> >>> At the end of the line, some kind of hardware glue is going to be needed. > >>> > >>> I just feel that drawing from a sample size of 1 (maybe 2 if I get to > >>> throw > >>> in the beagleboard), it is a bit premature to think about making it overly > >>> general, besides the part that are obviously part of the infrastructure > >>> (like the DT overlay stuff). > >>> > >>> What I'm getting at, is that we need some user experience about this, > >>> before > >>> going away and creating structure out of possible misconception about the > >>> uses. > >> > >> IMHO stuff like this will be needed by many SoCs. Some examples of similar > >> things for omaps that have eventually become generic frameworks have been > >> the clock framework, USB OTG support, runtime PM, pinmux framework and > >> so on. > >> > >> So I suggest a minimal generic API from the start as that will make things > >> a lot easier in the long run. > > > > I agree. The ux500 platform already has the concept of "user interface > > boards", > > which currently is not well integrated into devicetree. I believe Sascha > > mentioned that Pengutronix had been shipping some other systems with add-on > > boards and generating device tree binaries from source for each combination. > > > > Ideally, both of the above should be able to use the same DT overlay logic > > as BeagleBone, and I'm sure there are more of those. > > Hmm, I see. > > I will need some more information about the interface of the 'user interface > boards'. > I.e. how is the board identified, what is typically present on those boards, > etc.
User Interface Boards are mearly removable PCBs which are interchangeable amongst various hardware platforms. They are connected via numerous connectors which carry all sorts of different data links; i2c, spi, rs232, etc. The UIB I'm looking at right now has a touchscreen, speakers, a key pad, leds, jumpers, switches and a bunch of sensors. You can find a small example of how we interface to these by viewing 'arch/arm/boot/dts/stuib.dtsi'. To add a UIB to a particular build, we currently include it as a *.dtsi from a platform's dts file. > Can we get some input by the owner of other similar hardware? I know the FPGA > people have similar requirements for example. There are other people that are > hitting > problems getting DT to work with their systems, like the V4L people with the > order > of initialization; see http://lwn.net/Articles/531068/. I think the V4L > problem is > cleanly solved by the overlay being contained in the V4L device node and > applied just before > the device is probed. > > In the meantime it would be better to wait until we have some ack from the > maintainers > of the core subsystems about what they think. > > Regards > > -- Pantelis > -- Lee Jones Linaro ST-Ericsson Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
