[PATCH v5 2/2] libcamera: software_isp: Black level from tuning file

[Milan Zamazal]

This patch allows obtaining a black level from a tuning file in addition
to the camera sensor helper.  If both of them define a black level, the
one from the tuning file takes precedence.

The use cases are:

- A user wants to use a different black level, for whatever reason.

- There is a sensor without known gains but with a known black level.
  Because a camera sensor helper cannot be defined without specifying
  gains, the only way to specify the black level is using the tuning
  file.  Software ISP uses its fallback gain handling in such a case.

Signed-off-by: Milan Zamazal <mzamazal at redhat.com>
---
 src/ipa/simple/algorithms/blc.cpp | 9 +++++++++
 src/ipa/simple/algorithms/blc.h   | 1 +
 src/ipa/simple/soft_simple.cpp    | 3 ++-
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/ipa/simple/algorithms/blc.cpp b/src/ipa/simple/algorithms/blc.cpp
index a7af2e12c..8516c4335 100644
--- a/src/ipa/simple/algorithms/blc.cpp
+++ b/src/ipa/simple/algorithms/blc.cpp
@@ -21,11 +21,20 @@ BlackLevel::BlackLevel()
 {
 }
 
+int BlackLevel::init(IPAContext &context, const YamlObject &tuningData)
+{
+	auto blackLevel = tuningData["blackLevel"].get<int16_t>();
+	if (blackLevel.has_value())
+		context.configuration.black.level = blackLevel.value() / 256;
+	return 0;
+}
+
 int BlackLevel::configure(IPAContext &context,
 			  [[maybe_unused]] const IPAConfigInfo &configInfo)
 {
 	context.activeState.blc.level =
 		context.configuration.black.level.value_or(255);
+	LOG(IPASoftBL, Info) << "pdm: blll: " << context.activeState.blc.level;
 	return 0;
 }
 
diff --git a/src/ipa/simple/algorithms/blc.h b/src/ipa/simple/algorithms/blc.h
index 828ad8b18..2cf2a8774 100644
--- a/src/ipa/simple/algorithms/blc.h
+++ b/src/ipa/simple/algorithms/blc.h
@@ -19,6 +19,7 @@ public:
 	BlackLevel();
 	~BlackLevel() = default;
 
+	int init(IPAContext &context, const YamlObject &tuningData) override;
 	int configure(IPAContext &context, const IPAConfigInfo &configInfo) override;
 	void process(IPAContext &context, const uint32_t frame,
 		     IPAFrameContext &frameContext,
diff --git a/src/ipa/simple/soft_simple.cpp b/src/ipa/simple/soft_simple.cpp
index e96e65bd1..03525b2f2 100644
--- a/src/ipa/simple/soft_simple.cpp
+++ b/src/ipa/simple/soft_simple.cpp
@@ -201,7 +201,8 @@ int IPASoftSimple::configure(const IPAConfigInfo &configInfo)
 			(context_.configuration.agc.againMax -
 			 context_.configuration.agc.againMin) /
 			100.0;
-		if (camHelper_->blackLevel().has_value()) {
+		if (!context_.configuration.black.level.has_value() &&
+		    camHelper_->blackLevel().has_value()) {
 			/*
 			 * The black level from camHelper_ is a 16 bit value, software ISP
 			 * works with 8 bit pixel values, both regardless of the actual
-- 
2.44.1