diff --git a/drivers/st/regulator/regulator_core.c b/drivers/st/regulator/regulator_core.c
new file mode 100644
index 0000000..94b3cef
--- /dev/null
+++ b/drivers/st/regulator/regulator_core.c
@@ -0,0 +1,536 @@
+/*
+ * Copyright (c) 2021, STMicroelectronics - All Rights Reserved
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdint.h>
+#include <string.h>
+
+#include <common/debug.h>
+#include <drivers/delay_timer.h>
+#include <drivers/st/regulator.h>
+#include <libfdt.h>
+
+#define MAX_PROPERTY_LEN 64
+
+static struct rdev rdev_array[PLAT_NB_RDEVS];
+
+#define for_each_rdev(rdev) \
+	for (rdev = rdev_array; rdev < (rdev_array + PLAT_NB_RDEVS); rdev++)
+
+#define for_each_registered_rdev(rdev) \
+	for (rdev = rdev_array; \
+	     (rdev < (rdev_array + PLAT_NB_RDEVS)) && (rdev->desc != NULL); rdev++)
+
+static void lock_driver(const struct rdev *rdev)
+{
+	if (rdev->desc->ops->lock != NULL) {
+		rdev->desc->ops->lock(rdev->desc);
+	}
+}
+
+static void unlock_driver(const struct rdev *rdev)
+{
+	if (rdev->desc->ops->unlock != NULL) {
+		rdev->desc->ops->unlock(rdev->desc);
+	}
+}
+
+static struct rdev *regulator_get_by_phandle(int32_t phandle)
+{
+	struct rdev *rdev;
+
+	for_each_registered_rdev(rdev) {
+		if (rdev->phandle == phandle) {
+			return rdev;
+		}
+	}
+
+	WARN("%s: phandle %d not found\n", __func__, phandle);
+	return NULL;
+}
+
+/*
+ * Get a regulator from its node name
+ *
+ * @fdt - pointer to device tree memory
+ * @node_name - name of the node "ldo1"
+ * Return pointer to rdev if succeed, NULL else.
+ */
+struct rdev *regulator_get_by_name(const char *node_name)
+{
+	struct rdev *rdev;
+
+	assert(node_name != NULL);
+	VERBOSE("get %s\n", node_name);
+
+	for_each_registered_rdev(rdev) {
+		if (strcmp(rdev->desc->node_name, node_name) == 0) {
+			return rdev;
+		}
+	}
+
+	WARN("%s: %s not found\n", __func__, node_name);
+	return NULL;
+}
+
+static int32_t get_supply_phandle(const void *fdt, int node, const char *name)
+{
+	const fdt32_t *cuint;
+	int len __unused;
+	int supply_phandle = -FDT_ERR_NOTFOUND;
+	char prop_name[MAX_PROPERTY_LEN];
+
+	len = snprintf(prop_name, MAX_PROPERTY_LEN - 1, "%s-supply", name);
+	assert((len >= 0) && (len < MAX_PROPERTY_LEN - 1));
+
+	cuint = fdt_getprop(fdt, node, prop_name, NULL);
+	if (cuint != NULL) {
+		supply_phandle = fdt32_to_cpu(*cuint);
+		VERBOSE("%s: supplied by %d\n", name, supply_phandle);
+	}
+
+	return supply_phandle;
+}
+
+/*
+ * Get a regulator from a supply name
+ *
+ * @fdt - pointer to device tree memory
+ * @node - offset of the node that contains the supply description
+ * @name - name of the supply "vdd" for "vdd-supply'
+ * Return pointer to rdev if succeed, NULL else.
+ */
+struct rdev *regulator_get_by_supply_name(const void *fdt, int node, const char *name)
+{
+	const int p = get_supply_phandle(fdt, node, name);
+
+	if (p < 0) {
+		return NULL;
+	}
+
+	return regulator_get_by_phandle(p);
+}
+
+static int __regulator_set_state(struct rdev *rdev, bool state)
+{
+	if (rdev->desc->ops->set_state == NULL) {
+		return -ENODEV;
+	}
+
+	return rdev->desc->ops->set_state(rdev->desc, state);
+}
+
+/*
+ * Enable regulator
+ *
+ * @rdev - pointer to rdev struct
+ * Return 0 if succeed, non 0 else.
