->module_en_update |= RKISP1_CIF_ISP_MODULE_BLS;
+	params->module_ens |= RKISP1_CIF_ISP_MODULE_BLS;
+	params->module_cfg_update |= RKISP1_CIF_ISP_MODULE_BLS;
+}
+
+} /* namespace ipa::rkisp1::algorithms */
+
+} /* namespace libcamera */
diff --git a/src/ipa/rkisp1/algorithms/blc.h b/src/ipa/rkisp1/algorithms/blc.h
new file mode 100644
index 00000000..69874d8f
--- /dev/null
+++ b/src/ipa/rkisp1/algorithms/blc.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2021-2022, Ideas On Board
+ *
+ * blc.h - RkISP1 Black Level Correction control
+ */
+
+#pragma once
+
+#include <linux/rkisp1-config.h>
+
+#include "algorithm.h"
+
+namespace libcamera {
+
+struct IPACameraSensorInfo;
+
+namespace ipa::rkisp1::algorithms {
+
+class BlackLevelCorrection : public Algorithm
+{
+public:
+	BlackLevelCorrection() = default;
+	~BlackLevelCorrection() = default;
+
+	void prepare(IPAContext &context, rkisp1_params_cfg *params) override;
+};
+
+} /* namespace ipa::rkisp1::algorithms */
+} /* namespace libcamera */
diff --git a/src/ipa/rkisp1/algorithms/meson.build b/src/ipa/rkisp1/algorithms/meson.build
index a19c1a4f..27c97731 100644
--- a/src/ipa/rkisp1/algorithms/meson.build
+++ b/src/ipa/rkisp1/algorithms/meson.build
@@ -2,4 +2,5 @@
 
 rkisp1_ipa_algorithms = files([
     'agc.cpp',
+    'blc.cpp',
 ])
diff --git a/src/ipa/rkisp1/rkisp1.cpp b/src/ipa/rkisp1/rkisp1.cpp
index 493811d9..83ed21be 100644
--- a/src/ipa/rkisp1/rkisp1.cpp
+++ b/src/ipa/rkisp1/rkisp1.cpp
@@ -27,6 +27,7 @@
 
 #include "algorithms/agc.h"
 #include "algorithms/algorithm.h"
+#include "algorithms/blc.h"
 #include "libipa/camera_sensor_helper.h"
 
 #include "ipa_context.h"
@@ -120,6 +121,7 @@ int IPARkISP1::init(const IPASettings &settings, unsigned int hwRevision)
 
 	/* Construct our Algorithms */
 	algorithms_.push_back(std::make_unique<algorithms::Agc>());
+	algorithms_.push_back(std::make_unique<algorithms::BlackLevelCorrection>());
 
 	return 0;
 }