Messages in this thread | | | From | Grant Likely <> | Date | Mon, 23 May 2011 09:09:41 -0600 | Subject | Re: [PATCH 2/2] drivers/amba: probe via device tree |
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On Mon, May 23, 2011 at 3:58 AM, Russell King - ARM Linux <linux@arm.linux.org.uk> 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?
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