From c1fdcd312d827bdbe6a4ca14bab8e9affc8e3140 Mon Sep 17 00:00:00 2001 From: Zhaoxiang Jin Date: Thu, 17 Jul 2025 10:53:46 +0800 Subject: [PATCH] boards/nxp: mcxn: Enable LPUART pin internal pullup resistor This commit enables MCXN236, MCXN947 LPUART pin internal pullup resistor. For MCXN947 and MCXN236, during LPUAR initialization, the RX pin is pulled down internally and STAT[RAF] is set to one. In this state, attempting to enter low power mode will trigger LPACK reset and therefore cannot truly enter low power mode. The correct setting should be to enable LPUART pin internal pullup resistor. Signed-off-by: Zhaoxiang Jin --- boards/nxp/frdm_mcxn236/frdm_mcxn236-pinctrl.dtsi | 4 +++- boards/nxp/frdm_mcxn947/frdm_mcxn947-pinctrl.dtsi | 4 +++- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/boards/nxp/frdm_mcxn236/frdm_mcxn236-pinctrl.dtsi b/boards/nxp/frdm_mcxn236/frdm_mcxn236-pinctrl.dtsi index c9256f0919f02..0f09cd23b1b48 100644 --- a/boards/nxp/frdm_mcxn236/frdm_mcxn236-pinctrl.dtsi +++ b/boards/nxp/frdm_mcxn236/frdm_mcxn236-pinctrl.dtsi @@ -1,5 +1,5 @@ /* - * Copyright 2024 NXP + * Copyright 2024-2025 NXP * SPDX-License-Identifier: Apache-2.0 */ @@ -23,6 +23,7 @@ slew-rate = "fast"; drive-strength = "low"; input-enable; + bias-pull-up; }; }; @@ -57,6 +58,7 @@ slew-rate = "fast"; drive-strength = "low"; input-enable; + bias-pull-up; }; }; diff --git a/boards/nxp/frdm_mcxn947/frdm_mcxn947-pinctrl.dtsi b/boards/nxp/frdm_mcxn947/frdm_mcxn947-pinctrl.dtsi index 40d59b9a52d04..8df1c3d4df029 100644 --- a/boards/nxp/frdm_mcxn947/frdm_mcxn947-pinctrl.dtsi +++ b/boards/nxp/frdm_mcxn947/frdm_mcxn947-pinctrl.dtsi @@ -1,5 +1,5 @@ /* - * Copyright 2024 NXP + * Copyright 2024-2025 NXP * SPDX-License-Identifier: Apache-2.0 */ @@ -61,6 +61,7 @@ slew-rate = "fast"; drive-strength = "low"; input-enable; + bias-pull-up; }; }; @@ -71,6 +72,7 @@ slew-rate = "fast"; drive-strength = "low"; input-enable; + bias-pull-up; }; };