[PATCH 0/2] Khadas VIM4 PWM status LED support

[PATCH 0/2] Khadas VIM4 PWM status LED support

[Ronald Claveau via B4 Relay]

This series adds support for the PWM-driven status LED on the Khadas
VIM4 board (Amlogic T7).

The VIM4 exposes a heartbeat LED wired to the PWM_AO_C output, routed
through pin group pwm_ao_c_d. Before wiring it up in the board DTS,
the SoC pinmux definitions had to be corrected: the original
pwm_ao_c node was conflating two distinct pin groups (pwm_ao_c_d and
pwm_ao_c_e) into a single ambiguous entry.

Patch 1 fixes the pwm_ao_c pinmux entries in the T7 DTSI by splitting
them into two properly named nodes. Neither alternate is in use yet,
so there is no functional impact on existing boards.

Patch 2 enables the pwm_ao_cd controller on the VIM4 and adds a
pwm-leds node with a heartbeat trigger. The xtal-clk node is also
moved to restore alphabetical ordering among root node children.

Signed-off-by: Ronald Claveau <linux-kernel-dev@aliel.fr>
---
Ronald Claveau (2):
      arm64: dts: amlogic: t7: Fix pwm_ao_c pinmux definitions
      arm64: dts: amlogic: t7: khadas-vim4: add PWM-driven status LED

 .../dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts  | 30 +++++++++++++++++-----
 arch/arm64/boot/dts/amlogic/amlogic-t7.dtsi        | 12 +++++++--
 2 files changed, 33 insertions(+), 9 deletions(-)
---
base-commit: 31f32e8cdf59291e467250dfc57d1a8c718f63d2
change-id: 20260512-add-kvim4-sysled-8cc159524561

Best regards,
-- 
Ronald Claveau <linux-kernel-dev@aliel.fr>



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[PATCH 1/2] arm64: dts: amlogic: t7: Fix pwm_ao_c pinmux definitions

[Ronald Claveau via B4 Relay]

From: Ronald Claveau <linux-kernel-dev@aliel.fr>

The pwm_ao_c pin node was incomplete: it was missing the group name
suffix, conflating two distinct pin groups (pwm_ao_c_d and pwm_ao_c_e)
into a single, ambiguous entry.

Split the node into two separate pinmux entries:
  - pwm_ao_c_d_pins: uses group "pwm_ao_c_d"
  - pwm_ao_c_e_pins: uses group "pwm_ao_c_e"

Both alternate pins are not yet referenced by any peripheral node,
so this has no functional impact on existing boards. No backport needed.

Fixes: ee6e05a49b93 ("arm64: dts: amlogic: t7: Add PWM pinctrl nodes")
Signed-off-by: Ronald Claveau <linux-kernel-dev@aliel.fr>
---
 arch/arm64/boot/dts/amlogic/amlogic-t7.dtsi | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/boot/dts/amlogic/amlogic-t7.dtsi b/arch/arm64/boot/dts/amlogic/amlogic-t7.dtsi
index 7fe72c94ed623..62f6b9baad28b 100644
--- a/arch/arm64/boot/dts/amlogic/amlogic-t7.dtsi
+++ b/arch/arm64/boot/dts/amlogic/amlogic-t7.dtsi
@@ -400,9 +400,17 @@ mux {
 					};
 				};
 
-				pwm_ao_c_pins: pwm-ao-c {
+				pwm_ao_c_d_pins: pwm-ao-c-d {
 					mux {
-						groups = "pwm_ao_c";
+						groups = "pwm_ao_c_d";
+						function = "pwm_ao_c";
+						bias-disable;
+					};
+				};
+
+				pwm_ao_c_e_pins: pwm-ao-c-e {
+					mux {
+						groups = "pwm_ao_c_e";
 						function = "pwm_ao_c";
 						bias-disable;
 					};

-- 
2.49.0



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[PATCH 2/2] arm64: dts: amlogic: t7: khadas-vim4: add PWM-driven status LED

[Ronald Claveau via B4 Relay]

From: Ronald Claveau <linux-kernel-dev@aliel.fr>

The VIM4 board exposes a status LED wired to the PWM_AO_C_D output.
Enable the pwm_ao_cd controller with its pinmux, and declare a
pwm-leds node with a heartbeat trigger.

