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SubjectRe: [1/5] i2c: i2c-davinci: switch to use platform_get_irq
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@ti.com>
> CC: Kevin Hilman <khilman@deeprootsystems.com>
> CC: Santosh Shilimkar <ssantosh@kernel.org>
> CC: Murali Karicheri <m-karicheri2@ti.com>
> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
> ---
> 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
like:

if (!irq)
irq = -ENXIO

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.

> + if (irq < 0) {
> + dev_err(&pdev->dev, "can't get irq resource ret=%d\n", irq);
Please don't print an error if irq=-EPROBE_DEFER.

> + return irq;
> }

--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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