+ */
+int regulator_enable(struct rdev *rdev)
+{
+	int ret;
+
+	assert(rdev != NULL);
+
+	ret = __regulator_set_state(rdev, STATE_ENABLE);
+
+	udelay(rdev->enable_ramp_delay);
+
+	return ret;
+}
+
+/*
+ * Disable regulator
+ *
+ * @rdev - pointer to rdev struct
+ * Return 0 if succeed, non 0 else.
+ */
+int regulator_disable(struct rdev *rdev)
+{
+	int ret;
+
+	assert(rdev != NULL);
+
+	ret = __regulator_set_state(rdev, STATE_DISABLE);
+
+	udelay(rdev->enable_ramp_delay);
+
+	return ret;
+}
+
+/*
+ * Regulator enabled query
+ *
+ * @rdev - pointer to rdev struct
+ * Return 0 if disabled, 1 if enabled, <0 else.
+ */
+int regulator_is_enabled(const struct rdev *rdev)
+{
+	int ret;
+
+	assert(rdev != NULL);
+
+	VERBOSE("%s: is en\n", rdev->desc->node_name);
+
+	if (rdev->desc->ops->get_state == NULL) {
+		return -ENODEV;
+	}
+
+	lock_driver(rdev);
+
+	ret = rdev->desc->ops->get_state(rdev->desc);
+	if (ret < 0) {
+		ERROR("regul %s get state failed: err:%d\n",
+		      rdev->desc->node_name, ret);
+	}
+
+	unlock_driver(rdev);
+
+	return ret;
+}
+
+/*
+ * Set regulator voltage
+ *
+ * @rdev - pointer to rdev struct
+ * @mvolt - Target voltage level in millivolt
+ * Return 0 if succeed, non 0 else.
+ */
+int regulator_set_voltage(struct rdev *rdev, uint16_t mvolt)
+{
+	int ret;
+
+	assert(rdev != NULL);
+
+	VERBOSE("%s: set mvolt\n", rdev->desc->node_name);
+
+	if (rdev->desc->ops->set_voltage == NULL) {
+		return -ENODEV;
+	}
+
+	if ((mvolt < rdev->min_mv) || (mvolt > rdev->max_mv)) {
+		return -EPERM;
+	}
+
+	lock_driver(rdev);
+
+	ret = rdev->desc->ops->set_voltage(rdev->desc, mvolt);
+	if (ret < 0) {
+		ERROR("regul %s set volt failed: err:%d\n",
+		      rdev->desc->node_name, ret);
+	}
+
+	unlock_driver(rdev);
+
+	return ret;
+}
+
+/*
+ * Set regulator min voltage
+ *
+ * @rdev - pointer to rdev struct
+ * Return 0 if succeed, non 0 else.
+ */
+int regulator_set_min_voltage(struct rdev *rdev)
+{
+	return regulator_set_voltage(rdev, rdev->min_mv);
+}
+
+/*
+ * Get regulator voltage
+ *
+ * @rdev - pointer to rdev struct
+ * Return milli volts if succeed, <0 else.
+ */
+int regulator_get_voltage(const struct rdev *rdev)
+{
+	int ret;
+
+	assert(rdev != NULL);
+
+	VERBOSE("%s: get volt\n", rdev->desc->node_name);
+
+	if (rdev->desc->ops->get_voltage == NULL) {
+		return rdev->min_mv;
+	}
+
+	lock_driver(rdev);
+
+	ret = rdev->desc->ops->get_voltage(rdev->desc);
+	if (ret < 0) {
+		ERROR("regul %s get voltage failed: err:%d\n",
+		      rdev->desc->node_name, ret);
+	}
+
+	unlock_driver(rdev);
+
+	return ret;
+}
+
+/*
+ * List regulator voltages
+ *
+ * @rdev - pointer to rdev struct
+ * @levels - out: array of supported millitvolt levels from min to max value
+ * @count - out: number of possible millivolt values
+ * Return 0 if succeed, non 0 else.
