From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grant Likely Subject: Re: [PATCH 2/2] drivers/amba: probe via device tree Date: Mon, 23 May 2011 09:09:41 -0600 Message-ID: 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> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20110523095829.GG17672-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org To: Russell King - ARM Linux Cc: Kevin Hilman , Linux Kernel Mailing List , "Rafael J. Wysocki" , Jeremy Kerr , devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org 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. =A0The 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. =A0All I had to go > on were the primecell documents themselves. =A0The 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.