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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 8486DC6778A for ; Tue, 3 Jul 2018 17:31:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3471920834 for ; Tue, 3 Jul 2018 17:31:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3471920834 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bootlin.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934293AbeGCRbp (ORCPT ); Tue, 3 Jul 2018 13:31:45 -0400 Received: from mail.bootlin.com ([62.4.15.54]:47219 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933569AbeGCRbn (ORCPT ); Tue, 3 Jul 2018 13:31:43 -0400 Received: by mail.bootlin.com (Postfix, from userid 110) id 73F9A20737; Tue, 3 Jul 2018 19:31:41 +0200 (CEST) Received: from bbrezillon (91-160-177-164.subs.proxad.net [91.160.177.164]) by mail.bootlin.com (Postfix) with ESMTPSA id 41A852069C; Tue, 3 Jul 2018 19:31:41 +0200 (CEST) Date: Tue, 3 Jul 2018 19:31:41 +0200 From: Boris Brezillon To: Janusz Krzysztofik Cc: Linus Walleij , linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] gpiolib: Defer on non-DT find_chip_by_name() failure Message-ID: <20180703193141.747fa950@bbrezillon> In-Reply-To: <20180703172635.32508-1-jmkrzyszt@gmail.com> References: <20180703172635.32508-1-jmkrzyszt@gmail.com> X-Mailer: Claws Mail 3.15.0-dirty (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Janusz, On Tue, 3 Jul 2018 19:26:35 +0200 Janusz Krzysztofik wrote: > Avoid replication of error code conversion in non-DT GPIO consumers' > code by returning -EPROBE_DEFER from gpiod_find() in case a chip > identified by its label in a registered lookup table is not ready. > > See https://lkml.org/lkml/2018/5/30/176 for example case. > > Signed-off-by: Janusz Krzysztofik > --- > If accepted, please add > Suggested-by: Boris Brezillon > if Boris doesn't mind. > > Thanks, > Janusz > > drivers/gpio/gpiolib.c | 13 ++++++++++--- > 1 file changed, 10 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c > index e11a3bb03820..15dc77c80328 100644 > --- a/drivers/gpio/gpiolib.c > +++ b/drivers/gpio/gpiolib.c > @@ -3639,9 +3639,16 @@ static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id, > chip = find_chip_by_name(p->chip_label); > > if (!chip) { > - dev_err(dev, "cannot find GPIO chip %s\n", > - p->chip_label); > - return ERR_PTR(-ENODEV); > + /* > + * As the lookup table indicates a chip with > + * p->chip_label should exist, assume it may > + * still appear latar and let the interested ^ later > + * consumer be probed again or let the Deferred > + * Probe infrastructure handle the error. > + */ > + dev_warn(dev, "cannot find GPIO chip %s, deferring\n", > + p->chip_label); > + return ERR_PTR(-EPROBE_DEFER); > } > > if (chip->ngpio <= p->chip_hwnum) { Looks good otherwise. Let's hope we're not breaking implementations testing for -ENODEV... Reviewed-by: Boris Brezillon Regards, Boris