linux-drivers/
drivers/hwmon/occ

IBM POWER8/POWER9/POWER10 On-Chip Controller (OCC) hardware monitoring

Exposes sensor data (temperatures, power, voltages, frequencies) from the On-Chip Controller embedded in IBM POWER8, POWER9, and POWER10 server CPUs, reached either over I2C on POWER8 or via the Self-Boot Engine on POWER9/POWER10. It is primarily used inside OpenBMC service processors and on Linux running on IBM Power enterprise systems such as the Power E1080 and E1050.

keep conf=0.90 deploy=low replacement=none subsystem=hwmon category=other
90%

recommendation

It should stay in the kernel because IBM still sells Power10 servers like the E1080 and E1050 in 2025, and the driver is the only upstream way to read temperature, power, and frequency telemetry from the OCC on those CPUs. Maintenance is clearly active, with a stable-tagged NULL-pointer fix landing in early 2026 and ongoing OpenBMC-related work, so while deployments are confined to enterprise Power systems and their BMCs, the code is neither abandoned nor superseded.

repository signals

7 files
2,059 source lines
31 commits, 5y
+517 / −337 lines added / removed, 5y
12 authors, 5y
monthly commits · 2021-04-21 → 2026-04-21 · 31 total · active in 19/61 months
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sources

  1. lore.kernel.org

    Recent substantive upstream maintenance in March 2026: NULL-dereference fix for occ p9_sbe remove path, tagged for stable.

  2. lore.kernel.org

    The driver still receives upstream touch-ups in late 2024, indicating it is not abandoned.

  3. lore.kernel.org

    OCC driver work is tied to OpenBMC deployments, showing ongoing BMC/server use rather than a dead niche.

  4. ibm.com

    IBM was still marketing new Power10-based systems in 2025; this driver family serves IBM Power OCC monitoring on such systems.

  5. ibm.com

    IBM also marketed additional Power10 Linux-capable systems, supporting the view that relevant hardware remained on sale in 2025.

codex reasoning notes (technical)

Local code inspection via shell showed OCC hwmon support for POWER8 over I2C and POWER9/POWER10 via SBE/device-tree compatibles. lore_activity MCP on p9_sbe.c and p8_i2c.c showed real maintenance through 2026, including a stable-targeted bug fix; no removal signal surfaced in sampled lore results. Web search found current IBM Power10 product pages (E1080/E1050), so hardware is still sold new in 2025, but deployments are enterprise/BMC-specific and therefore low rather than broad. No upstream replacement driver covers the same OCC monitoring role.