mux_request_port(9)

💖 mux_request_port(9) 💖

okay bestie, welcome to the Kernel API Manual entry for mux_request_port(9) — yes, the manual name is folded in right here so we didn't have to copy that header line. This one is literally about requesting memory and IO regions, and it's lowkey iconic. 🎀

✨ NAME ✨

mux_request_port — request memory and IO regions. That's the name, that's the vibe: request memory and IO regions. 💅

🌸 SYNOPSIS 🌸

Exact signature, no cap:

int mux_request_port (struct uart_port *port );

🎀 ARGUMENTS 🎀

• port — Ptr to the uart_port. Like, that's the only argument, and it's a pointer to the uart_port, fr fr. 🫶

💅 DESCRIPTION 💅

okay so mux_request_port is doing its main character thing here: it requests any memory and IO region resources required by the port. That's the whole job. Obsessed. 🔥

The failure rule is strict, bestie: if any fail, no resources should be registered when this function returns, and it should return -EBUSY on failure. Not -EAGAIN, not a little warning — -EBUSY, periodt. 💀

🚨 caveat check: on failure, nothing should be left registered, and the return value should be -EBUSY. That's the contract, and we respect it. 🙈

🦋 SEE ALSO 🦋

Kernel file ./drivers/tty/serial/mux.c — and here's the whole mux friend group, iykyk:

• get_mux_port_count(9)
• mux_tx_empty(9)
• mux_set_mctrl(9)
• mux_get_mctrl(9)
• mux_stop_tx(9)
• mux_start_tx(9)
• mux_stop_rx(9)
• mux_break_ctl(9)
• mux_write(9)
• mux_read(9)
• mux_startup(9)
• mux_shutdown(9)
• mux_set_termios(9)
• mux_type(9)
• mux_release_port(9)
• mux_config_port(9)
• mux_verify_port(9)
• mux_poll(9)
• mux_probe(9)
• mux_init(9)
• mux_exit(9)

xoxo, this page is sourced from ./drivers/tty/serial and dated October 2026 — go slay those port requests, bestie 💖✨🌈