USB Subsystem

[Arjun Joshi]

Hi All,

I am new to this mailing list and to the linux kernel. So the question 
below might seem a little simple. Ok here goes..

I read that "struct bus_type" object is registered with the driver core 
when the specific  subsytem is loaded in the kernel.

Now in context of USB, I want to know at which point is the USB 
subsystem loaded in the kernel  and what will be the next sequences of 
registrations in the driver core?

In the linux kernel the "struct device" or "struct device_driver" object 
are embedded in a higher layer structure. What is the reason for 
designing the kernel in the above way?

Thank you in advance,
AJ