Noting the approaching 2.6.24 merge window which will follow the upcoming release of the 2.6.23 kernel, MultiMedia Card (MMC) subsystem maintainer Pierre Ossman described what he plans to push upstream, "this release will probably be one of the biggest ones for the MMC layer so far. The major pieces are SDIO and SPI support, but there are several small nuggets as well." Regarding the new Secure Digital Input Output (SDIO) stack he noted, "gone are the days of having to rely on proprietary stacks for SDIO support in Linux. So no more spotty support for hosts and possible GPL problems. SDIO will now be a standard feature of Linux." He also described three working drivers already ported to the new stack.
Pierre went on to discuss the Serial Peripheral Interface (SPI) stack, "the second large feature is the fact that you can now use your SPI controllers for MMC, SD and SDIO. Yes, even SDIO works nicely over SPI. This means that a lot more systems can get storage and expansion I/O at basically the cost of a connector." He added, "David Brownell is currently marked as providing 'odd fixes' for the mmc_spi driver, but we could really use a proper maintainer. So if you have sufficient experience with Linux' SPI interface and the time, please raise your hand."