+ */
+int regulator_list_voltages(const struct rdev *rdev, const uint16_t **levels, size_t *count)
+{
+	int ret;
+	size_t n;
+
+	assert(rdev != NULL);
+	assert(levels != NULL);
+	assert(count != NULL);
+
+	VERBOSE("%s: list volt\n", rdev->desc->node_name);
+
+	if (rdev->desc->ops->list_voltages == NULL) {
+		return -ENODEV;
+	}
+
+	lock_driver(rdev);
+
+	ret = rdev->desc->ops->list_voltages(rdev->desc, levels, count);
+
+	unlock_driver(rdev);
+
+	if (ret < 0) {
+		ERROR("regul %s list_voltages failed: err: %d\n",
+		      rdev->desc->node_name, ret);
+		return ret;
+	}
+
+	/*
+	 * Reduce the possible values depending on min and max from device-tree
+	 */
+	n = *count;
+	while ((n > 1U) && ((*levels)[n - 1U] > rdev->max_mv)) {
+		n--;
+	}
+
+	/* Verify that max val is a valid value */
+	if (rdev->max_mv != (*levels)[n - 1]) {
+		ERROR("regul %s: max value %u is invalid\n",
+		      rdev->desc->node_name, rdev->max_mv);
+		return -EINVAL;
+	}
+
+	while ((n > 1U) && ((*levels[0U]) < rdev->min_mv)) {
+		(*levels)++;
+		n--;
+	}
+
+	/* Verify that min is not too high */
+	if (n == 0U) {
+		ERROR("regul %s set min voltage is too high\n",
+		      rdev->desc->node_name);
+		return -EINVAL;
+	}
+
+	/* Verify that min val is a valid vlue */
+	if (rdev->min_mv != (*levels)[0U]) {
+		ERROR("regul %s: min value %u is invalid\n",
+		      rdev->desc->node_name, rdev->min_mv);
+		return -EINVAL;
+	}
+
+	*count = n;
+
+	VERBOSE("rdev->min_mv=%u rdev->max_mv=%u\n", rdev->min_mv, rdev->max_mv);
+
+	return 0;
+}
+
+/*
+ * Get regulator voltages range
+ *
+ * @rdev - pointer to rdev struct
+ * @min_mv - out: min possible millivolt value
+ * @max_mv - out: max possible millivolt value
+ * Return 0 if succeed, non 0 else.
+ */
+void regulator_get_range(const struct rdev *rdev, uint16_t *min_mv, uint16_t *max_mv)
+{
+	assert(rdev != NULL);
+
+	if (min_mv != NULL) {
+		*min_mv = rdev->min_mv;
+	}
+	if (max_mv != NULL) {
+		*max_mv = rdev->max_mv;
+	}
+}
+
+/*
+ * Set regulator flag
+ *
+ * @rdev - pointer to rdev struct
+ * @flag - flag value to set (eg: REGUL_OCP)
+ * Return 0 if succeed, non 0 else.
+ */
+int regulator_set_flag(struct rdev *rdev, uint16_t flag)
+{
+	int ret;
+
+	/* check that only one bit is set on flag */
+	if (__builtin_popcount(flag) != 1) {
+		return -EINVAL;
+	}
+
+	/* REGUL_ALWAYS_ON and REGUL_BOOT_ON are internal properties of the core */
+	if ((flag == REGUL_ALWAYS_ON) || (flag == REGUL_BOOT_ON)) {
+		rdev->flags |= flag;
+		return 0;
+	}
+
+	if (rdev->desc->ops->set_flag == NULL) {
+		ERROR("%s can not set any flag\n", rdev->desc->node_name);
+		return -ENODEV;
+	}
+
+	lock_driver(rdev);
+
+	ret = rdev->desc->ops->set_flag(rdev->desc, flag);
+
+	unlock_driver(rdev);
+
+	if (ret != 0) {
+		ERROR("%s: could not set flag %d ret=%d\n",
+		      rdev->desc->node_name, flag, ret);
+		return ret;
+	}
+
+	rdev->flags |= flag;
+
+	return 0;
+}
+
+/*
+ * Parse the device-tree for a regulator
+ *
+ * Read min/max voltage from dt and check its validity
+ * Read the properties, and call the driver to set flags
+ * Read power supply phandle
+ * Read and store low power mode states
+ *
+ * @rdev - pointer to rdev struct
+ * @node - device-tree node offset of the regulator
+ * Return 0 if disabled, 1 if enabled, <0 else.
