rk3328_iomux_set_drive_strength
rk3328_iomux_set_drive_strength(sc, bank, idx, GRF_GPIO_E_CTL_2MA);
rk3328_iomux_set_drive_strength(sc, bank, idx, GRF_GPIO_E_CTL_4MA);
rk3328_iomux_set_drive_strength(sc, bank, idx, GRF_GPIO_E_CTL_8MA);
rk3328_iomux_set_drive_strength(sc, bank, idx, GRF_GPIO_E_CTL_12MA);