omap_cm_wait_module_idle(9)

💅 omap_cm_wait_module_idle — like, the kernel-API-manual one, bestie

Okay so bestie, picture this: it's a 9-section man page, it lives in the Kernel API Manual, and its whole personality is waiting for a module to chill out. Yes, really. Let's get into it 🫶

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✨ NAME ✨

omap_cm_wait_module_idle — wait for a module to enter idle or standby

Literally what it says on the tin: you sit there, patiently, until the module stops being clocked. Main character energy for a function that just… waits. 💅

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🌸 SYNOPSIS 🌸

int omap_cm_wait_module_idle (u8 part , s16 prcm_mod , u16 idlest_reg ,
       u8 idlest_shift );

Four args, one int back. No cap, that's the whole signature. 🎀

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🦋 ARGUMENTS 🦋

• part — the PRCM partition. Which chunk of the PRCM we're talking about, that's it, that's the vibe.
• prcm_mod — the PRCM module offset. Where the module lives in the register map, lowkey the address-y bit.
• idlest_reg — the CM_IDLESTx register. The lil' status register we're gonna stare at until it tells us what we wanna hear 👀
• idlest_shift — the shift of the bit in the CM_IDLEST* register to check. Like, which specific bit in that register is the one we care about. (Note the description below says idlest_id instead of idlest_reg — that's the original's business, not mine, iykyk 🙈)

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🔥 DESCRIPTION 🔥

So what does it do? It waits for the PRCM to indicate that the module identified by (prcm_mod, idlest_id, idlest_shift) is no longer clocked. That's it. That's the whole function. Clock go bye-bye, we celebrate ✨

Returns:

• 0 — slay, success, the module went idle 🎉
• -EBUSY — the module doesn't enable in time 😭 (yes, the man page says "enable" here even though we're waiting for idle — I don't make the rules, I just report them, fr fr)
• -EINVAL — invalid, because either:
  • no per-SoC wait_module_idle function pointer has been registered 🫠, or
  • the idlest register is unknown on the SoC 💀

Heads up bestie: that -EINVAL case is the one that'll bite you if your SoC support isn't wired up. No function pointer registered = no vibes = no waiting. Periodt.

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🌈 SEE ALSO 🌈

• Kernel file ./arch/arm/mach-omap2/cm_common.c (the whole thing, iconic)
• cm_split_idlest_reg(9)
• omap_cm_wait_module_ready(9) — the other waiting function, the ready-flavored one 💜
• omap_cm_module_enable(9)
• omap_cm_module_disable(9)
• cm_register(9)
• cm_unregister(9)
• omap2_cm_base_init(9)
• omap_cm_init(9)

Go read them, they're all in the clique 🧚

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And that's the page! Big kiss to ./arch/arm/mach-omap2 for hosting this whole situation back in October 2026 — source and date both accounted for, we love a documented footer ⭐ Byeee! 🍓