of_property_read_reg(9)

💖 of_property_read_reg(9) 💖

okay so bestie, welcome to the Kernel API Manual — section 9, kernel city, population: this function 🎀. We're talking about of_property_read_reg, and yes it's a mouthful, but it's literally just a little lookup gremlin for device-tree "reg" entries. Let's get into it ✨

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🌸 NAME 🌸

of_property_read_reg — grab the "reg" entry at the index you want, without translating it. raw dogging the address, no conversion, no glow-up 💅

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🦋 SYNOPSIS 🦋

int of_property_read_reg (struct device_node *np , int idx , u64 *addr ,
u64 *size );

like, that's the whole signature, no cap 🫶

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⭐ ARGUMENTS ⭐

• np — the device tree node you're pulling "reg" from. your main character node 👑
• idx — which "reg" entry index you wanna read. pick a number, any number 🎀
• addr — out-param city: the untranslated address gets returned here 💖
• size — and here's where the entry size lands, bestie 🌸

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🔥 DESCRIPTION 🔥

So here's the vibe check: it returns -EINVAL if "reg" is not found 😭. no reg, no love.

But on success it returns 0, and both addr and size come back all filled in and cute. literally the perfect little two-for-one 🍓

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🌈 SEE ALSO 🌈

go touch grass in the kernel file ./drivers/of/address.c and then go say hi to the whole friend group:

• of_translate_dma_region(9)
• of_dma_get_range(9)
• of_dma_get_max_cpu_address(9)
• of_dma_is_coherent(9)
• of_mmio_is_nonposted(9)
• of_address_to_resource(9)
• of_iomap(9)

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okay that's the whole page, bestie, you ate that 💅✨ this one lives in ./drivers/of and it's serving October 2026 energy — mwah, go read some device trees, ily 🫶🎀🦋