Imagination Pistachio SoC clock controller
Programs the on-chip clock generators (PLLs, dividers, and muxes) inside Imagination Technologies' Pistachio system-on-chip, a MIPS-based IoT processor that powered the Creator Ci40 developer board launched in late 2015. Without it the CPU, peripherals, and Wi-Fi/Bluetooth radios on a Pistachio board cannot get their reference clocks set up at boot.
recommendation
Worth keeping but documenting its niche, since the Pistachio chip only ever shipped in small numbers on the 2015-era Creator Ci40 IoT development board. The code is still being maintained — a 2025 patch updated it to a newer kernel clock API and smaller cleanups landed in 2022 — and no one has proposed removing it, but real-world deployments are tiny and the boards are mostly available now as surplus new-old-stock.
repository signals
sources
- spinics.net
A substantive Pistachio clock-driver patch was still posted in 2025: 'clk: pistachio: pll: convert from round_rate() to determine_rate()'.
- lore.kernel.org
The driver received a non-treewide fix in 2022 ('clk: pistachio: Fix initconst confusion'), indicating maintained upstream build/API health.
- lore.kernel.org
The driver received an explicit Pistachio-specific cleanup in 2022 ('Declare mux table as const u32[]').
- en.wikipedia.org
Pistachio-backed Creator Ci40 hardware was introduced in November 2015 and is an older MIPS IoT development-board family rather than current mass-market hardware.
- ebay.com
As of 2026, unopened 'New' Creator Ci40 boards were still being sold by a surplus reseller, suggesting residual new-old-stock availability rather than active mainstream production.
codex reasoning notes (technical)
Real SoC clock driver directory using CLK_OF_DECLARE, not a helper library. Local shell inspection showed Pistachio DT bindings remain in-tree and arch/mips generic Marduk config still enables COMMON_CLK_PISTACHIO. Upstream activity came from local git log/tool output plus web search: a substantive 2025 clk API migration patch exists (spinics URL from web search), and earlier 2022 lore-linked fixes were visible in commit metadata from git log. I found no evidence of an active removal series. Hardware evidence from web search/open shows Pistachio's main public board (Creator Ci40) is a 2015-era dev kit; surplus sellers still list new units, so 'still sold new' is true in the narrow new-old-stock sense, but present-day deployments are likely low and niche. Result: keep the driver, but annotate as legacy/niche rather than deprecate or remove.