Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752906AbdLFG3X (ORCPT ); Wed, 6 Dec 2017 01:29:23 -0500 Received: from mail-io0-f195.google.com ([209.85.223.195]:45397 "EHLO mail-io0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752638AbdLFG3W (ORCPT ); Wed, 6 Dec 2017 01:29:22 -0500 X-Google-Smtp-Source: AGs4zMZQc4YUEWuk/bHE2ii2NvZAHsYtQ1/CKtSfZQaNKgKqcjqMCSOcJ4wENVeHeEon2yADcVGUjw== Subject: Re: [PATCH] driver-core: platform: Avoid to return IRQ 0 in platform_get_irq() To: Dmitry Torokhov References: <20171205182003.oto6qnus3e3vy64f@dtor-ws> Cc: gregkh@linuxfoundation.org, davem@davemloft.net, linus.walleij@linaro.org, linux-kernel@vger.kernel.org From: Arvind Yadav Message-ID: <624b5f73-49e2-5eaa-63bd-b04edb4654b0@gmail.com> Date: Wed, 6 Dec 2017 11:58:53 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <20171205182003.oto6qnus3e3vy64f@dtor-ws> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1770 Lines: 54 Hi Dmitry, On Tuesday 05 December 2017 11:50 PM, Dmitry Torokhov wrote: > On Tue, Dec 05, 2017 at 11:41:52PM +0530, Arvind Yadav wrote: >> Function platform_get_irq() can return 0. Which means NO_IRQ. >> So this change will not allow to return 0. >> >> This change is help to use platform_get_irq() without this, >> >> val = platform_get_irq(); >> if (val <= 0) >> ret = val ? val : -ENODEV; >> >> Signed-off-by: Arvind Yadav > You need to audit the drivers and make sure you are not breaking them > with this. I believe at least i2c designware controller on certain > boards has DEFINE_RES_IRQ(0) which will be broken by this patch. Yes, you are right. Few driver is using DEFINE_RES_IRQ(0). Example: drivers/mfd/intel-lpss.c static const struct resource intel_lpss_dev_resources[] = { DEFINE_RES_MEM_NAMED(LPSS_DEV_OFFSET, LPSS_DEV_SIZE, "lpss_dev"), DEFINE_RES_MEM_NAMED(LPSS_PRIV_OFFSET, LPSS_PRIV_SIZE, "lpss_priv"), DEFINE_RES_IRQ(0), }; There's a bunch of platforms in the kernel that still use IRQ0. They can suffer because of this change. I should have mark this patch for testing. > >> --- >> drivers/base/platform.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/base/platform.c b/drivers/base/platform.c >> index c203fb9..7b3079c 100644 >> --- a/drivers/base/platform.c >> +++ b/drivers/base/platform.c >> @@ -127,7 +127,7 @@ int platform_get_irq(struct platform_device *dev, unsigned int num) >> irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS); >> } >> >> - return r ? r->start : -ENXIO; >> + return r && r->start ? r->start : -ENXIO; >> #endif >> } >> EXPORT_SYMBOL_GPL(platform_get_irq); >> -- >> 2.7.4 >> > Thanks. > Thanks,