[PATCH v1] serial: imx: set receiver level before starting uart

[Stefan Eichenberger <eichest@gmail.com>]

From: Stefan Eichenberger <stefan.eichenberger@toradex.com>

Set the receiver level to something > 0 before calling imx_uart_start_rx
in rs485_config. This is necessary to avoid an interrupt storm that
might prevent the system from booting. This was seen on an i.MX7 device
when the rs485-rts-active-low property was active in the device tree.

Fixes: 6d215f83e5fc ("serial: imx: warn user when using unsupported configuration")
Signed-off-by: Stefan Eichenberger <stefan.eichenberger@toradex.com>
---
 drivers/tty/serial/imx.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 2eb22594960f3..f4f40c9373c2f 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -1952,8 +1952,10 @@ static int imx_uart_rs485_config(struct uart_port *port, struct ktermios *termio
 
 	/* Make sure Rx is enabled in case Tx is active with Rx disabled */
 	if (!(rs485conf->flags & SER_RS485_ENABLED) ||
-	    rs485conf->flags & SER_RS485_RX_DURING_TX)
+	    rs485conf->flags & SER_RS485_RX_DURING_TX) {
+		imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT);
 		imx_uart_start_rx(port);
+	}
 
 	return 0;
 }
-- 
2.43.0