+ */
+static int parse_dt(struct rdev *rdev, int node)
+{
+	void *fdt;
+	const fdt32_t *cuint;
+	const uint16_t *levels;
+	size_t size;
+	int ret;
+
+	VERBOSE("%s: parse dt\n", rdev->desc->node_name);
+
+	if (fdt_get_address(&fdt) == 0) {
+		return -ENOENT;
+	}
+
+	rdev->phandle = fdt_get_phandle(fdt, node);
+
+	cuint = fdt_getprop(fdt, node, "regulator-min-microvolt", NULL);
+	if (cuint != NULL) {
+		uint16_t min_mv;
+
+		min_mv = (uint16_t)(fdt32_to_cpu(*cuint) / 1000U);
+		VERBOSE("%s: min_mv=%d\n", rdev->desc->node_name, (int)min_mv);
+		if (min_mv <= rdev->max_mv) {
+			rdev->min_mv = min_mv;
+		} else {
+			ERROR("%s: min_mv=%d is too high\n",
+			      rdev->desc->node_name, (int)min_mv);
+			return -EINVAL;
+		}
+	}
+
+	cuint = fdt_getprop(fdt, node, "regulator-max-microvolt", NULL);
+	if (cuint != NULL) {
+		uint16_t max_mv;
+
+		max_mv = (uint16_t)(fdt32_to_cpu(*cuint) / 1000U);
+		VERBOSE("%s: max_mv=%d\n", rdev->desc->node_name, (int)max_mv);
+		if (max_mv >= rdev->min_mv) {
+			rdev->max_mv = max_mv;
+		} else {
+			ERROR("%s: max_mv=%d is too low\n",
+			      rdev->desc->node_name, (int)max_mv);
+			return -EINVAL;
+		}
+	}
+
+	/* validate that min and max values can be used */
+	ret = regulator_list_voltages(rdev, &levels, &size);
+	if ((ret != 0) && (ret != -ENODEV)) {
+		return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * Register a regulator driver in regulator framework.
+ * Initialize voltage range from driver description
+ *
+ * @desc - pointer to the regulator description
+ * @node - device-tree node offset of the regulator
+ * Return 0 if succeed, non 0 else.
+ */
+int regulator_register(const struct regul_description *desc, int node)
+{
+	struct rdev *rdev;
+
+	assert(desc != NULL);
+
+	VERBOSE("register %s\n", desc->node_name);
+
+	for_each_rdev(rdev) {
+		if (rdev->desc == NULL) {
+			break;
+		}
+	}
+
+	if (rdev == rdev_array + PLAT_NB_RDEVS) {
+		WARN("Not enough place for regulators, PLAT_NB_RDEVS should be increased.\n");
+		return -ENOMEM;
+	}
+
+	rdev->desc = desc;
+	rdev->enable_ramp_delay = rdev->desc->enable_ramp_delay;
+
+	if (rdev->desc->ops->list_voltages != NULL) {
+		int ret;
+		const uint16_t *levels;
+		size_t count;
+
+		lock_driver(rdev);
+
+		ret = rdev->desc->ops->list_voltages(rdev->desc, &levels, &count);
+
+		unlock_driver(rdev);
+
+		if (ret < 0) {
+			ERROR("regul %s set state failed: err:%d\n",
+			      rdev->desc->node_name, ret);
+			return ret;
+		}
+
+		rdev->min_mv = levels[0];
+		rdev->max_mv = levels[count - 1U];
+	} else {
+		rdev->max_mv = UINT16_MAX;
+	}
+
+	return parse_dt(rdev, node);
+}