AD7124 pyadi-iio rx() function is constant

Hi Bowei , the link you have provided is correct. The  move to change rpi-ad7124-8-all-diff-cs0-int25-overlay.dtbo to rpi-ad7124-8-all-diff.dtbo was to make the cs and interrupt pins reconfigurable at boot time via device tree overlay parameters. This way, we could use either of the 2 SPI ports of PMD-RPI-INTZ Evaluation Board | Analog Devices without the need to recompile the device tree.

To obtain the same configuration as rpi-ad7124-8-all-diff-cs0-int25-overlay.dtbo, we could use this in the /boot/config.txt instead:

dtoverlay=rpi-ad7124-8-all-diff,cs_pin=0,irq_gpio=25


As for the rx() being constant, there is an existing driver issue present in branch rpi-5.15.y (2022_r2)  that is being looked upon. This might be the cause of rx() readings being constant.

(+) Inconsistent channel position in a libiio buffer - Q&A - Linux Software Drivers - EngineerZone (analog.com)

Hi Kimpaller,

Thanks for the reply! It might be the same problem. In any case, could you reproduce my problem using

Sorry Bowei unfortunately, I don't have an eval-ad7124-8sdz I could use right now. The issue on the libiio buffer was communicated to the developers  and looks like it affects any device using the ad7124 driver (cn0554, eval-ad7124-8-pmdz, cn0508). I believe there is a fix in rpi-6.1.y branch  (analogdevicesinc/linux at rpi-6.1.y (github.com) which will be part of 2023_R2 (not yet released). I'm still trying this myself and would love to update you on the result

I see. Do I need to build the rpi-6.1.y branch linux driver according to https://wiki.analog.com/resources/tools-software/linux-build/generic/raspberrypi or is there a prebuilt version available for download?

Yes, there are pre-built files from the latest build of rpi-6.1.y.

Download them from:
https://swdownloads.analog.com/cse/linux_rpi/rpi-6.1.y/rpi_latest_boot.tar.gz (should be  extracted in /boot)
https://swdownloads.analog.com/cse/linux_rpi/rpi-6.1.y/rpi_modules.tar.gz  (should be extracted in  /lib/modules)


Unfortunately, there is no rootfs yet for 2023_R2 but we could try the above files on an existing 2022_R2 image, though it is not guaranteed to work yet.

Thank you so much for the links! I am not very familiar with the Linux file structure. Right now on my Raspberry Pi, which has 2022_R2 Kuiper Linux installed, shall I delete the contents of /boot and /lib/modules directories, and put the files in your links into the respective directories? The rpi_modules link has 3 folders, which one should I use?

No need to delete, I just usually overwrite (/boot and /lib/modules) by copying all files as it is.
Its fine to copy all the 3 folders under rpi_modules to /lib/modules but if you are constrained with storage, you could just copy the folder that corresponds to your RPI variant,
ex. RPI4 -> 6.1.54-v7l+, RPI3 -> 6.1.54-v7+

Hi Kimpaller, I extracted the files as you said, but now when I use iio_info command, it can not find the ad7124 device. I also don't see an error loading the device tree overlay, so I guess the new kernel is not loading the device tree. Could you get the kernel to work properly for rpi-6.1.y?

Hi Kimpaller, I extracted the files as you said, but now when I use iio_info command, it can not find the ad7124 device. I also don't see an error loading the device tree overlay, so I guess the new kernel is not loading the device tree. Could you get the kernel to work properly for rpi-6.1.y?