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arm64: dts: rockchip: rk3328: Fix UART pull-ups

PATCH Applied Chen-Yu Tsai 2 participants 2 messages Dec 4, 2020

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Chen-Yu Tsai

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PATCH 1/1 arm64: dts: rockchip: rk3328: Fix UART pull-ups

From: Chen-Yu Tsai <[email protected]>

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 <[email protected]>
---
 arch/arm64/boot/dts/rockchip/rk3328.dtsi | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)
arch/arm64/boot/dts/rockchip/rk3328.dtsi +8 -8
index 521c4678ec35..1e3aa6acbc11 100644
@@ -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>;
 			};
 		};
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2.29.2


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maintainer Applied
#1 lore raw
Quoted 7 lines · Chen-Yu Tsai

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,

Signature · 6 lines
Heiko Stuebner <[email protected]>

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