Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755786Ab1EWPKE (ORCPT ); Mon, 23 May 2011 11:10:04 -0400 Received: from mail-iy0-f174.google.com ([209.85.210.174]:61912 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754137Ab1EWPKC convert rfc822-to-8bit (ORCPT ); Mon, 23 May 2011 11:10:02 -0400 MIME-Version: 1.0 In-Reply-To: <20110523095829.GG17672@n2100.arm.linux.org.uk> References: <1305829704-11774-1-git-send-email-robherring2@gmail.com> <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> From: Grant Likely Date: Mon, 23 May 2011 09:09:41 -0600 X-Google-Sender-Auth: _r10oxzo_y-px33CLFHB2KoWfTw Message-ID: Subject: Re: [PATCH 2/2] drivers/amba: probe via device tree To: Russell King - ARM Linux Cc: Kristoffer Glembo , Kevin Hilman , Stephen Neuendorffer , Linux Kernel Mailing List , "Rafael J. Wysocki" , Jeremy Kerr , devicetree-discuss@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1932 Lines: 40 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? g. -- 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/