linux-drivers/
drivers/pwm

PWM (Pulse-Width Modulation) controller subsystem

Generic framework and per-vendor drivers for the pulse-width modulation hardware blocks built into modern SoCs and discrete chips. PWM outputs are everywhere in current systems: dimming LCD backlights and LEDs, controlling fan speed, driving piezo buzzers, and feeding voltage regulators on boards from Raspberry Pi to Apple Silicon laptops.

keep conf=0.96 deploy=high replacement=none subsystem=pwm category=infrastructure
96%

recommendation

It should stay because this is a live, widely used subsystem under active development, with new feature work and stable-tree backports landing as recently as 2026. New hardware continues to ship with PWM blocks that depend on it (the Raspberry Pi 5's fan header is one visible example), and the directory contains drivers for current SoCs from Apple, Broadcom, Airoha and many others, with no single replacement on the horizon.

repository signals

82 files
28,671 source lines
826 commits, 5y
+17,104 / −9,470 lines added / removed, 5y
124 authors, 5y
monthly commits · 2021-04-21 → 2026-04-21 · 826 total · active in 59/61 months
2021 2022 2023 2024 2025 2026 2021-04: 16 commits · +505 −270 2021-05: 21 commits · +358 −283 2021-06: 15 commits · +160 −244 2021-07: 57 commits · +244 −500 2021-08: 4 commits · +128 −107 2021-09: 5 commits · +35 −23 2021-10: 3 commits · +107 −26 2021-11: 19 commits · +385 −250 2021-12: 3 commits · +59 −34 2022-01: 4 commits · +14 −22 2022-02: 8 commits · +65 −72 2022-03: 4 commits · +628 −18 2022-04: 14 commits · +316 −220 2022-05: 11 commits · +243 −120 2022-06: 1 commit · +4 −24 2022-07: 11 commits · +292 −91 2022-08: 6 commits · +19 −58 2022-09: 8 commits · +74 −76 2022-10: 5 commits · +23 −16 2022-11: 7 commits · +20 −32 2022-12: 37 commits · +280 −219 2023-01: 2 commits · +103 −9 2023-02: 1 commit · +2 −2 2023-03: 39 commits · +84 −123 2023-04: 10 commits · +236 −105 2023-05: 13 commits · +662 −127 2023-06: 1 commit · +563 −0 2023-07: 39 commits · +295 −437 2023-08: 5 commits · +40 −97 2023-09: 15 commits · +415 −506 2023-10: 23 commits · +128 −110 2023-11: 9 commits · +50 −65 2023-12: 11 commits · +137 −102 2024-01: 13 commits · +445 −490 2024-02: 159 commits · +1,637 −1,521 2024-03: 20 commits · +810 −871 2024-04: 4 commits · +71 −42 2024-05: 1 commit · +2 −2 2024-06: 22 commits · +703 −214 2024-07: 12 commits · +274 −81 2024-08: 6 commits · +11 −8 2024-09: 14 commits · +1,291 −530 2024-10: 7 commits · +146 −26 2024-11: 6 commits · +108 −30 2024-12: 7 commits · +25 −28 2025-01: 6 commits · +51 −14 2025-02: 8 commits · +707 −17 2025-03: 2 commits · +311 −10 2025-04: 24 commits · +1,072 −133 2025-05: 9 commits · +243 −92 2025-06: 12 commits · +183 −168 2025-07: 28 commits · +722 −524 2025-08: 9 commits · +321 −104 2025-09: 3 commits · +4 −5 2025-10: 10 commits · +1,229 −117 2025-11: 5 commits · +40 −36 2025-12: 3 commits · +4 −3 2026-01: 6 commits · +16 −12 2026-02: 3 commits · +4 −4 2026-03: 0 commits · +0 −0 2026-04: 0 commits · +0 −0

sources

  1. lore.kernel.org

    Recent upstream PWM core work was still landing in 2026, indicating active maintenance rather than deprecation.

  2. lore.kernel.org

    PWM fixes were being backported to stable in 2026, which is strong evidence of ongoing supported deployments.

  3. docs.kernel.org

    Kernel documentation describes PWM as a generic framework for SoC/discrete PWM blocks used for LEDs, fans, backlights, regulators, and other current system functions.

  4. raspberrypi.com

    Raspberry Pi 5 documentation shows a current-production board exposing a dedicated PWM fan connector, demonstrating new-hardware deployment in 2025-era products.

codex reasoning notes (technical)

Obtained lore URLs via `mcp__lore_http__.lore_file_timeline` on `drivers/pwm/core.c`; it showed heavy activity from 2021-2026 with recent fixes/features/backports and no removal trend in the sampled history. Obtained docs.kernel.org and Raspberry Pi URLs via `web.search_query`. Local `drivers/pwm/Kconfig` inspection via shell showed many current SoC/vendor drivers (Apple, Airoha, Broadcom/Raspberry Pi, etc.). This directory is an active subsystem for widely deployed modern PWM controller hardware, not a legacy orphan; there is no single replacement driver for the same use case.