From mboxrd@z Thu Jan 1 00:00:00 1970 From: sebastian.hesselbarth@gmail.com (Sebastian Hesselbarth) Date: Fri, 30 Jan 2015 14:07:55 +0100 Subject: [PATCH] ARM: dts: mvebu: add ethernet to the cm-a510 board In-Reply-To: <1507191.iMZ4oC8rrr@stargate> References: <20150130124144.501cf81d@armhf> <54CB732F.7010409@gmail.com> <1507191.iMZ4oC8rrr@stargate> Message-ID: <54CB822B.8080809@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org [Re-adding the most obvious People to Cc] On 30.01.2015 13:44, David Goodenough wrote: > On Friday 30 January 2015 13:03:59 Sebastian Hesselbarth wrote: >> On 30.01.2015 12:41, Jean-Francois Moine wrote: >>> On Fri, 30 Jan 2015 12:00:16 +0100 >>> Sebastian Hesselbarth wrote: >> That what dtsi's are made for with one exception: the dtsi cannot "run" >> on its own but needs at least one baseboard.dts that includes it. We >> could create a "bare"-baseboard that represents what is (easily) >> accessible on the SoM itself. Given the fact that even UART0 needs a >> baseboard that grabs it from the SoM connector, I see no value in that. >> >>> In any case, any real cm-a510 board should work with the >>> generic/full .dts even if some hardware modules are lacking. No? >> >> Nope. The cm-a510 is just an add-on for a baseboard, it does not make >> a working board. Just think of it as a feature-improved SoC. > This sounds like capes on the BeagleBoard. Are these extension boards > self-identifying? If so then the approach used with the capes might work > here too. David, IMHO capes are a different thing. The BB can run just fine without any cape installed, the cm-a510 cannot run without a baseboard. Also, once you have your SoM installed it cannot change over runtime, there is no need for any dynamic overlays and such. You can build some 5 or 10 different configurations given the SoM and a specific baseboard but not hundreds of possible combinations. Besides, Gabriel is the first in almost 2 years that actually has an cm-a510 - so, I doubt we'll have to mainline dozens of baseboards using the cm-a510 in the near future. Regarding the self-identification, it would be great if the actual SoM configuration would be stored in the (always available) SPI flash, but from my experience with the boards I have seen so far, I have a bad feeling about it ;) A quick look at the sb-a510 (the compulab baseboard for cm-a510) suggests that there is more configuration available but by jumpers that (hopefully) can be read out by GPIOs at least. The best similar board available in mainline I can remember is the SolidRun Hummingboard, i.e. one baseboard that can be equipped with 3-4 different SoMs. Sebastian