From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A94C7C433F5 for ; Wed, 12 Jan 2022 12:30:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=/dc/5Te1JOtbfpJgJCUX8uGJQ/jzEkxcIUxdbzzln7U=; b=ZuDpX3QacYklFw jjTIp7s6S1DNwZEiHoy0vq2KqfMnY3VlAXHLG7PtGtxOQh0EAeQto+bIPHwkatIRajX1/1bU+On98 3w7jhsmHjmCM8Dx/gFOU/5/FAFi2PMSpdhy9EOyk4Hyl7f2mn8NXbrokHb0AJMRCapmpuJjhQzYie k3GdJksIsWEQitJloYnB/RaRpXrh7HenPZws9OwA0UyQj4kbiM0R0tjAiV4TDMCgIdawUBkbxjDqE s2QPlGKUyKw4wqeiF1UEiIFd+Giavlp6Br11eSoZHBOi6k3er4PAIcqrz6bCqRcRteTwENLRkngi3 hQnbCZNTFw/Ku0vcXI9Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1n7cl0-002UHH-R9; Wed, 12 Jan 2022 12:29:38 +0000 Received: from mga06.intel.com ([134.134.136.31]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1n7ckw-002UGQ-72; Wed, 12 Jan 2022 12:29:35 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1641990574; x=1673526574; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=7u2c/+u/7900R51hbSn1pNSHHzU5y3Q///2YVkNposY=; b=j3c7xL3T2Cx1Zsd+ppfFG6/CLjSSvIJEAw4QTVLA6tB2AraYJYhd2MhQ ZzwteHKVxIL0j09G0CGrLjs+Yro29FNWzMSWriqRlEDzj0tuAV+6MAFce FxTZzPfLKL4DYBDV/MG/fFU2d3uqphYsKxOsBZpYCZm676LIkOEOk1zA9 GHKd9J8xpYg0QAEoK5ZNSMQlG6vUCblq0FvaR7feDvp7FDMvq+JraGwJw W9CyF2x/uvu0S31lIiDY42CwPpi3G+glyavjQR2Zi03QCWHNKWIQ/lEsp eSrSqKHqfOgdBq6Q9asQ14gg6ZzaY/nwB0wugaZ2F5mzvSs3JUVVIJWL4 Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10224"; a="304460712" X-IronPort-AV: E=Sophos;i="5.88,282,1635231600"; d="scan'208";a="304460712" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jan 2022 04:29:31 -0800 X-IronPort-AV: E=Sophos;i="5.88,282,1635231600"; d="scan'208";a="691367097" Received: from smile.fi.intel.com ([10.237.72.61]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jan 2022 04:29:15 -0800 Received: from andy by smile.fi.intel.com with local (Exim 4.95) (envelope-from ) id 1n7cjO-009gDi-VM; Wed, 12 Jan 2022 14:27:58 +0200 Date: Wed, 12 Jan 2022 14:27:58 +0200 From: Andy Shevchenko To: Geert Uytterhoeven Cc: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , Andrew Lunn , Ulf Hansson , Vignesh Raghavendra , KVM list , "Rafael J. Wysocki" , linux-iio@vger.kernel.org, Linus Walleij , Amit Kucheria , ALSA Development Mailing List , Liam Girdwood , Guenter Roeck , Thierry Reding , MTD Maling List , Linux I2C , Miquel Raynal , linux-phy@lists.infradead.org, Jiri Slaby , "David S. Miller" , Khuong Dinh , Florian Fainelli , Matthias Schiffer , Joakim Zhang , Kamal Dasu , Lee Jones , Bartosz Golaszewski , Daniel Lezcano , Tony Luck , Kishon Vijay Abraham I , bcm-kernel-feedback-list , "open list:SERIAL DRIVERS" , Jakub Kicinski , Zhang Rui , Matthias Brugger , platform-driver-x86@vger.kernel.org, Linux PWM List , Robert Richter , Saravanan Sekar , Corey Minyard , Linux PM list , Mauro Carvalho Chehab , John Garry , Peter Korsgaard , William Breathitt Gray , Mark Gross , "open list:GPIO SUBSYSTEM" , Alex Williamson , Mark Brown , Borislav Petkov , Eric Auger , Takashi Iwai , Jaroslav Kysela , openipmi-developer@lists.sourceforge.net, Benson Leung , Pengutronix Kernel Team , Linux ARM , linux-edac@vger.kernel.org, Sergey Shtylyov , Richard Weinberger , Mun Yew Tham , Hans de Goede , Greg Kroah-Hartman , Yoshihiro Shimoda , Cornelia Huck , Linux MMC List , Linux Kernel Mailing List , linux-spi , Linux-Renesas , Vinod Koul , James Morse , Zha Qipeng , Sebastian Reichel , Niklas =?iso-8859-1?Q?S=F6derlund?