phy_modify_mmd_changed(9)

📦 version 7.3.1, in nixpkgs unstable

💖 phy_modify_mmd_changed — NAME energy 💖

okay so welcome to the Kernel API Manual, bestie 🎀 and today's main character is phy_modify_mmd_changed — literally the function for modifying a register on an MMD. that's it, that's the vibe. ✨

✨ SYNOPSIS ✨

int phy_modify_mmd_changed (struct phy_device *phydev , int devad , u32
regnum , u16 mask , u16 set );

🌸 ARGUMENTS 🌸

  • phydev — the phy_device struct, aka the whole reason we're here 🫶
  • devad — the MMD containing the register you wanna modify
  • regnum — the register number to modify, yeah we're getting specific
  • mask — bit mask of bits to clear 🔥
  • set — the new value of the bits set in mask that get written to regnum — so mask picks the seats, set decides who's sitting in them 💅

⚠️ NOTE ⚠️

MUST NOT be called from interrupt context, bestie 😭 because the bus read/write functions may wait for an interrupt to conclude the operation. like, it'll just be sitting there waiting, and that's not the moment. periodt.

Return values, listen up: it returns a negative errno, or 0 if there was no change, and 1 in case of change. lowkey obsessed with a function that tells you whether it actually did anything 🌈

🦋 SEE ALSO 🦋

Kernel file ./drivers/net/phy/phy-core.c, plus the whole friend group:

and that's the page, bestie 🧚 source lives at ./drivers/net/phy, dated October 2026 — mwah, slay, go modify some registers responsibly 💜👑

📦 where this page comes from