arm_cpuidle_read_ops(9)

📦 version 7.3.1, in nixpkgs unstable

✨ arm_cpuidle_read_ops ✨

okay bestie, welcome to the Kernel API Manual 🫶 this one's a little function with a big job: it's your lil matchmaker between a device tree cpu node and the cpuidle ops that go with it. let's get into it 💅

🌸 NAME 🌸

arm_cpuidle_read_ops — literally initialize the cpuidle ops using the device tree 🎀

🦋 SYNOPSIS 🦋

int arm_cpuidle_read_ops (struct device_node *dn , int cpu );

💖 ARGUMENTS 💖

  • dn — a pointer to a struct device node that corresponds to a cpu node. yes, that kind of node, the device-tree kind, not the node.js kind 😭
  • cpu — the cpu identifier. which cpu are we talking about? this number. periodt.

🔥 DESCRIPTION 🔥

So here's the vibe: it grabs the method name that's defined in the 'enable-method' property, retrieves the cpuidle_ops that go with it, and then does a struct copy. 💫

And why the copy, you ask? because literally all cpuidle_ops are tagged __initconst, which means they get unloaded after the init process wraps up. so if you don't copy it, you're holding a pointer to something that's about to ghost you 💀 that's the whole reason, no cap.

It returns 0 on success 🎉 and here's the fail squad:

  • -ENOENT — there's no 'enable-method' defined at all 🙈
  • -EOPNOTSUPP — no cpuidle_ops is registered for that 'enable-method', or either the init or suspend callback isn't defined 😤
bestie pls note: if either callback is missing, it's a -EOPNOTSUPP situation. both of them have to show up to the party or nobody gets in 🚪

👑 SEE ALSO 👑

Kernel file ./arch/arm/kernel/cpuidle.c, plus the whole friend group:

🌈 that's the whole page, bestie, go forth and initialize 🌈

mwah 💋 this came from the source tree at <code>./arch/arm/kernel</code>, dated October 2026, and it lives in the Kernel API Manual — see u never, love u always 🎀✨

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