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 <andy.gross@linaro.org>
Acked-by: NRob Herring <robh@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

drivers/base/platform.c

@@ -116,6 +116,26 @@ int platform_get_irq(struct platform_device *dev, unsigned int num)
 }
 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

include/linux/platform_device.h

@@ -51,6 +51,7 @@ extern void arch_setup_pdev_archdata(struct platform_device *);
 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 *);