Thanks 1%,
I tried with the file from your repo but without result.
ptp-ml.o: In function `ptp_handler_PTP_ML_CODE':
ptp-ml.c:(.text+0x308): undefined reference to `send_ptp_data'
ptp-ml.c:(.text+0x3c8): undefined reference to `send_ptp_data'
ptp-ml.c:(.text+0x458): undefined reference to `send_ptp_data'
ptp-ml.c:(.text+0x4c4): undefined reference to `send_ptp_data'