[PATCH] arm64: dts: rockchip: rk3328: Fix UART pull-ups

[PATCH] arm64: dts: rockchip: rk3328: Fix UART pull-ups

[Chen-Yu Tsai]

From: Chen-Yu Tsai <wens@csie.org>

For UARTs, the local pull-ups should be on the RX pin, not the TX pin.
UARTs transmit active-low, so a disconnected RX pin should be pulled
high instead of left floating to prevent noise being interpreted as
transmissions.

This gets rid of bogus sysrq events when the UART console is not
connected.

Fixes: 52e02d377a72 ("arm64: dts: rockchip: add core dtsi file for RK3328 SoCs")
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
 arch/arm64/boot/dts/rockchip/rk3328.dtsi | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/boot/dts/rockchip/rk3328.dtsi b/arch/arm64/boot/dts/rockchip/rk3328.dtsi
index 521c4678ec35..1e3aa6acbc11 100644
--- a/arch/arm64/boot/dts/rockchip/rk3328.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3328.dtsi
@@ -1265,8 +1265,8 @@ otp_out: otp-out {
 
 		uart0 {
 			uart0_xfer: uart0-xfer {
-				rockchip,pins = <1 RK_PB1 1 &pcfg_pull_up>,
-						<1 RK_PB0 1 &pcfg_pull_none>;
+				rockchip,pins = <1 RK_PB1 1 &pcfg_pull_none>,
+						<1 RK_PB0 1 &pcfg_pull_up>;
 			};
 
 			uart0_cts: uart0-cts {
@@ -1284,8 +1284,8 @@ uart0_rts_pin: uart0-rts-pin {
 
 		uart1 {
 			uart1_xfer: uart1-xfer {
-				rockchip,pins = <3 RK_PA4 4 &pcfg_pull_up>,
-						<3 RK_PA6 4 &pcfg_pull_none>;
+				rockchip,pins = <3 RK_PA4 4 &pcfg_pull_none>,
+						<3 RK_PA6 4 &pcfg_pull_up>;
 			};
 
 			uart1_cts: uart1-cts {
@@ -1303,15 +1303,15 @@ uart1_rts_pin: uart1-rts-pin {
 
 		uart2-0 {
 			uart2m0_xfer: uart2m0-xfer {
-				rockchip,pins = <1 RK_PA0 2 &pcfg_pull_up>,
-						<1 RK_PA1 2 &pcfg_pull_none>;
+				rockchip,pins = <1 RK_PA0 2 &pcfg_pull_none>,
+						<1 RK_PA1 2 &pcfg_pull_up>;
 			};
 		};
 
 		uart2-1 {
 			uart2m1_xfer: uart2m1-xfer {
-				rockchip,pins = <2 RK_PA0 1 &pcfg_pull_up>,
-						<2 RK_PA1 1 &pcfg_pull_none>;
+				rockchip,pins = <2 RK_PA0 1 &pcfg_pull_none>,
+						<2 RK_PA1 1 &pcfg_pull_up>;
 			};
 		};
 
-- 
2.29.2

Re: [PATCH] arm64: dts: rockchip: rk3328: Fix UART pull-ups

[Heiko Stuebner]

On Fri, 4 Dec 2020 14:48:05 +0800, Chen-Yu Tsai wrote:
> For UARTs, the local pull-ups should be on the RX pin, not the TX pin.
> UARTs transmit active-low, so a disconnected RX pin should be pulled
> high instead of left floating to prevent noise being interpreted as
> transmissions.
> 
> This gets rid of bogus sysrq events when the UART console is not
> connected.

Applied, thanks!

[1/1] arm64: dts: rockchip: rk3328: Fix UART pull-ups
      commit: 94dad6bed3c86c00050bf7c2b2ad6b630facae31

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