From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758608Ab3BVXBR (ORCPT ); Fri, 22 Feb 2013 18:01:17 -0500 Received: from avon.wwwdotorg.org ([70.85.31.133]:47508 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757867Ab3BVXBP (ORCPT ); Fri, 22 Feb 2013 18:01:15 -0500 Message-ID: <5127F8B5.10002@wwwdotorg.org> Date: Fri, 22 Feb 2013 16:01:09 -0700 From: Stephen Warren User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 MIME-Version: 1.0 To: Rhyland Klein CC: Anton Vorontsov , David Woodhouse , Grant Likely , Rob Herring , "linux-tegra@vger.kernel.org" , "devicetree-discuss@lists.ozlabs.org" , "linux-kernel@vger.kernel.org" Subject: Re: [RFC v2 2/3] power: power_supply: Add core support for supplied_nodes References: <1361488272-21010-1-git-send-email-rklein@nvidia.com> <1361488272-21010-3-git-send-email-rklein@nvidia.com> <5127CBD9.9050501@wwwdotorg.org> <5127E95E.4010500@nvidia.com> In-Reply-To: <5127E95E.4010500@nvidia.com> X-Enigmail-Version: 1.4.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/22/2013 02:55 PM, Rhyland Klein wrote: > On 2/22/2013 2:49 PM, Stephen Warren wrote: >> On 02/21/2013 04:11 PM, Rhyland Klein wrote: >>> With the growing support for dt, it make sense to try to make use of >>> dt features to make the general code cleaner. This patch is an >>> attempt to commonize how chargers and their supplies are linked. >>> >>> Following common dt convention, the "supplied-to" char** list is >>> replaced with phandle lists defined in the supplies which contain >>> phandles of their suppliers. >>> >>> This has the effect however of introducing an inversion in the internal >>> mechanics of how this information is stored. In the case of non-dt, >>> the char** list of supplies is stored in the charger. In the dt case, >>> a device_node * list is stored in the supplies of their chargers, >>> however this seems to be the only way to support this. >> When parsing the DT, you can convert from phandle (or struct device_node >> *) to the name of the referenced supply by simple lookup. So, you could >> store supply names rather than device_node *. Can't you then also fill >> in the referenced supply's existing char** list of supplies? >> >> Of course, making this interact-with/use -EPROBE_DEFERRED might be >> challenging, since this would be operating in the inverse order to other >> producer/consumer relationships, which might cause loops. > The main problem I ran into when I was essentially trying to do this, > was that the list of names that > are used to match the power_supplies are the strings set as "name" in > the power_supply structs. This > doesn't get set automatically based on their nodes, and it is currently > up to each driver to define their > own name. > > For example, the sbs-battery driver uses the name "sbs-XXX" where XX is > its dev_name. Other drivers > use "%s-$%d" as i2c_device_id->name, + instance number. Then the only > solution I see is to require a new > property that defines the power-supply's name in the devicetree. > > This solution with device_nodes, while not ideal, seems the be the best > bet from what I see. Maybe > someone else has a better idea. For other resource types, this is handled by the (phandle -> whatever) conversion process actually being a function call on the referenced object, so that the driver code for it can look up the data in the actual device/... object etc. See the various .of_xlate functions that exist in the kernel.