Hope you are implementing UVC class.
Exposure setting is a Input Terminal Request. So you need to:
a. Add the exposure support in the Input terminal Descriptor
b. Handle the request in the firmware. When you get SET_CUR you will have to configure the image sensor accordingly.
For general example code refer to KBA articles:
Thank you for reply
Is there any other method? to change exposure
Instead of using UVC you can develop your own application using the vendor class. Please refer to Aptina_Cypress_FX2LP_Ref_Design in the KBA article - KBA95736 (link is provided in the previous response).
If you are implementing UVC then exposure support should be adder in the GUI and the request to the firmware from the GUI should initiate i2c commands to the image sensor where the respective registers which are set for the exposure are written with the needed exposure values.