spi_nor_otp_read_secr(9)

💅 spi_nor_otp_read_secr(9) — the Kernel API Manual, bestie edition 🎀

okay so this is spi_nor_otp_read_secr from the Kernel API Manual and she is lowkey iconic — she reads a security register for you, no cap ✨

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✨ NAME ✨

spi_nor_otp_read_secr — read security register 🦋

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🌸 SYNOPSIS 🌸

int spi_nor_otp_read_secr (struct spi_nor *nor , loff_t addr , size_t
len , u8 *buf );

literally that's the whole signature, copy it exactly pls 🙈

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💖 ARGUMENTS 💖

• nor — pointer to struct spi_nor, the main character of this whole operation 👑
• addr — the offset to read from, i.e. where the tea is located 🍓
• len — number of bytes to read, so like how much tea you're grabbing 🫶
• buf — pointer to dst buffer, the lil basket where your bytes go 💅

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🧚 DESCRIPTION 🧚

So here's the vibe: this reads a security register by using the SPINOR_OP_RSECR commands. That's it, that's the job ✨

Now for the lore: in Winbond/GigaDevice datasheets the term "security register" stands for an one-time-programmable memory area, consisting of multiple bytes (usually 256). So one "security register" maps to one OTP region. iykyk 💜

This method is used on GigaDevice and Winbond flashes. Only those two, fr fr 🔥

⚠️ Please note, the read must not span multiple registers. Like, do not do that. Respect the boundaries bestie 💀

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🌈 RETURN 🌈

number of bytes read successfully, -errno otherwise 😭 — so you either get your byte count or you get told off with an error code, there is no third option 🎀

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⭐ SEE ALSO ⭐

Kernel file ./drivers/mtd/spi-nor/otp.c — go read the source, she's right there 🦋

• spi_nor_otp_write_secr(9)
• spi_nor_otp_erase_secr(9)
• spi_nor_otp_lock_sr2(9)
• spi_nor_otp_is_locked_sr2(9)

the whole OTP friend group honestly, obsessed with them 💖

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and that's the page!! brought to you by the fine folks over at ./drivers/mtd/spi-nor, dated October 2026 — mwah, love u, go read ur security registers responsibly 🧚‍♀️💅🌸