From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.genesi-usa.com (mithrandir.softwarenexus.net [66.98.186.96]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id 218C3DDE3C for ; Fri, 26 Oct 2007 04:12:56 +1000 (EST) Message-ID: <4720DD18.9000603@genesi-usa.com> Date: Thu, 25 Oct 2007 19:14:48 +0100 From: Matt Sealey MIME-Version: 1.0 To: Valentine Barshak Subject: Re: [linux-usb-devel] [PATCH 1/2] USB: Rework OHCI PPC OF for new bindings References: <20071024163412.GA17785@ru.mvista.com> <471FC191.6020704@genesi-usa.com> <200710241850.05467.david-b@pacbell.net> <47208273.8050601@ru.mvista.com> <4720CE3E.5030204@ru.mvista.com> In-Reply-To: <4720CE3E.5030204@ru.mvista.com> Content-Type: text/plain; charset=UTF-8; format=flowed Cc: David Brownell , linux-usb-devel@lists.sourceforge.net, linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Valentine, Please do the very minimal required to keep supporting the Efika. As for an little endian OHCI controller on an OF bus, I would not consider it an impossibility. But, not having the big-endian property fixes this; OHCI is little-endian by default. You need only report "difference" in device trees, overzealous naming of a billion kinds of 99.99999% compatible controllers is just a waste of space. I prefer the new binding to a degree. I like the big-endian property and I like the reporting of a standard controller type (usb-ohci rather than building in chip names). However by making the driver support only the recommending binding, we break old platforms for the sake of making new ones cleaner. I wish someone would have sat down and defined the 5200 device tree in a design committee rather than a peer review post-commit system. In fact, that is a great idea, we can start this off with the MPC5121E right now, and get the damn thing RIGHT. -- Matt Sealey Genesi, Manager, Developer Relations Valentine Barshak wrote: > Grant Likely wrote: >> On 10/25/07, Valentine Barshak wrote: >>> Grant Likely wrote: >>>> On 10/24/07, David Brownell wrote: >>>>> On Wednesday 24 October 2007, Matt Sealey wrote: >>>>>> Can we just make sure real quickly that the changing of compatibles >>>>>> doesn't break existing, not-easily-flashable firmwares? >>>>> Yeah, I'm not keen on such breakage either... >>>> Add my voice to the chorus. It's okay to change the binding, but make >>>> sure the old binding is still supported. >>>> >>>> Cheers, >>>> g. >>>> >>> Actually, I thought that changing the DTS stuff for mpc52xx boards would >>> suffice. Sorry, I was unaware of Efika firmware here. I'll keep old >>> bindings as well. >> >> Even if that were the case; I'm nervous about breaking compatibility >> with old device trees. > > If we keep the old bindings intact in the driver code then the old dts > files should work fine. But I'm starting to doubt we really need any new > bindings for this if we still have to keep the old ones. > BTW, does anybody know of any ohci-le devices on OF bus? > Thanks, > Valentine. > >> >> We probably need a formal guideline here. ie. When is it okay to drop >> compatibility with old dts files? >> >>> Does the device tree have "ohci-bigendian" or "ohci-be" compatible >>> property on Efika? >> >> If it doesn't, it can be added during prom_init.c We're already doing >> a bunch of efika fixups there anyway. >> >> Cheers, >> g. >> >