[PATCH] serial: stm32: avoid kernel warning on absence of optional IRQ

[Holger Assmann]

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

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 8602ff357321..b77b41c768fb 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -962,7 +962,7 @@ static int stm32_init_port(struct stm32_port *stm32port,
 		return ret;
 
 	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;
 	}
-- 
2.20.1