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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 87572C34022 for ; Mon, 17 Feb 2020 19:07:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6DA082070B for ; Mon, 17 Feb 2020 19:07:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729242AbgBQTHv (ORCPT ); Mon, 17 Feb 2020 14:07:51 -0500 Received: from eddie.linux-mips.org ([148.251.95.138]:57570 "EHLO cvs.linux-mips.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728054AbgBQTHv (ORCPT ); Mon, 17 Feb 2020 14:07:51 -0500 Received: (from localhost user: 'ladis' uid#1021 fake: STDIN (ladis@eddie.linux-mips.org)) by eddie.linux-mips.org id S23990923AbgBQTHr3cfaD (ORCPT + 1 other); Mon, 17 Feb 2020 20:07:47 +0100 Date: Mon, 17 Feb 2020 20:07:45 +0100 From: Ladislav Michl To: "H. Nikolaus Schaller" Cc: MyungJoo Ham , Chanwoo Choi , linux-kernel@vger.kernel.org, letux-kernel@openphoenux.org, kernel@pyra-handheld.com, linux-omap@vger.kernel.org Subject: Re: [PATCH v3] extcon: palmas: hide error messages if gpio returns -EPROBE_DEFER Message-ID: <20200217190745.GA147152@lenoch> References: <20200217182906.GA140676@lenoch> <012228CC-2B49-4AAE-B574-92E44621F0D6@goldelico.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <012228CC-2B49-4AAE-B574-92E44621F0D6@goldelico.com> Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org On Mon, Feb 17, 2020 at 07:38:16PM +0100, H. Nikolaus Schaller wrote: > Hi, > > > Am 17.02.2020 um 19:29 schrieb Ladislav Michl : > > > > On Mon, Feb 17, 2020 at 02:58:14PM +0100, H. Nikolaus Schaller wrote: > >> > >>> Am 17.02.2020 um 14:38 schrieb H. Nikolaus Schaller : > >>> > >>> If the gpios are probed after this driver (e.g. if they > >>> come from an i2c expander) there is no need to print an > >>> error message. > >>> > >>> Signed-off-by: H. Nikolaus Schaller > >>> --- > >>> drivers/extcon/extcon-palmas.c | 8 ++++++-- > >>> 1 file changed, 6 insertions(+), 2 deletions(-) > >>> > >>> diff --git a/drivers/extcon/extcon-palmas.c b/drivers/extcon/extcon-palmas.c > >>> index edc5016f46f1..cea58d0cb457 100644 > >>> --- a/drivers/extcon/extcon-palmas.c > >>> +++ b/drivers/extcon/extcon-palmas.c > >>> @@ -205,14 +205,18 @@ static int palmas_usb_probe(struct platform_device *pdev) > >>> > >>> palmas_usb->id_gpiod = devm_gpiod_get_optional(&pdev->dev, "id", > >>> GPIOD_IN); > >>> - if (IS_ERR(palmas_usb->id_gpiod)) { > >>> + if (PTR_ERR(palmas_usb->id_gpiod) == -EPROBE_DEFER) { > >>> + return -EPROBE_DEFER; > >>> + } else if (IS_ERR(palmas_usb->id_gpiod)) { > >> > >> Hm. > >> > >> While looking again at that: why do we need the "{" and "} else "? > >> > >> It should be sufficient to have > >> > >>> palmas_usb->id_gpiod = devm_gpiod_get_optional(&pdev->dev, "id", > >>> GPIOD_IN); > >>> + if (PTR_ERR(palmas_usb->id_gpiod) == -EPROBE_DEFER) > >>> + return -EPROBE_DEFER; > >>> if (IS_ERR(palmas_usb->id_gpiod)) { > >> > >> What do you think is better coding style here? > > > > How about something like this? (just an idea with some work left for you ;-)) > > > > --- a/drivers/extcon/extcon-palmas.c > > +++ b/drivers/extcon/extcon-palmas.c > > @@ -206,8 +206,10 @@ static int palmas_usb_probe(struct platform_device *pdev) > > palmas_usb->id_gpiod = devm_gpiod_get_optional(&pdev->dev, "id", > > GPIOD_IN); > > if (IS_ERR(palmas_usb->id_gpiod)) { > > - dev_err(&pdev->dev, "failed to get id gpio\n"); > > - return PTR_ERR(palmas_usb->id_gpiod); > > + status = PTR_ERR(palmas_usb->id_gpiod); > > + if (status != -EPROBE_DEFER) > > + dev_err(&pdev->dev, "failed to get id gpio: %d\n", status); > > + return status; > > } > > Well, what would be the improvement? Linux kernel prints so many lines on bootup and only few of them are valuable. Lets improve it by printing error value to give a clue why it failed. > It needs an additional variable and makes the change more complex. That additional variable is already there... > The main suggestion by Chanwoo Choi was to move the check for EPROBE_DEFER > outside of the IS_ERR() because checking this first and then for EPROBE_DEFER > is not necessary. True, but there are two checks either way and this is slow path. > If acceptable I'd prefer my last proposal. It just adds 2 LOC before > and without touching the existing if (IS_ERR(...)). I have no strong opinion. I was just waiting for project to compile so, consider my reply as product of boredom :) (However, I do not like "let's touch only minimal number of lines" argument. End result should still matter more) > If the compiler is clever it can cache palmas_usb->id_gpiod in a register > which serves the same purpose as the status variable. I'm not trying to outsmart compiler, but note status variable is needed three times. > > > > palmas_usb->vbus_gpiod = devm_gpiod_get_optional(&pdev->dev, "vbus", > > BR and thanks, > Nikolaus