Really loving the Nerves system I am trying to get hardware PWM working on Nerves on a RPI4. I had this working on Raspbian before. For Nerves, I was able to customize things to get the dtoverlay added in /boot/config.txt and having the pwm.dtbo file copied into /boot/overlays as well - these by using the custom fwup.conf etc.
But after this I still don’t have a /sys/class/pwm present in my sysfs.
I tried adding dtdebug=1 to config.txt too, but that didn’t give me more info in dmesg.
So I am now thinking that I’m missing the appropriate kernel module, thinking I need to have the pwm-bcm2835.ko which is not present in kernel/drivers.
I also checked the linux-4.19.defconfig and nerves_defconfig in the nerves_system_rpi4 repo and could not find any mention of CONFIG_PWM_BCM2835.
Does this mean I will have to clone the nerves_system_rpi4 repo, make my own changes and have the kernel recompiled in order to get this kernel module ?
Did someone else try to make this work earlier ?
Hoping to get some more info before I go down this rabbithole only to find out there’s an easier way