boards: nxp: rd_rw612_bga: enable DMIC

Enable DMIC on RW612 BGA board. The DMIC is enabled for both onboard
MEMS microphones for this board, and the board is enabled with the DMIC
sample and test

Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>

boards/nxp/rd_rw612_bga/doc/index.rst

@@ -49,6 +49,8 @@ Supported Features
 +-----------+------------+-----------------------------------+
 | TRNG      | on-chip    | entropy                           |
 +-----------+------------+-----------------------------------+
+| DMIC      | on-chip    | dmic                              |
++-----------+------------+-----------------------------------+
 | WWDT      | on-chip    | watchdog                          |
 +-----------+------------+-----------------------------------+
 | CTIMER    | on-chip    | counter                           |

boards/nxp/rd_rw612_bga/rd_rw612_bga-pinctrl.dtsi

@@ -32,6 +32,16 @@
 		};
 	};
 
+	pinmux_dmic0: pinmux_dmic0 {
+		group0 {
+			pinmux = <IO_MUX_PDM_IO51
+				IO_MUX_PDM_IO52
+				IO_MUX_PDM_IO53
+				IO_MUX_PDM_IO54>;
+			slew-rate = "fast";
+		};
+	};
+
 	pinmux_flexspi: pinmux_flexspi {
 		group0 {
 			pinmux = <IO_MUX_QUAD_SPI_FLASH_IO28

boards/nxp/rd_rw612_bga/rd_rw612_bga.dtsi

@@ -13,6 +13,7 @@
 		sw0 = &sw_4;
 		i2c-0 = &flexcomm2;
 		watchdog0 = &wwdt;
+		dmic-dev = &dmic0;
 	};
 
 	chosen {
@@ -125,6 +126,47 @@ arduino_i2c: &flexcomm2 {
 	};
 };
 
+&dmic0 {
+	pinctrl-0 = <&pinmux_dmic0>;
+	pinctrl-names = "default";
+	use2fs;
+	status = "okay";
+};
+
+/* Configure pdm channels 0-3 with gain, and cutoff settings
+ * appropriate for the attached MEMS microphones.
+ * Note that PDMC0/PDMC1 and PDMC2/PDMC3 are each connected to the same
+ * microphone. For best results, read from PDM HW channel 0 as left channel,
+ * and PDM HW channel 1 as right channel.
+ */
+&pdmc0 {
+	status = "okay";
+	gainshift = <3>;
+	dc-cutoff = "155hz";
+	dc-gain = <1>;
+};
+
+&pdmc1 {
+	status = "okay";
+	gainshift = <3>;
+	dc-cutoff = "155hz";
+	dc-gain = <1>;
+};
+
+&pdmc2 {
+	status = "okay";
+	gainshift = <3>;
+	dc-cutoff = "155hz";
+	dc-gain = <1>;
+};
+
+&pdmc3 {
+	status = "okay";
+	gainshift = <3>;
+	dc-cutoff = "155hz";
+	dc-gain = <1>;
+};
+
 &dma0 {
 	status = "okay";
 };

boards/nxp/rd_rw612_bga/rd_rw612_bga.yaml

@@ -16,6 +16,7 @@ ram: 960
 flash: 65536
 supported:
   - dma
+  - dmic
   - gpio
   - spi
   - i2c

samples/drivers/audio/dmic/boards/rd_rw612_bga.overlay

@@ -0,0 +1,3 @@
+dmic_dev: &dmic0 {
+        status = "okay";
+};

tests/drivers/audio/dmic_api/boards/rd_rw612_bga.overlay

@@ -0,0 +1,39 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Copyright 2023 NXP
+ */
+
+/* Enable PDM channels 0-3,
+ * Gain settings are configured for testing with a PDM generator,
+ * using a -20dbFS sine wave.
+ */
+&dmic0 {
+	dmic-channel@0 {
+		status = "okay";
+		gainshift = <2>;
+		dc-cutoff = "155hz";
+		dc-gain = <1>;
+	};
+
+	dmic-channel@1 {
+		status = "okay";
+		gainshift = <2>;
+		dc-cutoff = "155hz";
+		dc-gain = <1>;
+	};
+
+	dmic-channel@2 {
+		status = "okay";
+		gainshift = <2>;
+		dc-cutoff = "155hz";
+		dc-gain = <1>;
+	};
+
+	dmic-channel@3 {
+		status = "okay";
+		gainshift = <2>;
+		dc-cutoff = "155hz";
+		dc-gain = <1>;
+	};
+};