doc/services/nvmem/usage_example.txt

#include <zephyr/nvmem.h>

static const struct nvmem_cell mac_address =
	NVMEM_CELL_GET_BY_NAME(DT_NODELABEL(my_consumer), mac_address);

int main(void)
{
	uint8_t mac[6];
	int ret;

	if (!nvmem_cell_is_ready(&mac_address)) {
		printk("NVMEM cell is not ready\n");
		return -ENODEV;
	}

	ret = nvmem_cell_read(&mac_address, mac, 0, sizeof(mac));
	if (ret < 0) {
		printk("Failed to read MAC address: %d\n", ret);
		return ret;
	}

	/* ... */
}