[PATCH 0/6] arm64: dts: amlogic: meson-s4-khadas-vim1s: enable LEDs, Keys and Bluetooth

[PATCH 0/6] arm64: dts: amlogic: meson-s4-khadas-vim1s: enable LEDs, Keys and Bluetooth

[Nick Xie]

This series enables various user interfaces and the Bluetooth module
for the Khadas VIM1S board (Amlogic S905Y4).

This builds upon the existing board support to fully enable the
user-facing peripherals.

Summary of changes:
- Enable UART_A and Bluetooth (AP6256)
- Enable PWM_G and the Heartbeat LED
- Enable GPIO-polled Power key
- Enable SARADC and the ADC Function key

Nick Xie (6):
  arm64: dts: amlogic: meson-s4: add UART_A node
  arm64: dts: amlogic: meson-s4-s905y4-khadas-vim1s: enable bluetooth
  arm64: dts: amlogic: meson-s4-s905y4-khadas-vim1s: add PWM LED support
  arm64: dts: amlogic: meson-s4-s905y4-khadas-vim1s: add POWER key
    support
  arm64: dts: amlogic: meson-s4: add internal SARADC controller
  arm64: dts: amlogic: meson-s4-s905y4-khadas-vim1s: add Function key
    support

 .../amlogic/meson-s4-s905y4-khadas-vim1s.dts  | 63 +++++++++++++++++++
 arch/arm64/boot/dts/amlogic/meson-s4.dtsi     | 36 +++++++++++
 2 files changed, 99 insertions(+)

-- 
2.34.1

[PATCH 1/6] arm64: dts: amlogic: meson-s4: add UART_A node

[Nick Xie]

Add the UART_A node and its related pinctrl definitions to the
Meson S4 SoC dtsi.

This interface is typically used for Bluetooth communication on
boards like the Khadas VIM1S.

Signed-off-by: Nick Xie <nick@khadas.com>
---
 arch/arm64/boot/dts/amlogic/meson-s4.dtsi | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/arch/arm64/boot/dts/amlogic/meson-s4.dtsi b/arch/arm64/boot/dts/amlogic/meson-s4.dtsi
index dfc0a30a6e61b..b1d66054a6e87 100644
--- a/arch/arm64/boot/dts/amlogic/meson-s4.dtsi
+++ b/arch/arm64/boot/dts/amlogic/meson-s4.dtsi
@@ -163,6 +163,16 @@ mux {
 					};
 				};
 
+				a_uart_pins: a_uart {
+					mux {
+						groups = "uart_a_tx",
+						       "uart_a_rx",
+						       "uart_a_cts",
+						       "uart_a_rts";
+						function = "uart_a";
+					};
+				};
+
 				i2c0_pins1: i2c0-pins1 {
 					mux {
 						groups = "i2c0_sda",
@@ -814,6 +824,18 @@ mdio0: mdio {
 			};
 		};
 
+		uart_a: serial@fe078000 {
+			compatible = "amlogic,meson-s4-uart",
+				     "amlogic,meson-ao-uart";
+			reg = <0x0 0xfe078000 0x0 0x18>;
+			interrupts = <GIC_SPI 168 IRQ_TYPE_EDGE_RISING>;
+			clocks = <&xtal>, <&clkc_periphs CLKID_UART_A>, <&xtal>;
+			clock-names = "xtal", "pclk", "baud";
+			pinctrl-names = "default";
+			pinctrl-0 = <&a_uart_pins>;
+			status = "disabled";
+		};
+
 		sdio: mmc@fe088000 {
 			compatible = "amlogic,meson-axg-mmc";
 			reg = <0x0 0xfe088000 0x0 0x800>;
-- 
2.34.1

Re: [PATCH 1/6] arm64: dts: amlogic: meson-s4: add UART_A node

[Martin Blumenstingl]

Hi Nick,

On Fri, Jan 23, 2026 at 3:23 AM Nick Xie <nick@khadas.com> wrote:
[...]
> +                               a_uart_pins: a_uart {
> +                                       mux {
> +                                               groups = "uart_a_tx",
> +                                                      "uart_a_rx",
> +                                                      "uart_a_cts",
> +                                                      "uart_a_rts";
> +                                               function = "uart_a";
> +                                       };
> +                               };
Can we please keep the split between rx/tx and rts/cts pins (as we
have it on other SoCs)?
It is likely that many boards follow the same path as Khadas VIM1S
(and Amlogic's reference design). For those boards that aren't it
would be great if they don't have to update meson-s4.dtsi.

