[PATCH v4 0/2] Enable audio support for J721S2 EVM

[PATCH v4 0/2] Enable audio support for J721S2 EVM

[Moteen Shah]

This patch series, adds support for analog audio on J721S2 EVM using
device tree overlays.

Earlier version of the patchset sent upstream[0] was rejected as
its dependency[1], which resolves the DTBS check errors introduced
by [0] also got rejected on the grounds of ABI breakage.

Another solution to fix the DTBS check errors introduced by [0] is
to modify the ti,j721e-system-controller.yaml binding to allow
audio-refclk as clock-controller child. This is done in the first
patch of this series.

Changes sinve v3:
Link to v3: https://lore.kernel.org/all/20260330094459.128648-1-m-shah@ti.com/
- Changed compatible from simple items to oneOf to support both AM62 (legacy)
  and J721S2 (primary SoC-specific) compatible strings.
- Pick up missing R/B given in V2 of the patch series by Hari and Rob.

Link to v2: https://lore.kernel.org/all/20260205130707.2033197-1-m-shah@ti.com/
Link to v1: https://lore.kernel.org/all/20260112104536.83309-1-m-shah@ti.com/

Bootlogs: https://gist.github.com/Jamm02/f586087dad227450abe8637e8a688c68

Jayesh Choudhary (1):
  arm64: dts: ti: Add audio overlay for k3-j721s2-evm

Moteen Shah (1):
  dt-bindings: ti: Update audio-refclk binding and j721e system
    controller

 .../bindings/clock/ti,am62-audio-refclk.yaml  |   8 +-
 .../soc/ti/ti,j721e-system-controller.yaml    |   6 +-
 arch/arm64/boot/dts/ti/Makefile               |   4 +
 .../boot/dts/ti/k3-j721s2-evm-audio.dtso      | 161 ++++++++++++++++++
 4 files changed, 175 insertions(+), 4 deletions(-)
 create mode 100644 arch/arm64/boot/dts/ti/k3-j721s2-evm-audio.dtso

-- 
2.34.1

[PATCH v4 1/2] dt-bindings: ti: Update audio-refclk binding and j721e system controller

[Moteen Shah]

Add ti,j721s2-audio-refclk as a supported compatible string in the
ti,am62-audio-refclk binding. J721S2 uses the same audio reference
clock IP block first introduced on AM62. Per writing-bindings
guidelines, the J721S2-specific compatible is added as the primary
string with ti,am62-audio-refclk as the fallback.

Also extend the ti,j721e-system-controller clock-controller@ child
pattern to accept audio-refclk schemas alongside ehrpwm-tbclk via a
oneOf constraint, fixing the alphanumerical ordering of $refs.

Signed-off-by: Moteen Shah <m-shah@ti.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
---
 .../devicetree/bindings/clock/ti,am62-audio-refclk.yaml   | 8 ++++++--
 .../bindings/soc/ti/ti,j721e-system-controller.yaml       | 6 ++++--
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/Documentation/devicetree/bindings/clock/ti,am62-audio-refclk.yaml b/Documentation/devicetree/bindings/clock/ti,am62-audio-refclk.yaml
index b2e40bd39a3a..6c8fb0793070 100644
--- a/Documentation/devicetree/bindings/clock/ti,am62-audio-refclk.yaml
+++ b/Documentation/devicetree/bindings/clock/ti,am62-audio-refclk.yaml
@@ -11,8 +11,12 @@ maintainers:
 
 properties:
   compatible:
-    items:
-      - const: ti,am62-audio-refclk
+    oneOf:
+      - items:
+          - const: ti,am62-audio-refclk
+      - items:
+          - const: ti,j721s2-audio-refclk
+          - const: ti,am62-audio-refclk
 
   reg:
     maxItems: 1
diff --git a/Documentation/devicetree/bindings/soc/ti/ti,j721e-system-controller.yaml b/Documentation/devicetree/bindings/soc/ti/ti,j721e-system-controller.yaml
index f3bd0be3b279..364be49f8c7c 100644
--- a/Documentation/devicetree/bindings/soc/ti/ti,j721e-system-controller.yaml
+++ b/Documentation/devicetree/bindings/soc/ti/ti,j721e-system-controller.yaml
@@ -53,9 +53,11 @@ patternProperties:
 
   "^clock-controller@[0-9a-f]+$":
     type: object
-    $ref: /schemas/clock/ti,am654-ehrpwm-tbclk.yaml#
+    oneOf:
+      - $ref: /schemas/clock/ti,am62-audio-refclk.yaml#
+      - $ref: /schemas/clock/ti,am654-ehrpwm-tbclk.yaml#
     description:
-      Clock provider for TI EHRPWM nodes.
+      Clock provider for TI EHRPWM or Audio Reference Clock nodes.
 
   "phy@[0-9a-f]+$":
     type: object
-- 
2.34.1

[PATCH v4 2/2] arm64: dts: ti: Add audio overlay for k3-j721s2-evm

[Moteen Shah]

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

Reviewed-by: Hari Prasath Gujulan Elango <gehariprasath@ti.com>
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..6ed4d6fc414d
--- /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,j721s2-audio-refclk", "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

Re: [PATCH v4 2/2] arm64: dts: ti: Add audio overlay for k3-j721s2-evm

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The audio device tree overlay fails to disable conflicting CAN node devices from the base board, causing McASP audio signal routing to be silently broken when CAN interfaces are brought up.
--

commit c1ba2c3319437f9663a75e0a335a9f4615ec2ea6
Author: Jayesh Choudhary <j-choudhary@ti.com>

arm64: dts: ti: Add audio overlay for k3-j721s2-evm

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

> 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 0000000000000..6ed4d6fc414d9
> --- /dev/null
> +++ b/arch/arm64/boot/dts/ti/k3-j721s2-evm-audio.dtso
[ ... ]
> +&mux0 {
> +	idle-state = <0>;
> +};
> +
> +&mux1 {
> +	idle-state = <0>;
> +};

Will this signal routing be silently broken if the CAN interfaces are brought
up?

The base board device tree (k3-j721s2-common-proc-board.dts) enables
main_mcan3 and main_mcan5, which use PHYs configured with mux-states = <&mux0 1>
and <&mux1 1>. The McASP node here does not claim the mux via the mux-control
API, relying entirely on the idle-state fallback.

When the CAN interfaces are brought up (e.g., ifconfig can3 up), the CAN PHY
driver will call mux_state_select(), actively driving the mux controllers to
state 1. This overrides the idle-state 0 required for audio, physically breaking
the McASP signal routing without the audio driver's knowledge.

Should the overlay explicitly disable main_mcan3 and main_mcan5 to prevent this
hardware conflict?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260519142341.2531948-1-m-shah@ti.com?part=2