Changing I2C pins through /boot/config.txt failed

Question

I'm trying to get the libcamera-still to work on a compute module 4 with an imx219 but I'm getting a

ERROR: *** no cameras available ***

Running dmesg returns

[    6.060283] pinctrl-bcm2835 fe200000.gpio: pin gpio44 already requested by fe804000.i2c; cannot claim for soc:i2c0mux
[    6.060310] pinctrl-bcm2835 fe200000.gpio: pin-44 (soc:i2c0mux) status -22
[    6.060331] pinctrl-bcm2835 fe200000.gpio: could not request pin 44 (gpio44) from group gpio44  on device pinctrl-bcm2711
[    6.060350] i2c-mux-pinctrl soc:i2c0mux: Error applying setting, reverse things back
[    6.060370] imx219 10-0010: failed to read chip id 219

So I'm guessing it's probing the I2C bus at startup for a camera but the pins are still routed to the default pins so there is obviously no answer.

If I run raspi-gpio set 44 a2 and raspi-gpio set 45 a2 I can communicate with the camera but at this point its apparently too late for the libcamera.

So how do I make the pi use the gpio pins 44/45 for I2C at startup?

My /boot/config.txt looks something like this

dtparam=i2c1=on
#dtparam=i2c0=on
dtparam=i2c_arm=on

dtoverlay=i2c1,pins_44_45

#dtparam=i2s=on
#dtparam=spi=on

# dtoverlay=i2c-gpio,bus=5
# dtoverlay=i2c-gpio,bus=4
# dtoverlay=i2c-gpio,bus=3

# Uncomment this to enable infrared communication.
#dtoverlay=gpio-ir,gpio_pin=17
#dtoverlay=gpio-ir-tx,gpio_pin=18

# Additional overlays and parameters are documented /boot/overlays/README

# Enable USB
dtoverlay=dwc2,dr_mode=host

# Enable audio (loads snd_bcm2835)
#dtparam=audio=on

[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dtoverlay=vc4-kms-v3d
max_framebuffers=2

[all]
#dtoverlay=vc4-fkms-v3d
start_x=1
gpu_mem=256

dtoverlay=imx219

Answer 1

Try this:

dtoverlay=i2c-gpio,i2c_gpio_sda=44,i2c_gpio_scl=45,i2c_gpio_delay_us=1,bus=0

Replace your i2c bus number bus=<bus no>

Note:

Make sure you have installed kernel modules:

• kmod-i2c-bcm2835
• kmod-i2c-gpio
• kmod-i2c-core
• kmod-i2c-smbus

For more details read /boot/overlay/README