Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754822Ab1EYC54 (ORCPT ); Tue, 24 May 2011 22:57:56 -0400 Received: from tx2ehsobe003.messaging.microsoft.com ([65.55.88.13]:34923 "EHLO TX2EHSOBE006.bigfish.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752177Ab1EYC5z (ORCPT ); Tue, 24 May 2011 22:57:55 -0400 X-SpamScore: -19 X-BigFish: VS-19(zzbb2dK9371O1432N98dKzz1202hzzz2dh2a8h668h839h) X-Forefront-Antispam-Report: CIP:70.37.183.190;KIP:(null);UIP:(null);IPVD:NLI;H:mail.freescale.net;RD:none;EFVD:NLI Date: Wed, 25 May 2011 11:02:26 +0800 From: Shawn Guo To: Rob Herring CC: Grant Likely , Kevin Hilman , Russell King - ARM Linux , , Linux Kernel Mailing List , "Rafael J. Wysocki" , Jeremy Kerr , Subject: Re: [PATCH 2/2] drivers/amba: probe via device tree Message-ID: <20110525030225.GA30394@S2100-06.ap.freescale.net> References: <20110519233958.GB18181@ponder.secretlab.ca> <4DD66B8A.5040404@gmail.com> <201105201621.03801.arnd@arndb.de> <4DD68614.6090209@gmail.com> <4DDA2AC0.1060406@gaisler.com> <20110523095829.GG17672@n2100.arm.linux.org.uk> <4DDBC8C7.4000001@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <4DDBC8C7.4000001@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-OriginatorOrg: freescale.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2564 Lines: 58 On Tue, May 24, 2011 at 10:03:35AM -0500, Rob Herring wrote: > Grant, > > On 05/23/2011 10:09 AM, Grant Likely wrote: > >On Mon, May 23, 2011 at 3:58 AM, Russell King - ARM Linux > > wrote: > >>On Mon, May 23, 2011 at 11:37:04AM +0200, Kristoffer Glembo wrote: > >>>Grant Likely wrote: > >>>>In the case we're talking about the bus really is an AMBA bus, and all > >>>>the devices on it are in some sense real amba devices. The problem is > >>>>that not all of the devices on the bus implement peripheral ID > >>>>registers or other mechanisms that good upstanding AMBA devices are > >>>>expected to have. > >>> > >>>Before we go hardware bashing of non primecell AMBA devices I would just > >>>want to point out that the primecell stuff is not part of the AMBA > >>>specification. > >> > >>And before we go down that route, let me point out that the 'amba bus' > >>stuff in the kernel is there to support primecells, rather than all > >>devices which the AMBA specification covers. > >> > >>The reason it's called 'amba' is because back in 2001 or so when the > >>first primecell drivers were created, there was little information > >>available as to what AMBA, AHB, or APB even covered. All I had to go > >>on were the primecell documents themselves. The higher level documents > >>were not available to me. > >> > >>So, despite it being called 'amba', it really is just for primecells > >>and if we didn't have the exposure to userspace, I'd have renamed it to > >>'apb' or similar instead. > > > >Okay, that clarifies things a lot, and lends weight to the arguement > >that it is perfectly normal and acceptable to have both amba_devices > >and platform_devices on the same bus segment. Are there any cases > >where amba primecells are being driven by platform_drivers? If so, > >should those drivers have an amba_driver registration added? > > I would be surprised if there are any implemented as > platform_drivers that are not duplicates of an amba driver. The STMP > uart is actually a pl011 and it's platform driver was recently It (duart than auart) is a platform driver in Freesccale BSP, and was turned into 'amba' one when being upstreamed. > removed IIRC. So I think we can consider platform drivers something > that should be fixed in this case. > -- Regards, Shawn -- 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/