[PATCH 0/3] Enable audio support for J721S2-EVM

[PATCH 0/3] Enable audio support for J721S2-EVM

[Jayesh Choudhary]

These 3 patches add the support to enable audio on J721S2-EVM.

This required the i2c-mux support[0] which is now in linux tree.

Now, this series ***depends upon only one dts change[1]*** to ensure there
are no dtbs_check warnings (no functional issues):
"ti,j721e-system-controller.yaml" refers to "ti,am654-ehrpwm-tbclk.yaml"
for clock-controller nodes, but for audio we need "ti,am62-audio-refclk".
When scm_conf is "simple-bus", there are no such warnings.

Test log: https://gist.github.com/Jayesh2000/840c19ef8f9b7f0f75dedd015ccbf98a

[0]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0fc829dbde9bf1f349631c677a85e08782037ecf
[1]: https://lore.kernel.org/all/20250603095609.33569-4-j-choudhary@ti.com/


Jayesh Choudhary (3):
  arm64: dts: ti: k3-j721s2-main: Add McASP nodes
  arm64: dts: ti: k3-j721s2-main: Add audio_refclk node
  arm64: dts: ti: k3-j721s2-common-proc-board: Enable analog audio
    support

 .../dts/ti/k3-j721s2-common-proc-board.dts    | 131 ++++++++++++++++++
 arch/arm64/boot/dts/ti/k3-j721s2-main.dtsi    |  99 +++++++++++++
 2 files changed, 230 insertions(+)

-- 
2.34.1

[PATCH 1/3] arm64: dts: ti: k3-j721s2-main: Add McASP nodes

[Jayesh Choudhary]

Add McASP 0-4 instances and keep them disabled because several
required properties are missing as they are board specific.

Signed-off-by: Jayesh Choudhary <j-choudhary@ti.com>
---
 arch/arm64/boot/dts/ti/k3-j721s2-main.dtsi | 90 ++++++++++++++++++++++
 1 file changed, 90 insertions(+)

