tty/serial: atmel: manage shutdown in case of RS485 or ISO7816 mode

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.

Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>

Author: noglitch

drivers/tty/serial/atmel_serial.c

@@ -620,7 +620,9 @@ static void atmel_stop_tx(struct uart_port *port)
 	if (((port->rs485.flags & SER_RS485_ENABLED) &&
 	     !(port->rs485.flags & SER_RS485_RX_DURING_TX)) ||
 	    port->iso7816.flags & SER_ISO7816_ENABLED)
-		atmel_start_rx(port);
+		if (!atomic_read(&atmel_port->tasklet_shutdown))
+			atmel_start_rx(port);
+
 }
 
 /*