Fedora IOT: raspberry PI4 i2c not available

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#1

Hi,

I have installed Fedora IOT 36 on a raspberry PI4+ 4GB.
I miss the I2C devices 0 and 1. I can only find 20 and 21.

# uname -a
Linux microshift 5.18.13-200.fc36.aarch64 #1 SMP PREEMPT_DYNAMIC Fri Jul 22 13:44:25 UTC 2022 aarch64 aarch64 aarch64 GNU/Linux
# i2cdetect -l
i2c-20	i2c       	Broadcom STB :                  	I2C adapter
i2c-21	i2c       	Broadcom STB :                  	I2C adapter
# journalctl -b|grep i2c
Jul 14 00:00:00 fedora kernel: brcmstb-i2c fef04500.i2c:  @97500hz registered in polling mode
Jul 14 00:00:00 fedora kernel: brcmstb-i2c fef09500.i2c:  @97500hz registered in polling mode
Jul 14 00:00:10 microshift kernel: i2c_dev: i2c /dev entries driver
Jul 14 00:00:10 microshift systemd-modules-load[548]: Inserted module 'i2c_dev'
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#2

Unfortunately, raspberry Pi4 support is still emerging and even things like accelerated graphics aren’t there yet in 36, but it will be fully supported in Fedora 37. You might try it out when the 37 beta is cut in the coming months.

#3

Just an FYI.
Fedora 37 has been branched from rawhide, so it can now be followed separately.

I do not like fedora IOT since it is immutable like silverblue. I understand why, but not my preference for a Pi.

#4

Sure, I just wanted to be cautious that while full support of Pi4 is the target for f37, I didn’t want to give the impression that the current state of f37 represents that status. That said, the nice thing about ostree systems like IoT is that you can always downgrade back to 36 if it doesn’t work.

#5

Thanks for your information.

The trick is very simple. Just add in the /boot/boot/config.txt
dtparam=i2c_arm=on

# i2cdetect -l
i2c-1    i2c           bcm2835 (i2c@7e804000)              I2C adapter
i2c-20    i2c           Broadcom STB :                      I2C adapter
i2c-21    i2c           Broadcom STB :                      I2C adapter

or add
dtoverlay=pwm,pin=18,func=2

#ls /sys/class/pwm/pwmchip0
device  export  npwm  power  subsystem  uevent  unexport  

# lsmod|grep pwm
pwm_bcm2835            16384  0
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#6

sorry, one typo: the config is in /boot/efi/config.txt