tests: zephyr: drivers: audio: dmic_api: Run on nRF54LM20A PDK

Add overlay that defines correct loopback to run the test
on nRF54LM20A PDK.

Signed-off-by: Sebastian Głąb <[email protected]>

Author: nordic-segl

tests/zephyr/drivers/audio/dmic_api/boards/nrf54lm20apdk_nrf54lm20a_cpuapp.overlay

@@ -4,6 +4,10 @@
  * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
  */
 
+/* Test requires loopback between P1.18 and P1.24.
+ * For best performance, PDM_CLK shall be on 'Clock pin'.
+ */
+
 / {
 	aliases {
 		dmic-dev = &pdm20;
@@ -13,8 +17,8 @@
 &pinctrl {
 	pdm20_default_alt: pdm20_default_alt {
 		group1 {
-			psels = <NRF_PSEL(PDM_CLK, 1, 10)>,
-				<NRF_PSEL(PDM_DIN, 1, 11)>;
+			psels = <NRF_PSEL(PDM_CLK, 1, 18)>,
+				<NRF_PSEL(PDM_DIN, 1, 24)>;
 		};
 	};
 };

tests/zephyr/drivers/audio/dmic_api/boards/nrf54lm20apdk_nrf54lm20a_cpuapp_0_0_0.overlay

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+
+/* Test requires loopback between P1.10 and P1.11 */
+
+/ {
+	aliases {
+		dmic-dev = &pdm20;
+	};
+};
+
+&pinctrl {
+	pdm20_default_alt: pdm20_default_alt {
+		group1 {
+			psels = <NRF_PSEL(PDM_CLK, 1, 10)>,
+				<NRF_PSEL(PDM_DIN, 1, 11)>;
+		};
+	};
+};
+
+dmic_dev: &pdm20 {
+	status = "okay";
+	pinctrl-0 = <&pdm20_default_alt>;
+	pinctrl-names = "default";
+	clock-source = "PCLK32M";
+};

tests/zephyr/drivers/audio/dmic_api/testcase.yaml

@@ -6,5 +6,7 @@ tests:
     harness: ztest
     platform_allow:
       - nrf54lm20apdk/nrf54lm20a/cpuapp
+      - [email protected]/nrf54lm20a/cpuapp
     integration_platforms:
       - nrf54lm20apdk/nrf54lm20a/cpuapp
+      - [email protected]/nrf54lm20a/cpuapp