The charger built into the PMIC cannot automatically provide information to the LEDs. To do so your main application running on the MAX32620 has to handle the PMIC interrupt on the IRQ pin (C2), and after sorting out what causes the interrupt, the application has to set the LEDs accordingly. Example firmware for Arduino can be found here: https://github.com/amperpirat/MAX32620FTHR-Arduino/tree/master/MAX32620FTHR_PMIC_Charge-LED/MAX32620FTHR_PMIC_Charge-LED