cm4_wifi_detect.sh

#!/bin/bash

rpi_revision_code() {
        # see https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#new-style-revision-codes
        code=$(grep Revision /proc/cpuinfo  | cut -f 2 -d \: | xargs)

        echo $((16#${code}))
}

rpi_type() {
        code=$(rpi_revision_code) 
        mask=4080

        echo $(((code & mask) >> 4))
}

is_cm4() {
        test $(rpi_type) -eq 20
}


is_cm4_with_wifi() {
        is_cm4 && grep -q 'DRIVER=brcmfmac' /sys/class/ieee80211/phy0/device/uevent 2>/dev/null
}

if is_cm4; then
        echo "I'm a RPi CM4"
fi

if is_cm4_with_wifi; then
        echo "I'm a RPi CM4 with WiFi"
fi