ipa: rpi: pisp: Add decompand support using PiSP hardware block

src/ipa/rpi/controller/decompand_algorithm.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include "algorithm.h"
+
+namespace RPiController {
+
+class DecompandAlgorithm : public Algorithm
+{
+public:
+	DecompandAlgorithm(Controller *controller) : Algorithm(controller) {}
+  virtual void initialValues(uint16_t lut[])
+  {
+    static const uint16_t defaultLut[] = {
+      3072, 3072, 3072, 3072, 3136, 3200, 3264, 3328,
+      3392, 3456, 3520, 3584, 3648, 3712, 3776, 3840,
+      3904, 3968, 4032, 4096, 4608, 5120, 5632, 6144,
+      6656, 7168, 7680, 8192, 8704, 9216, 9728, 10240,
+      10752, 11264, 11776, 12288, 12800, 13312, 13824, 14336,
+      14848, 15360, 17408, 19456, 21504, 23552, 25600, 27648,
+      29696, 31744, 33792, 35840, 37888, 39936, 41984, 44032,
+      46080, 48128, 50176, 52224, 54272, 56320, 58368, 60416,
+      62464
+    };
+
+    for (size_t i = 0; i < sizeof(defaultLut) / sizeof(defaultLut[0]); ++i)
+      lut[i] = defaultLut[i];
+  }
+};
+} /* namespace RPiController */

src/ipa/rpi/controller/decompand_status.h

@@ -0,0 +1,7 @@
+#pragma once
+
+#include <stdint.h>
+
+struct DecompandStatus {
+	uint16_t lut[65];
+};

src/ipa/rpi/controller/meson.build

@@ -14,6 +14,7 @@ rpi_ipa_controller_sources = files([
     'rpi/cac.cpp',
     'rpi/ccm.cpp',
     'rpi/contrast.cpp',
+    'rpi/decompand.cpp',
     'rpi/denoise.cpp',
     'rpi/dpc.cpp',
     'rpi/geq.cpp',

src/ipa/rpi/controller/rpi/decompand.cpp

@@ -0,0 +1,68 @@
+#include <libcamera/base/log.h>
+
+#include "../decompand_status.h"
+
+#include "decompand.h"
+
+using namespace RPiController;
+using namespace libcamera;
+
+LOG_DEFINE_CATEGORY(RPiDecompand)
+
+#define NAME "rpi.decompand"
+
+Decompand::Decompand(Controller *controller)
+	: DecompandAlgorithm(controller)
+{
+}
+
+char const *Decompand::name() const
+{
+	return NAME;
+}
+
+int Decompand::read(const libcamera::YamlObject &params)
+{
+	if (!params.contains("lut") || !params["lut"].isList() || params["lut"].size() != 65) {
+		LOG(RPiDecompand, Error) << "Expected LUT with 65 elements";
+		return -EINVAL;
+	}
+
+	for (unsigned int i = 0; i < 65; ++i) {
+		std::optional<uint16_t> value = params["lut"][i].get<uint16_t>();
+		if (!value.has_value()) {
+			LOG(RPiDecompand, Error) << "Invalid LUT value at index " << i;
+			return -EINVAL;
+		}
+		decompandLUT_[i] = value.value();
+	}
+
+	return 0;
+}
+
+void Decompand::initialValues(uint16_t LUT[])
+{
+  for (size_t i = 0; i < sizeof(decompandLUT_) / sizeof(decompandLUT_[0]); ++i)
+	{
+    LUT[i] = decompandLUT_[i];
+	}
+}
+
+void Decompand::prepare(Metadata *imageMetadata)
+{
+	struct DecompandStatus status;
+	for (size_t i = 0; i < sizeof(decompandLUT_) / sizeof(decompandLUT_[0]); ++i)
+	{
+    status.lut[i] = decompandLUT_[i];
+	}
+
+	imageMetadata->set("decompand.status", status);
+}
+
+/* Register algorithm with the system. */
+static Algorithm *create(Controller *controller)
+{
+	return new Decompand(controller);
+}
+
+static RegisterAlgorithm reg(NAME, &create);

src/ipa/rpi/controller/rpi/decompand.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include "../decompand_algorithm.h"
+#include "../decompand_status.h"
+
+namespace RPiController {
+
+class Decompand : public DecompandAlgorithm
+{
+public:
+	Decompand(Controller *controller);
+	char const *name() const override;
+	int read(const libcamera::YamlObject &params) override;
+	void initialValues(uint16_t LUT[]) override;
+	void prepare(Metadata *imageMetadata) override;
+
+private:
+	uint16_t decompandLUT_[65];
+};
+
+} /* namespace RPiController */