STMicroelectronics ST33ZP24 TPM 1.2 security chip
A Trusted Platform Module 1.2 security chip from STMicroelectronics, attached over I2C or SPI, used in embedded and industrial systems from the mid-2010s onward to store cryptographic keys, measure boot integrity, and provide hardware-backed attestation. ST has since moved new designs to its ST33TPHF2 and ST33KTPM families, leaving ST33ZP24 as a legacy part still found in older fielded hardware.
recommendation
Worth keeping but documenting its niche: although ST no longer markets the ST33ZP24 for new designs and steers customers toward newer TPM parts, the driver is still being actively maintained, with a real bug fix landing in 2026 and getting backported to stable trees. That maintenance signal, plus the chip's likely continued presence in long-lived embedded and industrial deployments, makes removal premature, but a note flagging it as legacy silicon would help future cleanup decisions.
repository signals
sources
- lore.kernel.org
The driver received a real bug fix in 2026 ('Fix missing cleanup on get_burstcount() error') and that fix was backported to stable trees, indicating ongoing maintenance rather than abandonment.
- lore.kernel.org
The directory still sees upstream churn in 2024, though at least some of it is treewide API cleanup rather than feature work.
- st.com
ST still sells newer TPM parts for the same market/use case, but the marketed current part is ST33TPHF2EI2C, not the older ST33ZP24 named by this driver.
- st.com
ST's current TPM marketing points customers to the newer ST33KTPM line for new designs, suggesting the Linux driver target is legacy silicon rather than a current flagship deployment choice.
- cateee.net
LKDDb shows this exact driver family remains present in current kernel series, so it is not already removed upstream.
codex reasoning notes (technical)
Local shell grep identified this as an STMicroelectronics TPM 1.2 I2C/SPI driver for ST33ZP24. lore_activity on st33zp24.c/i2c.c showed recent real maintenance and stable backports in 2026, which argues against deprecate/remove. Attempts to use lore_regex for explicit removal-thread detection timed out; no removal evidence was obtained. Web search found current ST product pages for newer ST33 TPM families (ST33TPHF2, ST33KTPM), but not a current ST33ZP24 sales page, so I infer the exact hardware is legacy while deployments likely persist in older embedded/industrial systems. Replacement is null because migration is to newer TPM hardware/standards, not a drop-in upstream driver.