devm_ioremap_resource(9)

🌸 devm_ioremap_resource(9) — Kernel API Manual 🌸

ok so bestie, let me tell you about devm_ioremap_resource(9) — it's in the Kernel API Manual and it's literally the "check it, claim it, map it" combo platter. 💅

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✨ NAME ✨

devm_ioremap_resource — check, request region, and ioremap resource

Like, all three things. In one function. She's efficient.

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✨ SYNOPSIS ✨

void __iomem * devm_ioremap_resource (struct device *dev , const struct
       resource *res );

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✨ ARGUMENTS ✨

• dev — the generic device that's handling the resource for you 🫶
• res — the resource being handled, the actual thing you're working with

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✨ DESCRIPTION ✨

okay so here's the vibe: it checks that a resource is a valid memory region, requests the memory region, and ioremaps it. That's the whole arc. 🌈

And the iconic part? All operations are managed and will be undone on driver detach. So you don't have to clean up after yourself — devm's got you. Periodt.

Usage example, literally from the source:

res = platform_get_resource(pdev, IORESOURCE_MEM, 0); base = devm_ioremap_resource(pdev->dev, res); if (IS_ERR(base)) return PTR_ERR(base);

no cap, that IS_ERR check is not optional, bestie. do not skip her. 💀

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✨ RETURN ✨

a pointer to the remapped memory, or an ERR_PTR encoded error code on failure. so check it with IS_ERR before you go doing main character things with it 👑

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✨ SEE ALSO ✨

Kernel file ./lib/devres.c — and the whole friend group:

• devm_ioremap(9)
• devm_ioremap_uc(9)
• devm_ioremap_wc(9)
• devm_iounmap(9)
• devm_ioremap_resource_wc(9)
• devm_ioport_map(9)
• devm_ioport_unmap(9)
• devm_arch_phys_wc_add(9)
• devm_arch_io_reserve_memtype_wc(9)

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🎀 that's the whole page, you ate that. go forth and map responsibly.

ok bye ily, this came from ./lib, October 2026 version, and yes the footer really does say devm_ioremap_resource(9) again — she's consistent 💖✨🦋