cti_tristate_disable(9)

📦 version 7.3.1, in nixpkgs unstable

okay so bestie, this is cti_tristate_disable(9) from the Kernel API Manual — the function whose whole main-character job is to disable RS485 transciever tristate. 🦋✨

🌸 NAME 🌸

cti_tristate_disable - Disable RS485 transciever tristate 🎀

✨ SYNOPSIS ✨

int cti_tristate_disable (struct exar8250 *priv , unsigned int port_num
       );

🎀 ARGUMENTS 🎀

  • priv — the device's private structure. Like, it's the card's little personal diary, but make it struct exar8250 *. 🫶
  • port_num — port number to set tristate off. Girl, this is the port we're switching tristate off for. ✨

🦋 DESCRIPTION 🦋

Okay so most RS485 capable cards have a power on tristate jumper/switch that ensures the RS422/RS485 transceiver does not drive a multi-drop RS485 bus when it is not the master. 💅 When this jumper is installed the user must set the RS485 mode to Full or Half duplex to disable tristate prior to using the port. No cap.

Some Exar UARTs have an auto-tristate feature while others require setting an MPIO to disable the tristate. 🦋

🔥 RETURN 🔥

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

👑 SEE ALSO 👑

Kernel file ./drivers/tty/serial/8250/8250_exar.c, struct exar8250_board(9), and these besties:

🍓 okay that's the whole page, bestie — source/version: ./drivers/tty/serial/8250; date: October 2026. periodt 💋✨

📦 where this page comes from