get_phy_device(9)

📦 version 7.3.1, in nixpkgs unstable

💖 get_phy_device(9) — Kernel API Manual 💖

okay so bestie, welcome to the glow-up of get_phy_device from the Kernel API Manual — she reads the PHY device you point at and hands you back her @phy_device struct. genuinely iconic behaviour. let's get into it 🫶

✨ SYNOPSIS ✨

struct phy_device * get_phy_device (struct mii_bus *bus , int addr ,
       bool is_c45 );

🎀 ARGUMENTS 🎀

  • bus — the target MII bus. like, the bus she's gonna go snoop on ✨
  • addr — PHY address on the MII bus. that's where on the bus, bestie 📍
  • is_c45 — if this is true, the PHY uses the 802.3 clause 45 protocol. true = clause 45 energy, false = not that 💅

🌸 DESCRIPTION 🌸

So the whole vibe is: probe for a PHY at addr on bus. that's the assignment, and she ate.

When you're probing for a clause 22 PHY, she reads the ID registers. if we find a valid ID, she allocates and returns a struct phy_device. periodt 💅

When you're probing for a clause 45 PHY, she reads the "devices in package" registers. if the "devices in package" appears valid, she reads the ID registers for each MMD, then allocates and returns a struct phy_device. multiple MMDs, one struct, no notes 🦋

And what does she give back? listen closely bestie:

  • an allocated struct phy_device on success 👑
  • -ENODEV if there is no PHY present 😭
  • -EIO on bus access error 💀
ngl, those two error codes matter — -ENODEV means "nobody home", -EIO means "the bus itself fumbled". don't mix them up fr fr.

🌈 SEE ALSO 🌈

Kernel file ./drivers/net/phy/phy_device.c, plus this whole friend group of (9) pages — every single one, no skipping 🧚:

that's the whole page, bestie — go probe something valid 💖

source/version: ./drivers/net/phy · dated October 2026 · and yeah, the title up top is get_phy_device(9), slay 🌟
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