mdiobus_write_nested(9)

📦 version 7.3.1, in nixpkgs unstable

✨ mdiobus_write_nested(9) ✨

okay so bestie, welcome to the Kernel API Manual 💖 and today's main character is mdiobus_write_nested — literally the nested version of the mdiobus_write function, no cap 🫶

🌸 NAME 🌸

mdiobus_write_nested — it's giving "nested version of the mdiobus_write function" ✨

🦋 SYNOPSIS 🦋

int mdiobus_write_nested (struct mii_bus *bus , int addr , u32 regnum ,
       u16 val );

like, that's the whole signature, slay 💅

🎀 ARGUMENTS 🎀

  • bus — the mii_bus struct, your bus babe, the whole vibe 🌈
  • addr — the phy address, iykyk 👑
  • regnum — register number to write, like the exact drawer you're putting stuff in 🍓
  • val — value to write to regnum, the actual thing going in 🔥

⭐ RETURN ⭐

Zero if successful 😌 negative error code on failure 😭

like, zero = ate, negative = it's giving disaster fr fr 💀

💜 DESCRIPTION 💜

In case of nested MDIO bus access, avoid lockdep false positives by using mutex_lock_nested. ✨

lowkey iconic that this is the entire reason this function exists — it's just out here protecting you from fake lockdep drama 🧚 no cap 💅

🩷 NOTE 🩷

MUST NOT be called from interrupt context, because the bus read/write functions may wait for an interrupt to conclude the operation. 🚨

like seriously bestie, do NOT do this from interrupt context — highkey it will not end well for you 🙈💀

🌈 SEE ALSO 🌈

Kernel file ./drivers/net/phy/mdio_bus.c plus the whole squad, and yes I'm listing every single one because we don't skip anyone in this house 🫶:

and that's the page!! 🎀 sign-off time: this little baddie lives in ./drivers/net/phy, the version stamp says October 2026, and the manual name is mdiobus_write_nested(9) — go forth and write your registers responsibly bestie, mwah 💋💖✨

📦 where this page comes from