>                                 i2c0_pins1: i2c0-pins1 {
>                                         mux {
>                                                 groups = "i2c0_sda",
> @@ -814,6 +824,18 @@ mdio0: mdio {
>                         };
>                 };
>
> +               uart_a: serial@fe078000 {
> +                       compatible = "amlogic,meson-s4-uart",
> +                                    "amlogic,meson-ao-uart";
> +                       reg = <0x0 0xfe078000 0x0 0x18>;
> +                       interrupts = <GIC_SPI 168 IRQ_TYPE_EDGE_RISING>;
> +                       clocks = <&xtal>, <&clkc_periphs CLKID_UART_A>, <&xtal>;
> +                       clock-names = "xtal", "pclk", "baud";
> +                       pinctrl-names = "default";
> +                       pinctrl-0 = <&a_uart_pins>;
For consistency I also prefer if you could move this to
meson-s4-s905y4-khadas-vim1s.dts (patch 2)


Thank you!
Martin

[PATCH 2/6] arm64: dts: amlogic: meson-s4-s905y4-khadas-vim1s: enable bluetooth

[Nick Xie]

The Khadas VIM1S board uses the Ampak AP6256 Wi-Fi/Bluetooth module.
The Bluetooth controller is connected via UART_A and requires the
external 32k clock (LPO).

Enable the UART_A node and add the bluetooth child node to support it.

Signed-off-by: Nick Xie <nick@khadas.com>
---
 .../dts/amlogic/meson-s4-s905y4-khadas-vim1s.dts    | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/arch/arm64/boot/dts/amlogic/meson-s4-s905y4-khadas-vim1s.dts b/arch/arm64/boot/dts/amlogic/meson-s4-s905y4-khadas-vim1s.dts
index 27d0f6134ea9d..041291999bc8c 100644
--- a/arch/arm64/boot/dts/amlogic/meson-s4-s905y4-khadas-vim1s.dts
+++ b/arch/arm64/boot/dts/amlogic/meson-s4-s905y4-khadas-vim1s.dts
@@ -254,6 +254,19 @@ &spicc0 {
 	cs-gpios = <&gpio GPIOX_10 GPIO_ACTIVE_LOW>;
 };
 
+&uart_a {
+	status = "okay";
+	uart-has-rtscts;
+
+	bluetooth {
+		compatible = "brcm,bcm4345c5";
+		shutdown-gpios = <&gpio GPIOX_17 GPIO_ACTIVE_HIGH>;
+		max-speed = <2000000>;
+		clocks = <&sdio_32k>;
+		clock-names = "lpo";
+	};
+};
+
 &uart_b {
 	status = "okay";
 };
-- 
2.34.1

Re: [PATCH 2/6] arm64: dts: amlogic: meson-s4-s905y4-khadas-vim1s: enable bluetooth

[Martin Blumenstingl]

On Fri, Jan 23, 2026 at 3:23 AM Nick Xie <nick@khadas.com> wrote:
>
> The Khadas VIM1S board uses the Ampak AP6256 Wi-Fi/Bluetooth module.
> The Bluetooth controller is connected via UART_A and requires the
> external 32k clock (LPO).
>
> Enable the UART_A node and add the bluetooth child node to support it.
>
> Signed-off-by: Nick Xie <nick@khadas.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>

You can keep my Reviewed-by when updating this patch to include the
pinctrl properties.

[PATCH 3/6] arm64: dts: amlogic: meson-s4-s905y4-khadas-vim1s: add PWM LED support

[Nick Xie]

The Khadas VIM1S board features a white LED connected to the PWM_G
controller (PWM channel 0).

Enable the PWM_G controller and add the pwm-leds node to support
using this LED as a heartbeat indicator.

Signed-off-by: Nick Xie <nick@khadas.com>
---
 .../amlogic/meson-s4-s905y4-khadas-vim1s.dts  | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/arch/arm64/boot/dts/amlogic/meson-s4-s905y4-khadas-vim1s.dts b/arch/arm64/boot/dts/amlogic/meson-s4-s905y4-khadas-vim1s.dts
index 041291999bc8c..4bae6d46defb5 100644
--- a/arch/arm64/boot/dts/amlogic/meson-s4-s905y4-khadas-vim1s.dts
+++ b/arch/arm64/boot/dts/amlogic/meson-s4-s905y4-khadas-vim1s.dts
@@ -6,6 +6,7 @@
 /dts-v1/;
 
 #include "meson-s4.dtsi"
+#include <dt-bindings/leds/common.h>
 
 / {
 	model = "Khadas VIM1S";
@@ -43,6 +44,18 @@ emmc_pwrseq: emmc-pwrseq {
 		reset-gpios = <&gpio GPIOB_9 GPIO_ACTIVE_LOW>;
 	};
 