Also, move the xtal-clk node to restore alphabetical ordering.

Signed-off-by: Ronald Claveau <linux-kernel-dev@aliel.fr>
---
 .../dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts  | 30 +++++++++++++++++-----
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
index 69d6118ba57e7..c41525a34b721 100644
--- a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
+++ b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
@@ -45,13 +45,6 @@ secmon_reserved_bl32: secmon@5300000 {
 		};
 	};
 
-	xtal: xtal-clk {
-		compatible = "fixed-clock";
-		clock-frequency = <24000000>;
-		clock-output-names = "xtal";
-		#clock-cells = <0>;
-	};
-
 	dc_in: regulator-dc-in {
 		compatible = "regulator-fixed";
 		regulator-name = "DC_IN";
@@ -60,6 +53,16 @@ dc_in: regulator-dc-in {
 		regulator-always-on;
 	};
 
+	pwm-leds {
+		compatible = "pwm-leds";
+
+		status {
+			linux,default-trigger="heartbeat";
+			max-brightness = <255>;
+			pwms = <&pwm_ao_cd 0 30040 0>;
+		};
+	};
+
 	sd_3v3: regulator-sdcard-3v3 {
 		compatible = "regulator-fixed";
 		regulator-name = "SD_3V3";
@@ -155,6 +158,13 @@ wifi32k: wifi32k {
 		clock-frequency = <32768>;
 			pwms = <&pwm_ab 0 30518 0>;
 	};
+
+	xtal: xtal-clk {
+		compatible = "fixed-clock";
+		clock-frequency = <24000000>;
+		clock-output-names = "xtal";
+		#clock-cells = <0>;
+	};
 };
 
 &pwm_ab {
@@ -163,6 +173,12 @@ &pwm_ab {
 	pinctrl-names = "default";
 };
 
+&pwm_ao_cd {
+	status = "okay";
+	pinctrl-0 = <&pwm_ao_c_d_pins>;
+	pinctrl-names = "default";
+};
+
 /* SDIO */
 &sd_emmc_a {
 	status = "okay";

-- 
2.49.0



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Re: [PATCH 1/2] arm64: dts: amlogic: t7: Fix pwm_ao_c pinmux definitions

[Neil Armstrong]

On 5/12/26 19:47, Ronald Claveau via B4 Relay wrote:
> From: Ronald Claveau <linux-kernel-dev@aliel.fr>
> 
> The pwm_ao_c pin node was incomplete: it was missing the group name
> suffix, conflating two distinct pin groups (pwm_ao_c_d and pwm_ao_c_e)
> into a single, ambiguous entry.
> 
> Split the node into two separate pinmux entries:
>    - pwm_ao_c_d_pins: uses group "pwm_ao_c_d"
>    - pwm_ao_c_e_pins: uses group "pwm_ao_c_e"
> 
> Both alternate pins are not yet referenced by any peripheral node,
> so this has no functional impact on existing boards. No backport needed.
> 
> Fixes: ee6e05a49b93 ("arm64: dts: amlogic: t7: Add PWM pinctrl nodes")
> Signed-off-by: Ronald Claveau <linux-kernel-dev@aliel.fr>
> ---
>   arch/arm64/boot/dts/amlogic/amlogic-t7.dtsi | 12 ++++++++++--
>   1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/amlogic/amlogic-t7.dtsi b/arch/arm64/boot/dts/amlogic/amlogic-t7.dtsi
> index 7fe72c94ed623..62f6b9baad28b 100644
> --- a/arch/arm64/boot/dts/amlogic/amlogic-t7.dtsi
> +++ b/arch/arm64/boot/dts/amlogic/amlogic-t7.dtsi
> @@ -400,9 +400,17 @@ mux {
>   					};
>   				};
>   
> -				pwm_ao_c_pins: pwm-ao-c {
> +				pwm_ao_c_d_pins: pwm-ao-c-d {
>   					mux {
> -						groups = "pwm_ao_c";
> +						groups = "pwm_ao_c_d";
> +						function = "pwm_ao_c";
> +						bias-disable;
> +					};
> +				};
> +
> +				pwm_ao_c_e_pins: pwm-ao-c-e {
> +					mux {
> +						groups = "pwm_ao_c_e";
>   						function = "pwm_ao_c";
>   						bias-disable;
>   					};
> 

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

I'll squash it on the old commit.

Thanks,
Neil

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Re: [PATCH 2/2] arm64: dts: amlogic: t7: khadas-vim4: add PWM-driven status LED

[Neil Armstrong]

On 5/12/26 19:47, Ronald Claveau via B4 Relay wrote:
> From: Ronald Claveau <linux-kernel-dev@aliel.fr>
> 
> The VIM4 board exposes a status LED wired to the PWM_AO_C_D output.
> Enable the pwm_ao_cd controller with its pinmux, and declare a
> pwm-leds node with a heartbeat trigger.
> 
> Also, move the xtal-clk node to restore alphabetical ordering.

Please send a separate patch for that

> 
> Signed-off-by: Ronald Claveau <linux-kernel-dev@aliel.fr>
> ---
>   .../dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts  | 30 +++++++++++++++++-----
>   1 file changed, 23 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
> index 69d6118ba57e7..c41525a34b721 100644
> --- a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
> +++ b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
> @@ -45,13 +45,6 @@ secmon_reserved_bl32: secmon@5300000 {
>   		};
>   	};
>   
> -	xtal: xtal-clk {
> -		compatible = "fixed-clock";
> -		clock-frequency = <24000000>;
> -		clock-output-names = "xtal";
> -		#clock-cells = <0>;
> -	};
> -
>   	dc_in: regulator-dc-in {
>   		compatible = "regulator-fixed";
>   		regulator-name = "DC_IN";
> @@ -60,6 +53,16 @@ dc_in: regulator-dc-in {
>   		regulator-always-on;
>   	};
>   
> +	pwm-leds {
> +		compatible = "pwm-leds";
> +
> +		status {
> +			linux,default-trigger="heartbeat";
> +			max-brightness = <255>;
> +			pwms = <&pwm_ao_cd 0 30040 0>;
> +		};
> +	};
> +
>   	sd_3v3: regulator-sdcard-3v3 {
>   		compatible = "regulator-fixed";
>   		regulator-name = "SD_3V3";
> @@ -155,6 +158,13 @@ wifi32k: wifi32k {
>   		clock-frequency = <32768>;
>   			pwms = <&pwm_ab 0 30518 0>;
>   	};
> +
> +	xtal: xtal-clk {
> +		compatible = "fixed-clock";
> +		clock-frequency = <24000000>;
> +		clock-output-names = "xtal";
> +		#clock-cells = <0>;
> +	};
>   };
>   
>   &pwm_ab {
> @@ -163,6 +173,12 @@ &pwm_ab {
>   	pinctrl-names = "default";
>   };
>   
> +&pwm_ao_cd {
> +	status = "okay";
> +	pinctrl-0 = <&pwm_ao_c_d_pins>;
> +	pinctrl-names = "default";
> +};
> +
>   /* SDIO */
>   &sd_emmc_a {
>   	status = "okay";
> 


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Re: [PATCH 0/2] Khadas VIM4 PWM status LED support

[Neil Armstrong]

On 5/12/26 19:47, Ronald Claveau via B4 Relay wrote:
> This series adds support for the PWM-driven status LED on the Khadas
> VIM4 board (Amlogic T7).
> 
> The VIM4 exposes a heartbeat LED wired to the PWM_AO_C output, routed
> through pin group pwm_ao_c_d. Before wiring it up in the board DTS,
> the SoC pinmux definitions had to be corrected: the original
> pwm_ao_c node was conflating two distinct pin groups (pwm_ao_c_d and
> pwm_ao_c_e) into a single ambiguous entry.
> 
> Patch 1 fixes the pwm_ao_c pinmux entries in the T7 DTSI by splitting
> them into two properly named nodes. Neither alternate is in use yet,
> so there is no functional impact on existing boards.
> 
> Patch 2 enables the pwm_ao_cd controller on the VIM4 and adds a
> pwm-leds node with a heartbeat trigger. The xtal-clk node is also
> moved to restore alphabetical ordering among root node children.
> 
> Signed-off-by: Ronald Claveau <linux-kernel-dev@aliel.fr>
> ---
> Ronald Claveau (2):
>        arm64: dts: amlogic: t7: Fix pwm_ao_c pinmux definitions
>        arm64: dts: amlogic: t7: khadas-vim4: add PWM-driven status LED
> 
>   .../dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts  | 30 +++++++++++++++++-----
>   arch/arm64/boot/dts/amlogic/amlogic-t7.dtsi        | 12 +++++++--
>   2 files changed, 33 insertions(+), 9 deletions(-)
> ---
> base-commit: 31f32e8cdf59291e467250dfc57d1a8c718f63d2
> change-id: 20260512-add-kvim4-sysled-8cc159524561
> 
> Best regards,

Squashed patch 1 on ee6e05a49b93 ("arm64: dts: amlogic: t7: Add PWM pinctrl nodes")

Neil

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Re: [PATCH 2/2] arm64: dts: amlogic: t7: khadas-vim4: add PWM-driven status LED

[Ronald Claveau]

On 5/13/26 10:05 AM, Neil Armstrong wrote:
> On 5/12/26 19:47, Ronald Claveau via B4 Relay wrote:
>> From: Ronald Claveau <linux-kernel-dev@aliel.fr>
>>
>> The VIM4 board exposes a status LED wired to the PWM_AO_C_D output.
>> Enable the pwm_ao_cd controller with its pinmux, and declare a
>> pwm-leds node with a heartbeat trigger.
>>
>> Also, move the xtal-clk node to restore alphabetical ordering.
> 
> Please send a separate patch for that
> 

Thanks for your review, I will add a new patch.

>>
>> Signed-off-by: Ronald Claveau <linux-kernel-dev@aliel.fr>
>> ---
>>   .../dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts  | 30 ++++++++++++
>> +++++-----
>>   1 file changed, 23 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-
>> vim4.dts b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
>> index 69d6118ba57e7..c41525a34b721 100644
>> --- a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
>> +++ b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
>> @@ -45,13 +45,6 @@ secmon_reserved_bl32: secmon@5300000 {
>>           };
>>       };
>>   -    xtal: xtal-clk {
>> -        compatible = "fixed-clock";
>> -        clock-frequency = <24000000>;
>> -        clock-output-names = "xtal";
>> -        #clock-cells = <0>;
>> -    };
>> -
>>       dc_in: regulator-dc-in {
>>           compatible = "regulator-fixed";
>>           regulator-name = "DC_IN";
>> @@ -60,6 +53,16 @@ dc_in: regulator-dc-in {
>>           regulator-always-on;
>>       };
>>   +    pwm-leds {
>> +        compatible = "pwm-leds";
>> +
>> +        status {
>> +            linux,default-trigger="heartbeat";
>> +            max-brightness = <255>;
>> +            pwms = <&pwm_ao_cd 0 30040 0>;
>> +        };
>> +    };
>> +
>>       sd_3v3: regulator-sdcard-3v3 {
>>           compatible = "regulator-fixed";
>>           regulator-name = "SD_3V3";
>> @@ -155,6 +158,13 @@ wifi32k: wifi32k {
>>           clock-frequency = <32768>;
>>               pwms = <&pwm_ab 0 30518 0>;
>>       };
>> +
>> +    xtal: xtal-clk {
>> +        compatible = "fixed-clock";
>> +        clock-frequency = <24000000>;
>> +        clock-output-names = "xtal";
>> +        #clock-cells = <0>;
>> +    };
>>   };
>>     &pwm_ab {
>> @@ -163,6 +173,12 @@ &pwm_ab {
>>       pinctrl-names = "default";
>>   };
>>   +&pwm_ao_cd {
>> +    status = "okay";
>> +    pinctrl-0 = <&pwm_ao_c_d_pins>;
>> +    pinctrl-names = "default";
>> +};
>> +
>>   /* SDIO */
>>   &sd_emmc_a {
>>       status = "okay";
>>
> 


-- 
Best regards,
Ronald

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Re: [PATCH 1/2] arm64: dts: amlogic: t7: Fix pwm_ao_c pinmux definitions

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The commit provides an incomplete fix by resolving missing pin group suffixes for `pwm_ao_c` but overlooking identical bugs for `pwm_ao_g`, `pwm_ao_h`, and `pwm_vs` in the same device tree file.
--

commit 45b298237b81cf91a3c02cc08237c80e6356d308
Author: Ronald Claveau <linux-kernel-dev@aliel.fr>

arm64: dts: amlogic: t7: Fix pwm_ao_c pinmux definitions

The pwm_ao_c pin node was incomplete: it was missing the group name
suffix, conflating two distinct pin groups (pwm_ao_c_d and pwm_ao_c_e)
into a single, ambiguous entry.

