USB: gpio_vbus: handle IRQ flags properly

Currently, 'res->flags' handlings are wrong in three respects:
* the driver _modifies_ the contents of platform data
* res->flags is set up, but not used anywhere in the driver
* request_irq() always takes VBUS_IRQ_FLAGS, regardless of refs->flags

This patch tries to fix this with a policy: If a platform IRQ resource
is available, give preference to its IRQ flag(s) over a default one
(VBUS_IRQ_FLAGS).

Signed-off-by: Shinya Kuribayashi <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/otg/gpio_vbus.c

···
 	struct gpio_vbus_data *gpio_vbus;
 	struct resource *res;
 	int err, gpio, irq;
+	unsigned long irqflags;
 
 	if (!pdata || !gpio_is_valid(pdata->gpio_vbus))
 		return -EINVAL;
···
 	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 	if (res) {
 		irq = res->start;
-		res->flags &= IRQF_TRIGGER_MASK;
-		res->flags |= IRQF_SHARED;
-	} else
+		irqflags = (res->flags & IRQF_TRIGGER_MASK) | IRQF_SHARED;
+	} else {
 		irq = gpio_to_irq(gpio);
+		irqflags = VBUS_IRQ_FLAGS;
+	}
 
 	gpio_vbus->irq = irq;
 
···
 		gpio_direction_output(gpio, pdata->gpio_pullup_inverted);
 	}
 
-	err = request_irq(irq, gpio_vbus_irq, VBUS_IRQ_FLAGS,
-		"vbus_detect", pdev);
+	err = request_irq(irq, gpio_vbus_irq, irqflags, "vbus_detect", pdev);
 	if (err) {
 		dev_err(&pdev->dev, "can't request irq %i, err: %d\n",
 			irq, err);