[libcamera-devel] [PATCH 4/4] libcamera: ipa: raspberrypi: Populate focus FoM from the ISP statistics

[Naushir Patuck]

Switch FocusStatus::num to unsigned int for convenience.

Fill in libcamera::controls::FocusFoM with the average of the middle two
regions (across a 4x3 grid) FoM statistics from the ISP.

Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
---
 src/ipa/raspberrypi/controller/focus_status.h |  2 +-
 src/ipa/raspberrypi/raspberrypi.cpp           | 12 ++++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/ipa/raspberrypi/controller/focus_status.h b/src/ipa/raspberrypi/controller/focus_status.h
index 3ad88777..ace2fe2c 100644
--- a/src/ipa/raspberrypi/controller/focus_status.h
+++ b/src/ipa/raspberrypi/controller/focus_status.h
@@ -17,7 +17,7 @@ extern "C" {
 #endif
 
 struct FocusStatus {
-	int num;
+	unsigned int num;
 	uint32_t focus_measures[FOCUS_REGIONS];
 };
 
diff --git a/src/ipa/raspberrypi/raspberrypi.cpp b/src/ipa/raspberrypi/raspberrypi.cpp
index 62730198..b1f27861 100644
--- a/src/ipa/raspberrypi/raspberrypi.cpp
+++ b/src/ipa/raspberrypi/raspberrypi.cpp
@@ -42,6 +42,7 @@
 #include "contrast_status.h"
 #include "controller.hpp"
 #include "dpc_status.h"
+#include "focus_status.h"
 #include "geq_status.h"
 #include "lux_status.h"
 #include "metadata.hpp"
@@ -405,6 +406,17 @@ void IPARPi::reportMetadata()
 					 static_cast<int32_t>(blackLevelStatus->black_level_g),
 					 static_cast<int32_t>(blackLevelStatus->black_level_g),
 					 static_cast<int32_t>(blackLevelStatus->black_level_b) });
+
+	FocusStatus *focusStatus = rpiMetadata_.GetLocked<FocusStatus>("focus.status");
+	if (focusStatus && focusStatus->num == 12) {
+		/*
+		 * We get a 4x3 grid of regions by default. Calculate the average
+		 * FoM over the central two positions to give an overall scene FoM.
+		 * This can change later if it is not deemed suitable.
+		 */
+		int32_t focusFoM = (focusStatus->focus_measures[5] + focusStatus->focus_measures[6]) / 2;
+		libcameraMetadata_.set(controls::FocusFoM, focusFoM);
+	}
 }
 
 /*
-- 
2.25.1