From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763676AbdAKOjZ (ORCPT ); Wed, 11 Jan 2017 09:39:25 -0500 Received: from metis.ext.4.pengutronix.de ([92.198.50.35]:35773 "EHLO metis.ext.4.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751778AbdAKOjX (ORCPT ); Wed, 11 Jan 2017 09:39:23 -0500 Date: Wed, 11 Jan 2017 15:39:17 +0100 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= To: Marc Gonzalez Cc: Guenter Roeck , Wim Van Sebroeck , linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Mans Rullgard , Thibaud Cornic , Mark Rutland , Arnd Bergmann Subject: Re: [PATCH 56/62] watchdog: tangox_wdt: Convert to use device managed functions Message-ID: <20170111143917.hedhyfu6m5dopag7@pengutronix.de> References: <1484091325-9199-1-git-send-email-linux@roeck-us.net> <1484100561-17638-1-git-send-email-linux@roeck-us.net> <1484100561-17638-5-git-send-email-linux@roeck-us.net> <94c4d5c0-f639-eab1-6706-335977690e88@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.6.2-neo (2016-06-11) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c5 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 11, 2017 at 01:31:47PM +0100, Marc Gonzalez wrote: > On 11/01/2017 11:52, Guenter Roeck wrote: > > > On 01/11/2017 01:07 AM, Marc Gonzalez wrote: > > > >>> @@ -134,12 +134,15 @@ static int tangox_wdt_probe(struct platform_device *pdev) > >>> err = clk_prepare_enable(dev->clk); > >>> if (err) > >>> return err; > >>> + err = devm_add_action_or_reset(&pdev->dev, > >>> + (void(*)(void *))clk_disable_unprepare, > >>> + dev->clk); > >>> + if (err) > >>> + return err; This looks wrong. There is no clk_unprepare_disable when devm_add_action_or_reset fails. > >> > >> Hello Guenter, > >> > >> I would rather avoid the function pointer cast. > >> How about defining an auxiliary function for the cleanup action? > >> > >> clk_disable_unprepare() is static inline, so gcc will have to > >> define an auxiliary function either way. What do you think? > > > > Not really. It would just make it more complicated to replace the > > call with devm_clk_prepare_enable(), should it ever find its way > > into the light of day. > > More complicated, because the cleanup function will have to be deleted later? > The compiler will warn if someone forgets to do that. > > In my opinion, it's not a good idea to rely on the fact that casting > void(*)(struct clk *clk) to void(*)(void *) is likely to work as expected > on most platforms. (It has undefined behavior, strictly speaking.) I would expect it to work on all (Linux) platforms. Anyhow, I wonder if there couldn't be found a better solution. If in the end it looks like the following that would be good I think: clk = devm_clk_get(...); if (IS_ERR(clk)) ... ret = devm_clk_prepare_enable(clk) if (ret) return ret; ... Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |