I am working on NXP MPC5748G development board and interface SDIO with Marvell 88w8987 adapter board.
SDIO on 3.3V bring up successfully but SDIO on 1.8V is not bring up and initial command to get voltage response is not getting as expected.
So please let me know if any other information is needed for this issue.
I don't think there's HW support for switch from 3.3V to 1.8V voltage levels. All the IOs used for the interface are supplied by VDD_HV_A domain which can be only 3.3V - 5V. The IO pads are standard ones, there's no this in-built feature.
For example, I saw on some i.MX microcontroller that there's separate domain for these IO pads and VSELECT signal is used for external circuit to switch the supply voltage for this domain. But there's no such option on MPC5748G.