diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 767ff9fdb2e5..bf51e2152dd5 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -743,7 +743,6 @@ static void stm32_usart_transmit_chars(struct uart_port *port)
 		stm32_usart_tx_interrupt_disable(port);
 		if (!stm32_port->hw_flow_control &&
 		    port->rs485.flags & SER_RS485_ENABLED) {
-			stm32_port->txdone = true;
 			stm32_usart_tc_interrupt_enable(port);
 		}
 	}
diff --git a/drivers/tty/serial/stm32-usart.h b/drivers/tty/serial/stm32-usart.h
index 0ec41a732c88..903285b5aea7 100644
--- a/drivers/tty/serial/stm32-usart.h
+++ b/drivers/tty/serial/stm32-usart.h
@@ -203,7 +203,6 @@ struct stm32_port {
 	bool hw_flow_control;
 	bool swap;		 /* swap RX & TX pins */
 	bool fifoen;
-	bool txdone;
 	int rxftcfg;		/* RX FIFO threshold CFG      */
 	int txftcfg;		/* TX FIFO threshold CFG      */
 	bool wakeup_src;