Analog Devices AD2S Resolver-to-Digital Converters
A small family of SPI-attached resolver-to-digital converter chips from Analog Devices that translate the analog sine/cosine outputs of a rotary resolver into a digital angle and velocity reading. They are used in industrial motor control, robotics, and automotive applications where rugged absolute position sensing is needed instead of optical encoders.
recommendation
It should stay in the kernel because the AD2S90, AD2S1200, AD2S1205, and AD2S1210 are still sold new by Analog Devices in 2025, and the code is actively maintained upstream — AD2S1210 support was added as recently as 2023 and reviewed patches continued through 2025 and into 2026. No replacement covers these specific chips, so removing the directory would orphan working industrial and automotive hardware.
repository signals
sources
- lore.kernel.org
The directory still sees upstream attention in 2026; ad2s1210 received a resolver-specific patch on 2026-03-16.
- lore.kernel.org
The driver had reviewed and acked maintenance work in 2025, indicating active subsystem stewardship rather than abandonment.
- lore.kernel.org
AD2S1210 support was added upstream in 2023, so part of this directory is relatively new rather than legacy-only code.
- analog.com
Analog Devices lists AD2S1210 as PRODUCTION and offers Sample & Buy, supporting that hardware was still sold new in 2025.
- analog.com
Analog Devices lists AD2S1205 as PRODUCTION with ordering information, showing ongoing new-hardware availability for this family.
- analog.com
Analog Devices lists AD2S90 as PRODUCTION with priced orderable models, indicating even the oldest supported chip remains commercially available.
codex reasoning notes (technical)
Local `rg`/`sed` on Kconfig and MODULE_DESCRIPTION identified this as real IIO SPI driver code for AD2S90/1200/1205/1210 resolver converters. `lore_file_timeline` and `lore_activity` provided the cited lore URLs and show steady 2023-2026 maintenance, including reviewed 2025 patches; sampled lore evidence did not show a removal/deprecation thread, so absence of removal talk is an inference from recent activity rather than exhaustive proof. `web.search_query` found the official Analog Devices product pages, all marked PRODUCTION with ordering/sample paths, so the hardware family still appears to be sold for industrial/automotive niches. No upstream replacement driver covers the same chips; these are chip-specific drivers, so removal/deprecation is not justified.