I designed a board with OMAP3530 where MicroSD works through a voltage translator TXS0108.
MMC1_VDDS & MMC1a_VDDS are powered by a fixed 1.8V source
TXS0108 is powered by 1.8V on the CPU side and 3.3V at MicroSD side
The problem appear during Linux boot. It either boots or not. If it boots then sometimes a lot of SD I/O errors appear and it remounts to RO mode. Investigating this issue I found that there is PBIASLITEVMODE0 bit in the CONTROL_PBIAS_LITE register which is always set to 1 (MMC1 is in 3V operation). May be the problem is there? Can anybody tell the place in the kernel where the VMMC1 value is set? I use 2.6.32 but it did not change dramatically in 3.0x. I just can’t find where to set this voltage to 1.8V operation mode.