how to implement mmap for sysfs device driver

Hi all, I want to implement a device driver with mmap operations. However, I am not using ioctl call. My approach: i. I have created a sysfs bin files (because it support mmap) ii. Now, I have implemented my mmap in my driver and assign this attribute to the sysfs file I have created. However, I am facing the problem. The mmap is being called properly, however mmap_fault my implementation is not being called as a result of which the memory is not mapped. So, when I try to access this file I get segmentation fault. Can you please suggest what I should modify or is there anyother way to do it other than this ?? Thanking you in advance. Thanks and Regards, Niroj Pokhrel