From fdedfc2109a55ebe408634a8554b91ac8d098052 Mon Sep 17 00:00:00 2001 From: Martin Blumenstingl Date: Sat, 29 Mar 2025 19:58:54 +0100 Subject: [PATCH] arm64: dts: amlogic: axg: 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/20250329185855.854186-7-martin.blumenstingl@googlemail.com Signed-off-by: Neil Armstrong --- arch/arm64/boot/dts/amlogic/meson-axg.dtsi | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/arch/arm64/boot/dts/amlogic/meson-axg.dtsi b/arch/arm64/boot/dts/amlogic/meson-axg.dtsi index a6924d246bb1e..2df143aa77ce3 100644 --- a/arch/arm64/boot/dts/amlogic/meson-axg.dtsi +++ b/arch/arm64/boot/dts/amlogic/meson-axg.dtsi @@ -1164,7 +1164,7 @@ groups = "uart_tx_a", "uart_rx_a"; function = "uart_a"; - bias-disable; + bias-pull-up; }; }; @@ -1182,7 +1182,7 @@ groups = "uart_tx_b_x", "uart_rx_b_x"; function = "uart_b"; - bias-disable; + bias-pull-up; }; }; @@ -1200,7 +1200,7 @@ groups = "uart_tx_b_z", "uart_rx_b_z"; function = "uart_b"; - bias-disable; + bias-pull-up; }; }; @@ -1218,7 +1218,7 @@ groups = "uart_ao_tx_b_z", "uart_ao_rx_b_z"; function = "uart_ao_b_z"; - bias-disable; + bias-pull-up; }; }; @@ -1654,7 +1654,7 @@ groups = "uart_ao_tx_a", "uart_ao_rx_a"; function = "uart_ao_a"; - bias-disable; + bias-pull-up; }; }; @@ -1672,7 +1672,7 @@ groups = "uart_ao_tx_b", "uart_ao_rx_b"; function = "uart_ao_b"; - bias-disable; + bias-pull-up; }; }; -- 2.47.3