Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753294Ab1BCHDj (ORCPT ); Thu, 3 Feb 2011 02:03:39 -0500 Received: from LUNGE.MIT.EDU ([18.54.1.69]:34859 "EHLO lunge.queued.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752979Ab1BCHDg (ORCPT ); Thu, 3 Feb 2011 02:03:36 -0500 Date: Wed, 2 Feb 2011 23:03:26 -0800 From: Andres Salomon To: Dmitry Torokhov Cc: Samuel Ortiz , linux-kernel@vger.kernel.org, Mark Brown , Peter Ujfalusi , Liam Girdwood , Jaroslav Kysela , Takashi Iwai , Timur Tabi , linux-input@vger.kernel.org, alsa-devel@alsa-project.org Subject: Re: [PATCH 12/19] twl4030: mfd_cell is now implicitly available to drivers Message-ID: <20110202230326.167fe873@queued.net> In-Reply-To: <20110203065339.GA5592@core.coreip.homeip.net> References: <20110202195417.228e2656@queued.net> <20110202201522.72d37f1e@queued.net> <20110203060521.GA25739@core.coreip.homeip.net> <20110202223959.244b4a01@queued.net> <20110203065339.GA5592@core.coreip.homeip.net> X-Mailer: Claws Mail 3.7.6 (GTK+ 2.20.1; i486-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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2108 Lines: 53 On Wed, 2 Feb 2011 22:53:39 -0800 Dmitry Torokhov wrote: > On Wed, Feb 02, 2011 at 10:39:59PM -0800, Andres Salomon wrote: > > On Wed, 2 Feb 2011 22:05:21 -0800 > > Dmitry Torokhov wrote: > > > > > On Wed, Feb 02, 2011 at 08:15:22PM -0800, Andres Salomon wrote: > > > > static int __devinit twl4030_vibra_probe(struct platform_device > > > > *pdev) { > > > > - struct twl4030_codec_vibra_data *pdata = > > > > pdev->dev.platform_data; > > > > + struct twl4030_codec_vibra_data *pdata = > > > > platform_get_drvdata(pdev); > > > > > > No, device's drvdata belongs to _this_ driver, and it is supposed > > > to manage it and use as it sees fit. > > > > Right, so it's used to pass data to the probe function; once the > > probe function has obtained the pdata pointer, it's free to do with > > it what it will. > > > > > > > > > > Note platform_set_drvdata(pdev, info) later in this function along > > > with platform_set_drvdata(pdev, NULL) in twl4030_vibra_remove(), > > > which means that with your change you will be able to bind the > > > device only once. > > > > > > > Hm, good point; if the driver is reloaded, the pdev that was > > created by mfd-core will have lost the pointer to pdata. > > > > I wonder if I should be using mfd's driver_data instead. I used > > platform_data because a bunch of drivers had already made use of it > > to pass cell information.. > > Then they are doing it incorrectly. One possible way is to have parent > device carry relevant data in its drvdata and have children get it > from there. > I believe some drivers are even using the parent device already. See drivers/leds/leds-mc13783.c, for example, whose parent device drvdata is used to pass around a struct mc13783 to its children. Sounds like a possibility, will need to look into it further. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/