Actually i am asking below questions to decide between registering my driver as
character driver or
platform driver
1. my first question is at what point of booting module_init of device driver is called?

2.Second one : In my understanding for non hot-plugable device can also be registered as platform device. And we can put platform_driver_register() function in init function to register device. [Dont know if my understanding is fully correct]
My questions regarding this are
a. Will call to platform_driver_register will result into calling probe of the same driver or
b. probe function of driver will be called at later stage when probe for all SOC device is called.

My assumption is probe is called later i.e. after init functions of all driver is done.(assuming driver is compiled into Linux kernel).

My intention is reduce booting time by reducing code in init function of my driver.

The module_init of device driver is called when modprobe is called.
You can register platform driver in other module.

Thank you nini09 for reply,
But i didn't understand your reply "You can register platform driver in other module".