tests: drivers: audio: Add tests for PDM

Added tests for PDM that check PDM_CLK output frequency
and ensure that dmic API works as expected.

Signed-off-by: Michał Stasiak <[email protected]>

CODEOWNERS

@@ -786,6 +786,7 @@
 /tests/bluetooth/bsim/nrf_auraconfig/     @nrfconnect/ncs-audio
 /tests/bluetooth/tester/                  @carlescufi @nrfconnect/ncs-paladin
 /tests/crypto/                            @stephen-nordic @magnev
+/tests/drivers/audio/pdm_loopback/        @nrfconnect/ncs-low-level-test
 /tests/drivers/gpio/                      @nrfconnect/ncs-low-level-test @nrfconnect/ncs-ll-ursus
 /tests/drivers/flash/flash_rpc/           @nrfconnect/ncs-pluto
 /tests/drivers/flash_patch/               @nrfconnect/ncs-pluto

tests/drivers/audio/pdm_loopback/CMakeLists.txt

@@ -0,0 +1,12 @@
+#
+# Copyright (c) 2024 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(pdm_loopback)
+
+target_sources(app PRIVATE src/main.c)

tests/drivers/audio/pdm_loopback/Kconfig

@@ -0,0 +1,36 @@
+#
+# Copyright (c) 2024 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+source "Kconfig.zephyr"
+
+config TEST_PDM_SAMPLING_RATE
+	int "PDM sample rate in Hz"
+	default 10000
+	help
+	  The test will use it to define frequency of PDM sampling and
+	  calculate the size of the buffer.
+
+config TEST_PDM_EXPECTED_FREQUENCY
+	int "Expected PDM_CLK frequency in Hz"
+	default 1000000
+	help
+	  The test will use it to confirm that the captured PDM_CLK
+	  frequency in correct.
+
+config TEST_PDM_SAMPLING_TIME
+	int "PDM sampling time for one block in ms"
+	default 100
+	help
+	  The test will use it to calculate the size of data block and
+	  determine the period of capturing timer.
+
+config TEST_USE_DMM
+	bool "Use of DMM prealocation"
+	default n
+	help
+	  The test will use it to determine whether to prealocate DMM
+	  buffer or use regular mem slab and allocate dmm buffer inside
+	  PDM driver.

tests/drivers/audio/pdm_loopback/boards/nrf54h20dk_nrf54h20_cpuapp.overlay

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2024 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+
+/ {
+	gpio_test {
+		compatible = "gpio-leds";
+		pulse_counter: pulse_counter {
+			gpios = <&gpio1 3 GPIO_ACTIVE_HIGH>;
+		};
+	};
+};
+
+&pinctrl {
+	pdm0_default_alt: pdm0_default_alt {
+		group1 {
+			psels = <NRF_PSEL(PDM_CLK, 1, 2)>,
+				<NRF_PSEL(PDM_DIN, 1, 4)>;
+		};
+	};
+};
+
+pdm_dev: &pdm0 {
+	status = "okay";
+	pinctrl-0 = <&pdm0_default_alt>;
+	pinctrl-names = "default";
+	clock-source = "PCLK32M";
+	memory-regions = <&cpuapp_dma_region>;
+};
+
+&gpio1 {
+	status = "okay";
+};
+
+&gpiote130 {
+	owned-channels = <0>;
+	status = "okay";
+};
+
+&timer130 {
+	status = "okay";
+};
+
+&dppic130 {
+	owned-channels = <0>;
+	source-channels = <0>;
+	status = "okay";
+};
+
+&dppic133 {
+	owned-channels = <0>;
+	sink-channels = <0>;
+	status = "okay";
+};

tests/drivers/audio/pdm_loopback/boards/nrf54l15dk_nrf54l15_cpuapp.overlay

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2024 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+
+/ {
+	gpio_test {
+		compatible = "gpio-leds";
+		pulse_counter: pulse_counter {
+			gpios = <&gpio1 11 GPIO_ACTIVE_HIGH>;
+		};
+	};
+};
+
+&pinctrl {
+	pdm20_default_alt: pdm20_default_alt {
+		group1 {
+			psels = <NRF_PSEL(PDM_CLK, 1, 10)>,
+				<NRF_PSEL(PDM_DIN, 1, 12)>;
+		};
+	};
+};
+
+pdm_dev: &pdm20 {
+	status = "okay";
+	pinctrl-0 = <&pdm20_default_alt>;
+	pinctrl-names = "default";
+	clock-source = "PCLK32M";
+};
+
+&gpio1 {
+	status = "okay";
+};
+
+&timer00 {
+	status = "okay";
+};

tests/drivers/audio/pdm_loopback/prj.conf

@@ -0,0 +1,13 @@
+#
+# Copyright (c) 2024 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+CONFIG_ZTEST=y
+CONFIG_TEST_USERSPACE=y
+
+CONFIG_AUDIO=y
+CONFIG_AUDIO_DMIC=y
+CONFIG_GPIO=y
+CONFIG_NRFX_GPPI=y