From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753787Ab3IWUqN (ORCPT ); Mon, 23 Sep 2013 16:46:13 -0400 Received: from avon.wwwdotorg.org ([70.85.31.133]:51113 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752995Ab3IWUqK (ORCPT ); Mon, 23 Sep 2013 16:46:10 -0400 Message-ID: <5240A88D.8030309@wwwdotorg.org> Date: Mon, 23 Sep 2013 14:46:05 -0600 From: Stephen Warren User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130803 Thunderbird/17.0.8 MIME-Version: 1.0 To: Lee Jones CC: Laxman Dewangan , Mark Brown , "sameo@linux.intel.com" , "rob.herring@calxeda.com" , "pawel.moll@arm.com" , "mark.rutland@arm.com" , "ijc+devicetree@hellion.org.uk" , "rob@landley.net" , "devicetree@vger.kernel.org" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] mfd: core: introduce of_node_name for mfd sub devices References: <1379579392-1794-1-git-send-email-ldewangan@nvidia.com> <20130919083050.GH16984@lee--X1> <20130919115501.GM21013@sirena.org.uk> <20130919120051.GG22389@lee--X1> <523AEE07.9090405@nvidia.com> <20130919122240.GI22389@lee--X1> In-Reply-To: <20130919122240.GI22389@lee--X1> X-Enigmail-Version: 1.4.6 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/19/2013 06:22 AM, Lee Jones wrote: >>>>> Do the sub-nodes have their own properties? If so, it would be worth >>>>> breaking them up as other OSes could reuse the specifics. If they do, >>>>> then you need so put them in the binding. If they don't, then you do >>>>> not require sub-nodes. The MFD core will ensure the sub-devices are >>>>> probed and there is no requirement for the of_node to be assigned. >>>> You do see some reusable IP blocks (like the regualtors on the wm831x >>>> PMICs for example, they're repeated blocks) which can be reused but >>>> generally they have a register base as part of the binding. Personally >>>> if it's just a property or two I'd probably just put them on the root >>>> node for the device. >>> Agreed. Besides, there doesn't seem to be *any* sub-device properties >>> defined in the binding document. So what are you trying to achieve >>> with the child nodes? >> >> I wanted to have the DT like: >> >> as3722 { >> compatible = "ams,as3722"; >> reg = <0x40>; >> >> #interrupt-controller; >> ..... >> >> >> regulators { >> ldo1-in-supply = <..>; >> .... >> sd0 { >> regulator-name = "vdd-cpu"; >> ..... >> }; >> sd1 { >> regulator-name = "vdd-ddr"; >> ..... >> }; >> .... >> }; >> }; >> >> And regulator driver should get the regulator node by their >> pdev->dev.of_node. >> Currently, in most of driver, we are having the code on regulator >> driver to get "regulators" node from parent node which I want to >> avoid. > > Ah, I see. Yes, I believe the regulators should have their own node, The use of a "regulators" node to keep all the regulator configuration in one place seems fine... > complete with a compatible string. ... but I see not reason why that node has to have a separate compatible property, or /has/ to have a separate driver. I think having a compatible value in this node would only be required if the HW block that implements those registers is actually expected to be shared between n different chips, and hence it's likely that you'd get re-use out of a separate binding, driver, etc. It's perfectly reasonable for the regulator MFD driver to know that the binding for the top-level PMIC node has a regulators child node, and go find it by name, and read whatever properties/nodes it needs directly out of it. Writing code that way in no ways implies a need for a compatible value. > To have each regulator listed > separately in the parent node seems a little messy. Just out of > interest, how many regulators are we talking about here?