From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752189AbbANUFZ (ORCPT ); Wed, 14 Jan 2015 15:05:25 -0500 Received: from mail-gw2-out.broadcom.com ([216.31.210.63]:22859 "EHLO mail-gw2-out.broadcom.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751225AbbANUFW (ORCPT ); Wed, 14 Jan 2015 15:05:22 -0500 X-IronPort-AV: E=Sophos;i="5.07,757,1413270000"; d="scan'208";a="54818385" Message-ID: <54B6CC00.3050609@broadcom.com> Date: Wed, 14 Jan 2015 12:05:20 -0800 From: Ray Jui User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: =?windows-1252?Q?Uwe_Kleine-K=F6nig?= CC: Wolfram Sang , Rob Herring , Pawel Moll , Mark Rutland , "Ian Campbell" , Kumar Gala , Grant Likely , Christian Daudt , Matt Porter , Florian Fainelli , Russell King , "Scott Branden" , , , , , Subject: Re: [PATCH v3 2/3] i2c: iproc: Add Broadcom iProc I2C Driver References: <1418183832-24793-1-git-send-email-rjui@broadcom.com> <1418183832-24793-3-git-send-email-rjui@broadcom.com> <20150113225012.GK22880@pengutronix.de> <54B5D0F9.8030902@broadcom.com> <20150114075137.GL22880@pengutronix.de> In-Reply-To: <20150114075137.GL22880@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 1/13/2015 11:51 PM, Uwe Kleine-König wrote: > Hello, > > On Tue, Jan 13, 2015 at 06:14:17PM -0800, Ray Jui wrote: >>>> + irq = platform_get_irq(pdev, 0); >>>> + if (irq < 0) { >>> irq == 0 should be handled as error, too. >>> >> Ah. I thought zero is a valid global interrupt number, and I see other >> drivers checking against < 0 as well. Is my understanding incorrect? > These are wrong, too. 0 should never be a valid interrupt number. There > are some exceptions but mostly for historic reasons. The right handling > is used for example in drivers/i2c/busses/i2c-efm32.c. > Okay. Will check against <= 0. Thanks. >>>> + dev_err(dev->device, "no irq resource\n"); >>>> + return irq; >>>> + } >> [...] >>>> +static int bcm_iproc_i2c_remove(struct platform_device *pdev) >>>> +{ >>>> + struct bcm_iproc_i2c_dev *dev = platform_get_drvdata(pdev); >>>> + >>>> + i2c_del_adapter(&dev->adapter); >>>> + bcm_iproc_i2c_disable(dev); >>> I think you have a problem here if bcm_iproc_i2c_remove is called while >>> an irq is still being serviced. I'm not sure how to prevent this >>> properly for a shared interrupt. >>> >> Can I grab i2c_lock_adapter to ensure the bus is locked (so there's no >> outstanding transactions or IRQs by the time we remove the adapter)? But >> I see no I2C bus driver does this in their remove function... > The problem I pointed out is the reason for some driver authors not to > use devm_request_irq. If you use plain request_irq and the matching > free_irq in the .remove callback you can be sure that the irq isn't > running any more as soon as free_irq returns. > Okay. Will change to use request_irq and make sure that it's freed in the remove function. Also, the interrupt is dedicated to the I2C controller, so I'll remove the IRQF_SHARED flag. > BTW, if you use vim, you can add > > set cinoptions=(,: > if has("autocmd") > filetype plugin indent on > endif > > to your .vimrc. Then while typing vim does the indention right and > consistent, and with the = command you can reindent. > Wow this is excellent! Just tried and it works perfectly. Thanks a lot!!! > Best regards > Uwe >