samples: zephyr: drivers: audio: dmic: Run on nRF54LM20A PDK

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

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

Author: nordic-segl

samples/zephyr/drivers/audio/dmic/boards/nrf54lm20apdk_nrf54lm20a_cpuapp.overlay

@@ -4,11 +4,15 @@
  * 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'.
+ */
+
 &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)>;
 		};
 	};
 };

samples/zephyr/drivers/audio/dmic/boards/nrf54lm20apdk_nrf54lm20a_cpuapp_0_0_0.overlay

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+
+/* Test requires loopback between P1.10 and P1.11 */
+
+&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";
+};

samples/zephyr/drivers/audio/dmic/sample.yaml

@@ -15,5 +15,7 @@ tests:
         - "Exiting"
     platform_allow:
       - nrf54lm20apdk/nrf54lm20a/cpuapp
+      - [email protected]/nrf54lm20a/cpuapp
     integration_platforms:
       - nrf54lm20apdk/nrf54lm20a/cpuapp
+      - [email protected]/nrf54lm20a/cpuapp