On 11/09/2012 09:28 AM, Grant Likely wrote: > On Tue, Nov 6, 2012 at 10:37 PM, Stephen Warren <swarren@xxxxxxxxxxxxx> wrote: ... >> I do rather suspect this use-case is quite common. NVIDIA certainly has >> a bunch of development boards with pluggable >> PMIC/audio/WiFi/display/..., and I believe there's some ability to >> re-use the pluggable components with a variety of base-boards. >> >> Given people within NVIDIA started talking about this recently, I asked >> them to enumerate all the boards we have that support pluggable >> components, and how common it is that some boards support being plugged >> into different main boards. I don't know when that enumeration will >> complete (or even start) but hopefully I can provide some feedback on >> how common the use-case is for us once it's done. > > From your perspective, is it important to use the exact same .dtb > overlays for those add-on boards, or is it okay to have a separate > build of the overlay for each base tree? I certainly think it'd be extremely beneficial to use the exact same child board .dtb with arbitrary base boards. Consider something like the Arduino shield connector format, which I /believe/ has been re-used across a wide variety of Arduino boards and other compatible or imitation boards. Now consider a vendor of an Arduino shield. The shield vendor probably wants to publish a single .dtb file that works for users irrespective of which board they're using it with. (Well, I'm not sure that Arduino can run Linux; perhaps that's why you picked BeagleBone capes for your document!) I suppose it would be acceptable for the shield vendor to ship the .dts file rather than the .dtb, and hence need to build the shield .dtb for a specific base board. However, I think the process for an end-user needs to be as simple as "drop this .dts/.dtb file into some standard directory", and I imagine it'll be much easier for distros/... to make that process work if they're dealing with a .dtb that they can just blast into the kernel's firmware loader interface, rather than having to also locate the base-board .dts/.dtb file, and run dtc and/or other tools on both .dts files together. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
