thermal_coo...ice_register(9)

📦 version 7.3.1, in nixpkgs unstable

💅 thermal_coo...ice_register(9) — or, like, the Kernel API Manual entry you didn't know you needed 🎀

okay so bestie, welcome to the thermal_cooling_device_register(9) page from the Kernel API Manual. yes the title is literally abbreviated with ... in the middle, that's just how the header rolls, do not come for her 💀. let's get into it ✨

✨ NAME ✨

thermal_cooling_device_register — register a new thermal cooling device 🧊

like, you're introducing a brand new cooling device to the kernel. it's giving debutante ball. it's giving main character energy. 🌸

✨ SYNOPSIS ✨

struct thermal_cooling_device * thermal_cooling_device_register (const
char *type , void *devdata , const struct thermal_cooling_device_ops
*ops );

no cap, that's the whole signature. struct pointer out front, three args in the back. iconique. 👑

✨ ARGUMENTS ✨

  • type — the thermal cooling device type. literally just the type, bestie, that's the whole vibe check on this one 🦋
  • devdata — device private data. your personal little stash of stuff, kept private, as the name fr fr says 🙈
  • ops — standard thermal cooling devices callbacks. the standard callbacks, the classics, the moment 💅

✨ DESCRIPTION ✨

so this interface function adds a new thermal cooling device (fan/processor/...) to the /sys/class/thermal/ folder as cooling_device[0-*]. yes, that's a glob. yes, the kernel is out here just numbering them. slay 🎀

and then — this is the part — it tries to bind itself to all the thermal zone devices registered at the same time. all of them. not one, not a couple, ALL. highkey ambitious of her honestly 🔥

ngl "tries" is doing a lot of work in that sentence, so don't come crying to me if the binding is giving aspirational rather than guaranteed 💀

✨ RETURN ✨

you get back a pointer to the created struct thermal_cooling_device or an ERR_PTR. 🫶

and listen to me very carefully: the caller must check the return value with the IS_ERR*() helpers. must. not should, not maybe, MUST. this is not a drill, this is the whole safety briefing 🌈

literally do not skip the IS_ERR*() check. that's the one thing this page is yelling at you about. 😭

✨ SEE ALSO ✨

kernel file ./drivers/thermal/thermal_core.c plus the whole friend group 💜:

that's ten whole functions of further reading, bestie. iykyk 📚✨

kisses and thermal zones 🦋💖 — this page lives in ./drivers/thermal, dated October 2026, and yes she signs off the same way every time, consistency is a flex periodt 💅

📦 where this page comes from