diff --git a/arch/arm64/boot/dts/ti/k3-j721s2-main.dtsi b/arch/arm64/boot/dts/ti/k3-j721s2-main.dtsi
index 605f753d3258..6dee0c573980 100644
--- a/arch/arm64/boot/dts/ti/k3-j721s2-main.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-j721s2-main.dtsi
@@ -2066,4 +2066,94 @@ gpu: gpu@4e20000000 {
 		power-domain-names = "a", "b";
 		dma-coherent;
 	};
+
+	mcasp0: mcasp@2b00000 {
+		compatible = "ti,am33xx-mcasp-audio";
+		reg = <0x00 0x02b00000 0x00 0x2000>,
+		      <0x00 0x02b08000 0x00 0x1000>;
+		reg-names = "mpu","dat";
+		interrupts = <GIC_SPI 544 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 545 IRQ_TYPE_LEVEL_HIGH>;
+		interrupt-names = "tx", "rx";
+		dmas = <&main_udmap 0xc400>, <&main_udmap 0x4400>;
+		dma-names = "tx", "rx";
+		clocks = <&k3_clks 209 0>;
+		clock-names = "fck";
+		assigned-clocks = <&k3_clks 209 0>;
+		assigned-clock-parents = <&k3_clks 209 1>;
+		power-domains = <&k3_pds 209 TI_SCI_PD_EXCLUSIVE>;
+		status = "disabled";
+	};
+
+	mcasp1: mcasp@2b10000 {
+		compatible = "ti,am33xx-mcasp-audio";
+		reg = <0x00 0x02b10000 0x00 0x2000>,
+		      <0x00 0x02b18000 0x00 0x1000>;
+		reg-names = "mpu","dat";
+		interrupts = <GIC_SPI 546 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 547 IRQ_TYPE_LEVEL_HIGH>;
+		interrupt-names = "tx", "rx";
+		dmas = <&main_udmap 0xc401>, <&main_udmap 0x4401>;
+		dma-names = "tx", "rx";
+		clocks = <&k3_clks 210 0>;
+		clock-names = "fck";
+		assigned-clocks = <&k3_clks 210 0>;
+		assigned-clock-parents = <&k3_clks 210 1>;
+		power-domains = <&k3_pds 210 TI_SCI_PD_EXCLUSIVE>;
+		status = "disabled";
+	};
+
+	mcasp2: mcasp@2b20000 {
+		compatible = "ti,am33xx-mcasp-audio";
+		reg = <0x00 0x02b20000 0x00 0x2000>,
+		      <0x00 0x02b28000 0x00 0x1000>;
+		reg-names = "mpu","dat";
+		interrupts = <GIC_SPI 548 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 549 IRQ_TYPE_LEVEL_HIGH>;
+		interrupt-names = "tx", "rx";
+		dmas = <&main_udmap 0xc402>, <&main_udmap 0x4402>;
+		dma-names = "tx", "rx";
+		clocks = <&k3_clks 211 0>;
+		clock-names = "fck";
+		assigned-clocks = <&k3_clks 211 0>;
+		assigned-clock-parents = <&k3_clks 211 1>;
+		power-domains = <&k3_pds 211 TI_SCI_PD_EXCLUSIVE>;
+		status = "disabled";
+	};
+
+	mcasp3: mcasp@2b30000 {
+		compatible = "ti,am33xx-mcasp-audio";
+		reg = <0x00 0x02b30000 0x00 0x2000>,
+		      <0x00 0x02b38000 0x00 0x1000>;
+		reg-names = "mpu","dat";
+		interrupts = <GIC_SPI 550 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 551 IRQ_TYPE_LEVEL_HIGH>;
+		interrupt-names = "tx", "rx";
+		dmas = <&main_udmap 0xc403>, <&main_udmap 0x4403>;
+		dma-names = "tx", "rx";
+		clocks = <&k3_clks 212 0>;
+		clock-names = "fck";
+		assigned-clocks = <&k3_clks 212 0>;
+		assigned-clock-parents = <&k3_clks 212 1>;
+		power-domains = <&k3_pds 212 TI_SCI_PD_EXCLUSIVE>;
+		status = "disabled";
+	};
+
+	mcasp4: mcasp@2b40000 {
+		compatible = "ti,am33xx-mcasp-audio";
+		reg = <0x00 0x02b40000 0x00 0x2000>,
+		      <0x00 0x02b48000 0x00 0x1000>;
+		reg-names = "mpu","dat";
+		interrupts = <GIC_SPI 552 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 553 IRQ_TYPE_LEVEL_HIGH>;
+		interrupt-names = "tx", "rx";
+		dmas = <&main_udmap 0xc404>, <&main_udmap 0x4404>;
+		dma-names = "tx", "rx";
+		clocks = <&k3_clks 213 0>;
+		clock-names = "fck";
+		assigned-clocks = <&k3_clks 213 0>;
+		assigned-clock-parents = <&k3_clks 213 1>;
+		power-domains = <&k3_pds 213 TI_SCI_PD_EXCLUSIVE>;
+		status = "disabled";
+	};
 };
-- 
2.34.1

[PATCH 2/3] arm64: dts: ti: k3-j721s2-main: Add audio_refclk node

[Jayesh Choudhary]

On J721S2 SoC, the AUDIO_REFCLK1 can be used as input to external
peripherals when configured through CTRL_MMR.
Add audio_refclk1 node which would be used as system clock for
audio codec PCM3168A.

Signed-off-by: Jayesh Choudhary <j-choudhary@ti.com>
---
 arch/arm64/boot/dts/ti/k3-j721s2-main.dtsi | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/arm64/boot/dts/ti/k3-j721s2-main.dtsi b/arch/arm64/boot/dts/ti/k3-j721s2-main.dtsi
index 6dee0c573980..e21f6092b3f0 100644
--- a/arch/arm64/boot/dts/ti/k3-j721s2-main.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-j721s2-main.dtsi
@@ -74,6 +74,15 @@ ehrpwm_tbclk: clock-controller@140 {
 			reg = <0x140 0x18>;
 			#clock-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>;
+		};
 	};
 
 	main_ehrpwm0: pwm@3000000 {
-- 
2.34.1

[PATCH 3/3] arm64: dts: ti: k3-j721s2-common-proc-board: Enable analog audio support

[Jayesh Choudhary]

The audio support on J721S2-EVM is using PCM3168A codec
connected to McASP4 serializers.

