drivers: gpio: gpio_mcux_igpio: add pull strength configuration

The i.MXRT10xx series have configurable GPIO pull strengths.

These are available for configuration in the pinctrl system, but not for
regular GPIO use.

This commit adds SOC-series specific GPIO configuration bits for selecting
weak or strong GPIO pulls, similar to drive strengths available from other
GPIO pin configuration examples.

This has been tested on a custom i.MXRT1062 product.

Signed-off-by: Stefan Giroux <[email protected]>

Author: sgfeniex

drivers/gpio/gpio_mcux_igpio.c

@@ -17,6 +17,7 @@
 #include <fsl_gpio.h>
 
 #include <zephyr/drivers/pinctrl.h>
+#include <zephyr/dt-bindings/gpio/nxp-imx-igpio.h>
 
 #include <zephyr/drivers/gpio/gpio_utils.h>
 
@@ -90,8 +91,13 @@ static int mcux_igpio_configure(const struct device *dev,
 	if (((flags & GPIO_PULL_UP) != 0) || ((flags & GPIO_PULL_DOWN) != 0)) {
 		reg |= IOMUXC_SW_PAD_CTL_PAD_PUE_MASK;
 		if (((flags & GPIO_PULL_UP) != 0)) {
-			/* Use 100K pullup */
-			reg |= IOMUXC_SW_PAD_CTL_PAD_PUS(2);
+			if ((flags & NXP_IGPIO_PULL_STRONG) != 0) {
+				/* Use 22K pullup */
+				reg |= IOMUXC_SW_PAD_CTL_PAD_PUS(3);
+			} else {
+				/* Use 100K pullup */
+				reg |= IOMUXC_SW_PAD_CTL_PAD_PUS(2);
+			}
 		} else {
 			/* 100K pulldown */
 			reg &= ~IOMUXC_SW_PAD_CTL_PAD_PUS_MASK;

include/zephyr/dt-bindings/gpio/nxp-imx-igpio.h

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2025 Feniex Industries Inc.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#ifndef ZEPHYR_INCLUDE_DT_BINDINGS_GPIO_NXP_IMX_IGPIO_H_
+#define ZEPHYR_INCLUDE_DT_BINDINGS_GPIO_NXP_IMX_IGPIO_H_
+
+/**
+ * @name GPIO pull strength flags
+ *
+ * The pull strength flags are a Zephyr specific extension of the standard GPIO
+ * flags specified by the Linux GPIO binding. Only applicable for NXP IMX
+ * SoCs.
+ *
+ * The interface supports two different pull strengths:
+ * `WEAK` - The lowest pull strength supported by the HW
+ * `STRONG` - The highest pull strength supported by the HW
+ *
+ * @{
+ */
+/** @cond INTERNAL_HIDDEN */
+#define NXP_IGPIO_PULL_STRENGTH_POS 8
+#define NXP_IGPIO_PULL_STRENGTH_MASK (0x1U << NXP_IGPIO_PULL_STRENGTH_POS)
+/** @endcond */
+
+/** pull up/down strengths (only applies to CONFIG_SOC_SERIES_IMXRT10XX) */
+#define NXP_IGPIO_PULL_WEAK (0x0U << NXP_IGPIO_PULL_STRENGTH_POS)
+#define NXP_IGPIO_PULL_STRONG (0x1U << NXP_IGPIO_PULL_STRENGTH_POS)
+
+/** @} */
+
+#endif /* ZEPHYR_INCLUDE_DT_BINDINGS_GPIO_NXP_IMX_IGPIO_H_ */