Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965600AbbDVQLV (ORCPT ); Wed, 22 Apr 2015 12:11:21 -0400 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:42901 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754619AbbDVQLT (ORCPT ); Wed, 22 Apr 2015 12:11:19 -0400 Message-ID: <1429719077.2195.37.camel@HansenPartnership.com> Subject: Re: [PATCH v4 2/2] efi: an sysfs interface for user to update efi firmware From: James Bottomley To: Greg Kroah-Hartman Cc: "Kweh, Hock Leong" , Ming Lei , Matt Fleming , "Ong, Boon Leong" , LKML , "linux-efi@vger.kernel.org" , Sam Protsenko , Peter Jones , Andy Lutomirski , Roy Franz , Borislav Petkov Date: Wed, 22 Apr 2015 09:11:17 -0700 In-Reply-To: <20150422154620.GA32576@kroah.com> References: <1429004697-28320-1-git-send-email-hock.leong.kweh@intel.com> <1429004697-28320-3-git-send-email-hock.leong.kweh@intel.com> <20150414140914.GE5989@kroah.com> <20150415131906.GC21491@kroah.com> <1429716954.2195.28.camel@HansenPartnership.com> <20150422154620.GA32576@kroah.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.12.11 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2832 Lines: 59 On Wed, 2015-04-22 at 17:46 +0200, Greg Kroah-Hartman wrote: > On Wed, Apr 22, 2015 at 08:35:54AM -0700, James Bottomley wrote: > > On Wed, 2015-04-15 at 15:19 +0200, Greg Kroah-Hartman wrote: > > > On Wed, Apr 15, 2015 at 11:32:29AM +0000, Kweh, Hock Leong wrote: > > > > > -----Original Message----- > > > > > From: Greg Kroah-Hartman [mailto:gregkh@linuxfoundation.org] > > > > > Sent: Tuesday, April 14, 2015 10:09 PM > > > > > > > > > > On Tue, Apr 14, 2015 at 05:44:56PM +0800, Kweh, Hock Leong wrote: > > > > > > + */ > > > > > > +static void __exit efi_capsule_loader_exit(void) > > > > > > +{ > > > > > > + platform_device_unregister(efi_capsule_pdev); > > > > > > > > > > This is not a platform device, don't abuse that interface please. > > > > > > > > > > greg k-h > > > > > > > > Okay, so you would recommend to use device_register() for this case? > > > > Or you would think that this is more suitable to use class_register()? > > > > > > A class isn't needed, you just want a device right? So just use a > > > device, but not a platform device, as that isn't what you have here. > > > > Coming back to this, am I the only one confused here? What is a > > 'platform device' then? Because if it doesn't fit a direct channel to > > the platform firmware, which seems to be one of the definitions covered > > in driver-model/platform.txt under devices with minimal infrastructure > > then perhaps the documentation needs updating. > > I don't remember the original code here at all, sorry. I'm guessing > that they were using a class, and a platform device together, which is > not a good idea. Just make a "virtual" device, as you don't need/want > any of the platform device infrastructure here, you just wanted a device > node and/or a way to show up in sysfs somewhere. It was a platform device called efi_platform_loader and a single attribute file in that device called capsule_load. I agree that if we're going to use this for other things, we should probably have a uefi directory somewhere (under firmware?) to collect everything together rather than spraying random devices around. > If you have some kind of "platform resource", then you can be a platform > device, otherwise please don't use that api just because it seems simple > to use. Use the ones the driver core provides for you that really are > just as simple (i.e. device_create()). OK, so this is what I'm trying to understand. Why isn't a pipe to firmware for something a "platform resource"? I think UEFI is in the same class as ACPI which uses platform devices all over. James -- 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/