[PATCH v2] platform: don't return 0 from platform_get_irq[_byname]() on error

[Sergei Shtylyov]

of_irq_get[_byname]() return 0 iff  irq_create_of_mapping() call fails.
Returning both  error code and 0 on failure is a sign of a misdesigned API,
it makes the failure check unnecessarily complex and error prone. We should
rely  on the platform IRQ resource in this case, not return 0,  especially
as 0 can be  a valid  IRQ resource too...

Fixes: aff008ad813c ("platform_get_irq: Revert to platform_get_resource if of_irq_get fails")
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
CC: stable@xxxxxxxxxxxxxxx

---
The patch is against the 'driver-core-linus' branch of Greg KH's
'driver-core.git' repo.

See also commit 3993546646ba ("of: irq: fix of_irq_get[_byname]() kernel-doc")

Changes in version 2:
- expanded the changelog.

 drivers/base/platform.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Index: driver-core/drivers/base/platform.c
===================================================================
--- driver-core.orig/drivers/base/platform.c
+++ driver-core/drivers/base/platform.c
@@ -97,7 +97,7 @@ int platform_get_irq(struct platform_dev
 		int ret;
 
 		ret = of_irq_get(dev->dev.of_node, num);
-		if (ret >= 0 || ret == -EPROBE_DEFER)
+		if (ret > 0 || ret == -EPROBE_DEFER)
 			return ret;
 	}
 
@@ -175,7 +175,7 @@ int platform_get_irq_byname(struct platf
 		int ret;
 
 		ret = of_irq_get_byname(dev->dev.of_node, name);
-		if (ret >= 0 || ret == -EPROBE_DEFER)
+		if (ret > 0 || ret == -EPROBE_DEFER)
 			return ret;
 	}