How Do I see changes made to kernel Module

How Do I see changes made to kernel Module

I am New to Linux kernel , I have Module running on my Linux Machine and
can see it using lsmod command ,Now I made some changes(added some printk)
to this moudule ,recompiled again and got the .ko again.Now I did rmmod to
remove this module(some other modules also which are using this module)
and did insmod xxx.ko and reboot the system .
Now where Do I see the statements added using printk ,I tried to see using
dmesg grep | "SPI RW"
But couldn't find anything .Could anybody let me know what I am doing
wrong here??