ipa: rpi: Provide a Camera Helper for the OV64A40

Support the OV64A40 sensor with a camera helper to manage the gain
model, light sensitivity, and control delays.

Signed-off-by: Lee Jackson <lee.jackson@arducam.com>
Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/ipa/rpi/cam_helper/cam_helper_ov64a40.cpp

@@ -0,0 +1,74 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (C) 2021, Raspberry Pi Ltd
+ * Copyright (C) 2023, Ideas on Board Oy.
+ *
+ * cam_helper_ov64a40.cpp - camera information for ov64a40 sensor
+ */
+
+#include <assert.h>
+
+#include "cam_helper.h"
+
+using namespace RPiController;
+
+class CamHelperOv64a40 : public CamHelper
+{
+public:
+	CamHelperOv64a40();
+	uint32_t gainCode(double gain) const override;
+	double gain(uint32_t gainCode) const override;
+	void getDelays(int &exposureDelay, int &gainDelay,
+		       int &vblankDelay, int &hblankDelay) const override;
+	double getModeSensitivity(const CameraMode &mode) const override;
+
+private:
+	/*
+	 * Smallest difference between the frame length and integration time,
+	 * in units of lines.
+	 */
+	static constexpr int frameIntegrationDiff = 32;
+};
+
+CamHelperOv64a40::CamHelperOv64a40()
+	: CamHelper({}, frameIntegrationDiff)
+{
+}
+
+uint32_t CamHelperOv64a40::gainCode(double gain) const
+{
+	return static_cast<uint32_t>(gain * 128.0);
+}
+
+double CamHelperOv64a40::gain(uint32_t gainCode) const
+{
+	return static_cast<double>(gainCode) / 128.0;
+}
+
+void CamHelperOv64a40::getDelays(int &exposureDelay, int &gainDelay,
+				 int &vblankDelay, int &hblankDelay) const
+{
+	/* The driver appears to behave as follows: */
+	exposureDelay = 2;
+	gainDelay = 2;
+	vblankDelay = 2;
+	hblankDelay = 2;
+}
+
+double CamHelperOv64a40::getModeSensitivity(const CameraMode &mode) const
+{
+	if (mode.binX >= 2 && mode.scaleX >= 4) {
+		return 4.0;
+	} else if (mode.binX >= 2 && mode.scaleX >= 2) {
+		return 2.0;
+	} else {
+		return 1.0;
+	}
+}
+
+static CamHelper *create()
+{
+	return new CamHelperOv64a40();
+}
+
+static RegisterCamHelper reg("ov64a40", &create);

src/ipa/rpi/cam_helper/meson.build

@@ -9,6 +9,7 @@ rpi_ipa_cam_helper_sources = files([
     'cam_helper_imx477.cpp',
     'cam_helper_imx519.cpp',
     'cam_helper_imx708.cpp',
+    'cam_helper_ov64a40.cpp',
     'cam_helper_ov9281.cpp',
     'md_parser_smia.cpp',
 ])