Hello yusup khan,
we have examples Software Development Kit for Kinetis MCUs|Freescale for USB Stack OTG.
But unfortunately I have not found the example for MKL26 for OTG (in SDK are only examples for TWR-K*) there we also have examples for HID, CDC, MSD... for FRDM-KL26Z.
You can look at the source code at <ksdk path>\usb\usb_core\otg\sources
Please, see also our documentation dedicated USB at <ksdk path>\doc\usb
Please, let me know if the information helps you.
Best Regards,
Iva