serial: imx: set receiver level before starting uart

PATCH New Stefan Eichenberger 1 participant 1 message Jun 21, 2024

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Arm i.MX and Layerscape TTY layer and serial drivers

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Stefan Eichenberger

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2024-06-21 15:38 UTC #0 lore raw

PATCH 1/1 serial: imx: set receiver level before starting uart

From: Stefan Eichenberger <[email protected]>

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 <[email protected]>

---
 drivers/tty/serial/imx.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

drivers/tty/serial/imx.c +3 -1

index 2eb22594960f3..f4f40c9373c2f 100644
@@ -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;
 }

Signature · 1 line

2.43.0