CAR_PLLU_BASE_CLKENABLE_USB
tegra_reg_set_clear(bst, bsh, CAR_PLLU_BASE_REG, CAR_PLLU_BASE_CLKENABLE_USB, 0);
tegra_reg_set_clear(bst, bsh, CAR_PLLU_BASE_REG, 0, CAR_PLLU_BASE_CLKENABLE_USB);