We want to support UHS-I mode on our board for our sd-card (sd3 port of imx). Hardware wise, we kind of copied the sabre sd automative schematics,but we didn't wired the sd3 RST signal to a power regulator to switch off and on the sd-card power (that is, the power of the sd-card is always switched on).
In the imx6qdl-sabreauto.dtsi, at the usdhc3 declaration there is a paragraph stating that power off is needed for SD3.0 card re-enumeration in UHS mode.
Hence, my question is, is it absolutely mandatory to have a vmmc-regulator with power off / on declared on SD3_RST pin declared to support UHS mode at run time ? (not at boot).
Thank you guys,
ps : I'm using a 3.10.17 freescale linux kernel.