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 alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (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 1063EC433F5 for ; Wed, 12 Jan 2022 16:48:17 +0000 (UTC) Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id 4D2A21B5B; Wed, 12 Jan 2022 17:47:25 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 4D2A21B5B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1642006095; bh=7u2c/+u/7900R51hbSn1pNSHHzU5y3Q///2YVkNposY=; h=Date:From:To:Subject:References:In-Reply-To:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=kHVgHwYl7t6D5l8g4Kmt57jYUNCW6Wp8fiJTWaqong5al5UkgX64difQvuNDE1a7z chs/7j+OnBzOdKLUyL82O3t4IVLmdXMsYDZREg4lalV+qKKJgtb1Wfl3qK030sc8qO roFwgvD1udbhaH1kmBO4qVPMdISF0JCRqvYgBB0U= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id 58467F80526; Wed, 12 Jan 2022 17:45:10 +0100 (CET) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 1E728F8026A; Wed, 12 Jan 2022 13:29:45 +0100 (CET) Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 14FC9F80236 for ; Wed, 12 Jan 2022 13:29:35 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 14FC9F80236 Authentication-Results: alsa1.perex.cz; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="EqQPvgGm" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1641990579; x=1673526579; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=7u2c/+u/7900R51hbSn1pNSHHzU5y3Q///2YVkNposY=; b=EqQPvgGmP9NyFP0CQSx/zoygbF+vWi5c7Ap0XWc6qhTJfhs/yz7sSwsA ZZtENjUQ8qBroHQtZsBlVs2BdPl7VaNpiubJq/Z7FNv5sfsoEE546QF64 ySaUqZeSTOIHf8hzcq+aeu+q5K0SwyXQYCybflJCGfY69rvXWFs5saDvh z2JSP6Q4KwAvKJ6wdjqmdhiwo1Ur+6cZ/kBSb7eJEZQp8PieWfOojiccY To+pQ8/ka/Gdy+IYo5LeTHK1QMGDAM118YtII8MRl2ovC+3iJj3rubVN6 Hz860dfmwVwiA6hGEjgYLqFv+15MH1OmAuvXxqzKHeAoCuGxtWsd3didI Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10224"; a="330069223" X-IronPort-AV: E=Sophos;i="5.88,282,1635231600"; d="scan'208";a="330069223" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jan 2022 04:29:32 -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 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-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo X-Mailman-Approved-At: Wed, 12 Jan 2022 17:45:04 +0100 Cc: Andrew Lunn , Ulf Hansson , Vignesh Raghavendra , KVM list , "Rafael J. Wysocki" , linux-iio@vger.kernel.org, Linus Walleij , Amit Kucheria , ALSA Development Mailing List , Joakim Zhang , Guenter Roeck , Thierry Reding , MTD Maling List , Linux I2C , Miquel Raynal , linux-phy@lists.infradead.org, netdev@vger.kernel.org, linux-spi , Jiri Slaby , openipmi-developer@lists.sourceforge.net, Khuong Dinh , Florian Fainelli , Matthias Schiffer , Kamal Dasu , Lee Jones , Bartosz Golaszewski , Daniel Lezcano , Kishon Vijay Abraham I , bcm-kernel-feedback-list , "open list:SERIAL DRIVERS" , Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , Jakub Kicinski , Zhang Rui , Linux PWM List , Hans de Goede , 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 , Sebastian Reichel , Matthias Brugger , Takashi Iwai , platform-driver-x86@vger.kernel.org, Benson Leung , Linux ARM , linux-edac@vger.kernel.org, Tony Luck , Mun Yew Tham , Eric Auger , Greg Kroah-Hartman , Yoshihiro Shimoda , Cornelia Huck , Linux MMC List , Liam Girdwood , Linux Kernel Mailing List , Linux-Renesas , Sergey Shtylyov , Vinod Koul , James Morse , Zha Qipeng , Pengutronix Kernel Team , Richard Weinberger , Niklas =?iso-8859-1?Q?S=F6derlund?= , linux-mediatek@lists.infradead.org, Brian Norris , "David S. Miller" X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" On Wed, Jan 12, 2022 at 11:27:02AM +0100, Geert Uytterhoeven wrote: > On Wed, Jan 12, 2022 at 9:51 AM Uwe Kleine-König > 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-König 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.shevchenko@linux.intel.com/ > > > > > > > > > > > > Currently platform_get_irq_optional() returns an error code even if IRQ > > > > > > resource simply has not been found. It prevents the callers from being > > > > > > error code agnostic in their error handling: > > > > > > > > > > > > ret = platform_get_irq_optional(...); > > > > > > if (ret < 0 && ret != -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 that the > > > > > > callers would look like: > > > > > > > > > > > > ret = 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 return > > > > > value has much sense. > > > > > > > > We actually want platform_get_irq_optional() to look different to all > > > > 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 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 71B21C433F5 for ; Wed, 12 Jan 2022 12:29:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353137AbiALM3g (ORCPT ); Wed, 12 Jan 2022 07:29:36 -0500 Received: from mga14.intel.com ([192.55.52.115]:52070 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240498AbiALM3e (ORCPT ); Wed, 12 Jan 2022 07:29:34 -0500 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="243922983" X-IronPort-AV: E=Sophos;i="5.88,282,1635231600"; d="scan'208";a="243922983" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jan 2022 04:29:32 -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-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: linux-edac@vger.kernel.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-König > 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-König 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.shevchenko@linux.intel.com/ > > > > > > > > > > > > Currently platform_get_irq_optional() returns an error code even if IRQ > > > > > > resource simply has not been found. It prevents the callers from being > > > > > > error code agnostic in their error handling: > > > > > > > > > > > > ret = platform_get_irq_optional(...); > > > > > > if (ret < 0 && ret != -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 that the > > > > > > callers would look like: > > > > > > > > > > > > ret = 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 return > > > > > value has much sense. > > > > > > > > We actually want platform_get_irq_optional() to look different to all > > > > 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 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 631EAC4332F for ; Wed, 12 Jan 2022 12:29:49 +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=3KYP5zr2lNX4Ge4qA17i5vo7SCbjTr2QMgXxYufzgNE=; b=AVNrUTY6Rk2k6t FxxoaivarAmtr5Neh6XrIggZvmpxIT478nSBoT2nx7e5fjPp0M33ZwNLlMd0oY1F87eahyvoTPgZ8 mXIcMDxqEJqUJr2oIVzIjXIVVF5bvpVP1TpxbGPUd0gZeCT9bY6J1sK2LSVhcgFfybSbvYF2luyp7 HEvv82j+NJxObSBsPrgmzg3SWCvBeYKvZZ4Ot6wsxsoJsyFNV/Dcp//ZXPnaNHySUmI35Y3tODr+D JaqeAXDTCaMGPio0S1LP2WYsBC18fRJFh8MP2EiqjE613YGOoqS+4dMM29mkaGIXJa3pxpxwWPsFg z0JNan2xZUterDZAtF1w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1n7ckz-002UH9-Hj; Wed, 12 Jan 2022 12:29:37 +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-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: 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-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=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-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek 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/ 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 E3139C433EF for ; Wed, 12 Jan 2022 12:29:37 +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=C6neZByVAS/KMSmBPLYUoAxohpTzlFL/ctnAssl3wLY=; b=vvLzOIAp0sppGz blpmH3xLR5hq4OXN7xj+t4XxZaYDaf7vIP6n46jv63x+wkK52c5WPskBVIlGpQQkIoiwfIfQrlJsG y1cULtu8DQpHhOF4H6aUMDuXEKEkofx2/OjC3epslf65r5iXruXOqWOpwdVIyBT2mSwZI+7D4NVZx OFT9WqcKDrMI0bb9uIQDe6gwI2kwFZCldYnThLUmuHm6EK65VIFri0ou8KEapbJ4S8rXI5yckZJWb H+HN031AHTs1PCATXW/DaJQvsEWEYRQtW5nSHF7AfoxSgC7J7rsVKpWG/wzOA6e3oUHJpna7XwFSP Yv9w3OMcQNQxdS32O+QQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1n7ckz-002UH4-CF; Wed, 12 Jan 2022 12:29:37 +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-phy@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux Phy 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-phy" Errors-To: linux-phy-bounces+linux-phy=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-phy mailing list linux-phy@lists.infradead.org https://lists.infradead.org/mailman/listinfo/linux-phy