gadgetsetup.sh

#!/bin/bash

GADGETNAME="somegadget"
SERIAL="deadbeefdeadbeef"
MANUFACTURER="n0rc"
PRODUCT="RPi Zero W USB Keyboard"

modprobe libcomposite
cd /sys/kernel/config/usb_gadget/

mkdir -p "$GADGETNAME"
cd "$GADGETNAME"

echo 0x1d6b > idVendor  # Linux Foundation
echo 0x0104 > idProduct # Multifunction Composite Gadget
echo 0x0100 > bcdDevice # v1.0.0
echo 0x0200 > bcdUSB    # USB2

mkdir -p strings/0x409
echo "$SERIAL" > strings/0x409/serialnumber
echo "$MANUFACTURER" > strings/0x409/manufacturer
echo "$PRODUCT" > strings/0x409/product

mkdir -p functions/hid.usb0
echo 1 > functions/hid.usb0/protocol
echo 1 > functions/hid.usb0/subclass
echo 8 > functions/hid.usb0/report_length
echo -ne "\x05\x01\x09\x06\xa1\x01\x05\x07\x19\xe0\x29\xe7\x15\x00\x25\x01\x75\x01\x95\x08\x81\x02\x95\x01\x75\x08\x81\x03\x95\x05\x75\x01\x05\x08\x19\x01\x29\x05\x91\x02\x95\x01\x75\x03\x91\x03\x95\x06\x75\x08\x15\x00\x25\x65\x05\x07\x19\x00\x29\x65\x81\x00\xc0" > functions/hid.usb0/report_desc

mkdir -p configs/c.1/strings/0x409
echo "Config 1" > configs/c.1/strings/0x409/configuration
echo 250 > configs/c.1/MaxPower
ln -s functions/hid.usb0 configs/c.1/
ls -1 /sys/class/udc/ > UDC