Re: [1/5] i2c: i2c-davinci: switch to use platform_get_irq

From: Grygorii Strashko
Date: Fri Nov 21 2014 - 09:59:45 EST

On 11/21/2014 04:03 PM, Rob Herring wrote:
On Fri, Nov 21, 2014 at 5:01 AM, Grygorii Strashko
<grygorii.strashko@xxxxxx> wrote:
On 11/20/2014 11:48 PM, Uwe Kleine-KÃnig wrote:
Hello Grygorii,

On Thu, Nov 20, 2014 at 12:03:04PM +0200, Grygorii Strashko wrote:
Switch Davinci I2C driver to use platform_get_irq(), because
- it is not recommened to use
platform_get_resource(pdev, IORESOURCE_IRQ, ..) for requesting IRQ's
resources any more, as they can be not ready yet in case of DT-booting.
- it makes code simpler

CC: Sekhar Nori <nsekhar@xxxxxx>
CC: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
CC: Santosh Shilimkar <ssantosh@xxxxxxxxxx>
CC: Murali Karicheri <m-karicheri2@xxxxxx>
Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
drivers/i2c/busses/i2c-davinci.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 4d96147..9bbfb8f 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -640,13 +640,13 @@ static int davinci_i2c_probe(struct platform_device *pdev)
struct davinci_i2c_dev *dev;
struct i2c_adapter *adap;
- struct resource *mem, *irq;
- int r;
+ struct resource *mem;
+ int r, irq;

- irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
- if (!irq) {
- dev_err(&pdev->dev, "no irq resource?\n");
- return -ENODEV;
+ irq = platform_get_irq(pdev, 0);
One bad thing about platform_get_irq is its unusual handling of irq=0.
I'm pretty sure you don't want to use this value, so adding something

if (!irq)
irq = -ENXIO

I'll add this check in driver.

would be welcome because the usual value for "invalid irq" is 0 and not
-ESOMETHING. platform_get_irq is one of the very few functions that
don't adhere to this convention. With handling <= 0 as error your code
is immune to changes in this area. Although I notice that
platform_get_irq got worse in this respect to handle -EPROBE_DEFER. hmm.

Apart from your change I wonder if platform_get_irq should handle
of_irq_get returning 0 as an error.

I think you are right and It seems like, the check for !irq should
be added/restored for OF case in platform_get_irq() too.

Changing the return values of platform_get_irq is tricky as it would
potentially break drivers because NO_IRQ can be 0 or -1 depending on
the arch. Drivers checking against specific values of NO_IRQ would
break. We've done some clean-up in this area, but I suspect more is

Thanks for your comment.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at