- Add the nodes for sound-card, audio codec, MAIN_I2C3 and
  McASP4.
- Add pinmux for I2C3, McASP4, AUDIO_EXT_REFCLK1 and
  WKUP_GPIO_0.
- Add necessary GPIO hogs to route the MAIN_I2C3 lines and
  McASP serializer.
- Add idle-state as 1 in mux0 and mux1 to route McASP signals

Signed-off-by: Jayesh Choudhary <j-choudhary@ti.com>
---
 .../dts/ti/k3-j721s2-common-proc-board.dts    | 131 ++++++++++++++++++
 1 file changed, 131 insertions(+)

diff --git a/arch/arm64/boot/dts/ti/k3-j721s2-common-proc-board.dts b/arch/arm64/boot/dts/ti/k3-j721s2-common-proc-board.dts
index e2fc1288ed07..9c6a3515847e 100644
--- a/arch/arm64/boot/dts/ti/k3-j721s2-common-proc-board.dts
+++ b/arch/arm64/boot/dts/ti/k3-j721s2-common-proc-board.dts
@@ -128,6 +128,28 @@ transceiver4: can-phy4 {
 		standby-gpios = <&exp_som 7 GPIO_ACTIVE_HIGH>;
 		mux-states = <&mux1 1>;
 	};
+
+	codec_audio: sound {
+		compatible = "ti,j7200-cpb-audio";
+		model = "j721e-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 {
@@ -195,6 +217,22 @@ J721S2_IOPAD(0x03c, PIN_INPUT, 0) /* (U27) MCASP0_AFSX.MCAN5_RX */
 			J721S2_IOPAD(0x038, PIN_OUTPUT, 0) /* (AB28) MCASP0_ACLKX.MCAN5_TX */
 		>;
 	};
+
+	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 {
@@ -292,6 +330,12 @@ J721S2_WKUP_IOPAD(0x104, PIN_INPUT, 0) /* (N26) MCU_ADC1_AIN6 */
 			J721S2_WKUP_IOPAD(0x108, PIN_INPUT, 0) /* (N27) MCU_ADC1_AIN7 */
 		>;
 	};
+
+	main_i2c3_mux_pins_default: main-i2c3-mux-default-pins {
+		pinctrl-single,pins = <
+			J721S2_WKUP_IOPAD(0x038, PIN_OUTPUT, 7) /* (B27) WKUP_GPIO0_54 */
+		>;
+	};
 };
 
 &wkup_pmx1 {
@@ -367,6 +411,22 @@ exp2: gpio@22 {
 				  "MLB_MUX_SEL", "MCAN_MUX_SEL", "MCASP2/SPI3_MUX_SEL", "PCIe_CLKREQn_MUX_SEL",
 				  "CDCI2_RSTZ", "ENET_EXP_PWRDN", "ENET_EXP_RESETZ", "ENET_I2CMUX_SEL",
 				  "ENET_EXP_SPARE2", "M2PCIE_RTSZ", "USER_INPUT1", "USER_LED1", "USER_LED2";
+
+		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";
+		};
 	};
 };
 