= , linux-mediatek@lists.infradead.org, Brian Norris , netdev@vger.kernel.org Subject: Re: [PATCH 1/2] platform: make platform_get_irq_optional() optional Message-ID: References: <20220110195449.12448-1-s.shtylyov@omp.ru> <20220110195449.12448-2-s.shtylyov@omp.ru> <20220110201014.mtajyrfcfznfhyqm@pengutronix.de> <20220112085009.dbasceh3obfok5dc@pengutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220112_042934_351989_812E4B1A X-CRM114-Status: GOOD ( 39.13 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org On Wed, Jan 12, 2022 at 11:27:02AM +0100, Geert Uytterhoeven wrote: > On Wed, Jan 12, 2022 at 9:51 AM Uwe Kleine-K=F6nig > wrote: > > On Wed, Jan 12, 2022 at 09:33:48AM +0100, Geert Uytterhoeven wrote: > > > On Mon, Jan 10, 2022 at 10:20 PM Andrew Lunn wrote: > > > > On Mon, Jan 10, 2022 at 09:10:14PM +0100, Uwe Kleine-K=F6nig wrote: > > > > > On Mon, Jan 10, 2022 at 10:54:48PM +0300, Sergey Shtylyov wrote: > > > > > > This patch is based on the former Andy Shevchenko's patch: > > > > > > > > > > > > https://lore.kernel.org/lkml/20210331144526.19439-1-andriy.shev= chenko@linux.intel.com/ > > > > > > > > > > > > Currently platform_get_irq_optional() returns an error code eve= n if IRQ > > > > > > resource simply has not been found. It prevents the callers fro= m being > > > > > > error code agnostic in their error handling: > > > > > > > > > > > > ret =3D platform_get_irq_optional(...); > > > > > > if (ret < 0 && ret !=3D -ENXIO) > > > > > > return ret; // respect deferred probe > > > > > > if (ret > 0) > > > > > > ...we get an IRQ... > > > > > > > > > > > > All other *_optional() APIs seem to return 0 or NULL in case an= optional > > > > > > resource is not available. Let's follow this good example, so t= hat the > > > > > > callers would look like: > > > > > > > > > > > > ret =3D platform_get_irq_optional(...); > > > > > > if (ret < 0) > > > > > > return ret; > > > > > > if (ret > 0) > > > > > > ...we get an IRQ... > > > > > > > > > > The difference to gpiod_get_optional (and most other *_optional) = is that > > > > > you can use the NULL value as if it were a valid GPIO. > > > > > > > > > > As this isn't given with for irqs, I don't think changing the ret= urn > > > > > value has much sense. > > > > > > > > We actually want platform_get_irq_optional() to look different to a= ll > > > > the other _optional() methods because it is not equivalent. If it > > > > looks the same, developers will assume it is the same, and get > > > > themselves into trouble. > > > > > > Developers already assume it is the same, and thus forget they have > > > to check against -ENXIO instead of zero. > > > > Is this an ack for renaming platform_get_irq_optional() to > > platform_get_irq_silent()? > = > No it isn't ;-) > = > If an optional IRQ is not present, drivers either just ignore it (e.g. > for devices that can have multiple interrupts or a single muxed IRQ), > or they have to resort to polling. For the latter, fall-back handling > is needed elsewhere in the driver. > To me it sounds much more logical for the driver to check if an > optional irq is non-zero (available) or zero (not available), than to > sprinkle around checks for -ENXIO. In addition, you have to remember > that this one returns -ENXIO, while other APIs use -ENOENT or -ENOSYS > (or some other error code) to indicate absence. I thought not having > to care about the actual error code was the main reason behind the > introduction of the *_optional() APIs. For the record, I'm on the same page with Geert. -- = With Best Regards, Andy Shevchenko ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/