[libcamera-devel] [PATCH v3 2/2] ipa: raspberrypi: 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/raspberrypi/raspberrypi.cpp | 80 +++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)

diff --git a/src/ipa/raspberrypi/raspberrypi.cpp b/src/ipa/raspberrypi/raspberrypi.cpp
index 13757955..d485b851 100644
--- a/src/ipa/raspberrypi/raspberrypi.cpp
+++ b/src/ipa/raspberrypi/raspberrypi.cpp
@@ -91,6 +91,8 @@ static 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::AwbEnable, ControlInfo(false, true) },
 	{ &controls::ColourGains, ControlInfo(0.0f, 32.0f) },
 	{ &controls::AwbMode, ControlInfo(controls::AwbModeValues) },
@@ -230,6 +232,12 @@ private:
 	/* Track the frame length times over FrameLengthsQueueSize frames. */
 	std::deque<Duration> frameLengths_;
 	Duration lastTimeout_;
+
+	/* The current state of flicker avoidance. */
+	struct FlickerState {
+		int32_t mode;
+		Duration customPeriod;
+	} flickerState_;
 };
 
 int IPARPi::init(const IPASettings &settings, bool lensPresent, IPAInitResult *result)
@@ -962,6 +970,78 @@ void IPARPi::queueRequest(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::FlickerFreq50Hz: {
+				agc->setFlickerPeriod(10000 * 1.0us);
+
+				break;
+			}
+
+			case controls::FlickerFreq60Hz: {
+				agc->setFlickerPeriod(8333.333 * 1.0us);
+
+				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: {
 			RPiController::AwbAlgorithm *awb = dynamic_cast<RPiController::AwbAlgorithm *>(
 				controller_.getAlgorithm("awb"));
-- 
2.30.2