mdiobus_c45_write_nested(9)

🌸 NAME 🌸

okay bestie, welcome to the mdiobus_c45_write_nested(9) page from the Kernel API Manual 💅 — this one is the nested version of the mdiobus_c45_write function. Nested! We love a layered moment. 🎀

✨ SYNOPSIS ✨

int mdiobus_c45_write_nested (struct mii_bus *bus , int addr , int devad , u32 regnum , u16 val );

🎀 ARGUMENTS 🎀

• bus — the mii_bus struct 🚌
• addr — the phy address 📍
• devad — device address to read (that's the man page's wording, bestie — keeping it exactly) 👀
• regnum — register number to write ✍️
• val — value to write to regnum 💌

🌈 RETURN 🌈

Zero if successful 😌; negative error code on failure 😭. That's the vibe check, fr fr.

💖 DESCRIPTION 💖

So in case of nested MDIO bus access, this avoids lockdep false positives by using mutex_lock_nested. Lockdep stays unbothered, the nested access stays iconic. Periodt. 🦋

⚠️ NOTE ⚠️

MUST NOT be called from interrupt context, because the bus read/write functions may wait for an interrupt to conclude the operation. Not me stressing this enough: interrupt context is a no-go, bestie. 💀

🔗 SEE ALSO 🔗

Kernel file: ./drivers/net/phy/mdio_bus.c

• __mdiobus_read(9)
• __mdiobus_write(9)
• __mdiobus_modify_changed(9)
• __mdiobus_c45_read(9)
• __mdiobus_c45_write(9)
• __mdiobus_c45_modify_changed(9)
• mdiobus_read_nested(9)
• mdiobus_read(9)
• mdiobus_c45_read(9)
• mdiobus_c45_read_nested(9)
• mdiobus_write_nested(9)
• mdiobus_write(9)
• mdiobus_c45_write(9)
• mdiobus_modify(9)
• mdiobus_c45_modify(9)
• mdiobus_modify_changed(9)
• mdiobus_c45_modify_changed(9)

cute sign-off time 🫶 source/version: ./drivers/net/phy; date: October 2026; page: mdiobus_c45_write_nested(9). mwah 💖