Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756988AbcCaOH0 (ORCPT ); Thu, 31 Mar 2016 10:07:26 -0400 Received: from caladan.dune.hu ([78.24.191.180]:38562 "EHLO arrakis.dune.hu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756779AbcCaOHZ (ORCPT ); Thu, 31 Mar 2016 10:07:25 -0400 Subject: Re: [PATCH] mfd: mt6397: irq domain should initialize before mfd_add_devices() To: Yingjoe Chen References: <1459322708-21363-1-git-send-email-henryc.chen@mediatek.com> <56FB99DB.6010901@openwrt.org> <1459388452.18284.2.camel@mtksdaap41> <1459391533.21870.15.camel@mtksdaap41> <56FCE910.8030100@openwrt.org> <1459431711.395.6.camel@mtksdaap41> Cc: Sascha Hauer , linux-kernel@vger.kernel.org, Henry Chen , Flora Fu , linux-mediatek@lists.infradead.org, linux@roeck-us.net, Matthias Brugger , Lee Jones , linux-arm-kernel@lists.infradead.org From: John Crispin Message-ID: <56FD2F18.4050508@openwrt.org> Date: Thu, 31 Mar 2016 16:07:20 +0200 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:38.0) Gecko/20100101 Thunderbird/38.7.0 MIME-Version: 1.0 In-Reply-To: <1459431711.395.6.camel@mtksdaap41> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3059 Lines: 98 On 31/03/2016 15:41, Yingjoe Chen wrote: > On Thu, 2016-03-31 at 11:08 +0200, John Crispin wrote: >> >> On 31/03/2016 04:32, Yingjoe Chen wrote: >>> On Thu, 2016-03-31 at 09:40 +0800, Henry Chen wrote: >>>> On Wed, 2016-03-30 at 11:18 +0200, John Crispin wrote: >>>>> Hi, >>>>> >>>>> small nitpick inline >>>>> >>>>> On 30/03/2016 09:25, Henry Chen wrote: >>>>>> Some sub driver like RTC module need irq domain from parent to create >>>>>> irq mapping when driver initialize. so move mt6397_irq_init() before >>>>>> mfd_add_devices(). >>>>>> >>>>>> Signed-off-by: Henry Chen >>>>>> --- >>>>>> This patch fixed the below warning based on "Linux kernel v4.6-rc1" >>>>>> WARNING: CPU: 1 PID: 132 at kernel/mediatek/kernel/irq/irqdomain.c:471 >>>>>> irq_create_mapping+0xc4/0xd0 >>>>>> --- >>>>>> drivers/mfd/mt6397-core.c | 37 ++++++++++++++++++++++--------------- >>>>>> 1 file changed, 22 insertions(+), 15 deletions(-) >>>>>> >>>>>> diff --git a/drivers/mfd/mt6397-core.c b/drivers/mfd/mt6397-core.c >>>>>> index 8e8d932..a879223 100644 >>>>>> --- a/drivers/mfd/mt6397-core.c >>>>>> +++ b/drivers/mfd/mt6397-core.c >>>>>> @@ -270,22 +270,36 @@ static int mt6397_probe(struct platform_device *pdev) >>>>>> goto fail_irq; >>>>>> } >>>>>> >>>>>> + pmic->irq = platform_get_irq(pdev, 0); >>>>>> + >>>>>> switch (id & 0xff) { >>>>>> case MT6323_CID_CODE: >>>>>> - pmic->int_con[0] = MT6323_INT_CON0; >>>>>> - pmic->int_con[1] = MT6323_INT_CON1; >>>>>> - pmic->int_status[0] = MT6323_INT_STATUS0; >>>>>> - pmic->int_status[1] = MT6323_INT_STATUS1; >>>>>> + if (pmic->irq > 0) { >>>>> >>>>> should this not be >>>>> >>>>> if (pmic->irq >= 0) { >>>>> >>>>> i think the code before your patch was wrong as linux irqs start with 0. >>>>> >>>>> John >>>> Hi John, >>>> >>>> Thanks, I will modify this. >>> >>> Linux irq start from 1, 0 is invalid. I can't find the document saying >>> this now, but you could see this from irq_create_mapping() in >>> kernel/irq/irqdomain.c >>> >>> I think the code should have check return from platform_get_irq and >>> handle -EPROBE_DEFER, but maybe it should be another patch? >>> >>> BTW, in this function, it is possible that pmic->irq_domain will be NULL >>> in fail_irq error handling. We should check before calling >>> irq_domain_remove. >>> >>> Joe.C >>> >> >> Hi, >> >> looking at >> http://lxr.free-electrons.com/source/drivers/base/platform.c#L87 there >> is a check in line #100 ret >= 0 >> >> checking the return value of pmic->irq = platform_get_irq(pdev, 0); >> should follow the same pattern i think .. unless i have a thinko and am >> reading the code wrong. > > > I'm not sure why platform_get_irq() check for 0, but I think the code > logic is differnet. > > When platform_get_irq() return 0 to our code, it means we don't have > valid irq to use. In this case it doesn't make any sense to continue > init irq. > > > Joe.C > --> http://lwn.net/Articles/470820/ indeed ARM has changed this is seems. was not aware of this change, sorry for the noise John