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=-4.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT 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 AE4D6C04EBF for ; Tue, 4 Dec 2018 07:13:45 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7BA442082D for ; Tue, 4 Dec 2018 07:13:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="P2mG0fDh" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7BA442082D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=fi.rohmeurope.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Ri7Fvftsu4yO1O8N7UlKGCe/r8h80mahKgEwKF2iI48=; b=P2mG0fDhv4rFrS IqLwfNxmdIkPARzGtMdvTARMyfXcKQ30B6gvJaLkQL5sk0pP6Opk72jUsPGxyv90sJqKrsTmEiVgV ZJLyT736ElYZ2ZuBFrqR+mR66ykluTMh8ZtJQWnUalOntXmTMXk92gCJfYijRHY0CORWwzaXspfwd gws/XWHsgSkG9QtOiGKcuEtVTvfqBHC78yHZLiwXjKLM2WDMpRaIJBFcNYiNhNF4yynq3jkeyAkoh gO6wrsHv4H9F2kD/0cHE62Rs3+QUtFCtGYKnTt/Poq/1cbHiJaSIlGHbrRxEWill4w/8NCy75WIUY BaoQY3NuoSTqUgxPrLFw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gU4tq-0002tY-70; Tue, 04 Dec 2018 07:13:42 +0000 Received: from mail-lj1-f196.google.com ([209.85.208.196]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gU4tm-0002sV-Fo for linux-arm-kernel@lists.infradead.org; Tue, 04 Dec 2018 07:13:40 +0000 Received: by mail-lj1-f196.google.com with SMTP id v15-v6so13854906ljh.13 for ; Mon, 03 Dec 2018 23:13:27 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=xmeezsH2L85SbH1REd44WuAJXxNc3UqWGXKyi96Uj28=; b=eIbtJPF/AJgl3CCmBJfOrAmxrg0TRzifnqjkCNqvQHs0Bos9pkrNRF8Ks4WfLVuRCX ggQG+fkRQA2i2bhcBfgpRA+NA84JUm78IcKDqMRoLB62bDDFtnQLfAaotkhkO/I+ONKM sWJmaNEVqcakYHNgBj3P3JfpRSxwrEiiMfuPS0LfVlyWAPu4uDoTvzKX17pTyAuJMz4J ajSQG58r/JiS6wWZjeUNkIQsQbDuM5Pl+GOXg4Inx9A8QZpYqODluoVFfUCK0IoGnl98 ZviKQa5VKgY+ATV5X2wWK4zmRR8SIMYkY1m/6NMYvDNkqkuaiWebsvTXbxvohSTgECY4 MvsQ== X-Gm-Message-State: AA+aEWb8WlNwjNs0xHipP+3a/NxffjhW3CxcM+HaHEy9+OM7OiDCvepG qeKKp+N8FO+AxXwzmjfx8UQ= X-Google-Smtp-Source: AFSGD/XYIGAw29yRvRUedjQ9g4fIn0B0FHC5J9uW9shhq4igz9NfvdIuMojadcAS7atDvAZfLd0dxQ== X-Received: by 2002:a2e:4299:: with SMTP id h25-v6mr11561739ljf.5.1543907605271; Mon, 03 Dec 2018 23:13:25 -0800 (PST) Received: from localhost.localdomain ([213.255.186.46]) by smtp.gmail.com with ESMTPSA id x204sm2789009lfa.5.2018.12.03.23.13.23 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 03 Dec 2018 23:13:24 -0800 (PST) Date: Tue, 4 Dec 2018 09:13:15 +0200 From: Matti Vaittinen To: Stephen Boyd Subject: Re: [PATCH v4 1/8] clk: clkdev/of_clk - add managed lookup and provider registrations Message-ID: <20181204071315.GA31204@localhost.localdomain> References: <154356805035.88331.16867826308376667832@swboyd.mtv.corp.google.com> <20181130105022.GA15388@localhost.localdomain> <154388011043.88331.6461709079501929390@swboyd.mtv.corp.google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <154388011043.88331.6461709079501929390@swboyd.mtv.corp.google.com> User-Agent: Mutt/1.9.2 (2017-12-15) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20181203_231338_533173_4A375C62 X-CRM114-Status: GOOD ( 44.83 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-doc@vger.kernel.org, Michael Turquette , Daniel Kurtz , Sebastian Reichel , David Brown , linux-clk@vger.kernel.org, Rob Herring , Jonathan Corbet , Andrey Smirnov , "Rafael J. Wysocki" , Russell King , Krzysztof Kozlowski , Chanwoo Choi , Andy Gross , Huang Shijie , Guenter Roeck , Bartlomiej Zolnierkiewicz , linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Akshu Agrawal , mazziesaccount@gmail.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hello Again Stephen, I did already send v5 prior to your reply but I will create v6 today based on this discussion. On Mon, Dec 03, 2018 at 03:35:10PM -0800, Stephen Boyd wrote: > Quoting Matti Vaittinen (2018-11-30 02:50:22) > > Hello Stephen, > > > > Thanks a bunch for taking the time and reviewing this! > > > > On Fri, Nov 30, 2018 at 12:54:10AM -0800, Stephen Boyd wrote: > > > Quoting Matti Vaittinen (2018-11-13 03:55:58) > > > > -int devm_of_clk_add_hw_provider(struct device *dev, > > > > +static int __devm_of_clk_add_hw_provider(struct device *dev, > > > > struct clk_hw *(*get)(struct of_phandle_args *clkspec, > > > > void *data), > > > > - void *data) > > > > + struct device_node *of_node, void *data) > > > > { > > > > - struct device_node **ptr, *np; > > > > + struct device_node **ptr; > > > > int ret; > > > > > > > > ptr = devres_alloc(devm_of_clk_release_provider, sizeof(*ptr), > > > > @@ -3906,10 +3906,9 @@ int devm_of_clk_add_hw_provider(struct device *dev, > > > > if (!ptr) > > > > return -ENOMEM; > > > > > > > > - np = dev->of_node; > > > > - ret = of_clk_add_hw_provider(np, get, data); > > > > + *ptr = of_node; > > > > + ret = of_clk_add_hw_provider(of_node, get, data); > > > > if (!ret) { > > > > - *ptr = np; > > > > > > Why is this moved outside of the if condition? > > I completely removed the local variable np and just unconditionally set > > the allocated devres to point at the node (if allocation succeeded). We > > could of course only do this if the provider registration succeeded and > > save one assignment - but I guess I intended to remove the curly braces > > and thus decided to go for one liner after if. But apparently I didn't > > remove the braces O_o. Well, I can