[PATCH v2 0/3] Khadas VIM4 PWM status LED support

[PATCH v2 0/3] 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 moves the xtal-clk node to restore alphabetical ordering among
root node children.

Patch 3 enables the pwm_ao_cd controller on the VIM4 and adds a
pwm-leds node with a heartbeat trigger.

Signed-off-by: Ronald Claveau <linux-kernel-dev@aliel.fr>
---
Changes in v2:
- PATCH 2-3: Create a new patch specific to the reordering action.
             According to Neil's review.
- Link to v1: https://lore.kernel.org/r/20260512-add-kvim4-sysled-v1-0-7178719a43e7@aliel.fr

---
Ronald Claveau (3):
      arm64: dts: amlogic: t7: Fix pwm_ao_c pinmux definitions
      arm64: dts: amlogic: t7: khadas-vim4: reorder root node
      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>

[PATCH v2 1/3] 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")
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
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

[PATCH v2 2/3] arm64: dts: amlogic: t7: khadas-vim4: reorder root node

[Ronald Claveau via B4 Relay]

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

Move the xtal-clk node to restore alphabetical ordering.

Signed-off-by: Ronald Claveau <linux-kernel-dev@aliel.fr>
---
 .../boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts     | 14 +++++++-------
 1 file changed, 7 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..fd1b983354a01 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";
@@ -155,6 +148,13 @@ 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 {

-- 
2.49.0

[PATCH v2 3/3] 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.

Signed-off-by: Ronald Claveau <linux-kernel-dev@aliel.fr>
---
 .../boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts   | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

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 fd1b983354a01..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
@@ -53,6 +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";
@@ -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

Re: [PATCH v2 2/3] arm64: dts: amlogic: t7: khadas-vim4: reorder root node

[Neil Armstrong]

On 5/13/26 12:43, Ronald Claveau via B4 Relay wrote:
> From: Ronald Claveau <linux-kernel-dev@aliel.fr>
> 
> Move the xtal-clk node to restore alphabetical ordering.
> 
> Signed-off-by: Ronald Claveau <linux-kernel-dev@aliel.fr>
> ---
>   .../boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts     | 14 +++++++-------
>   1 file changed, 7 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..fd1b983354a01 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";
> @@ -155,6 +148,13 @@ 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 {
> 

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

Thanks,
Neil

Re: [PATCH v2 3/3] arm64: dts: amlogic: t7: khadas-vim4: add PWM-driven status LED

[Neil Armstrong]

On 5/13/26 12:43, 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.
> 
> Signed-off-by: Ronald Claveau <linux-kernel-dev@aliel.fr>
> ---
>   .../boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts   | 16 ++++++++++++++++
>   1 file changed, 16 insertions(+)
> 
> 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 fd1b983354a01..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
> @@ -53,6 +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";
> @@ -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";
> 

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

Thanks,
Neil

Re: (subset) [PATCH v2 0/3] Khadas VIM4 PWM status LED support

[Neil Armstrong]

Hi,

On Wed, 13 May 2026 12:43:52 +0200, Ronald Claveau 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.
> 
> [...]

Thanks, Applied to https://git.kernel.org/pub/scm/linux/kernel/git/amlogic/linux.git (v7.2/arm64-dt)

[2/3] arm64: dts: amlogic: t7: khadas-vim4: reorder root node
      https://git.kernel.org/amlogic/c/308e24fb9571be23aaee2e2a5de3da6f5cb3b029
[3/3] arm64: dts: amlogic: t7: khadas-vim4: add PWM-driven status LED
      https://git.kernel.org/amlogic/c/2bb37dc2976dc980a05ca93f529ff9977a24875d

These changes has been applied on the intermediate git tree [1].

The v7.2/arm64-dt branch will then be sent via a formal Pull Request to the Linux SoC maintainers
for inclusion in their intermediate git branches in order to be sent to Linus during
the next merge window, or sooner if it's a set of fixes.

In the cases of fixes, those will be merged in the current release candidate
kernel and as soon they appear on the Linux master branch they will be
backported to the previous Stable and Long-Stable kernels [2].

The intermediate git branches are merged daily in the linux-next tree [3],
people are encouraged testing these pre-release kernels and report issues on the
relevant mailing-lists.

If problems are discovered on those changes, please submit a signed-off-by revert
patch followed by a corrective changeset.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/amlogic/linux.git
[2] https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
[3] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git

-- 
Neil