@@ -539,3 +599,74 @@ &main_mcan5 {
 	pinctrl-0 = <&main_mcan5_pins_default>;
 	phys = <&transceiver4>;
 };
+
+&mux0 {
+	idle-state = <0>;
+};
+
+&mux1 {
+	idle-state = <0>;
+};
+
+&exp_som {
+	p03-hog {
+		/* P03 - CANUART_MUX_SEL1 */
+		gpio-hog;
+		gpios = <3 GPIO_ACTIVE_HIGH>;
+		output-high;
+		line-name = "CANUART_MUX_SEL1";
+	};
+};
+
+&k3_clks {
+	/* Confiure 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>;
+
+	exp3: gpio@20 {
+		compatible = "ti,tca6408";
+		reg = <0x20>;
+		gpio-controller;
+		#gpio-cells = <2>;
+	};
+
+	pcm3168a_1: audio-codec@44 {
+		compatible = "ti,pcm3168a";
+		reg = <0x44>;
+		#sound-dai-cells = <1>;
+		reset-gpios = <&exp3 0 GPIO_ACTIVE_LOW>;
+		/* C_AUDIO_REFCLK1 -> MCAN2_RX (Y25) */
+		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 0/3] Enable audio support for J721S2-EVM

[Rob Herring (Arm)]

On Wed, 04 Jun 2025 16:16:53 +0530, Jayesh Choudhary wrote:
> These 3 patches add the support to enable audio on J721S2-EVM.
> 
> This required the i2c-mux support[0] which is now in linux tree.
> 
> Now, this series ***depends upon only one dts change[1]*** to ensure there
> are no dtbs_check warnings (no functional issues):
> "ti,j721e-system-controller.yaml" refers to "ti,am654-ehrpwm-tbclk.yaml"
> for clock-controller nodes, but for audio we need "ti,am62-audio-refclk".
> When scm_conf is "simple-bus", there are no such warnings.
> 
> Test log: https://gist.github.com/Jayesh2000/840c19ef8f9b7f0f75dedd015ccbf98a
> 
> [0]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0fc829dbde9bf1f349631c677a85e08782037ecf
> [1]: https://lore.kernel.org/all/20250603095609.33569-4-j-choudhary@ti.com/
> 
> 
> Jayesh Choudhary (3):
>   arm64: dts: ti: k3-j721s2-main: Add McASP nodes
>   arm64: dts: ti: k3-j721s2-main: Add audio_refclk node
>   arm64: dts: ti: k3-j721s2-common-proc-board: Enable analog audio
>     support
> 
>  .../dts/ti/k3-j721s2-common-proc-board.dts    | 131 ++++++++++++++++++
>  arch/arm64/boot/dts/ti/k3-j721s2-main.dtsi    |  99 +++++++++++++
>  2 files changed, 230 insertions(+)
> 
> --
> 2.34.1
> 
> 
> 


My bot found new DTB warnings on the .dts files added or changed in this
series.

Some warnings may be from an existing SoC .dtsi. Or perhaps the warnings
are fixed by another series. Ultimately, it is up to the platform
maintainer whether these warnings are acceptable or not. No need to reply
unless the platform maintainer has comments.

If you already ran DT checks and didn't see these error(s), then
make sure dt-schema is up to date:

  pip3 install dtschema --upgrade


This patch series was applied (using b4) to base:
 Base: attempting to guess base-commit...
 Base: tags/next-20250604 (best guess, 1/2 blobs matched)

If this is not the correct base, please add 'base-commit' tag
(or use b4 which does this automatically)

New warnings running 'make CHECK_DTBS=y for arch/arm64/boot/dts/ti/' for 20250604104656.38752-1-j-choudhary@ti.com:

