__phy_set_bits(9)

💅 __phy_set_bits(9)

okay so bestie, welcome to the kernel API manual page for __phy_set_bits(9) — yes the double underscore one, we'll get to why that matters (spoiler: it's a locking thing 🫶). Grab a lil snack, this one's short but important ✨

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✨ NAME ✨

__phy_set_bits — literally just a convenience function for setting bits in a PHY register 🎀 no cap, that's the whole vibe

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🌸 SYNOPSIS 🌸

int __phy_set_bits (struct phy_device *phydev , u32 regnum , u16 val );

it returns an int, it takes three args, it's giving "small function, big responsibilities" energy 💅

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🦋 ARGUMENTS 🦋

• phydev — the phy_device struct 💖 this is your PHY device, your main character, the whole reason we're here
• regnum — register number to write ✍️ a u32, and this is which register we're poking
• val — bits to set 🔥 a u16, the actual bits going up to 1

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👑 DESCRIPTION 👑

so here's the tea, and it is important tea: the caller must have taken the MDIO bus lock. 🔒

like, that's it, that's the description. but do not skim past it bestie!! that's the whole reason this function has the double underscore prefix — you are the one holding the lock, so there's no internal locking happening for you. if you didn't take the lock, you are in the danger zone 💀

🫶 reminder: caller takes the MDIO bus lock. mdio bus lock = taken. by the caller. that's you. periodt.

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🧚 SEE ALSO 🧚

the full friend group, no one left out, all of these:

Kernel file ./include/linux/phy.h enum phy_interface_t(9), phy_modes(9), rgmii_clock(9), struct mdio_bus_stats(9), struct mii_bus(9), mdiobus_alloc(9), enum phy_state(9), struct phy_c45_device_ids(9), struct phy_oatc14_sqi_capability(9), struct phy_device(9), struct phy_tdr_config(9), enum link_inband_signalling(9), struct phy_plca_cfg(9), struct phy_plca_status(9), struct phy_led(9), struct phy_mse_capability(9), struct phy_mse_snapshot(9), struct phy_driver(9), phy_id_compare(9), phy_id_compare_vendor(9), phy_id_compare_model(9), phydev_id_compare(9), phy_is_started(9), phy_driver_is_genphy(9), phy_disable_eee_mode(9), phy_can_wakeup(9), phy_may_wakeup(9), phy_read(9), __phy_read(9), phy_write(9), __phy_write(9), __phy_modify_changed(9), phy_read_mmd_poll_timeout(9), __phy_clear_bits(9), phy_set_bits(9), phy_clear_bits(9), __phy_set_bits_mmd(9), __phy_clear_bits_mmd(9), phy_set_bits_mmd(9), phy_clear_bits_mmd(9), phy_interrupt_is_valid(9), phy_polling_mode(9), phy_has_hwtstamp(9), phy_has_rxtstamp(9), phy_has_tsinfo(9), phy_has_txtstamp(9), phy_is_default_hwtstamp(9), phy_on_sfp(9), phy_interface_mode_is_rgmii(9), phy_interface_mode_is_8023z(9), phy_interface_is_rgmii(9), phy_is_pseudo_fixed_link(9), phy_module_driver(9)

like I said. everybody. the whole gc 😭💜

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🌈 okay that's the page!! shoutout to ./include/linux for being the source, this one's dated October 2026, and it's __phy_set_bits(9) from the Kernel API Manual — slay, iconic, remember to hold that MDIO bus lock bestie 💅✨