driver-core: platform: Add platform_irq_count()

A recent patch added calls to of_irq_count() in the qcom pinctrl
drivers and that caused module build failures because
of_irq_count() is not an exported symbol. We shouldn't export
of_irq_count() to modules because it's an internal OF API that
shouldn't be used by drivers. Platform drivers should use
platform device APIs instead. Therefore, add a platform_irq_count()
API that mirrors the of_irq_count() API so that platform drivers
can stay DT agnostic.

Cc: Andy Gross <[e-mail]>
Acked-by: Rob Herring <[e-mail]>
Acked-by: Greg Kroah-Hartman <[e-mail]
Signed-off-by: Stephen Boyd <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>

drivers/base/platform.c

···
 EXPORT_SYMBOL_GPL(platform_get_irq);
 
 /**
+ * platform_irq_count - Count the number of IRQs a platform device uses
+ * @dev: platform device
+ *
+ * Return: Number of IRQs a platform device uses or EPROBE_DEFER
+ */
+int platform_irq_count(struct platform_device *dev)
+{
+	int ret, nr = 0;
+
+	while ((ret = platform_get_irq(dev, nr)) >= 0)
+		nr++;
+
+	if (ret == -EPROBE_DEFER)
+		return ret;
+
+	return nr;
+}
+EXPORT_SYMBOL_GPL(platform_irq_count);
+
+/**
  * platform_get_resource_byname - get a resource for a device by name
  * @dev: platform device
  * @type: resource type

include/linux/platform_device.h

···
 extern struct resource *platform_get_resource(struct platform_device *,
 					      unsigned int, unsigned int);
 extern int platform_get_irq(struct platform_device *, unsigned int);
+extern int platform_irq_count(struct platform_device *);
 extern struct resource *platform_get_resource_byname(struct platform_device *,
 						     unsigned int,
 						     const char *);