How do I change the ad9361_clk_sel line so that I can provide an external reference?
export 1011 > /sys/class/gpio/export provides a resource busy error.
reading from /sys/kernel/debug/gpio shows the ad9361_clk_sel and indicates that is being used by gpiochip0. Can I somehow set the gpio line through gpiochip0, if so how?
See here: wiki.analog.com/.../fmc
So, one must modify the device tree and rebuild the project to use an external reference rather than choosing the reference clock at runtime?
spydell said: rebuild the project
Not really sure what you mean by this.
You just need to modify the device tree and reboot to load it.
I'm not all that familiar with device trees. And as far as I can tell there is no device tree source that I can simply modify; the only device tree file I see is the binary. So, I'm assuming this means I need to download the device tree source file that your wiki page link mentions, make the edits, compile the new device tree, load it onto the boot partition of the SD card, and then reboot the ADRV?
You can actually do everything from the board: https://wiki.analog.com/resources/eval/user-guides/ad-fmcomms2-ebz/software/linux/zynq_tips_tricks