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_HELO_NONE,SPF_PASS autolearn=no 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 AC857C432C3 for ; Tue, 3 Dec 2019 08:18:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8DAA02064B for ; Tue, 3 Dec 2019 08:18:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726190AbfLCISL (ORCPT ); Tue, 3 Dec 2019 03:18:11 -0500 Received: from mail-ot1-f67.google.com ([209.85.210.67]:39478 "EHLO mail-ot1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725845AbfLCISK (ORCPT ); Tue, 3 Dec 2019 03:18:10 -0500 Received: by mail-ot1-f67.google.com with SMTP id 77so2148995oty.6; Tue, 03 Dec 2019 00:18:10 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=gBtOE1GdWf2jzATlRbrF8r8Pac6d5nQ4OzH7cwGAR94=; b=b+m13b3CkvQfHjFMmIRLCWHuM3weg+qEBDCakTYL5msGW+URm18UNn563N0Kqw0ut0 xP+lH3/HGq2BMU+spjBBYcC9Cb+78tpW7yy3ySLggmRmVByCMwTFY/4Ucgo7Akiw1A75 mKq37EDgN3klAjpfcS9hSaEsn9XhutvYasivZbdaNzFibSZb9eIiq/vjmdYT4bGqye72 69xqvTZx6uZbXcVaAdCu+pl7J5bICfLM9oM9eT7tn7grjfm7cRGDm/txW5VVZiZgdymC 7cmXLlpLlGXahovpcl0/xVYTkBbjErfggae43lJxfDghOHpRjJJGJmo0ixWOGHuKJ+vc ZRPQ== X-Gm-Message-State: APjAAAVRpMyApozG4Ibe0l5j8+hA7Rzmk6Tvm+WtGxmLkU6Kbl8uBdd3 jMSNYPA4mZ0hGvW5CIcvZwYnulIG/ppA1P/HhL8= X-Google-Smtp-Source: APXvYqzBuvWMWrwsEDDhZ2tcNfeX7um84g4QQ5ld7WP0VV8LQtkLVFpjZhnV4oe+jaJ4tYQpo65700XzoJh4+uCOqZU= X-Received: by 2002:a9d:3a37:: with SMTP id j52mr2353717otc.39.1575361089532; Tue, 03 Dec 2019 00:18:09 -0800 (PST) MIME-Version: 1.0 References: <20191127084253.16356-1-geert+renesas@glider.be> <20191127084253.16356-6-geert+renesas@glider.be> <585c4ad9-31fc-e87e-07c4-b8d6aa09c7e4@mentor.com> In-Reply-To: <585c4ad9-31fc-e87e-07c4-b8d6aa09c7e4@mentor.com> From: Geert Uytterhoeven Date: Tue, 3 Dec 2019 09:17:58 +0100 Message-ID: Subject: Re: [PATCH v3 5/7] gpio: Add GPIO Aggregator/Repeater driver To: Harish Jenny K N Cc: Geert Uytterhoeven , Linus Walleij , Bartosz Golaszewski , Jonathan Corbet , Rob Herring , Mark Rutland , Eugeniu Rosca , Alexander Graf , Peter Maydell , Paolo Bonzini , Phil Reid , Marc Zyngier , Christoffer Dall , Magnus Damm , "open list:GPIO SUBSYSTEM" , "open list:DOCUMENTATION" , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Linux-Renesas , Linux Kernel Mailing List , QEMU Developers Content-Type: text/plain; charset="UTF-8" Sender: linux-renesas-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@vger.kernel.org Hi Harish, On Tue, Dec 3, 2019 at 6:42 AM Harish Jenny K N wrote: > > +static int gpio_aggregator_probe(struct platform_device *pdev) > > +{ > > + struct device *dev = &pdev->dev; > > + struct gpio_desc **descs; > > + struct gpiochip_fwd *fwd; > > + int i, n; > > + > > + n = gpiod_count(dev, NULL); > > + if (n < 0) > > + return n; > > + > > + descs = devm_kmalloc_array(dev, n, sizeof(*descs), GFP_KERNEL); > > + if (!descs) > > + return -ENOMEM; > > + > > + for (i = 0; i < n; i++) { > > + descs[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS); > > can you please add this check as well as we need to return EPROBE_DEFER. > > if (desc[i] == ERR_PTR(-ENOENT)) > < return -EPROBE_DEFER; So gpiod_get_index() nevers return -EPROBE_DEFER, but returns -ENOENT instead? How can a driver distinguish between "GPIO not found" and "gpiochip driver not yet initialized"? Worse, so the *_optional() variants will return NULL in both cases, too, so the caller will always fall back to optional GPIO not present? Or am I missing something? Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds