ipa: rkisp1: Add support of Gamma Sensor Linearization control

The GammaSensorLinearization algorithm linearizes the sensor output to
compensate the sensor non-linearities by applying piecewise linear
functions to the red, green and blue channels.

Signed-off-by: Florian Sylvestre <fsylvestre@baylibre.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

4 files changed, 190 insertions, 0 deletions

diff --git a/src/ipa/rkisp1/algorithms/gsl.cpp b/src/ipa/rkisp1/algorithms/gsl.cpp
new file mode 100644
index 00000000..2fd1a23d
--- /dev/null
+++ b/src/ipa/rkisp1/algorithms/gsl.cpp
@@ -0,0 +1,149 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2021-2022, Ideas On Board
+ *
+ * gsl.cpp - RkISP1 Gamma Sensor Linearization control
+ */
+
+#include "gsl.h"
+
+#include <libcamera/base/log.h>
+#include <libcamera/base/utils.h>
+
+#include "libcamera/internal/yaml_parser.h"
+
+#include "linux/rkisp1-config.h"
+
+/**
+ * \file gsl.h
+ */
+
+namespace libcamera {
+
+namespace ipa::rkisp1::algorithms {
+
+/**
+ * \class GammaSensorLinearization
+ * \brief RkISP1 Gamma Sensor Linearization control
+ *
+ * This algorithm linearizes the sensor output to compensate the sensor
+ * non-linearities by applying piecewise linear functions to the red, green and
+ * blue channels.
+ *
+ * The curves are specified in the tuning data and defined using 17 points.
+ *
+ * - The X coordinates are expressed using 16 intervals, with the first point
+ *   at X coordinate 0. Each interval is expressed as a 2-bit value DX (from
+ *   GAMMA_DX_1 to GAMMA_DX_16), stored in the RKISP1_CIF_ISP_GAMMA_DX_LO and
+ *   RKISP1_CIF_ISP_GAMMA_DX_HI registers. The real interval is equal to
+ *   \f$2^{dx+4}\f$. X coordinates are shared between the red, green and blue
+ *   curves.
+ *
+ * - The Y coordinates are specified as 17 values separately for the
+ *   red, green and blue channels, with a 12-bit resolution. Each value must be
+ *   in the [-2048, 2047] range compared to the previous value.
+ */
+
+LOG_DEFINE_CATEGORY(RkISP1Gsl)
+
+static constexpr unsigned int kDegammaXIntervals = 16;
+
+GammaSensorLinearization::GammaSensorLinearization()
+	: initialized_(false)
+{
+}
+
+/**
+ * \copydoc libcamera::ipa::Algorithm::init
+ */
+int GammaSensorLinearization::init([[maybe_unused]] IPAContext &context,
+				   const YamlObject &tuningData)
+{
+	std::vector<uint16_t> xIntervals =
+		tuningData["x-intervals"].getList<uint16_t>().value_or(utils::defopt);
+	if (xIntervals.size() != kDegammaXIntervals) {
+		LOG(RkISP1Gsl, Error)
+			<< "Invalid 'x' coordinates: expected "
+			<< kDegammaXIntervals << " elements, got "
+			<< xIntervals.size();
+
+		return -EINVAL;
+	}
+
+	/* Compute gammaDx_ intervals from xIntervals values */
+	gammaDx_[0] = 0;
+	gammaDx_[1] = 0;
+	for (unsigned int i = 0; i < kDegammaXIntervals; ++i)
+		gammaDx_[i / 8] |= (xIntervals[i] & 0x07) << ((i % 8) * 4);
+
+	const YamlObject &yObject = tuningData["y"];
+	if (!yObject.isDictionary()) {
+		LOG(RkISP1Gsl, Error)
+			<< "Issue while parsing 'y' in tuning file: "
+			<< "entry must be a dictionary";
+		return -EINVAL;
+	}
+
+	curveYr_ = yObject["red"].getList<uint16_t>().value_or(utils::defopt);
+	if (curveYr_.size() != RKISP1_CIF_ISP_DEGAMMA_CURVE_SIZE) {
+		LOG(RkISP1Gsl, Error)
+			<< "Invalid 'y:red' coordinates: expected "
+			<< RKISP1_CIF_ISP_DEGAMMA_CURVE_SIZE
+			<< " elements, got " << curveYr_.size();
+		return -EINVAL;
+	}
+
+	curveYg_ = yObject["green"].getList<uint16_t>().value_or(utils::defopt);
+	if (curveYg_.size() != RKISP1_CIF_ISP_DEGAMMA_CURVE_SIZE) {
