Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753851AbbKETwy (ORCPT ); Thu, 5 Nov 2015 14:52:54 -0500 Received: from mail-yk0-f181.google.com ([209.85.160.181]:35167 "EHLO mail-yk0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751244AbbKETww convert rfc822-to-8bit (ORCPT ); Thu, 5 Nov 2015 14:52:52 -0500 MIME-Version: 1.0 In-Reply-To: References: <1445368397-8732-1-git-send-email-pantelis.antoniou@konsulko.com> <1445368397-8732-4-git-send-email-pantelis.antoniou@konsulko.com> <8A0C91DE-EDF8-449D-918C-95C9807A7616@konsulko.com> <1148C5AF-CA7C-44CE-9CBD-BCD949C6B5FD@konsulko.com> From: Rob Herring Date: Thu, 5 Nov 2015 13:52:31 -0600 Message-ID: Subject: Re: [PATCH v6 3/4] of: overlay: add per overlay sysfs attributes To: Pantelis Antoniou Cc: Frank Rowand , Matt Porter , Koen Kooi , Guenter Roeck , Greg Kroah-Hartman , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-api@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2757 Lines: 76 On Thu, Oct 22, 2015 at 11:15 AM, Pantelis Antoniou wrote: > Hi Rob, > >> On Oct 22, 2015, at 00:52 , Rob Herring wrote: >> >> On Wed, Oct 21, 2015 at 2:37 PM, Pantelis Antoniou >> wrote: >>> Hi Rob, >>> >>>> On Oct 21, 2015, at 00:54 , Rob Herring wrote: >>>> >>>> On Tue, Oct 20, 2015 at 4:11 PM, Pantelis Antoniou >>>> wrote: >>>>> Hi Rob, >>>>> >>>>>> On Oct 21, 2015, at 00:04 , Rob Herring wrote: >>>>>> >>>>>> On Tue, Oct 20, 2015 at 2:13 PM, Pantelis Antoniou >>>>>> wrote: >>>>>>> * A per overlay can_remove sysfs attribute that reports whether >>>>>>> the overlay can be removed or not due to another overlapping overlay. >>>>>>> >>>>>>> * A target sysfs attribute listing the target of each fragment, >>>>>>> in a group named after the name of the fragment. >>>> >>>> [...] >>>> >>>>>>> @@ -255,6 +278,17 @@ err_fail: >>>>>>> return -EINVAL; >>>>>>> } >>>>>>> >>>>>>> +static ssize_t target_show(struct kobject *kobj, >>>>>>> + struct fragment_attribute *fattr, char *buf) >>>>>>> +{ >>>>>>> + struct of_overlay_info *ovinfo = fattr->ovinfo; >>>>>>> + >>>>>>> + return snprintf(buf, PAGE_SIZE, "%s\n", >>>>>>> + of_node_full_name(ovinfo->target)); >>>>>> >>>>>> This can be a link to the node itself, can't it? >>>>>> >>>>> >>>>> Yes. Do you want it like this? >>>> >>>> Yes, hence the suggestion. Unless you see some reason why not. >>>> >>> >>> Nope, can’t be done. The sysfs API only allows linking one kobj to another. >>> The kobj is the overlay but the target is in the fragment attribute group. >> >> Can't we make the fragments kobj's as well? >> > > We could, but it break the mental model of what a kobj should represent. > An overlay is an object which can be address, a fragment is never directly > exposed. But you are exposing fragments as there is a directory for each one. Overlays are just logical collections of fragments. You could go as far to say overlays don't need to be exposed at all and only fragments need to be (not that we should). We already have overlays and nodes as kobjs, so I don't think fragments as kobjs breaks the mental model. > TBH a link attribute is indeed better than a path attribute, but marginally so. > It’s not worth the trouble IMO. It is just an ABI we have to support forever... Rob -- 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/