[PATCH] ARM: dts: mvebu: add ethernet to the cm-a510 board

David Goodenough david.goodenough at btconnect.com
Fri Jan 30 04:44:56 PST 2015

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 <sebastian.hesselbarth at gmail.com> wrote:
> >> Adapting the .config and removing drivers is actually not an option.
> >> IMHO, introducing DT was meant for a single multi-arch kernel that
> >> can be shipped with common Linux distros. Therefore, DT is the place
> >> you enable/disable available resources. You leave most of the SoC (and
> >> SoM) nodes disabled as long as you cannot tell if there is a
> >> corresponding connector available.
> > 
> > Well, I don't know too much about the hardware, and less about the
> > hardware modules (SoM?).
> Sorry, SoM is for System-on-Module, i.e. the CM-A510 itself.
> You can see from the block diagram that it comprises the Dove SoC,
> power circuitry, touch-screen controller, WiFi, GbE PHY for GbE-0, GbE
> controller on PCIe for GbE-1, I2S audio codec, RS232 Level Shifter for
> UART0, an USB2 Hub, SPI flash, NAND and RAM.
> That basically is what will be represented in the som.dtsi. If any of
> the functions above and the SoC will be _accessible_ on the baseboard is
> another story.
> > As seen in the Compulab documents, there are a lot of hardware modules.
> > For the DT, do you mean that there would be as many .dts's as the whole
> > number of connection possibilities?
> Nope. One dove.dtsi, one dove-cm-a510.dtsi, and one baseboard.dts
> including dove-cm-a510.dtsi for every baseboard we stumble upon.
> > I'd have better seen the inverted case as the actual empty cm-board dts:
> > enable every option in the (generic) .dts and let the vendor/user create
> > a specific .dts from this one for the board according to the installed
> > modules.
> 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.

> Sebastian
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