From: Jayesh Choudhary <j-choudhary@ti.com>

Add device tree overlay to enable analog audio support on J721S2-EVM
using PCM3168A codec connected to McASP4 serializers.

- Add nodes for sound-card, audio codec, I2C3 and McASP4
- Add pinmux for I2C3, McASP4, AUDIO_EXT_REFCLK1 and WKUP_GPIO_0
- Add GPIO expander (TCA6408) for codec control
- Add GPIO hogs to route I2C3 lines and McASP serializers
- Set idle-state to 0 in mux0 and mux1 for McASP signal routing

Signed-off-by: Jayesh Choudhary <j-choudhary@ti.com>
Co-developed-by: Moteen Shah <m-shah@ti.com>
Signed-off-by: Moteen Shah <m-shah@ti.com>
---
 arch/arm64/boot/dts/ti/Makefile               |   4 +
 .../boot/dts/ti/k3-j721s2-evm-audio.dtso      | 161 ++++++++++++++++++
 2 files changed, 165 insertions(+)
 create mode 100644 arch/arm64/boot/dts/ti/k3-j721s2-evm-audio.dtso

diff --git a/arch/arm64/boot/dts/ti/Makefile b/arch/arm64/boot/dts/ti/Makefile
index ba01a929e06f..17048f2f5043 100644
--- a/arch/arm64/boot/dts/ti/Makefile
+++ b/arch/arm64/boot/dts/ti/Makefile
@@ -138,6 +138,7 @@ dtb-$(CONFIG_ARCH_K3) += k3-j721s2-common-proc-board.dtb
 dtb-$(CONFIG_ARCH_K3) += k3-j721s2-evm-gesi-exp-board.dtbo
 k3-j721s2-evm-dtbs := k3-j721s2-common-proc-board.dtb k3-j721s2-evm-gesi-exp-board.dtbo
 dtb-$(CONFIG_ARCH_K3) += k3-j721s2-evm.dtb
+dtb-$(CONFIG_ARCH_K3) += k3-j721s2-evm-audio.dtbo
 dtb-$(CONFIG_ARCH_K3) += k3-j721s2-evm-pcie1-ep.dtbo
 dtb-$(CONFIG_ARCH_K3) += k3-j721s2-evm-usb0-type-a.dtbo
 
