From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752896AbaG1Nhi (ORCPT ); Mon, 28 Jul 2014 09:37:38 -0400 Received: from service87.mimecast.com ([91.220.42.44]:57226 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752361AbaG1Nhb convert rfc822-to-8bit (ORCPT ); Mon, 28 Jul 2014 09:37:31 -0400 Message-ID: <53D65236.7080606@arm.com> Date: Mon, 28 Jul 2014 14:37:58 +0100 From: Sudeep Holla User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Stephen Boyd CC: Sudeep Holla , LKML , Heiko Carstens , Lorenzo Pieralisi , Greg Kroah-Hartman Subject: Re: [PATCH v2 1/9] drivers: base: add new class "cpu" to group cpu devices References: <1403717444-23559-1-git-send-email-sudeep.holla@arm.com> <1406306692-7135-1-git-send-email-sudeep.holla@arm.com> <1406306692-7135-2-git-send-email-sudeep.holla@arm.com> <53D2AB54.5030809@codeaurora.org> In-Reply-To: <53D2AB54.5030809@codeaurora.org> X-OriginalArrivalTime: 28 Jul 2014 13:37:27.0630 (UTC) FILETIME=[128926E0:01CFAA69] X-MC-Unique: 114072814372803301 Content-Type: text/plain; charset=WINDOWS-1252; format=flowed Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 25/07/14 20:09, Stephen Boyd wrote: > On 07/25/14 09:44, Sudeep Holla wrote: >> From: Sudeep Holla >> >> This patch creates a new class called "cpu" and assigns it to all the >> cpu devices. This helps in grouping all the cpu devices and associated >> child devices under the same class. >> >> This patch also: >> 1. modifies the get_parent_device to return the legacy path >> (/sys/devices/system/cpu/..) for the cpu class devices to support >> existing sysfs ABI >> 2. avoids creating link in the class directory pointing to the device as >> there would be per-cpu instance of these devices with the same name >> 3. makes sure subsystem symlink continues pointing to cpu bus instead of >> cpu class for cpu devices >> >> Signed-off-by: Sudeep Holla >> Cc: Greg Kroah-Hartman > > Why can't we make a 'cache' bus that the cache devices hang off of? It > doesn't make sense to me why we would want to have cache devices living > on the cpu bus. > Yes we can group them under cache, but to support legacy sysfs path under which various cpu related information including caches, we need to have a workaround as in this patch. Instead of having this fixup for each class like cache, having them grouped under cpu is better IMO and hence I added caches to cpu class. It also helps to move few other cpu related subsystems using raw kobjects to the device attribute groups and corresponding APIs. Regards, Sudeep