Miscellaneous MTD Memory Devices (SPI SRAM/EERAM, DiskOnChip, RAM-backed Flash Emulators)
A grab-bag of small memory-technology drivers covering Microchip SPI SRAM and EERAM chips, M-Systems DiskOnChip G3 NAND modules, ST serial flash controllers, the DEC MS02-NV NVRAM card, and RAM-backed pseudo-devices (mtdram, phram, slram, block2mtd) that present ordinary memory as flash. Hardware spans 1990s embedded NVRAM through to small SPI memories still shipping today.
recommendation
Worth keeping but flagging as a mixed bucket. The directory is still actively maintained upstream, with a 2026 DiskOnChip G3 bugfix and a 2025 power-management cleanup to the ST SPI flash driver landing in mtd/next, and parts like the Microchip 23K256 SPI SRAM and serial EERAM line remain in production for automotive use. Several entries inside (block2mtd, mtdram, phram, slram, ms02-nv, docg3) are legacy or pseudo-device helpers with little present-day deployment, so it deserves a note that it is a low-density grab-bag rather than one coherent driver family.
repository signals
sources
- kernel.googlesource.com
The directory still receives upstream fixes in 2026; mtd/next contains a 2026 docg3 bugfix touching drivers/mtd/devices/docg3.c.
- lists.openwall.net
A 2025 patch updated drivers/mtd/devices/st_spi_fsm.c for modern PM macros, showing current maintenance rather than abandonment.
- microchip.com
Microchip lists the 23K256 SPI SRAM as 'In Production', indicating at least part of this directory still supports hardware sold new in 2025.
- microchip.com
Microchip still markets serial EERAM for automotive use, consistent with ongoing niche deployments relevant to mchp48l640-class support.
codex reasoning notes (technical)
Not a removal candidate: the directory is active upstream, with recent 2025-2026 maintenance found via web search on public kernel archives/mtd trees (kernel.googlesource mtd/next, openwall patch mirror). Directory contents are heterogeneous: some entries are clearly legacy or pseudo-device helpers (block2mtd, mtdram, phram, slram, ms02-nv, docg3), but others map to still-sold niche memory parts such as Microchip SPI SRAM/EERAM. Because current attention exists and at least some supported parts remain in production, deprecate/remove is too aggressive. Keep, but annotate as a mixed legacy/niche bucket with low present-day deployment density and no single replacement driver.