ipa: rpi: pisp: Add a DecompandAlgorithm class

The decompand algorithm implementation will subclass the
DecompandAlgorithm class. This will be needed for setting the initial
decompand values in a future commit.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>

Author: naushir

src/ipa/rpi/controller/decompand_algorithm.h

@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (C) 2025, Raspberry Pi Ltd
+ *
+ * Decompand control algorithm interface
+ */
+#pragma once
+
+#include "libipa/pwl.h"
+
+#include "algorithm.h"
+
+namespace RPiController {
+
+class DecompandAlgorithm : public Algorithm
+{
+public:
+	DecompandAlgorithm(Controller *controller = NULL)
+		: Algorithm(controller)
+	{
+	}
+};
+
+} /* namespace RPiController */

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

@@ -13,7 +13,7 @@ LOG_DEFINE_CATEGORY(RPiDecompand)
 #define NAME "rpi.decompand"
 
 Decompand::Decompand(Controller *controller)
-	: Algorithm(controller)
+	: DecompandAlgorithm(controller)
 {
 }
 

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

@@ -2,18 +2,17 @@
 
 #include <libipa/pwl.h>
 
+#include "../decompand_algorithm.h"
 #include "../decompand_status.h"
 
-#include "algorithm.h"
-
 namespace RPiController {
 
 struct DecompandConfig {
 	uint32_t bitdepth;
 	libcamera::ipa::Pwl decompandCurve;
 };
 
-class Decompand : public Algorithm
+class Decompand : public DecompandAlgorithm
 {
 public:
 	Decompand(Controller *controller = NULL);