ksz8_r_phy_bmcr(9)

📦 version 7.3.1, in nixpkgs unstable

💅 ksz8_r_phy_bmcr — like, the Kernel API Manual page for it (section 9, bestie)

okay so welcome to the group chat, the manual page is literally called ksz8_r_phy_bmcr and it lives in the Kernel API Manual, section 9. pull up a chair 🎀

✨ NAME ✨

ksz8_r_phy_bmcr — okay so what this icon does is it translates stuff and then reads from the SMI interface over to a MIIM PHY Basic mode control register (that's Reg. 0, mwah 💋). translation AND reading, she's multifaceted.

🌸 SYNOPSIS 🌸

int ksz8_r_phy_bmcr (struct ksz_device *dev , u16 port , u16 *val );

🦋 ARGUMENTS 🦋

  • dev — the KSZ device instance, like the main character in question 👑
  • port — the port number you want read. yes, that one.
  • val — the value that got read out of the SMI interface. it lives here now.

💖 DESCRIPTION 💖

so basically this function reads the SMI interface and then translates the hardware register bit values into their corresponding control settings for a MIIM PHY Basic mode control register. it's giving translator era. she's fluent 💅

🧚 MIIM Bit Mapping Comparison between KSZ8794 and KSZ8873 🧚

this is the part where you sit up straight, bestie — putting it in list form so your brain doesn't short-circuit:

  • Bit 15 - Soft Reset — KSZ8794: 0xF/4 · KSZ8873: Not supported 😭
  • Bit 14 - Loopback — KSZ8794: 0xD/0 (MAC), 0xF/7 (PHY) · KSZ8873: ~ 0xD/0 (PHY)
  • Bit 13 - Force 100 — KSZ8794: 0xC/6 · KSZ8873: = 0xC/6
  • Bit 12 - AN Enable — KSZ8794: 0xC/7 (reverse logic 👀) · KSZ8873: ~ 0xC/7
  • Bit 11 - Power Down — KSZ8794: 0xD/3 · KSZ8873: = 0xD/3
  • Bit 10 - PHY Isolate — KSZ8794: 0xF/5 · KSZ8873: Not supported
  • Bit 9 - Restart AN — KSZ8794: 0xD/5 · KSZ8873: = 0xD/5
  • Bit 8 - Force Full-Duplex — KSZ8794: 0xC/5 · KSZ8873: = 0xC/5
  • Bit 7 - Collision Test/Res. — KSZ8794: Not supported · KSZ8873: Not supported 💀 (both of them, iconic flop)
  • Bit 6 - Reserved — KSZ8794: Not supported · KSZ8873: Not supported
  • Bit 5 - Hp_mdix — KSZ8794: 0x9/7 · KSZ8873: ~ 0xF/7
  • Bit 4 - Force MDI — KSZ8794: 0xD/1 · KSZ8873: = 0xD/1
  • Bit 3 - Disable MDIX — KSZ8794: 0xD/2 · KSZ8873: = 0xD/2
  • Bit 2 - Disable Far-End F. — KSZ8794: ???? 🤷‍♀️ · KSZ8873: 0xD/4
  • Bit 1 - Disable Transmit — KSZ8794: 0xD/6 · KSZ8873: = 0xD/6
  • Bit 0 - Disable LED — KSZ8794: 0xD/7 · KSZ8873: = 0xD/7

🔥 RETURN 🔥

  • 0 on success 🎉
  • an error code on failure 😭

🌈 SEE ALSO 🌈

go read the kernel file ./drivers/net/dsa/microchip/ksz8.c (iykyk) and also these besties:

fr fr read the whole list, don't skip. they're all in the same friend group and it would be rude. 🫶

okay that's the whole page, mwah 💋 this came from ./drivers/net/dsa/microchip, dated October 2026 — and honestly? slay. periodt. 🍓💜

📦 where this page comes from