| RTSX(4) | Device Drivers Manual | RTSX(4) | 
rtsx —
rtsx* at pci?
sdmmc* at rtsx?
rtsx driver provides support for the Realtek
  RTS5209, RTS5227, RTS5229, RTS522A, RTS525A, RTL8402, RTL8411 and RTL8411B SD
  card readers.
The sdmmc(4) subsystem performs SD/MMC transactions to communicate with whatever MMC, SD or SDHC devices are inserted into the SD slot.
rtsx driver first appeared in
  OpenBSD 5.3 and in NetBSD 7.0.
rtsx driver was written by Stefan
  Sperling ⟨stsp@openbsd.org⟩ for
  OpenBSD and ported to NetBSD
  by NONAKA Kimihiro ⟨nonaka@netbsd.org⟩.
rtsx driver does not support MS (Memory Stick) and
  xD (Extreme Digital) devices even though the hardware supports them.
Support for SDIO interrupts is not implemented.
| April 27, 2020 | NetBSD 10.0 |