Commit 9f77d192 authored by Erwan Le Ray's avatar Erwan Le Ray Committed by Greg Kroah-Hartman
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serial: stm32: add FIFO flush when port is closed 



Transmission complete error is sent when ISR_TC is not set. If port closure
is requested despite data in TDR / TX FIFO has not been sent (because of
flow control), ISR_TC is not set and error message is sent on port closure
but also when a new port is opened.

Flush the data when port is closed, so the error isn't printed twice upon
next port opening.

Fixes: 64c32eab ("serial: stm32: Add support of TC bit status check")
Signed-off-by: default avatarErwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-12-erwan.leray@foss.st.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 315e2d8a

drivers/tty/serial/stm32-usart.c

+5 −0
Original line number Diff line number Diff line
@@ -691,6 +691,11 @@ static void stm32_usart_shutdown(struct uart_port *port) 
	if (ret)

		dev_err(port->dev, "Transmission is not complete\n");



	/* flush RX & TX FIFO */

	if (ofs->rqr != UNDEF_REG)

		writel_relaxed(USART_RQR_TXFRQ | USART_RQR_RXFRQ,

			       port->membase + ofs->rqr);



	stm32_usart_clr_bits(port, ofs->cr1, val);



	free_irq(port->irq, port);