From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ray Jui Subject: Re: [PATCH v3 2/3] i2c: iproc: Add Broadcom iProc I2C Driver Date: Wed, 14 Jan 2015 12:05:20 -0800 Message-ID: <54B6CC00.3050609@broadcom.com> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20150114075137.GL22880@pengutronix.de> Sender: linux-kernel-owner@vger.kernel.org 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 , linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, bcm-kernel-feedback-list@broadcom.com, devicetree@vger.kernel.org List-Id: linux-i2c@vger.kernel.org On 1/13/2015 11:51 PM, Uwe Kleine-K=F6nig wrote: > Hello, >=20 > On Tue, Jan 13, 2015 at 06:14:17PM -0800, Ray Jui wrote: >>>> + irq =3D platform_get_irq(pdev, 0); >>>> + if (irq < 0) { >>> irq =3D=3D 0 should be handled as error, too. >>> >> Ah. I thought zero is a valid global interrupt number, and I see oth= er >> drivers checking against < 0 as well. Is my understanding incorrect? > These are wrong, too. 0 should never be a valid interrupt number. The= re > are some exceptions but mostly for historic reasons. The right handli= ng > is used for example in drivers/i2c/busses/i2c-efm32.c. >=20 Okay. Will check against <=3D 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 =3D 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 w= hile >>> 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 t= o > 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. >=20 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 >=20 > set cinoptions=3D(,: > if has("autocmd") > filetype plugin indent on > endif >=20 > to your .vimrc. Then while typing vim does the indention right and > consistent, and with the =3D command you can reindent. >=20 Wow this is excellent! Just tried and it works perfectly. Thanks a lot!= !! > Best regards > Uwe >=20