[PATCH 5.4 056/135] tty/serial: atmel: manage shutdown in case of RS485 or ISO7816 mode

[Greg Kroah-Hartman]

From: Nicolas Ferre <nicolas.ferre@xxxxxxxxxxxxx>

commit 04b5bfe3dc94e64d0590c54045815cb5183fb095 upstream.

In atmel_shutdown() we call atmel_stop_rx() and atmel_stop_tx() functions.
Prevent the rx restart that is implemented in RS485 or ISO7816 modes when
calling atmel_stop_tx() by using the atomic information tasklet_shutdown
that is already in place for this purpose.

Fixes: 98f2082c3ac4 ("tty/serial: atmel: enforce tasklet init and termination sequences")
Signed-off-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20200210152053.8289-1-nicolas.ferre@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/tty/serial/atmel_serial.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -574,7 +574,8 @@ static void atmel_stop_tx(struct uart_po
 	atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask);
 
 	if (atmel_uart_is_half_duplex(port))
-		atmel_start_rx(port);
+		if (!atomic_read(&atmel_port->tasklet_shutdown))
+			atmel_start_rx(port);
 
 }