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 88E71C43217 for ; Thu, 13 Jan 2022 23:07:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238188AbiAMXHb (ORCPT ); Thu, 13 Jan 2022 18:07:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40810 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238187AbiAMXH1 (ORCPT ); Thu, 13 Jan 2022 18:07:27 -0500 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8C7EEC06173F for ; Thu, 13 Jan 2022 15:07:27 -0800 (PST) Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1n89An-0001YX-LN; Fri, 14 Jan 2022 00:06:25 +0100 Received: from [2a0a:edc0:0:900:1d::77] (helo=ptz.office.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1n89Ai-00A99J-Gv; Fri, 14 Jan 2022 00:06:19 +0100 Received: from ukl by ptz.office.stw.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1n89Ah-0001rZ-FS; Fri, 14 Jan 2022 00:06:19 +0100 Date: Fri, 14 Jan 2022 00:06:19 +0100 From: Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= To: Florian Fainelli Cc: Mark Brown , Andrew Lunn , Ulf Hansson , Vignesh Raghavendra , KVM list , "Rafael J. Wysocki" , linux-iio@vger.kernel.org, Linus Walleij , Amit Kucheria , ALSA Development Mailing List , Jaroslav Kysela , Guenter Roeck , Thierry Reding , MTD Maling List , Linux I2C , "open list:GPIO SUBSYSTEM" , Miquel Raynal , linux-phy@lists.infradead.org, netdev@vger.kernel.org, linux-spi , Jiri Slaby , Khuong Dinh , Matthias Schiffer , Kamal Dasu , Lee Jones , Bartosz Golaszewski , Daniel Lezcano , Kishon Vijay Abraham I , Geert Uytterhoeven , "open list:SERIAL DRIVERS" , bcm-kernel-feedback-list , Zhang Rui , platform-driver-x86@vger.kernel.org, Linux PWM List , Robert Richter , Saravanan Sekar , Corey Minyard , Linux PM list , Liam Girdwood , Mauro Carvalho Chehab , John Garry , Takashi Iwai , Peter Korsgaard , William Breathitt Gray , Mark Gross , Hans de Goede , Alex Williamson , Sergey Shtylyov , Borislav Petkov , Jakub Kicinski , Matthias Brugger , openipmi-developer@lists.sourceforge.net, Andy Shevchenko , Benson Leung , Pengutronix Kernel Team , Linux ARM , linux-edac@vger.kernel.org, Tony Luck , Richard Weinberger , Mun Yew Tham , Eric Auger , Greg Kroah-Hartman , Yoshihiro Shimoda , Cornelia Huck , Linux MMC List , Joakim Zhang , Linux Kernel Mailing List , Linux-Renesas , Vinod Koul , James Morse , Zha Qipeng , Sebastian Reichel , Niklas =?utf-8?Q?S=C3=B6derlund?= , linux-mediatek@lists.infradead.org, Brian Norris , "David S. Miller" Subject: Re: [PATCH] driver core: platform: Rename platform_get_irq_optional() to platform_get_irq_silent() Message-ID: <20220113230619.m736tqd6u44vhuu5@pengutronix.de> References: <20220112085009.dbasceh3obfok5dc@pengutronix.de> <20220112213121.5ruae5mxwj6t3qiy@pengutronix.de> <20220113110831.wvwbm75hbfysbn2d@pengutronix.de> <20220113194358.xnnbhsoyetihterb@pengutronix.de> <745c601f-c782-0904-f786-c9bfced8f11c@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="ea4rbv6vfrsr5m67" Content-Disposition: inline In-Reply-To: <745c601f-c782-0904-f786-c9bfced8f11c@gmail.com> X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --ea4rbv6vfrsr5m67 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jan 13, 2022 at 01:42:57PM -0800, Florian Fainelli wrote: >=20 >=20 > On 1/13/2022 11:43 AM, Uwe Kleine-K=F6nig wrote: > > The subsystems regulator, clk and gpio have the concept of a dummy > > resource. For regulator, clk and gpio there is a semantic difference > > between the regular _get() function and the _get_optional() variant. > > (One might return the dummy resource, the other won't. Unfortunately > > which one implements which isn't the same for these three.) The > > difference between platform_get_irq() and platform_get_irq_optional() is > > only that the former might emit an error message and the later won't. > >=20 > > To prevent people's expectations that there is a semantic difference > > between these too, rename platform_get_irq_optional() to > > platform_get_irq_silent() to make the actual difference more obvious. > >=20 > > The #define for the old name can and should be removed once all patches > > currently in flux still relying on platform_get_irq_optional() are > > fixed. > >=20 > > Signed-off-by: Uwe Kleine-K=F6nig > > --- > > Hello, > >=20 > > On Thu, Jan 13, 2022 at 02:45:30PM +0000, Mark Brown wrote: > > > On Thu, Jan 13, 2022 at 12:08:31PM +0100, Uwe Kleine-K=F6nig wrote: > > >=20 > > > > This is all very unfortunate. In my eyes b) is the most sensible > > > > sense, but the past