From 7db1068a5eedc419347a30dc81a25e3342fbbc10 Mon Sep 17 00:00:00 2001 From: Martin Blumenstingl Date: Sat, 29 Mar 2025 19:58:50 +0100 Subject: [PATCH] ARM: dts: amlogic: meson8b: enable UART RX and TX pull up by default Some boards have noise on the UART RX line when the UART pins are not connected to another device (such as an USB UART adapter). This can be addressed by using a pull up resistor. Not all boards may provide such a pull up resistor on the PCB so enable the SoC's pull-up on the UART RX and TX pads by default. This matches the default (from u-boot or SoC hardware) state for the pinmux configuration on these pads. Signed-off-by: Martin Blumenstingl Reviewed-by: Neil Armstrong Link: https://lore.kernel.org/r/20250329185855.854186-3-martin.blumenstingl@googlemail.com Signed-off-by: Neil Armstrong --- arch/arm/boot/dts/amlogic/meson8b.dtsi | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm/boot/dts/amlogic/meson8b.dtsi b/arch/arm/boot/dts/amlogic/meson8b.dtsi index 0876611ce26a8..faf09f77c6056 100644 --- a/arch/arm/boot/dts/amlogic/meson8b.dtsi +++ b/arch/arm/boot/dts/amlogic/meson8b.dtsi @@ -368,7 +368,7 @@ mux { groups = "uart_tx_ao_a", "uart_rx_ao_a"; function = "uart_ao"; - bias-disable; + bias-pull-up; }; }; @@ -521,7 +521,7 @@ groups = "uart_tx_b0", "uart_rx_b0"; function = "uart_b"; - bias-disable; + bias-pull-up; }; }; -- 2.39.5