This page contains a list of specifications used to write Linux drivers for several wireless cards, and which, alternatively, can be used to write drivers for any other platforms.
Broadcom hardware specifications
The b43 driver was written based on the reverse engineered specification. This device currently is known to use two different firmware types, each of which changes the behavior of the driver. Because of this we have two different drivers for each handle each firmware. Fortunately we have specifications written for both firmwares.
Atheros has released their legacy under the ISC license
Sam Leffler's HAL
Atheros has worked with Sam Leffler to allow him to release his HAL. You can get it through svn:
svn co http://svn.freebsd.org/base/projects/ath_hal
Atheros engage further with active upstream developers.
This is new and ongoing project.
Ralink has provided EEPROM channel documentation on two of their chipsets.
This is a p54 variant used in some mobile devices.