serial8250_em485_init(9)

okay so bestie, welcome to serial8250_em485_init(9) from the Kernel API Manual — the page where we put a uart_8250_port into rs485 emulating and make RTS do its lil timing dance 💅✨

✨ NAME ✨

serial8250_em485_init — put uart_8250_port into rs485 emulating 🦋

🎀 SYNOPSIS 🎀

int serial8250_em485_init (struct uart_8250_port *p );

💖 ARGUMENTS 💖

• p — the uart_8250_port port instance, aka the main character we're setting up 🫶

🌸 DESCRIPTION 🌸

okay so this function is literally used to start rs485 software emulating on the struct uart_8250_port* p. Namely, RTS is switched before/after transmission 🔥

The function is idempotent, so it is safe to call it multiple times. No cap — call it again, it's fine 💅

🚨 bestie, important warning: the caller MUST enable interrupt on empty shift register before calling serial8250_em485_init. This interrupt is not a part of 8250 standard, but implementation defined 👑

The function is supposed to be called from .rs485_config callback or from any other callback protected with p->port.lock spinlock 🧚

See also serial8250_em485_destroy — gotta wave at the destroy bestie too 💜

Return 0 - success, -errno - otherwise 🍓

🌈 SEE ALSO 🌈

• Kernel file ./drivers/tty/serial/8250/8250_port.c
• serial8250_em485_destroy(9)
• serial8250_em485_config(9)
• serial8250_em485_stop_tx(9)
• serial8250_em485_start_tx(9)

big kiss from the source/version ./drivers/tty/serial/8250, dated October 2026 — bye bestie, go make those RTS flips iconic 💖🌈