> diff --git a/arch/arm64/boot/dts/amlogic/amlogic-t7.dtsi b/arch/arm64/boot/dts/amlogic/amlogic-t7.dtsi
> index 7fe72c94ed623..62f6b9baad28b 100644
> --- a/arch/arm64/boot/dts/amlogic/amlogic-t7.dtsi
> +++ b/arch/arm64/boot/dts/amlogic/amlogic-t7.dtsi
> @@ -400,9 +400,17 @@ mux {
>  					};
>  				};
>  
> -				pwm_ao_c_pins: pwm-ao-c {
> +				pwm_ao_c_d_pins: pwm-ao-c-d {
>  					mux {
> -						groups = "pwm_ao_c";
> +						groups = "pwm_ao_c_d";

Should we also fix the regressions for pwm_ao_g, pwm_ao_h, and pwm_vs in
this commit?

In this same device tree file, pwm_ao_g_pins, pwm_ao_h_pins, and pwm_vs_pins
are defined using the same generic string pattern:

arch/arm64/boot/dts/amlogic/amlogic-t7.dtsi:
				pwm_ao_g_pins: pwm-ao-g {
					mux {
						groups = "pwm_ao_g";
						function = "pwm_ao_g";
						bias-disable;
					};
				};

In drivers/pinctrl/meson/pinctrl-amlogic-t7.c, these generic groups do not
exist as valid pin arrays. The driver only defines suffixed variants like
pwm_ao_g_d11, pwm_ao_g_d7, pwm_ao_g_e, pwm_ao_h_d5, pwm_ao_h_d10, pwm_vs_y,
and pwm_vs_h.

If any future or out-of-tree board tries to use these existing nodes, won't
it result in a pinctrl lookup failure at runtime?

> +						function = "pwm_ao_c";
> +						bias-disable;
> +					};
> +				};
> +
> +				pwm_ao_c_e_pins: pwm-ao-c-e {
> +					mux {
> +						groups = "pwm_ao_c_e";
>  						function = "pwm_ao_c";
>  						bias-disable;
>  					};

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260512-add-kvim4-sysled-v1-0-7178719a43e7@aliel.fr?part=1

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Re: [PATCH 2/2] arm64: dts: amlogic: t7: khadas-vim4: add PWM-driven status LED

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] The child node of `pwm-leds` is named `status`, which violates the DT schema bindings for PWM LEDs.
--

commit 4d1f2b73cb8a598488da21baaa8d88280487e6f6
Author: Ronald Claveau <linux-kernel-dev@aliel.fr>

arm64: dts: amlogic: t7: khadas-vim4: add PWM-driven status LED

This commit adds a new pwm-leds node with a heartbeat trigger to the VIM4
board devicetree. It also enables the pwm_ao_cd controller and reorders the
xtal-clk node.

> diff --git a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
> index 69d6118ba57e7..c41525a34b721 100644
> --- a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
> +++ b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
[ ... ]
> @@ -60,6 +53,16 @@ dc_in: regulator-dc-in {
>  		regulator-always-on;
>  	};
>  
> +	pwm-leds {
> +		compatible = "pwm-leds";
> +
> +		status {

Will this child node name trigger a devicetree schema validation warning?

The PWM LEDs device tree binding schema restricts child node names using a
pattern property. It expects child nodes to match the regular expression
^led(-[0-9a-f]+)?$.

Since this node is named status, will dtbs_check treat it as an invalid
additional node?

> +			linux,default-trigger="heartbeat";
> +			max-brightness = <255>;
> +			pwms = <&pwm_ao_cd 0 30040 0>;
> +		};
> +	};

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260512-add-kvim4-sysled-v1-0-7178719a43e7@aliel.fr?part=2

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