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 D575AECDFBB for ; Wed, 18 Jul 2018 13:19:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 84CF82075A for ; Wed, 18 Jul 2018 13:19:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 84CF82075A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-m68k.org 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 S1731045AbeGRN52 (ORCPT ); Wed, 18 Jul 2018 09:57:28 -0400 Received: from mail-vk0-f67.google.com ([209.85.213.67]:37862 "EHLO mail-vk0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729324AbeGRN51 (ORCPT ); Wed, 18 Jul 2018 09:57:27 -0400 Received: by mail-vk0-f67.google.com with SMTP id h22-v6so2468594vke.4; Wed, 18 Jul 2018 06:19:34 -0700 (PDT) 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=kYoOIVg64PcNaaNfF3yyFYLBV1F4MsA0goiY2vfv6Oc=; b=to61RU+tUXliltFPumXL0ACjrHdvXZgSdnJNltjcynTjjOAGmPdUL+9TlfFJQ+1FwN gG9eBbZajyLjYPjbU+P4NKzGt0IfOO285V3xl7oiqv9tzmDlSf8ciZ/HxRmzHaBlMnGj Se2hmZ00F0QaiF5uKsAFiEEYCFSSDsX/QiZFwvphOxfUsCchJy9Cq/aHPRsS/PHqdDO/ cYo+dDGBKzkUelOiFyZGJAe7eGeZIImd2PYVCTVfilixSRabOx7qXEBF0zWWO3SDoGoU BqEURawCYOrDasMHqvN/7Xkjvwvqy2mG1eQLsAQD2GoG0/hlnn6u7bjbsMag7myOcqIQ iaow== X-Gm-Message-State: AOUpUlGrR6kx7OVubTrbaHeNCZbGF/yahTqZjM5JOlP+lMNYRo3HWRto vTwpW6V5vHA3ONvSen+RpZNC1BTEt6tPOnDQHeZNMg== X-Google-Smtp-Source: AAOMgpcKtJwNzi42oq5HonQcFxYRbP2n3Clq/7mKheB/kbNsLsPAi6qmWRdsCofPm4gnz8Cq7oe4h24a7XYap3MqN+4= X-Received: by 2002:a1f:8355:: with SMTP id f82-v6mr3326962vkd.3.1531919973576; Wed, 18 Jul 2018 06:19:33 -0700 (PDT) MIME-Version: 1.0 References: <1531918658-32278-1-git-send-email-phil.edworthy@renesas.com> <20180718130228.GG17271@n2100.armlinux.org.uk> In-Reply-To: <20180718130228.GG17271@n2100.armlinux.org.uk> From: Geert Uytterhoeven Date: Wed, 18 Jul 2018 15:19:21 +0200 Message-ID: Subject: Re: [PATCH] clk: Add functions to get optional clocks To: Russell King Cc: Phil Edworthy , Michael Turquette , Stephen Boyd , Simon Horman , Andy Shevchenko , linux-clk , Linux Kernel Mailing List , Linux ARM Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Russell, On Wed, Jul 18, 2018 at 3:02 PM Russell King - ARM Linux wrote: > On Wed, Jul 18, 2018 at 01:57:38PM +0100, Phil Edworthy wrote: > > Behaves the same as (devm_)clk_get except where there is no clock > > producer. In this case, instead of returning -ENOENT, the function > > returns NULL. This makes error checking simpler and allows > > clk_prepare_enable, etc to be called on the returned reference > > without additional checks. > > How does this work with non-DT systems, where looking a clock up which > isn't yet registered with clkdev returns -ENOENT ? > > (clkdev doesn't know when all clocks are registered with it.) Good question. I guess all drivers trying to handle optional clocks this way are already broken on non-DT systems where clocks may be registered late... 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