I am trying to port Fedora-IoT 33/34 on Raspberry PI CM3. I am trying to interface a DAC IC namely dac082s085. I want to using IIO framework and I am using ti-dac082s085 driver from “https://github.com/RevolutionPi/linux/blob/revpi-4.19/drivers/iio/dac”
Since I found-out that Fedora doesn’t have dac082s085 driver and therefore I didn’t find iio:device corresponding to the DAC. I set up a host machine with latest Fedora 33/34 and compiled the RevPi kernel (from Git) for armv7hl. After solving couple of issues regarding vermagic and stuff, I am able to load kernel module. Initially, I got the below error:
[14586.398801] ti_dac082s085: Unknown symbol __stack_chk_guard (err -2)
[14586.399281] ti_dac082s085: Unknown symbol __stack_chk_fail (err -2)
After disabling STACK PROTECTOR in the kernel. Now I am getting the following error:
[ 712.552076] Unable to handle kernel paging request at virtual address 7e7b9f64
[ 712.552681] pgd = 8f6c4b5b
[ 712.552893] [7e7b9f64] *pgd=00000000
I also updated memory@0 in dtb file from:
reg = <0x00 0x00> ----to---- reg = <0x00 0x40000000>
But I am still getting the same error.
Below is the stripped “modinfo” output of the ti_dac082s085.ko module:
vermagic: 5.11.0-156.fc34.armv7hl SMP mod_unload ARMv7 p2v8
Raspberry PI CM3 (with Fedora-IoT 33/34) “uname -a”:
Linux fedora 5.11.0-156.fc34.armv7hl #1 SMP Wed Feb 17 09:24:49 UTC 2021 armv7l armv7l armv7l GNU/Linux
I am not sure if the above errors are related to any Kernel configuration or something related to RaspberryPI. How can I solve this?
P.S: industrialio driver (which is the dependency of ti_dac082s085.ko module is already loaded).
[root@fedora ~]# lsmod | grep industrialio
industrialio 77824 2 mcp320x,iio_mux
Can you please help us finding any direction to solve this problem ??