+	pwm-leds {
+		compatible = "pwm-leds";
+
+		led-1 {
+			color = <LED_COLOR_ID_WHITE>;
+			function = LED_FUNCTION_STATUS;
+			linux,default-trigger = "heartbeat";
+			max-brightness = <255>;
+			pwms = <&pwm_gh 0 30040 0>;
+		};
+	};
+
 	sdio_32k: sdio-32k {
 		compatible = "pwm-clock";
 		#clock-cells = <0>;
@@ -196,6 +209,12 @@ &pwm_ef {
 	pinctrl-names = "default";
 };
 
+&pwm_gh {
+	status = "okay";
+	pinctrl-0 = <&pwm_g_pins1>;
+	pinctrl-names = "default";
+};
+
 &pwm_ij {
 	status = "okay";
 };
-- 
2.34.1

Re: [PATCH 3/6] arm64: dts: amlogic: meson-s4-s905y4-khadas-vim1s: add PWM LED support

[Martin Blumenstingl]

On Fri, Jan 23, 2026 at 3:23 AM Nick Xie <nick@khadas.com> wrote:
>
> The Khadas VIM1S board features a white LED connected to the PWM_G
> controller (PWM channel 0).
>
> Enable the PWM_G controller and add the pwm-leds node to support
> using this LED as a heartbeat indicator.
>
> Signed-off-by: Nick Xie <nick@khadas.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>

[PATCH 4/6] arm64: dts: amlogic: meson-s4-s905y4-khadas-vim1s: add POWER key support

[Nick Xie]

Add the gpio-keys-polled node to support the Power button found on the
Khadas VIM1S board. The button is connected to the GPIOD_8 pin.

Use polled mode instead of gpio-keys because the GPIO interrupt
controller support for Meson S4 SoC is not yet available upstream.

Signed-off-by: Nick Xie <nick@khadas.com>
---
 .../dts/amlogic/meson-s4-s905y4-khadas-vim1s.dts     | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/arm64/boot/dts/amlogic/meson-s4-s905y4-khadas-vim1s.dts b/arch/arm64/boot/dts/amlogic/meson-s4-s905y4-khadas-vim1s.dts
index 4bae6d46defb5..cf65c079e675a 100644
--- a/arch/arm64/boot/dts/amlogic/meson-s4-s905y4-khadas-vim1s.dts
+++ b/arch/arm64/boot/dts/amlogic/meson-s4-s905y4-khadas-vim1s.dts
@@ -6,6 +6,7 @@
 /dts-v1/;
 
 #include "meson-s4.dtsi"
+#include <dt-bindings/input/input.h>
 #include <dt-bindings/leds/common.h>
 
 / {
@@ -44,6 +45,17 @@ emmc_pwrseq: emmc-pwrseq {
 		reset-gpios = <&gpio GPIOB_9 GPIO_ACTIVE_LOW>;
 	};
 
+	gpio-keys-polled {
+		compatible = "gpio-keys-polled";
+		poll-interval = <100>;
+
+		power-button {
+			label = "power";
+			linux,code = <KEY_POWER>;
+			gpios = <&gpio GPIOD_8 GPIO_ACTIVE_LOW>;
+		};
+	};
+
 	pwm-leds {
 		compatible = "pwm-leds";
 
-- 
2.34.1

Re: [PATCH 4/6] arm64: dts: amlogic: meson-s4-s905y4-khadas-vim1s: add POWER key support

[Martin Blumenstingl]

On Fri, Jan 23, 2026 at 3:23 AM Nick Xie <nick@khadas.com> wrote:
>
> Add the gpio-keys-polled node to support the Power button found on the
> Khadas VIM1S board. The button is connected to the GPIOD_8 pin.
>
> Use polled mode instead of gpio-keys because the GPIO interrupt
> controller support for Meson S4 SoC is not yet available upstream.
>
> Signed-off-by: Nick Xie <nick@khadas.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>

[PATCH 5/6] arm64: dts: amlogic: meson-s4: add internal SARADC controller

[Nick Xie]

Add the SARADC (Successive Approximation Register ADC) controller
node to the Meson S4 SoC dtsi.

