From a47d29eae229e62c4bf6f6d694d62ab7ccf4d2fe Mon Sep 17 00:00:00 2001
From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Date: Sat, 29 Mar 2025 19:58:51 +0100
Subject: [PATCH 11/50] FROMGIT(6.16): arm64: dts: amlogic: gxbb: 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 <martin.blumenstingl@googlemail.com>
---
 arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi b/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi
index 6c134592c7bb..f69923da07fe 100644
--- a/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi
+++ b/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi
@@ -105,7 +105,7 @@ uart_ao_a_pins: uart_ao_a {
 			mux {
 				groups = "uart_tx_ao_a", "uart_rx_ao_a";
 				function = "uart_ao";
-				bias-disable;
+				bias-pull-up;
 			};
 		};
 
@@ -122,7 +122,7 @@ uart_ao_b_pins: uart_ao_b {
 			mux {
 				groups = "uart_tx_ao_b", "uart_rx_ao_b";
 				function = "uart_ao_b";
-				bias-disable;
+				bias-pull-up;
 			};
 		};
 
@@ -520,7 +520,7 @@ mux {
 				groups = "uart_tx_a",
 				       "uart_rx_a";
 				function = "uart_a";
-				bias-disable;
+				bias-pull-up;
 			};
 		};
 
@@ -538,7 +538,7 @@ mux {
 				groups = "uart_tx_b",
 				       "uart_rx_b";
 				function = "uart_b";
-				bias-disable;
+				bias-pull-up;
 			};
 		};
 
@@ -556,7 +556,7 @@ mux {
 				groups = "uart_tx_c",
 				       "uart_rx_c";
 				function = "uart_c";
-				bias-disable;
+				bias-pull-up;
 			};
 		};
 
-- 
2.34.1

