serial: vt8500: Use platform_get_irq() to get the interrupt

platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static
allocation of IRQ resources in DT core code, this causes an issue
when using hierarchical interrupt domains using "interrupts" property
in the node as this bypasses the hierarchical setup and messes up the
irq chaining.

In preparation for removal of static setup of IRQ resource from DT core
code use platform_get_irq().

Signed-off-by: Lad Prabhakar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: prabhakarlad

drivers/tty/serial/vt8500_serial.c

@@ -621,21 +621,25 @@ static const struct of_device_id wmt_dt_ids[] = {
 static int vt8500_serial_probe(struct platform_device *pdev)
 {
 	struct vt8500_port *vt8500_port;
-	struct resource *mmres, *irqres;
+	struct resource *mmres;
 	struct device_node *np = pdev->dev.of_node;
 	const unsigned int *flags;
 	int ret;
 	int port;
+	int irq;
 
 	flags = of_device_get_match_data(&pdev->dev);
 	if (!flags)
 		return -EINVAL;
 
 	mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	irqres = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
-	if (!mmres || !irqres)
+	if (!mmres)
 		return -ENODEV;
 
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
 	if (np) {
 		port = of_alias_get_id(np, "serial");
 		if (port >= VT8500_MAX_PORTS)
@@ -688,7 +692,7 @@ static int vt8500_serial_probe(struct platform_device *pdev)
 	vt8500_port->uart.type = PORT_VT8500;
 	vt8500_port->uart.iotype = UPIO_MEM;
 	vt8500_port->uart.mapbase = mmres->start;
-	vt8500_port->uart.irq = irqres->start;
+	vt8500_port->uart.irq = irq;
 	vt8500_port->uart.fifosize = 16;
 	vt8500_port->uart.ops = &vt8500_uart_pops;
 	vt8500_port->uart.line = port;