5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Stefan Eichenberger <stefan.eichenberger@xxxxxxxxxxx>
commit a81dbd0463eca317eee44985a66aa6cc2ce5c101 upstream.
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")
Cc: stable <stable@xxxxxxxxxx>
Signed-off-by: Stefan Eichenberger <stefan.eichenberger@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240621153829.183780-1-eichest@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/imx.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -1887,8 +1887,10 @@ static int imx_uart_rs485_config(struct
/* 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);
+ }
port->rs485 = *rs485conf;
