Messages in this thread | | | Subject | Re: [RFC] Device Tree Overlays Proposal (Was Re: capebus moving omap_devices to mach-omap2) | From | Koen Kooi <> | Date | Mon, 12 Nov 2012 12:03:23 +0100 |
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Op 5 nov. 2012, om 21:40 heeft Grant Likely <grant.likely@secretlab.ca> het volgende geschreven:
> Hey folks, > > As promised, here is my early draft to try and capture what device > tree overlays need to do and how to get there. Comments and > suggestions greatly appreciated. > > Device Tree Overlay Feature > > Purpose > ======= > Sometimes it is not convenient to describe an entire system with a > single FDT. For example, processor modules that are plugged into one or > more modules (a la the BeagleBone), or systems with an FPGA peripheral > that is programmed after the system is booted. > > For these cases it is proposed to implement an overlay feature for the > so that the initial device tree data can be modified by userspace at > runtime by loading additional overlay FDTs that amend the original data. > > User Stories > ============ > Note - These are potential use cases, but just because it is listed here > doesn't mean it is important. I just want to thoroughly think through the > implications before making design decisions.
I think the beaglebone use cases cover it as well, but it deserves a seperate mention: SOMs. Gumstix is a good example of those, their website has a list of the different expansionboards they sell so we can see if we missed a use case somewhere. Their expansionboards have an EEPROM to ID them, just like the beagleboard classic/xM expansionboards, but I don't know if all 3rd party vendors honour that standard. I know the Ettus USRP E-100 on my desk has it.
regards,
Koen
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