showed that we don't agree here. (The most anno= ying > > > > part of regulator_get is the warning that is emitted that regularily > > > > makes customers ask what happens here and if this is fixable.) > > >=20 > > > Fortunately it can be fixed, and it's safer to clearly specify things. > > > The prints are there because when the description is wrong enough to > > > cause things to blow up we can fail to boot or run messily and > > > forgetting to describe some supplies (or typoing so they haven't done > > > that) and people were having a hard time figuring out what might've > > > happened. > >=20 > > Yes, that's right. I sent a patch for such a warning in 2019 and pinged > > occationally. Still waiting for it to be merged :-\ > > (https://lore.kernel.org/r/20190625100412.11815-1-u.kleine-koenig@pengu= tronix.de) > >=20 > > > > I think at least c) is easy to resolve because > > > > platform_get_irq_optional() isn't that old yet and mechanically > > > > replacing it by platform_get_irq_silent() should be easy and safe. > > > > And this is orthogonal to the discussion if -ENOXIO is a sensible r= eturn > > > > value and if it's as easy as it could be to work with errors on irq > > > > lookups. > > >=20 > > > It'd certainly be good to name anything that doesn't correspond to one > > > of the existing semantics for the API (!) something different rather > > > than adding yet another potentially overloaded meaning. > >=20 > > It seems we're (at least) three who agree about this. Here is a patch > > fixing the name. >=20 > From an API naming perspective this does not make much sense anymore with > the name chosen, it is understood that whent he function is called > platform_get_irq_optional(), optional applies to the IRQ. An optional IRQ= is > something people can reason about because it makes sense. The problem I see is that the semantic is different to the other available *_get_optional() functions. And this isn't fixable for irqs. So better don't use that naming scheme. > What is a a "silent" IRQ however? It does not apply to the object it is > trying to fetch to anymore, but to the message that may not be printed in > case the resource failed to be obtained, because said resource is optiona= l. > Woah, that's quite a stretch. I'm surprised that the semantic isn't obvious, but ok, I can accept that.Can you maek a constructive suggestion here? What name pair would you choose for the two functions functions under discussion? (BTW, my favourite would be that platform_get_irq() doesn't emit an error message and the caller is reliable for emitting that. But I think it's too late for this approach.) > Following the discussion and original 2 patches set from Sergey, it is not > entirely clear to me anymore what is it that we are trying to fix. (I think) Sergey's focus is: platform_get_irq_optional() returning -ENXIO is ugly, other functions return -ENOENT and other *_get_optional() functions return NULL for "This resource doesn't exist". So let's return 0 in this case. My focus is: There cannot be an "optional irq" where the driver doesn't have to care if the irq actually exist or not. So the pattern with *_get_optional() isn't sensible for irqs and if changing the returned value meaning "This resource doesn't exist" is sensible for platform_get_irq_optional(), I claim it's sensible for platform_get_irq(), too. So the semantic difference between platform_get_irq() and platform_get_irq_optional() is only that one emits an error message and the other doesn't. So this function pair should use a different naming than get + get_optional as this naming evokes expectations that must be wrong as there cannot be a dummy irq value. > I nearly forgot, I would paint it blue, sky blue, not navy blue, not light > blue ;) no way. green is the ultimate blue for platform_get_irq() :-) Best regards Uwe --=20 Pengutronix e.K. | Uwe Kleine-K=F6nig | Industrial Linux Solutions | https://www.pengutronix.de/ | --ea4rbv6vfrsr5m67 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEfnIqFpAYrP8+dKQLwfwUeK3K7AkFAmHgsGcACgkQwfwUeK3K 7AmCGgf+KUjAbnx/+md2hoJgWXkf2TARYfElER6NhM1xxoNKhleR2n9Y2SomZoh7 GcsuunNU5jXbVHMH53qA3p34MwFiUjtH8qugReIosuYo9kAjJHcR/uAXVZVx8a5W 593KJ+wnpGGjBIajlW4L9XKhKUGIgCjx5n9pZTnS/9TD0T5RY7pvpN1XdyHhqHzO owFdQFBvf7vN9Md4mdzl3usr15hf3ZFkobzBuDjMwour/CoOVu6yOVe+ihkXfa4o SQua8+L+ooV6dgRrG0kq9oYU/xDTMEPJCK1Ap8ff2rb9KDCaRwljavHmmk6Thff9 7uYWNCwmj3gTXd6TD4b3BK+FIBMfSQ== =oNtc -----END PGP SIGNATURE----- --ea4rbv6vfrsr5m67--