arch/arm64/boot/dts/ti/k3-am68-phyboard-izar.dtb: syscon@104000 (ti,j721e-system-controller): clock-controller@42e4: 'assigned-clock-parents', 'assigned-clocks', 'clocks' do not match any of the regexes: '^pinctrl-[0-9]+$'
	from schema $id: http://devicetree.org/schemas/soc/ti/ti,j721e-system-controller.yaml#
arch/arm64/boot/dts/ti/k3-am68-phyboard-izar.dtb: syscon@104000 (ti,j721e-system-controller): clock-controller@42e4:#clock-cells: 1 was expected
	from schema $id: http://devicetree.org/schemas/soc/ti/ti,j721e-system-controller.yaml#
arch/arm64/boot/dts/ti/k3-am68-phyboard-izar.dtb: syscon@104000 (ti,j721e-system-controller): clock-controller@42e4:compatible:0: 'ti,am62-audio-refclk' is not one of ['ti,am654-ehrpwm-tbclk', 'ti,am64-epwm-tbclk', 'ti,am62-epwm-tbclk']
	from schema $id: http://devicetree.org/schemas/soc/ti/ti,j721e-system-controller.yaml#
arch/arm64/boot/dts/ti/k3-am68-sk-base-board.dtb: syscon@104000 (ti,j721e-system-controller): clock-controller@42e4: 'assigned-clock-parents', 'assigned-clocks', 'clocks' do not match any of the regexes: '^pinctrl-[0-9]+$'
	from schema $id: http://devicetree.org/schemas/soc/ti/ti,j721e-system-controller.yaml#
arch/arm64/boot/dts/ti/k3-am68-sk-base-board.dtb: syscon@104000 (ti,j721e-system-controller): clock-controller@42e4:#clock-cells: 1 was expected
	from schema $id: http://devicetree.org/schemas/soc/ti/ti,j721e-system-controller.yaml#
arch/arm64/boot/dts/ti/k3-am68-sk-base-board.dtb: syscon@104000 (ti,j721e-system-controller): clock-controller@42e4:compatible:0: 'ti,am62-audio-refclk' is not one of ['ti,am654-ehrpwm-tbclk', 'ti,am64-epwm-tbclk', 'ti,am62-epwm-tbclk']
	from schema $id: http://devicetree.org/schemas/soc/ti/ti,j721e-system-controller.yaml#
arch/arm64/boot/dts/ti/k3-j721s2-common-proc-board.dtb: syscon@104000 (ti,j721e-system-controller): clock-controller@42e4: 'assigned-clock-parents', 'assigned-clocks', 'clocks' do not match any of the regexes: '^pinctrl-[0-9]+$'
	from schema $id: http://devicetree.org/schemas/soc/ti/ti,j721e-system-controller.yaml#
arch/arm64/boot/dts/ti/k3-j721s2-common-proc-board.dtb: syscon@104000 (ti,j721e-system-controller): clock-controller@42e4:#clock-cells: 1 was expected
	from schema $id: http://devicetree.org/schemas/soc/ti/ti,j721e-system-controller.yaml#
arch/arm64/boot/dts/ti/k3-j721s2-common-proc-board.dtb: syscon@104000 (ti,j721e-system-controller): clock-controller@42e4:compatible:0: 'ti,am62-audio-refclk' is not one of ['ti,am654-ehrpwm-tbclk', 'ti,am64-epwm-tbclk', 'ti,am62-epwm-tbclk']
	from schema $id: http://devicetree.org/schemas/soc/ti/ti,j721e-system-controller.yaml#

Re: (subset) [PATCH 0/3] Enable audio support for J721S2-EVM

[Vignesh Raghavendra]

Hi Jayesh Choudhary,

On Wed, 04 Jun 2025 16:16:53 +0530, Jayesh Choudhary wrote:
> These 3 patches add the support to enable audio on J721S2-EVM.
> 
> This required the i2c-mux support[0] which is now in linux tree.
> 
> Now, this series ***depends upon only one dts change[1]*** to ensure there
> are no dtbs_check warnings (no functional issues):
> "ti,j721e-system-controller.yaml" refers to "ti,am654-ehrpwm-tbclk.yaml"
> for clock-controller nodes, but for audio we need "ti,am62-audio-refclk".
> When scm_conf is "simple-bus", there are no such warnings.
> 
> [...]

I have applied the following to branch ti-k3-dts-next on [1].
Thank you!

[1/3] arm64: dts: ti: k3-j721s2-main: Add McASP nodes
      commit: 56bf596ff9026b616137968102884233c86055d4

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent up the chain during
the next merge window (or sooner if it is a relevant bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/ti/linux.git
--
Vignesh