diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 4c217fb35bcb..7a46d7ba967e 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -105,9 +105,7 @@ static int stm32_config_rs485(struct uart_port *port,
 	struct stm32_usart_config *cfg = &stm32_port->info->cfg;
 	u32 usartdiv, baud, cr1, cr3;
 	bool over8;
-	unsigned long flags;
 
-	spin_lock_irqsave(&port->lock, flags);
 	stm32_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
 
 	port->rs485 = *rs485conf;
@@ -147,7 +145,6 @@ static int stm32_config_rs485(struct uart_port *port,
 	}
 
 	stm32_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
-	spin_unlock_irqrestore(&port->lock, flags);
 
 	return 0;
 }