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

[PATCH] 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.
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@cogentembedded.com>
CC: stable@vger.kernel.org

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

 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;
 	}
 

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

[Sergei Shtylyov]

Hello.

On 5/28/2016 11:51 PM, Sergei Shtylyov wrote:

> 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.
> We  should rely on the platform IRQ resource in this case, not return 0,
> especially as 0 can be a valid  IRQ resource too...

    Actually, I wanted to say that returning 0 on error makes the error check 
unnecessarily complex and error prone bu fogrgot about that when writing the 
changelog. Let me know what you think...

> Fixes: aff008ad813c ("platform_get_irq: Revert to platform_get_resource if of_irq_get fails")
> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
> CC: stable@vger.kernel.org

[...]

MBR, Sergei