+		LOG(RkISP1Gsl, Error)
+			<< "Invalid 'y:green' coordinates: expected "
+			<< RKISP1_CIF_ISP_DEGAMMA_CURVE_SIZE
+			<< " elements, got " << curveYg_.size();
+		return -EINVAL;
+	}
+
+	curveYb_ = yObject["blue"].getList<uint16_t>().value_or(utils::defopt);
+	if (curveYb_.size() != RKISP1_CIF_ISP_DEGAMMA_CURVE_SIZE) {
+		LOG(RkISP1Gsl, Error)
+			<< "Invalid 'y:blue' coordinates: expected "
+			<< RKISP1_CIF_ISP_DEGAMMA_CURVE_SIZE
+			<< " elements, got " << curveYb_.size();
+		return -EINVAL;
+	}
+
+	initialized_ = true;
+	return 0;
+}
+
+/**
+ * \copydoc libcamera::ipa::Algorithm::prepare
+ */
+void GammaSensorLinearization::prepare(IPAContext &context,
+				       rkisp1_params_cfg *params)
+{
+	if (context.frameContext.frameCount > 0)
+		return;
+
+	if (!initialized_)
+		return;
+
+	params->others.sdg_config.xa_pnts.gamma_dx0 = gammaDx_[0];
+	params->others.sdg_config.xa_pnts.gamma_dx1 = gammaDx_[1];
+
+	std::copy(curveYr_.begin(), curveYr_.end(),
+		  params->others.sdg_config.curve_r.gamma_y);
+	std::copy(curveYg_.begin(), curveYg_.end(),
+		  params->others.sdg_config.curve_g.gamma_y);
+	std::copy(curveYb_.begin(), curveYb_.end(),
+		  params->others.sdg_config.curve_b.gamma_y);
+
+	params->module_en_update |= RKISP1_CIF_ISP_MODULE_SDG;
+	params->module_ens |= RKISP1_CIF_ISP_MODULE_SDG;
+	params->module_cfg_update |= RKISP1_CIF_ISP_MODULE_SDG;
+}
+
+REGISTER_IPA_ALGORITHM(GammaSensorLinearization, "GammaSensorLinearization")
+
+} /* namespace ipa::rkisp1::algorithms */
+
+} /* namespace libcamera */
diff --git a/src/ipa/rkisp1/algorithms/gsl.h b/src/ipa/rkisp1/algorithms/gsl.h
new file mode 100644
index 00000000..db287dc2
--- /dev/null
+++ b/src/ipa/rkisp1/algorithms/gsl.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2021-2022, Ideas On Board
+ *
+ * gsl.h - RkISP1 Gamma Sensor Linearization control
+ */
+
+#pragma once
+
+#include "algorithm.h"
+
+namespace libcamera {
+
+namespace ipa::rkisp1::algorithms {
+
+class GammaSensorLinearization : public Algorithm
+{
+public:
+	GammaSensorLinearization();
+	~GammaSensorLinearization() = default;
+
+	int init(IPAContext &context, const YamlObject &tuningData) override;
+	void prepare(IPAContext &context, rkisp1_params_cfg *params) override;
+
+private:
+	bool initialized_;
+	uint32_t gammaDx_[2];
+	std::vector<uint16_t> curveYr_;
+	std::vector<uint16_t> curveYg_;
+	std::vector<uint16_t> curveYb_;
+};
+
+} /* namespace ipa::rkisp1::algorithms */
+} /* namespace libcamera */
diff --git a/src/ipa/rkisp1/algorithms/meson.build b/src/ipa/rkisp1/algorithms/meson.build
index 7ec53d89..0597c353 100644
--- a/src/ipa/rkisp1/algorithms/meson.build
+++ b/src/ipa/rkisp1/algorithms/meson.build
@@ -4,4 +4,5 @@ rkisp1_ipa_algorithms = files([
     'agc.cpp',
     'awb.cpp',
     'blc.cpp',
+    'gsl.cpp',
 ])
diff --git a/src/ipa/rkisp1/data/ov5640.yaml b/src/ipa/rkisp1/data/ov5640.yaml
index 232d8ae8..13f76412 100644
--- a/src/ipa/rkisp1/data/ov5640.yaml
+++ b/src/ipa/rkisp1/data/ov5640.yaml
@@ -10,4 +10,10 @@ algorithms:
       Gr: 256
       Gb: 256
       B:  256
+  - GammaSensorLinearization:
+      x-intervals: [ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 ]
+      y:
+        red:   [ 0, 256, 512, 768, 1024, 1280, 1536, 1792, 2048, 2304, 2560, 2816, 3072, 3328, 3584, 3840, 4095 ]
+        green: [ 0, 256, 512, 768, 1024, 1280, 1536, 1792, 2048, 2304, 2560, 2816, 3072, 3328, 3584, 3840, 4095 ]
+        blue:  [ 0, 256, 512, 768, 1024, 1280, 1536, 1792, 2048, 2304, 2560, 2816, 3072, 3328, 3584, 3840, 4095 ]
 ...