[libcamera-devel] [PATCH v4 2/2] ipa: rpi: common: Handle AEC/AGC flicker controls

[David Plowman]

We handle the flicker modes by passing the correct period to the
AEC/AGC algorithm which already contains the necessary code.

The "Auto" mode, as well as reporting the detected flicker period via
the "AeFlickerDetected" metadata, are unsupported for now.

Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
---
 src/ipa/rpi/common/ipa_base.cpp | 64 ++++++++++++++++++++++++++++++++-
 src/ipa/rpi/common/ipa_base.h   |  6 ++++
 2 files changed, 69 insertions(+), 1 deletion(-)

diff --git a/src/ipa/rpi/common/ipa_base.cpp b/src/ipa/rpi/common/ipa_base.cpp
index f40f2e71..81d65ea5 100644
--- a/src/ipa/rpi/common/ipa_base.cpp
+++ b/src/ipa/rpi/common/ipa_base.cpp
@@ -61,6 +61,8 @@ const ControlInfoMap::Map ipaControls{
 	{ &controls::AeConstraintMode, ControlInfo(controls::AeConstraintModeValues) },
 	{ &controls::AeExposureMode, ControlInfo(controls::AeExposureModeValues) },
 	{ &controls::ExposureValue, ControlInfo(-8.0f, 8.0f, 0.0f) },
+	{ &controls::AeFlickerMode, ControlInfo(controls::AeFlickerModeValues) },
+	{ &controls::AeFlickerCustom, ControlInfo(100, 1000000) },
 	{ &controls::Brightness, ControlInfo(-1.0f, 1.0f, 0.0f) },
 	{ &controls::Contrast, ControlInfo(0.0f, 32.0f, 1.0f) },
 	{ &controls::Sharpness, ControlInfo(0.0f, 16.0f, 1.0f) },
@@ -97,7 +99,7 @@ namespace ipa::RPi {
 
 IpaBase::IpaBase()
 	: controller_(), frameCount_(0), mistrustCount_(0), lastRunTimestamp_(0),
-	  firstStart_(true)
+	  firstStart_(true), flickerState_({ 0, 0s })
 {
 }
 
@@ -812,6 +814,66 @@ void IpaBase::applyControls(const ControlList &controls)
 			break;
 		}
 
+		case controls::AE_FLICKER_MODE: {
+			RPiController::AgcAlgorithm *agc = dynamic_cast<RPiController::AgcAlgorithm *>(
+				controller_.getAlgorithm("agc"));
+			if (!agc) {
+				LOG(IPARPI, Warning)
+					<< "Could not set AeFlickerMode - no AGC algorithm";
+				break;
+			}
+
+			int32_t mode = ctrl.second.get<int32_t>();
+			bool modeValid = true;
+
+			switch (mode) {
+			case controls::FlickerOff: {
+				agc->setFlickerPeriod(0us);
+
+				break;
+			}
+
+			case controls::FlickerCustom: {
+				agc->setFlickerPeriod(flickerState_.customPeriod);
+
+				break;
+			}
+
+			default:
+				LOG(IPARPI, Error) << "Flicker mode " << mode << " is not supported";
+				modeValid = false;
+
+				break;
+			}
+
+			if (modeValid)
+				flickerState_.mode = mode;
+
+			break;
+		}
+
+		case controls::AE_FLICKER_CUSTOM: {
+			RPiController::AgcAlgorithm *agc = dynamic_cast<RPiController::AgcAlgorithm *>(
+				controller_.getAlgorithm("agc"));
+			if (!agc) {
+				LOG(IPARPI, Warning)
+					<< "Could not set AeFlickerCustom - no AGC algorithm";
+				break;
+			}
+
+			uint32_t customPeriod = ctrl.second.get<int32_t>();
+			flickerState_.customPeriod = customPeriod * 1.0us;
+
+			/*
+			 * We note that it makes no difference if the mode gets set to "custom"
+			 * first, and the period updated after, or vice versa.
+			 */
+			if (flickerState_.mode == controls::FlickerCustom)
+				agc->setFlickerPeriod(flickerState_.customPeriod);
+
+			break;
+		}
+
 		case controls::AWB_ENABLE: {
 			/* Silently ignore this control for a mono sensor. */
 			if (monoSensor_)
diff --git a/src/ipa/rpi/common/ipa_base.h b/src/ipa/rpi/common/ipa_base.h
index 39d00760..22823176 100644
--- a/src/ipa/rpi/common/ipa_base.h
+++ b/src/ipa/rpi/common/ipa_base.h
@@ -116,6 +116,12 @@ private:
 	/* Frame duration (1/fps) limits. */
 	utils::Duration minFrameDuration_;
 	utils::Duration maxFrameDuration_;
+
+	/* The current state of flicker avoidance. */
+	struct FlickerState {
+		int32_t mode;
+		utils::Duration customPeriod;
+	} flickerState_;
 };
 
 } /* namespace ipa::RPi */
-- 
2.30.2