From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from wolverine01.qualcomm.com ([199.106.114.254]:22710 "EHLO wolverine01.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932131Ab0HDAR7 (ORCPT ); Tue, 3 Aug 2010 20:17:59 -0400 Message-ID: <4C58B1B6.9050005@quicinc.com> Date: Tue, 3 Aug 2010 17:17:58 -0700 From: Patrick Pannuto MIME-Version: 1.0 Subject: Re: [RFC PATCH] platform: Faciliatate the creation of pseduo-platform busses References: <4C58A7AA.8020007@codeaurora.org> <20100803235631.GA17759@suse.de> <4C58AE15.6090900@codeaurora.org> <20100804000945.GA19729@suse.de> In-Reply-To: <20100804000945.GA19729@suse.de> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: linux-arm-msm-owner@vger.kernel.org List-ID: To: Greg KH Cc: Patrick Pannuto , "linux-kernel@vger.kernel.org" , "linux-arm-msm@vger.kernel.org" , "linux-omap@vger.kernel.org" , "damm@opensource.se" , "lethal@linux-sh.org" , "rjw@sisk.pl" , "dtor@mail.ru" , "eric.y.miao@gmail.com" , "netdev@vger.kernel.org" >>>> >>>> struct platform_device sub_bus1 = { >>>> .name = "sub_bus1", >>>> .id = -1, >>>> .dev.bus = &my_bus_type, >>>> } >>>> EXPORT_SYMBOL_GPL(sub_bus1); >>> >>> You really want a bus hanging off of a bus? Normally you need a device >>> to do that, which is what I think you have here, but the naming is a bit >>> odd to me. >>> >>> What would you do with this "sub bus"? It's just a device, but you are >>> wanting it to be around for something. >>> >> >> It's for power management stuff, basically, there are actual physical buses >> involved that can be completely powered off IFF all of their devices are >> not in use. Plus it actually matches bus topology this way. > > Then create a real bus hanging off of a device, not another device that > "acts" like a bus here, right? Or am I missing the point? > The motivation for doing it this was is that one driver could drive devices on two different subbusses. In the example, "my-driver" could drive a device on sub_bus1 AND sub_bus2 (if there were 2+ devices, one or more on each bus). >>From my understanding, this is not possible if they are actually different busses.