put the assignment inside the > > condition if you prefer that. > > > > > In fact, why isn't just > > > the first line in this hunk deleted and passed to this function as > > > struct device_node *np? > > > > I am sorry but I don't quite follow your suggestion here. Do you mean we > > could just pass the struct device_node *np in devres_add()? I thought > > the pointer passed to devress_add() should be allocated using > > devres_alloc. Can you please elaborate what you mean? > > I'm just trying to reduce the diff in the patch. Oh, right. I will see how renaming the argument to np would impact to patch size. iActually, I never consider the patch size at all - I have only been concentrating on how the resulting file looks like. It didn't ever cross my mind that patch size matters. But I guess the size of chanes is really meaningfull when the amount of changes is large. > > > > devres_add(dev, ptr); > > > > } else { > > > > devres_free(ptr); > [..] > > > > > > > +int devm_of_clk_add_hw_provider(struct device *dev, > > > > + struct clk_hw *(*get)(struct of_phandle_args *clkspec, > > > > + void *data), > > > > + void *data) > > > > +{ > > > > + return __devm_of_clk_add_hw_provider(dev, get, dev->of_node, data); > > > > +} > > > > EXPORT_SYMBOL_GPL(devm_of_clk_add_hw_provider); > > > > > > > > +int devm_of_clk_add_parent_hw_provider(struct device *dev, > > > > + struct clk_hw *(*get)(struct of_phandle_args *clkspec, > > > > + void *data), > > > > + void *data) > > > > +{ > > > > + return __devm_of_clk_add_hw_provider(dev, get, dev->parent->of_node, > > > > > > I'm wondering if we can somehow auto-detect this in > > > devm_of_clk_add_hw_provider() by looking for #clock-cells in the node. > > > If it isn't there, then we go to the parent node and look for a > > > #clock-cells property there in the DT node for that device. Does that > > > make sense? Then there isn't any new API and we can attach the lifetime > > > of the devm registration to the presence of the property indicating this > > > is a clk controller or not. > > > > Huh. I don't know why but building this kind of logic in core is a bit > > scary to me. I guess I can try implementing something like this - but I > > am not really a fan of this. (Accidentally) omit the #clock-cells from > > node and we go to parent node - I am a novice on this area but this > > sounds like a potential hazard to me. I believe the driver should know > > if it's properties should be in own or parent node - and if they are > > not, then there should be no guessing but error. The lifetime is topic > > where I would like to get information from you who know the kernel > > better than I do =) But I guess the parent node is there at least as > > long as the child device is alive. So for me the life time of > > get-callback is more crucial - but as I said, I don't understand the > > kernel in details so you probably know it better than me. But please let > > me know your final take on this and I will follow the guidance =) > > Please do the magic instead of adding another API. It makes things > simpler and will work for this case without having to change anything > besides of_clk_add_provider(). All right. Let's go on this direction then. > If the DT doesn't have the #clock-cells property in the node being > registered then calling clk_get() will fail for any consumer devices > that point to the node with a phandle and clock specifier. I don't > expect us to get very far into development if that's the case. Makes sense. So only potential thing to break is if someone out there has broken DT/driver - where they currently see this failure. Eg. they use node w/o #clock-cells as provider and where they try and fail controlling this clock - but ignore the error (and system just "works" with HW defaults). After this change they may actually succeed in controlling - but do control wrong clock. Not likely scenario (sure happens somewhere) - and it involves already broken design. So I agree with you. Besides, you are the maintainer for clk framework and thus get the most of the rain if **** hits the fan =D > Of course, we don't fail in of_clk_add_provider() if there isn't a > #clock-cells property in the node, we just happily add the node to the > provider list and carry on. I doubt anyone is failing to specify the DT > property, but maybe they are, in which case we could keep not failing > and just add the node of whatever we're called with originally if > neither the parent or the passed node have the #clock-cells property. I > wouldn't try to go any higher than one node above the current node and > look for a #clock-cells though. I think we should use parent device's node, not the paren node in DT, right? But I agree, we should only look "one level up in the chain". > > If this all still seems scary then don't worry about it, I'll implement > it myself. It still is somewhat "scary" - but I really would like to use the devm based provider registration in the bd718x7 driver so I will implement it in this series. The engineer version of the "living on the edge", you know =) Br, Matti Vaittinen -- Matti Vaittinen ROHM Semiconductors ~~~ "I don't think so," said Rene Descartes. Just then, he vanished ~~~ _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel