Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757407AbaKULBk (ORCPT ); Fri, 21 Nov 2014 06:01:40 -0500 Received: from arroyo.ext.ti.com ([192.94.94.40]:37352 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750856AbaKULBj (ORCPT ); Fri, 21 Nov 2014 06:01:39 -0500 Message-ID: <546F1B7D.1020209@ti.com> Date: Fri, 21 Nov 2014 13:01:17 +0200 From: Grygorii Strashko User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: =?windows-1252?Q?Uwe_Kleine-K=F6nig?= , Rob Herring , Grant Likely CC: Wolfram Sang , , , Sekhar Nori , Kevin Hilman , Santosh Shilimkar , Murali Karicheri Subject: Re: [1/5] i2c: i2c-davinci: switch to use platform_get_irq References: <1416477788-5544-2-git-send-email-grygorii.strashko@ti.com> <20141120214838.GA346@pengutronix.de> In-Reply-To: <20141120214838.GA346@pengutronix.de> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/20/2014 11:48 PM, Uwe Kleine-K?nig 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 = 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. 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. Also, I've simulated irq == 0 case - the .probe() failed with error -EINVAL which is returned by request_threaded_irq() because of !irq_settings_can_request(desc). i2c_davinci 2530000.i2c: failure requesting irq 0 i2c_davinci: probe of 2530000.i2c failed with error -22 I'm not sure that above will work for everyone because it depends on ARCH_IRQ_INIT_FLAGS and ARCH_IRQ_INIT_FLAGS = (IRQ_NOREQUEST | IRQ_NOPROBE) for ARM. > >> + 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. ok. regards, -grygorii -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/