Signed-off-by: Nick Xie <nick@khadas.com>
---
 arch/arm64/boot/dts/amlogic/meson-s4.dtsi | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/arm64/boot/dts/amlogic/meson-s4.dtsi b/arch/arm64/boot/dts/amlogic/meson-s4.dtsi
index b1d66054a6e87..cd768f9f4db80 100644
--- a/arch/arm64/boot/dts/amlogic/meson-s4.dtsi
+++ b/arch/arm64/boot/dts/amlogic/meson-s4.dtsi
@@ -77,6 +77,20 @@ pwrc: power-controller {
 		};
 	};
 
+	saradc: adc@fe026000 {
+		compatible = "amlogic,meson-g12a-saradc",
+			     "amlogic,meson-saradc";
+		reg = <0x0 0xfe026000 0x0 0x48>;
+		#io-channel-cells = <1>;
+		interrupts = <GIC_SPI 181 IRQ_TYPE_EDGE_RISING>;
+		clocks = <&xtal>,
+			 <&clkc_periphs CLKID_SAR_ADC>,
+			 <&clkc_periphs CLKID_SARADC>,
+			 <&clkc_periphs CLKID_SARADC_SEL>;
+		clock-names = "clkin", "core", "adc_clk", "adc_sel";
+		status = "disabled";
+	};
+
 	soc {
 		compatible = "simple-bus";
 		#address-cells = <2>;
-- 
2.34.1

Re: [PATCH 5/6] arm64: dts: amlogic: meson-s4: add internal SARADC controller

[Martin Blumenstingl]

Hi Nick,

On Fri, Jan 23, 2026 at 3:23 AM Nick Xie <nick@khadas.com> wrote:
[...]
> +       saradc: adc@fe026000 {
> +               compatible = "amlogic,meson-g12a-saradc",
> +                            "amlogic,meson-saradc";
It seems that the engineers at Amlogic are constantly updating the SARADC core.
To avoid any problems in the future, can you please add a new
compatible string for the s4-saradc?
For reference you can take a look at:
- commit e415a1659ec9 ("iio: adc: meson-saradc: add support for Meson
G12A") which added the g12a compatible string to the driver (note that
meson_sar_adc_gxl_param since then has been replaced by
meson_sar_adc_g12a_param - you can re-use the latter)
- commit b2729cdf2bc0 ("dt-bindings: iio: adc: amlogic,meson-saradc:
Add GXLX SoC compatible") which documented a new compatible string in
the dt-bindings

I think it is best to do this in a separate series.

In case we discover anything that needs changing in the SARADC driver in future:
Having a dedicated compatible string means we can just update the
driver and be done with it.
One example where this has happened for G12A is commit 48dc1abde015
("iio: adc: meson-saradc: Disable BL30 integration on G12A and newer
SoCs").


Thank you!
Martin

[PATCH 6/6] arm64: dts: amlogic: meson-s4-s905y4-khadas-vim1s: add Function key support

[Nick Xie]

Enable the SARADC controller and add the adc-keys node to support
the Function key found on the Khadas VIM1S board.

Signed-off-by: Nick Xie <nick@khadas.com>
---
 .../amlogic/meson-s4-s905y4-khadas-vim1s.dts  | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/arch/arm64/boot/dts/amlogic/meson-s4-s905y4-khadas-vim1s.dts b/arch/arm64/boot/dts/amlogic/meson-s4-s905y4-khadas-vim1s.dts
index cf65c079e675a..2fa2ed941cb98 100644
--- a/arch/arm64/boot/dts/amlogic/meson-s4-s905y4-khadas-vim1s.dts
+++ b/arch/arm64/boot/dts/amlogic/meson-s4-s905y4-khadas-vim1s.dts
@@ -40,6 +40,20 @@ secmon_reserved: secmon@5000000 {
 		};
 	};
 
+	adc-keys {
+		compatible = "adc-keys";
+		io-channels = <&saradc 0>;
+		io-channel-names = "buttons";
+		keyup-threshold-microvolt = <1710000>;
+		poll-interval = <100>;
+
+		button-function {
+			label = "Function";
+			linux,code = <KEY_FN>;
+			press-threshold-microvolt = <10000>;
+		};
+	};
+
 	emmc_pwrseq: emmc-pwrseq {
 		compatible = "mmc-pwrseq-emmc";
 		reset-gpios = <&gpio GPIOB_9 GPIO_ACTIVE_LOW>;
@@ -278,6 +292,11 @@ brcmf: wifi@1 {
 	};
 };
 
+&saradc {
+	status = "okay";
+	vref-supply = <&vddio_ao1v8>;
+};
+
 &spicc0 {
 	status = "okay";
 	pinctrl-names = "default";
-- 
2.34.1

Re: [PATCH 6/6] arm64: dts: amlogic: meson-s4-s905y4-khadas-vim1s: add Function key support

[Martin Blumenstingl]

On Fri, Jan 23, 2026 at 3:23 AM Nick Xie <nick@khadas.com> wrote:
>
> Enable the SARADC controller and add the adc-keys node to support
> the Function key found on the Khadas VIM1S board.
>
> Signed-off-by: Nick Xie <nick@khadas.com>
Applying this patch will require the previous one to be updated with
the compatible string.
Even when the compatible string changes (in meson-s4.dtsi) this patch
will still be good, so please add my:
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>