[PATCH 5.4 164/214] serial: stm32: avoid kernel warning on absence of optional IRQ

[Greg Kroah-Hartman]

From: Holger Assmann <h.assmann@xxxxxxxxxxxxxx>

commit fdf16d78941b4f380753053d229955baddd00712 upstream.

stm32_init_port() of the stm32-usart may trigger a warning in
platform_get_irq() when the device tree specifies no wakeup interrupt.

The wakeup interrupt is usually a board-specific GPIO and the driver
functions correctly in its absence. The mainline stm32mp151.dtsi does
not specify it, so all mainline device trees trigger an unnecessary
kernel warning. Use of platform_get_irq_optional() avoids this.

Fixes: 2c58e56096dd ("serial: stm32: fix the get_irq error case")
Signed-off-by: Holger Assmann <h.assmann@xxxxxxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20200813152757.32751-1-h.assmann@xxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/tty/serial/stm32-usart.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -937,7 +937,7 @@ static int stm32_init_port(struct stm32_
 	stm32_init_rs485(port, pdev);
 
 	if (stm32port->info->cfg.has_wakeup) {
-		stm32port->wakeirq = platform_get_irq(pdev, 1);
+		stm32port->wakeirq = platform_get_irq_optional(pdev, 1);
 		if (stm32port->wakeirq <= 0 && stm32port->wakeirq != -ENXIO)
 			return stm32port->wakeirq ? : -ENODEV;
 	}