From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grygorii Strashko Subject: Re: [1/5] i2c: i2c-davinci: switch to use platform_get_irq Date: Fri, 21 Nov 2014 16:59:19 +0200 Message-ID: <546F5347.7010600@ti.com> References: <1416477788-5544-2-git-send-email-grygorii.strashko@ti.com> <20141120214838.GA346@pengutronix.de> <546F1B7D.1020209@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Rob Herring Cc: =?UTF-8?B?VXdlIEtsZWluZS1Lw7ZuaWc=?= , Grant Likely , Wolfram Sang , "linux-i2c@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Sekhar Nori , Kevin Hilman , Santosh Shilimkar , Murali Karicheri List-Id: linux-i2c@vger.kernel.org On 11/21/2014 04:03 PM, Rob Herring wrote: > On Fri, Nov 21, 2014 at 5:01 AM, Grygorii Strashko > wrote: >> On 11/20/2014 11:48 PM, Uwe Kleine-K=C3=B6nig 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 >>>> CC: Kevin Hilman >>>> CC: Santosh Shilimkar >>>> CC: Murali Karicheri >>>> Signed-off-by: Grygorii Strashko >>>> --- >>>> 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 =3D platform_get_resource(pdev, IORESOURCE_IRQ, 0); >>>> - if (!irq) { >>>> - dev_err(&pdev->dev, "no irq resource?\n"); >>>> - return -ENODEV; >>>> + irq =3D platform_get_irq(pdev, 0); >>> One bad thing about platform_get_irq is its unusual handling of irq= =3D0. >>> I'm pretty sure you don't want to use this value, so adding somethi= ng >>> like: >>> >>> if (!irq) >>> irq =3D -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 <=3D 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 > needed. Thanks for your comment. regards, -grygorii