Writing Device Drivers

Overview of the Character Driver Structure

Figure 15–1 shows data structures and routines that define the structure of a character device driver. Device drivers typically include the following elements:

The shaded device access section in the following figure illustrates character driver entry points.

Figure 15–1 Character Driver Roadmap

Diagram shows structures and entry points for character
device drivers.

Associated with each device driver is a dev_ops(9S) structure, which in turn refers to a cb_ops(9S) structure. These structures contain pointers to the driver entry points:

Note –

Some of these entry points can be replaced with nodev(9F) or nulldev(9F) as appropriate.