... 2nd Edition June 2001 . ... The goal of this chapter is to write a complete char device driver. ... Our ultimate aim is to write a modularized char driver, but we won't talk about modularization issues in this chapter. ... Later, in the section "Access Control on a Device File" in Chapter 5, "Enhanced Char Driver Operations", the code for sculluid will demonstrate how the driver can enforce its own kind of authorization for device access. ... Back to: Linux Device Drivers, 2nd Edition . ...