Both the R5S and R5C have a MASKROM button connected via saradc.
For both the R5S as the R5C it's described on page 9 of their
respective schematic, identified as 'Recovery'.

Signed-off-by: Diederik de Haas <didi.debian@cknow.org>
---
 .../arm64/boot/dts/rockchip/rk3568-nanopi-r5s.dtsi | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/arm64/boot/dts/rockchip/rk3568-nanopi-r5s.dtsi b/arch/arm64/boot/dts/rockchip/rk3568-nanopi-r5s.dtsi
index f4d042bdd328..e3f44ea4eabe 100644
--- a/arch/arm64/boot/dts/rockchip/rk3568-nanopi-r5s.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3568-nanopi-r5s.dtsi
@@ -25,6 +25,20 @@ chosen: chosen {
 		stdout-path = "serial2:1500000n8";
 	};
 
+	adc-keys {
+		compatible = "adc-keys";
+		io-channels = <&saradc 0>;
+		io-channel-names = "buttons";
+		keyup-threshold-microvolt = <1800000>;
+		poll-interval = <100>;
+
+		button-maskrom {
+			label = "MASKROM";
+			linux,code = <KEY_SETUP>;
+			press-threshold-microvolt = <0>;
+		};
+	};
+
 	hdmi-con {
 		compatible = "hdmi-connector";
 		type = "a";
-- 
2.50.0

On Wed, 16 Jul 2025 10:33:35 +0200, Diederik de Haas wrote:
> Both the R5S and R5C have a MASKROM button connected via saradc.
> For both the R5S as the R5C it's described on page 9 of their
> respective schematic, identified as 'Recovery'.
> 
> 

Applied, thanks!

And added a NanoPi before the "R5S + R5C"

[1/1] arm64: dts: rockchip: Add maskrom button to R5S + R5C
      commit: 07e04c071a35abe12957b575cd1453ccafc02eb6

Best regards,
-- 
Heiko Stuebner <heiko@sntech.de>