STMicroelectronics ST21NFCA Near-Field Communication controllers
An STMicroelectronics near-field communication (NFC) chip family connected over I2C, used to add contactless features such as tap-to-pair, transit cards, and mobile payments to embedded devices and smartphones from the early-to-mid 2010s.
recommendation
Worth keeping but documenting its niche: the specific ST21NFCA part appears to be older silicon with limited current deployment, and there is no sign it is still sold new in 2025. However, the code is still receiving routine upstream maintenance, no replacement covers the same hardware, and ST's broader ST21 NFC family (ST21NFCD, ST21NFCJ) remains in active production, so removing it would orphan existing devices for no real gain.
repository signals
sources
- lore.kernel.org
The driver directory was still being touched upstream in 2025; the visible recent lore hit is a treewide timers cleanup, not a removal/deprecation series.
- st.com
STMicroelectronics still had later ST21 NFC controller family devices marked active and in volume production in 2025, showing the broader product family/use-case remains current even if the exact ST21NFCA part appears older.
- st.com
Another later ST21 NFC controller family product was active in 2025, reinforcing that the family is not obsolete as a whole.
codex reasoning notes (technical)
Local exec_command on Kconfig identifies this as the STMicroelectronics ST21NFCA core plus I2C NFC driver. lore_file_timeline on drivers/nfc/st21nfca/core.c showed activity through 2025 and no evident removal traffic; recent hits are mostly treewide maintenance. web search returned official ST product pages for later ST21 NFC controllers (ST21NFCD/ST21NFCJ) as active in 2025, but I found no direct evidence that the exact ST21NFCA SKU is still sold new. That supports low ongoing deployments and legacy status for this exact driver, but not removal: upstream still carries it, there is no natural in-tree replacement for the same silicon, and the family/use-case is still relevant.