Gilco, could you post the code you ended up using to get this to work? I am in the same boat, I just want to use some GPIO pins for basic I/O but this new device tree thing is making it hard. Cannot find any information on how to simply export a few pins. I would really appreciate any help! ~Dagaen Golomb
On Wednesday, May 14, 2014 8:45:59 PM UTC-4, Gilco333 wrote: > > Thank you, definitely valuable tips! :-) > > On Thursday, May 15, 2014 3:14:39 AM UTC+3, RobertCNelson wrote: >> >> >> >> >> On Wed, May 14, 2014 at 7:07 PM, Gilco333 <cohen...@gmail.com> wrote: >> >>> Wow, thank you Robert for the super quick answer :-) >>> >>> A short question before I'll read and delve into more depth about the >>> subject: >>> I have noticed during the boot process, the beagleboard-xM (rev B) >>> prints on screen: >>> >>> "reading /dtbs/omap3-beagle-xm-ab.dtb >>> 60695 bytes read in 13 ms (4.5 MiB/s) >>> ## Error: "expansion_args" not defined >>> >> >> That's just an old variable in u-boot for the old "board" file boot. (the >> buddy=spidev etc crap) >> >> >>> >>> Kernel image @ 0x80300000 [ 0x000000 - 0x3e2f38 ] >>> ## Flattened Device Tree blob at 815f0000 >>> Booting using the fdt blob at 0x815f0000 >>> Using Device Tree in place at 815f0000, end 81601d16 >>> >>> Starting kernel .." >>> >>> So I searched for the omap3-beagle-xm-ab.dts (on linux_kernel-3.14.4 >>> source) in order to modify it. but couldn't find it, found only >>> omap3-beagle-xm.dts >>> googled and found only this skinny file: omap3-beagle-xm-ab.dts, which >>> contains: >>> >> >> Yeah, just got merged to mainline a few weeks back. >> >> >> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/omap3-beagle-xm-ab.dts?id=refs/tags/v3.15-rc5 >> >> >>> /include/ "omap3-beagle-xm.dts" >>> >>> /* On Rev A/B USBHOST_PWR_EN is active high */ >>> >>> &hsusb2_power { >>> >>> enable-active-high; >>> >>> }; >>> >>> Is it the correct file? which I should: >>> 1) modify >>> 2) compile it to dtb >>> 3) overwrite the exist file in /boot/uboot/dtbs/omap3-beagle-xm-ab.dtb >>> >> >> >> It's actually way easier to just "decompile" it with dtc, then recompile >> it again. >> >> dtc -I dtb -O dts omap3-beagle-xm-ab.dtb > omap3-beagle-xm-ab.dts >> >> Regards, >> >> -- >> Robert Nelson >> http://www.rcn-ee.com/ >> > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
