Only with intimate knowledge of the hardware you are making a driver for, and most companies do not provide detailed specifications for the hardware they sell.
If you are interested in driver development; start by getting a cheap computer, install linux and start studying the source code for the driver in that.
hey grey you are right
but..ummm...
this is my problem
I have a modem that can work in xp and vista only
but I want to change my os to linux,its mean I cant surfing intrnet again,
thats why I try to make driver by my self,
anyone can help me?