@@ -264,6 +265,8 @@ k3-j721e-evm-pcie1-ep-dtbs := k3-j721e-common-proc-board.dtb \
 	k3-j721e-evm-pcie1-ep.dtbo
 k3-j721e-sk-csi2-dual-imx219-dtbs := k3-j721e-sk.dtb \
 	k3-j721e-sk-csi2-dual-imx219.dtbo
+k3-j721s2-evm-audio-dtbs := k3-j721s2-common-proc-board.dtb \
+	k3-j721s2-evm-audio.dtbo
 k3-j721s2-evm-pcie1-ep-dtbs := k3-j721s2-common-proc-board.dtb \
 	k3-j721s2-evm-pcie1-ep.dtbo
 k3-j721s2-evm-usb0-type-a-dtbs := k3-j721s2-common-proc-board.dtb \
@@ -328,6 +331,7 @@ dtb- += k3-am625-beagleplay-csi2-ov5640.dtb \
 	k3-j721e-evm-pcie0-ep.dtb \
 	k3-j721e-evm-pcie1-ep.dtb \
 	k3-j721e-sk-csi2-dual-imx219.dtb \
+	k3-j721s2-evm-audio.dtb \
 	k3-j721s2-evm-pcie1-ep.dtb \
 	k3-j721s2-evm-usb0-type-a.dtb \
 	k3-j722s-evm-csi2-quad-rpi-cam-imx219.dtb \
diff --git a/arch/arm64/boot/dts/ti/k3-j721s2-evm-audio.dtso b/arch/arm64/boot/dts/ti/k3-j721s2-evm-audio.dtso
new file mode 100644
index 000000000000..2a3ff1cfc650
--- /dev/null
+++ b/arch/arm64/boot/dts/ti/k3-j721s2-evm-audio.dtso
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0-only OR MIT
+/*
+ * Device Tree Overlay for J721S2 Audio Support
+ *
+ * Copyright (C) 2026 Texas Instruments Incorporated - https://www.ti.com/
+ */
+
+/dts-v1/;
+/plugin/;
+
+#include <dt-bindings/gpio/gpio.h>
+
+#include "k3-pinctrl.h"
+
+&{/} {
+	codec_audio: sound {
+		compatible = "ti,j7200-cpb-audio";
+		model = "j721s2-cpb";
+
+		ti,cpb-mcasp = <&mcasp4>;
+		ti,cpb-codec = <&pcm3168a_1>;
+
+		clocks = <&k3_clks 213 0>, <&k3_clks 213 1>,
+			 <&k3_clks 157 299>, <&k3_clks 157 328>;
+		clock-names = "cpb-mcasp-auxclk", "cpb-mcasp-auxclk-48000",
+			      "cpb-codec-scki", "cpb-codec-scki-48000";
+	};
+
+	i2c_mux: mux-controller-2 {
+		compatible = "gpio-mux";
+		#mux-state-cells = <1>;
+		mux-gpios = <&wkup_gpio0 54 GPIO_ACTIVE_HIGH>;
+		idle-state = <1>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&main_i2c3_mux_pins_default>;
+	};
+};
+
+&main_pmx0 {
+	mcasp4_pins_default: mcasp4-default-pins {
+		pinctrl-single,pins = <
+			J721S2_IOPAD(0x0c8, PIN_OUTPUT_PULLDOWN, 1) /* (AD28) MCASP4_ACLKX */
+			J721S2_IOPAD(0x06c, PIN_OUTPUT_PULLDOWN, 1) /* (V26) MCASP4_AFSX */
+			J721S2_IOPAD(0x068, PIN_INPUT_PULLDOWN, 1) /* (U28) MCASP4_AXR1 */
+			J721S2_IOPAD(0x0c4, PIN_OUTPUT_PULLDOWN, 1) /* (AB26) MCASP4_AXR2 */
+			J721S2_IOPAD(0x070, PIN_OUTPUT_PULLDOWN, 1) /* (R27) MCASP4_AXR3 */
+		>;
+	};
+
+	audio_ext_refclk1_pins_default: audio-ext-refclk1-default-pins {
+		pinctrl-single,pins = <
+			J721S2_IOPAD(0x078, PIN_OUTPUT, 1) /* (Y25) MCAN2_RX.AUDIO_EXT_REFCLK1 */
+		>;
+	};
+};
+
+&wkup_pmx2 {
+	main_i2c3_mux_pins_default: main-i2c3-mux-default-pins {
+		pinctrl-single,pins = <
+			J721S2_WKUP_IOPAD(0x038, PIN_OUTPUT, 7) /* (B27) WKUP_GPIO0_54 */
+		>;
+	};
+};
+
+&exp2 {
+	p09-hog {
+		/* P09 - MCASP/TRACE_MUX_S0 */
+		gpio-hog;
+		gpios = <9 GPIO_ACTIVE_HIGH>;
+		output-low;
+		line-name = "MCASP/TRACE_MUX_S0";
+	};
+
+	p10-hog {
+		/* P10 - MCASP/TRACE_MUX_S1 */
+		gpio-hog;
+		gpios = <10 GPIO_ACTIVE_HIGH>;
+		output-high;
+		line-name = "MCASP/TRACE_MUX_S1";
+	};
+};
+
+&mux0 {
+	idle-state = <0>;
+};
+
+&mux1 {
+	idle-state = <0>;
+};
+
+&scm_conf {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	audio_refclk1: clock-controller@42e4 {
+		compatible = "ti,am62-audio-refclk";
+		reg = <0x42e4 0x4>;
+		clocks = <&k3_clks 157 299>;
+		assigned-clocks = <&k3_clks 157 299>;
+		assigned-clock-parents = <&k3_clks 157 328>;
+		#clock-cells = <0>;
+	};
+};
+
+&k3_clks {
+	/* Configure AUDIO_EXT_REFCLK1 pin as output */
+	pinctrl-names = "default";
+	pinctrl-0 = <&audio_ext_refclk1_pins_default>;
+};
+
+&main_i2c3 {
+	status = "okay";
+	pinctrl-names = "default";
+	pinctrl-0 = <&main_i2c3_pins_default>;
+	clock-frequency = <400000>;
+	mux-states = <&i2c_mux 1>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	exp3: gpio@20 {
+		compatible = "ti,tca6408";
+		reg = <0x20>;
+		gpio-controller;
+		#gpio-cells = <2>;
+		gpio-line-names = "CODEC_RSTZ", "CODEC_SPARE1",
+				  "UB926_RESETN", "UB926_LOCK",
+				  "UB926_PWR_SW_CNTRL", "UB926_TUNER_RESET",
+				  "UB926_GPIO_SPARE";
+	};
+
+	pcm3168a_1: audio-codec@44 {
+		compatible = "ti,pcm3168a";
+		reg = <0x44>;
+		#sound-dai-cells = <1>;
+		reset-gpios = <&exp3 0 GPIO_ACTIVE_LOW>;
+		clocks = <&audio_refclk1>;
+		clock-names = "scki";
+		VDD1-supply = <&vsys_3v3>;
+		VDD2-supply = <&vsys_3v3>;
+		VCCAD1-supply = <&vsys_5v0>;
+		VCCAD2-supply = <&vsys_5v0>;
+		VCCDA1-supply = <&vsys_5v0>;
+		VCCDA2-supply = <&vsys_5v0>;
+	};
+};
+
+&mcasp4 {
+	status = "okay";
+	#sound-dai-cells = <0>;
+	pinctrl-names = "default";
+	pinctrl-0 = <&mcasp4_pins_default>;
+	op-mode = <0>;          /* MCASP_IIS_MODE */
+	tdm-slots = <2>;
+	auxclk-fs-ratio = <256>;
+	serial-dir = <	/* 0: INACTIVE, 1: TX, 2: RX */
+		0 2 1 1
+		0 0 0 0
+		0 0 0 0
+		0 0 0 0
+	>;
+};
-- 
2.34.1

On Mon, Mar 30, 2026 at 03:14:59PM +0530, Moteen Shah wrote:
> +	p10-hog {
> +		/* P10 - MCASP/TRACE_MUX_S1 */
> +		gpio-hog;
> +		gpios = <10 GPIO_ACTIVE_HIGH>;
> +		output-high;
> +		line-name = "MCASP/TRACE_MUX_S1";
> +	};
> +};
> +
> +&mux0 {
> +	idle-state = <0>;
> +};
> +
> +&mux1 {
> +	idle-state = <0>;
> +};
> +
> +&scm_conf {
> +	#address-cells = <1>;
> +	#size-cells = <1>;
> +
> +	audio_refclk1: clock-controller@42e4 {
> +		compatible = "ti,am62-audio-refclk";

there is no am62 compatible or DTSI include in the parent SoC file, so
am62n seems to be completely different device than j721s2.

Why does am62b appear here in this context?

Best regards,
Krzysztof