[PATCH v2] platform_get_irq: Revert to platform_get_resource if of_irq_get fails

[Guenter Roeck <linux@roeck-us.net>]

Commits 9ec36ca (of/irq: do irq resolution in platform_get_irq)
and ad69674 (of/irq: do irq resolution in platform_get_irq_byname)
change the semantics of platform_get_irq and platform_get_irq_byname
to always rely on devicetree information if devicetree is enabled
and if a devicetree node is attached to the device. The functions
now return an error if the devicetree data does not include interrupt
information, even if the information is available as platform resource
data.

This causes mfd client drivers to fail if the interrupt number is
passed via platform resources. Therefore, if of_irq_get fails, try
platform_get_resource as method of last resort. This restores the
original functionality for drivers depending on platform resources
to get irq information.

Cc: Russell King <linux@arm.linux.org.uk>
Cc: Rob Herring <robh@kernel.org>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v2: Include change for platform_get_irq_byname
    Handle EPROBE_DEFER

It looks like v1 got lost in space, so you may not have seen it.
I am sending this patch as v2 anyway to avoid confusion, just in case
v1 shows up somewhere.

At least 9ec36ca has been applied to -stable, so if this patch is
accepted it may make sense to apply it to the same -stable releases.

 drivers/base/platform.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 9e9227e..eee48c4 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -89,8 +89,13 @@ int platform_get_irq(struct platform_device *dev, unsigned int num)
 	return dev->archdata.irqs[num];
 #else
 	struct resource *r;
-	if (IS_ENABLED(CONFIG_OF_IRQ) && dev->dev.of_node)
-		return of_irq_get(dev->dev.of_node, num);
+	if (IS_ENABLED(CONFIG_OF_IRQ) && dev->dev.of_node) {
+		int ret;
+
+		ret = of_irq_get(dev->dev.of_node, num);
+		if (ret >= 0 || ret == -EPROBE_DEFER)
+			return ret;
+	}
 
 	r = platform_get_resource(dev, IORESOURCE_IRQ, num);
 
@@ -133,8 +138,13 @@ int platform_get_irq_byname(struct platform_device *dev, const char *name)
 {
 	struct resource *r;
 
-	if (IS_ENABLED(CONFIG_OF_IRQ) && dev->dev.of_node)
-		return of_irq_get_byname(dev->dev.of_node, name);
+	if (IS_ENABLED(CONFIG_OF_IRQ) && dev->dev.of_node) {
+		int ret;
+
+		ret = of_irq_get_byname(dev->dev.of_node, name);
+		if (ret >= 0 || ret == -EPROBE_DEFER)
+			return ret;
+	}
 
 	r = platform_get_resource_byname(dev, IORESOURCE_IRQ, name);
 	return r ? r->start : -ENXIO;
-- 
1.9.1