tests: drivers: disk: add test for the FFAT disk

Add FAT16 and FAT32 tests for the FFAT disk using ELM FAT file system
support.

Signed-off-by: Johann Fischer <johann.fischer@nordicsemi.no>

Author: jfischer-no

tests/drivers/disk/ffat/CMakeLists.txt

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+# Copyright (c) 2023 Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(test_ffat)
+
+target_sources(app PRIVATE
+    src/main.c
+)

tests/drivers/disk/ffat/app.overlay

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+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	ffatdisk0 {
+		compatible = "zephyr,ffat-disk";
+		disk-name = "RAM";
+		sector-size = <512>;
+		sector-count = <32680>;
+		sector-per-cluster = <1>;
+	};
+
+	ffatdisk1 {
+		compatible = "zephyr,ffat-disk";
+		disk-name = "NAND";
+		sector-size = <512>;
+		sector-count = <262144>;
+		sector-per-cluster = <4>;
+	};
+
+	ffatdisk2 {
+		compatible = "zephyr,ffat-disk";
+		disk-name = "CF";
+		sector-size = <1024>;
+		sector-count = <524288>;
+		sector-per-cluster = <8>;
+	};
+
+	ffatdisk3 {
+		compatible = "zephyr,ffat-disk";
+		disk-name = "SD";
+		sector-size = <4096>;
+		sector-count = <1048576>;
+		sector-per-cluster = <32>;
+	};
+
+	ffatdisk4 {
+		compatible = "zephyr,ffat32-disk", "zephyr,ffat-disk";
+		disk-name = "SD2";
+		sector-size = <512>;
+		sector-count = <131072>;
+		sector-per-cluster = <1>;
+	};
+
+	ffatdisk5 {
+		compatible = "zephyr,ffat32-disk", "zephyr,ffat-disk";
+		disk-name = "USB";
+		sector-size = <512>;
+		sector-count = <524288>;
+		sector-per-cluster = <4>;
+	};
+
+	ffatdisk6 {
+		compatible = "zephyr,ffat32-disk", "zephyr,ffat-disk";
+		disk-name = "USB2";
+		sector-size = <1024>;
+		sector-count = <1048576>;
+		sector-per-cluster = <8>;
+	};
+
+	ffatdisk7 {
+		compatible = "zephyr,ffat32-disk", "zephyr,ffat-disk";
+		disk-name = "USB3";
+		sector-size = <4096>;
+		sector-count = <16777216>;
+		sector-per-cluster = <64>;
+	};
+};

tests/drivers/disk/ffat/prj.conf

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+# Copyright (c) 2023 Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+
+CONFIG_LOG=y
+CONFIG_ZTEST=y
+
+CONFIG_DISK_ACCESS=y
+CONFIG_FILE_SYSTEM=y
+CONFIG_FAT_FILESYSTEM_ELM=y
+CONFIG_FS_FATFS_MOUNT_MKFS=n
+CONFIG_FS_FATFS_MIN_SS=512
+CONFIG_FS_FATFS_MAX_SS=4096