This chapter and the following two chapters, Debugging, Testing, and Tuning Device Drivers and Recommended Coding Practices, provide detailed information about developing a device driver.
Take the following steps to build a device driver:
Write, compile, and link the new code.
See Driver Code Layout for the conventions on naming files. Use a C compiler to compile the driver. Link the driver using ld(1). See Compiling and Linking the Driver and Module Dependencies.
Create the necessary hardware configuration files.
Create a hardware configuration file unique to the device called xx.conf where xx is the prefix for the device. This file is used to update the driver.conf(5) file. See Writing a Hardware Configuration File. For a pseudo device driver, create a pseudo(5) file.
Copy the driver to the appropriate module directory.
Install the device driver using add_drv(8).
See Installing Drivers with add_drv. Use the update_drv(8) command to make any changes to the driver. See Updating Driver Information.
Load the driver.
The driver can be loaded automatically by accessing the device. See Loading and Unloading Drivers. Drivers can also be loaded by using the modload(8) command. The modload command does not call any routines in the module and therefore is useful for testing. See Loading and Unloading Test Modules.
Test the driver.
Drivers should be rigorously tested in the following areas:
For additional driver-specific testing, see Testing Specific Types of Drivers.
Remove the driver if necessary.
Use the rem_drv(8) command to remove a device driver. See Removing the Driver.